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   10885篇
  免费   1034篇
  国内免费   89篇
耳鼻咽喉   83篇
儿科学   358篇
妇产科学   164篇
基础医学   1596篇
口腔科学   348篇
临床医学   1249篇
内科学   2005篇
皮肤病学   240篇
神经病学   757篇
特种医学   653篇
外科学   1379篇
综合类   255篇
一般理论   4篇
预防医学   988篇
眼科学   195篇
药学   705篇
中国医学   14篇
肿瘤学   1015篇
  2021年   134篇
  2020年   88篇
  2019年   121篇
  2018年   157篇
  2017年   129篇
  2016年   140篇
  2015年   161篇
  2014年   202篇
  2013年   385篇
  2012年   454篇
  2011年   473篇
  2010年   296篇
  2009年   285篇
  2008年   405篇
  2007年   533篇
  2006年   434篇
  2005年   435篇
  2004年   430篇
  2003年   396篇
  2002年   374篇
  2001年   307篇
  2000年   340篇
  1999年   303篇
  1998年   186篇
  1997年   187篇
  1996年   141篇
  1995年   155篇
  1994年   116篇
  1993年   131篇
  1992年   289篇
  1991年   263篇
  1990年   223篇
  1989年   254篇
  1988年   197篇
  1987年   216篇
  1986年   211篇
  1985年   252篇
  1984年   149篇
  1983年   142篇
  1982年   123篇
  1981年   100篇
  1980年   110篇
  1979年   137篇
  1978年   93篇
  1977年   104篇
  1976年   109篇
  1975年   90篇
  1973年   93篇
  1972年   92篇
  1971年   92篇
排序方式: 共有10000条查询结果,搜索用时 484 毫秒
1.

Objective

Successful weight loss interventions for African-Americans adolescents are lacking. Cognitive-behavioral interventions seek to develop weight loss skills (e.g., counting calories, goal setting, managing one's environment). Little is known about how well adolescents implement such skills in their daily lives. Study aims were to (1) examine weight loss skills utilization at midpoint and end of a 6-month cognitive-behavioral/motivational interviewing weight loss sequential multiple assignment randomized trial (SMART), and (2) determine if greater skill utilization predicted weight loss at treatment end and 3 months post-treatment.

Method

One hundred and eighty six African-Americans adolescents with obesity and their caregiver were first randomly assigned to complete 3 months of cognitive-behavioral and motivational interviewing family-based weight loss treatment in their home or in the research office (Phase 1). Nonresponders (i.e., those who lost < 3% of initial weight, n?=?161) were rerandomized to 3 months of continued skills training (n?=?83) or contingency management (n?=?78) for Phase 2; responders were allocated to 3 months of relapse prevention (n?=?20). Adolescents’ frequency of weight loss skills utilization was assessed via questionnaire at treatment midpoint and end.

Results

Higher treatment attendance was associated with better skill utilization. Higher skill utilization was associated with more weight loss at treatment end, whereas higher baseline confidence was associated with more weight loss at follow-up.

Conclusions

This study indicates the importance of attending weight loss intervention sessions to develop and strengthen weight loss skills in African-American adolescents with obesity, and strengthening confidence to use such skills for continued weight loss.  相似文献   
2.
3.
Using data on waterfowl band recoveries, we identified spatially explicit hotspots of concentrated waterfowl movement to predict occurrence and spatial spread of a novel influenza A virus (clade 2.3.4.4) introduced from Asia by waterfowl from an initial outbreak in North America in November 2014. In response to the outbreak, the hotspots of waterfowl movement were used to help guide sampling for clade 2.3.4.4 viruses in waterfowl as an early warning for the US poultry industry during the outbreak . After surveillance sampling of waterfowl, we tested whether there was greater detection of clade 2.3.4.4 viruses inside hotspots. We found that hotspots defined using kernel density estimates of waterfowl band recoveries worked well in predicting areas with higher prevalence of the viruses in waterfowl. This approach exemplifies the value of ecological knowledge in predicting risk to agricultural security.  相似文献   
4.
5.
6.
7.
8.
Objective. The safety and efficacy of intrathecal (IT) ziconotide was studied in a randomized, double‐blind, placebo‐controlled trial. Materials and Methods. Patients (169 ziconotide, 86 placebo) with severe chronic nonmalignant pain unresponsive to conventional therapy and a visual analog scale of pain intensity (VASPI score) ≥ 50 mm were treated over a 6‐day period in an inpatient hospital setting. Initial starting dose was 0.4 µg/hour and was titrated to analgesia or intolerance (maximum dose 7.0 µg/hour). The starting and maximum doses were reduced to 0.1 µg/hour and 2.4 µg/hour, respectively, due to adverse events (AEs). Results. The mean percent reduction in VASPI score from baseline was 31.2% and 6.0% for ziconotide‐ and placebo‐treated patients, respectively (p ≤ 0.001). During the initial titration phase, a significantly greater percentage of patients in the ziconotide group compared to the placebo group reported AEs, including abnormal gait, amblyopia, dizziness, nausea, nystagmus, pain, urinary retention, and vomiting. Conclusion. Ziconotide provided significant analgesia in patients for whom conventional therapy failed. However, there was a considerable incidence of ziconotide‐associated AEs due to the rapid titration and high doses administered.  相似文献   
9.
10.
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