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   7184篇
  免费   606篇
  国内免费   7篇
耳鼻咽喉   90篇
儿科学   220篇
妇产科学   198篇
基础医学   904篇
口腔科学   120篇
临床医学   817篇
内科学   1501篇
皮肤病学   48篇
神经病学   745篇
特种医学   174篇
外科学   830篇
综合类   156篇
一般理论   11篇
预防医学   938篇
眼科学   134篇
药学   540篇
中国医学   3篇
肿瘤学   368篇
  2023年   63篇
  2022年   110篇
  2021年   233篇
  2020年   154篇
  2019年   225篇
  2018年   249篇
  2017年   191篇
  2016年   203篇
  2015年   210篇
  2014年   300篇
  2013年   433篇
  2012年   552篇
  2011年   555篇
  2010年   253篇
  2009年   234篇
  2008年   374篇
  2007年   363篇
  2006年   342篇
  2005年   329篇
  2004年   238篇
  2003年   273篇
  2002年   231篇
  2001年   109篇
  2000年   92篇
  1999年   107篇
  1998年   74篇
  1997年   44篇
  1996年   55篇
  1995年   58篇
  1994年   53篇
  1993年   35篇
  1992年   67篇
  1991年   69篇
  1990年   52篇
  1989年   66篇
  1988年   53篇
  1987年   54篇
  1986年   47篇
  1985年   36篇
  1984年   40篇
  1983年   32篇
  1982年   31篇
  1981年   29篇
  1979年   34篇
  1978年   34篇
  1977年   26篇
  1976年   32篇
  1974年   30篇
  1972年   33篇
  1967年   30篇
排序方式: 共有7797条查询结果,搜索用时 156 毫秒
71.
The study evaluated a multifaceted educational intervention systematically designed to increase physician involvement in cholesterol-lowering practices. We hypothesized that knowledge, perceptions and behaviours would be enhanced in participating physicians, compared with controls. Method: Fifty-one family physicians were assigned randomly to three groups; the two experimental groups attended a training workshop, received physician and patient education materials and ongoing consultant support. One experimental group also received a “cuing” intervention. The control group received no interventions. Outcome measures included knowledge and attitude scores, self-efficacy perceptions, and physician dietary counselling behaviour. Measures were taken at pretest, 6 weeks and 15 months later. Results: Intervention group physicians achieved significantly higher knowledge scores than the control group at the six-week test; the differences disappeared at 15 months. Attitudes, self-reported practices and overall self-efficacy scores were similar across groups. Within group variation was highly significant. Physician dietary counselling scores were significantly higher in the intervention groups (p = 0.0001). Some associations were seen among knowledge, attitude, self-efficacy and dietary counselling scores. Conclusion: Physician behaviour change in cholesterol reduction may not depend entirely upon knowledge, attitudes and perceptions. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
72.
Intermittent administration of PTH has been found to be an effective anabolic agent in cancellous bone. We have reported previously that combined treatment with PTH and estrogen in estrogen-deficient rats was beneficial in correcting established osteopenia. To determine if the beneficial effects of PTH therapy can be preserved by estrogen alone and whether PTH therapy can be effective in treating osteopenic subjects stabilized with estrogen, we have undertaken a "crossover" study in the rat model of estrogen-deficiency induced osteopenia. Six-month-old female rats were ovariectomized and after 5 wk treated for 8 wk with vehicle, 30 micrograms/kg per day of rPTH(1-34) plus 15 micrograms/kg per day of 17 beta-estradiol or 17 beta-estradiol alone. One group from each treatment regimen was then sacrificed and for an additional 8 weeks the remaining rats were (a) maintained on their previous treatment; (b) "crossed over" to their reciprocal treatment; or (c) administered vehicle only. At the end of this second 8-wk treatment period all rats were sacrificed. Bone mineral density of the distal femur, histomorphometric measurements of the proximal tibia and mechanical testing of the distal femur and selected vertebral bodies were performed. Our results demonstrated that (a) the gains in bone mass, trabecular connectivity and mechanical strength induced by PTH can be maintained by estrogen alone, but are reversed when both agents are withdrawn; and (b) rats with established osteopenia, maintained on estrogen treatment alone, can derive the full beneficial effects from the addition of PTH to the treatment at a later date. These data indicate that combined and/or sequential use of antiresorptive and anabolic agents may be a promising approach to the treatment of osteoporosis.  相似文献   
73.
74.
OBJECTIVE: To document the prevalence of same-sex attraction among students in years 10 and 12 in Australian Government high schools and to assess the association between same-sex attraction, binge drinking and drug injection. METHOD: Cross-section survey by anonymous, self-administered questionnaire of 3,387 students in Years 10 and 12 of the Government school system in Australia. RESULTS: Approximately 6% of respondents reported being currently attracted to members of their own sex. Being attracted to members of the same-sex was associated with more frequent binge drinking among boys and girls, and a three- to four-fold increase in the likelihood of reporting injecting drug use both over the lifetime and within the previous 12 months. CONCLUSIONS: Adolescents attracted to members of the same-sex report engaging in elevated levels of health-limiting behaviours. There is an urgent need for further research to document the reasons for this. It is recommended that health promotion activities directed at moderating young people's drug and alcohol practices explicitly acknowledge the over-representation of same-sex attracted young people in their target audience.  相似文献   
75.
OBJECTIVES: To describe return to work (RTW) for motor vehicle accident (MVA) survivors with mild traumatic brain injury (MTBI) and to examine relationships between RTW and injury severity, cognitive impairment, social interaction, discharge disposition, and sociodemographics. DESIGN: Inception cohort assessed within 1 month of injury and at follow-up 6 to 9 months (mean = 7.4) after injury, for comparisons on outcome of RTW. SETTING: Tertiary care center in Toronto (time 1); at home for follow-up. PARTICIPANTS: Fifty patients with MTBI resulting from MVA who were consecutively admitted during a 20-month period ending April 1994. Thirteen of 63 eligible patients refused consent or were lost to follow-up. Mean age was 31; 62% were men. Eligibility criteria: (1) patients had been working; (2) they had no history of head injury, neurologic disease, or psychiatric illness requiring hospitalization; and (3) they had no catastrophic impairment from accident. MAIN OUTCOME MEASURE: Return to work (at premorbid or modified level). RESULTS: Of the 42% who returned to work, 12% resumed their premorbid level of employment and 30% returned to modified work. There were significant differences (p<.05) between the groups in level of social interaction, premorbid occupation, and discharge disposition. On one test of cognitive functioning the difference was at p = .06. CONCLUSION: Social interaction, jobs with greater decision-making latitude, and discharge home were positively related to RTW for this population. Cognitive impairment within the first month was not a reliable indicator of RTW potential.  相似文献   
76.
77.
1 Incubation of human eosinophils in BSA-coated tissue culture plates resulted in time-dependent adhesion and attendant activation of the NADPH oxidase that were both inhibited (by >85%) by blocking antibodies raised against CD11b and CD18. 2 SB 203580, an inhibitor of p38 mitogen-activated protein (MAP) kinase, did not influence adhesion but inhibited superoxide anion generation (pIC50=-6.57). 3 PP1, an inhibitor of the src-family of protein tyrosine kinases, inhibited adhesion and CD11b/CD18-mediated superoxide anion generation with similar potencies (pEC50s=-5.53 and -5.99 respectively) suggesting that inhibition of the NADPH oxidase was a direct consequence of blocking adhesion. 4 The protein kinase C (PKC) inhibitors Ro-31 8220 (broad spectrum inhibitor), GF 109203X (inhibitor of conventional and novel isoforms) and G? 6976 (inhibitor of conventional isoforms) suppressed adhesion-dependent NADPH oxidase activation (pIC50s=-6.61, -6.05 and -4.89 respectively) without affecting adhesion. Based upon the selectivity of these drugs PKCdelta and PKCepsilon are implicated in the suppression of oxidant production. 5 Wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PtdIns 3-kinase), abolished superoxide anion production in adherent eosinophils (pEC50=-9.06). Similarly, CD11b/CD18-dependent adhesion was suppressed with the same potency (pEC50=-9.29) although the maximum effect did not exceed 50% implying that wortmannin also had an affect on those processes that govern adhesion-driven oxidase activation. 6 PD 098059 and piceatannol, inhibitors of MAP kinase kinase-1 and the syk tyrosine kinase respectively, had no effect on CD11b/CD18-mediated adhesion or NADPH oxidase activation. 7 The results of this study demonstrate that human eosinophils adhere to BSA-coated plastic by a CD11b/CD18-dependent mechanism, which is responsible for activation of the NADPH oxidase. Although the signalling pathway(s) utilized by CD11b/CD18 is still to be elucidated, the data presented herein implicate p38 MAP kinase, novel PKCs and PtdIns 3-kinase.  相似文献   
78.
This article describes the evolving role of echocardiography for the detection and evaluation of thoracic aortic aneurysms. A brief summary of the clinical, anatomical, and pathological features of the etiologic categories of thoracic aneurysms is presented. The advantages and limitations of echocardiography and its comparison with other techniques (computed tomographic scanning, magnetic resonance imaging, and aortography) are discussed.  相似文献   
79.
80.
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