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   965篇
  免费   38篇
  国内免费   1篇
耳鼻咽喉   16篇
儿科学   27篇
妇产科学   21篇
基础医学   216篇
口腔科学   8篇
临床医学   110篇
内科学   119篇
皮肤病学   13篇
神经病学   79篇
特种医学   63篇
外科学   140篇
综合类   4篇
预防医学   47篇
眼科学   26篇
药学   34篇
肿瘤学   81篇
  2021年   16篇
  2020年   11篇
  2019年   11篇
  2018年   9篇
  2016年   16篇
  2015年   21篇
  2014年   19篇
  2013年   35篇
  2012年   39篇
  2011年   29篇
  2010年   17篇
  2009年   20篇
  2008年   35篇
  2007年   31篇
  2006年   32篇
  2005年   30篇
  2004年   34篇
  2003年   25篇
  2002年   35篇
  2001年   26篇
  2000年   25篇
  1999年   17篇
  1998年   12篇
  1997年   7篇
  1996年   8篇
  1995年   9篇
  1993年   10篇
  1992年   23篇
  1991年   35篇
  1990年   29篇
  1989年   31篇
  1988年   24篇
  1987年   29篇
  1986年   17篇
  1985年   29篇
  1984年   14篇
  1983年   21篇
  1982年   8篇
  1981年   9篇
  1979年   11篇
  1978年   10篇
  1977年   7篇
  1976年   18篇
  1975年   10篇
  1974年   12篇
  1973年   11篇
  1970年   8篇
  1969年   7篇
  1967年   7篇
  1966年   12篇
排序方式: 共有1004条查询结果,搜索用时 46 毫秒
1.
On the basis of experience with the treatment of more than 1,500 patients with post-burn defects, deformities, and trophic ulcers, the authors distinguished types of affection in which the traditional methods are ineffective. These 133 patients were subjected to plasty with ++cutaneo-fascial grafts; the zones of donor areas from which the grafts are taken are determined. Plasty with ++cutaneo-fascial grafts is indicated in defects of the face, deformity of the neck, total adduction contracture of the arm, defect of the breast, and affections of the hand, leg, and foot. Concrete grafts and the site from which they are taken for restoration of certain regions of the body are suggested. ++Cutaneo-fascial grafts make it possible to restore the shape, function, and the skin of the involved region.  相似文献   
2.
3.
Summary Eight men (20–23 years) weight trained 3 days week–1 for 19 weeks. Training sessions consisted of six sets of a leg press exercise (simultaneous hip and knee extension and ankle plantar flexion) on a weight machine, the last three sets with the heaviest weight that could be used for 7–20 repetitions. In comparison to a control group (n = 6) only the trained group increased (P<0.01) weight lifting performance (heaviest weight lifted for one repetition, 29%), and left and right knee extensor cross-sectional area (CAT scanning and computerized planimetry, 11%, P<0.05). In contrast, training caused no increase in maximal voluntary isometric knee extension strength, electrically evoked knee extensor peak twitch torque, and knee extensor motor unit activation (interpolated twitch method). These data indicate that a moderate but significant amount of hypertrophy induced by weight training does not necessarily increase performance in an isometric strength task different from the training task but involving the same muscle group. The failure of evoked twitch torque to increase despite hypertrophy may further indicate that moderate hypertrophy in the early stage of strength training may not necessarily cause an increase in intrinsic muscle force generating capacity.  相似文献   
4.
We evaluated a commercially available polyclonal antibody to 17 beta-estradiol as the basis for an estrogen receptor (ER) assay of breast carcinoma in formalin-fixed paraffin tissues and then compared it with both the ER-ICA antibody in serial paraffin sections and the biochemical assay of corresponding fresh tissue. Using the estradiol antibody, 49 of 50 cases showed some cytoplasmic staining; 38 cases had nuclear staining. Sensitivity and specificity for different proportions of positive nuclear and cytoplasmic staining were calculated using receiver-operator characteristic curves. The optimum correlation with the biochemical assay was obtained with nuclear staining alone. Greater than 30% nuclear positivity as a cut-off point yielded a sensitivity of 76% and a specificity of 82%. The corresponding ER-ICA values in 38 cases yielded a sensitivity of 93% and a specificity of 56%. The methodology for the ER-ICA assay was more technically demanding in paraffin sections than that of the estradiol antibody and considerably more expensive. This study is the first to show that with nuclear staining only, and not cytoplasmic staining, as the parameter of positivity, the immunocytochemical assay of ER with anti-17 beta-estradiol antibody in routinely processed, formalin-fixed, archival material is an accurate and specific method for the determination of the ER status of breast carcinoma.  相似文献   
5.
6.
Detailed data of the stability of external fixation devices are needed by the orthopaedic surgeon to predict successful healing of a fracture. The stability (rigidity, yield and failure criteria) of four half-frame configurations (single, stacked, double and delta) of the original Hoffmann and AO tubular frame have been analysed under four loading conditions: axial compression, torsion, and both AP- and ML-bending. Overall the two systems' rigidities were the same between similar configurations. Both systems' single half-frames were particularly weak; however, as the number of components (rods, pins, clamps, couplings) on the frame increased, the rigidity of the frame increased. The difference in performance between the two systems lies in their yield and failure characteristics. The AO system exhibited excellent failure criteria in all modes of loading, i.e. no configuration failed within the test limits, whereas most Hoffman frames yielded and failed at low loads.  相似文献   
7.
8.
9.
10.
Acquisition of instrumental defense response with pain reinforcement uncertainty (25% reinforcement) induced the development of acquired helplessness in 50% rats. Acquired helplessness is characterized by the absence of responses to conditioned (light) and unconditioned stimuli (pain), minor response of plasma corticosterone to learning, gas markers of circulatory cerebral hypoxia (DA/V pO2 carotid artery/jugular vein), low sensitivity to severe hypobaric conditions, and high resistance of Purkinje cells in the cerebellum. Piracetam improved learning and prevented the development of acquired helplessness. Local changes in cerebral blood flow and energy deficit in neurons responsible for emotional stress during acquired helplessness impair adaptive capacity, but reduce energy consumption and protect neuronal structures.  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