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   1468篇
  免费   87篇
  国内免费   6篇
耳鼻咽喉   10篇
儿科学   23篇
妇产科学   9篇
基础医学   230篇
口腔科学   46篇
临床医学   142篇
内科学   358篇
皮肤病学   23篇
神经病学   85篇
特种医学   42篇
外科学   228篇
综合类   13篇
一般理论   1篇
预防医学   94篇
眼科学   47篇
药学   92篇
中国医学   7篇
肿瘤学   111篇
  2023年   12篇
  2022年   36篇
  2021年   52篇
  2020年   36篇
  2019年   44篇
  2018年   58篇
  2017年   34篇
  2016年   54篇
  2015年   51篇
  2014年   61篇
  2013年   84篇
  2012年   114篇
  2011年   139篇
  2010年   59篇
  2009年   61篇
  2008年   73篇
  2007年   66篇
  2006年   55篇
  2005年   55篇
  2004年   62篇
  2003年   47篇
  2002年   46篇
  2001年   16篇
  2000年   23篇
  1999年   18篇
  1998年   8篇
  1997年   8篇
  1996年   7篇
  1995年   5篇
  1994年   4篇
  1993年   6篇
  1992年   11篇
  1991年   11篇
  1990年   10篇
  1989年   8篇
  1988年   7篇
  1987年   10篇
  1986年   11篇
  1985年   7篇
  1984年   5篇
  1983年   14篇
  1982年   9篇
  1981年   7篇
  1980年   4篇
  1979年   9篇
  1978年   8篇
  1977年   8篇
  1974年   3篇
  1973年   4篇
  1972年   4篇
排序方式: 共有1561条查询结果,搜索用时 15 毫秒
1.
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.
There is evidence that epidermal stem cells or their early progeny may be the targets in graft-versus-host disease (GVHD). The early progeny should be a proliferating group of daughter cells more concentrated in areas just above or adjacent to stem cell regions. We have, therefore, compared proliferative rates of keratinocytes within relevant subregions of the epidermis using the AgNOR stain on biopsies from patients with GVHD, non-specific inflammatory infiltrates (NSI) and normal skin. We concurrently evaluated T cell infiltration using immunohistology on paraffin-embedded tissue with UCHL-1 antibody. Fifty-one bone marrow transplant patients were evaluated in each of three temporal groups (days 7-20 post-transplant, days 20-40 post-transplant, and days 80-100 post-transplant). In each of these groups, 5-9 patients with a histological diagnosis of GVHD were compared to similar numbers of patients with a histological diagnosis of non-specific dermatitis.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
5.
Histological features of endothelial and vascular changes seen in cell mediated immune reactions were evaluated in skin biopsies from 44 HLA matched and mismatched recipients of bone marrow transplantation. The mismatched group (n = 24) was further subdivided into 'D-mismatched' (n = 14) and 'AB-mismatched' (n = 10). All patients had clinical grade III and histological grade II graft-versus-host disease (GVHD). Comparison groups consisted of skin biopsies from 10 non-GVHD cases. Histological evidence of endothelial damage including perivascular factor VIII related antigen deposition was assessed and compared between the groups. The results showed that all patients post-transplant had evidence of a non-specific vascular response consisting mainly of a perivascular lymphocytic infiltrate, perivascular oedema and factor VIII related antigen extravasation. However, a significant difference between matched and mismatched patients who developed GVHD was the more frequent observation of perivascular nuclear dust in the HLA mismatched group (p less than 0.01) suggesting a greater degree of endothelial cell damage in these patients.  相似文献   
6.
Cytotoxic lymphocytes are thought to kill target cells by means of potent cytotoxic granules that congregate near the microtubular organizing center and the Golgi apparatus at one pole of the killer cell. We searched for evidence of this type of polarization in 12 lip biopsy specimens from patients with acute and/or chronic graft-vs-host disease (GVHD) compared with two lip specimens from normal individuals. Lymphocytes with such polarization were found in contact with epithelial cells of the squamous mucosa in all 12 cases of GVHD, and cells of the cuboidal minor salivary duct epithelium were found in two of 11 evaluable cases. The data add support to the hypothesis that cytolytic lymphocytes attack epithelial cells in GVHD.  相似文献   
7.
When exposed to proinflammatory mediators, human bronchial epithelial cells (HBECs) upregulate the 'constitutive' adhesion molecule expression and cytokine/chemokine release. We tested whether and to what extent the inhibitory effect of fluticasone propionate on HBECs could involve the 'constitutive' and 'cytokine-induced' proinflammatory functions. Stimulation of the HBECs with interleukin (IL)-4 plus tumour necrosis factor (TNF)-alpha was more effective in upregulating intercellular adhesion molecule (ICAM)-1 ( approximately 2.2-fold increase) than vascular adhesion molecule (VCAM)-1 ( approximately 1.6-fold increase) expression (P<0.05) and in increasing the release of 'regulated on activation normal T cell expressed' (RANTES, 5.7-fold increase) than of IL-8 (3.5-fold increase) and granulocyte macrophage-colony stimulating factor (GM-CSF, 2.8-fold increase), (P<0.01). Fluticasone propionate, at the two concentrations tested (10 and 100 nM), was more effective in inhibiting the 'IL-4 plus TNF-alpha-induced' ICAM-1 expression than VCAM-1 expression (P<0.05) and in downregulating RANTES than IL-8 or GM-CSF secretion (P<0.05). The degree of inhibition demonstrated by fluticasone propionate appeared to be related to the degree of cell activation. In addition, for both adhesion molecules, the effect of fluticasone propionate at both concentrations tested appeared to be related to a complete inhibition of 'IL-4 plus TNF-alpha-induced' expression with no involvement of the 'constitutive' expression. Slightly different results were observed for cytokine/chemokine release. Indeed, evaluating RANTES, a complete inhibition of the 'IL-4 plus TNF-alpha-induced' release with a partial inhibition also of the 'constitutive' release at both concentrations of the drug tested was found, whereas for GM-CSF and IL-8, only a partial inhibition of the 'IL-4 plus TNF-alpha-induced' release in the presence of fluticasone propionate 10 and 100 nM. Thus, HBECs can constitutively or upon activation express adhesion molecules and secrete proinflammatory proteins at various levels and the different ability of fluticasone propionate to modulate the HBEC functions appears to be mostly related to the different inhibition of the various 'IL-4 plus TNF-alpha-induced' responses.  相似文献   
8.
Effect of postactivation potentiation on dynamic knee extension performance   总被引:1,自引:0,他引:1  
Six men and four women performed, in separate trials, maximal dynamic knee extensions with loads of 15%, 30%, 45% and 60% of maximal isometric knee extension peak torque (MVC). The dynamic extensions were done after postactivation potentiation (PAP) had been induced with a 10-s MVC, and in a control trial without PAP. PAP, measured as the increase in evoked twitch torque, was 53 (4)% (SE) and 43 (3)% at the time of the first and second extensions with each load. PAP failed to increase the attained peak velocity with any load; on the contrary, there was a trend for peak velocity to decrease in the first extension, which occurred ≅15 s after the 10-s MVC. The results suggest that fatigue produced by the 10-s MVC suppressed any benefit that could be derived from the induced PAP. A surface electromyogram (EMG) recorded from one muscle of quadriceps femoris gave no indication of activation failure in the first knee extension; however, activation impairment specific to the rate of force development cannot be ruled out. It is concluded that the strategy employed, namely of having knee extensions performed soon after the 10-s MVC to maximize PAP at the time of performance, was unsuccessful because there had been insufficient time for recovery from fatigue. It is possible that a longer recovery time, even at the cost of a diminished PAP, may have proved beneficial. Accepted: 27 July 2000  相似文献   
9.
Women health workers have made great contributions to the health of their community for many years. In India, women physicians have established some hospitals, e.g., Christian Medical Colleges in Ludhiana and Vellore. Some such hospitals operate in remote areas to serve the poor and the suffering. Women health workers of Jamkhed, Deen Bandhu of Pachod, have proved that village women can improve the health status of their community, particularly that of women and children, if they receive encouragement to learn health care skills In India, community health care lies mainly with women (e.g., nursing personnel and in rural areas). Yet, despite their competence and experience, few become physicians, health project directors, and administrators because the society continues to be patriarchal and discriminates against females. Women need to become empowered to ensure equal opportunities for training and promotion and equal wages for equal work. In Bangladesh, use of bicycles to visit houses allows women paramedical workers from Gonasasthya Kendra, Sawar, freedom and imparts confidence. People must identify customs, practices, laws, attitudes, religious misrepresentations, and policies that discriminate against women and then oppose them. They should set these changes in motion at home, in villages, and from district to national, and even global levels. In India, society blames the mother for having a girl, but the man donates the chromosome determining sex. In Gandhigram, a woman physician and her peers have effected an apparent change in attitude toward the birth of a girl. Now the people confer equal happiness to her birth as they do to a boy's birth. Yet, female infanticides still occur in some villages of Salem District of Tamil Nadu. Sex determination tests often lead to abortion of female fetuses. Once a woman marries she has no right to her maternal home and often suffers from domestic violence. Many people resist legislation to grant women more rights, e.g., property rights. Various media promote women's empowerment.  相似文献   
10.
Anderson Area Medical Center instituted continuous quality improvement (CQI) hospitalwide two years ago. Three teams were challenged with identifying and improving processes related to accounts receivable. X-ray report turn-around-time, and emergency department patient satisfaction. Nursing participation was sought for all three teams. An eight-step CQI process was used to identify, analyze, and improve these three processes. Substantial nursing participation in these pilot CQI teams led to further participation in many other CQI teams optimizing clinical processes. Nursing personnel gained opportunities to make significant contributions to the enhancement of clinical and administrative processes in a large hospital. Nurses learned to work with other members of the health care team outside of their traditional domains, and this, combined with formalized training in the team process, is empowering.  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