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   1038篇
  免费   91篇
  国内免费   13篇
耳鼻咽喉   10篇
儿科学   33篇
妇产科学   32篇
基础医学   133篇
口腔科学   36篇
临床医学   117篇
内科学   236篇
皮肤病学   28篇
神经病学   61篇
特种医学   144篇
外科学   96篇
综合类   11篇
预防医学   51篇
眼科学   17篇
药学   41篇
中国医学   8篇
肿瘤学   88篇
  2023年   7篇
  2022年   6篇
  2021年   28篇
  2020年   10篇
  2019年   24篇
  2018年   31篇
  2017年   17篇
  2016年   22篇
  2015年   22篇
  2014年   34篇
  2013年   53篇
  2012年   34篇
  2011年   45篇
  2010年   41篇
  2009年   54篇
  2008年   46篇
  2007年   62篇
  2006年   54篇
  2005年   41篇
  2004年   35篇
  2003年   24篇
  2002年   29篇
  2001年   17篇
  2000年   15篇
  1999年   15篇
  1998年   53篇
  1997年   48篇
  1996年   23篇
  1995年   27篇
  1994年   15篇
  1993年   14篇
  1992年   4篇
  1991年   10篇
  1990年   13篇
  1989年   14篇
  1988年   18篇
  1987年   15篇
  1986年   22篇
  1985年   16篇
  1984年   10篇
  1983年   12篇
  1982年   6篇
  1981年   10篇
  1980年   11篇
  1979年   7篇
  1977年   3篇
  1976年   5篇
  1975年   6篇
  1973年   2篇
  1972年   2篇
排序方式: 共有1142条查询结果,搜索用时 187 毫秒
1.
BACKGROUND: There are obvious advantages to increasing donor retention. However, for reasons of blood safety, certain donors may, in fact, be more desirable to retain than others. “Safe” donors are defined as those who provided a blood donation that was negative on all laboratory screening tests and who subsequently reported no behavioral risks in response to an anonymous survey. This study identifies the most important factors affecting the intention of “safe” donors to provide another donation. STUDY DESIGN AND METHODS: An anonymous survey asking about donation history, sexual history, injecting drug use, and recent donation experience was mailed to 50,162 randomly selected allogeneic donors (including directed donors) who gave blood from April through July or from October through December 1993 at one of the five United States blood centers participating in the Retrovirus Epidemiology Donor Study. Before mailing, questionnaires were coded to designate donors with nonreactive laboratory screening tests at their most recent donation. RESULTS: A total of 34,726 donors (69%) responded, with substantially higher response among repeat donors. According to reported intentions only, the vast majority of “safe” donors indicated a high likelihood of donating again within the next 12 months. Only 3.4 percent reported a low likelihood of donating again. A comparison of those likely to return and those unlikely to return reveals significant differences in demographics and in ratings of the donation experience. A higher proportion of those unlikely to return were first-time donors, minority-group donors, and donors with less education. The highest projected loss among “safe” donors was seen for those who gave a fair to poor assessment of their treatment by blood center staff or of their physical well-being during or after donating. CONCLUSION: These data suggest that efforts to improve donors' perceptions of their donation experience, as well as attention to the physical effects of blood donation, may aid in the retention of both repeat and first-time donors.  相似文献   
2.
PURPOSE: A prospective radiographic study analyzed condylar position in patients who had undergone orthodontic treatment and isolated maxillary advancement after Le Fort I osteotomy. PATIENTS AND METHODS: Eleven patients were selected and radiographic images were taken in the immediate preoperative, immediate postoperative (1-2 weeks), and late postoperative periods (minimum of 6 months). Tracings were done on acetate paper for the submento-vertex radiograph, to measure the axial angulation of the condyles, and for the tomographic images of both sides, in the maximal intercuspation, rest position, and maximal opening, for the 3 periods. Linear measurements were taken for the tomograms over the posterior, superior, and anterior articular spaces. These images with the tracings were digitized and measured by means of computer software (UTHSCSA Image Tool 3.0; University of Texas Health Science Center at San Antonio, San Antonio, TX), after it had been adequately calibrated. RESULTS: The analysis of variance (ANOVA; 5% of significance) demonstrated 1) that there was no statistically significant difference for the linear measurements of the articular spaces in any of the periods, and 2) also not for the angular measure of the condyles (P > .05). In the maximal opening, there was a significant difference for the immediate postoperative period for both sides (P = .003). CONCLUSION: Le Fort I osteotomy for maxillary advancement did not cause any significant changes in this specific group of patients evaluated.  相似文献   
3.
Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.  相似文献   
4.
Intestinal schistosomiasis japonica: CT-pathologic correlation   总被引:1,自引:0,他引:1  
  相似文献   
5.
Vascular complications of pancreatic transplantation: MR evaluation   总被引:8,自引:0,他引:8  
Krebs  TL; Daly  B; Wong  JJ; Chow  CC; Bartlett  ST 《Radiology》1995,196(3):793
  相似文献   
6.
7.
8.
Lafora disease (LD) is a fatal and the most common form of adolescent-onset progressive epilepsy. Fulminant endoplasmic reticulum (ER)-associated depositions of starch-like long-stranded, poorly branched glycogen molecules [known as polyglucosans, which accumulate to form Lafora bodies (LBs)] are seen in neuronal perikarya and dendrites, liver, skeletal muscle and heart. The disease is caused by loss of function of the laforin dual-specificity phosphatase or the malin E3 ubiquitin ligase. Towards understanding the pathogenesis of polyglucosans in LD, we generated a transgenic mouse overexpressing inactivated laforin to trap normal laforin's unknown substrate. The trap was successful and LBs formed in liver, muscle, neuronal perikarya and dendrites. Using immunogold electron microscopy, we show that laforin is found in close proximity to the ER surrounding the polyglucosan accumulations. In neurons, it compartmentalizes to perikaryon and dendrites and not to axons. Importantly, it binds polyglucosans, establishing for the first time a direct association between the disease-defining storage product and disease protein. It preferentially binds polyglucosans over glycogen in vivo and starch over glycogen in vitro, suggesting that laforin's role begins after the appearance of polyglucosans and that the laforin pathway is involved in monitoring for and then preventing the formation of polyglucosans. In addition, we show that the laforin interacting protein, EPM2AIP1, also localizes on the polyglucosan masses, and we confirm laforin's intense binding to LBs in human LD biopsy material.  相似文献   
9.
10.
The presence of a damaged tube has been suggested in recent studies to have a negative effect on in-vitro fertilization (IVF) outcome. Performing bilateral salpingectomy prior to IVF to maximize pregnancy rates may also result in unnecessary surgery. This case is also an example of the occurrence of interstitial pregnancy after salpingectomy. This unusual type of ectopic pregnancy must be kept in mind when evaluating a patient suspected of a possible early abnormal gestation after assisted reproductive technolologies.   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