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   36678篇
  免费   2872篇
  国内免费   429篇
耳鼻咽喉   391篇
儿科学   1032篇
妇产科学   963篇
基础医学   4675篇
口腔科学   605篇
临床医学   3919篇
内科学   7864篇
皮肤病学   861篇
神经病学   2429篇
特种医学   1464篇
外科学   4919篇
综合类   1194篇
一般理论   32篇
预防医学   1966篇
眼科学   1589篇
药学   2771篇
中国医学   307篇
肿瘤学   2998篇
  2023年   241篇
  2022年   421篇
  2021年   964篇
  2020年   614篇
  2019年   792篇
  2018年   1004篇
  2017年   771篇
  2016年   877篇
  2015年   1061篇
  2014年   1384篇
  2013年   1662篇
  2012年   2352篇
  2011年   2468篇
  2010年   1449篇
  2009年   1278篇
  2008年   1930篇
  2007年   2046篇
  2006年   2009篇
  2005年   1950篇
  2004年   1709篇
  2003年   1594篇
  2002年   1431篇
  2001年   1135篇
  2000年   1070篇
  1999年   928篇
  1998年   448篇
  1997年   350篇
  1996年   350篇
  1995年   278篇
  1994年   274篇
  1993年   261篇
  1992年   473篇
  1991年   469篇
  1990年   446篇
  1989年   426篇
  1988年   382篇
  1987年   393篇
  1986年   354篇
  1985年   304篇
  1984年   216篇
  1983年   167篇
  1982年   114篇
  1981年   106篇
  1980年   106篇
  1979年   142篇
  1978年   98篇
  1977年   86篇
  1976年   89篇
  1975年   84篇
  1972年   69篇
排序方式: 共有10000条查询结果,搜索用时 796 毫秒
71.
Conventional work-up (CWU) with chest radiography, abdominal ultrasonography, and skeletal scintigraphy has limited value in M staging of nonkeratinizing nasopharyngeal carcinoma (NPC). Our aim was to evaluate whether (18)F-FDG PET could replace CWU by comparing their diagnostic efficacies. METHODS: Patients with histologically proven nonkeratinizing NPC and no prior treatment were prospectively enrolled. All study participants underwent CWU and (18)F-FDG PET for primary M staging. Distant metastasis was considered to be present if there was any reliable evidence identified within 1 y after diagnosis. The comparative diagnostic efficacies of (18)F-FDG PET, CWU, and the combination of (18)F-FDG PET and CWU (PET+CWU) were evaluated using the areas under the receiver-operating-characteristic (ROC) curves. RESULTS: Sixty-one (20.3%) of 300 eligible patients were found to have distant metastases. On a patient-based analysis, (18)F-FDG PET was found to be more effective than CWU (P < 0.001), whereas it was equally effective with PET+CWU (P = 0.130). On region-based analyses, (18)F-FDG PET was more effective than skeletal scintigraphy and chest radiography for detecting bone metastases (P < 0.001) and chest metastases (P < 0.001), respectively. (18)F-FDG PET and abdominal ultrasound were equally effective for detecting hepatic metastases (P = 0.127). On region-based analyses, the combination of (18)F-FDG PET and CWU did not yield any noticeable increase in diagnostic efficacy. CONCLUSION: (18)F-FDG PET can replace CWU in primary M staging of nonkeratinizing NPC.  相似文献   
72.

Introduction  

Procalcitonin (PCT) has been proposed as a marker of infection in critically ill patients; its level is related to the severity of infection. We evaluated the value of PCT as a marker of bacterial infection for emergency department patients.  相似文献   
73.
74.
75.
76.
Aim: The prognosis of patients with disseminated colorectal carcinoma is poor except for those with single organ pulmonary or hepatic metastases. The objective of the present study was to evaluate the result of pulmonary metastasectomy for colorectal secondary and to identify the prognostic factors. Methods: This was a retrospective study of 80 patients who had pulmonary metastasectomy for pulmonary secondary from colorectal carcinoma in Queen Elizabeth Hospital, Hong Kong. Results: The overall 5‐year and 10‐year survival rates of the entire cohort were 42.5% and 35.5%, respectively. High premetastasectomy carcinoembryonic antigen (> 20 μg/dL), short disease‐free interval (< 12 months) and incomplete resection were the independent prognostic factors. Neither the characteristics of the primary colorectal tumour nor the number of metastatic nodules had a significant contribution to the long‐term survival. Six patients underwent second pulmonary metastasectomy and three were still free from tumour recurrence after the second operation. Conclusion: Patients with pulmonary metastases from colorectal carcinoma would benefit from pulmonary metastasectomy. High premetastasectomy carcinoembryonic antigen and short disease‐free interval were negative predictive factors for survival. Long‐term follow‐up study is required, as recurrence can occur more than 5 years after pulmonary metastasectomy. Also, whether the survival benefit is due to surgical treatment effect or lead‐time bias remains undecided.  相似文献   
77.
78.
BACKGROUND: Sleeve technique is a modified version of crush technique. It is specifically designed to increase the success rate of final kissing balloon inflation, which used to be a major limitation of the latter. OBJECTIVES: The aim of this study was to examine the feasibility, safety, and early clinical outcomes of sleeve technique in stenting different types (de novo, in-stent restenotic or in-stent bifurcation) of coronary bifurcation lesions at different locations. METHODS: From August 2005 to May 2006, 41 consecutive patients with symptomatic, nonleft-main coronary bifurcation stenoses of diameter narrowing >or=50% were treated with two-stent strategy, using sleeve technique. RESULTS: The mean age was 63.6 +/- 11.6 years with male predominance (70.7%). High prevalence of diabetes mellitus (31.7%), total occlusion (22.0%), and multi-vessel disease (65.9%) was observed in this cohort. Intravenous abciximab was given in 35 (85.4%) patients. Final kissing balloon inflation was successfully performed in all patients. The minimal luminal diameter in main vessel and side branch was increased from 0.97 +/- 0.53 mm and 0.81 +/- 0.45 mm to 2.76 +/- 0.34 mm and 2.22 +/- 0.35 mm, respectively. The mean procedure time was only 66.6 +/- 24.6 min. There was one (2.4%) case of subacute stent thrombosis presented as non-Q-wave myocardial infarction at day 3 postprocedure. The resultant in-hospital and 30-day major adverse cardiac event rate were both 2.4%. CONCLUSIONS: Sleeve technique is a feasible and efficient approach in stenting of coronary bifurcation stenoses.  相似文献   
79.
This paper describes experience in a modern district general hospital with a small desktop system for computer-aided diagnosis of acute abdominal pain, over a 12-year period involving 5512 cases. When compared with a baseline year (1973) in which unaided performance was monitored, during an initial study period (1974-76) the diagnostic accuracy of junior staff rose by between 10 and 15%. This higher performance level was then maintained for a decade (1976-86) despite changes in staff. The perforation rate among appendicitis cases fell from 27% to 12.5%, accompanied by a smaller fall in negative laparotomy rates. The saving in surgical bednights devoted to acute abdominal pain was approximately 15%, and the notional cost of resources saved during the first 6 years of operation was 120,000 pounds. Other hospitals have shown--in the short term--benefits similar to those obtained at Airedale District General Hospital. The long-term benefits of the system at Airedale reinforce the conclusions of the earlier short-term trials that a comparable system should probably be offered to all DGHs in the UK, not as an exercise in 'artificial intelligence' but as an effective continuing stimulus to good clinical practice.  相似文献   
80.
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