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   1124766篇
  免费   77338篇
  国内免费   1501篇
耳鼻咽喉   15493篇
儿科学   36003篇
妇产科学   29682篇
基础医学   160150篇
口腔科学   30687篇
临床医学   100681篇
内科学   213243篇
皮肤病学   25150篇
神经病学   85926篇
特种医学   45003篇
外国民族医学   201篇
外科学   171629篇
综合类   22460篇
现状与发展   1篇
一般理论   318篇
预防医学   79793篇
眼科学   25613篇
药学   89732篇
  8篇
中国医学   2855篇
肿瘤学   68977篇
  2021年   8578篇
  2019年   8721篇
  2018年   12467篇
  2017年   9769篇
  2016年   11025篇
  2015年   12349篇
  2014年   16848篇
  2013年   24505篇
  2012年   34019篇
  2011年   35838篇
  2010年   20883篇
  2009年   19523篇
  2008年   33056篇
  2007年   35382篇
  2006年   36000篇
  2005年   34225篇
  2004年   32638篇
  2003年   31380篇
  2002年   30195篇
  2001年   60833篇
  2000年   62248篇
  1999年   51706篇
  1998年   13053篇
  1997年   11487篇
  1996年   11466篇
  1995年   10821篇
  1994年   9770篇
  1993年   9246篇
  1992年   38324篇
  1991年   36770篇
  1990年   36222篇
  1989年   34754篇
  1988年   31296篇
  1987年   30360篇
  1986年   28593篇
  1985年   26843篇
  1984年   19530篇
  1983年   16422篇
  1982年   9078篇
  1979年   17291篇
  1978年   11640篇
  1977年   10428篇
  1976年   9037篇
  1975年   10243篇
  1974年   11859篇
  1973年   11462篇
  1972年   10936篇
  1971年   10242篇
  1970年   9424篇
  1969年   9098篇
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
101.
102.
ObjectiveIdentify factors associated with healthcare providers' frequency of depot medroxyprogesterone acetate (DMPA) provision to adolescents.Study designWe analyzed data from surveys mailed to a nationally representative sample of public-sector providers and office-based physicians (n=1984). We estimated adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of factors associated with frequent DMPA provision to adolescents in the past year.ResultsAlthough most providers (>95%) considered DMPA safe for adolescents, fewer reported frequent provision (89% of public-sector providers; 64% of office-based physicians). Among public-sector providers, factors associated with lower odds of frequent provision included working in settings without Title X funding (aOR 0.44, 95% CI 0.30–0.64), reporting primary care as their primary clinical focus versus reproductive or adolescent health (aOR 0.42, 95% CI 0.28–0.61), and providing fewer patients with family planning services. Among office-based physicians, factors associated with lower odds of frequent provision included specializing in obstetrics/gynecology (aOR 0.50, 95% CI 0.27–0.91) and family medicine (aOR 0.21, 95% CI 0.09–0.47) versus adolescent medicine, completing training ≥15 versus <5 years ago (aOR 0.27, 95% CI 0.09–0.83), and reporting that 0–24% of patients pay with Medicaid or other government healthcare assistance versus ≥50% (aOR 0.23, 95% CI 0.09–0.61). The reason most commonly reported by providers for infrequent DMPA provision was patient preference for another method.ConclusionsWhile most providers reported frequently providing DMPA to adolescents, training on evidence-based recommendations for contraception, focused on subgroups of providers with lower odds of frequent DMPA provision, may increase adolescents' access to contraception.ImplicationsAlthough >95% of providers considered depot medroxyprogesterone (DMPA) a safe contraceptive for adolescents, only 89% of public-sector providers and 64% of office-based physicians reported frequently providing DMPA to adolescents. Provider training on evidence-based recommendations for contraception counseling and provision may increase adolescents' access to DMPA and all methods of contraception.  相似文献   
103.
104.
105.
Unpredictable hypertrophic scarring (HS) occurs after approximately 35% of all surgical procedures and causes significant physical and psychological complaints. Parallel to the need to understanding the mechanisms underlying HS formation, a prognostic tool is needed. The objective was to determine whether (systemic) immunological differences exist between patients who develop HS and those who develop normotrophic scars (NS) and to assess whether those differences can be used to identify patients prone to developing HS. A prospective cohort study with NS and HS groups in which (a) cytokine release by peripheral blood mononuclear cells (PBMC) and (b) the irritation threshold (IT) after an irritant (sodium lauryl sulphate) patch test was evaluated. Univariate regression analysis of PBMC cytokine secretion showed that low MCP‐1, IL‐8, IL‐18 and IL‐23 levels have a strong correlation with HS (P < .010‐0.004; AUC = 0.790‐0.883). Notably, combinations of two or three cytokines (TNF‐a, MCP‐1 and IL‐23; AUC: 0.942, Nagelkerke R2: 0.727) showed an improved AUC indicating a better correlation with HS than single cytokine analysis. These combination models produce good prognostic results over a broad probability range (sensitivity: 93.8%, specificity 86.7%, accuracy 90,25% between probability 0.3 and 0.7). Furthermore, the HS group had a lower IT than the NS group and an accuracy of 68%. In conclusion, very fundamental immunological differences exist between individuals who develop HS and those who do not, whereas the cytokine assay forms the basis of a predictive prognostic test for HS formation, the less invasive, easily performed irritant skin patch test is more accessible for daily practice.  相似文献   
106.
This paper revisits a 2003 publication in Nursing Philosophy: The need for accurate perception and informed judgement in determining the appropriate use of the nursing resource: hearing the patient's voice. The author suggests that the basic ideas and focus of this 16‐year‐old paper are still topical and relevant in considerations of nursing care. However, it is also suggested that greater attention to the importance of the nurse–patient relationship in considerations of resource allocation, and potential rationing of nursing care, would have strengthened the original paper.  相似文献   
107.

Introduction/Hypothesis

Recruitment of participants into phase 1 vaccine clinical trials can be challenging since these vaccines have not been used in humans and there is no perceived benefit to the participant. Occasionally, as was the case with a phase 1 clinical trial of an Ebola vaccine in Halifax, Canada, during the 2014–2016 West African Ebola virus outbreak, recruitment is less difficult. In this study, we explored the motivations of participants in two phase 1 vaccine trials that were concurrently enrolling at the same centre and compared the motivations of participants in a high-profile phase 1 Ebola vaccine trial to those in a less high-profile phase 1 adjuvanted seasonal influenza vaccine study.

Methods

An online survey which included participants’ prior experience with clinical trials, motivations to participate (including financial incentives), and demographic information was developed to examine the motivations of healthy participants in two phase 1 clinical vaccine trials conducted at the Canadian Center for Vaccinology in Halifax, Nova Scotia. Participants were invited via email to complete the online survey. Readability and clarity were assessed through pilot testing.

Results

A total of 49 (55.7%) of 88 participants of the two studies completed the survey (22 [55%] of 40 participants from the Ebola vaccine study and 27 [56.3%] of 48 from the adjuvanted influenza vaccine study). Motivations that were most frequently ranked among participants' top three in both trials were (1) wanting to contribute to the health of others, (2) wanting to participate in something important, (3) wanting to contribute to the advancement of science, and (4) wanting to receive an incentive such as money or a tablet.

Conclusions/Recommendations

Although media attention and financial compensation were more often cited by Ebola vaccine trial participants as a reason to participate, both altruistic and self-interested factors were important motivations for participants in their decision to participate in a phase 1 vaccine clinical trial.  相似文献   
108.
109.
110.
Bulletin of Experimental Biology and Medicine - Fast neutron therapy, which previously has demonstrated effective results, but along with a large number of complications, can again be considered a...  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