全文获取类型
收费全文 | 20762篇 |
免费 | 1354篇 |
国内免费 | 287篇 |
专业分类
耳鼻咽喉 | 41篇 |
儿科学 | 513篇 |
妇产科学 | 203篇 |
基础医学 | 3638篇 |
口腔科学 | 368篇 |
临床医学 | 2072篇 |
内科学 | 1649篇 |
皮肤病学 | 149篇 |
神经病学 | 3950篇 |
特种医学 | 183篇 |
外国民族医学 | 1篇 |
外科学 | 515篇 |
综合类 | 1808篇 |
一般理论 | 1篇 |
预防医学 | 4419篇 |
眼科学 | 38篇 |
药学 | 2310篇 |
10篇 | |
中国医学 | 224篇 |
肿瘤学 | 311篇 |
出版年
2024年 | 76篇 |
2023年 | 320篇 |
2022年 | 700篇 |
2021年 | 971篇 |
2020年 | 740篇 |
2019年 | 610篇 |
2018年 | 563篇 |
2017年 | 648篇 |
2016年 | 696篇 |
2015年 | 668篇 |
2014年 | 1179篇 |
2013年 | 1602篇 |
2012年 | 1012篇 |
2011年 | 1168篇 |
2010年 | 844篇 |
2009年 | 884篇 |
2008年 | 921篇 |
2007年 | 880篇 |
2006年 | 827篇 |
2005年 | 662篇 |
2004年 | 542篇 |
2003年 | 518篇 |
2002年 | 455篇 |
2001年 | 349篇 |
2000年 | 273篇 |
1999年 | 260篇 |
1998年 | 213篇 |
1997年 | 201篇 |
1996年 | 170篇 |
1995年 | 162篇 |
1994年 | 147篇 |
1993年 | 127篇 |
1992年 | 138篇 |
1991年 | 131篇 |
1990年 | 114篇 |
1989年 | 119篇 |
1988年 | 121篇 |
1987年 | 99篇 |
1986年 | 148篇 |
1985年 | 247篇 |
1984年 | 242篇 |
1983年 | 174篇 |
1982年 | 213篇 |
1981年 | 200篇 |
1980年 | 195篇 |
1979年 | 181篇 |
1978年 | 127篇 |
1977年 | 139篇 |
1976年 | 130篇 |
1975年 | 92篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Katherine A. Vittes Ph.D. Susan B. Sorenson Ph.D. 《The Journal of adolescent health》2006,39(6):929-932
In a survey of 5657 community-residing adolescents, those who said they could get a handgun in two days reported similar and those who said they could not get a handgun reported fewer risk behaviors and less violence perpetration and victimization than adolescents who have their own handgun. Adolescents who said they could get a handgun reported more exposure to and experience with firearms than those who said they could not get a handgun. Risk reduction efforts regarding adolescents should be expanded to include adolescents who say they can get a handgun. 相似文献
32.
Kelvin L Chou Maria L Moro-De-Casillas Melissa M Amick Leora L Borek Joseph H Friedman 《Movement disorders》2007,22(3):411-414
We examined the relationship between testosterone levels, violent dreams, and REM sleep behavior disorder (RBD) in 31 men with Parkinson's disease (PD): 12 with clinical RBD and 19 without. All PD patients with clinical RBD experienced violent dreams, but none of the 19 non-RBD patients reported violent dreams. While dream content appears to be more aggressive in PD patients with clinical RBD, the presence of violent dreams or clinical RBD is not associated with testosterone levels in men with PD. 相似文献
33.
John R. Glowa 《Drug development research》1990,20(4):411-428
Volatile organic solvents exhibit a range of behavioral effects from the insidiously toxic to the beneficial. Solvents impair performance in a concentration-dependent manner that depends on the unique physicochemical properties of each solvent. The toxic effects of solvents range greatly but, at sufficient concentrations, or after prolonged exposure, neurotoxic effects are often seen. Many solvents are both self-administered and exhibit noxious properties. Solvents may produce some of their primary behavioral effects by altering γ-amino-butyric acid (GABA) function. Further studies related to mechanism may lead to a better understanding of means to protect individuals from the effects of solvent exposure, as well as further our knowledge of solvent abuse. Solvents activate the stress axis and, as such, their neuroendocrine effects deserve further characterization, because chronic exposure may result in altered neuronal activity similar to that associated with chronic stress. Methods have been developed to assess for risk of the effects of exposure to solvents, detailing the lowest levels of solvent expected to produce behavioral impairment. Results from these procedures should be applied to the different end points described. 相似文献
34.
David W Lawrence 《Injury prevention》2007,13(4):232-236
OBJECTIVE: To assess the capacity of textword queries to provide a comprehensive listing of articles on injury prevention and safety promotion (IPSP) concepts in a literature database. METHODS: All terms used to search SafetyLit (a database of scholarly literature selected for its relevance to the IPSP field) during the years 2000-2005 were listed and then examined to identify terms that are synonyms for the same concept. Terms were grouped by concept, the number of queries that used terms within each concept category were summed, and the concepts were then ordered by the total number of searches for each concept category. For each textword, the proportion of all articles for that concept that could be found by using it alone was calculated. RESULTS: Each of the 25 most searched-for concepts has 4 to 40 synonyms. Sixteen of the concepts required queries using two or more terms to find 75% of the available articles. Few searchers used a sufficient number of textword synonyms in their queries to return a complete listing of the available material. CONCLUSION: On the basis of this study, queries using only one or two textword terms are insufficiently sensitive to find all relevant journal articles about an IPSP concept. 相似文献
35.
Peripheral and central injections of recombinant human interleukin-1β (IL-1β) have been shown to decrease social exploration and to induce body weight loss in rats. To characterize the receptor mechanisms of these effects, we used as a tool a specific antagonist of the receptors of IL-1, IL-1ra. Intraperitoneal (i.p.) administration of IL-1ra (8 mg/kg) blocked the effect of i.p. injection of IL-1β (4 μg/rat) on social behaviour but not on body weight. Central administration of IL-1ra (60 μg/rat, i.c.v.) abrogated the effects of centrally administered IL-1β (30 ngn/rat, i.c.v.) on both social behaviour and body weight. Central injection of IL-1ra (4 μg/rat, i.c.v.) also attenuated the effects of i.p. administered IL-1β (4 μg/rat) on social behaviour but not on body weight. These results suggest that the effects of IL-1β on social behavior are mediated centrally and that its effect on the loss of body weight involves different receptor mechanisms. 相似文献
36.
The spatial and temporal pattern of expression of the protein products of immediate early genes (IEGs) c-fos, fos B, and egr-1 were mapped in medial preoptic area (MPOA) and ventral bed nucleus of stria terminalis (VBST) during maternal behavior in rats. Immunocytochemical analysis indicated significant increases in the number of cells expressing c-Fos after 2 h of pup exposure, while Fos B levels showed a delayed response, reaching maximal levels after 6 h. 相似文献
37.
T. Bendix A. F. Bendix E. Busch A. Jordan Tom Bendix MD 《Scandinavian journal of medicine & science in sports》1996,6(2):88-97
Conventional treatments have not slowed down the ever expanding low back pain (LBP) problem. Traditional treatment has most probably contributed to the growth of the problem. Therefore, in a search for new solutions, 'functional restoration' has been devised. In connection with chronic LBP the term has been associated with a full-day program lasting from 3 to 5 weeks. it includes multidisciplinary treatment of patients in groups with intensive physical and ergonomic training, psychological pain management, back school, as well as teaching in social/work related issues. The key concepts are 'acceptance of the pain', 'activity', 'self-responsibility', 'multidisciplinary' and 'quantitative functional evaluation (QFE)'. The latter is aimed so that the participants can feel the physical improvement, encouraging them to be able to go back to work, or at least to lead a more active life style. Several controlled studies suggest a lasting effect in terms of regaining their ability to work and improving pain behavior for a good part of disabled chronic LBP patients. However, it is noteworthy that randomized studies seemingly show poorer results than studies not employing randomized controls. 相似文献
38.
"Necklace olfactory glomeruli" form unique components of the rat primary olfactory system 总被引:3,自引:0,他引:3
A distinct subset of rat primary olfactory neurons was identified immunohistochemically by means of a polyclonal antibody against human placental antigen X-P2 (hPAX-P2), an incompletely characterized substance found in all estrogen-biosynthetic organs. The subset of olfactory receptor cells was distributed widely over the olfactory epithelium with some degree of concentration on the dorsocaudal walls of nasal subcavities. The subset formed unique "necklace olfactory glomeruli," which were composed of seven to nine solitary glomeruli located in the caudal end of the olfactory bulb. One of them was located in the "modified glomerular complex" reported to be involved in rat suckling behavior. The projectional patterns of the necklace olfactory system, albeit diffuse, indicated some degree of spatial correspondence between zones of olfactory epithelium and specific glomeruli. Axons emanating from neighboring cells can project to several glomerular loci. From the necklace olfactory system, an average of 150-200 receptor cells were estimated to converge onto a single necklace glomerulus. 相似文献
39.
Prevention of Postinfectious Asthma in Children by Reducing Self-Inoculatory Behavior 总被引:1,自引:0,他引:1
Cortey Donald L.; Gevirtz Richard; Nideffer Robert; Cummins Leo 《Journal of pediatric psychology》1987,12(4):519-531
Recent studies have shown that the spread of infectious nasalsecretions from hand-to-hand or hand-to-object, followed byself-inoculation is an efficient means of viral transmission.The present study was designed to investigate whether self-inoculationbehavior in asthmatic children could be reduced and, if so,whether this reduction would reduce the frequency of infectionand asthma. Sixteen subjects aged 4 to 8, all diagnosed withpostinfectious asthma, were assigned to a treatment (differentialreinforcement of other behavior and contingent education) orplacebo control condition. Results indicate that self-inoculatorybehavior, infection, and asthma were signjficantly reduced.These findings may indicate an important role for behavioralmedicine inpostinfectious asthma. 相似文献
40.
Nociceptin/orphanin FQ (N/OFQ), the endogenous ligand of the opioid receptor-like receptor or nociceptin receptor (NOP), has been shown to induce feeding, locomotion, anti-stress and anxiolytic effects in rodents after central nervous system injection. In this study, the effect of intracerebroventricular (icv) injection of N/OFQ on feeding and locomotion behavior was evaluated in male broiler-type chickens. The icv injection of N/OFQ caused a moderate but significant increase in feed intake similar to the classical opioid peptides in rats. It also increased feed pecking frequency and feeding time 1 h after injection. Stepping, wing flapping and preening were not affected by N/OFQ. These results suggest that N/OFQ can act within the central nervous system of chickens to increase feed intake. 相似文献