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   3397篇
  免费   245篇
  国内免费   24篇
耳鼻咽喉   78篇
儿科学   89篇
妇产科学   81篇
基础医学   465篇
口腔科学   55篇
临床医学   378篇
内科学   647篇
皮肤病学   61篇
神经病学   288篇
特种医学   169篇
外科学   629篇
综合类   21篇
预防医学   185篇
眼科学   71篇
药学   200篇
中国医学   1篇
肿瘤学   248篇
  2022年   33篇
  2021年   60篇
  2020年   34篇
  2019年   45篇
  2018年   77篇
  2017年   44篇
  2016年   69篇
  2015年   94篇
  2014年   109篇
  2013年   139篇
  2012年   179篇
  2011年   208篇
  2010年   145篇
  2009年   140篇
  2008年   149篇
  2007年   149篇
  2006年   180篇
  2005年   151篇
  2004年   121篇
  2003年   130篇
  2002年   106篇
  2001年   71篇
  2000年   109篇
  1999年   95篇
  1998年   72篇
  1997年   43篇
  1996年   47篇
  1995年   29篇
  1994年   35篇
  1993年   28篇
  1992年   49篇
  1991年   48篇
  1990年   48篇
  1989年   34篇
  1988年   60篇
  1987年   40篇
  1986年   47篇
  1985年   33篇
  1984年   28篇
  1983年   19篇
  1982年   32篇
  1980年   20篇
  1979年   18篇
  1978年   18篇
  1977年   19篇
  1975年   18篇
  1973年   22篇
  1972年   16篇
  1970年   16篇
  1968年   18篇
排序方式: 共有3666条查询结果,搜索用时 15 毫秒
1.
2.
BACKGROUND: On December 26, 2004, the biggest earthquake for 40 years, measuring 9.0 on the Richter scale, triggered a tsunami that pounded the coastal areas of South Asia and East Africa. The effects of the tsunami on skin conditions have not been evaluated. OBJECTIVE: To determine the influence of the tsunami on skin conditions by evaluating the skin problems of patients presenting at hospitals after the tsunami. METHODS: Between 5 and 25 January 2005, two dermatologists evaluated patients who complained of skin problems at an outpatient clinic and emergency room of a general hospital in Banda Aceh, Aceh Province, Indonesia. RESULTS: The total number of patients that presented during the study period was 235 (131 males and 104 females), and they had a total of 265 skin problems. In terms of age distribution, most subjects were in their fourth decade (23.0%), followed by the third (22.6%) and fifth decade (16.6%). The most prevalent skin problems were infections-infestations (32.5%), followed by eczemas (29.8%) and traumatic skin disorders (29.4%). In males, traumatic skin disorders were most common. The great majority of infection-infestation cases involved superficial fungal infections. Contact dermatitis accounted for three-quarters of eczema cases, and mainly involved the arms (40.0%) and legs (27.1%). The majority of traumatic skin disorders were lacerations, punctures and penetrations, and the feet (44.7%) and hands (18.8%) were most frequently affected. CONCLUSIONS: Unhygienic conditions, exposure to a hazardous environment and contact with various objects during and after the tsunami probably increased the prevalence of infections-infestations, traumatic skin disorders and contact dermatitis. To prevent these problems and associated secondary bacterial infections, health-related education and early medical management are required.  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.
9.
10.
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   
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