全文获取类型
收费全文 | 80445篇 |
免费 | 5970篇 |
国内免费 | 585篇 |
专业分类
耳鼻咽喉 | 1057篇 |
儿科学 | 2077篇 |
妇产科学 | 1306篇 |
基础医学 | 10598篇 |
口腔科学 | 1273篇 |
临床医学 | 8407篇 |
内科学 | 16245篇 |
皮肤病学 | 1361篇 |
神经病学 | 6695篇 |
特种医学 | 3088篇 |
外国民族医学 | 18篇 |
外科学 | 12227篇 |
综合类 | 2038篇 |
现状与发展 | 2篇 |
一般理论 | 34篇 |
预防医学 | 6369篇 |
眼科学 | 1668篇 |
药学 | 6072篇 |
7篇 | |
中国医学 | 697篇 |
肿瘤学 | 5761篇 |
出版年
2023年 | 578篇 |
2022年 | 1110篇 |
2021年 | 2291篇 |
2020年 | 1307篇 |
2019年 | 2026篇 |
2018年 | 2440篇 |
2017年 | 1764篇 |
2016年 | 1769篇 |
2015年 | 2156篇 |
2014年 | 2999篇 |
2013年 | 3846篇 |
2012年 | 5750篇 |
2011年 | 6011篇 |
2010年 | 3443篇 |
2009年 | 2887篇 |
2008年 | 4694篇 |
2007年 | 5054篇 |
2006年 | 4804篇 |
2005年 | 4568篇 |
2004年 | 4022篇 |
2003年 | 3954篇 |
2002年 | 3585篇 |
2001年 | 1452篇 |
2000年 | 1319篇 |
1999年 | 1316篇 |
1998年 | 827篇 |
1997年 | 630篇 |
1996年 | 550篇 |
1995年 | 500篇 |
1994年 | 448篇 |
1993年 | 376篇 |
1992年 | 671篇 |
1991年 | 635篇 |
1990年 | 611篇 |
1989年 | 578篇 |
1988年 | 587篇 |
1987年 | 503篇 |
1986年 | 474篇 |
1985年 | 494篇 |
1984年 | 401篇 |
1983年 | 315篇 |
1982年 | 281篇 |
1981年 | 241篇 |
1980年 | 243篇 |
1979年 | 285篇 |
1978年 | 198篇 |
1977年 | 184篇 |
1976年 | 164篇 |
1974年 | 170篇 |
1972年 | 154篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Non-invasive tear break-up time (NITBUT) has been proposed as a measure of tear film integrity which is superior to the more commonly used tear break-up time (TBUT), since it does not alter the volume or the physicochemical properties of the tear layer by the addition of fluorescein. We measured NITBUT by measuring the time taken for distortions or discontinuities to appear in the reflected image of a grid pattern which covered about 80 per cent of the corneal surface. NITBUT measures were made 100 times on seven Hong Kong Chinese subjects with up to 20 consecutive measures being made on a single day. We also measured NITBUT on one occasion on an unselected population of 52 Hong Kong Chinese subjects. NITBUT shows a skewed distribution in all subjects, with many shorter values and some extremely long values. There are statistically significant variations in NITBUT from day to day, and from subject to subject. The group of 52 subjects also had a skewed NITBUT distribution with many short values and some very long values. The arithmetic mean does not adequately represent NITBUT data, either for individual subjects or for this group of subjects. As many as five to eight measures may be necessary to gain a stable estimate of the NITBUT and stability of the measure is improved if extreme values are omitted. We recommend the use of nonparametric statistics to compare NITBUT values from day to day in or between subjects. 相似文献
62.
ATP synthesis from PCr through creatine kinase reaction was measured in vivo in rat leg muscle using 31P NMR magnetization transfer and progressive saturation. Both techniques determined a spin-lattice relaxation time for PCr of 3 s at rest and an identical forward rate constant of 0.22-0.26 s-1. In stimulated muscles, magnetization transfer showed that flux was not changed with a steady-state PCr of 54% of initial level. During stimulation inducing a PCr decrease to 38% of initial value, flux was significantly lowered by 30%. These findings could result from an accumulation of ions and water increases or from compartmentation of ATP and PCr in different pools either in the muscle cell or in the different muscle fibers. In addition, these results could reinforce the hypothesis against a crucial role for creatine kinase shuttle in the ATP supply in skeletal muscle. 相似文献
63.
There is growing interest in the phenomenon of long-term depression (LTD) of synaptic efficacy that, together with long-term potentiation (LTP), is a putative information storage mechanism in mammalian brain. In neural network models, multiple learning rules have been used for LTD induction. Similarly, in neurophysiological studies of hippocampal synaptic plasticity, a variety of activity patterns have been effective at inducing LTD, although experimental paradigms are still being optimized. In this review the authors summarize the major experimental paradigms and compare what is known about the mechanisms of LTD induction. Although all paradigms appear to initiate a cascade of events leading to an elevated level of Ca2+ postsynaptically, the extent to which these paradigms involve common expression mechanisms has not yet been tested. The authors discuss several critical experiments that would address this latter issue. Numerous questions about the properties and mechanisms of LTD(s) in the hippocampus remain to be answered, but it is clear that LTD has finally arrived, and will soon be attracting attention equal to its flip side, LTP. © 1994 Wiley-Liss, Inc. 相似文献
64.
G Brian J Dalzell S Nangala F Hollows 《Australian and New Zealand journal of ophthalmology》1990,18(1):99-102
The inequitable distribution of medical services in Australia means that many rural dwellers do not have easy access to ophthalmic care. In regions with no medical personnel, appropriately trained rural health workers may provide ophthalmic assessment, primary treatment, and, in some circumstances, definitive care. In areas with overburdened services, these rural health workers may augment facilities already established. In an attempt to improve the accessibility and quality of ophthalmic services available to presently disadvantaged rural inhabitants, the aims, curriculum, and structure of a 'Basic Ophthalmic Assessment and Care Workshop', for the transfer of knowledge and skills to such rural health workers, is presented. 相似文献
65.
66.
Edwin D. Boudreaux PhD Brian L. Cruz MD Brigitte M. Baumann MD 《Academic emergency medicine》2006,13(7):795-802
Objectives: The authors reviewed the evidence on performance improvement methods for increasing emergency department (ED) patient satisfaction to provide evidence-based suggestions for clinical practice.
Methods: Data sources consisted of searches through MEDLINE, CINAHL, PSYCHINFO, Cochrane Library, and Emergency Medicine Abstracts and a manual search of references. Articles were included if they reported a performance improvement intervention targeting patient satisfaction in the ED setting. Articles on studies not conducted in the United States or that failed to provide enough details to allow critical evaluation of the study were excluded. Two authors used structured evaluation criteria to independently review each retained study.
Results: Nineteen articles met all selection criteria. Three studies found varying levels of support for multicomponent interventions, predominantly focused on implementation of clinical practice guidelines for specific presenting complaints and process redesign. Sixteen studies evaluated single-component interventions, with the following having at least one supportive study: using alternating patient assignment to provider teams rather than "zone"-based assignment, enhancing provider communication and customer service skills, incorporating information delivery interventions (e.g., pamphlets, video) that target patient expectations, using preformatted charts, and establishing ED-based observation units for specific conditions such as asthma and chest pain.
Conclusions: There is modest evidence supporting a range of performance improvement interventions for improving ED patient satisfaction. Further work is needed before specific, evidence-based recommendations can be made regarding which process changes are most effective. Recommendations are made for improving the quality of performance improvement efforts in the ED setting. 相似文献
Methods: Data sources consisted of searches through MEDLINE, CINAHL, PSYCHINFO, Cochrane Library, and Emergency Medicine Abstracts and a manual search of references. Articles were included if they reported a performance improvement intervention targeting patient satisfaction in the ED setting. Articles on studies not conducted in the United States or that failed to provide enough details to allow critical evaluation of the study were excluded. Two authors used structured evaluation criteria to independently review each retained study.
Results: Nineteen articles met all selection criteria. Three studies found varying levels of support for multicomponent interventions, predominantly focused on implementation of clinical practice guidelines for specific presenting complaints and process redesign. Sixteen studies evaluated single-component interventions, with the following having at least one supportive study: using alternating patient assignment to provider teams rather than "zone"-based assignment, enhancing provider communication and customer service skills, incorporating information delivery interventions (e.g., pamphlets, video) that target patient expectations, using preformatted charts, and establishing ED-based observation units for specific conditions such as asthma and chest pain.
Conclusions: There is modest evidence supporting a range of performance improvement interventions for improving ED patient satisfaction. Further work is needed before specific, evidence-based recommendations can be made regarding which process changes are most effective. Recommendations are made for improving the quality of performance improvement efforts in the ED setting. 相似文献
67.
68.
Tod B Sloan Celia I Kaye William R Allen Brian E Magness Steven A Wartman 《Academic medicine》2005,80(11):994-1004
Changes in the education, research, and health care environments have had a major impact on the way in which medical schools fulfill their missions, and mission-based management approaches have been suggested to link the financial information of mission costs and revenues with measures of mission activity and productivity. The authors describe a simpler system, termed Mission-Aligned Planning (MAP), and its development and implementation, during fiscal years 2002 and 2003, at the School of Medicine at the University of Texas Health Science Center at San Antonio, Texas. The MAP system merges financial measures and activity measures to allow a broad understanding of the mission activities, to facilitate strategic planning at the school and departmental levels. During the two fiscal years mentioned above, faculty of the school of medicine reported their annual hours spent in the four missions of teaching, research, clinical care, and administration and service in a survey designed by the faculty. A financial profit or loss in each mission was determined for each department by allocation of all departmental expenses and revenues to each mission. Faculty expenses (and related expenses) were allocated to the missions based on the percentage of faculty effort in each mission. This information was correlated with objective measures of mission activities. The assessment of activity allowed a better understanding of the real costs of mission activities by linking salary costs, assumed to be related to faculty time, to the missions. This was a basis for strategic planning and for allocation of institutional resources. 相似文献
69.
Couples in remarriages with stepchildren are a significant portion of the marriage population and have unique educational needs regarding aspects of couple functioning within the context of stepfamily development. From a review of the literature, we examine current curricula focused on these couples. Information is offered on implementation issues regarding recruitment, delivery context, facilitator and participant characteristics, and evaluation. 相似文献
70.