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   1748888篇
  免费   120770篇
  国内免费   4706篇
耳鼻咽喉   22381篇
儿科学   57048篇
妇产科学   46437篇
基础医学   268354篇
口腔科学   46075篇
临床医学   167240篇
内科学   330813篇
皮肤病学   35855篇
神经病学   138264篇
特种医学   63941篇
外国民族医学   418篇
外科学   246335篇
综合类   35309篇
现状与发展   3篇
一般理论   551篇
预防医学   144795篇
眼科学   38849篇
药学   130410篇
  7篇
中国医学   4033篇
肿瘤学   97246篇
  2021年   13912篇
  2019年   14521篇
  2018年   20489篇
  2017年   15308篇
  2016年   16907篇
  2015年   19217篇
  2014年   26279篇
  2013年   40253篇
  2012年   56202篇
  2011年   60237篇
  2010年   34935篇
  2009年   31814篇
  2008年   54958篇
  2007年   58743篇
  2006年   58407篇
  2005年   56202篇
  2004年   53990篇
  2003年   51465篇
  2002年   49850篇
  2001年   77196篇
  2000年   79220篇
  1999年   66245篇
  1998年   18681篇
  1997年   16628篇
  1996年   16473篇
  1995年   15655篇
  1994年   14484篇
  1992年   52447篇
  1991年   52659篇
  1990年   51494篇
  1989年   49275篇
  1988年   45483篇
  1987年   44640篇
  1986年   42316篇
  1985年   40429篇
  1984年   30346篇
  1983年   25842篇
  1982年   15018篇
  1979年   27909篇
  1978年   19872篇
  1977年   16168篇
  1976年   16242篇
  1975年   17466篇
  1974年   20895篇
  1973年   20241篇
  1972年   18743篇
  1971年   17677篇
  1970年   16379篇
  1969年   14965篇
  1968年   14269篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Primary chemotherapy administered to breast cancer patientsis the best model to identify baseline features able to predictwhich patients may be most likely to benefit or not from a cytotoxicregimen. In the March issue of Annals of Oncology two papersevaluated the predictive role of immunohistochemical p53 expressionon  相似文献   
93.
94.
95.
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified.  相似文献   
96.
科学研究的目标是创造和传播知识。这得通过对系统收集以及报告信息的批判性分析来完成。批判性分析始于一个简单的步骤,即在运用复杂统计学分析方法进行比较之前对所收集的数据进行深入检查。根据所收集的数据类型按照标准化方式进行统计学分析。在为解决研究问题而需采用合理、标准化步骤进行比较时,新知识就产生了,同时要避免错误的结论。在对数据进行仔细检查和分析之后,为了保证结论的正确性,再对数据进行一次批判性评论是非常重要的补充步骤。在科学文献中发表研究成果过程中涉及的同行评价对于传播新知识并保证其质量方面是一个非常重要的步骤。如果没有将研究成果发表供同行参考,这项研究就不算完整。  相似文献   
97.
98.
Patients with multiple system atrophy (MSA) present large changes in blood pressure (BP) due to autonomic disturbances. We analyzed how this change may influence dynamic cerebral autoregulation (DCA). Simultaneous recordings of arterial BP (Finapres) and middle cerebral artery (MCA) blood flow velocity (BFV) (transcranial Doppler) were performed in 10 patients with MSA (61 +/- 12 yr of age) and 12 healthy volunteers (61 +/- 11 yr of age): cerebral BFV response to oscillations in mean BP was studied in the supine position by cross-spectral analysis of mean BP and mean MCA BFV. The DCA was also studied during the decrease in BP the first seconds when standing up from a sitting position by the assessment of the cerebrovascular resistance index (CR; mean BP/mean MCA BFV ratio). The MCA BFV/BP cross-spectral analysis showed a phase for the mid-frequency band (0.07-0.2 Hz) significantly larger in MSA, suggesting more active autoregulation in response to larger changes in BP. Changes in CR reflecting the rate of autoregulation, when standing did not differ between the two groups. These data suggest that dynamic cerebral autoregulation is preserved in MSA.  相似文献   
99.
Published data devoted to making and characterization of the properties of polymeric wound dressings with proteolytic action are reviewed. These data are indicative of individual dependence of the physicochemical properties, activity, and stability of each particular enzyme on the type of polymer matrix and the method of immobilization. In order to obtain wound dressings, which are active in physiological medium and retain their activity upon sterilization, it is necessary to optimize the composition and characteristics of a polymer matrix and the enzyme included into its structure. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 8, pp. 24–28, August, 2006.  相似文献   
100.
A Survey of Plants Used as Wild Vegetables in Four Districts of Botswana   总被引:1,自引:0,他引:1  
A survey of plants used as wild vegetables was conducted in four districts of Botswana in August and September 2005. The objective was to determine which wild plants were used as vegetables in the study area, and to document their cooking and preservation methods. Fourteen species representing seven families were mentioned as wild vegetables. In addition, six species from four families had other uses in traditional medicine. The implications of the documented processing methods on the retention of nutrients in the vegetables are discussed.  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