OBJECTIVE:To provide references for medical workers about how to make better use of the PubMed to retrieve foreign literature.METHODS:The PubMed was introduced in detail with example in respect of the retrieving method,special service function,use of special column,storing and printing of retrieving results,etc.RESULTS & CONCLUSIONS:PubMed is generally accepted as one of the most important and authoritative biomedical bibliographic database and its contents cover each field of biomedicine.Mastering the methods and skills of retrieving PubMed is of great help for medical workers to retrieve foreign literature rapidly and accurately.

Oral drug-loaded nano-system include nano-gel drug delivery system, nano-suspension drug delivery system, nano-particle drug delivery system, liposomes drug delivery system, nano-micelles drug delivery system, alcohol liposoms,nano-framework drug delivery system, nano-emulsions drug delivery system, nano-self assembly drug delivery system.These nano-drug delivery systems can serve as multi-functional drug carriers.They may significantly improve the physicochemical and stabilization and biological properties of the free drug, enhance the therapeutic efficiency and reduce toxic side effects.This paper reviews the recent research progress in oral drug-loaded nano-systems.