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   788篇
  免费   40篇
  国内免费   9篇
耳鼻咽喉   2篇
儿科学   50篇
妇产科学   12篇
基础医学   73篇
口腔科学   13篇
临床医学   62篇
内科学   184篇
皮肤病学   11篇
神经病学   34篇
特种医学   134篇
外科学   123篇
综合类   17篇
预防医学   23篇
眼科学   2篇
药学   47篇
  1篇
中国医学   6篇
肿瘤学   43篇
  2021年   5篇
  2018年   8篇
  2017年   7篇
  2016年   6篇
  2015年   6篇
  2014年   11篇
  2013年   23篇
  2012年   15篇
  2011年   10篇
  2010年   26篇
  2009年   23篇
  2008年   21篇
  2007年   29篇
  2006年   16篇
  2005年   12篇
  2004年   14篇
  2003年   18篇
  2002年   20篇
  2001年   22篇
  2000年   12篇
  1999年   18篇
  1998年   30篇
  1997年   32篇
  1996年   41篇
  1995年   42篇
  1994年   35篇
  1993年   21篇
  1992年   19篇
  1991年   26篇
  1990年   14篇
  1989年   25篇
  1988年   43篇
  1987年   28篇
  1986年   17篇
  1985年   18篇
  1984年   17篇
  1983年   11篇
  1982年   7篇
  1981年   10篇
  1980年   10篇
  1979年   6篇
  1978年   4篇
  1977年   8篇
  1976年   8篇
  1975年   8篇
  1973年   3篇
  1972年   7篇
  1971年   4篇
  1969年   3篇
  1966年   3篇
排序方式: 共有837条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
In situ saphenous vein grafts are being used with increasing frequency for bypass procedures involving the femoral and popliteal arteries. Complications of these procedures include anastomotic stenoses and persistent arteriovenous fistulae that may result in failure of the graft. Balloon angioplasty and embolotherapy with detachable balloons were employed successfully in three or four recent cases of patients with complications from in situ grafts. Tailored angiography is essential for evaluating in situ grafts, and interventional techniques are extremely useful for managing complications.  相似文献   
5.
A comparison of three methods of repairing the hard palate.   总被引:2,自引:0,他引:2  
OBJECTIVE: To compare growth, speech, and nasal symmetry outcomes of three methods of hard palate repair. PATIENTS: Consecutive available records of children born with unilateral bony complete cleft lip and palate over the period 1972 to 1992. INTERVENTIONS: Identical management of lip, nose, alveolus, and soft palate. Hard palate repair by Cuthbert Veau (CV) from 1972 to 1981, von Langenbeck (vL) from 1982 to 1989, or medial Langenbeck (ML) from 1989 to 1991. OUTCOME MEASURES: For growth: GOSLON yardstick or 5-year model index. For speech: articulation test. Nasal anemometry. For nasal symmetry: Coghlan computer-based assessment. All these measures were developed during the period of data collection but not for this project. RESULTS: There was a strong trend toward more favorable anteroposterior maxillary growth with the change from CV to vL to ML techniques. This fell short of statistical significance because of the small sample size. There was a significant reduction in cleft-related articulation faults (p =.01) considered to be related to improved arch form. In the absence of improved rates of velopharyngeal insufficiency or nasal symmetry, increased surgical experience was discounted as a significant contribution to improved growth and articulation outcomes. CONCLUSIONS: Reduced periosteal undermining and residual exposed palatal shelf from CV to vL to ML improved incisor relationships and articulation.  相似文献   
6.
7.
Intestinal schistosomiasis japonica: CT-pathologic correlation   总被引:1,自引:0,他引:1  
  相似文献   
8.
Simple rapid tests for presumptive identification of catalase-negative non-beta-hemolytic cocci (i.e., enterococci, leuconostocs, and pediococci) have not previously been available. Seven hundred thirty-four strains of aerobic and facultatively anaerobic, catalase-negative, non-beta-hemolytic gram-positive cocci were tested for susceptibility to vancomycin (Vans) by a screening procedure and production of leucine aminopeptidase (LAPase) and pyrrolidonylarylamidase (PYRase) in disk tests. Three unique patterns of activity in response to the three disks (30 micrograms of vancomycin, PYRase, and LAPase) can be used to presumptively identify the vancomycin-resistant (Vanr) enterococci (Vanr and PYRase and LAPase positive), leuconostocs (Vanr and PYRase and LAPase negative), and pediococci (Vanr, PYRase negative, and LAPase positive). The results indicate that, together with Gram stain characteristics and the catalase test, the vancomycin, LAPase, and PYRase disk tests can be used to presumptively identify Vanr strains of enterococci as well as Leuconostoc and Pediococcus strains from human infections.  相似文献   
9.
The integrity of sperm DNA is crucial for the maintenance of genetic health. A major source of damage is reactive oxygen species (ROS) generation; therefore, antioxidants may afford protection to sperm DNA. The objectives of the study were, first, to measure the effects of antioxidant supplementation in vitro on endogenous DNA damage in spermatozoa using the single cell gel electrophoresis (comet) assay and, second, to assess the effect of antioxidant supplementation given prior to X-ray irradiation on induced DNA damage. Spermatozoa from 150 patients were prepared by Percoll centrifugation in the presence of ascorbic acid (300, 600 microM), alpha tocopherol (30, 60 microM), urate (200, 400 microM), or acetyl cysteine (5, 10 microM). DNA damage was induced by 30 Gy X-irradiation. DNA strand breakage was measured using the comet assay. Sperm DNA was protected from DNA damage by ascorbic acid (600 microM), alpha tocopherol (30 and 60 microM) and urate (400 microM). These antioxidants provided protection from subsequent DNA damage by X-ray irradiation. In contrast, acetyl cysteine or ascorbate and alpha tocopherol together induced further DNA damage. Supplementation in vitro with the antioxidants ascorbate, urate and alpha tocopherol separately has beneficial effects for sperm DNA integrity.   相似文献   
10.
The immunocytochemical expression of intercellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM-1), endothelial leukocyte adhesion molecule (ELAM-1), endothelial cell adhesion molecule (EndoCAM CD31), and HLA-DR antigens was investigated in sections of 24 reactive lymph nodes and in 15 cases of Hodgkin's disease. ICAM-1 was detected in sinus macrophages, follicular dendritic reticulum cells (FDRCs), interdigitating reticulum cells (IDRCs), epithelioid macrophages, Hodgkin's cells (HCs), and vascular endothelium. ICAM-1 expression was often associated with that of HLA-DR antigens. VCAM-1 was detected in FDRCs, in fibroblast reticulum cells (FRCs), in macrophages, and in rare blood vessels. EndoCAM (CD31) was constitutively expressed in all types of endothelial cells, sinus macrophages, and in epithelioid granulomas. ELAM-1 was selectively expressed by activated endothelial cells of high endothelium venules (HEVs). When expression of the inducible adhesion molecules ICAM-1, VCAM-1 and ELAM-1 was comparatively evaluated in HEVs, it was found that ICAM-1 + HEVs were present in all reactive and HD nodes, whereas ELAM-1 and/or VCAM-1 were expressed only in those pathologic conditions characterized by high levels of interleukin-1/tumor necrosis factor (IL-1/TNF) production, such as granulomatosis and Hodgkin's disease. In Hodgkin's disease, the expression of ELAM-1/VCAM-1 was more pronounced in cases of nodular sclerosis and was associated with a significantly higher content of perivascular neutrophils.  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