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   19368篇
  免费   2228篇
  国内免费   54篇
耳鼻咽喉   307篇
儿科学   794篇
妇产科学   521篇
基础医学   2809篇
口腔科学   613篇
临床医学   2417篇
内科学   3795篇
皮肤病学   235篇
神经病学   1109篇
特种医学   772篇
外科学   2714篇
综合类   516篇
一般理论   18篇
预防医学   2020篇
眼科学   393篇
药学   1436篇
中国医学   89篇
肿瘤学   1092篇
  2021年   284篇
  2019年   234篇
  2018年   312篇
  2017年   239篇
  2016年   264篇
  2015年   275篇
  2014年   447篇
  2013年   620篇
  2012年   898篇
  2011年   935篇
  2010年   523篇
  2009年   423篇
  2008年   801篇
  2007年   870篇
  2006年   837篇
  2005年   831篇
  2004年   740篇
  2003年   723篇
  2002年   644篇
  2001年   649篇
  2000年   605篇
  1999年   601篇
  1998年   260篇
  1997年   260篇
  1996年   243篇
  1995年   212篇
  1994年   211篇
  1993年   172篇
  1992年   464篇
  1991年   442篇
  1990年   407篇
  1989年   393篇
  1988年   391篇
  1987年   370篇
  1986年   365篇
  1985年   365篇
  1984年   275篇
  1983年   255篇
  1982年   188篇
  1981年   186篇
  1979年   257篇
  1978年   213篇
  1977年   193篇
  1976年   162篇
  1975年   164篇
  1974年   193篇
  1973年   213篇
  1972年   169篇
  1971年   161篇
  1970年   161篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Analysis of epidermal growth factor receptor (EGFr) and estrogen receptor (ER) was performed on tumor samples from 231 patients with operable breast cancer followed for up to 6 years after surgery. The median duration of follow-up in patients still alive at the time of analysis was 45 months. Thirty-five percent of patients (82) had tumors greater than 10 fmol/mg of 125I-EGF binding (EGFr+) and 47% (109) had cystolic ER concentration greater than 5 fmol/mg (ER+), with a marked inverse relationship between EGFr and ER (P less than .00001). EGFr was second only to axillary-node status as a prognostic marker for all patients in terms of both relapse-free and overall survival in univariate analysis (P less than .001, log-rank EGFr + v EGFr-). For patients with histologically negative axillary nodes, EGFr was superior to ER in predicting relapse and survival (P less than .01 and P less than .005, respectively, compared to P less than .1 and P less than .1, log-rank). In a multivariate (Cox model) analysis, only EGFr--out of EGFr, ER, size, and grade--was predictive for either relapse-free or overall survival for patients with node-negative disease (P = .052 and P = .026, respectively). One hundred eighty-seven case patients in the series were assessed for neu expression immunochemically, and 31 were positive. There was a highly significant increased risk of relapse and death in the positive group. In patients with otherwise good prognostic markers (ER+, node-negative, well-differentiated tumors), neu expression predicted for significantly worsened overall survival.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
63.
64.
Lateral orbitotomy--a review   总被引:2,自引:0,他引:2  
Lateral orbitotomy is the standard surgical approach to lesions in the middle third of the orbit, to many lesions in the posterior third of the orbit and to benign lacrimal gland tumours. The indications, surgical technique and complications are discussed.  相似文献   
65.
OBJECTIVES: to evaluate the Saville and Holdsworth Occupational Personality Questionnaire (OPQ) to assess its potential and validity as a tool in the recruitment of doctors. To determine the range of personality characteristics in a group of general practitioners. DESIGN: an administered commercially available questionnaire. SETTING: general practitioners in North and Mid. Stafftordshire. SUBJECTS: 133 general practitioners or trainees. RESULTS: 44% of general practitioners agreed to participate. The majority found it useful and recognised its potential to increase self-awareness, highlight weaknesses that might be improved and for future recruitment of others to their teams. Doctors' personality traits were similar to those of managerial/professional norms. The validity of the OPQ was supported by (a) significant associations with subjects' previously reported mental health problems and (b) 83% of respondents confirming that their reports correctly described their personalities at work. CONCLUSIONS: OPQs have a place in the recruitment of doctors by identifying appropriate people to strengthen the team.  相似文献   
66.
Flow-independent angiography (FIA), an approach that isolates arterial blood using MR relaxation characteristics rather than flow effects, was evaluated for application in peripheral vascular disease (PVD). First, pilot studies were conducted in which FIA coronal projection images were obtained from controls and symptomatic patients with PVD to assess clinical utility. All control images corresponded to the expected leg arterial anatomy with little interference from deep veins (one of five) and muscle (zero of five). Superficial venous signal was less well suppressed in comparison to deep veins (four of five). Images of symptomatic patients were less consistent with difficulty suppressing muscle and deep venous signal in some cases and edema when present. We then compared T2 values for muscle (T2m, tibialis anterior), arterial blood (femoral and popliteal arteries), and venous blood (femoral, popliteal, and saphenous veins) in controls (n = 8) and symptomatic patients with intermittent claudication (n = 5) or ischemic rest pain (n = 7). Changes in T2 measurements of various tissues accounted for poorer contrast in symptomatic patients. Patients with ischemic rest pain had significantly higher T2m compared with controls (T2m = 39.3 ± 2.1 (1 standard error of the mean [SEM]) versus 30.9 ± .4, P < .01). For all measurements, other than saphenous vein, variances were greater in symptomatic patients. To realize the inherent advantages of FIA for this clinical application, additional work on suppression of signals from muscle, veins, and edema is required. One promising approach involves shifting from projection images to three-dimensional acquisitions for improved tissue suppression.  相似文献   
67.
68.
The purpose of this investigation was to examine the morphologic and histochemical characteristics of paraspinal muscles in patients with scoliosis after long-term electrical stimulation. Thirty-six children with idiopathic scoliosis, who had been treated with implantable muscle stimulators, had paraspinal muscle biopsies at the time of implantable muscle stimulator removal. Group A patients whose curve did not progress, had 2.9 years of stimulation stopped at skeletal maturity, with a further 1.5 years of nonstimulation before implant removal and biopsy. In group B patients, who had an average of 2.3 years of stimulation, the curve progressed and stimulation was continued until fusion and biopsy. Neither group showed any increase in the frequency of pathologic changes of paraspinal muscles contrasted with values reported in the literature for scoliotic muscle. In group A patients there was an increased proportion of type 1 fibers on the convex side of the curve compared to the concavity. Despite this finding the curves did not require fusion, suggesting that the increased percentage of type 1 fibers was not the cause of the scoliosis. In group B patients there was an even higher type 1 concentration on the convex side contrasted to the convex side of group A patients.  相似文献   
69.
70.
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