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   3314篇
  免费   249篇
  国内免费   15篇
耳鼻咽喉   45篇
儿科学   103篇
妇产科学   50篇
基础医学   449篇
口腔科学   37篇
临床医学   347篇
内科学   553篇
皮肤病学   45篇
神经病学   176篇
特种医学   253篇
外科学   386篇
综合类   66篇
一般理论   6篇
预防医学   349篇
眼科学   145篇
药学   211篇
中国医学   1篇
肿瘤学   356篇
  2021年   34篇
  2020年   20篇
  2019年   33篇
  2018年   39篇
  2017年   26篇
  2016年   29篇
  2015年   51篇
  2014年   74篇
  2013年   136篇
  2012年   150篇
  2011年   135篇
  2010年   100篇
  2009年   86篇
  2008年   129篇
  2007年   189篇
  2006年   147篇
  2005年   162篇
  2004年   151篇
  2003年   186篇
  2002年   141篇
  2001年   65篇
  2000年   33篇
  1999年   71篇
  1998年   68篇
  1997年   81篇
  1996年   68篇
  1995年   65篇
  1994年   41篇
  1993年   48篇
  1992年   60篇
  1991年   52篇
  1990年   52篇
  1989年   48篇
  1988年   50篇
  1987年   54篇
  1986年   42篇
  1985年   37篇
  1984年   34篇
  1983年   36篇
  1982年   43篇
  1981年   31篇
  1980年   52篇
  1979年   22篇
  1978年   28篇
  1977年   34篇
  1976年   31篇
  1975年   27篇
  1974年   24篇
  1973年   21篇
  1970年   16篇
排序方式: 共有3578条查询结果,搜索用时 31 毫秒
1.
Owing to large differences in the incidence of AIDS (acquired immunodeficiency syndrome) and in public health resources and priorities, the impact of AIDS on state and local health departments has been variable. Nonetheless, health departments everywhere are being held responsible for surveillance and control of the HIV (human immunodeficiency virus) epidemic which we believe requires, at minimum, convenient, free HIV testing and counseling; expanded HIV services in sexually transmitted diseases clinics and substance treatment centers; locally oriented AIDS information/education; notification of persons unknowingly exposed to HIV; restrictive measures for HIV-infected persons who, after counseling, persist in exposing others; regulation or closure of public establishments in which HIV transmission is likely to result; and confidential reporting of all HIV test results to public health departments. In Colorado new legislation was passed to require reporting of HIV test results, to provide the reports with near absolute protections against unauthorized disclosure, and to modify quarantine statues to incorporate rights to due process, appeals, and confidentially. States in which there is a legal basis for discrimination against gay men will need to rectify this problem first. There is no evidence that reporting of HIV infections in Colorado has adversely affected the rate at which persons with HIV risk behaviors volunteer to be tested. For Denver and Colorado Departments of Health, more than 70 per cent of the estimated $2,796,000 expended in AIDS activities during 1987 was federal.  相似文献   
2.
3.
4.
Background: Developmental differences in short- and long-term responses to pain, especially surgical pain, have received minimal attention. The purpose of the present study was to examine postoperative responses in rats of developmental ages paralleling the infant to young adult human.

Methods: The withdrawal threshold to von Frey filament testing and withdrawal latency to hind-paw radiant heating were determined before and for various times after hind-paw incision in rats 2, 4, and 16 weeks of age. Control rats of these ages were observed serially without surgery.

Results: In control animals, younger rats were more sensitive to mechanical stimulation and less sensitive to thermal stimulation. Paw incision resulted in similar changes to both types of stimulation in all age groups, peaking 4 h after surgery. However, the return to normal sensitivity to mechanical stimulation, as measured by return of threshold to 80% of normal, occurred more quickly in 2-week-old than in 4- and 16-week-old animals. In contrast, there was no age difference for time to return to normal sensitivity to thermal stimulation after surgery.  相似文献   

5.
6.
The phospholipid-hydrolyzing enzyme phospholipase A2 (PLA2) (EC 3.1.1.4) exists in several forms which can be located in the cytosol or on cellular membranes. We review briefly cellular regulatory mechanisms involving covalent modification by protein kinase C and the action of Ca2+, cytokines, G proteins and other cellular proteins. The major focus is the role of phospholipid structure on PLA2 activity, including (1) the mechanism of PLA2 action on synthetic phospholipid bilayers, (2) perturbation of synthetic and cellular membranes with lipophilic agents and membrane-interactive peptides and (3) the ability of these agents to activate endogenous PLA2 activity, with emphasis on the venom and plant toxins melittin, cardiotoxin and Pyrularia thionein.  相似文献   
7.
Bottomley  PA; Lee  Y; Weiss  RG 《Radiology》1997,204(2):403
  相似文献   
8.
A Vernon  M H Hoagland  E J Perlman 《JAMA》1987,258(15):2063-2064
  相似文献   
9.
The drive for quality assurance in general dental practice has arisen as a response to changing standards and demands. Dentists need to develop skills in change management in this new culture of change. Groups of practitioners often encounter difficulties when managing change, yet it is essential that they lead the process. Such problems are common among groups of professionals. A wide range of topics is presented that may, from one point of view, represent challenging or problem areas (obstacles) for a group practice but may also, from a different point of view, provide a framework of opportunities for improvement, and facilitate the management processes within the practice and the management of change in particular (tools). The range of skills required to assist a professional group is such that individual dentists or advisers may not be able to achieve much on their own. The best way forward may be to interpret the problems as a professional training need and to organise training as a group. These issues will be considered under the following headings: partners and teams; introduction: the need for change management; the challenge for group practices; obstacles and tools; conclusion: the way forward--a case for training.  相似文献   
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