摘要：Objective The research investigated whether conducting a supplementary search of PubMed in addition to the main MEDLINE (Ovid) search for a systematic review is worthwhile and to ascertain whether this PubMed search can be conducted quickly and if it retrieves unique, recently published, and ahead-of-print studies that are subsequently considered for inclusion in the final systematic review. Methods Searches of PubMed were conducted after MEDLINE (Ovid) and MEDLINE In-Process (Ovid) searches had been completed for seven recent reviews. The searches were limited to records not in MEDLINE or MEDLINE In-Process (Ovid). Results Additional unique records were identified for all of the investigated reviews. Search strategies were adapted quickly to run in PubMed, and reviewer screening of the results was not time consuming. For each of the investigated reviews, studies were ordered for full screening; in six cases, studies retrieved from the supplementary PubMed searches were included in the final systematic review. Conclusion Supplementary searching of PubMed for studies unavailable elsewhere is worthwhile and improves the currency of the systematic reviews. Keywords and Medical Subject Headings (MeSH) Databases, Bibliographic; Information Storage and Retrieval; Medical Subject Headings; MEDLINE; PubMed; Review Literature as Topic When conducting comprehensive literature searches for systematic reviews of health care interventions, searchers almost always include one bibliographic database, MEDLINE. MEDLINE content can be searched via several search interfaces, the majority of which are provided by fee-based subscription services (e.g., Ovid, EBSCO, or ProQuest), although it can be accessed for free using PubMed. When searching for systematic reviews, PubMed has been shown to have a higher retrieval rate than fee-based versions of MEDLINE, such as Ovid [ 1 ]. PubMed enables users to search MEDLINE, PubMed citations that will never be indexed on MEDLINE, and other sources, such as online books. Despite this and the fact that PubMed is freely available, many information specialists prefer to search using sophisticated interfaces (usually fee-based) that enable the design of complex search strategies. PubMed has relatively limited search capabilities. For example, proximity searching is not possible and truncation is limited to the first 600 variations. The lack of proximity search operators can be a significant hindrance when attempting to conduct searches for systematic reviews in PubMed, as phrase searching or use of the Boolean “AND” to combine terms are the only alternatives. This can produce a search strategy that is either too precise when using phrases or too sensitive when using the Boolean “AND.” Searching MEDLINE via more sophisticated interfaces enables much greater flexibility when conducting searches for systematic reviews, allowing information specialists to find a better balance between precision and sensitivity that is not possible in PubMed. Migration of records from PubMed into fee-based subscription services is usually quite timely. Studies indicate that indexed MEDLINE records and MEDLINE In-Process records can be available on Ovid within 2–3 days of being available on PubMed [ 2 , 3 ]. However, 2% of PubMed records are still not found on MEDLINE [ 2 ], as fee-based subscription services such as Ovid do not provide the subset of PubMed that includes ahead-of-print articles [ 4 ]. The “ahead of print” citations preceding the article's final publication are of particular interest to this investigation [ 5 ]. Ahead-of-print citations do not move to In-Process on PubMed until their publication in final or print format.
关键词：Keywords and Medical Subject Headings (MeSH) Databases; Bibliographic; Information Storage and Retrieval; Medical Subject Headings; MEDLINE; PubMed; Review Literature as Topic
