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   4263篇
  免费   479篇
  国内免费   2篇
耳鼻咽喉   33篇
儿科学   282篇
妇产科学   77篇
基础医学   564篇
口腔科学   141篇
临床医学   495篇
内科学   957篇
皮肤病学   39篇
神经病学   467篇
特种医学   109篇
外科学   408篇
综合类   96篇
一般理论   6篇
预防医学   464篇
眼科学   57篇
药学   309篇
中国医学   7篇
肿瘤学   233篇
  2021年   66篇
  2020年   40篇
  2019年   51篇
  2018年   79篇
  2017年   61篇
  2016年   49篇
  2015年   76篇
  2014年   68篇
  2013年   136篇
  2012年   198篇
  2011年   193篇
  2010年   104篇
  2009年   106篇
  2008年   187篇
  2007年   179篇
  2006年   170篇
  2005年   180篇
  2004年   175篇
  2003年   165篇
  2002年   173篇
  2001年   123篇
  2000年   91篇
  1999年   113篇
  1998年   49篇
  1997年   55篇
  1996年   35篇
  1995年   40篇
  1993年   44篇
  1992年   81篇
  1991年   103篇
  1990年   76篇
  1989年   83篇
  1988年   87篇
  1987年   97篇
  1986年   81篇
  1985年   81篇
  1984年   63篇
  1983年   59篇
  1982年   48篇
  1980年   49篇
  1979年   75篇
  1978年   58篇
  1977年   52篇
  1976年   38篇
  1975年   43篇
  1974年   51篇
  1973年   44篇
  1972年   38篇
  1970年   39篇
  1969年   41篇
排序方式: 共有4744条查询结果,搜索用时 31 毫秒
1.
The cephalometric measurement known as Wits appraisal (AOBO) was studied to determine its importance in diagnosis, treatment, and prediction of treatment success. The Wits appraisal is used primarily to identify unreliable ANB values (those that do not accurately reflect the degree of horizontal jaw discrepancy, ie, those that differ greatly from the AOBO value). Therefore, differences between AOBO and ANB also were evaluated. Because neither measurement alone can assess jaw discrepancies with total accuracy, they were combined, plotted on a scattergram, and divided into equal zones to create a new index of horizontal skeletal discrepancies and treatment predictability. Pretreatment values correspond to treatment difficulty, and posttreatment values correspond to the effectiveness of treatment. Treatment time for each zone also was evaluated. We were able to draw several conclusions from this study. First, combining AOBO and ANB values results in a more accurate measurement of treatment difficulty. These combined values also can be used to predict both treatment time and the success of treatment for horizontal discrepancies. Second, the AOBO value predicts variations in treatment time at each ANB value. Finally, adding ANB and AOBO values and then dividing the total yields zones that represent statistically significant differences in treatment times and percentages of success. The zones also correlate with the difference between AOBO and ANB measurements.  相似文献   
2.
3.
A crossover double-blind controlled trial was performed on 36 patients with rheumatoid arthritis to assess the necessity for serum salicylate monitoring in determining optimal dosage. There was no clinically or statistically significant increase in the clinical improvement of patients associated with serum monitoring but potentially toxic serum levels occurred without tinnitus when serum monitoring was not used.  相似文献   
4.
5.
Two sets of factors will ultimately influence the outcome of the burned upper extremity. The first set of factors is the depth and severity of the burn. The second set is the group of complications of the burn injury attributable to edema, inflammation, immobility, and malposition. An awareness of the potential pitfalls that follow burn injury has resulted in improved primary care and a lessening of deformity. Progressive acute care with topical chemotherapy, early motion, thoughtful splinting, and timely burn wound closure are essential to reduce the need for secondary operations. Reconstructive efforts should be tailored to the individual needs of the patient. These procedures should be carefully planned with a view toward balancing aesthetic and functional considerations and minimizing the time required for rehabilitation.  相似文献   
6.
An ECG and respiration-gated spin-labeling gradient-echo imaging technique is proposed for the quantitative and completely noninvasive measurement and mapping of myocardial perfusion in small animals in vivo. In contrast to snapshot FLASH imaging, the spatial resolution of the perfusion maps is not limited by the heart rate. A significant improvement in image quality is achieved by synchronizing the inversion pulse to the respiration movements of the animals, thereby allowing for spontaneous respiration. High-resolution myocardial perfusion maps (in-plane resolution=234 x 468 microm2) demonstrating the quality of the perfusion measurement were obtained at 4.7 T in a group of seven freely breathing Wistar-Kyoto rats under isoflurane anesthesia. The mean perfusion value (group average +/- SD) was 5.5 +/- 0.7 ml g(-1)min(-1). In four animals, myocardial perfusion was mapped and measured under cardiac dobutamine stress. Perfusion increased to 11.1 +/- 1.9 ml g(-1)min(-1). The proposed method is particularly useful for the study of small rodents at high fields.  相似文献   
7.
8.
Urogenital infections are established as hazards to male fertility. Various pathophysiological hypotheses have evolved from experimental and clinical studies, facilitating explanation of the effects of bacteria and immunological events on reproductive tissues. Numerous current studies have identified and evaluated infectious mediators accounting for specific molecular events in urogenital infections. Valuable studies can be expected to appear in the future due to improvements in diagnostic procedures and new classifications of urogenital infections.  相似文献   
9.
Defining the minimum clinically important difference or delta to be detected in a clinical trial depends on a number of factors including the research hypothesis, patient characteristics, the nature of the intervention and the trial design. In 2 previous studies, we have developed standardized procedures for conducting outcome measurement based on current Food and Drug Administration and European League Against Rheumatism guidelines for clinical trials in ankylosing spondylitis, and thereafter, determined the standard deviation for these outcome measures. In the final component of this series of studies, we have employed a Delphi technique to establish estimates for delta, and calculated the sample size requirements under 2 different conditions of Type I and Type II error probabilities.  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