全文获取类型
收费全文 | 4712篇 |
免费 | 380篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 209篇 |
妇产科学 | 177篇 |
基础医学 | 671篇 |
口腔科学 | 136篇 |
临床医学 | 417篇 |
内科学 | 781篇 |
皮肤病学 | 65篇 |
神经病学 | 331篇 |
特种医学 | 365篇 |
外科学 | 604篇 |
综合类 | 58篇 |
一般理论 | 6篇 |
预防医学 | 388篇 |
眼科学 | 252篇 |
药学 | 356篇 |
1篇 | |
中国医学 | 5篇 |
肿瘤学 | 267篇 |
出版年
2022年 | 35篇 |
2021年 | 54篇 |
2019年 | 58篇 |
2018年 | 62篇 |
2017年 | 52篇 |
2016年 | 61篇 |
2015年 | 85篇 |
2014年 | 111篇 |
2013年 | 158篇 |
2012年 | 181篇 |
2011年 | 197篇 |
2010年 | 117篇 |
2009年 | 118篇 |
2008年 | 177篇 |
2007年 | 224篇 |
2006年 | 179篇 |
2005年 | 184篇 |
2004年 | 139篇 |
2003年 | 149篇 |
2002年 | 126篇 |
2001年 | 134篇 |
2000年 | 152篇 |
1999年 | 104篇 |
1998年 | 89篇 |
1997年 | 91篇 |
1996年 | 92篇 |
1995年 | 82篇 |
1994年 | 71篇 |
1993年 | 59篇 |
1992年 | 85篇 |
1991年 | 97篇 |
1990年 | 110篇 |
1989年 | 105篇 |
1988年 | 107篇 |
1987年 | 120篇 |
1986年 | 84篇 |
1985年 | 121篇 |
1984年 | 81篇 |
1983年 | 74篇 |
1982年 | 49篇 |
1981年 | 52篇 |
1980年 | 42篇 |
1979年 | 54篇 |
1978年 | 54篇 |
1977年 | 58篇 |
1975年 | 40篇 |
1973年 | 45篇 |
1972年 | 41篇 |
1967年 | 32篇 |
1966年 | 38篇 |
排序方式: 共有5147条查询结果,搜索用时 33 毫秒
41.
42.
The ligands for several activating natural killer (NK) cell receptors have not been identified to date. Soluble receptor fusion proteins can be used to stain target cells for the presence of these unidentified ligands. Here, we describe the generation and use of soluble type I NK cell receptor isoleucine-zipper (ILZ) fusion proteins of the immunoglobulin (Ig) superfamily. ILZ-fusion proteins are easy to produce and purify. They form trimeric complexes in solution and display a higher binding avidity than classical immunoglobulin-fusion proteins. ILZ-fusion proteins do not interact with Fc-receptors and can therefore be used to block receptor-ligand interactions in cellular assays. This makes ILZ-fusion proteins a valuable tool to study receptor-ligand interactions in NK cells and other cellular systems. 相似文献
43.
44.
45.
Advances in intraocular surgery have decreased the incidence of corneal complications that result in corneal failure requiring transplantation. Interest continues in further refining surgery to minimize endothelial cell damage. New irrigating solutions, viscoelastic substances, and even new techniques have been introduced. Debate continues over certain issues, such as intraocular lens choice in the absence of capsular support. Improved design has prompted many early critics to regain confidence in the anterior chamber lens. Literature of recent years also reflects a shift in focus toward hastening recovery time and maximizing uncorrected visual acuity through the advantageous control of corneal astigmatism. Several reports this year may herald the next wave of interest, that surrounding intraocular surgery after refractive corneal surgery. 相似文献
46.
47.
A curriculum guide entitled "Heart Health Curriculum Guide" was developed with and by teachers in Peabody Public Schools under a Massachusetts Public Health grant to the American Heart Association. The 67-page manual describes the format of the 12-hour teacher workshop, background physiology of heart/circulatory system, hypertension risk factors, a set of 20 lessons, and evaluating procedures. (Copies may be obtained for $3.00 by writing the corresponding author.) As a result of teaching this unit, sixth grade students in each school ran a Blood Pressure Screening Clinic for their parents and school staff. 相似文献
48.
Annette J. Stark Ph.D. Gloria M. Gutman Ph.D. Kent Brothers Ph.D. 《Journal of community health》1982,8(2):102-109
This paper addresses the question of the degree of agreement between experienced assessors making level-of-care placement decisions for the same client, given a comparable opportunity to obtain and record client information in a community-based Long-Term Care program.A systematic sample of 246 cases was selected, consisting of 47 preadmission assessments and 199 reviews. The resulting data were subjected to analysis using the statistic Kappa and the degree of agreement categories suggested by Fleiss.1 It was found that at the level-of-care extremes— Extended Care and Personal Care—the agreement between two nurse assessors for reviews could be considered excellent. In the Intermediate Care range, however, the reliability of the level-of-care decision can only be considered fair. Agreement for initial assessments was less, withK=0.469 indicating, overall, only fair agreement. While there was most often only a one-care-level difference between assessors, the program assessor tended to recommend a higher level than the study or check assessor. This has implications for funding agencies and/or facility planners who must assess the likely care requirements of an increasing number of disabled elderly. From a program management perspective, the preceding analyses allow an objective judgement of the extent of the placement decision problem, if any, and further provide a definition of areas most in need of revision. The value of collaboration between practitioner and researcher is evident in these analyses.Dr. Stark is Director, Division of Health Services Research and Development and Assistant Professor, Department of Health Care and Epidemiology, The University of British Columbia. Dr. Gutman is Director, Gerontology Centre and Associate Professor, Faculty of Interdisciplinary Studies, Simon Fraser University. Dr. Brothers is Research Associate, Division of Health Systems, The University of British Columbia. Address enquiries to Dr. A. Stark, Director, Division of Health Services Research and Development, Office of the Coordinator of Health Sciences, The John F. McCreary Health Sciences Centre, 2194 Health Sciences Mall, The University of British Columbia, Vancouver, B.C., V6T 1Z6.The research described in this paper, as well as the larger study of which it is a part, is supported by a grant from the B.C. Health Care Research Foundation. In addition, the cooperation and support of the Ministry of Health, Province of British Columbia is gratefully acknowledged. 相似文献
49.
Health care consumers use a plethora of services which are accessible on an ambulatory basis. These include the services of pharmacists, optometrists, nurses, dentists, audiologists, orthotics, and so forth. Since many of these services are provided in physically and financially separate facilities and often are not located in close proximity to one another, consumers may spend a large amount of time traveling between locations. Economic inefficiencies due to the size and dispersion of separate and independent facilities may produce an increase in the cost of ambulatory health care services. Thus, the concept of a health care center, an ambulatory health care analog to the multispecialty shopping center, is proposed as a potential alternative and improvement in the delivery of these services. Space, location, personnel, and initial capital requirements for a model health care center are projected based on existing data for the establishment of each separate auxiliary health care facility. Projections are made to determine the appropriate and necessary site for the health care center's trade area. Potential revenues are calculated by examining some pharmacy operations which are beginning to pioneer these areas and utilizing revenue figures for the various individual services. The results indicate that the pharmacy, as a frequently visited health care facility, may be an excellent choice around which to develop the health care center concept in metropolitan areas. 相似文献
50.
Previous studies employed a second-order schedule paradigm maintained by cocaine reinforcement to show that BP897, a dopamine D(3) partial agonist, selectively modulated drug-seeking behavior. We investigated its effect on drug-seeking behavior induced by presentation of stimuli associated with and predictive of cocaine availability after a period of extinction and in the absence of any further cocaine. Male rats were trained to associate discriminative stimuli (S(D)) with the availability of intravenous (i.v.) 0.25 mg/0.1 ml/infusion cocaine (S(D+)) or no-reward (S(D-)) saline solution. Each infusion of cocaine or saline was followed by a response-cue signaling 20-s time-out (TO). After meeting the self-administration training criterion rats were placed on extinction conditions during which i.v. solutions and S(D)s were withheld. Every other 3 days on which rats met the extinction criterion, reinstatement tests were conducted, presenting the S(D+) or S(D-) noncontingently together with a contingent presentation of cocaine- or saline-cues signaling 20-s TO. Regardless of the order of presentation or the nature of the stimuli (auditory or visual), cocaine-associated but not saline-associated stimuli reinstated responding on the previously active lever. Presentation of cocaine-associated stimuli induced lasting drug-seeking behavior for at least eight test sessions. BP897 (1.0 mg/kg i.p.) significantly attenuated this behavior. Since it has been reported that BP897 can interact with a panel of different receptors with high affinity, we evaluated the effects of 7-OH-DPAT, an agonist to D(3) receptors, raclopride, a preferential antagonist to D(2) receptors, and WAY 100,635, an antagonist at 5-HT(1A) receptors, on drug-seeking behavior. 7-OH-DPAT (0.1-3.0 mg/kg i.p.) had biphasic effects on reinstatement induced by the cocaine-associated cues, low dosages reducing and high dosages increasing the impact of cocaine-associated stimuli on rats' behavior. Raclopride (0.1, 0.3 mg/kg s.c.) completely prevented drug-seeking behavior induced by the reintroduction of cocaine-associated stimuli. WAY 100,635 (0.1-1.0 mg/kg s.c.) had no effect on this behavior. These results, while confirming that the partial agonist at the D(3) receptors, BP897, might be a useful medication, also suggest a role of D(2) receptors in cue-induced cocaine-seeking behavior. 相似文献