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   824篇
  免费   53篇
  国内免费   4篇
耳鼻咽喉   3篇
儿科学   45篇
妇产科学   5篇
基础医学   120篇
口腔科学   11篇
临床医学   54篇
内科学   131篇
皮肤病学   8篇
神经病学   26篇
特种医学   105篇
外科学   175篇
综合类   93篇
一般理论   1篇
预防医学   35篇
眼科学   12篇
药学   22篇
肿瘤学   35篇
  2022年   9篇
  2021年   8篇
  2020年   10篇
  2019年   5篇
  2018年   25篇
  2017年   15篇
  2016年   11篇
  2015年   23篇
  2014年   14篇
  2013年   21篇
  2012年   21篇
  2011年   33篇
  2010年   32篇
  2009年   35篇
  2008年   44篇
  2007年   47篇
  2006年   33篇
  2005年   39篇
  2004年   23篇
  2003年   16篇
  2002年   30篇
  2001年   25篇
  2000年   22篇
  1999年   20篇
  1998年   36篇
  1997年   27篇
  1996年   25篇
  1995年   27篇
  1994年   18篇
  1993年   14篇
  1992年   11篇
  1991年   6篇
  1990年   9篇
  1989年   17篇
  1988年   21篇
  1987年   22篇
  1986年   18篇
  1985年   7篇
  1984年   6篇
  1983年   7篇
  1982年   7篇
  1981年   5篇
  1980年   5篇
  1978年   2篇
  1977年   2篇
  1976年   4篇
  1975年   10篇
  1974年   2篇
  1973年   2篇
  1971年   2篇
排序方式: 共有881条查询结果,搜索用时 15 毫秒
1.
2.
The purpose of this study is to show the spectrum of adjacent organ invasion and to make a brief review of hepatic alveolar hydatid disease (AHD), using CT and MR imaging. We retrospectively reviewed CT and MR images of three patients with various adjacent organ invasions surgically and histologically proven to be AHD. Local invasion to right kidney and adrenal, right hemidiaphragm and lung were detected in one patient, right adrenal in another patient and gall bladder, duodenum, gastric wall and pancreas invasion in the other. AHD may rarely extend to the gall bladder, stomach, duodenum, pancreas, right adrenal and kidney, diaphragm, pleura and lung. The extension of the disease outside the liver is usually encountered in patients with large, peripherally located masses in the advanced stage of the disease.  相似文献   
3.
4.
Deprivation of form vision by the fitting of translucent occluders suppressed the diurnal cycling of enkephalinergic amacrine cells (the ENSLI amacrine cells), in the chicken. Daily periods of normal vision or enforcing temporal contrast using strobe lighting appeared to restore normal functioning of the ENSLI cells. These results suggest that the ENSLI cells are involved in retinal circuits that assess the quality of the visual image and control eye growth.  相似文献   
5.
Deep venous thrombosis: rate of spontaneous lysis and thrombus extension.   总被引:2,自引:0,他引:2  
AIM: Although recanalization occurs after an episode of venous thrombosis, the exact timing for this process, the rate of clearing at the different venous segments and the nature of the mechanisms involved and their progression are not well known. Recognition of these competing events is important in understanding the natural history and the mechanisms responsible for lysis of the thrombus and for the development of the post-thrombotic syndrome METHODS: During the course of 5 consecutive years, 110 patients (126 legs) with deep vein thrombosis (DVT) were prospectively followed using ultrasonic duplex. Follow-up studies were performed at intervals of 1 and 7 days, 1 month, every 3 months for the 1(st) year, and yearly thereafter. Mean duration of follow-up was 329 days. RESULTS: When only legs with initial complete occlusion are considered, the prevalence of occlusion progressively decreases to 33% after 6 months, 17% after the 1(st) year, and 0% after 3 years. Recanalization of individual segments occurred even more rapidly. After 3 months, recanalization of completely occluded segments was present in 93% of common femoral veins, 79% of superficial femoral veins (proximal segment), 84% of popliteal veins, and 72% of posterior tibial veins. The rate of recanalization was highest for multisegmental disease. Propagation of thrombi to adjacent venous segments occurred in 15% of the limbs. Propagation was usually limited to 1 or 2 adjacent segments. CONCLUSION: Lysis occurred early and was progressive. After 1 year most legs have recanalized. After 3 years recanalization occurred in all legs although residual thrombosis (partial obstruction) was still present in 50% of the limbs. Propagation of the thrombus was a limited process.  相似文献   
6.
7.
8.
Four noninvasive imaging modalities were used to quantitatively evaluate and compare tibial osteotomy healing in dogs. Quantitative computed tomography (QCT), magnetic resonance imaging (MRI), single-photon absorptiometry (SPA), and dual-energy x-ray absorptiometry (DEXA) were the four techniques examined. Bilateral tibial osteotomies were performed in 32 dogs divided into four groups. The osteotomies were stabilized with a 2-mm gap using unilateral external skeletal fixation. Dogs were anesthetized, imaged with the four noninvasive techniques, and killed at 2-12 weeks. Invasive techniques were used to determine: 1) the torsional properties of the bone; and 2) the local stiffness properties and calcium content within the bone. The techniques which had the strongest associations with the torsional properties of the osteotomies were QCT, SPA and DEXA. Generally, QCT and SPA had marginally stronger correlations than DEXA; but, overall, there were no differences between the techniques. MRI had the poorest associations with the torsional properties of the osteotomies. Generally, QCT had the strongest correlations with local material properties, such as indentation stiffness and calcium content. SPA had the second strongest correlations with calcium content and had the third strongest correlations with indentation stiffness behind DEXA. DEXA had the third strongest correlations for calcium content. With the exception of some of the correlations with indentation stiffness, MRI had the poorest associations with the local parameters studied.  相似文献   
9.
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