全文获取类型
收费全文 | 42163篇 |
免费 | 3056篇 |
国内免费 | 161篇 |
专业分类
耳鼻咽喉 | 500篇 |
儿科学 | 1397篇 |
妇产科学 | 570篇 |
基础医学 | 5114篇 |
口腔科学 | 580篇 |
临床医学 | 4369篇 |
内科学 | 9270篇 |
皮肤病学 | 705篇 |
神经病学 | 4030篇 |
特种医学 | 1689篇 |
外科学 | 7265篇 |
综合类 | 393篇 |
一般理论 | 81篇 |
预防医学 | 3265篇 |
眼科学 | 1167篇 |
药学 | 2257篇 |
中国医学 | 39篇 |
肿瘤学 | 2689篇 |
出版年
2023年 | 350篇 |
2022年 | 593篇 |
2021年 | 1582篇 |
2020年 | 780篇 |
2019年 | 1299篇 |
2018年 | 1575篇 |
2017年 | 1075篇 |
2016年 | 1177篇 |
2015年 | 1264篇 |
2014年 | 1771篇 |
2013年 | 2087篇 |
2012年 | 3516篇 |
2011年 | 3511篇 |
2010年 | 1901篇 |
2009年 | 1690篇 |
2008年 | 2821篇 |
2007年 | 2786篇 |
2006年 | 2679篇 |
2005年 | 2529篇 |
2004年 | 2486篇 |
2003年 | 2094篇 |
2002年 | 1915篇 |
2001年 | 281篇 |
2000年 | 216篇 |
1999年 | 276篇 |
1998年 | 373篇 |
1997年 | 322篇 |
1996年 | 249篇 |
1995年 | 237篇 |
1994年 | 176篇 |
1993年 | 176篇 |
1992年 | 124篇 |
1991年 | 136篇 |
1990年 | 110篇 |
1989年 | 88篇 |
1988年 | 72篇 |
1987年 | 75篇 |
1986年 | 70篇 |
1985年 | 74篇 |
1984年 | 82篇 |
1983年 | 97篇 |
1982年 | 112篇 |
1981年 | 84篇 |
1980年 | 57篇 |
1979年 | 36篇 |
1978年 | 42篇 |
1977年 | 39篇 |
1976年 | 30篇 |
1974年 | 34篇 |
1973年 | 33篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Edwin H. Preston He Xu Kiran K. Dhanireddy Jonathan P. Pearl Frank V. Leopardi Matthew F. Starost Douglas A. Hale Allan D. Kirk 《American journal of transplantation》2005,5(5):1032-1041
CD154-specific antibody therapy prevents allograft rejection in many experimental transplant models. However, initial clinical transplant trials with anti-CD154 have been disappointing suggesting the need for as of yet undetermined adjuvant therapy. In rodents, donor antigen (e.g., a donor blood transfusion), or mTOR inhibition (e.g., sirolimus), enhances anti-CD154's efficacy. We performed renal transplants in major histocompatibility complex-(MHC) mismatched rhesus monkeys and treated recipients with combinations of the CD154-specific antibody IDEC-131, and/or sirolimus, and/or a pre-transplant donor-specific transfusion (DST). Therapy was withdrawn after 3 months. Triple therapy prevented rejection during therapy in all animals and led to operational tolerance in three of five animals including donor-specific skin graft acceptance in the two animals tested. IDEC-131, sirolimus and DST are highly effective in preventing renal allograft rejection in primates. This apparently clinically applicable regimen is promising for human renal transplant trials. 相似文献
52.
53.
Carnitine, valproate, and toxicity 总被引:1,自引:0,他引:1
D L Coulter 《Journal of child neurology》1991,6(1):7-14
Carnitine is an important nutrient that is present in the diet (particularly in meat and dairy products) and is synthesized from dietary amino acids. It functions to assist long-chain fatty acid metabolism and to regulate the ratio of free coenzyme A to acylcoenzyme A in the mitochondrion. Carnitine deficiency occurs in primary inborn errors of metabolism, in nutritional deficiency, and in various other disorders including antiepileptic drug therapy. Valproate therapy is often associated with decreased carnitine levels and occasionally with true carnitine deficiency. Some experimental and clinical evidence links valproate-induced carnitine deficiency with hepatotoxicity, but this evidence is limited and inconclusive. Carnitine supplementation has been useful in some studies, but these data are also limited. Young children with neurologic disabilities taking multiple antiepileptic drugs may have the greatest risk for carnitine deficiency. Measurement of carnitine levels appears warranted in these patients and in patients with symptoms and signs of possible carnitine deficiency. 相似文献
54.
Anita Rachlis Jonathan Angel Marianne Harris Richard Lalonde Fiona Smaill Cecile Tremblay Chris Tsoukas Sharon Walmsley 《The Canadian Journal of Infectious Diseases & Medical Microbiology》2006,17(3):155-163
BACKGROUND AND OBJECTIVES: An eight-member group consisting of Canadian infectious disease and immunology specialists and a family physician with significant experience in HIV management was convened to update existing recommendations, specifically intended for use by Canadian HIV-treating physicians, on the appropriate use of enfuvirtide in HIV/AIDS patients with resistance to other antiretroviral drugs. METHODS: Evidence from the literature and expert opinions of the group members formed the basis of the guidelines. Comments on the draft guidelines were obtained from other physicians across Canada with HIV expertise. The final guidelines represent the group's consensus agreement. RESULTS AND CONCLUSIONS: The recommendations were developed to guide physicians in optimal practices in patient selection for enfuvirtide treatment and subsequent patient management. The issues considered include positive predictors of response to enfuvirtide, stage of disease, optimization of the background regimen, early indicators of enfuvirtide response, and patient education and support. 相似文献
55.
Hisako Ikeda Jonathan Robbins 《Documenta ophthalmologica. Advances in ophthalmology》1988,69(2):175-186
Anatomical and physiological segregation of neurons into ON (brightening detector) and OFF (darkening detector) channels in the retina and subsequent visual system ensure the high sensitivity required for contrast detection and spatial discrimination. This segregation is finest at the visual axis. Neurochemically, ON and OFF ganglion cells at the visual axis seem to be distinguished by different inhibitory transmitters but not excitatory transmitters. Microiontophoretic studies of inhibitory transmitters on the retinal ganglion cells in kittens and adult cats suggest that this neurochemical distinction is poor in immature ganglion cells at the visual axis. Initially both ON and OFF cells seem to be supplied by GABAergic, glycinergic, and catecholaminergic amacrine cells, but in adults, ON cells remain supplied only by GABAergic amacrines, while OFF cells are supplied by glycinergic amacrines. Postnatal elimination of multiple inputs and strengthening of the appropriate inputs, as seen in the central nervous system, also seem to occur at the retinal neurotransmitter synapses during development. 相似文献
56.
57.
Serum and Cerebrospinal Fluid Pharmacokinetics of Intravenous and Oral Lamivudine in Human Immunodeficiency Virus-Infected Children 总被引:3,自引:3,他引:0 下载免费PDF全文
Brigitta U. Mueller Linda L. Lewis Geoffrey J. Yuen Maureen Farley Amy Keller Joseph A. Church Jonathan C. Goldsmith David J. Venzon Marc Rubin Philip A. Pizzo Frank M. Balis 《Antimicrobial agents and chemotherapy》1998,42(12):3187-3192
We studied the pharmacokinetics of intravenously and orally administered lamivudine at six dose levels ranging from 0.5 to 10 mg/kg of body weight in 52 children with human immunodeficiency virus infection. A two-compartment model with first-order elimination from the central compartment was simultaneously fitted to the serum drug concentration-time data obtained after intravenous and oral administration. The maximal concentration at the end of the 1-h intravenous infusion and the area under the concentration-time curve after oral and intravenous administration increased proportionally with the dose. The mean clearance of lamivudine (± standard deviation) in the children was 0.53 ± 0.19 liter/kg/h (229 ± 77 ml/min/m2 of body surface area), and the mean half-lives at the distribution and elimination phases were 0.23 ± 0.18 and 2.2 ± 2.1 h, respectively. Clearance was age dependent when normalized to body weight but age independent when normalized to body surface area. Lamivudine was rapidly absorbed after oral administration, and 66% ± 25% of the oral dose was absorbed. Serum lamivudine concentrations were maintained above 1 μM for ≥8 h of 24 h on the twice daily oral dosing schedule with doses of ≥2 mg/kg. The cerebrospinal fluid drug concentration measured 2 to 4 h after the dose was 12% (range, 0 to 46%) of the simultaneously measured serum drug concentration. A limited-sampling strategy was developed to estimate the area under the concentration-time curve for concentrations in serum at 2 and 6 h. 相似文献
58.
Amy J Bastian Valerie E Kelly Fredy J Revilla Joel S Perlmutter Jonathan W Mink 《Movement disorders》2003,18(9):1000-1007
The purpose of this study was to determine the effects of unilateral versus bilateral subthalamic nucleus (STN) stimulation on quantitative measures of walking and reaching in Parkinson's disease (PD). We used kinematic measures and the Unified Parkinson's Disease Rating Scale (UPDRS) motor subscale (subscale III) to evaluate the movement of 6 people with PD who had bilateral STN stimulators implanted for at least 6 months and withheld their anti-parkinson medication for at least 8 hours. Subjects were studied with both stimulators off, one on, and both on. Kinematic data were collected as subjects walked, reached to a target, and were rated using the UPDRS motor subscale. STN stimulation improved walking speed and stride length, with the greatest benefit from bilateral stimulation. Reaching speed was improved by unilateral STN stimulation alone, with no additive effect of bilateral stimulation. UPDRS motor subscale ratings paralleled the kinematic findings. STN stimulation did not restore PD subjects' movements to the level of age-matched controls. Overall, these results provide further evidence that the basal ganglia pathways involved in control of walking and reaching may be distinct. We speculate that basal ganglia may influence walking through bilateral pedunculopontine projections and reaching through ipsilateral thalamocortical projections. Our findings also suggest that maximal improvement of walking requires bilateral rather than unilateral STN stimulation. 相似文献
59.
60.