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   23102篇
  免费   2322篇
  国内免费   44篇
耳鼻咽喉   351篇
儿科学   882篇
妇产科学   623篇
基础医学   3693篇
口腔科学   714篇
临床医学   2712篇
内科学   4258篇
皮肤病学   264篇
神经病学   1436篇
特种医学   751篇
外科学   3088篇
综合类   507篇
一般理论   19篇
预防医学   2263篇
眼科学   552篇
药学   1719篇
中国医学   90篇
肿瘤学   1546篇
  2021年   294篇
  2019年   243篇
  2018年   340篇
  2017年   248篇
  2016年   276篇
  2015年   302篇
  2014年   481篇
  2013年   705篇
  2012年   1013篇
  2011年   1056篇
  2010年   620篇
  2009年   479篇
  2008年   938篇
  2007年   978篇
  2006年   964篇
  2005年   950篇
  2004年   934篇
  2003年   887篇
  2002年   858篇
  2001年   765篇
  2000年   714篇
  1999年   707篇
  1998年   276篇
  1997年   260篇
  1996年   239篇
  1995年   230篇
  1994年   217篇
  1992年   542篇
  1991年   513篇
  1990年   468篇
  1989年   443篇
  1988年   445篇
  1987年   421篇
  1986年   406篇
  1985年   417篇
  1984年   311篇
  1983年   286篇
  1982年   209篇
  1979年   305篇
  1978年   247篇
  1977年   208篇
  1974年   257篇
  1973年   248篇
  1972年   213篇
  1971年   226篇
  1970年   238篇
  1969年   241篇
  1968年   228篇
  1967年   237篇
  1966年   244篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
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   
53.
54.
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   
55.
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   
56.
Haemophilus influenzae causing conjunctivitis in day-care children   总被引:1,自引:0,他引:1  
The role of Haemophilus influenzae in acute purulent conjunctivitis was studied during an outbreak among children in day care. Five day-care centers contributed 20 cases and 35 controls. All the children were subjected to culture of the nasopharynx and the eyes. H. influenzae was carried in the nasopharynx of 53% of the children (range between day care centers, 20 to 91%). Of the 20 children with acute conjunctivitis 8 had eye cultures positive for H. influenzae, 2 had Moraxella and the remaining were culture-negative. Ten colonies of H. influenzae were isolated from each positive culture and identified by capsular type, biotype and multi-locus enzyme electrophoresis. All but one of the isolates were nonencapsulated. They belonged to 4 biotypes and 8 electrophoretic types. The same strain was recovered from the eyes and nasopharynx of the symptomatic children, suggesting that the H. influenzae in the eyes originated from the nasopharynx. There was no evidence for spread of the same H. influenzae strains between day-care centers. Even within each center the Haemophilus strains recovered from the eyes varied among the symptomatic children. The in vitro capacity to attach to oropharyngeal epithelial cells was not increased among the H. influenzae recovered from the eyes. The results question if the majority of conjunctivitis cases were caused by H. influenzae and suggested that eyes were colonized with the nasopharyngeal carrier strain rather than infected by an isolate with special virulence for the eye.  相似文献   
57.
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   
58.
59.
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   
60.
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