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   2811篇
  免费   263篇
  国内免费   12篇
耳鼻咽喉   25篇
儿科学   91篇
妇产科学   49篇
基础医学   453篇
口腔科学   36篇
临床医学   301篇
内科学   535篇
皮肤病学   56篇
神经病学   160篇
特种医学   171篇
外科学   345篇
综合类   172篇
一般理论   2篇
预防医学   392篇
眼科学   31篇
药学   134篇
肿瘤学   133篇
  2021年   48篇
  2020年   24篇
  2019年   29篇
  2018年   45篇
  2017年   28篇
  2016年   37篇
  2015年   52篇
  2014年   65篇
  2013年   96篇
  2012年   116篇
  2011年   98篇
  2010年   62篇
  2009年   87篇
  2008年   120篇
  2007年   119篇
  2006年   117篇
  2005年   95篇
  2004年   96篇
  2003年   102篇
  2002年   96篇
  2001年   93篇
  2000年   108篇
  1999年   89篇
  1998年   69篇
  1997年   62篇
  1996年   82篇
  1995年   36篇
  1994年   51篇
  1993年   33篇
  1992年   63篇
  1991年   70篇
  1990年   54篇
  1989年   62篇
  1988年   68篇
  1987年   61篇
  1986年   45篇
  1985年   53篇
  1984年   31篇
  1983年   27篇
  1981年   21篇
  1980年   20篇
  1979年   32篇
  1977年   28篇
  1976年   25篇
  1975年   26篇
  1974年   19篇
  1972年   22篇
  1971年   24篇
  1970年   21篇
  1969年   21篇
排序方式: 共有3086条查询结果,搜索用时 15 毫秒
21.
22.
When a time-limited day treatment program was reconfigured to serve individuals with long-standing psychotic disorders, the number of treatment episodes exceeding six months rose to 70%. To justify this concentration of resources, the program needed methods to identify individuals for whom sustained treatment was appropriate. This report describes development of utilization review methods adapted to publicly funded day treatment of individuals with serious mental illness and training of clinicians in new documentation skills. Data from three years of operation suggest that symptom severity is not a reliable indicator of medical necessity in day treatment. As expected with a clinically based system, a composite measure of benefit and medical necessity indicators weighted toward functioning in living, learning, working, and socializing environments predicted physician reviewer denial of continued day treatment, but length of stay did not.  相似文献   
23.
Screening methods for thyroid hormone disruptors   总被引:15,自引:0,他引:15  
The U.S. Congress has passed legislation requiring the EPA to implement screening tests for identifying endocrine-disrupting chemicals. A series of workshops was sponsored by the EPA, the Chemical Manufacturers Association, and the World Wildlife Fund; one workshop focused on screens for chemicals that alter thyroid hormone function and homeostasis. Participants at this meeting identified and examined methods to detect alterations in thyroid hormone synthesis, transport, and catabolism. In addition, some methods to detect chemicals that bind to the thyroid hormone receptors acting as either agonists or antagonists were also identified. Screening methods used in mammals as well as other vertebrate classes were examined. There was a general consensus that all known chemicals which interfere with thyroid hormone function and homeostasis act by either inhibiting synthesis, altering serum transport proteins, or by increasing catabolism of thyroid hormones. There are no direct data to support the assertion that certain environmental chemicals bind and activate the thyroid hormone receptors; further research is indicated. In light of this, screening methods should reflect known mechanisms of action. Most methods examined, albeit useful for mechanistic studies, were thought to be too specific and therefore would not be applicable for broad-based screening. Determination of serum thyroid hormone concentrations following chemical exposure in rodents was thought to be a reasonable initial screen. Concurrent histologic evaluation of the thyroid would strengthen this screen. Similar methods in teleosts may be useful as screens, but would require indicators of tissue production of thyroid hormones. The use of tadpole metamorphosis as a screen may also be useful; however, this method requires validation and standardization prior to use as a broad-based screen.  相似文献   
24.
25.
26.
27.
28.
BACKGROUND CONTEXT: The publication of several recent studies showing minimal benefit for radiofrequency (RF) lumbar zygapophysial (l-z) joint denervation have led many investigators to reevaluate selection criteria. One controversial explanation for these findings is that the most commonly used cutoff value for selecting patients for l-z (facet) joint RF denervation, greater than 50% pain relief after diagnostic blocks, is too low and hence responsible for the high failure rate. PURPOSE: To compare l-z joint RF denervation success rates between the conventional greater than or equal to 50% pain relief threshold and the more stringently proposed greater than or equal to 80% cutoff for diagnostic medial branch blocks (MBB). STUDY DESIGN/SETTING: Multicenter, retrospective clinical data analysis. PATIENT SAMPLE: Two hundred and sixty-two patients with chronic low back pain who underwent l-z RF denervation at three pain clinics. OUTCOME MEASURES: Outcome measures were greater than 50% pain relief based on visual analog scale or numerical pain rating score after RF denervation persisting at least 6 months postprocedure, and global perceived effect (GPE), which considered pain relief, satisfaction and functional improvement. METHODS: Data were garnered at three centers on 262 patients who underwent l-z RF denervation after obtaining greater than or equal to 50% pain relief after diagnostic MBB. Subjects were separated into those who received partial (greater than or equal to 50% but less than 80%) and near-complete (greater than or equal to 80%) pain relief from the MBB. Outcomes between groups were compared with multivariate analysis after controlling for 14 demographic and clinical variables. RESULTS: One hundred and forty-five patients obtained greater than or equal to 50% but less than 80% pain relief after diagnostic MBB, and 117 patients obtained greater than or equal to 80% relief. In the greater than or equal to 50% group, success rates were 52% and 67% based on pain relief and GPE, respectively. Among patients who experienced greater than 80% relief from diagnostic blocks, 56% obtained greater than or equal to 50% relief from RF denervation and 66% had a positive GPE. CONCLUSIONS: Using more stringent pain relief criteria when selecting patients for l-z joint RF denervation is unlikely to improve success rates, and may lead to misdiagnosis and withholding a potentially valuable treatment from good candidates.  相似文献   
29.
30.
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