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   184410篇
  免费   1641篇
  国内免费   37篇
耳鼻咽喉   1244篇
儿科学   6882篇
妇产科学   3115篇
基础医学   17691篇
口腔科学   1889篇
临床医学   13101篇
内科学   33229篇
皮肤病学   1051篇
神经病学   17300篇
特种医学   9129篇
外科学   30030篇
综合类   2356篇
一般理论   4篇
预防医学   18713篇
眼科学   3017篇
药学   9859篇
中国医学   644篇
肿瘤学   16834篇
  2023年   140篇
  2022年   219篇
  2021年   502篇
  2020年   258篇
  2019年   405篇
  2018年   22320篇
  2017年   17565篇
  2016年   19749篇
  2015年   1236篇
  2014年   1225篇
  2013年   1299篇
  2012年   7733篇
  2011年   21768篇
  2010年   19157篇
  2009年   11838篇
  2008年   20037篇
  2007年   22196篇
  2006年   1077篇
  2005年   2601篇
  2004年   3736篇
  2003年   4645篇
  2002年   2794篇
  2001年   344篇
  2000年   474篇
  1999年   229篇
  1998年   245篇
  1997年   264篇
  1996年   142篇
  1995年   144篇
  1994年   124篇
  1993年   76篇
  1992年   74篇
  1991年   118篇
  1990年   153篇
  1989年   105篇
  1988年   76篇
  1987年   52篇
  1986年   45篇
  1985年   44篇
  1984年   46篇
  1983年   33篇
  1982年   44篇
  1980年   59篇
  1974年   36篇
  1969年   30篇
  1938年   62篇
  1937年   30篇
  1934年   30篇
  1932年   59篇
  1930年   49篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
11.
12.
Advancing nanomedicines from concept to clinic requires integration of new science with traditional pharmaceutical development. The medical and commercial success of nanomedicines is greatly facilitated when those charged with developing nanomedicines are cognizant of the unique opportunities and technical challenges that these products present. These individuals must also be knowledgeable about the processes of clinical and product development, including regulatory considerations, to maximize the odds for successful product registration. This article outlines these topics with a goal to accelerate the combination of academic innovation with collaborative industrial scientists who understand pharmaceutical development and regulatory approval requirements—only together can they realize the full potential of nanomedicines for patients.  相似文献   
13.
14.
While peer support has been investigated in multiple clinical contexts, its application to the postpartum setting is unknown. The aim was to assess acceptability of a postpartum peer support program for women with diabetes. Observational survey-based needs assessment of forty low-income women with diabetes, receiving care at a major medical institution. Mean age and gravidity were 30.7 years and 3.15 ± 1.67 respectively. 45 % expressed interest in a “buddy.” There was no significant difference between groups desiring and not desiring this program. A majority of respondents desired telephone, text messaging, and in-person contacts (79.2, 72.1, 83.8 %), with 72.5 % of patients desiring diabetes-related activities during clinic waiting time. Many women desire a postpartum diabetes reciprocal peer program for support outside of clinician visits. Patients are receptive to educational services during their wait and outside of clinic time, a potentially valuable opportunity to share important health information.  相似文献   
15.
16.
17.
18.
19.
20.
Dehydrogenase activity is frequently used to assess the general condition of microorganisms in soil and activated sludge. Many studies have investigated the inhibition of dehydrogenase activity by various compounds, including heavy metal ions. However, the time after which the measurements are carried out is often chosen arbitrarily. Thus, it can be difficult to estimate how the toxic effects of compounds vary during the reaction and when the maximum of the effect would be reached. Hence, the aim of this study was to create simple and useful mathematical model describing changes in dehydrogenase activity during exposure to substances that inactivate enzymes. Our model is based on the Lagergrens pseudo-first-order equation, the rate of chemical reactions, enzyme activity, and inactivation and was created to describe short-term changes in dehydrogenase activity. The main assumption of our model is that toxic substances cause irreversible inactivation of enzyme units. The model is able to predict the maximum direct toxic effect (MDTE) and the time to reach this maximum (TMDTE). In order to validate our model, we present two examples: inactivation of dehydrogenase in microorganisms in soil and activated sludge. The model was applied successfully for cadmium and copper ions. Our results indicate that the predicted MDTE and TMDTE are more appropriate than EC50 and IC50 for toxicity assessments, except for long exposure times.  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