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   1285篇
  免费   60篇
  国内免费   57篇
耳鼻咽喉   1篇
儿科学   116篇
妇产科学   13篇
基础医学   134篇
口腔科学   21篇
临床医学   144篇
内科学   286篇
皮肤病学   51篇
神经病学   34篇
特种医学   310篇
外科学   106篇
综合类   27篇
预防医学   39篇
眼科学   5篇
药学   54篇
中国医学   2篇
肿瘤学   59篇
  2023年   5篇
  2021年   7篇
  2020年   9篇
  2019年   8篇
  2018年   17篇
  2017年   3篇
  2016年   7篇
  2015年   14篇
  2014年   14篇
  2013年   42篇
  2012年   31篇
  2011年   27篇
  2010年   36篇
  2009年   56篇
  2008年   23篇
  2007年   64篇
  2006年   30篇
  2005年   30篇
  2004年   27篇
  2003年   37篇
  2002年   28篇
  2001年   14篇
  2000年   18篇
  1999年   21篇
  1998年   71篇
  1997年   79篇
  1996年   101篇
  1995年   61篇
  1994年   59篇
  1993年   52篇
  1992年   19篇
  1991年   15篇
  1990年   23篇
  1989年   39篇
  1988年   38篇
  1987年   35篇
  1986年   48篇
  1985年   44篇
  1984年   14篇
  1983年   17篇
  1982年   14篇
  1981年   13篇
  1980年   13篇
  1979年   11篇
  1978年   12篇
  1977年   11篇
  1976年   14篇
  1975年   15篇
  1974年   5篇
  1973年   6篇
排序方式: 共有1402条查询结果,搜索用时 15 毫秒
91.
Percutaneous nephrostolithotomy, which can require a double puncture, is presently the method of choice in our institution for the removal of renal stones. Patients that underwent this procedure were evaluated to identify the possible reasons for the double puncture. Of 200 patients evaluated, 14 needed a second tract. The three variables that determined whether a second puncture was needed, in order of importance, were number and size of the stones, with second tracts needed in patients with multiple stones and staghorn calculi; anatomical variations of the renal collecting system itself, with bifid systems the most significant anatomic variation; and the dexterity of the radiologist in performing the puncture and the ability of the urologist to extract the stone. Second tracts were needed more frequently in patients who presented with stones in both the lower and middle poles of the collecting systems.  相似文献   
92.
The preservation of red cell antigens at low ionic strength   总被引:1,自引:0,他引:1  
Low-ionic-strength saline (LISS) techniques permit a safe and substantial reduction in incubation time and have therefore become the method of choice for antibody detection and compatibility testing in many transfusion laboratories. Consequently, the supply of reagent red cells (RBCs) in a low-ionic-strength preservative solution would remove the daily need for laboratories to wash and resuspend cells in LISS before use. However, the storage of fresh RBCs at low ionic strength in the presence of aminoglycoside antibiotics can cause a rapid loss of certain antigens, possibly as a result of the release of proteolytic enzymes from contaminating white cells. This article describes a low-ionic-strength solution that achieves preservation of antigens on liquid nitrogen-frozen-thawed RBCs for 21 days' storage at 4 degrees C.  相似文献   
93.
Digital beam attenuator technique for compensated chest radiography   总被引:1,自引:0,他引:1  
The feasibility of producing patient-specific beam attenuators for chest radiography has been investigated using an anthropomorphic phantom and a human volunteer. A low-dose test exposure is digitized, processed, and used to print a small cerium filter, which is placed in the x-ray beam near the collimator. The final radiograph is recorded on film. The technique results in relatively uniform film exposure, so that structures in all regions of the chest are simultaneously displayed with optimal film contrast. The equalized exposure improves image quality in the normally underpenetrated regions and reduces the role of cross-scatter from the lungs. The image is analogous to optical or computer-processed unsharp masking techniques, but the processing is accomplished in the x-ray beam and results in an improved exposure distribution, giving advantages that cannot be achieved with image processing techniques alone.  相似文献   
94.
Medullary carcinoma of the breast: mammographic and US appearance   总被引:4,自引:0,他引:4  
  相似文献   
95.
直到最近为止,冠心病的内科治疗原则仍是降低心肌需氧量。由于粥样硬化病变一直认为是固定不变的狭窄,不可能增加冠脉血流量,因此认为用药物扩张冠状动脉是徒劳的。在近几年内这些概念有了基本转变。然而仅能引起远端心肌内小动脉扩张的药物却起着相反的作用。当心外膜冠状动脉有粥样硬化时,冠状小动脉扩张可加重血流分布异常,导致心肌缺血。冠状循环由近端大冠状动脉及其分枝小动脉组成的心肌内动脉网构成。近端大冠状  相似文献   
96.
The aim  of this study was to determine the frequency of body dysmorphic disorder (BDD) identified by Polish dermatologists and to evaluate the treatment modalities applied by them.
Methods  A specially designed questionnaire was distributed to 172 dermatologists. A total of 118 doctors responded (68.6%). The dermatologists were asked regarding demographic data, frequency of BDD in their everyday practice and methods of treatment they used in managing BDD patients.
Results  During the whole working period, over the half of dermatologists (64%) had observed at least one BDD patient in their practice. One fifth (20%) of the respondents observed 1 or 2 BDD cases during the past 5 years, 14% observed 3 to 5 such patients, 7% observed 5 to 10 BDD cases, and 5% of the doctors reported seeing more than 10 BDD patients within this period. Almost 18% of dermatologists were currently treating a BDD patient. Our data show that 40.7% of the respondents always ask and 28.8% often ask for a psychiatric opinion. More experienced dermatologists statistically more frequently ( P < 0.05) obtained a psychiatric opinion about their patients. Only a small group of dermatologists (15.3%) use their own pharmacological treatment. If they do so, they first use anxiety-relieving drugs and placebo.
Conclusion  BDD is a quite common disorder; however, not all dermatologists are sufficiently prepared to treat it. There is an urgent need for training of dermatologists on the effective approach to psychodermatoses.  相似文献   
97.
98.
99.
100.
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