首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2391245篇
  免费   182963篇
  国内免费   4597篇
耳鼻咽喉   31751篇
儿科学   78843篇
妇产科学   68017篇
基础医学   348049篇
口腔科学   66109篇
临床医学   220299篇
内科学   468742篇
皮肤病学   53609篇
神经病学   194948篇
特种医学   89740篇
外国民族医学   702篇
外科学   347583篇
综合类   53632篇
现状与发展   4篇
一般理论   972篇
预防医学   193849篇
眼科学   54466篇
药学   171662篇
  8篇
中国医学   4907篇
肿瘤学   130913篇
  2019年   19195篇
  2018年   26493篇
  2017年   20247篇
  2016年   22587篇
  2015年   25523篇
  2014年   35940篇
  2013年   54285篇
  2012年   73585篇
  2011年   78474篇
  2010年   45949篇
  2009年   44001篇
  2008年   73186篇
  2007年   77979篇
  2006年   78001篇
  2005年   75938篇
  2004年   72914篇
  2003年   69638篇
  2002年   67436篇
  2001年   111878篇
  2000年   114227篇
  1999年   95379篇
  1998年   27152篇
  1997年   24637篇
  1996年   24965篇
  1995年   23688篇
  1994年   21770篇
  1993年   20362篇
  1992年   73839篇
  1991年   71699篇
  1990年   69065篇
  1989年   66519篇
  1988年   61325篇
  1987年   59964篇
  1986年   56561篇
  1985年   53746篇
  1984年   41009篇
  1983年   35276篇
  1982年   21190篇
  1981年   19183篇
  1979年   37631篇
  1978年   27188篇
  1977年   22655篇
  1976年   21211篇
  1975年   22320篇
  1974年   27119篇
  1973年   26455篇
  1972年   24942篇
  1971年   22981篇
  1970年   21719篇
  1969年   20359篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
Glass ionomer restorative cement offers the clinician an alternative to bonded composite resin for restoration of certain lesions in primary teeth. This article details a step-by-step procedure for restoration of a smooth surface carious lesion in a primary incisor using an encapsulated glass ionomer restorative material and reviews advantages and limitations of the cement. A light-hardened glass ionomer liner/base that has proven useful as an enamel and dentin restorative is also described.  相似文献   
994.
To produce hybrids, one member of the parental line is genetically made male-sterile. This male-sterile trait is encoded by mitochondria so that it is maternally inherited. Consequently, the progeny of a male-sterile plant is fully sterile. Nevertheless, during the handling of cytoplasmic male-sterile seed stocks, some mixture with seeds of the maintainer lines can occur. Up to the present time, the only way to check the homogeneity of the cytoplasmic male-sterile seed stock was to grow the plants until flowering time. We have developed a method which can be used immediately after the harvest, allowing us to check samples from both sunflower and sugar beet. We used the mitochondrial plasmid, present only in the maintainer lines, as a probe for the total nucleic acids prepared from the cytoplasmic male-sterile seed stocks which might be contaminated. The signals compared to those of samples artificially contaminated allow us to measure as few as one male-fertile seed in 1000 seeds in a rapid and accurate manner.  相似文献   
995.
International Journal of Clinical Pharmacy - In order to calculate the minimum sterilization process conditions to obtain the generally accepted sterility level (less than 1·10?6...  相似文献   
996.
A detailed examination of quantitative relationships of pharmacological action with plasma and tissue concentrations of indomethacin has been undertaken in the rat, after single oral administration of two sustained release preparations. In this study, drug was assayed by high performance liquid chromatography, whereas antiinflammatory response was assessed through the carrageenin-induced edema test. Significant linear correlations (p less than 0.001) were found between logarithmically transformed percent inhibition of edema and logarithmically transformed plasma, as well as tissue levels of indomethacin. However, the lack of significance for partial correlation regarding tissue concentration, contrary to plasma concentration, suggests that pharmacological response is more closely related to the latter, indicating that antidematous effect is mediated via the circulating drug rather than a local action in target tissues. This assumption is further discussed from the equivalence point of view. The relevance of this type of study in the case of topical administration of indomethacin is addressed as well. Taking into account the predictive value of the rat paw edema test for clinical efficacy, relationships similar to those observed are to be expected in man. The high correlation existing between plasma concentration of indomethacin and its pharmacological effect justifies the development and use of sustained release preparations in order to improve the outcome of treatment with this nonsteroidal antiinflammatory drug.  相似文献   
997.
998.
999.
1000.
A series of new 4-aryl-5-[omega-(4-aryl-1-piperazinyl)alkyl]-2(3H)- oxazolones was synthesized and tested for neuroleptic activity in mice and rats. Several compounds exhibited interesting neuroleptic activity with very low liability to the extrapyramidal side effects. In particular the activity of 4-(4-fluorophenyl)-5-[2-[4-(3,5-dichlorophenyl)-1- piperazinyl]ethyl]-2(3H)-oxazolone (14) was greater than that of butropipazone and fluanisone, while of the same order of that of chlorpromazine; however, the product showed a longer lasting activity and minor ability to produce catalepsy as compared with the reference drugs.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号