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   4357176篇
  免费   338432篇
  国内免费   14719篇
耳鼻咽喉   60291篇
儿科学   139395篇
妇产科学   114197篇
基础医学   666474篇
口腔科学   117993篇
临床医学   396877篇
内科学   790141篇
皮肤病学   107712篇
神经病学   368187篇
特种医学   169430篇
外国民族医学   753篇
外科学   655995篇
综合类   121270篇
现状与发展   24篇
一般理论   2614篇
预防医学   360276篇
眼科学   100873篇
药学   307510篇
  26篇
中国医学   11934篇
肿瘤学   218355篇
  2021年   56140篇
  2020年   35799篇
  2019年   58781篇
  2018年   74346篇
  2017年   56965篇
  2016年   63076篇
  2015年   76041篇
  2014年   110240篇
  2013年   175763篇
  2012年   124147篇
  2011年   128867篇
  2010年   125828篇
  2009年   127562篇
  2008年   115088篇
  2007年   122355篇
  2006年   131177篇
  2005年   125267篇
  2004年   126576篇
  2003年   116785篇
  2002年   106038篇
  2001年   166931篇
  2000年   162009篇
  1999年   148658篇
  1998年   71656篇
  1997年   67603篇
  1996年   65621篇
  1995年   61041篇
  1994年   54965篇
  1993年   51009篇
  1992年   106613篇
  1991年   101377篇
  1990年   97237篇
  1989年   94814篇
  1988年   87137篇
  1987年   85304篇
  1986年   80192篇
  1985年   78348篇
  1984年   65393篇
  1983年   58195篇
  1982年   47187篇
  1981年   43855篇
  1980年   41072篇
  1979年   55100篇
  1978年   44752篇
  1977年   39978篇
  1976年   36836篇
  1975年   36804篇
  1974年   39608篇
  1973年   37749篇
  1972年   35358篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
132.
133.
134.
135.
136.
137.
138.
Advancement in microelectromechanical system has facilitated the microfabrication of polymeric substrates and the development of the novel class of controlled drug delivery devices. These vehicles have specifically tailored three dimensional physical and chemical features which together, provide the capacity to target cell, stimulate unidirectional controlled release of therapeutics and augment permeation across the barriers. Apart from drug delivery devices microfabrication technology’s offer exciting prospects to generate biomimetic gastrointestinal tract models. BioMEMS are capable of analysing biochemical liquid sample like solution of metabolites, macromolecules, proteins, nucleic acid, cells and viruses. This review summarized multidisciplinary application of biomedical microelectromechanical systems in drug delivery and its potential in analytical procedures.  相似文献   
139.
Children who expect they can bring about good outcomes and avoid bad outcomes tend to experience more personal successes. Little is known about factors that contribute to these ‘control expectancies’. The purpose of the present study was to determine whether children's internal control expectancies occur in the context of parents’ internal control expectancies, low family strain, and high family cohesiveness and whether these factors are more strongly related to daughters’ than sons’ control expectancies. A community sample of 85 children aged 9–11 years and their parents (85 mothers; 63 fathers) completed rating scales. Fathers’ more internal control expectancies and mothers’ reports of fewer family strains were associated with daughters’ but not sons’ greater internal control expectancies, and greater family cohesiveness was related to both daughters’ and sons’ internal control orientations. These findings suggest that family factors may contribute to children's, particularly daughters’, development of internal control expectancies.  相似文献   
140.
Objective: Polyunsaturated fatty acids n-3 (PUFA n-3) have shown effects in reducing tumor growth, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) abundantly present in fish oil (FO). When these fatty acids are provided in the diet, they alter the functions of the cells, particularly in tumor and immune cells. However, the effects of α-linolenic fatty acid (ALA), which is the precursor of EPA and DHA, are controversial. Thus, our objective was to test the effect of this parental fatty acid. Methods: Non-tumor-bearing and tumor-bearing Wistar rats (70 days) were supplemented with 1 g/kg body weight of FO or Oro Inca® (OI) oil (rich in ALA). Immune cells function, proliferation, cytokine production, and subpopulation profile were evaluated. Results: We have shown that innate immune cells enhanced phagocytosis capacity, and increased processing and elimination of antigens. Moreover, there was a decrease in production of pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6)) by macrophages. Lymphocytes showed decreased proliferation capacity, increased cluster of differentiation 8 (CD8+) subpopulation, and increased TNF-α production. Conclusions: Oil rich in ALA caused similar immune modulation in cancer when compared with FO.  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