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   10271篇
  免费   890篇
  国内免费   30篇
耳鼻咽喉   68篇
儿科学   375篇
妇产科学   291篇
基础医学   1360篇
口腔科学   77篇
临床医学   1398篇
内科学   1851篇
皮肤病学   121篇
神经病学   1155篇
特种医学   201篇
外科学   1034篇
综合类   116篇
一般理论   15篇
预防医学   1707篇
眼科学   97篇
药学   769篇
中国医学   3篇
肿瘤学   553篇
  2024年   19篇
  2023年   138篇
  2022年   151篇
  2021年   339篇
  2020年   264篇
  2019年   387篇
  2018年   403篇
  2017年   340篇
  2016年   378篇
  2015年   336篇
  2014年   443篇
  2013年   622篇
  2012年   874篇
  2011年   902篇
  2010年   461篇
  2009年   345篇
  2008年   647篇
  2007年   658篇
  2006年   576篇
  2005年   506篇
  2004年   481篇
  2003年   423篇
  2002年   404篇
  2001年   109篇
  2000年   80篇
  1999年   84篇
  1998年   66篇
  1997年   54篇
  1996年   60篇
  1995年   46篇
  1994年   36篇
  1993年   44篇
  1992年   50篇
  1991年   43篇
  1990年   51篇
  1989年   44篇
  1988年   40篇
  1987年   25篇
  1986年   40篇
  1985年   31篇
  1984年   26篇
  1983年   16篇
  1982年   15篇
  1981年   12篇
  1979年   8篇
  1978年   11篇
  1974年   13篇
  1972年   10篇
  1969年   7篇
  1968年   11篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
101.
102.
Mushroom bodies are higher centers in the brains of insects. Studies on honey bees and species of ants suggest that these centers are particularly prominent in social insects. The present study confirms the presence of large mushroom bodies in five subfamilies of vespid wasps, while at the same time showing significant departures from the mushroom body organization that typifies bees and ants. Although the basic organizational plan of the insect mushroom body into calyces, peduncle, and lobes is maintained, as is the arrangement of axons of intrinsic neurons, the size and arrangements of the vespid mushroom body lobes differ markedly from those known from other Hymenoptera. Furthermore, considerable variation is found both between and within vespid subfamilies. The present results are discussed with respect to current hypotheses about functional attributes of mushroom bodies and the phylogeny of the Vespidae.  相似文献   
103.
BACKGROUND: Early implantation of centrifugal devices in patients with postcardiotomy cardiogenic shock may provide a bridge to recovery and allow subsequent long-term survival. METHODS: Since January 1989, 62 patients were supported with centrifugal pumps because of failure to wean from cardiopulmonary bypass. Indications were postcardiotomy cardiogenic shock (PCCS) (n = 60), bridge to cardiac retransplantation (n = 1), and right ventricular failure (n = 1). Patients' ages ranged from 23 to 78 years; 40 were men (65%), and 22 were women (35%). Twenty-two patients (35%) had a left ventricular assist device; 9 patients (15%) had a right ventricular assist device; and 31 patients (50%) had a biventricular assist device. Length of support ranged from 1 day to 19 days. RESULTS: Forty-two patients (68%) were weaned successfully; 27 patients survived to discharge (44%). Complications included bleeding (n = 41, 66%), renal failure (n = 28, 45%), and respiratory failure (n = 26, 42%). Currently, 23 patients survived 10 or more years (n = 1), 6 to 10 years (n = 7), 1 to 5 years (n = 10), and less than 1 year (n = 5). CONCLUSIONS: Centrifugal pumps are available, easy to use, and relatively inexpensive. Our experience justifies their continued use as a bridge to recovery for patients with postcardiotomy cardiogenic shock, despite the availability and increasing use of more expensive devices.  相似文献   
104.
105.
106.
This paper introduces a novel survey instrument to identify distinct components of nutrition knowledge and test for links between knowledge and dietary choices in Southern Malawi. Our first aim is to distinguish respondents' familiarity with recommended behaviours, such as when to start breastfeeding or introduce solid foods, from respondents' factual knowledge about mechanisms, such as whether biscuits or papaya and orange fruit or orange Fanta contribute more to future health. We find knowledge of nutrition behaviours to be strongly associated with more schooling, older age, and being female, whereas knowledge of mechanisms is associated only with training and employment as a health professional. We then test whether this expanded definition of nutrition knowledge is associated with dietary intake when controlling for other factors and find no significant links in these data. Results point to the need for knowledge surveys and public health behaviour‐change campaigns to address the kinds of information that might have the most influence on actual behaviour, potentially including the mechanisms involved in food composition, food safety, and disease transmission.  相似文献   
107.
Objective: To investigate the prevalence of asthma and mental health problems among representative samples of youth in high-risk service settings and the community, and to examine the relationship between asthma and mental health in these groups. Methods: Data were drawn from the Alternative Service Use Patterns of Youth with Serious Emotional Disturbance Study (SED) (n?=?1181), a combined representative, cross-sectional sample of youth in various clinical settings and the community. Multiple logistic regression analyses were used to examine the association between asthma and mental disorders. Demographic characteristics were investigated as potential confounders. Results: Asthma was common among 15.2% of youth in service settings and 18.8% of youth in the community. The prevalence of mental disorders was extremely high among youth with and without asthma in all service settings, and asthma was associated with increased prevalence of mental disorders among youth in the community, but not among youth in service settings. The relationship between asthma and internalizing disorders among youth in the community does not appear entirely attributable to confounding by demographics. Conclusions: Findings are consistent with and extend previous data by showing that both asthma and mental disorders are disproportionately common among youth in high-risk service settings. Almost half of youth with asthma in service settings meet diagnostic criteria for a mental disorder. Clinicians and policy makers who are responsible for the health care of youth in these high-risk groups should be aware that asthma is common, and that the prevalence of internalizing disorders are especially common among those with asthma.  相似文献   
108.
109.
110.
As a topic of psychoanalytic inquiry, menstruation is surprisingly absent from psychoanalytic literature: menstruation as a part of female psychosexual development is in need of further empirical exploration. The research uses semi‐structured interviews with six young women to explore individual experiences of the menarche and menstruation. The data is analysed using narrative and thematic analysis and interpretations, made within a (broadly classical) psychoanalytic frame, drive the results. In this condensed version of the research, three central findings will be discussed: (1) the role of mother in negotiating the menarche; (2) the difficulty of irregular periods and the fear that something internal has ‘gone wrong’; (3) the link to ideas of mess, dirt and shame, potentially reflective of feelings about sexuality. The research concludes that menstruation is an area worthy of careful psychoanalytic consideration in theory and in clinical practice.  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