Chemical Literature (Chem 184/284)

Lecture 12: Chemical Abstracts Online, Part 1

Chemical Abstracts Online

Just as Chemical Abstracts is the single most important printed tool for chemical information, so its online counterpart is the most important electronic source.
Electronic CA is made available through several vendors, including DIALOG, DataStar, Ovid, Orbit, Questel, ESA-IRS, and STN International. We will be using STN.

STN International

STN International is a cooperative service of three database providers:

Chemical Abstracts Service (CAS) (Columbus, Ohio)
Fachinformationzentrum Karlrsruhe (FIZ Karlsruhe) (Karlsruhe, Germany)
Japan Information Center for Science and Technology (JICST) (Tokyo, Japan)

STN Command Language

As on the MELVYL system and most online systems, STN uses a specific command language to carry out its functions. STN's command system is called Messenger. Though there are many commands to cover a wide variety of functions, most basic searching can be carried out with a handful of commands.
See also the STN Basics tutorial section at http://www.cas.org/training/basics/page2.html#anchor4pg2 or Online Searching Basics at http://www.cas.org/ACAD/lesson1.html

FILE Command

FILE is used to switch from one database to another.
To use it, type file followed by the name of the database, e.g.

        => file ca
        => file inspec

You can also enter multiple file names or the names of file clusters.

        => file biosis, ca, lifesci
        => file patents

EXPAND Commnad

This is the equivalent of the MELVYL "browse" command, and allows you to scan a portion of a particular index and see both the terms which appear there and the number of records in which each appears.

EXPAND may be abbreviated as EXP or simply E.
Usually, each portion of a record has its own index. (e.g. author, title, language, publication year.)
When expanding or searching, you can specify an index by following your search term with a slash (/) and the code for the index desired (au, ti, la, py)

        => expand huber c/au
        => e enzyme/ti

In addition, each file has a basic index, which is the default index searched if you don't specify a particular index.
The fields included in the basic index may vary from file to file.
In most bibliographic files, it includes terms from the title, abstract and subject headings.
In response to the EXPAND command, the system will display a portion of the index with the term you used at the third position (there may or may not be any records with that term.)
It will display 12 terms unless you specify otherwise.
By entering e again, you can see more of the list.

=> e fragran 6
E1              1 FRAGRAEA/BI
E2              1 FRAGRAMENTS/BI
E3              0 FRAGRAN/BI
E4        1226 FRAGRANCE/BI
E5          158 FRAGRANCES/BI
E6              3 FRAGRANOL/BI

The E# corresponding to a listed term may be used as a substitute for the term in either further EXPANDs or SEARCHes.
Note that, in Messenger, a subsequent EXPAND command normally wipes out the first list, so you must use any E#'s you wish to search on before doing a second EXPAND.

SEARCH Command

SEARCH commands the system to locate records containing your terms in the index(es) you designate.
SEARCH may be abbreviated SEA or S.
Searches generate answer sets which are designated with L numbers. The L#'s may then be used in display commands, or reused as search terms.

=> s fragrance
L1      1226 FRAGRANCE
=> s perfume
L2       869 PERFUME
=> s L1 or L2
L3      1835 L1 OR L2

Truncation

Like most electronic search systems, Messenger allows truncation of terms, but with much greater flexibility than most.
"#" is treated as 0 or 1 character at the end of a word. So child### will catch "child", "child's", "children", "childish"
"!" is used as a wild card character in the middle of a word. So analys!s will catch "analysis" or "analyses"
"?" represents any number of characters, usually at the end of a word. So photo? will catch "photo", "photos", "photolysis", "photographic", "photochemical", etc.
In some indexes, most notably the Basic Index in the CA file, you can use ? on the lefthand side of a term. So ?fluorocarbon will pick up "fluorocarbon", "perfluorocarbon", "chlorofluorocarbon", etc.
Where lefthand truncation is available, you can combine left and right truncation, e.g. ?porph? will pick up "porphyrin", "tetraphenylporphyrins"

Operators

See also STN Proximity Operators at http://www.cas.org/training/basics/page5.html#anchor2pg5

Messenger uses the standard Boolean operators: AND, OR and NOT, as well as a variety of specialized operators.
Proximity operators allow you to specify the relationships between terms.
- (W) (not W) -- Looks for terms next to each other in the order given. If you enter two terms with no operator between them, Messenger assumes the (W) operator, so s magnetic resonance is the same as s magnetic (W) resonance.
- (nW) (notnW) -- Looks for terms up to n words apart in the given order: s nuclear (1w) resonance will pick up nuclear magnetic resonance or nuclear quadrupole resonance.
- (A), (notA), (nA), (notnA) -- Same as above, but terms can be in either order.
- (S), (notS) -- Looks for terms in the same sentence. This is very useful for searching abstracts or full-text files.
- (L), (notL) -- Looks for terms in the same indexing unit, e.g. abstract, index phrase, keyword phrase.
Numeric operators work with numeric fields, such as publication year (PY) to specify ranges.
- = equal to
- >: greater than
- < less than
- >= or => greater than or equal to
- =< or <= less than or equal to
- nnnn-mmmm specifies a range.
Order of Precedence
FIRST
- Expressions in parentheses
- Numeric operators
- (W), (notW), (nW), (notnW), (A), (not A), (nA), (notnA)
- (S), (notS)
- (L), (notL)
- AND, NOT
- OR
LAST

DISPLAY Command

DISPLAY is used to show answers from an answer set (or other displayable items).
DISPLAY may be abbreviated DIS or D.
In the DISPLAY command, you may specify the answer set, specific answers to be displayed and fields to be displayed, in any order.
```
=> display L2 1, 3-5, 11 bib abs
=> dis all L3 1-
```
Note that in Messenger "all" is a display format (the full record) NOT "all records in a set". To display all records, use "1-"
```
=> d
```
Using the short ("expert") form, Messenger assumes default values: the last answer set, the first record in the set, and the default format (usually "bib").

PRINT Command

PRINT works the same way as DISPLAY, but creates an offline print, which can be sent to you via mail, fax or e-mail.
Do not use PRINT if you want to print directly from the screen display.
PRINT can save money if you have a large volume of records to print and/or a slow online connection and/or a slow printer.

Author Searching (/au)

See also Searching Author Names on STN at http://www.cas.org/ACAD/lesson5.html

In the online files, all author's names can be searched directly -- there's no need to deal with cross-references for co-authors.
Note that in online CA, there is no attempt made to unify the versions of an author's name -- all are listed as they appear in the document - with or without full first name or initials.
Always use EXPAND to check on the forms of the author's name -- even without complicated names, different documents may use different forms.

In CAS files, the general form of author names is:

        lastname firstname m/au
        lastname f m/au

It is often convenient (and cheaper) to search using truncation to pick up variant forms.
```
 => s lastname f?/au
```
But beware of multiple authors with the same lastname and initial. Check with EXPAND first.
Remember that all the rules about umlauts, transliterations, etc. apply online, too.
If you wish to search for patents ONLY, use the Inventor field (/in).
Example:

e st john/au 8
E1      6       st jeor stephen/au
E2      6       st jeor stephen c/au
E3      0 -->   st john/au
E4      1        st john allan k/au
E5      1        st john d j b/au
E6      1        st john fisher ian/au
E7      13       st john manley r/au
E8      1        st john smith p/au

e manley r/au 8
E1      7        manley paul william/au
E2      6        manley philip/au
E3      0 -->   manley r/au
E4      1        manley r m/au
E5      3        manley r s j/au
E6      9        manley r s john/au
E7      7        manley r st j/au
E8      47       manley r st john/au

Corporate Source (/cs)

Note that the Corporate Source field unlike the Author field, contains both individual words and phrases.
Note also that corporate names are highly abbreviated, and names may vary with time.
Use EXPAND to check search terms and search the minimun necessary distinctive terms.
Example: Du Pont

L2          SEL L1 1- CS :      61 TERMS

TERM #   # OCC  # DOC  % DOC CS
------ ------- ------ ------ ---------------
     1      33     33  23.91 DU PONT DE NEMOURS, E. I., AND CO.
     2      14     14  10.14 DU PONT DE NEMOURS, E. I., AND CO. , USA
     3      10     10   7.25 DU PONT DE NEMOURS, E. I., AND CO., USA
     4       6      6   4.35 CENT. RES. DEV. DEP., E. I. DU PONT DE NEMOUR
     5       5      5   3.62 CENT. RES. DEP., E. I. DU PONT DE NEMOURS AND
     6       4      4   2.90 SAVANNAH RIVER LAB., E. I. DU PONT DE NEMOURS
     7       3      3   2.17 SAVANNAH RIVER LAB., DU PONT DE NEMOURS (E.I.
     8       3      3   2.17 SAVANNAH RIVER LAB., E. I. DU PONT DE NEMOURS
     9       2      2   1.45 DU PONT CO., WILMINGTON, DE, USA
    10       2      2   1.45 E. I. DU PONT DE NEMOURS AND CO., WILMINGTON

Journal Title Searching (/jt)

Journal titles may be searched either as as individual terms or as a bound phrase. Note that titles are in the CASSI abbreviation form.
```
=> s j am chem soc/jt
```
Use EXPAND to be sure of the full abbreviated title.

Limiting Fields

See also Refining Searches on STN at http://www.cas.org/ACAD/lesson6.html

Some fields are primarily useful for narrowing searches.
Document Type (/dt) can be used to limit to or exclude journals (j), patents (p), technical reports (t), books (b), dissertations (d), conference papers (c) or reviews (r).
To limit by language, use the /la field. Remember that this may exclude articles which are available in translated form..
Publication Year (/py) may be searched numerically.
Update Code is used mostly to allow you to repeat a search and limit it to records added since the last search, e.g. => s L1 and up>971201

This page created by Chuck Huber (huber@library.ucsb.edu).