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   36873篇
  免费   1904篇
  国内免费   1398篇
耳鼻咽喉   140篇
儿科学   187篇
妇产科学   65篇
基础医学   2281篇
口腔科学   566篇
临床医学   3008篇
内科学   4117篇
皮肤病学   47篇
神经病学   861篇
特种医学   2416篇
外国民族医学   1篇
外科学   14853篇
综合类   6444篇
预防医学   929篇
眼科学   378篇
药学   2063篇
  44篇
中国医学   1367篇
肿瘤学   408篇
  2024年   138篇
  2023年   564篇
  2022年   989篇
  2021年   1339篇
  2020年   1378篇
  2019年   994篇
  2018年   983篇
  2017年   1151篇
  2016年   1332篇
  2015年   1302篇
  2014年   2803篇
  2013年   2703篇
  2012年   2613篇
  2011年   2803篇
  2010年   2396篇
  2009年   2252篇
  2008年   1974篇
  2007年   2072篇
  2006年   1808篇
  2005年   1561篇
  2004年   1398篇
  2003年   1084篇
  2002年   843篇
  2001年   695篇
  2000年   483篇
  1999年   450篇
  1998年   333篇
  1997年   321篇
  1996年   246篇
  1995年   199篇
  1994年   149篇
  1993年   120篇
  1992年   97篇
  1991年   68篇
  1990年   45篇
  1989年   48篇
  1988年   47篇
  1987年   52篇
  1986年   47篇
  1985年   47篇
  1984年   29篇
  1983年   28篇
  1982年   44篇
  1981年   32篇
  1980年   20篇
  1979年   23篇
  1978年   12篇
  1977年   17篇
  1976年   9篇
  1975年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Central illustration: cumulative major adverse cardiac events (MACE) and bioresorbable vascular scaffold (BVS) thrombosis rates after 1, 2, 3, 4 and 5 years.
  相似文献   
2.
3.
PurposeTo retrospectively evaluate the safety and effectiveness of the Covera stent graft (SG) for the treatment of dysfunctional or thrombosed arteriovenous grafts (AVGs).Materials and MethodsWithin 29 months (February 2016–August 2018), 79 patients underwent Covera SG placement in the authors’ department for the treatment of dysfunctional AVGs. Data were available for 64 patients who underwent 64 procedures, using 64 devices. Minimum follow-up was 6 months, unless reintervention occurred. Mean follow-up was 277 days (6–923 days). Treatment characteristics were 51 cases with venous-graft anastomosis (VGA) stenosis (79.7%), 13 cases of puncture zone stenosis (20.3%), 14 cases of in SG stenosis (21.9%), 8 cases of pseudoaneurysm treatment (12.5%) (1 treatment area might have had more than 1 characteristic). Thirty-six patients presented with thrombosis (56.2%), and 31 of 64 case were de novo treatment areas (48.4%). Primary outcome measurements were technical success and post-intervention primary patency (PIPP) at 6 months, whereas secondary outcome measurements included factors influencing primary outcome.ResultsTechnical success was 100%. Median PIPP was 336 days, and 73.6% of treatment areas were patent at 6 months. There were no significant differences in terms of PIPP when de novo treatment areas were compared with restenotic areas (519 vs. 320 days, respectively; P = .1); patients who presented with versus those who presented without thrombosis (320 vs. 583 days, respectively; P = .07); puncture zone stenosis or elsewhere (329 vs. 686 days, respectively; P = .52); and VGA stenosis or elsewhere (336 vs. 335 days, respectively; P = .9).ConclusionsUse of the Covera SG for AVG treatment was safe and effective in every type of treatment area presented in this retrospective analysis.  相似文献   
4.
5.
6.
ObjectiveMultiple treatment options for acetabular fractures in geriatric patients exist. However, no large-scale studies have reported the outcomes of acute total hip arthroplasty (THA) in this patient population. We systematically evaluated all available evidence to characterize clinical outcomes, complications, and revisions of acute THA for acetabular fractures in geriatric patients.MethodsMeta-analysis of 21 studies of 430 acetabular fractures with mean follow-up of 44 months (range, 17−97 months). Two independent researchers searched and evaluated the databases of Ovid, Embase, and United States National Library of Medicine using a Boolean search string up to December 2019. Population demographics and complications, including presence of heterotopic ossification (HO), dislocation, infection, revision rate, neurological deficits, and venous thromboembolic event (VTE), were recorded and analyzed.ResultsWeighted mean Harris Hip Score was 83.3 points, and 20% of the patients had reported complications. The most common complication was HO, with a rate of 19.5%. Brooker grade III and IV HO rates were lower at 6.8%. Hip dislocation occurred at a rate of 6.1%, 4.1% of patients developed VTE, deep infection occurred in 3.8%, and neurological complications occurred in 1.9%. Although the revision rate was described in most studies, we were unable to perform a survival analysis because the time to each revision was described in only a few studies. The revision rate was 4.3%.ConclusionsAcute THA is a viable option for treatment of acetabular fracture and can result in acceptable clinical outcomes and survivorship rates in older patients but with an associated complication rate of approximately 20%. Considering the limited treatment options, THA might be a viable alternative for appropriately selected patients.  相似文献   
7.
目的 探讨复杂跟骨骨折治疗方法及AO钢板内固定价值.方法 应用AO钢板治疗累及距下关节的跟骨骨折24例,术中注意关节面复位和Bohler角的恢复.结果 24例病人经12~24个月随访,按照Fernandez评定标准:24例跟骨SandersⅡ-Ⅳ型骨折病人有18足评为优良.结论 距下关节面的复位和Bohler角的恢复,牢固的内固定和术后足够长时间的负重限制是成功的关键.  相似文献   
8.
关节镜辅助下钢板内固定治疗关节内跟骨骨折   总被引:3,自引:1,他引:2  
[目的]探讨分析关节镜辅助下钢板内固定治疗关节内跟骨骨折的方法和疗效;[方法]对78位患者,86例累及关节面的跟骨骨折在关节镜辅助下行切开复位钢板内固定术,术后平均随访18个月(12~30个月),通过比较术前术后X线片和踝足功能的AOFAS评分对治疗效果作分析评价.[结果]86例关节内跟骨骨折术后X线示复位满意.与术前存在显著性差异(P〈0.01),AOFAS评分优良率91.86%.[结论]对于关节内跟骨骨折,采用关节镜辅助钢板内固定更加接近解剖复位,足部功能恢复满意且并发症少  相似文献   
9.
Continual loading and articulation cycles undergone by metallic (e.g., titanium) alloy arthroplasty prostheses lead to liberation of a large number of metallic debris particulates, which have long been implicated as a primary cause of periprosthetic osteolysis and postarthroplasty aseptic implant loosening. Long-term stability of total joint replacement prostheses relies on proper integration between implant biomaterial and osseous tissue, and factors that interfere with this integration are likely to cause osteolysis. Because multipotent mesenchymal stem cells (MSCs) located adjacent to the implant have an osteoprogenitor function and are critical contributors to osseous tissue integrity, when their functions or activities are compromised, osteolysis will most likely occur. To date, it is not certain or sufficiently confirmed whether MSCs endocytose titanium particles, and if so, whether particulate endocytosis has any effect on cellular responses to wear debris. This study seeks to clarify the phenomenon of titanium endocytosis by human MSCs (hMSCs), and investigates the influence of endocytosis on their activities. hMSCs incubated with commercially pure titanium particles exhibited internalized particles, as observed by scanning electron microscopy and confocal laser scanning microscopy, with time-dependent reduction in the number of extracellular particles. Particulate endocytosis was associated with reduced rates of cellular proliferation and cell-substrate adhesion, suppressed osteogenic differentiation, and increased rate of apoptosis. These cellular effects of exposure to titanium particles were reduced when endocytosis was inhibited by treatment with cytochalasin D, and no significant effect was seen when hMSCs were treated only with conditioned medium obtained from particulate-treated cells. These findings strongly suggest that the biological responses of hMSCs to wear debris are triggered primarily by the direct endocytosis of titanium particulates, and not mediated by secreted soluble factors. In this manner, therapeutical approaches that suppress particle endocytosis could reduce the bioreactivity of hMSCs to particulates, and enhance long-term orthopedic implant prognosis by minimizing wear-debris periprosthethic osteolysis.  相似文献   
10.
The results of lumbar fusion in chronic low back pain (LBP) patients vary considerably, and there is a need for proper patient selection. Lumbosacral orthoses have been widely used to predict outcome, however, with little scientific support. The aim of the present study was to determine the value of a pantaloon cast test in selecting chronic LBP patients for lumbar fusion or conservative management. First, a systematic review of the literature was carried out in which two independent reviewers identified studies in Medline, Cochrane and Current Contents databases. Three papers met the selection criteria. In the only study with a control group, a significantly better outcome after fusion compared to conservative treatment was found in patients who reported significant pain relief while in a cast (i.e. a positive cast test). The results of lumbar fusion, however, were not significantly different for patients with a positive and those with a negative cast test. In addition to the review, a clinical cohort study of 257 LBP patients, who had been allocated to either lumbar fusion or conservative management by a temporary external transpedicular fixation trial, was performed. Prior to allocation, all had undergone a pantaloon cast test. Patients with no history of prior spine surgery and with a positive pantaloon cast test had a better outcome after lumbar fusion than those treated conservatively (P = 0.002, χ 2 test). In patients with previous spine operations the outcomes were poor and the test was of no value. From the literature and the present patient cohort, it was concluded that only in chronic LBP patients without prior spine surgery, a pantaloon cast test with substantial pain relief suggests a favorable outcome of lumbar fusion compared to conservative management. The test has no value in patients who have had previous spine surgery.  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