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   2534篇
  免费   97篇
  国内免费   8篇
耳鼻咽喉   10篇
儿科学   42篇
妇产科学   16篇
基础医学   321篇
口腔科学   58篇
临床医学   168篇
内科学   683篇
皮肤病学   37篇
神经病学   214篇
特种医学   115篇
外科学   378篇
综合类   5篇
预防医学   79篇
眼科学   49篇
药学   216篇
中国医学   10篇
肿瘤学   238篇
  2023年   8篇
  2022年   17篇
  2021年   39篇
  2020年   22篇
  2019年   32篇
  2018年   29篇
  2017年   23篇
  2016年   40篇
  2015年   41篇
  2014年   64篇
  2013年   86篇
  2012年   127篇
  2011年   143篇
  2010年   79篇
  2009年   74篇
  2008年   120篇
  2007年   150篇
  2006年   154篇
  2005年   182篇
  2004年   174篇
  2003年   184篇
  2002年   168篇
  2001年   58篇
  2000年   39篇
  1999年   52篇
  1998年   52篇
  1997年   41篇
  1996年   37篇
  1995年   37篇
  1994年   35篇
  1993年   29篇
  1992年   46篇
  1991年   32篇
  1990年   26篇
  1989年   34篇
  1988年   28篇
  1987年   27篇
  1986年   22篇
  1985年   17篇
  1984年   12篇
  1983年   10篇
  1982年   13篇
  1981年   4篇
  1980年   3篇
  1979年   7篇
  1977年   2篇
  1976年   4篇
  1975年   2篇
  1974年   3篇
  1964年   2篇
排序方式: 共有2639条查询结果,搜索用时 671 毫秒
1.
2.
3.
4.
OBJECTIVE: The baseball-diamond principle is generally used for trocar placement during video-assisted thoracic surgery; however, we are unable to treat all peripheral lung lesions using this principle. Therefore, we have developed another method for determining trocar placement based on a modification of the conventional principle. We have termed this method the triangle target principle. This report describes the instrument positioning that we now use for many video-assisted thoracic surgical procedures. METHODS: We position 3 trocars in an equilateral triangle, with the target lesion at the apex. One vertex of the base becomes the site of the first trocar placement for introduction of the thoracoscopic camera. Another vertex of the base becomes the site for the second trocar for forceps or the endoscopic stapler. The third trocar is for forceps and is inserted to create the vicinity of target lesion. Four types of the triangle target principle were developed according to sites of the target lesion. RESULTS: Between January 2000 and December 2002, we used this principle for 161 patients who underwent video-assisted thoracic surgery and all intrathoracic lesions were accessible except in 3 patients requiring intraoperative modifications. CONCLUSIONS: We conclude that video-assisted thoracic surgery by this principle is more effective and easier than the conventional principle to treat intrathoracic disease.  相似文献   
5.
A 64-year-old man, who had an aneurysm of aortic arch associated with the aberrant right subclavian artery, was treated successfully. He was pointed out to have an aneurysm of aortic arch three years ago. Three years later angiograms and computed tomography revealed that it became larger compared with the initial finding. He underwent a replacement of the aortic arch using a woven Dacron graft under open distal method. Aberrant subclavian artery was not involved in the aneurysm. But because the left subclavian artery was involved in it, a woven Dacron graft was interposed between the ascending aorta and left subclavian artery. Postoperative course was uneventful and there were no complications.  相似文献   
6.
The reductive retention of62Cu-PTSM was comparatively studied in the brain and Ehrlich ascites tumor cells by electron spin resonance spectrometry and nonradioactive Cu-PTSM. In the brain, only the mitochondrial fraction showed the ability to reduce Cu-PTSM, and the other subcellular fractions did not. In contrast, the cytosolic fraction of Ehrlich ascites tumor cells was the specific site of Cu-PTSM reduction. It was therefore considered that the retention of Cu-PTSM in the brain is closely related to mitochondrial reduction, most probably involving the mitochondrial electron transport system.  相似文献   
7.
We studied choline acetyltransferase (CAT) activity in a rat model of brachial plexus injury. In experiment 1, we found that the CAT activity was remarkably high in the anterior roots and low in the posterior roots. In experiment 2, nerve root segments were extracted and examined for CAT activity in the root avulsion group (group A) and the plexus severance group (group B). CAT activity decreased day by day in group A, reaching about 1/20 of the normal 5 days postoperatively. By contrast, in group B activity decreased only slightly, and even at 90 days postoperatively was about 6,000 cpm (one-half normal level). As a result, CAT activity enabled us to distinghish postganglionic from preganglionic injury of the cervical roots. Furthermore, it was a useful adjunct for minimizing nerve loss in intercostal nerve transfer, distinguishing motor and sensory branches of the intercostal nerve, and evaluating the motor nerve activity. © 1995 Wiley-Liss, Inc.  相似文献   
8.
Because gastric cancers located in the upper third of the stomach are difficult to detect at an early stage, the surgical results remain poor. We performed R4 gastrectomy as a radical procedure for 25 patients, involving complete resection of the latero-aortic and interaorticovenous lymph modes above and below the left renal vein, in combination with the ordinary R2 or R3 gastrectomy (the R4 group). These patients were compared with 156 others who underwent R2 gastrectomy alone (the R2 group). There were no significant differences in operation time, blood loss, or the incidence of complications between the two groups; however, when the survival rates of the patients with tumors invading beyond the subserosa were compared, the 5-year survival rate was found to be significantly higher in the R4 group than in the R2 group. Furthermore, in patients with para-aortic nodal involvement, a significant survival advantage was observed in the R4 group, as compared with the R2 group. These results suggest that the R4 gastrectomy is a rational approach for patients with advanced gastric cancer located in the upper third of the stomach.  相似文献   
9.
Between January in 1988 and September in 1990, 65 patients underwent reoperation for acquired heart disease. Previous operations were closed mitral commissurotomy in 19, open mitral commissurotomy in 19, mitral valve replacement in 22, aortic valve replacement in one, and mitral repair in 4. After median sternotomy performed by hand-operated chisel and hammer, minimized dissection of the adhesive lesion was achieved. During the sternotomy, two patients required additional right thoracotomy because of marked median sternal adhesion and major cardiovascular injury occurred in three patients. Cardioplegic solution was introduced in normograde fashion except in two patients. In two patients with previous MVR by porcine prosthesis severe calcification was found in the left atrial wall and the prosthesis was not removed in one. Postoperative complications were low cardiac output syndrome requiring intra-aortic balloon pumping in two, re-thoracotomy due to hemorrhage in one, and mild air embolism without neurological damage in two. There was one early death (1.5%) but no late death. Although perioperative complication seemed to increase in reoperation, post-reoperative results was as good as those in the primary cardiac operation and reoperation on cardiac surgery should be performed before losing the indication for operation.  相似文献   
10.
A 46-year-old man was referred to our hospital because of prosthetic valve regurgitation. Eight years previously he had undergone aortic valve replacement because of aortic regurgitation due to infective endocarditis. At reoperation, we found prosthetic valve endocarditis and discrete subaortic stenosis. The obstructing fibrous tissue was resected and the aortic valve was replaced. Because discrete subaortic stenosis is usually located just below the aortic valve, the aortic valve cusps are liable to become thickened by the jet through the discrete stenosis and thus are vulnerable to infective endocarditis. It is pointed out that care must be taken not to overlook discrete subaortic stenosis in the presence of other associated cardiac disorders.  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