全文获取类型
收费全文 | 36464篇 |
免费 | 3765篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 494篇 |
儿科学 | 1011篇 |
妇产科学 | 746篇 |
基础医学 | 5233篇 |
口腔科学 | 1369篇 |
临床医学 | 4188篇 |
内科学 | 7254篇 |
皮肤病学 | 405篇 |
神经病学 | 2931篇 |
特种医学 | 1266篇 |
外国民族医学 | 2篇 |
外科学 | 4811篇 |
综合类 | 941篇 |
一般理论 | 30篇 |
预防医学 | 3848篇 |
眼科学 | 1005篇 |
药学 | 2804篇 |
1篇 | |
中国医学 | 31篇 |
肿瘤学 | 1907篇 |
出版年
2021年 | 525篇 |
2020年 | 329篇 |
2019年 | 558篇 |
2018年 | 600篇 |
2017年 | 444篇 |
2016年 | 469篇 |
2015年 | 576篇 |
2014年 | 825篇 |
2013年 | 1220篇 |
2012年 | 1674篇 |
2011年 | 1761篇 |
2010年 | 943篇 |
2009年 | 926篇 |
2008年 | 1542篇 |
2007年 | 1646篇 |
2006年 | 1511篇 |
2005年 | 1579篇 |
2004年 | 1433篇 |
2003年 | 1383篇 |
2002年 | 1353篇 |
2001年 | 1091篇 |
2000年 | 1156篇 |
1999年 | 1066篇 |
1998年 | 390篇 |
1997年 | 326篇 |
1996年 | 364篇 |
1995年 | 337篇 |
1994年 | 336篇 |
1993年 | 337篇 |
1992年 | 854篇 |
1991年 | 839篇 |
1990年 | 865篇 |
1989年 | 772篇 |
1988年 | 728篇 |
1987年 | 730篇 |
1986年 | 688篇 |
1985年 | 702篇 |
1984年 | 527篇 |
1983年 | 484篇 |
1982年 | 300篇 |
1981年 | 315篇 |
1980年 | 285篇 |
1979年 | 470篇 |
1978年 | 379篇 |
1977年 | 302篇 |
1976年 | 282篇 |
1974年 | 374篇 |
1973年 | 361篇 |
1972年 | 297篇 |
1971年 | 311篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
C4 concentrations and C4 deficiency alleles in systemic lupus erythematosus. 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Annals of the rheumatic diseases》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In a study of 66 patients with systemic lupus erythematosus (SLE) and 80 controls it was found that the presence of two deficiency (null) alleles of C4 had a significant effect on mean C4 concentrations in serum. In six controls who each had two C4 null alleles the mean C4 concentration in serum was 56% lower than in 43 controls without C4 null alleles; the nadir of the C4 concentration in four patients with SLE with two null alleles was also lower by a mean of 55% than in 32 patients who did not have null alleles. Reduced production of C4 allotypes in subjects with two null alleles may be an important determinant of total C4 concentration in patients with SLE. For optimal interpretation of C4 concentrations in SLE, C4 allotyping appears to be indicated, particularly to identify patients who have two null alleles of C4. 相似文献
22.
Prospective randomized comparison of mezlocillin therapy alone with combined ampicillin and gentamicin therapy for patients with cholangitis 总被引:3,自引:0,他引:3
W B Gerecht N K Henry W W Hoffman S M Muller N F LaRusso J E Rosenblatt W R Wilson 《Archives of internal medicine》1989,149(6):1279-1284
Forty-six patients with cholangitis were randomized to receive therapy with mezlocillin sodium (24 patients) or a combination of ampicillin sodium--gentamicin sulfate (22 patients). The biliary concentration of mezlocillin was 112 times higher than that of ampicillin and 778 times higher than that of gentamicin. The ratio of the concentration in serum or bile over the minimum inhibitory concentration against aerobic gram-negative bacilli (therapeutic index) was higher for mezlocillin than for either ampicillin or gentamicin. Twenty (83%) of 24 patients were cured following mezlocillin therapy compared with 9 (41%) of 22 patients after ampicillin-gentamicin therapy. The 3 patients with superinfection were in the ampicillin-gentamicin arm of the study. Fewer toxic or adverse effects occurred in association with mezlocillin treatment than with ampicillin-gentamicin treatment. Mezlocillin therapy was more effective, less toxic, and less expensive than treatment with ampicillin and gentamicin for patients with cholangitis. 相似文献
23.
24.
Brain serotonin transporter binding in non-depressed patients with Parkinson's disease 总被引:2,自引:0,他引:2
M. Guttman I. Boileau J. Warsh J. A. Saint-Cyr N. Ginovart T. McCluskey S. Houle A. Wilson E. Mundo P. Rusjan J. Meyer S. J. Kish 《European journal of neurology》2007,14(5):523-528
Early post-mortem data suggest that damage to brain serotonin neurones might play a role in some features (e.g., depression) of Parkinson's disease (PD). However, it is not known whether such damage is a typical characteristic of living patients with PD or whether the changes are regionally widespread. To address this question we measured, by positron emission tomography imaging, levels of the brain serotonin transporter (SERT), a marker for serotonin neurones, as inferred from binding of [11 C]-3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl)-benzonitrile (DASB), a second generation SERT radioligand, in subcortical and cerebral cortical brain areas of clinically advanced non-depressed (confirmed by structured psychiatric interview) patients with PD. SERT binding levels in PD were lower than those in controls in all examined brain areas, with the changes statistically significant in orbitofrontal cortex (−22%), caudate (−30%), putamen (−26%), and midbrain (−29%). However, only a slight non-significant reduction (−7%) was observed in dorsolateral pre-frontal cortex, an area implicated in major depression. Our imaging data suggests that a modest, regionally widespread loss of brain serotonergic innervation might be a common feature of advanced PD. Further investigation will be required to establish whether SERT binding is more or less decreased in those patients with PD who also have major depressive disorder. 相似文献
25.
Four behavioural tests have been used to study the antinociceptive effects of electrical stimulation of the anterior pretectal nucleus (APtN) in the rat. The antinociceptive effects of stimulating this nucleus, which lies dorsally in the posterior diencephalon, have recently been studied extensively but always using briefly applied heat stimuli. It is reported here that APtN stimulation effectively inhibited responses to briefly applied noxious pressure and longer-lasting noxious chemical (formalin) stimuli. Although the tail-flick reflex to noxious heat was very potently depressed by APtN stimulation, responses to noxious heat in the hot-plate test were not. Three doses of morphine were also studied with each test and it was concluded that 15 sec of 35 microA r.m.s. current into the APtN was as effective as 3-5 mg/kg morphine s.c. in the rat. 相似文献
26.
27.
Factitious illness in children is a phenomenon that results in adverse consequences for the child. Munchausen by proxy is a factitious disorder, first described by Meadow (1977), in which a parent induces or creates the appearance of illness in the child. This article highlights the importance of social work skills in the identification and management of this syndrome, and proposes a format for decision making at various points in the process. 相似文献
28.
Sérgio Carreir?o Leandro Pereira Marcelo Wilson Rocha Almeida 《Aesthetic plastic surgery》2009,33(3):445-451
Surgical procedures for the mammary region currently are assuming an important role in body-contouring surgery. Enhancement
of results is a constant challenge to the plastic surgeon. A simple and efficient maneuver for resection of the breast’s lateral
pole based on the mammoplasty technique of Professor Ivo Pitanguy is described.
This study realized at the Private Clinic Sérgio Carreir?o, Rio de Janeiro, RJ, Brazil. 相似文献
29.
David H. Wilson Catherine R. Chittleborough Kerry Kirke Janet F. Grant Richard E. Ruffin 《Sozial- und Pr?ventivmedizin》2004,13(5):406-412
Objectives: Heavy smokers are a segment of the smoking population who are at increased risk of smoking-related morbidity and least likely to achieve cessation. This study identifies the impact of heavy smoking on quality of life by gender and describes the subpopulation for improved targeting.Methods: South Australian representative population data (n = 3010) was used to compare the health-related quality of life status of male and female heavy smokers as assessed by the SF-36. 相似文献
30.
A. Bogaards PhD H.J.C.M. Sterenborg B.C. Wilson 《Photodiagnosis and Photodynamic Therapy》2007,4(3):170-178
With the advent of molecular-targeted fluorescent markers, there is a renewed interest in fluorescence quantification methods that are based on continuous wave excitation and multi-spectral image acquisition. However, little is known about their in vivo quantification performance. We reviewed the performance of five selected methods by analytically describing these and varying input parameters of irradiance, excitation geometry, collection efficiency, autofluorescence, melanin content, blood volume, blood oxygenation and tissue scattering using optical properties representing those for human skin. We identified one method that corrects for variations in all parameters. This requires image acquisition before and after marker administration, under identical geometry. Hence, it is suited for applications where the site of interest can be relocated (e.g. anaesthetized animals and dermatology). For applications where relocation is not possible, we identified a second method where the uncertainty in the fluorescence signal was ±20%. Hence, use of these methods can substantially aid in vivo fluorescence quantification compared to use of the raw fluorescence signal, as this changed by more than 3 orders of magnitude. Since these methods can be computed in real-time, they are of particular interest for applications where direct feedback is critical, as diagnostic screening or image-guided surgery. 相似文献