全文获取类型
收费全文 | 95214篇 |
免费 | 42621篇 |
国内免费 | 994篇 |
专业分类
耳鼻咽喉 | 1615篇 |
儿科学 | 4459篇 |
妇产科学 | 1060篇 |
基础医学 | 17761篇 |
口腔科学 | 5381篇 |
临床医学 | 14708篇 |
内科学 | 25784篇 |
皮肤病学 | 7702篇 |
神经病学 | 14188篇 |
特种医学 | 2901篇 |
外国民族医学 | 7篇 |
外科学 | 15748篇 |
综合类 | 2543篇 |
现状与发展 | 1篇 |
一般理论 | 32篇 |
预防医学 | 5203篇 |
眼科学 | 1721篇 |
药学 | 7397篇 |
8篇 | |
中国医学 | 1707篇 |
肿瘤学 | 8903篇 |
出版年
2024年 | 66篇 |
2023年 | 317篇 |
2022年 | 699篇 |
2021年 | 2066篇 |
2020年 | 5589篇 |
2019年 | 11312篇 |
2018年 | 10640篇 |
2017年 | 11878篇 |
2016年 | 12475篇 |
2015年 | 12604篇 |
2014年 | 12700篇 |
2013年 | 13220篇 |
2012年 | 5497篇 |
2011年 | 5556篇 |
2010年 | 9817篇 |
2009年 | 5994篇 |
2008年 | 2998篇 |
2007年 | 1873篇 |
2006年 | 1855篇 |
2005年 | 1611篇 |
2004年 | 1365篇 |
2003年 | 1328篇 |
2002年 | 1274篇 |
2001年 | 1277篇 |
2000年 | 1180篇 |
1999年 | 815篇 |
1998年 | 330篇 |
1997年 | 308篇 |
1996年 | 222篇 |
1995年 | 203篇 |
1994年 | 165篇 |
1993年 | 130篇 |
1992年 | 203篇 |
1991年 | 169篇 |
1990年 | 131篇 |
1989年 | 114篇 |
1988年 | 140篇 |
1987年 | 128篇 |
1986年 | 89篇 |
1985年 | 91篇 |
1984年 | 63篇 |
1983年 | 43篇 |
1982年 | 36篇 |
1981年 | 25篇 |
1980年 | 20篇 |
1979年 | 40篇 |
1978年 | 26篇 |
1977年 | 18篇 |
1975年 | 20篇 |
1974年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
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
42.
Monoamine oxidase (MAO) A and B play an important role in regulating levels of biogenic amines. MAO A and B cDNAs have been cloned and the deduced amino acids share 73% sequence identity. The genes for MAOA and B are comprised of 15 exons interspersed by 14 introns, span at least 60 kb and exhibit identical exon-intron organization. These findings suggest that the MAOA and MAOB genes are derived from the duplication of a common ancestral gene. The core promoter region of MAOA is comprised of two 90 bp repeats, each of which contains two Spl elements and lacks a TATA box. The MAOB core promoter region contains two sets of overlapping Spl sites which flank a CACCC element all upstream of a TATA box. The different organization of the MAOA and MAOB promoters may underlie their different cell and tissue specific expression. 相似文献
43.
44.
45.
Couples in remarriages with stepchildren are a significant portion of the marriage population and have unique educational needs regarding aspects of couple functioning within the context of stepfamily development. From a review of the literature, we examine current curricula focused on these couples. Information is offered on implementation issues regarding recruitment, delivery context, facilitator and participant characteristics, and evaluation. 相似文献
46.
47.
48.
Antiproliferative Activity Against MCF‐7 Breast Cancer Cells by Diamino‐Triazaspirodiene Antifolates
Xiang Ma Renee Ser‐Peng Woon Paul Chi‐Lui Ho Wai‐Keung Chui 《Chemical biology & drug design》2009,74(3):322-326
Two triazaspirodienes, having similar phenoxy propyloxy side chain, were identified as potent mammalian dihydrofolate reductase inhibitors; one having a 6,5‐spiro bicyclic ring system (IC50 = 2.3 nm ) and the other a 6,6‐spiro bicyclic system (IC50 = 6.9 nm ). They also showed more than 50% antiproliferative activity against the MCF‐7 breast cancer cells at 20 μm . This study demonstrated the potential lead of the diamino‐triazaspirodienes in anticancer chemotherapeutical agents’ discovery. 相似文献
49.
Context Residents in all disciplines serve as clinical teachers for medical students. Since the 1970s, there has been increasing evidence to demonstrate that residents wish to teach and that they respond positively to formal teacher training. Effective resident‐as‐teacher (RaT) programmes have resulted in improved resident teaching skills. Current evidence, however, is not clear about the specific features of an effective RaT programme. Objectives This study was performed in order to investigate the effectiveness of RaT programmes on resident teaching abilities and to identify the features that ensure success. Methods of assessment used to ascertain the effectiveness of RaT programmes are also explored. Methods The literature search covered the period between 1971 and 2008. Articles focusing on improving resident teaching skills were included. Each study was reviewed by two reviewers and data were collected using a standard abstraction summary sheet. Study outcomes were graded according to a modified Kirkpatrick's model of educational outcomes. Results Twenty‐nine studies met review inclusion criteria. Interventions included workshops, seminars, lectures and teaching retreats. Twenty‐six studies used a pre‐ and post‐intervention outcome comparison method. Subjective outcome measures included resident self‐evaluation of teaching skills or evaluation by medical students, peers and faculty members. Objective outcome measures included written tests, evaluation of teaching performance by independent raters and utilisation of objective structured teaching examinations. One study objectively measured learning outcomes at the level of medical students, utilising the results of an objective structured clinical examination. Overall resident satisfaction with RaT programmes was high. Participants reported positive changes in attitudes towards teaching. Participant knowledge of educational principles improved. Study methodologies allowed for significant risks of bias. Conclusions More rigorous study designs and the use of objective outcome measures are needed to ascertain the true effectiveness of RaT programmes. Future research should focus on determining the impact of RaT programmes on learning achievement at the level of medical students. 相似文献
50.
Serum IgA and IgG functional antibodies and their subclasses to Streptococcus pneumoniae capsular antigen found in two aged‐matched cohorts of children with and without otitis media with effusion The relationship between acute otitis media and otitis media with effusion (OME) is uncertain and the aetiology of OME is multifactorial. Otitis media with effusion may be an inflammatory condition; both bacteria and viral infections could play a part in this inflammation. The four bacteria Streptococcus pneumoniae, Haemophilus influenza, Staphylococcus aureus and Branhamella catarrhalis cause 60% of the infections whereas S. pneumoniae accounts for up to 35%. IgA provides the dominant surface response to polysaccharide and lipopolysaccharide antigens, of which IgA2 is the main subclass. Once the mucosa has been breached, most protection is provided by IgG. IgG2 acts mainly against bacterial capsular antigens. This study looked at two groups of 50 children with and without OME who were aged between 3 and 10 years. The aims were to determine if, firstly, the levels of the serum immunoglobulins were different in the two groups, secondly whether these children made the appropriate antibody response to the capsular antigen to S. pneumoniae (PCP), and finally if there was a delay in the maturity of the IgA response. The total IgG, IgA and all subclass levels were measured using radial immunodiffusion. Levels of functional IgA and IgG were measured using ELISAs (25 patients in each group). The results were analysed with non‐parametric tests. The immunoglobulin levels were within the normal levels for both groups. There were very good correlations between the IgG total anti‐PCP and the IgG2 anti‐PCP (R > 0.9, p = 0.001). There was a good correlation between the levels of both IgG total and IgG2 anti‐PCP against IgA total anti‐PCP in both groups (R > 0.85, p > 0.01). This confirms a normal antibody response between both groups of patients. The ages of the controls and patients (50 samples) were correlated with increasing titres of circulating functional antibodies (P = 0.001). This is highly suggestive of a normal age‐related response. In conclusion, the findings were contradictory to our original hypothesis that there is a subtle difference in surface protection between children with and without OME. We believe that a previous history of recurrent acute otitis media is unrelated to the development of OME after 3 years of age. 相似文献