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   8557篇
  免费   898篇
  国内免费   14篇
耳鼻咽喉   80篇
儿科学   242篇
妇产科学   247篇
基础医学   1359篇
口腔科学   180篇
临床医学   965篇
内科学   1611篇
皮肤病学   118篇
神经病学   826篇
特种医学   337篇
外科学   1181篇
综合类   208篇
一般理论   8篇
预防医学   884篇
眼科学   161篇
药学   562篇
中国医学   17篇
肿瘤学   483篇
  2022年   52篇
  2021年   115篇
  2020年   61篇
  2019年   111篇
  2018年   147篇
  2017年   106篇
  2016年   103篇
  2015年   133篇
  2014年   208篇
  2013年   286篇
  2012年   381篇
  2011年   401篇
  2010年   232篇
  2009年   206篇
  2008年   370篇
  2007年   386篇
  2006年   430篇
  2005年   390篇
  2004年   371篇
  2003年   379篇
  2002年   405篇
  2001年   314篇
  2000年   300篇
  1999年   258篇
  1998年   124篇
  1997年   85篇
  1996年   91篇
  1995年   83篇
  1994年   95篇
  1993年   89篇
  1992年   190篇
  1991年   197篇
  1990年   184篇
  1989年   181篇
  1988年   161篇
  1987年   177篇
  1986年   157篇
  1985年   169篇
  1984年   130篇
  1983年   93篇
  1982年   60篇
  1981年   54篇
  1980年   57篇
  1979年   76篇
  1978年   60篇
  1977年   62篇
  1975年   66篇
  1974年   62篇
  1973年   65篇
  1972年   57篇
排序方式: 共有9469条查询结果,搜索用时 15 毫秒
1.
Patient navigation is a strategy for overcoming barriers to reduce disparities and to improve access and outcomes. The aim of this umbrella review was to identify, critically appraise, synthesize, and present the best available evidence to inform policy and planning regarding patient navigation across the cancer continuum. Systematic reviews examining navigation in cancer care were identified in the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, Cumulative Index of Nursing and Allied Health (CINAHL), Epistemonikos, and Prospective Register of Systematic Reviews (PROSPERO) databases and in the gray literature from January 1, 2012, to April 19, 2022. Data were screened, extracted, and appraised independently by two authors. The JBI Critical Appraisal Checklist for Systematic Review and Research Syntheses was used for quality appraisal. Emerging literature up to May 25, 2022, was also explored to capture primary research published beyond the coverage of included systematic reviews. Of the 2062 unique records identified, 61 systematic reviews were included. Fifty-four reviews were quantitative or mixed-methods reviews, reporting on the effectiveness of cancer patient navigation, including 12 reviews reporting costs or cost-effectiveness outcomes. Seven qualitative reviews explored navigation needs, barriers, and experiences. In addition, 53 primary studies published since 2021 were included. Patient navigation is effective in improving participation in cancer screening and reducing the time from screening to diagnosis and from diagnosis to treatment initiation. Emerging evidence suggests that patient navigation improves quality of life and patient satisfaction with care in the survivorship phase and reduces hospital readmission in the active treatment and survivorship care phases. Palliative care data were extremely limited. Economic evaluations from the United States suggest the potential cost-effectiveness of navigation in screening programs.  相似文献   
2.
3.
4.
A new strategy to yield information from the maximum number of voxels, each at the optimum signal-to-noise ratio (SNR) per unit time, in MR spectroscopic imaging (MRSI) is introduced. In the past, maximum acquisition duty-cycle was obtained by multiplexing in time several single slices each repetition time (TR), while optimal SNR was achieved by encoding the entire volume of interest (VOI) each TR. We show that optimal SNR and acquisition efficiency can both be achieved simultaneously by multiplexing in space and time several slabs of several slices, each. Since coverage of common VOIs in 3D proton MRSI in the human brain typically requires eight or more slices, at 3 T or higher magnetic fields, two or more slabs can fit into the optimum TR (approximately 1.6 s). Since typically four or less slices would then fit into each slab, Hadamard encoding is favored in that direction for slice profile reasons. It is demonstrated that per fixed examination length, the new method gives, at 3 T, twice as many voxels, each of the same SNR and size, compared with current 3D chemical shift imaging techniques. It is shown that this gain will increase for more extensive spatial coverage or higher fields.  相似文献   
5.
6.
A crossover double-blind controlled trial was performed on 36 patients with rheumatoid arthritis to assess the necessity for serum salicylate monitoring in determining optimal dosage. There was no clinically or statistically significant increase in the clinical improvement of patients associated with serum monitoring but potentially toxic serum levels occurred without tinnitus when serum monitoring was not used.  相似文献   
7.
8.
The well-publicised dangers of contracting infection from blood-borne viruses make an awareness of comprehensive protective measures for self and others an imperative for nurses. Sarah Hart reviews the precautions nurses should take when dealing with contaminated blood and other body fluids, and lays emphasis on the need for all nurses, regardless of the particular area in which they work, to adopt and promote safe practices.  相似文献   
9.
Free flaps have been used for over 30 years. During this period, improved anatomical understanding has increased donor options and available pedicle lengths, permitting safer, single-stage reconstructions with simpler anastomoses. Refinements, such as perforator flaps in particular, have greatly improved donor morbidity, recipient site cosmesis, and the ability to replace 'like with like' while retaining options for innervation. This case highlights the evolution from one of Europe's first free tissue transfers, effectively a perforator flap, through the advent of free muscle flaps to the current generation of contourable perforator flaps. Free flap transfer has become increasingly sophisticated, safer, and more predictable, yet the potential quality of reconstructive outcome has changed little.  相似文献   
10.
We previously showed that a low frequency (1 Hz) train of perforant path stimulation evokes burst discharges in the dentate gyrus of hippocampal slices obtained from patients surgically treated for intractable temporal lobe epilepsy. We report here that multiple population spikes that characterize the burst discharge are blocked reversibly by the specific NMDA receptor antagonist, D-(-)-2-amino-5-phosphonovaleric acid (D-APV). The epileptiform discharge evoked in human dentate gyrus by stimulation trains of 1 Hz could be reproduced in the rat dentate gyrus in vitro by the same stimulation protocol but required the presence of low concentrations (0.2-0.6 mM) of extracellular magnesium. We suggest that low frequency orthodromic stimulation of dentate granule cells through the perforant path progressively evokes an increase in the activation of NMDA receptors resulting in burst discharges in tissue from epileptic patients.  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