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   2057538篇
  免费   148415篇
  国内免费   6125篇
耳鼻咽喉   27406篇
儿科学   66867篇
妇产科学   57645篇
基础医学   298190篇
口腔科学   56604篇
临床医学   190493篇
内科学   400598篇
皮肤病学   41747篇
神经病学   168996篇
特种医学   77373篇
外国民族医学   672篇
外科学   299342篇
综合类   44964篇
现状与发展   1篇
一般理论   699篇
预防医学   167371篇
眼科学   46300篇
药学   149819篇
  6篇
中国医学   4534篇
肿瘤学   112451篇
  2019年   16590篇
  2018年   23205篇
  2017年   17774篇
  2016年   19293篇
  2015年   21957篇
  2014年   30622篇
  2013年   47392篇
  2012年   64624篇
  2011年   68840篇
  2010年   40452篇
  2009年   37733篇
  2008年   63677篇
  2007年   67508篇
  2006年   67659篇
  2005年   65823篇
  2004年   62768篇
  2003年   60096篇
  2002年   58772篇
  2001年   91293篇
  2000年   94006篇
  1999年   79424篇
  1998年   22663篇
  1997年   20594篇
  1996年   20304篇
  1995年   19171篇
  1994年   18066篇
  1993年   17033篇
  1992年   63109篇
  1991年   61453篇
  1990年   59771篇
  1989年   57073篇
  1988年   52940篇
  1987年   51826篇
  1986年   49489篇
  1985年   47363篇
  1984年   35757篇
  1983年   30397篇
  1982年   18439篇
  1979年   32683篇
  1978年   23155篇
  1977年   19243篇
  1976年   18668篇
  1975年   19576篇
  1974年   23744篇
  1973年   23037篇
  1972年   21525篇
  1971年   19966篇
  1970年   18756篇
  1969年   17314篇
  1968年   16534篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
We report a case of intestinal obstruction in a 73-year-old woman caused by ileocolic intussusception. The underlying cause was a giant submucosal ulcerating lipoma (6?×?3.3?×?3.8 cm) extending from the superior mucosal lip of Bauhin’s valve. Abdominal ultrasonography showed a pathognomonic target-like mass appearing as multiple concentric rings. CT scan confirmed the diagnosis. Because of apparent obstruction, a laparotomy with right hemicolectomy and ileocolic anastomosis was performed. Lipomas most frequently occur in the cecum and ascending colon where they represent the most common submucosal mesenchymal tumor. They typically occur in elderly women with an incidence that varies from 0.15 to 0.56 %. Pain, rectal bleeding, and obstruction are typical symptoms. When faced with an intussusception in children, reduction with air per rectum can be performed. In adults, however, malignant cell spreading and seeding is of big concern. Since approximately 20–50 % of all underlying causes are malignant, explorative surgery is favored in adults.  相似文献   
64.
65.
66.
67.
68.
This study explored the relationship between active mediation, exposure to Daniel Tiger’s Neighborhood, and key indicators of preschoolers’ social and emotional development. One hundred and twenty-seven children aged 2–6 either watched or did not watch 10 episodes of Daniel Tiger’s Neighborhood over a two-week period. Results revealed that preschoolers who watched the program exhibited higher levels of empathy, self-efficacy, and emotion recognition when their regular TV-watching experiences are frequently accompanied by active mediation. This was especially true for younger preschoolers and preschoolers from low-income families. Implications for policy-makers, parents, producers of prosocial programming, and educators are discussed.  相似文献   
69.
Objectives: The steeling effect suggests that early-life adversity can have a beneficial impact later in life. However, little is known about its underlying mechanisms and long-term outcomes . The study aimed to examine the role of early-life adversity (ELA) on successful aging, and whether this relationship can be explained by mental and physical health.

Method: Socio-demographics, early-life adversity (ELA), individual quality of life (iQoL), and mental and physical health of 270 individuals (Mage = 66.82 years, 71.5% female) were assessed. Polynomial regressions and mediation analyses were conducted.

Results: Significant inverse U-shaped associations were found between ELA and iQoL (β = ?.59, p = .005) and between ELA and mental health (β = ?.64, p = .002), but not between ELA and physical health. Furthermore, mental health significantly mediated the relationship between ELA and iQoL (b = ?.84, BCa CI [?1.66, ?.27]).

Conclusion: Highest level of individual quality of life (i.e. successful aging) was related to a moderate amount of ELA. Additionally, mental health significantly mediated this relationship. These findings suggest that some amount of ELA could be beneficial for successful aging. Resource-focused interventions are needed to improve health and promote successful aging for an underdetected, at-risk subgroup with low early-life adversity.  相似文献   

70.
At this study a multi-criteria model was developed to examine the available procedures, techniques and methods of handling infectious waste in the large healthcare unit of University Regional General Hospital of Patras, Western Greece. Particularly, this study examined the: a) current legislation and Directives issued for medical waste management at Greece and among the other EU-members, b) contribution of healthcare wastes (HCW) generation rate on social and economic parameters in selected European countries, c) available procedures, techniques, and methods upon the disposal of infectious wastes at the healthcare studied, and, d) propositions for integrated management of such hazardous wastes. Specifically, the Analytic Hierarchy Process (AHP) methodology was applied under pair wise comparison matrices in two stages: 1) the scale factors and the indicators, and 2) the criteria and their sub–criteria. The assessment of these pair wise matrices included the indicators and the sub–criteria. Subsequently, two pair wise comparison matrices, upon a) the “Fulfillment of environmental objectives” indicator and b) the “Energy consumption” sub criterion, were denoted. The AHP methodology yielded good results; however there is still space of improving the environmental performance. The normalized relative weights obtained for the criteria and sub criteria motivated specific actions that have to be handled. Particularly, the results indicated a very good value in environmental management criteria due the values obtained for the commitment towards the environmental policy standards and the waste management procedures. However, further improvements on staff awareness (such as development programs to enhance sensitivity) and more green purchasing suppliers, should be further addressed.  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