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   989234篇
  免费   70877篇
  国内免费   2673篇
耳鼻咽喉   13549篇
儿科学   25769篇
妇产科学   24241篇
基础医学   141270篇
口腔科学   29513篇
临床医学   85788篇
内科学   194611篇
皮肤病学   20421篇
神经病学   76894篇
特种医学   38962篇
外国民族医学   95篇
外科学   159312篇
综合类   21458篇
现状与发展   2篇
一般理论   243篇
预防医学   65807篇
眼科学   22539篇
药学   77389篇
  9篇
中国医学   3118篇
肿瘤学   61794篇
  2019年   7046篇
  2018年   10430篇
  2017年   8156篇
  2016年   8875篇
  2015年   10215篇
  2014年   13732篇
  2013年   19773篇
  2012年   27207篇
  2011年   28222篇
  2010年   16763篇
  2009年   15871篇
  2008年   27124篇
  2007年   28362篇
  2006年   28964篇
  2005年   27659篇
  2004年   26534篇
  2003年   25475篇
  2002年   24861篇
  2001年   57417篇
  2000年   59224篇
  1999年   49264篇
  1998年   11634篇
  1997年   10140篇
  1996年   10080篇
  1995年   9342篇
  1994年   8666篇
  1993年   7932篇
  1992年   36810篇
  1991年   35097篇
  1990年   33824篇
  1989年   33015篇
  1988年   30098篇
  1987年   29234篇
  1986年   27223篇
  1985年   26007篇
  1984年   18392篇
  1983年   15591篇
  1982年   8065篇
  1979年   16155篇
  1978年   10777篇
  1977年   9243篇
  1976年   8045篇
  1975年   8796篇
  1974年   10666篇
  1973年   10032篇
  1972年   9560篇
  1971年   9007篇
  1970年   8594篇
  1969年   8070篇
  1968年   7353篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
91.
92.
To investigate the role of cell-mediated immunity (CMI) in glomerulonephritis (GN), we identified the infiltrating immune cells both within the glomerulus and in the interstitium. Frozen sections from 103 patients with various forms of GN: 10 with minor glomerular abnormality (MGA) as control, 10 with minimal change nephrotic syndrome (MCNS), 10 with membranous nephropathy (MN), 9 with focal glomerulosclerosis (FGS), 30 with IgA nephropathy (IgAN), 22 with acute post streptococcal glomerulonephritis (APSGN), and 2 with rapidly progressive glomerulonephritis (RPGN) were examined using monoclonal antibodies (MoAb) by indirect immunoalkaline-phosphatase labelling. In most glomerulonephritis, monocyte/M phi and helper/inducer T cells were predominantly infiltrating in the interstitium, but intraglomerular infiltration was rare, except for APSGN. This interstitial infiltration increased proportionally to the level of serum creatinine, and was most prominent in RPGN. Apparently different distribution was seen in APSGN, that is, prominent increase in total number of intra-glomerular monocyte/M phi infiltration with slightly increased T cells. The change was correlated with time after onset; namely the more leucocytic infiltration was observed when the tissue was taken earlier. These data suggest that in APSGN, monocyte/M phi accumulate in glomeruli via cell mediated immunity in addition to humoral immune mechanism resulting in glomerular hypercellularity, whereas in most chronic glomerulonephritis interstitial leucocyte infiltration, particularly helper T cells and monocyte/M phi may play an important role in the progression of glomerulonephritis.  相似文献   
93.
Free-floating clots of the extracranial internal carotid artery are generally considered as surgical emergencies. This retrospective study analyzes six free-floating clots diagnosed by arteriography. Three of these patients had a fixed stroke while the other three had an evolving stroke. Three patients had antecedent ocular or hemispheric transient ischemic attacks. The causes of free-floating clots in the internal carotid artery were atheromatous stenosis in two cases, ulcerated plaque in three cases, and carotid artery dissection in one. All six patients were seen late, approximately 15 hours after their neurologic accident. They were treated with intravenous heparin over a two to five week period. Repeat arteriograms demonstrated complete clot lysis in four instances, while partial lysis was seen in one case. Moderate extension of thrombus occurred in one case only. No further neurologic complications were noted during the treatment by heparin. As indicated by follow-up arteriographic findings, secondary surgery was performed for major carotid lesions and residual clots in five cases. The free-floating thrombus syndrome of the carotid artery should not be considered as a surgical emergency when discovered late in the wake of an acute neurologic accident.  相似文献   
94.
The amount of endothelial cell loss that occurs to the donor cornea during the trephination process was evaluated in 40 porcine eyes. A vital staining technique (alizarin red S and acid violet 19) was used to quantify the extent of endothelial damage and removal. Two types of corneal punches (Weck and H&I0 were used for trephination. The average amount of endothelial loss from the peripheral cornea was 7.9%, accounting for only a 3% loss of endothelial cells over the total surface area of the corneal button. a comparison of the Weck and H&I corneal punches showed no significant difference (P greater than 0.1) by Student's test for both endothelial cell damage and removal.  相似文献   
95.
Multicentricity of hepatocellular carcinoma (HCC) is considered, especially in patients with liver cirrhosis. This paper describes an operative case of a male patient with probable multicentric development of HCC in precirrhotic fibrosis. The main tumors inside the capsule were completely necrotic due to transarterial embolization (TAE). Histologic examination disclosed discrete tiny nodules of HCC that were not detected grossly. They showed highly differentiated trabecular arrangements: Edmondson I. A scirrhous type was noted in the center of the tumors. At the borders of the tumors the carcinoma cells exhibited replacing growth patterns and it was thought that they developed multicentrically. Partial resection must be performed as extensively as possible in a case such as the present one.  相似文献   
96.
97.
98.
Vibrio cholerae was isolated from the blood cultures of a neutropenic patient treated with chemotherapy for non-small-cell lung cancer. Attempts to isolate Vibrio spp. from a rectal swab and stool were unsuccessful. Piperacillin/tazobactam treatment resulted in eradication of the microorganism from the patient's blood. Although Vibrio spp. have occasionally been the source of infection in immunocompromised patients, this report describes the first case of non-0:1 Vibrio cholerae bacteremia in a neutropenic patient with a solid tumour. Electronic Publication  相似文献   
99.
PURPOSE: To compare, using a prospective, randomized controlled study, three methods of teaching a medical school parasitology course: computer-based instruction, traditional lecture-based instruction, and a combination of computer-based and lecture-based instruction. METHOD: A single class of the University of Utah School of Medicine was randomized into three study groups for the second-year parasitology course. The computer group (n = 29) used a locally developed interactive parasitology computer program; the lecture group (n = 32) had traditional lectures, and the combined group (n = 33) used both the computer program and lectures. Students' knowledge was assessed using a pretest, a final examination, and a posttest administered four months after the course. Students also used logs to track the amounts of time they spent studying. Their impressions and course evaluations were collected using a standardized course-evaluation form. RESULTS: The groups' scores on the pretest, final examination, and posttest were not statistically significantly different. Students in the computer group averaged 26.8 hours of studying over the two-week course compared with 32.1 hours in the lecture group and 32.7 hours in the combined group. The difference in study times between the computer and combined groups yielded a significant p value of 0.036. Students were generally positive about the course and the computer program. CONCLUSION: Students can learn parasitology from computer-based instruction as effectively as from traditional lecture-based instruction, and they can do so in less time.  相似文献   
100.
Lithium treatment of chronic hair pulling   总被引:3,自引:0,他引:3  
Ten patients with chronic hair pulling received trials of lithium carbonate of 2 to 14 months' duration. Eight patients demonstrated decreased hair pulling and mild to marked hair regrowth. Three responders experienced increased hair pulling subsequent to discontinuation of lithium treatment. Lithium's effect on hair pulling may be related to its observed benefits in treating aggressivity, impulsivity, and mood instability.  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