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   3338371篇
  免费   235110篇
  国内免费   5923篇
耳鼻咽喉   47618篇
儿科学   105644篇
妇产科学   91934篇
基础医学   485655篇
口腔科学   95088篇
临床医学   297210篇
内科学   641555篇
皮肤病学   74404篇
神经病学   265063篇
特种医学   127203篇
外国民族医学   901篇
外科学   505170篇
综合类   71418篇
现状与发展   16篇
一般理论   1248篇
预防医学   254639篇
眼科学   78977篇
药学   249206篇
  15篇
中国医学   6936篇
肿瘤学   179504篇
  2018年   35624篇
  2017年   27294篇
  2016年   30504篇
  2015年   34299篇
  2014年   48457篇
  2013年   72940篇
  2012年   99339篇
  2011年   105622篇
  2010年   62738篇
  2009年   59786篇
  2008年   99651篇
  2007年   106944篇
  2006年   107594篇
  2005年   104500篇
  2004年   100039篇
  2003年   96609篇
  2002年   93935篇
  2001年   150116篇
  2000年   154023篇
  1999年   130130篇
  1998年   37753篇
  1997年   33267篇
  1996年   32920篇
  1995年   31160篇
  1994年   28856篇
  1993年   27181篇
  1992年   101248篇
  1991年   98818篇
  1990年   96629篇
  1989年   93549篇
  1988年   86553篇
  1987年   85043篇
  1986年   80372篇
  1985年   77095篇
  1984年   57426篇
  1983年   48983篇
  1982年   29281篇
  1981年   26430篇
  1979年   53789篇
  1978年   38499篇
  1977年   32666篇
  1976年   30600篇
  1975年   33773篇
  1974年   40304篇
  1973年   38703篇
  1972年   36671篇
  1971年   34584篇
  1970年   32281篇
  1969年   30833篇
  1968年   28544篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
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   
63.
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   
64.
Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.  相似文献   
65.
66.
67.
68.
69.
70.
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