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   11855篇
  免费   758篇
  国内免费   23篇
耳鼻咽喉   75篇
儿科学   417篇
妇产科学   232篇
基础医学   1382篇
口腔科学   156篇
临床医学   1296篇
内科学   1996篇
皮肤病学   148篇
神经病学   1546篇
特种医学   546篇
外科学   2009篇
综合类   122篇
一般理论   22篇
预防医学   1137篇
眼科学   108篇
药学   823篇
中国医学   24篇
肿瘤学   597篇
  2023年   62篇
  2022年   90篇
  2021年   245篇
  2020年   163篇
  2019年   271篇
  2018年   309篇
  2017年   209篇
  2016年   252篇
  2015年   240篇
  2014年   427篇
  2013年   586篇
  2012年   902篇
  2011年   952篇
  2010年   528篇
  2009年   484篇
  2008年   831篇
  2007年   797篇
  2006年   782篇
  2005年   825篇
  2004年   752篇
  2003年   716篇
  2002年   651篇
  2001年   99篇
  2000年   67篇
  1999年   89篇
  1998年   140篇
  1997年   102篇
  1996年   104篇
  1995年   90篇
  1994年   71篇
  1993年   54篇
  1992年   58篇
  1991年   45篇
  1990年   33篇
  1989年   39篇
  1988年   57篇
  1987年   40篇
  1986年   36篇
  1985年   29篇
  1984年   44篇
  1983年   45篇
  1982年   47篇
  1981年   33篇
  1980年   48篇
  1979年   26篇
  1978年   20篇
  1977年   19篇
  1976年   21篇
  1972年   14篇
  1971年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Cancer after Kidney Transplantation in the United States   总被引:7,自引:0,他引:7  
Previous reports of cancer after kidney transplantation have been limited by small numbers of patients in single-center studies and incomplete ascertainment of cases in large registries. We examined rates of malignancies among first-time recipients of deceased or living donor kidney transplantations in 1995-2001 (n = 35 765) using Medicare billing claims. For most common tumors, e.g. colon, lung, prostate, stomach, esophagus, pancreas, ovary and breast, cancer rates were roughly twofold higher after kidney transplantation compared with the general population. Melanoma, leukemia, hepatobiliary tumors, cervical and vulvovaginal tumors were each approximately fivefold more common. Testicular and bladder cancers were increased approximately threefold, while kidney cancer was approximately 15-fold more common. Kaposi's sarcoma, non-Hodgkin's lymphomas, and nonmelanoma skin cancers were more than 20-fold increased than in the general population. Compared with patients on the waiting list, several tumors were more common after transplantation (p < 0.01): nonmelanoma skin cancers (2.6-fold), melanoma (2.2-fold), Kaposi's sarcoma (9.0-fold), non-Hodgkin's lymphoma (3.3-fold), cancer of the mouth (2.2-fold), and cancer of the kidney (39% higher). The rates for most malignancies are higher after kidney transplantation compared with the general population. Cancer should continue to be a major focus of prevention in kidney transplantation.  相似文献   
102.
The shortage of cadaveric donors for simultaneous pancreas-kidney transplantation has prompted the use of cadaveric organs from pediatric donors. The long-term outcome and its impact on overall long-term survival are unknown. A total of 680 recipients receiving cadaver Simultaneous pancreas-kidney (SPK) transplantation from pediatric and adult donors between July 1986 and September 2001 were analyzed and compared. Ten-year kidney and pancreas graft survival for SPK transplantation from donors aged <18 years (n = 142) were 80% and 72%, respectively, compared to 61% pancreas and kidney graft survival from donors > or =18 years of age (n = 538; p = 0.03 and 0.05, respectively). Five years post-transplant, blood glucose, HbA1c and creatinine clearance were significantly better in recipients from pediatric donors (85.3 +/- 13 mg/dL, 5.5 +/- 3.5% and 65.6 +/- 16 mL/min, respectively), compared to recipients from adult donors (95.1 +/- 29 mg/dL, 5.9 +/- 3.5% and 58.3 +/- 17 mL/min; p = 0.001, 0.01 and 0.002, respectively). Causes of graft failure for kidney and pancreas transplants were similar between the two groups. No statistically significant difference was observed in patient survival between recipients from pediatric donors compared to adult donors (85% vs. 76%, p = 0.29). When recipients of SPK from pediatric donors were stratified according to age (3-11 years and 12-17 years) and compared, no difference in kidney or pancreas graft survival was observed (kidney 76.4% vs. 81.3%, p = 0.15; pancreas 75% vs. 76%, p = 0.10, respectively). Pediatric donors represent a valuable source of organs, providing excellent short- and long-term outcomes. Wide utilization of pediatric organs will substantially increase the donor pool.  相似文献   
103.
104.

Post–mortem computed tomography (PMCT) is a routine tool in many forensic pathology departments as it is fast and non-destructive and allows less gruesome visualization than photographs, and the images are indefinitely storable. Several studies investigated congruence between PMCT and autopsy for skull fracture but registered only the presence or absence of fracture systems. The objective of this study was to determine location-specific sensitivity and specificity of PMCT for individual fracture lines in blunt force head trauma. Accurate 3D models based on PMCT data with all fracture lines visible are important for future studies on fractures, applying finite element analysis (FEA). We retrospectively sampled adult cases from 2013 to 2019 with skull fracture mentioned in the autopsy report. PMCT was on a Siemens 64-slice scanner and autopsy according to international guidelines. The location and direction of all fracture lines at autopsy and at de novo interpretation of scans were registered and compared. Ninety-nine cases with 4809 individual findings were included. Age ranged from 18 to 100 years. The overall sensitivity was 0.58, and specificity was 0.91. For individual locations, sensitivity ranged from 0.24 to 0.85, and specificity ranged from 0.73 to 1.00. Intra-observer agreement was 0.74, and inter-observer agreement ranged from 0.43 to 0.58. In conclusion, PMCT is suited for detection of fracture systems, but not for detection of all individual fracture lines. Our results differed from the existing literature due to the methodological choices of registering individual fracture lines. Future studies utilising FEA must supplement PMCT with autopsy data.

  相似文献   
105.

Background  

Clinicians interested in assessment and outcome measurement of upper extremity (UE) function and performance in children with cerebral palsy (CP) must choose from a wide range of tools.  相似文献   
106.

Background  

Circumstances may arise during laparoscopic procedures in which alignment of the laparoscope and the instruments is off by 180°, creating a mirror image of the operative field. It has been shown that task performance is degraded under these reverse-alignment conditions, and that the magnitude of performance impairment is directly related to laparoscopic experience and skill. The aim of this study was to determine if reverse-alignment surgical skills could be developed through training.  相似文献   
107.
108.
BACKGROUND: Primary hyperoxaluria is a rare genetic disorder of glyoxylate metabolism that results in overproduction of oxalate. The disease is characterized by severe calcium oxalate nephrolithiasis and nephrocalcinosis, resulting in end-stage renal disease (ESRD) early in life. Most patients eventually require dialysis and kidney transplantation, usually in combination with the replacement of the liver. Reduction of urinary oxalate levels can efficiently decrease calcium oxalate depositions; yet, no treatment is available that targets oxalate biosynthesis. In previous in vitro studies, we demonstrated that pyridoxamine can trap reactive carbonyl compounds, including intermediates of oxalate biosynthesis. METHODS: The effect of PM on urinary oxalate excretion and kidney crystal formation was determined using the ethylene glycol rat model of hyperoxaluria. Animals were given 0.75% to 0.8% ethylene glycol in drinking water to establish and maintain hyperoxaluria. After 2 weeks, pyridoxamine treatment (180 mg/day/kg body weight) started and continued for an additional 2 weeks. Urinary creatinine, glycolate, oxalate, and calcium were measured along with the microscopic analysis of kidney tissues for the presence of calcium oxalate crystals. RESULTS: Pyridoxamine treatment resulted in significantly lower (by approximately 50%) levels of urinary glycolate and oxalate excretion compared to untreated hyperoxaluric animals. This was accompanied by a significant reduction in calcium oxalate crystal formation in papillary and medullary areas of the kidney. CONCLUSION: These results, coupled with favorable toxicity profiles of pyridoxamine in humans, show promise for therapeutic use of pyridoxamine in primary hyperoxaluria and other kidney stone diseases.  相似文献   
109.
Although HLA matching is beneficial in clinical transplantation, it is not feasible to select a completely HLA matched donor for every potential recipient because of the enormous polymorphism of the HLA system. As a consequence, the majority of the recipients will be transplanted with a mismatched donor organ or hematopoietic stem cell transplant. For this large group of patients it is important to take advantage of the differential immunogenicity of HLA mismatches and to select for them a donor with HLA mismatches of low immunogenicity, the so-called acceptable mismatches. The differential immunogenicity of HLA mismatches can be determined by either retrospective analysis of graft survival data or by in vitro assays measuring T-cell and B-cell alloreactivity. A recently developed computer algorithm (HLAMatchmaker) can be instrumental in selecting donors with HLA mismatches, which do not lead to alloantibody formation. The theoretical background and practical implications of this acceptable mismatch approach are discussed.  相似文献   
110.
BACKGROUND: Carotid stenting has been advocated in patients with grade III blunt carotid artery injuries (hereafter referred to as "blunt CAIs") because of the persistence of the pseudoaneurysm and concern for subsequent embolization or rupture. HYPOTHESIS: Carotid stenting is safe and effective for blunt CAIs. DESIGN: Analysis of a prospective database of all patients with blunt CAIs. SETTING: A state-designated, level I, urban trauma center.Patients and METHODS: In January 1, 1996, we initiated comprehensive screening for blunt CAIs with angiography based on injury patterns. Patients without contraindications receive anticoagulation therapy immediately for documented lesions. Patients with persistent pseudoaneurysms on a second angiography at 7 to 10 days after injury are candidates for stent placement. RESULTS: During the study period (January 1, 1996, to May 1, 2004), 46 patients sustained blunt carotid pseudoaneurysms; 23 (50%) underwent carotid stent placement. There were 4 complications in patients undergoing carotid stent placement: 3 strokes and 1 subclavian dissection. Follow-up angiography was performed in 38 patients (18 patients with stents who received antithrombotic agents, 20 patients who received antithrombotic agents alone); 8 patients had poststent carotid occlusion despite having received concurrent anticoagulation therapy. Carotid occlusion rates were significantly different (45% in patients with stents vs 5% in those who received antithrombotic agents alone). In the patients not undergoing stent placement, the only complication was a middle cerebral artery stroke in a patient not treated with antithrombotic therapy. CONCLUSIONS: Patients who have carotid stents placed for blunt carotid pseudoaneurysms have a 21% complication rate and a documented occlusion rate of 45%. In contrast, patients treated with antithrombotic agents alone had an occlusion rate of 5%; no asymptomatic patient treated with antithrombotic agents for their injury had a stroke. Antithrombotic therapy remains the recommended therapy for blunt CAIs, but the role of intraluminal stents remains to be defined.  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