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   18529篇
  免费   1939篇
  国内免费   31篇
耳鼻咽喉   161篇
儿科学   687篇
妇产科学   320篇
基础医学   2581篇
口腔科学   350篇
临床医学   1973篇
内科学   3509篇
皮肤病学   461篇
神经病学   1722篇
特种医学   703篇
外国民族医学   11篇
外科学   1989篇
综合类   334篇
一般理论   25篇
预防医学   2013篇
眼科学   735篇
药学   1498篇
中国医学   14篇
肿瘤学   1413篇
  2021年   257篇
  2020年   153篇
  2019年   316篇
  2018年   306篇
  2017年   212篇
  2016年   253篇
  2015年   320篇
  2014年   423篇
  2013年   608篇
  2012年   818篇
  2011年   880篇
  2010年   479篇
  2009年   443篇
  2008年   717篇
  2007年   729篇
  2006年   729篇
  2005年   737篇
  2004年   759篇
  2003年   673篇
  2002年   640篇
  2001年   635篇
  2000年   675篇
  1999年   530篇
  1998年   243篇
  1997年   224篇
  1996年   193篇
  1995年   196篇
  1994年   167篇
  1993年   169篇
  1992年   424篇
  1991年   424篇
  1990年   419篇
  1989年   421篇
  1988年   369篇
  1987年   420篇
  1986年   347篇
  1985年   367篇
  1984年   287篇
  1983年   268篇
  1982年   163篇
  1981年   161篇
  1980年   161篇
  1979年   279篇
  1978年   227篇
  1977年   161篇
  1976年   163篇
  1975年   165篇
  1974年   182篇
  1973年   172篇
  1972年   171篇
排序方式: 共有10000条查询结果,搜索用时 198 毫秒
951.
952.
Strategic self-presentation (motivational intervention [MI]) is a theoretical approach that is distinct from social cognitive theory (SCT). Specifically, strategic self-presentation involves increasing motivation by creating cognitive dissonance and inducing shifts in self-concept by generating positive coping strategies during a videotaped session. Fifty-three healthy African American adolescents were randomized to a SCT + MI, SCT-only, or an education-only group for increasing fruit and vegetable (F&V) intake and physical activity. The SCT + MI and SCT-only groups received a 12-week SCT program. Students in the SCT+ MI group also participated in a strategic self-presentation videotape session. Participantscompleted3-dayfoodrecords, completedmeasures of self-concept and self-efficacy, and wore an activity monitor for 4 days atpre-and posttreatment. Both the SCT+MI (2.6 ± 1.4vs. 5.7 ± 2.2, p<. 05) andthe SCT-only (2.5 ± 1.2 vs. 4.8 ± 2.4, p <. 05) groups showed greater increases in F&V intake from pre-to posttreatment as compared with the education-only group (2.3 ± 1.0, vs. 3.3 ± 2.1, p > .05). There were no significant time or group effects for any of the physical activity measures. Correlation analyses revealed that only the SCT + MI group showed that dietary self-concept (r = .58,r = .67,p<.05) and dietary self-efficacy (r = .65, r = .85, p < .05) were significantly correlated with posttreatment F&V intake and change in F&V intake, respectively. These findings suggest that the change in F&V intake in the SCT + MI group resulted from strategic self-presentation, which induced positive shifts in self-concept and self-efficacy. This project was supported by a National Kidney Foundation Virginia State Affiliate Grant to Dawn K. Wilson and by GCRC Grant M01RR00065 at Virginia Commonwealth University.  相似文献   
953.
This paper focuses on the lack of dialogue and policy consonance between those taking the lead in health systems change and those developing specific disease control strategies. In the first part, the origins and characteristics of this situation are explained using, as an example, TB control. Attention is then paid to the development of disease control friendly health systems. Four aspects of policy development are analysed paying particular attention to TB control: analysis of policy context, mechanisms for collaboration between policy actors; agreement on decision-making processes; development of common aims and objectives. Although the focus is on TB control, the principles illustrated carry some relevance for other disease control programmes.  相似文献   
954.
Nurse practitioners have evolved into a large and flexible workforce. Far too often, nurse practitioner and physician professional organizations do not work together but rather expend considerable effort jousting in policy arenas. Turf battles interfere with joint advocacy for needed health system change and delay development of interdisciplinary teams that could help patients. A combined, consistent effort is urgently needed for studying, training, and deploying a collaborative, integrated workforce aimed at improving the health care system of tomorrow. The country can ill afford doctors and nurses who ignore one another's capabilities and fail to maximize each other's contributions cost-effectively.  相似文献   
955.
BACKGROUND: Hip dislocation in children with cerebral palsy has a well-documented history and morbidity. OBJECTIVE: This paper presents a retrospective study of children with bilateral cerebral palsy who had various postural management and its effect on hip deformity. The most widely accepted theoretical model of hip subluxation/dislocation is that an imbalance in muscle length and strength around the hip leads to acetabular dysplasia and consequent hip subluxation. Maintenance of muscle length and strength and loadbearing is therefore a logical prevention. Research on normal infants' postures has provided biomechanical data to form the theoretical basis of 24 h postural management equipment. METHODS: The notes and X-rays of 59 children with bilateral cerebral palsy from East and West Sussex and Oxfordshire were examined and measured to determine whether a relationship existed between postural management and the level of hip subluxation/dislocation. X-rays were measured using Reimers' hip migration percentage. Postural management support was divided into three groups for analysis. Category 1: use of a 24-h postural management approach using Chailey Adjustable Postural Support (CAPS) systems in lying, sitting and standing; category 2: two items of CAPS (either lying/sitting or sitting/standing supports); category 3: use of the CAPS seat only and/or any other postural supports. Hip status was recorded for analysis as both hips safe (under 33% migrated), or one/both hips subluxed. RESULTS: Children using 'All CAPS' before hip subluxation maintained significantly more hip integrity than other groups (chi2 P < 0.05). CONCLUSIONS: Postural management interventions have an important role in the prevention of hip dysplasia.  相似文献   
956.
957.
958.
959.
Cancer therapies based on the inhibition of angiogenesis by endostatin have recently been developed. We demonstrate that a mutated form of human endostatin (P125A) can inhibit the angiogenic switch in the C3(1)/Tag mammary cancer model. P125A has a stronger growth-inhibitory effect on endothelial cell proliferation than wild-type endostatin. We characterize the angiogenic switch, which occurs during the transition from preinvasive lesions to invasive carcinoma in this model, and which is accompanied by a significant increase in total protein levels of vascular endothelial growth factor (VEGF) and an invasion of blood vessels. Expression of the VEGF(188) mRNA isoform, however, is suppressed in invasive carcinomas. The VEGF receptors fetal liver kinase-1 (Flk-1) and Fms-like tyrosine kinase-1 (Flt-1) become highly expressed in epithelial tumor and endothelial cells in the mammary carcinomas, suggesting a potential autocrine effect for VEGF on tumor cell growth. Angiopoietin-2 mRNA levels are also increased during tumor progression. CD-31 (platelet-endothelial cell adhesion molecule [PECAM]) staining revealed that blood vessels developed in tumors larger than 1 mm The administration of P125A human endostatin in C3(1)/Tag females resulted in a significant delay in tumor onset, decreased tumor multiplicity and tumor burden and prolonged survival of the animals. Endostatin treatment did not reduce the number of preinvasive lesions, proliferation rates or apoptotic index, compared with controls. However, mRNA levels of a variety of proangiogenic factors (VEGF, VEGF receptors Flk-1 and Flt-1, angiopoietin-2, Tie-1, cadherin-5 and PECAM) were significantly decreased in the endostatin-treated group compared with controls. These results demonstrate that P125A endostatin inhibits the angiogenic switch during mammary gland adenocarcinoma tumor progression in the C3(1)/Tag transgenic model.  相似文献   
960.
The effective and efficient delivery of cervical screening programs requires information for planning, management, delivery and evaluation. Specially designed systems are generally required to meet these needs. In many developing countries, lack of information systems constitutes an important barrier to development of comprehensive screening programs and the effective control of cervical cancer. Our report outlines a framework for creating such systems in developing countries and describes a conceptual model for a cervical screening information system. The proposed system is modular, recognizing that there will be considerable between-region heterogeneity in current status and priorities. The proposed system is centered on modules that would allow for the assembly and computerization of data on Pap tests, since these represent the main screening modality at the present time. Additional modules would process data and create and maintain a screening database (e.g., standardize, edit, link and update modules) and allow for the integration of other types of data, such as cervical histopathology results. An open systems development model is proposed, since it is most compatible with the goals of local stakeholder involvement and capacity-building.  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