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   5107篇
  免费   362篇
  国内免费   22篇
耳鼻咽喉   84篇
儿科学   156篇
妇产科学   90篇
基础医学   717篇
口腔科学   260篇
临床医学   542篇
内科学   876篇
皮肤病学   82篇
神经病学   471篇
特种医学   205篇
外科学   977篇
综合类   18篇
一般理论   3篇
预防医学   248篇
眼科学   110篇
药学   318篇
中国医学   2篇
肿瘤学   332篇
  2023年   26篇
  2022年   38篇
  2021年   83篇
  2020年   54篇
  2019年   68篇
  2018年   107篇
  2017年   74篇
  2016年   109篇
  2015年   127篇
  2014年   169篇
  2013年   224篇
  2012年   303篇
  2011年   345篇
  2010年   213篇
  2009年   216篇
  2008年   299篇
  2007年   292篇
  2006年   312篇
  2005年   291篇
  2004年   252篇
  2003年   259篇
  2002年   222篇
  2001年   85篇
  2000年   119篇
  1999年   112篇
  1998年   67篇
  1997年   40篇
  1996年   48篇
  1995年   38篇
  1994年   35篇
  1993年   35篇
  1992年   56篇
  1991年   58篇
  1990年   51篇
  1989年   37篇
  1988年   63篇
  1987年   43篇
  1986年   45篇
  1985年   33篇
  1984年   33篇
  1983年   20篇
  1982年   27篇
  1980年   23篇
  1979年   22篇
  1978年   22篇
  1974年   21篇
  1973年   25篇
  1972年   19篇
  1968年   18篇
  1967年   18篇
排序方式: 共有5491条查询结果,搜索用时 15 毫秒
1.
2.
Altern heute     
Reflecting on the attitude to one's own aging process and a deeper wrestling with one's own purpose, as well as contemplating the life situation of aging seniors forms an essential access to the understanding of their experience. The structure of the aging process has changed and we need new visions with an emphasis on realizing a new, conscious, independent phase of life. While exploring the past offers an important resource in navigating through the aging process, persons with no vision of the future or who continue to define themselves by no longer viable roles and functions are at risk for developing psychological damage and disorders. Therefore, it is a central tenant in psychotherapy with seniors to combine work on the past with actual challenges in the present such as reduction in physical and mental capacities, the possibility of going into a retirement or nursing home, redefining one's identity after retirement and dealing with one's mortality.  相似文献   
3.
4.
The vascular endothelium plays an important and complex role in vascular allograft rejection. Antigens expressed by the endothelium can act to promote and be the target of rejection reactions, which often lead to thrombosis and ischemic necrosis of the allograft. In this study, segments of femoral artery and femoral vein with or without endothelium were grafted between allogenic or autologous control rats. Immunocompetent Lewis (RT1(1] recipient rats were randomly selected for groups (N = 14 for each) receiving the following: ACI- (RT1a) allografts with intact endothelium, allografts with endothelium removed before operation, autografts with endothelium, and autografts with endothelium removed. Rejection was assessed by graft patency as well as morphologic and ultrastructural changes. At 5 days, the allografts with intact endothelium were totally occluded, whereas allografts without endothelium remained patent, as did autologous control grafts with or without endothelium. Two additional groups (N = 14 each) receiving the de-endothelialized allografts or autografts were examined at 120 days after operation, revealing that grafts in both groups were still patent and had been re-endothelialized. These findings indicate that physical removal of vascular endothelium may depress vessel allograft rejection without immunosuppressive therapy.  相似文献   
5.
OBJECTIVES: Prompt diagnosis of subsequent dilatation of the dissected aorta is crucial to reduce late mortality in these patients. This study focuses on risk factors for dilatation of the aorta after type A aortic dissection (AADA) affecting a normal-sized or slightly dilated aorta. METHODS: Overall 531 CT scans were analysed. Patients were included in the study if at least 3 CT scans were available after operative repair. 64 patients (59.8%) out of 107 patients full-field the inclusion criteria. Volumetric analyses of the aorta were performed. Patients were divided in 3 groups: group A included 26 patients (40.6%) without progression of the aortic diameter, group 2, 27 patients (42.2%) with slight progression and group 3, 11 patients (17.2%) with important progression, requiring surgery in 9 patients (81.8%). Risk-factors for progression of the aortic size were analysed and compared between the groups. RESULTS: Patients from group 3 were younger 57.7+/-13.4 vs. 61.9+/-11.6 in group 1 (P<0.05) and were more frequent female (45.4 vs. 23.1%; P<0.05). Dissection of the supraaortic branches (100 vs. 80.8%; P<0.05), the presence of preoperative cerebral, visceral or peripheral malperfusion (54.6 vs. 26.9%; P<0.05) and contrast enhancement in the false lumen during the follow-up (72.7 vs. 57.7%; P=0.07) were additional risk factors for late aortic dilatation in these patients. CONCLUSIONS: Acute type A aortic dissection in younger patients, involving the supraaortic branches and/or combined with malperfusion syndrome favour secondary dilatation. A close follow-up is mandatory to prevent acute complications of the diseased downstream aorta following repair of a AADA.  相似文献   
6.
The kinetics of the association of polymorphonuclear leukocytes (PMNs) with arterial balloon catheter-induced injury have been examined. An average of 6 X 10(7) PMNs were isolated from 20 ml of blood and labelled with 111In-oxine for reinfusion into the donor rabbit. The cells remained viable as demonstrated by both in vitro and in vivo tests of cell function. The abdominal aorta of rabbits was denuded of endothelium and immediately, 24 h, or 5 weeks later, exposed to autologous radiolabelled PMNs for 1 h. The presence of PMNs at sites of denudation was demonstrated by detection of the radioactive label and was confirmed by light and electron microscopy after 24 h, but not at 5 weeks. Immediately following denudation radioactivity was 2.44 +/- 0.33 times control (P = 0.006); 2.52 +/- 0.18 at 24 h (P = 0.005); and 1.88 +/- 0.32 times control at 5 weeks (P = 0.045). The presence of PMNs, or their products, 5 weeks after denudation suggests a more complex role of PMNs and possibly a direct involvement in the long term changes resulting from arterial balloon catheter injury.  相似文献   
7.
Dysphagia was studied in 29 patients after implantation of an Angelchik prosthesis for persistent reflux oesophagitis. The incidence of postoperative dysphagia occurred after three months (61%), six months (45%), and one year or more (41%). Severe dysphagia necessitated removal of the prosthesis in five patients (17%). The reoperative findings with regard to a possible explanation of dysphagia are discussed, and comparison is made with reports in literature. Implantation of the Angelchik prosthesis seems only indicated for the treatment of intractable reflux oesophagitis in patients where other operative modalities failed and who are at high risk for operation. The Nissen fundoplication remains the operation of choice.  相似文献   
8.
The synthesis of the title compounds starting from 2-Chlormethylbenzdioxan and Tetrahydroisochinolines is presented. Their actions on the platelet aggregation and the inhibition of alpha-adrenoceptors at the isolated rabbit aorta and the vas deferens of the guinea pig were investigated.  相似文献   
9.
10.
Abstract: In order to evaluate the level of evidence of factors influencing the survival of reconstructions, systematic reviews of the relevant literature were prepared by a group of rapporteurs. The review papers were circulated to the members of the group before the conference and formed the basis for group and panel discussions. Subsequently, modifications were added to the review papers, and suggestions for consensus statements concerning the following topics were prepared and again critically reviewed in the group and in the plenum: Impact of (i) periodontal disease on the survival of tooth-supported reconstructions, (ii) post-surgical factors as supportive therapy on the survival of implant supported reconstructions, (iii) technical and/or biological complications on the survival of different types of reconstructions, (iiii) material choice for reconstructions on the survival of single crowns and fixed dental prostheses.  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