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   21534篇
  免费   1094篇
  国内免费   132篇
耳鼻咽喉   314篇
儿科学   461篇
妇产科学   375篇
基础医学   2963篇
口腔科学   1516篇
临床医学   1621篇
内科学   5405篇
皮肤病学   383篇
神经病学   1802篇
特种医学   539篇
外科学   3143篇
综合类   66篇
一般理论   5篇
预防医学   1357篇
眼科学   355篇
药学   1097篇
中国医学   96篇
肿瘤学   1262篇
  2023年   140篇
  2022年   201篇
  2021年   634篇
  2020年   437篇
  2019年   496篇
  2018年   687篇
  2017年   430篇
  2016年   530篇
  2015年   705篇
  2014年   966篇
  2013年   1121篇
  2012年   1793篇
  2011年   1924篇
  2010年   1065篇
  2009年   909篇
  2008年   1549篇
  2007年   1591篇
  2006年   1472篇
  2005年   1350篇
  2004年   1236篇
  2003年   1008篇
  2002年   942篇
  2001年   132篇
  2000年   112篇
  1999年   131篇
  1998年   144篇
  1997年   120篇
  1996年   118篇
  1995年   91篇
  1994年   80篇
  1993年   67篇
  1992年   59篇
  1991年   62篇
  1990年   42篇
  1989年   41篇
  1988年   29篇
  1987年   25篇
  1986年   26篇
  1985年   26篇
  1984年   42篇
  1983年   36篇
  1982年   25篇
  1981年   26篇
  1980年   17篇
  1979年   11篇
  1978年   12篇
  1977年   15篇
  1976年   13篇
  1975年   11篇
  1974年   12篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
1.
2.
3.
4.
5.
Objective: Polyunsaturated fatty acids n-3 (PUFA n-3) have shown effects in reducing tumor growth, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) abundantly present in fish oil (FO). When these fatty acids are provided in the diet, they alter the functions of the cells, particularly in tumor and immune cells. However, the effects of α-linolenic fatty acid (ALA), which is the precursor of EPA and DHA, are controversial. Thus, our objective was to test the effect of this parental fatty acid. Methods: Non-tumor-bearing and tumor-bearing Wistar rats (70 days) were supplemented with 1 g/kg body weight of FO or Oro Inca® (OI) oil (rich in ALA). Immune cells function, proliferation, cytokine production, and subpopulation profile were evaluated. Results: We have shown that innate immune cells enhanced phagocytosis capacity, and increased processing and elimination of antigens. Moreover, there was a decrease in production of pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6)) by macrophages. Lymphocytes showed decreased proliferation capacity, increased cluster of differentiation 8 (CD8+) subpopulation, and increased TNF-α production. Conclusions: Oil rich in ALA caused similar immune modulation in cancer when compared with FO.  相似文献   
6.
7.
8.
9.
Die Anaesthesiologie - Simulationstraining ist für die Notfallmedizin unverzichtbar, insbesondere in Hinsicht auf eine verbesserte Patientensicherheit. Methoden und Technologien umfassen ein...  相似文献   
10.
Background:Workplace hazards are a significant source of health impairment for workers and of financial losses for firms. EU directives on workers’ health and safety standards significantly contributed to reduce reported occupational injuries, yet the incidence and prevalence of work-related mental illness is still very high.Objectives:We investigated the association between work-related hazards and individuals’ perceived mental health. We reviewed the existing evidence on the channels through which task-related factors, adverse agents and psychosocial factors are expected to affect workers’ health, with specific regard to mental health.Methods:We used data from the fifth wave of the European Working Conditions Survey, covering over 40,000 face-to-face interviews with workers in 34 countries, which includes information on socio-demographic characteristics, firms and jobs attributes, employment status, as well as working conditions and health status. We carried out an empirical analysis with multivariate regression models in order to estimate the relationship between workers’ mental health problems and workplace risk factors.Results:21,020 interviews were used in the multivariate analysis. We found strong correlations between hazards and various indicators of mental health. Among hazardous agents, low temperatures (β=0.0287) and contact with infectious materials (β=0.0394) were positively associated with mental health outcomes. Among task/sequence-related factors, tiring or painful positions (β=0.0713), repetitive hand/arm movements (β=0.0255), working with VDUs (β=0.0301), repetitive tasks <10 min (β=0.0859) and working in evenings (β=0.00754) were positively associated with mental health. Various psychosocial risk factors related to both the content of the job (for example, frequent disruptive interruptions: β=0.219, working in free time: β=0.0759, poor work-life balance: β=0.228) as well as the job context (for example, bad employment prospects: β=0.177, low decisional autonomy: β=0.245, bad social relations: β=0.186, workplace violence: β=0.411) were positively associated with mental health. The main results of the decomposition show that an important contribution to workers’ overall mental distress at work is associated with psychosocial risk factors (up to 60% for depression/anxiety symptoms and sleep disorders), while the contribution of somatic factors is on average lower (up to 20% for overall fatigue).Conclusions:We argue that action is needed to improve workers’ mental well-being, and reduce the economic costs for both the national health system and employers. Regulations and traditional economic measures are unlikely to prove successful in providing adequate standards of primary and secondary preventive measures in the work place without an appropriate and reliable Risk Assessment Procedure.Key words: Work hazards, risk assessment, job content, mental health  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