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   21947篇
  免费   1105篇
  国内免费   118篇
耳鼻咽喉   224篇
儿科学   395篇
妇产科学   469篇
基础医学   2751篇
口腔科学   1033篇
临床医学   1582篇
内科学   5915篇
皮肤病学   635篇
神经病学   1735篇
特种医学   380篇
外科学   3260篇
综合类   114篇
一般理论   4篇
预防医学   1780篇
眼科学   443篇
药学   1268篇
中国医学   100篇
肿瘤学   1082篇
  2024年   14篇
  2023年   160篇
  2022年   373篇
  2021年   814篇
  2020年   444篇
  2019年   702篇
  2018年   864篇
  2017年   510篇
  2016年   473篇
  2015年   666篇
  2014年   948篇
  2013年   1145篇
  2012年   1759篇
  2011年   1899篇
  2010年   998篇
  2009年   933篇
  2008年   1425篇
  2007年   1527篇
  2006年   1427篇
  2005年   1307篇
  2004年   1160篇
  2003年   997篇
  2002年   974篇
  2001年   124篇
  2000年   119篇
  1999年   118篇
  1998年   159篇
  1997年   150篇
  1996年   109篇
  1995年   83篇
  1994年   69篇
  1993年   78篇
  1992年   58篇
  1991年   57篇
  1990年   45篇
  1989年   32篇
  1988年   25篇
  1987年   23篇
  1986年   29篇
  1985年   32篇
  1984年   34篇
  1983年   28篇
  1982年   34篇
  1981年   41篇
  1980年   21篇
  1979年   24篇
  1978年   16篇
  1976年   12篇
  1975年   12篇
  1974年   15篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
In this study, we analyzed the spatiotemporal expression patterns of the high-molecular weight (MAP2a and b) and low-molecular weight (MAP2c and d) cytoskeletal microtubule-associated protein-2 (MAP2) isoforms with Western blotting, and the cellular localization of the high-molecular weight MAP2 isoforms with immunocytochemistry in the hippocampi of 1- to 21-day-old rats. Moreover, the temporal profile (from 30 min to 1 week) of MAP2 isoform reactivity to kainic acid-induced status epilepticus was studied in P9 rats. During development, the expression of the high-molecular weight MAP2 isoforms significantly increased, while the low-molecular weight isoforms decreased, the most prominent changes occurring during the second postnatal week. This developmental increase in the high-molecular weight MAP2 expression was also confirmed with immunocytochemistry, which showed increased immunoreactivity, particularly in the molecular layers of the dentate gyrus, and in CA1 and CA3 stratum radiatum. In 9-day-old rats, status epilepticus resulted in a rapid transient increase (about 210%) in the high-molecular weight MAP2 expression, without any effect on the low-molecular weight MAP2. Moreover, disturbed dendritic structure in the CA1 and CA3 stratum radiatum was manifested as formation of varicosities 3h after the kainic acid treatment. The strictly developmentally regulated MAP2 isoform expression suggests different functional roles for these proteins during the postnatal development in the rat hippocampus. Moreover, high-molecular weight MAP2s may play a role in nerve cell survival during cell stress.  相似文献   
22.
New methods for simplified quantitation of effector-target conjugation have been developed. The binding unit (BU) is defined as the number of target cells required to bind a specified percentage of effector cells. The number of binding units is determined from binding isotherms in which effector conjugate frequencies are measured by holding constant the number of effector cells and by varying the number of target cells. Alternately, a binding unit can be defined as the number of effector cells required to bind a specified percentage of target cells. In this case, BU is computed from binding isotherms in which target conjugate frequencies are measured at different values of effector cells by holding constant the number of target cells. Also, the area under the curve (AUI) of these isotherms is another index that can be used as an overall measure of the binding capacity in an effector-target system. The experimental values of BU and AUI determined from effector and target isotherms agree well with theoretical predictions based on our previously developed binding model (J. Immunol. Methods (1992) 155, 133–147). The relationship between BU and AUI, and procedures to determine these parameters are shown. The value of these indices to express effector-target conjugation quantitatively has been confirmed by determining the values of BU and AUI for the NK-K562 effector-target system.  相似文献   
23.
Background: Reduction in salivary secretion is the hallmark of Sjögren's syndrome (SS). Calmodulin (CaM) and calmodulin binding proteins (CaMBPs) play a key role in the secretory process of saliva. Recent studies have suggested that SS‐B, an autoantibody associated with SS, is a CaMBP. This finding suggests that CaMBP may contribute to the loss of saliva in SS. To better understand the role(s) of these proteins in SS, the purpose of this study was to compare salivary CaMBPs in Sjögren's patients and controls. Methods: Saliva samples were collected from 20 patients and 20 age‐, race‐, and gender‐matched controls. CaM overlay was used to identify CaMBPs in saliva of patients and controls. Results: Higher number of salivary CaMBPs was observed among patients than controls. Conclusions: The increased number of salivary CaMBPs in SS may suggest a potential role for these proteins in the pathogenesis of the disease.  相似文献   
24.
25.
26.
27.
28.
29.
The minimax linear quadratic problem, where ‘max’ is taken over a finite set of indices (models) and ‘min’ is taken over the set of admissible controls, is considered. The solution is obtained by the robust optimal control application. The control turns out to be a linear combination of the controls optimal for each individual model. This paper develops a numerical method for the optimal weights adjustment. An example shows a quick convergence of the proposed procedure. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
30.
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