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   1693篇
  免费   118篇
  国内免费   28篇
耳鼻咽喉   1篇
儿科学   63篇
妇产科学   12篇
基础医学   169篇
口腔科学   51篇
临床医学   171篇
内科学   218篇
皮肤病学   15篇
神经病学   288篇
特种医学   266篇
外科学   76篇
综合类   21篇
预防医学   64篇
眼科学   8篇
药学   350篇
肿瘤学   66篇
  2022年   5篇
  2021年   11篇
  2020年   4篇
  2019年   12篇
  2018年   21篇
  2017年   10篇
  2016年   21篇
  2015年   29篇
  2014年   37篇
  2013年   36篇
  2012年   54篇
  2011年   48篇
  2010年   58篇
  2009年   40篇
  2008年   52篇
  2007年   70篇
  2006年   61篇
  2005年   63篇
  2004年   46篇
  2003年   48篇
  2002年   39篇
  2001年   40篇
  2000年   42篇
  1999年   33篇
  1998年   64篇
  1997年   75篇
  1996年   87篇
  1995年   58篇
  1994年   44篇
  1993年   49篇
  1992年   45篇
  1991年   43篇
  1990年   47篇
  1989年   64篇
  1988年   73篇
  1987年   51篇
  1986年   49篇
  1985年   38篇
  1984年   24篇
  1983年   16篇
  1982年   19篇
  1981年   13篇
  1980年   16篇
  1979年   9篇
  1978年   8篇
  1977年   14篇
  1976年   11篇
  1975年   6篇
  1974年   8篇
  1945年   6篇
排序方式: 共有1839条查询结果,搜索用时 0 毫秒
1.
2.
3.
We quantitatively investigated the effect of carbidopa/levodopa (25/100) on physical fatigue during finger tapping and force generation in a double-blind, placebo-controlled crossover study. Parkinson's disease (PD) subjects were randomly assigned to carbidopa/levodopa or placebo for Visit 1 or 2 and participated in the following two studies: (1) Finger tapping. Twenty-five PD patients used their index fingers to strike two keys 20 cm apart on a musical instrument digital interface (MIDI) keyboard. The slopes of the regression line of dwell time and movement time were used to assess the rate of fatigue development. (2) Force generation. Twelve PD patients contracted the wrist extensors maximally to obtain a baseline maximum voluntary contraction (BMVC) force. Then they repetitively contracted the wrist extensors at 50% of the BMVC for 7 seconds and rested for 3 seconds. An interval maximum voluntary contraction (IMVC) was measured every three repetitions. Fatigue was defined as an IMVC of less than 60% of the BMVC. The slope of the regression line of IMVC was used to assess the rate of force decline. These two studies were repeated 1 hour after carbidopa/levodopa (25/100) or placebo. Subjects filled out the Multidimensional Fatigue Inventory (MFI) at the beginning of the first visit. Results showed that the slope of dwell time decreased with levodopa but not with placebo (P = 0.004). The rate of force decline also decreased with levodopa but not with placebo (P = 0.01). The subscores in the dimension of physical fatigue in the MFI did not correlate with the rate changes in dwell time or the rate changes in force decline. We concluded that (1) levodopa improves physical fatigue in finger tapping and force generation, (2) physical fatigue in Parkinson's disease is at least partially related to dopamine deficiency, and (3) the MFI measures different aspects of physical fatigue compared with those measured by finger tapping and force generation.  相似文献   
4.
Effect of pregnancy on panic attacks   总被引:1,自引:0,他引:1  
Three women with panic disorder showed marked improvement in their panic symptoms during pregnancy. Such effects might be due to pregnancy's blunting of the sympathoadrenal response to simple physiologic stimuli, effects on barbiturate receptors, or improvement in psychological functioning.  相似文献   
5.
A comprehensive anatomic and radiographic analysis of the peribursal fat plane in 12 cadavers confirmed that the fat plane seen on radiographs represents extrasynovial fat lining the subacromial bursa and documented the anatomic relations of the bursa. A three-part retrospective clinical evaluation of rotator cuff tears, calcific tendinitis, and rheumatoid arthritis was performed. Two osteoradiologists blindly graded the appearance of the peribursal fat plane with the shoulder in external versus internal rotation in 21 patients with arthrographically intact rotator cuffs and 21 patients with disrupted rotator cuffs. The peribursal fat plane was seen better with disrupted rotator cuffs. The peribursal fat plane was seen better with the shoulder in internal rotation and was seen in 60% of control subjects but only 21% of patients with rotator cuff tears. Partial or complete obliteration of this fat plane is a sensitive (79%) but less specific (60%) indicator of rotator cuff tears. Obliteration of the peribursal fat plane by inflammatory processes in adjacent tissues, including calcific tendinitis and rheumatoid arthritis, occurred with a high frequency.  相似文献   
6.
7.
8.
Periosteal Ewing sarcoma   总被引:3,自引:0,他引:3  
  相似文献   
9.
10.
In a prospective, randomized study of insemination with donor semen, intracervical insemination by straw was compared with insemination using a cervical cap with an intracervical reservoir. A total of 91 patients completed 486 treatment cycles. There were no significant differences in age, parity, indication for insemination by donor, or method of cycle monitoring between women who became pregnant and those who did not conceive with either insemination method. In 236 standard intracervical insemination cycles, 14 patients became pregnant (5.9% per cycle), whereas 38 patients conceived in 250 cervical cap cycles (15.2% per cycle). Both the crude pregnancy rates and the cumulative pregnancy rates calculated by the Kaplan-Meier life-table method were significantly different (chi(2)-test, P < 0.001, and log-rank test, P < 0.005 respectively). Pregnancy rates in artificial insemination with cryopreserved donor semen may be improved by the use of a cervical cap when compared to cervical insemination by straw. The use of the cervical cap may prolong the exposure of the spermatozoa to the cervical mucus and prevent the backflow of semen into the vagina.   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