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   989篇
  免费   78篇
  国内免费   6篇
儿科学   39篇
妇产科学   28篇
基础医学   236篇
口腔科学   11篇
临床医学   84篇
内科学   165篇
皮肤病学   36篇
神经病学   124篇
特种医学   9篇
外科学   78篇
综合类   18篇
预防医学   123篇
眼科学   18篇
药学   36篇
肿瘤学   68篇
  2023年   9篇
  2022年   11篇
  2021年   26篇
  2020年   11篇
  2019年   10篇
  2018年   15篇
  2017年   18篇
  2016年   23篇
  2015年   16篇
  2014年   18篇
  2013年   45篇
  2012年   48篇
  2011年   46篇
  2010年   30篇
  2009年   27篇
  2008年   55篇
  2007年   69篇
  2006年   66篇
  2005年   53篇
  2004年   41篇
  2003年   49篇
  2002年   43篇
  2001年   15篇
  2000年   12篇
  1999年   15篇
  1998年   11篇
  1997年   11篇
  1996年   9篇
  1995年   9篇
  1994年   13篇
  1993年   7篇
  1992年   10篇
  1991年   8篇
  1989年   14篇
  1987年   14篇
  1986年   11篇
  1985年   9篇
  1984年   9篇
  1983年   8篇
  1978年   6篇
  1977年   7篇
  1976年   6篇
  1971年   6篇
  1928年   7篇
  1927年   9篇
  1926年   6篇
  1925年   7篇
  1924年   5篇
  1923年   7篇
  1922年   6篇
排序方式: 共有1073条查询结果,搜索用时 31 毫秒
31.
Service-learning is increasingly becoming an avenue used in a variety of disciplines to provide students with real-life experience regarding aging and older adults. Developing and implementing meaningful service-learning experiences, however, requires consideration both of the discipline-specific content to be addressed, as well as the varied backgrounds (educational and personal) and levels (freshman to graduate) of the students who will be participating. Intergenerational service-learning is not a one-size-fits-all endeavor. Drawing on the experiences of intergenerational service-learning programs at three institutions (representing three disciplines-Gerontology, Nursing, and Occupational Therapy), this paper focuses on the discipline-specific challenges of building a quality intergenerational service-learning program, as well as the associated challenges of developing appropriate intergenerational service-learning experiences for a range of student levels with varied backgrounds.  相似文献   
32.
The initial experimental and clinical experience with the cardiovascular self-expandable Nitinol stent (vascular and coronary versions) is described. The stent is designed as a helical coil with two terminal balls that are used for restraining it on the delivery catheter. Upon release, the stent self-expands immediately. A temporary stent version continues with a long wire that can be removed by pulling it as a straight wire through a small profile catheter. The stent uncoils in its own groove upon removal, a relatively atraumatic procedure. The stents have been studied in dogs and in peripheral arteries in patients. The results show a transient nonocclusive proliferative response to the stent that is maximal at 3–6 mo. The removability of the permanent stent has been proven in dogs. The preliminary results in patients are encouraging and demonstrate its feasibility for permanent and potentially temporary arterial support. © 1994 Wiley-Liss,Inc..  相似文献   
33.
The relationship between gastrointestinal (GI) symptoms and uterine cramping pain at menses, controlling for affective states and prostaglandin synthesis inhibitor use, was examined. A total of 53 women completed a daily diary of symptoms, stool characteristics, and medication use for three consecutive menstrual cycles. There were significant across-women and within-woman relationships between stomach pain, nausea, and uterine cramping pain, but not between cramping pain and constipation, diarrhea, or stool characteristics. These results support the presence of a similar mechanism in the generation of distressing GI symptoms and uterine cramping pain at menses. © 1996 John Wiley & Sons, Inc.  相似文献   
34.

Objective

To develop a method for automated neonatal sleep state classification based on EEG that can be applied over a wide range of age.

Methods

We collected 231 EEG recordings from 67 infants between 24 and 45 weeks of postmenstrual age. Ten minute epochs of 8 channel polysomnography (N = 323) from active and quiet sleep were used as a training dataset. We extracted a set of 57 EEG features from the time, frequency, and spatial domains. A greedy algorithm was used to define a reduced feature set to be used in a support vector machine classifier.

Results

Performance tests showed that our algorithm was able to classify quiet and active sleep epochs with 85% accuracy, 83% sensitivity, and 87% specificity. The performance was not substantially lowered by reducing the epoch length or EEG channel number. The classifier output was used to construct a novel trend, the sleep state probability index, that improves the visualisation of brain state fluctuations.

Conclusions

A robust EEG-based sleep state classifier was developed. It performs consistently well across a large span of postmenstrual ages.

Significance

This method enables the visualisation of sleep state in preterm infants which can assist clinical management in the neonatal intensive care unit.  相似文献   
35.
The recently identified idiopathic short QT syndrome (SQTS) is associated with an increased risk of arrhythmia and sudden death. The use of implantable cardioverter defibrillators helps to protect SQTS patients from ventricular fibrillation; however, pharmacological treatments to normalise the QT interval are limited: thus far only quinidine has been found to be effective in a subset of patients, with the SQT1 variant. SQT1 is associated with an amino acid substitution (N588K) in the KCNH2-encoded HERG K(+) channel that reduces HERG current (I(HERG)) inactivation and sensitivity to drug block. We demonstrate here that the N588K-HERG mutation only slightly attenuates I(HERG) blockade by the Class Ia antiarrhythmic drug disopyramide (1.5-fold elevation of IC(50)), compared to quinidine (3.5-fold elevation of IC(50)) and the Class III antiarrhythmic drug E-4031 (11.5-fold elevation of IC(50)). Thus, of the drugs studied to date, disopyramide is the one least affected by the SQT1 HERG mutation. Disopyramide is associated with QT prolongation in normal use and our findings provide a rational basis for its evaluation as a treatment for SQT1.  相似文献   
36.

Background

There is increasing emphasis on involving intended beneficiaries and other stakeholders in the development of public health interventions to maximise acceptability and remove barriers to adoption, implementation, and maintenance before costly implementation. Yet the processes whereby key actors are engaged in intervention development are rarely reported, and frameworks for carrying out such work remain limited. We outline our approach to involving stakeholders in the optimisation of two school-based relationships and sex education programmes (Project Respect and Positive Choices) and reflect on the challenges of co-producing with teachers, students, and other partners.

Methods

Systematic optimisation of both interventions involved a review of existing literature on effective approaches; consultation with staff and students on intervention content and delivery; drafting of intervention materials; further consultation with schools; and then intervention refinement in preparation for a pilot. Seven focus groups took place in southeast and southwest England involving 75 students aged 13–15 years and 22 school staff. A group of young people trained to advise on public health research were consulted on two occasions and a wide range of sexual health and sex education practitioners and policy makers shared their views at a stakeholder event.

Findings

Consultation provided useful insights to inform intervention adaption in relation to who should deliver the programmes in schools; whether lessons should be taught in single sex classes; the format that guidance and lesson plans should take; the relevance and acceptability to students and teachers; and the need for the flexibility for materials to adapt to different school contexts. Genuine consultation and incorporation of school stakeholder views was challenging where stakeholder availability was limited and intervention development and implementation timelines were tight. Challenges also arose in relation to the weight to give divergent opinions among stakeholders and between stakeholders and researchers.

Interpretation

Carrying out structured stakeholder engagement activities can yield valuable insights that can improve the applicability of interventions to local contexts before they are formally trialled. To genuinely engage stakeholders in intervention development requires sufficient time to both consult and adapt. In such consultations, it is important to attend not just to the voices of those who are the loudest and most powerful.

Funding

National Institute for Health Research (NIHR).  相似文献   
37.
Protection of hair cells by HSP70 released by supporting cells is reported by May et al. in this issue of the JCI. Their findings suggest a new way to reduce ototoxicity from therapeutic medications and raise larger questions about the role and integration of heat shock proteins in non–cell-autonomous responses to stress. Increasing evidence suggests an important role for extracellular heat shock proteins in both the nervous system and the immune system. The work also suggests that defective chaperones could cause ear disease and supports the potential use of chaperone therapeutics.  相似文献   
38.
39.
Home observations were done on sibling interactions in 31 families with a child having Down's syndrome and a non-handicapped sibling. The siblings with Down's syndrome initiated less prosocial and agonistic behaviour, but imitated more frequently than their non-handicapped siblings. These effects were found regardless of birth order. There were no effects of gender. Higher levels of prosocial behaviours among large interval dyads and in dyads with a second-born Down's syndrome child were primarily due to the age of the non-handicapped sibling. Results were similar to those in previous "normative" studies of sibling interactions.  相似文献   
40.
Child and Parent Response to the 1993 World Trade Center Bombing   总被引:1,自引:0,他引:1  
This study evaluated children's symptoms 3 and 9 months after the 1993 bombing of the World Trade Center, and the relationship between parent and child reactions when only the children had been in the building. Nine children who had been trapped in an elevator, 13 who had been on the observation deck, and 27 controls completed the Posttraumatic Stress Reaction Index and a Fear Inventory. Parents completed these measures about the children and comparable measures about themselves. Exposed children reported posttraumatic stress disorder (PTSD) symptoms and disaster-related fears; their parents reported experiencing PTSD symptoms. Only parents rated children's symptoms as decreasing significantly over time. Association between child symptoms and parent symptoms increased over time. Children's initial distress predicted parents' distress 9 months postdisaster.  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