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   188778篇
  免费   2132篇
  国内免费   42篇
耳鼻咽喉   1250篇
儿科学   6969篇
妇产科学   3347篇
基础医学   18478篇
口腔科学   1888篇
临床医学   13787篇
内科学   33565篇
皮肤病学   920篇
神经病学   17482篇
特种医学   9538篇
外国民族医学   17篇
外科学   30516篇
综合类   2438篇
一般理论   7篇
预防医学   19397篇
眼科学   2892篇
药学   10311篇
中国医学   643篇
肿瘤学   17507篇
  2022年   86篇
  2021年   214篇
  2020年   159篇
  2019年   259篇
  2018年   22181篇
  2017年   17537篇
  2016年   19735篇
  2015年   1180篇
  2014年   1151篇
  2013年   1247篇
  2012年   7584篇
  2011年   21594篇
  2010年   19138篇
  2009年   11862篇
  2008年   20041篇
  2007年   22199篇
  2006年   1094篇
  2005年   2716篇
  2004年   3892篇
  2003年   4858篇
  2002年   2955篇
  2001年   761篇
  2000年   943篇
  1999年   637篇
  1998年   386篇
  1997年   356篇
  1996年   235篇
  1995年   225篇
  1994年   205篇
  1993年   169篇
  1992年   392篇
  1991年   388篇
  1990年   415篇
  1989年   326篇
  1988年   317篇
  1987年   262篇
  1986年   276篇
  1985年   259篇
  1984年   205篇
  1983年   192篇
  1982年   120篇
  1981年   93篇
  1980年   138篇
  1979年   153篇
  1978年   119篇
  1977年   98篇
  1975年   90篇
  1974年   124篇
  1973年   117篇
  1971年   86篇
排序方式: 共有10000条查询结果,搜索用时 15 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.
Maternal and Child Health Journal - Background Prenatal substance use screening is recommended. The 4 P’s Plus screener includes questions on perceived problematic substance use in parents...  相似文献   
16.
17.
18.
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   
19.
20.
Contraceptive use is an important strategy for the prevention of unwanted pregnancy and avoidance of induced abortion. Of all the contraception methods, emergency contraceptive (EC) offers the last chance to achieve this. However, few studies have documented the use of EC among young people in Ghana. This study explored knowledge and usage of EC as well as the factors associated with it among University of Cape Coast students. Data were obtained on the knowledge and usage of ECs among University of Cape Coast students in 2013. Logistic regression analysis was used to investigate the association between students’ socio-demographic characteristics and EC knowledge and use. More male students (72 %) than females (59 %) were sexually active. Fifty-seven percent of the respondents had ever heard of EC and 36 % had ever used EC. Although males were more likely to be sexually active, females were more likely to have knowledge of EC use compared to males. The study underscores the need to increase awareness regarding EC among University students in order to offer them the opportunity that EC provides if other forms of contraceptives are missed.  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