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   2735篇
  免费   227篇
  国内免费   20篇
耳鼻咽喉   68篇
儿科学   96篇
妇产科学   51篇
基础医学   316篇
口腔科学   56篇
临床医学   436篇
内科学   463篇
皮肤病学   17篇
神经病学   188篇
特种医学   94篇
外科学   576篇
综合类   48篇
预防医学   177篇
眼科学   50篇
药学   194篇
中国医学   4篇
肿瘤学   148篇
  2022年   18篇
  2021年   32篇
  2020年   38篇
  2019年   37篇
  2018年   37篇
  2017年   45篇
  2016年   53篇
  2015年   52篇
  2014年   74篇
  2013年   102篇
  2012年   128篇
  2011年   139篇
  2010年   105篇
  2009年   106篇
  2008年   177篇
  2007年   173篇
  2006年   172篇
  2005年   160篇
  2004年   150篇
  2003年   144篇
  2002年   132篇
  2001年   49篇
  2000年   38篇
  1999年   43篇
  1998年   41篇
  1997年   39篇
  1996年   27篇
  1995年   26篇
  1994年   33篇
  1993年   28篇
  1992年   29篇
  1991年   25篇
  1990年   31篇
  1989年   28篇
  1988年   31篇
  1987年   35篇
  1986年   32篇
  1985年   30篇
  1984年   31篇
  1983年   19篇
  1982年   36篇
  1981年   21篇
  1980年   18篇
  1979年   17篇
  1978年   21篇
  1977年   20篇
  1976年   16篇
  1975年   15篇
  1974年   17篇
  1966年   13篇
排序方式: 共有2982条查询结果,搜索用时 11 毫秒
31.
32.
Periosteal Ewing sarcoma   总被引:3,自引:0,他引:3  
  相似文献   
33.
OBJECTIVES: To test the hypothesis that patients with non-small cell lung cancer and single-level N2 metastases constitute a favorable subgroup of patients with mediastinal metastases, we analyzed the results of the Eastern Cooperative Oncology Group 3590 (a randomized prospective trial of adjuvant therapy in patients with resected stages II and IIIa non-small cell lung cancer) by site of primary tumor and pattern of lymph node metastases. METHODS: Accurate staging was ensured by mandating either systematic sampling or complete dissection of the ipsilateral mediastinal lymph nodes. The overall survival of patients with left lung non-small cell lung cancer and metastases in only 1 of lymph node levels 5, 6, or 7 and right lung non-small cell lung cancer with metastases in only 1 of levels 4 or 7 was compared with that of patients with N1 disease originating in the same lobe. RESULTS: The median survival of the 172 patients with single-level N2 disease was 35 months (95% confidence interval: 27-40 months) versus 65 months (95% confidence interval: 45-84 months) for the 150 patients with N1 disease (median follow-up 84 months, P =.01). However, among patients with left upper lobe tumors, survival was not significantly different between patients with N1 disease and patients with single-level N2 disease (49 vs 51 months, P =.63). The median survival of the 71 patients with single-level N2 metastases without concomitant N1 disease (skip metastases) was 59 months (95% confidence interval: 36-107 months) versus 26 months (95% confidence interval: 16-36 months) for the 145 patients with both N1 and N2 metastases (P =.001). CONCLUSIONS: Survival of patients with left upper lobe non-small cell lung cancer and metastases to single-level N2 lymph nodes is not significantly different from that of patients with N1 disease. The presence of isolate N2 skip metastases is associated with improved survival when compared with patients with both N1 and N2 disease. Survival should be reported by the lobe of primary tumor and metastatic pattern to guide future clinical trial development, treatment strategies, and revisions of the TNM staging system.  相似文献   
34.
35.
The fear that patients with high-mathematical model for end stage liver disease (MELD) score may not be suitable candidates for segmental grafts because of their need for greater liver mass has continued to push the transplant community toward the use of whole LT (WLT) in preference to split LT (SLT). In order to define the outcome of segmental liver transplantation in a better manner in high-MELD patients (score ≥26), we queried the UNOS registry for graft and patient survival results according to MELD score in adult patients receiving WLT and SLT in the United States from the inception of MELD allocation (February 27, 2002) through March 9, 2007. A total of 316 adult patients received a SLT as compared with 20 778 WLTs. Patient and graft survival rates at 6 and 12 months were comparable for all MELD ranges, including the 'high-MELD' recipients (e.g. at MELD score 31–35, patients' and grafts' survival rates at 12 months was 87.5% in SLT group vs. 84.4% and 76.7% in WLT group respectively). The results even at higher MELD scores (i.e. >35) were more than acceptable. In conclusion, patient and graft survival rates for SLT in high-MELD adult patients are comparable to the same for WLT.  相似文献   
36.
Our earlier efforts to document the cortical connections of the ventral premotor cortex (PMv) revealed dense connections with a field rostral and lateral to PMv, an area we called the frontal rostral field (FR). Here, we present data collected in FR using electrophysiological and anatomical methods. Results show that FR contains an isolated motor representation of the forelimb that can be differentiated from PMv based on current thresholds and latencies to evoke electromyographic activity using intracortical microstimulation techniques. In addition, FR has a different pattern of cortical connections compared with PMv. Together, these data support that FR is an additional, previously undescribed motor-related area in squirrel monkeys.  相似文献   
37.
An incidental left adrenal mass was found in a patient during an evaluation for mediastinal widening. The patient had no symptoms attributable to adrenal excess. Preoperative biochemical screening was negative for a functioning medullary or cortical adrenal tumor. Surgical resection was successfully completed with the assistance of the da Vinci robotic system. Pathology demonstrated a rare adrenal oncocytoma.  相似文献   
38.
BACKGROUND: To study the mortality among morbidly obese patients qualifying for bariatric surgery. Mortality from bariatric surgery for morbid obesity has been widely reported; however, little is known about the mortality in morbidly obese patients who defer surgery. METHODS: Consecutive patients evaluated for bariatric surgery with an initial encounter between 1997 and 2004 were identified. The Social Security Death Index and office records were used to identify mortality through 2006. We conducted telephone interviews to determine whether the 305 patients who did not undergo bariatric surgery at our institution had undergone the surgery elsewhere. Using Cox proportional hazards models, we compared the mortality in patients undergoing surgery with that of those who did not. To evaluate bias resulting from missing data, we conducted analyses assuming that all patients with missing data had (1) undergone surgery and (2) not undergone surgery. RESULTS: A total of 908 patients underwent bariatric surgery (880 patients at our institution and 28 patients elsewhere). A total of 112 patients did not undergo surgery. Data regarding surgery on 165 patients could not be obtained. The mortality in those patients who did not undergo surgery was 14.3% compared with 2.9% for those who did undergo surgery. Adjusting for age, gender, and body mass index, patients who had undergone surgery had an 82% reduction in mortality (hazard ratio 0.18, 95% confidence interval 0.09-0.35, P <.0001). Sensitivity analysis, assuming that all patients with missing data received surgery resulted in an 85% mortality reduction (P <.001) and assuming that patients did not receive surgery resulted in a 50% mortality reduction (P = .04). CONCLUSIONS: Mortality among morbidly obese patients without surgery was 14.3% during the study period. Surgical intervention offered a 50%-85% mortality reduction benefit.  相似文献   
39.
BACKGROUND: Little is known about the level of knowledge and comfort with bariatric surgery among family practice physicians. METHODS: Surveys were sent to all family practitioners in Connecticut querying the practice type and knowledge of bariatric surgery. The results were analyzed for the prevalence of opinion. RESULTS: Of 620 surveys sent out, 129 (21%) were completed. Of the 129 respondents, 73% were men, aged 31-79 years, and 92% were board certified, with an average of 19 years' experience. The average body mass index of respondents was 26 kg/m2 (range 16-40). Only 4% of respondents had a body mass index >30 kg/m2. Physicians reported a patient obesity rate of 43%. Of the 129 respondents, 88% believed obesity was difficult to control with diet and exercise alone. Only 6% thought obesity was best controlled surgically. Also, 85% of respondents had referred a patient for gastric bypass, although only 57% were comfortable explaining the procedure. The most common reason for refusal to refer was fear of complications and death. Additionally, 55% correctly listed a body mass index of 40 kg/m2 as qualifying for bariatric surgery without comorbidities; 48% identified the mortality rate of surgery as <1%, with 4% of respondents reporting >10%; and 84% were familiar with gastric bypass, 66% with LapBand, 33% with vertical banded gastroplasty, and 5% with duodenal switch. The respondents believed that nausea was the most common side effect, followed by anemia and fatigue. Finally, 53% believed bowel obstruction was common. CONCLUSIONS: The results of our study have shown that misconceptions about bariatric surgery exist in the family practice community despite the increasing frequency of these procedures. Educational programs need to be designed to assist family practitioners in treating and referring obese patients.  相似文献   
40.
OBJECTIVE: This study was undertaken to further define the impact of intraoperative transesophageal echocardiography during surgery for congenital heart disease and to determine appropriate indications. METHODS: The impact of transesophageal echocardiography on patient care was assessed in 1002 patients who underwent this procedure during surgery for congenital heart defects. It had major impact when new information altered the planned procedure or led to a revision of the initial repair. The safety of intraoperative transesophageal echocardiography was evaluated by review of the prospective data sheets and the medical record. A simple relative cost analysis was also performed. RESULTS: Patient median age was 9.9 years (range 2 days to 85 years). Transesophageal echocardiography had prebypass or postbypass major impact in 13.8% of cases (n = 138/1002). Major impact was more frequent during reoperations (P <.03). Procedures that benefited most from the additional information were valve repairs (aortic or atrioventricular) and complex outflow tract reconstructions. Partial anomalous pulmonary venous connection, tricuspid valve repair (other than of Ebstein anomaly), simple atrioventricular discordance, aortic arch anomalies, and secundum atrial septal defects had major impact rates less than 5%. No major complications occurred. Minor complications occurred in 1% of patients and were most often observed in infants smaller than 4 kg. Routine use of transesophageal echocardiography for all patients with congenital heart defects proved cost-effective. CONCLUSIONS: On the combined basis of the observed rates of major impact, the minimal complications, and the relative cost advantage, we believe that routine use of transesophageal echocardiography during most intracardiac repairs of congenital heart defects is justified, particularly for patients undergoing repeat operations for congenital cardiac malformations.  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