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   47332篇
  免费   4367篇
  国内免费   70篇
耳鼻咽喉   616篇
儿科学   1269篇
妇产科学   1320篇
基础医学   6830篇
口腔科学   1257篇
临床医学   5809篇
内科学   8265篇
皮肤病学   601篇
神经病学   3788篇
特种医学   2172篇
外国民族医学   1篇
外科学   6147篇
综合类   869篇
一般理论   23篇
预防医学   5255篇
眼科学   1090篇
药学   3543篇
  3篇
中国医学   56篇
肿瘤学   2855篇
  2021年   655篇
  2019年   638篇
  2018年   745篇
  2017年   622篇
  2016年   615篇
  2015年   713篇
  2014年   938篇
  2013年   1464篇
  2012年   2143篇
  2011年   2221篇
  2010年   1192篇
  2009年   984篇
  2008年   1861篇
  2007年   2008篇
  2006年   2004篇
  2005年   2003篇
  2004年   1818篇
  2003年   1668篇
  2002年   1699篇
  2001年   1598篇
  2000年   1704篇
  1999年   1440篇
  1998年   633篇
  1997年   511篇
  1996年   516篇
  1995年   525篇
  1994年   440篇
  1993年   448篇
  1992年   1255篇
  1991年   1164篇
  1990年   1150篇
  1989年   1077篇
  1988年   1000篇
  1987年   1001篇
  1986年   919篇
  1985年   917篇
  1984年   711篇
  1983年   623篇
  1982年   438篇
  1981年   392篇
  1980年   398篇
  1979年   657篇
  1978年   525篇
  1977年   409篇
  1976年   400篇
  1975年   373篇
  1974年   451篇
  1973年   439篇
  1972年   450篇
  1971年   423篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
A number of vitamin D3 metabolites inhibit benzodiazepine- and dimethyl sulfoxide-induced differentiation of Friend erythroleukemia cells. The inhibition is dose dependent and occurs at nM concentrations. The order of potency of these compounds is 1,25-dihydroxycholecalciferol greater than 1,25,26-trihydroxycholecalciferol greater than 1,24R,25-trihydroxycholecalciferol greater than 1 alpha-hydroxycholecalciferol greater than 24R,25-dihydroxycholecalciferol greater than 25S,26-dihydroxycholecalciferol. The inhibition is maximal when the vitamin D3 analogs are added together with the inducer, and becomes progressively decreased with delayed addition. These results suggest that the vitamin D3 metabolites may play a regulatory role in erythropoiesis.  相似文献   
42.
43.
If proven effective, vaginal microbicides and diaphragms will likely be part of a larger HIV prevention model that includes condoms and other prevention strategies. It is, therefore, important to understand how introducing new prevention methods may affect overall patterns of sexual risk behavior. Data presented were collected as part of a safety and feasibility study of ACIDFORM gel with a diaphragm among 120 women in South Africa. Interviews were administered at enrollment and months 1, 3, 5, and 6 of the trial. Focus groups were conducted at trial exit. Frequency of sex increased significantly after enrollment. This increase appears to be owing to perceived protection from HIV and greater sexual pleasure afforded by the gel. Male condom use was high overall but increased significantly from enrollment. Data suggest this is because of increased partner involvement, increased negotiating power afforded by study participation, and provision of free condoms perceived to be of high quality.  相似文献   
44.
Obsessive-compulsive disorder is increasingly recognized in patients of different age groups. Serotonergic agents, such as clomipramine, have been recently found to be useful in the management of this condition. However, unexpected side effects, such as dysphoria, aggressiveness, and paranoid ideation, may occur with therapeutic doses of this compound, as evidenced in the cases of two male adolescents presented here. Possible pathogenetic factors, involving serotonin and serotonin-receptor abnormalities are discussed. Management of these side effects is based on adequate dose reduction and monitorization.  相似文献   
45.
46.
The following article is an attempt to encapsulate an historical overview of spirituality in nursing. Despite a plethora of information relative to spirituality in nursing, the decision was to do an eclectic overview that was not reflective of any one spiritual/religious group. The authors at times found this goal difficult when writing about the Pre-Christian and Christian eras. Most of the major religions have their own perspective on the concept of spirituality, and historical personalities recorded maybe reflective of that particular religion. Another factor that impacted on the writing of this article was the concept that spirituality was not always linked specifically to religion. Spirituality was an experiential component of the wonders of nature and life, a domain that the authors took into account but did not expound upon. Finally the authors realized that spirituality has almost always been an aspect of African-American life and certainly of those in nursing. To this end the authors realize that there is a need for more research in this area.  相似文献   
47.
48.
Young children's ability to participate in conversation has been of particular interest in the study of pragmatic aspects of language. In this study, topics of conversation were investigated by videotaping 10 dyads of 4-year-old children during play. Ten-minute samples were analyzed according to a number of topic-dependent measures. Results revealed that all dyads evidenced some lengthy topics (13-91 utterances). Longer topics were characterized by three text-level functions. Enacting Scenarios, Describing, and Problem Solving. Nevertheless, three fourths of all dialogues were considered relatively short. Generally, partners contributed equally to dialogue, but in some dyads, 1 child dominated initiation. Findings of the study suggest that 4-year-olds are capable of extended participation in dialogue, at least part of the time. Naturalistic play settings may elicit samples of conversation that are representative of preschoolers' ability.  相似文献   
49.
Cardiovascular intervention for high-risk families: the Heart Smart Program   总被引:2,自引:0,他引:2  
The Heart Smart Family Health Promotion Program is a multidisciplinary, school-based program for cardiovascular risk reduction among high-risk children and their families. As a program that includes young adults at high risk, it is adaptable to a clinical practice. Nineteen fourth and fifth graders were selected as probands for elevated risk factors after a general screening to identify families for an intervention program. Twenty-three parents participated in a 12-week program focused on eating, exercise, and smoking behavior changes enhanced by behavicral support strategies. Weekly sessions were held in the auditorium/cafeteria of the elementary school and consisted of orientation and presentations, cardiovascular (CV) screening with medical feedback, activities, self-monitoring, counseling, and contingency contracting. Information gathered before and after the program included medical history, CV health knowledge and relevant behavior, blood pressure, serum lipid and lipoprotein values, anthropometric measurements, and urine electrolyte excretion. Both children and parents showed positive changes in eating habits and physical activity and significant changes in knowledge and blood pressure levels, while the children halted their weight gain. We believe this multidisciplinary, behavior-oriented, school-based program can be an effective cardiovascular risk intervention adaptable for a clinical office practice.  相似文献   
50.
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