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   19014篇
  免费   1026篇
  国内免费   120篇
耳鼻咽喉   132篇
儿科学   415篇
妇产科学   485篇
基础医学   2771篇
口腔科学   790篇
临床医学   1792篇
内科学   3308篇
皮肤病学   301篇
神经病学   1541篇
特种医学   584篇
外科学   2296篇
综合类   506篇
一般理论   41篇
预防医学   1403篇
眼科学   1075篇
药学   1327篇
  2篇
中国医学   61篇
肿瘤学   1330篇
  2024年   17篇
  2023年   742篇
  2022年   1059篇
  2021年   1089篇
  2020年   1223篇
  2019年   686篇
  2018年   711篇
  2017年   711篇
  2016年   681篇
  2015年   745篇
  2014年   1379篇
  2013年   1043篇
  2012年   852篇
  2011年   755篇
  2010年   897篇
  2009年   852篇
  2008年   613篇
  2007年   617篇
  2006年   582篇
  2005年   559篇
  2004年   475篇
  2003年   440篇
  2002年   403篇
  2001年   358篇
  2000年   293篇
  1999年   351篇
  1998年   183篇
  1997年   158篇
  1996年   154篇
  1995年   144篇
  1994年   103篇
  1993年   82篇
  1992年   229篇
  1991年   222篇
  1990年   252篇
  1989年   166篇
  1988年   144篇
  1987年   67篇
  1986年   26篇
  1985年   32篇
  1984年   31篇
  1983年   12篇
  1982年   11篇
  1981年   10篇
  1908年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
We provide further evidence for the two-factor structure of the 9-item Academic Expectations Stress Inventory (AESI) using confirmatory factor analysis on a sample of 289 Canadian adolescents and 310 Singaporean adolescents. Examination of measurement invariance tests the assumption that the model underlying a set of scores is directly comparable across groups. This study also examined the cross-cultural validity of the AESI using multigroup confirmatory factor analysis across both the Canadian and Singaporean adolescent samples. The results suggested cross-cultural invariance of form, factor loadings, and factor variances and covariances of the AESI across both samples. Evidence of AESI's convergent and discriminant validity was also reported. Findings from t-tests revealed that Singaporean adolescents reported a significantly higher level of academic stress arising from self expectations, other expectations, and overall academic stress, compared to Canadian adolescents. Also, a larger cross-cultural effect was associated with academic stress arising from other expectations compared with academic stress arising from self expectations.  相似文献   
82.
83.
84.
85.
86.
87.
88.
The melt agglomeration process of lactose powder with hydrogenated cottonseed oil (HCO) as the hydrophobic meltable binder was investigated by studying the physicochemical properties of molten HCO modified by sucrose stearates S170, S770 and S1570. The size, size distribution, micromeritic and adhesion properties of agglomerates as well as surface tension, contact angle, viscosity and specific volume of molten HCO, with and without sucrose stearates, were examined. The viscosity, specific volume and surface tension of molten HCO were found to be modified to varying extents by sucrose stearates which are available in different HLB values and melt properties. The growth of melt agglomerates was promoted predominantly by an increase in viscosity, an increase in specific volume or a decrease in surface tension of the molten binding liquid. The agglomerate growth propensity was higher with an increase in inter-particulate binding strength, agglomerate surface wetness and extent of agglomerate consolidation which enhanced the liquid migration from agglomerate core to periphery leading to an increased surface plasticity for coalescence. The inclusion of high concentrations of completely meltable sucrose stearate S170 greatly induced the growth of agglomerates through increased specific volume and viscosity of the molten binding liquid. On the other hand, the inclusion of incompletely meltable sucrose stearates S770 and S1570 promoted the agglomeration mainly via the reduction in surface tension of the molten binding liquid with declining agglomerate growth propensity at high sucrose stearate concentrations. In addition to being an agglomeration modifier, sucrose stearate demonstrated anti-adherent property in melt agglomeration process. The properties of molten HCO and melt agglomerates were dependent on the type and concentration of sucrose stearate added.  相似文献   
89.

Purpose  

Hepatitis B virus (HBV) is endemic in Bangladesh, and the quality of life (QoL) of these patients remains unknown as there is no instrument available in the native language. In this study, we translated the 56-item Hepatitis Quality of Life Questionnaire (HQLQ) into Bengali and evaluated its validity and reliability.  相似文献   
90.
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