Type a search word in the search query box of PubMed homepage, and the system will match the search word with four indexes in turn, such as Mesh Translation Table, Journals TranslationTable, Phrase List and Author Index. If a matching word is found, it will be converted into the corresponding word in the index and then searched.

2. Interception retrieval function

PubMed allows you to use the * symbol as a wildcard for word truncation retrieval. Word truncation function is limited to words, and it is invalid for phrases.

3. Mandatory retrieval function

PubMed allows the use of double quotes to force the system to perform phrase retrieval.

PubMed's data source

The main data sources of PubMed are MEDLINE, OLDMEDLINE, records being processed and records provided by publishers. Data types: journals, reviews and links to other databases.

MEDLINE has collected more than 654.38+06 million bibliographic data (data in 2005) since 654.38+0966, covering medicine, nursing, veterinary medicine, health care system and preclinical science, and the record is marked as [MEDLINE's Published-Index].

Process citation: From August of 1996, nonstandard data provided by MEDLINE's periodical publishers are collected every day. The records of our library only have simple bibliographic information and abstracts, and the records are marked as [Being Published].

OLDMEDLINE: Including 2 million biomedical literatures published from 1950 to 1965. The record of OldMedline has no MeSH field and abstract, and the record is marked as [published-old MEDLINE for pre1966].

Citations provided by publishers (articles not in Medline or Process): electronic documents provided by publishers, and each record is marked as [published-as supplied by publisher].