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   1417597篇
  免费   108138篇
  国内免费   2501篇
耳鼻咽喉   20394篇
儿科学   48699篇
妇产科学   37992篇
基础医学   201624篇
口腔科学   40290篇
临床医学   121781篇
内科学   288185篇
皮肤病学   31626篇
神经病学   112298篇
特种医学   55822篇
外国民族医学   682篇
外科学   213597篇
综合类   28243篇
现状与发展   3篇
一般理论   427篇
预防医学   110225篇
眼科学   30783篇
药学   103797篇
  2篇
中国医学   3163篇
肿瘤学   78603篇
  2021年   11371篇
  2019年   12215篇
  2018年   17412篇
  2017年   13172篇
  2016年   14054篇
  2015年   16175篇
  2014年   22319篇
  2013年   32548篇
  2012年   45800篇
  2011年   48340篇
  2010年   28195篇
  2009年   26470篇
  2008年   44224篇
  2007年   47394篇
  2006年   46916篇
  2005年   46163篇
  2004年   44835篇
  2003年   42927篇
  2002年   40526篇
  2001年   67289篇
  2000年   69651篇
  1999年   59249篇
  1998年   16347篇
  1997年   14737篇
  1996年   15137篇
  1995年   14251篇
  1994年   13556篇
  1993年   12532篇
  1992年   46229篇
  1991年   45136篇
  1990年   43740篇
  1989年   41626篇
  1988年   38311篇
  1987年   37530篇
  1986年   34910篇
  1985年   33508篇
  1984年   24997篇
  1983年   20924篇
  1982年   12107篇
  1981年   11039篇
  1979年   21993篇
  1978年   15233篇
  1977年   12836篇
  1976年   11967篇
  1975年   13014篇
  1974年   15063篇
  1973年   14505篇
  1972年   13290篇
  1971年   12033篇
  1970年   11397篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
991.
One hundred and one children over 1 year of age have had surgery for pelviureteric obstruction over an 11 year period. The common clinical features were abdominal pain, urinary infection or haematuria, but number presented as an incidental finding. Less commonly, the patients presented with an abdominal mass or with hypertension. The diagnosis was usually made on intravenous pyelography (IVP) but in the latter part of the series, renal nuclide scan (RNS) and ultrasonography (US) were preferred. Ninety–three patients had unilateral pyeloplasty, three had bilateral pyeloplasty and five had nephrectomy or heminephrectomy. Whereas initially nephrostomy drainage was used in the majority of patients after pyeloplasty, trend away from nephrostomy evolved in the latter part of the series. With experience, the incidence of postoperative complications was also reduced and there was reduction in the period of hospitalization. Clinical results were consistently satisfactory. Postoperative assessment after pyeloplasty was made by IVP and/or RNS and also US. A review of these investigations showed that RNS provided more factual information of the result when compared with the IVP.  相似文献   
992.
993.
994.
Mouse polyclonal antisera were raised to the Mr 130,000 and Mr 115,000 cell surface glycoproteins, desmocollins, of desmosomes from bovine nasal epithelium. Immunoblotting confirmed that the antisera were specific for the desmocollins. An immunofluorescence study showed that the antisera distinguished between the basal and suprabasal layers of bovine and human epidermis. The antibodies reacted with cultured keratinocytes only after calcium-induced stratification. In epidermis, therefore, there appears to be a difference between the desmocollins of basal and suprabasal cells that may be important in relation to epidermal differentiation. Previous work has shown that polyclonal antisera raised in other animals (guinea pigs and rabbits) against desmocollins, as well as against other desmosomal components, react with all desmosome-containing epithelia. In contrast, an immunofluorescence survey of bovine, rat, and human tissues showed that the present mouse antisera stained only suprabasal skin cells and the arachnoid layer of the meninges, demonstrating that these have common determinants that distinguished their desmocollins from those of all other tissues. The antibodies also stained 11 of 12 meningiomas and, therefore, may be useful as a marker not only for the diagnosis of these tumors but also for investigation of their histogenesis.  相似文献   
995.
Pharmacosomes--a novel drug delivery system   总被引:2,自引:0,他引:2  
  相似文献   
996.
To ascertain the effect of theophylline on the cardiac chronotropic response to beta-adrenergic stimulation, isoproterenol dose-response curves in healthy young subjects were compared during saline and theophylline maintenance infusions. Each study was repeated 1 to 3 weeks later to evaluate reproducibility. Neither the dose of isoproterenol required to raise the heart rate by 25 bpm (2.32 +/- 0.81 vs. 1.55 +/- 0.46 micrograms on day 1 and 1.28 +/- 0.22 vs. 1.27 +/- 0.25 micrograms on day 2) nor the slopes of the dose-response curves were affected by theophylline. Higher heart rates were observed after isoproterenol bolus dosing during theophylline than during saline infusion because of additive chronotropic effects of theophylline and isoproterenol. Since theophylline does not interact in a synergistic fashion with isoproterenol, phosphodiesterase inhibition appears to be an unlikely mechanism of the chronotropic effect of methylxanthines at therapeutic concentrations.  相似文献   
997.
998.
999.
1000.
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