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   49399篇
  免费   3894篇
  国内免费   108篇
耳鼻咽喉   467篇
儿科学   1842篇
妇产科学   1304篇
基础医学   6191篇
口腔科学   432篇
临床医学   6326篇
内科学   9040篇
皮肤病学   1001篇
神经病学   5026篇
特种医学   1005篇
外科学   5190篇
综合类   413篇
现状与发展   1篇
一般理论   86篇
预防医学   6952篇
眼科学   840篇
药学   3420篇
中国医学   60篇
肿瘤学   3805篇
  2024年   48篇
  2023年   465篇
  2022年   700篇
  2021年   1825篇
  2020年   1115篇
  2019年   1810篇
  2018年   1905篇
  2017年   1463篇
  2016年   1560篇
  2015年   1639篇
  2014年   2309篇
  2013年   3021篇
  2012年   4520篇
  2011年   4452篇
  2010年   2432篇
  2009年   2012篇
  2008年   3469篇
  2007年   3419篇
  2006年   3177篇
  2005年   2979篇
  2004年   2575篇
  2003年   2165篇
  2002年   1886篇
  2001年   241篇
  2000年   160篇
  1999年   238篇
  1998年   310篇
  1997年   223篇
  1996年   179篇
  1995年   162篇
  1994年   118篇
  1993年   101篇
  1992年   82篇
  1991年   70篇
  1990年   63篇
  1989年   58篇
  1988年   43篇
  1987年   36篇
  1986年   37篇
  1985年   34篇
  1984年   42篇
  1983年   40篇
  1982年   17篇
  1981年   22篇
  1980年   23篇
  1978年   20篇
  1977年   15篇
  1976年   15篇
  1975年   16篇
  1973年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Transgenic mice expressing a defined microbial antigen from central nervous system (CNS) cell type-specific promoters can be utilized to investigate the consequences of induction of peripheral immune responses to foreign antigens produced by different CNS cell types. Immunization of mice expressing β-galactosidase (β-gal) in astrocytes with this protein resulted in antigen-dependent infiltration of the CNS by mononuclear cells, principally CD4+ T lymphocytes and monocyte/macrophages. The perivascular and intraparenchymal infiltrates, which were located predominantly in the hippocampal formation and cerebellum, the areas of highest β-gal expression, were associated with astrocytosis, microgliosis, and a generalized increase in blood-brain barrier permeability. The resemblance of these pathological changes to aspects of human immune inflammatory CNS disorders e.g. multiple sclerosis, suggests that an initiating step in the process by which such complex diseases are produced could be the induction of peripheral immune responses to antigens expressed in astrocytes.  相似文献   
83.
Summary A semi-quantitative procedure is described for measuring cell viability after short-term exposure to a test substance using a monolayer culture. Test substances are placed in direct contact with cell monolayers for various time intervals. The substances are removed and the monolayers are incubated in the presence of fluorescein diacetate. Monolayers are viewed under a fluorescent microscope and the percentage of fluorescing (viable) cells is estimated. The method is suitable for examining cytotoxic effects at short times of exposure and for discriminating between test substances that give similar, low toxicity endpoints in standard 24-h assays.  相似文献   
84.
Restructuring in health care does not have to compromise the pursuit of clinical excellence and quality patient care. The clinical advancement program (CAP) at the Hospital for Special Care is a newly developed multidisciplinary reward and recognition program for clinical staff. The program is integrated into the hospital's structure of service line management and, unlike traditional advancement programs, is open to all levels of care providers: professional personnel, technical staff, and aides. This article describes the basic features of the CAP model and how it was developed by a multidisciplinary task force.  相似文献   
85.
86.
87.
88.
89.
OBJECTIVE: To evaluate parents' fruit and vegetable intake and their use of pressure to eat in child feeding as predictors of their 5-year-old daughters' fruit and vegetable, micronutrient, and fat intakes. SUBJECTS: Data were obtained from 191 non-Hispanic white families with 5-year-old girls. DESIGN: Parent data included reports of pressure in child feeding and their own fruit and vegetable intake. Girls' intakes of fruits and vegetables, selected micronutrients, and fat were the main outcomes of interest. STATISTICAL ANALYSIS: Structural equation modeling was used to test a model describing relationships among parents' fruit and vegetable intake, parents' use of pressure in child feeding, and daughters' fruit and vegetable, micronutrient, and fat intakes. RESULTS: The model provided a good fit to the data, revealing that girls' fruit and vegetable intake was positively related to their parents' reported fruit and vegetable intake. Parents who consumed fewer fruits and vegetables tended to report greater pressure in child feeding and had daughters who consumed fewer fruits and vegetables. Girls' reported fruit and vegetable intakes were positively related to their micronutrient intakes and negatively associated with fat intake. APPLICATIONS/CONCLUSIONS: This research demonstrates that parents' own fruit and vegetable intake may encourage fruit and vegetable intake in their daughters, leading to higher micronutrient intakes and lower dietary fat intakes. Conversely, pressure to eat may discourage fruit and vegetable intake among young girls.  相似文献   
90.
采用小猪双侧颈动脉结扎伴失血模型检测双侧颈动脉的结扎伴失血对脑氧分压和O-酪氨酸变化的影响,结果发现小猪脑氧分压为(51±4)托.颈动脉结扎和失血后60min降为(10±1.5)托(P<0.001),当颈动脉恢复通畅和失血再灌注后,脑氧分压增至(40±6)托,此值与预试验时的脑氧分压无明显差异.对照组中脑纹状体中的O-酪氨酸的含量为(0.57±0.19)nmoles/g组织.缺血试验后1h其含量明显升为(29±0.5)nmoles/g组织(P<0.005),显示缺血后再灌注导致脑纹状体O-酪氨酸显著上升.提示组织中羟基产生增加,可能与新生小猪脑缺血和再灌注损伤有一定作用.  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