全文获取类型
收费全文 | 146982篇 |
免费 | 46129篇 |
国内免费 | 154篇 |
专业分类
耳鼻咽喉 | 2124篇 |
儿科学 | 6901篇 |
妇产科学 | 2340篇 |
基础医学 | 24927篇 |
口腔科学 | 6373篇 |
临床医学 | 21639篇 |
内科学 | 35515篇 |
皮肤病学 | 8674篇 |
神经病学 | 20262篇 |
特种医学 | 3916篇 |
外国民族医学 | 1篇 |
外科学 | 21186篇 |
综合类 | 1038篇 |
一般理论 | 111篇 |
预防医学 | 12994篇 |
眼科学 | 2279篇 |
药学 | 10063篇 |
2篇 | |
中国医学 | 1100篇 |
肿瘤学 | 11820篇 |
出版年
2023年 | 677篇 |
2022年 | 929篇 |
2021年 | 3200篇 |
2020年 | 6164篇 |
2019年 | 12506篇 |
2018年 | 12067篇 |
2017年 | 12844篇 |
2016年 | 13569篇 |
2015年 | 13595篇 |
2014年 | 14117篇 |
2013年 | 15761篇 |
2012年 | 9326篇 |
2011年 | 9445篇 |
2010年 | 11718篇 |
2009年 | 7768篇 |
2008年 | 6378篇 |
2007年 | 5347篇 |
2006年 | 5291篇 |
2005年 | 4873篇 |
2004年 | 4652篇 |
2003年 | 4345篇 |
2002年 | 4123篇 |
2001年 | 1717篇 |
2000年 | 1468篇 |
1999年 | 1027篇 |
1998年 | 772篇 |
1997年 | 598篇 |
1996年 | 592篇 |
1995年 | 524篇 |
1994年 | 448篇 |
1993年 | 418篇 |
1992年 | 548篇 |
1991年 | 512篇 |
1990年 | 513篇 |
1989年 | 439篇 |
1988年 | 389篇 |
1987年 | 373篇 |
1986年 | 313篇 |
1985年 | 345篇 |
1984年 | 307篇 |
1983年 | 258篇 |
1982年 | 266篇 |
1981年 | 232篇 |
1980年 | 222篇 |
1979年 | 233篇 |
1978年 | 208篇 |
1977年 | 157篇 |
1976年 | 144篇 |
1974年 | 161篇 |
1973年 | 143篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Sylvia J T Jansen Wilma Otten Anne M Stiggelbout 《Journal of clinical oncology》2004,22(15):3181-3190
PURPOSE: Many studies have determined cancer patients' preferences for adjuvant therapy, for example, by asking patients the extent of benefit they would need in order to accept the therapy. However, little is known about the determinants that influence these preferences. Our research goal was to explore which determinants underlie patients' preferences by means of a literature review. METHODS: PubMed searches were conducted to identify studies in which cancer patients' preferences for adjuvant therapy had been elicited by means of a treatment preference instrument. Twenty-three papers were evaluated with regard to reported relationships between preferences and potential determinants. A total of 40 determinants were recorded and classified into one of seven categories: (1) treatment-related determinants, (2) sociodemographic characteristics and current quality of life, (3) clinical characteristics, (4) measurement instrument-related determinants, (5) time-related determinants, (6) cognitive/affective determinants, and (7) specialist-related determinants. Results: The benefit and toxicity of treatment, experience of the treatment, and having dependents (eg, children) living at home were important determinants of patients' preferences. Furthermore, qualitative data suggested that cognitive/affective and specialist-related determinants might have a large impact on patients' treatment preferences. CONCLUSION: Our results show that patients' preferences cannot fully be explained on the basis of treatment-related determinants and patient and clinical characteristics. More research is needed in the area of cognitive/affective and specialist-related determinants because of the lack of quantitative results. Furthermore, we recommend carrying out larger studies in which the (internal) relationships between determinants and preferences are assessed in the context of a cognitive cost-benefit model. 相似文献
42.
OBJECTIVE: Based on recent safety and efficacy data, combined with the known pharmacokinetic parameters of aminoglycosides in the newborn, once-daily gentamicin should be preferable to the many other dosing regimens currently in use. Although there are growing data to support its use in term newborns, experience with preterm infants is more limited. In our Neonatal Intensive Care Unit, we experienced difficulties regarding complicated dosing regimens, actual dosing errors, and the tendency to check trough and peak levels around the third dose for infants receiving only a 48 hour course. Therefore, we conducted a quality improvement initiative in which we developed and tested a clinical practice guideline for the use of once-daily gentamicin for preterm and term infants that we hoped would yield trough and peak levels in our target range. METHODS: We combined a review of the published English language literature with pharmacokinetic analysis of our own data prior to initiation of this new regimen to design the following dosing regimen: <35 weeks gestation: 3 mg/kg q 24 hours, > or =35 weeks gestation: 4 mg/kg q 24 hours. Our goal serum levels were a trough < or =2 microg/ml and a peak between 6 and 12 microg/ml. We collected and analyzed trough and peak levels from all infants receiving this dosing regimen in the first week of life for at least 72 hours between 3/1/99 and 12/31/00. RESULTS: In total, 214 babies met our inclusion criteria, 75 of whom were <35 weeks gestation. 100% of babies of all gestational ages had a nontoxic trough level. For infants <35 weeks gestation, 79% had a therapeutic peak level, with a mean value of 6.8 microg/ml. For infants of at least 35 weeks gestation, 93% had a therapeutic peak level, with a mean value of 8.4 microg/ml. 92% of nontherapeutic peaks were too low. CONCLUSION: This study of once-daily gentamicin represents the largest sample size of pre-term infants published to date. The proposed regimen is simple and yields a high proportion of desirable levels. We recommend it for use in preterm and term newborns. 相似文献
43.
44.
Aims To measure the prevalence of low high‐density lipoprotein (HDL)‐cholesterol (men < 1.03 mmol/l; women < 1.29 mmol/l) in European Type 2 diabetic patients receiving treatment for dyslipidaemia. Methods The pan‐European Survey of HDL‐cholesterol measured lipids and other cardiovascular risk factors in 3866 patients with Type 2 diabetes and 4436 non‐diabetic patients undergoing treatment for dyslipidaemia in 11 European countries. Results Diabetic patients were more likely to be obese or hypertensive than non‐diabetic patients. Most patients received lifestyle interventions (87%) and/or a statin (89%); treatment patterns were similar between groups. Diabetic patients had [means (SD)] lower HDL‐cholesterol [1.22 (0.37) vs. 1.35 mmol/l (0.44) vs. non‐diabetic patients, P < 0.001] and higher triglycerides [2.32 (2.10) vs. 1.85 mmol/l (1.60), P < 0.001]. More diabetic vs. non‐diabetic patients had low HDL‐cholesterol (45% vs. 30%), high triglycerides (≥ 1.7 mmol/l; 57% vs. 42%) or both (32% vs. 19%). HDL‐cholesterol < 0.9 mmol/l was observed in 18% of diabetic and 12% of non‐diabetic subjects. Differences between diabetic and non‐diabetic groups were slightly greater for women. LDL‐ and total cholesterol were lower in the diabetic group [3.02 (1.05) vs. 3.30 mmol/l (1.14) and 5.12 (1.32) vs. 5.38 mmol/l (1.34), respectively, P < 0.001 for each]. Conclusions Low HDL‐cholesterol is common in diabetes: one in two diabetic women has low HDL‐cholesterol and one diabetic man in four has very low HDL‐cholesterol. Management strategies should include correction of low HDL‐cholesterol to optimize cardiovascular risk in diabetes. 相似文献
45.
Anthropology, and its supposed operationalisation within transcultural nursing, is becoming increasingly prominent in educational curricula in the U.K. This increase in interest is driven both by governmental pressure to provide more culturally appropriate care, and an intuitive notion that anthropology, nursing and other related professions such as midwifery have a common basis of mutually overlapping and re-enforcing theory and practice. This paper explores the question of whether there is a natural alliance between anthropology, and the applied aspects of health care disciplines such as nursing and midwifery, by examining some of the concepts underlying each discipline, and the ways in which these concepts are applied in practice. Anthropology is the study of culture, and it is suggested that a more complete understanding of this central concept is essential if it is to be utilised in the applied disciplines encompassed by the practice of nursing and midwifery. 相似文献
46.
L D Kelly M Gaynon 《Canadian journal of ophthalmology. Journal canadien d'ophtalmologie》1990,25(4):208-209
Bacteroides fragilis is an infrequent anaerobic ocular pathogen. Nevertheless, this organism is of particular significance because it may be resistant to many antibiotics that are typically effective against anaerobes. We present what is to the best of our knowledge the first reported case of B. fragilis endophthalmitis. The endophthalmitis presented in a 95-year-old man following extracapsular cataract extraction with posterior chamber intraocular lens implantation. 相似文献
47.
Summary UK health policy requires child and adolescent mental health service providers to demonstrate that their services are effective.
The FOCUS project has been developed to improve the availability and accessibility of research evidence and innovation, to
support purchasers in the effective commissioning of services and to help providers base service provision on evidence of
effectiveness and develop methods of evaluation. 相似文献
48.
Dr. Andrew G. Bostom M.D. Dr. Anne L. Hume Pharm.D. Dr. Charles B. Eaton M.D. Dr. Joseph P. Laurino Ph.D. Ms. Lisa R. Yanek B.A. Ms. Mary S. Regan B.S. Mr. William H. McQuade M.P.H. Dr. Wendy Y. Craig Ph.D. Ms. Gayle Perrone M.B.A. Dr. Paul F. Jacques Sc.D. 《Pharmacotherapy》1995,15(4):458-464
Study Objective . To determine the efficacy of high-dose ascorbate supplementation in lowering lipoprotein(a) [Lp(a)] levels in patients with premature coronary heart disease (CHD). Design . Randomized, double-blind, placebo-controlled trial. Setting . Outpatient clinic. Patients . Forty-four patients with documented premature CHD. defined as confirmed myocardial infarction and/or angiographically determined stenosis of 50% or greater in at least one major coronary artery before age 60 years. Interventions . Patients were block randomized on the basis of age, gender, and screening Lp(a) concentrations to receive ascorbate 4.5 g/day or placebo for 12 weeks. Measurements and Main Results . High-dose ascorbate was well tolerated and produced a marked elevation in mean plasma ascorbate levels (+1.2 mg/dl; p<0.001). Multiple linear regression analysis revealed no significant effect of supplementation on postintervention Lp(a) levels (p=0.39) in a model that included treatment group assignment, and baseline Lp(a) levels. Conclusions . Our findings do not support a clinically important lowering effect of high-dose ascorbate on plasma Lp(a) in patients with premature CHD. 相似文献
49.
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
50.
Oral administration of myelin basic protein (MBP) inhibits clinical and histopathological manifestations of experimental autoimmune encephalomyelitis (EAE), but only partially reduces serum anti-MBP antibody titers. We report here that orally administered MBP alters the isotypic distribution of anti-MBP antibody-forming cells (AFC) among various lymphoid tissues, with the most profound differences seen in mucosal tissues. We observed an isotype-selective reduction in anti-MBP IgA but not IgM AFC frequencies in Peyer's patches. The anti-MBP IgA AFC frequencies could be reconstituted by addition of interleukin 4 (IL-4) and interleukin 5 (IL-5). The cytokines did not appear to generate de novo responses since no increases in anti-MBP IgA AFC frequencies were observed in control cultures. These results indicate that decreased antibody production, as a result of oral antigen administration, can be reversed by exposure to the appropriate cytokines. 相似文献