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   129408篇
  免费   7823篇
  国内免费   1096篇
耳鼻咽喉   1989篇
儿科学   1973篇
妇产科学   1933篇
基础医学   20708篇
口腔科学   3138篇
临床医学   12322篇
内科学   23176篇
皮肤病学   4047篇
神经病学   10518篇
特种医学   7294篇
外科学   16863篇
综合类   571篇
现状与发展   3篇
一般理论   31篇
预防医学   7021篇
眼科学   3212篇
药学   11593篇
中国医学   1461篇
肿瘤学   10474篇
  2023年   910篇
  2022年   2740篇
  2021年   4451篇
  2020年   2144篇
  2019年   2992篇
  2018年   3737篇
  2017年   3029篇
  2016年   3969篇
  2015年   5491篇
  2014年   6533篇
  2013年   7632篇
  2012年   11455篇
  2011年   10975篇
  2010年   6287篇
  2009年   5385篇
  2008年   7703篇
  2007年   7331篇
  2006年   6628篇
  2005年   6167篇
  2004年   5381篇
  2003年   4688篇
  2002年   4046篇
  2001年   3054篇
  2000年   2801篇
  1999年   2168篇
  1998年   942篇
  1997年   695篇
  1996年   544篇
  1995年   487篇
  1994年   408篇
  1993年   352篇
  1992年   781篇
  1991年   708篇
  1990年   661篇
  1989年   571篇
  1988年   479篇
  1987年   482篇
  1986年   349篇
  1985年   383篇
  1984年   276篇
  1983年   209篇
  1982年   147篇
  1981年   185篇
  1980年   138篇
  1979年   233篇
  1978年   186篇
  1977年   140篇
  1976年   152篇
  1974年   152篇
  1973年   135篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Peacekeeping missions involve experiences that may impact the mental health of participating soldiers. However, research on the long-term mental health consequences of peacekeeping is sparse. The present study aimed to find the prevalence of mental health problems (MHPs), possible MHP predictors, and associations between predictors and MHPs in Norwegian peacekeepers 18–38 years after deployment to a United Nations peacekeeping mission. We used data from a cross-sectional, postdeployment survey of Norwegian peacekeepers who served in Lebanon between 1978 and 1998 (N = 10,605). Participants were assessed for posttraumatic stress disorder (PTSD); anxiety; depression; insomnia; alcohol misuse; drug misuse; and exposure to pre-, peri-, and postdeployment stressors. Logistic regressions were executed to explore key variables associated with MHPs. Total MHP prevalence was 15.1%, 95% CI [14.4, 15.8]. The estimates for specific disorders were 0.1% for drug misuse, 3.4% for alcohol misuse, 4.0% for depression, 6.2% for PTSD, 6.4% for anxiety, and 9.3% for insomnia. Postdeployment stressors, OR = 1.91, 95% CI [1.79, 2.04]; employment status, OR = 1.41, 95% CI [1.33, 1.48]; and traumatic exposure during deployment, OR = 1.11, 95% CI [1.09, 1.12], were positively related to PTSD, χ2(17, N = 8,568) = 1,791.299, p < .001. Similar patterns were found for the other MHPs. Considering that most participants (84.9%) reported low symptom levels, our findings challenge the widespread public perception that most peacekeepers have MHPs. Moreover, our results indicate that future peacekeepers should be prepared for challenges they may face not only during deployment but also in the years following their homecoming.  相似文献   
73.
74.
Objective: This study investigated the effect of regular swimming exercise according to the duration-intensity on neurocognitive function in a cerebral infarction rat model.

Methods: Forty male Sprague–Dawley 10-week-old rats, weighing 300 ± 50 g, were subjected to photothrombotic cerebral infarction. The remaining 36 rats were randomly divided into four groups (n = 9 per group: non-exercise (group A); swimming exercise of short duration-intensity (5 min/day, group B); swimming exercise of moderate duration-intensity (10 min/day, group C); and swimming exercise of long duration-intensity (20 min/day, group D). Exercise was performed five times a week for 4 weeks, beginning the day after cerebral infarction. Neurocognitive function was evaluated with the Morris water maze test. Immunohistochemistry and western blot analysis examined brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) at 4 weeks postinfarction.

Results: At 4 weeks postinfarction, escape latency was found to be shorter in group C than in any of groups A, B, or D. Immunohistochemistry revealed the most significant immunoreactivity for BDNF and VEGF in group C. Western blot analysis demonstrated that BDNF and VEGF proteins were markedly expressed in group C.

Conclusions: Regular swimming exercise of moderate duration-intensity may be the most effective exercise protocol for the recovery of neurocognitive function in cerebral infarction rat model.  相似文献   

75.
Young children enter kindergarten with varying levels of readiness and abilities to learn. One factor that contributes to lower levels of school readiness is poverty. One timely, cost-effective, and feasible strategy to boost school readiness, regardless of exposure to high-quality preschool is to leverage the summer months prior to kindergarten entry and provide comprehensive, evidence-based programming immediately before the school year begins. The current study implemented a community-based summer programme targeted at improving school readiness for 25 four- and five-year-old children in a low-income community. Across the 9-week study, children participated in two types of early literacy activities and the Incredible Years social/emotional learning curriculum. Results indicate that participants demonstrated significant growth across three early literacy skills and were rated as overall stable regarding their behaviour across the summer. These results are discussed along with implications and future directions in this line of research.  相似文献   
76.
77.
78.
79.
80.
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