全文获取类型
收费全文 | 25660篇 |
免费 | 1854篇 |
国内免费 | 138篇 |
专业分类
耳鼻咽喉 | 90篇 |
儿科学 | 1485篇 |
妇产科学 | 605篇 |
基础医学 | 2215篇 |
口腔科学 | 110篇 |
临床医学 | 2501篇 |
内科学 | 7841篇 |
皮肤病学 | 463篇 |
神经病学 | 2007篇 |
特种医学 | 224篇 |
外科学 | 2950篇 |
综合类 | 607篇 |
现状与发展 | 1篇 |
一般理论 | 6篇 |
预防医学 | 2226篇 |
眼科学 | 954篇 |
药学 | 1115篇 |
2篇 | |
中国医学 | 50篇 |
肿瘤学 | 2200篇 |
出版年
2024年 | 41篇 |
2023年 | 248篇 |
2022年 | 228篇 |
2021年 | 347篇 |
2020年 | 338篇 |
2019年 | 119篇 |
2018年 | 466篇 |
2017年 | 496篇 |
2016年 | 550篇 |
2015年 | 534篇 |
2014年 | 446篇 |
2013年 | 709篇 |
2012年 | 1997篇 |
2011年 | 2271篇 |
2010年 | 795篇 |
2009年 | 774篇 |
2008年 | 2436篇 |
2007年 | 2316篇 |
2006年 | 2003篇 |
2005年 | 2088篇 |
2004年 | 2042篇 |
2003年 | 2080篇 |
2002年 | 1673篇 |
2001年 | 1250篇 |
2000年 | 284篇 |
1999年 | 137篇 |
1998年 | 199篇 |
1997年 | 116篇 |
1996年 | 90篇 |
1995年 | 57篇 |
1994年 | 72篇 |
1993年 | 36篇 |
1992年 | 41篇 |
1991年 | 32篇 |
1990年 | 37篇 |
1989年 | 36篇 |
1988年 | 36篇 |
1987年 | 39篇 |
1986年 | 33篇 |
1985年 | 24篇 |
1984年 | 24篇 |
1983年 | 11篇 |
1982年 | 17篇 |
1981年 | 19篇 |
1980年 | 12篇 |
1979年 | 8篇 |
1978年 | 6篇 |
1974年 | 4篇 |
1970年 | 6篇 |
1957年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
32.
33.
What Is Sufficient Evidence for the Reliability and Validity of Patient-Reported Outcome Measures? 总被引:1,自引:0,他引:1
34.
35.
诸暨麻疹疫苗免疫持久性研究协作组 《中华流行病学杂志》1987,8(2):92-95
1985年2~6月间,研究基地五个乡发生显性麻疹122例,为基地建立以来前11年病例总数的9.4倍,87.7%的病例集中在小学和幼儿园。
显性感染仅见于麻疹HI抗体<1:2者。不同原因导致麻疹HI抗体<1:2者,在暴露于自然麻疹后,原发免疫失败全表现为显性感染,继发免疫失败主要表现为隐性感染或不感染。
本次麻疹流行,再次证实当人群麻疹HI抗体阳性率在85%左右、阳性GMT为10.8左右的免疫水平时,虽有传染源输入,除个别易感者特别集中的单位可酿成较高罹患率外。不致造成大的流行。此外还观察到研究观察对象在充分暴露于自然麻疹后可获高达75%的隐性感染率,认为这对巩固和提高人群免疫水平具有积极意义,因而实行一次有效的麻疹疫苗接种在目前是可行的。 相似文献
显性感染仅见于麻疹HI抗体<1:2者。不同原因导致麻疹HI抗体<1:2者,在暴露于自然麻疹后,原发免疫失败全表现为显性感染,继发免疫失败主要表现为隐性感染或不感染。
本次麻疹流行,再次证实当人群麻疹HI抗体阳性率在85%左右、阳性GMT为10.8左右的免疫水平时,虽有传染源输入,除个别易感者特别集中的单位可酿成较高罹患率外。不致造成大的流行。此外还观察到研究观察对象在充分暴露于自然麻疹后可获高达75%的隐性感染率,认为这对巩固和提高人群免疫水平具有积极意义,因而实行一次有效的麻疹疫苗接种在目前是可行的。 相似文献
36.
R. Nickel S. Lau B. Niggemann C. Sommerfeld U. Wahn the German Multicenter Allergy Study Group 《Clinical and experimental allergy》2002,32(9):1274-1277
BACKGROUND: Bronchial responsiveness (BR) to histamine or methacholin is a common finding in adult non-asthmatic patients with allergic rhinitis. OBJECTIVE: We tested whether BR is also present in children with a comparatively short history of allergic rhinitis in a paediatric cohort. METHODS: We performed pulmonary function tests and histamine challenges in a total of 654 children (age 7 years, participants of the German Multicenter Allergy Study) and compared PC20 FEV1 values in children with asthma, allergic rhinitis, asymptomatic allergic sensitization and non-atopic controls. RESULTS: Most pronounced BR to histamine was observed in allergic asthmatics (n = 28), irrespective of the presence or absence of allergic rhinitis. Furthermore, PC(20)FEV(1) values in non-asthmatic children with allergic rhinitis (n = 24) were not significantly different from those seen in asymptomatic atopic (n = 54) or non-atopic controls (n = 92). CONCLUSIONS: In contrast to adult study populations, 7-year-old non-asthmatic children with allergic rhinitis do not show a higher degree of BR than asymptomatic atopic or non-atopic controls. Therefore, secondary preventive measures in non-asthmatic children with allergic rhinitis (such as regular local anti-inflammatory therapy or specific immunotherapy) should be studied and applied more intensely to prevent bronchial hyper-responsiveness (BHR) and asthma in this high-risk group. 相似文献
37.
Coppo R; Cirina P; Amore A; Sinico R; Radice A; Rollino C; the Italian Group of Renal Immunopathology Collaborative Study on Henoch-Schonlein purpura in adults f; children i 《Nephrology, dialysis, transplantation》1997,12(11):2269-2276
Background: The presence and the pathogenetic role of
circulating IgA reacting with neutrophil cytoplasmic antigens (IgA-ANCA) in
patients with Henoch-Schonlein purpura (HSP) is still debated. This study
was aimed to investigate some characteristics of serum IgA and
macromolecular IgA in HSP patients, focusing on IgA-ANCA.
Methods: Eighty-seven HSP patients with biopsy proved
renal involvement (51 adults and 36 children) enrolled in a multicentre
study of the Italian Group of Immunopathology were investigated.
Results: Significantly high levels of IgA immune
complexes were found in both adults (P <0.05) and children (P
<0.01), while the binding of IgA to jacalin, was significantly low
in children with HSP (P <0.01) only. Two series of ELISA were done
for IgA-ANCA, in two different laboratories. Increased binding to PMN crude
extracts (P <0.01) without any modification in IgA binding to
proteinase 3 was found by either specific ELISA. Conversely, the binding of
IgA to myeloperoxidase (MPO) was found to be significantly (P <0.05)
increased with positive values in 25% of patients by one assay only. Three
of four sera with positive IgA-MPO ANCA exhibited binding in Western-blot
studies with the MPO preparation used in ELISA to a 28-kDa species.
D-galactose and N-acetyl-glucosamine decreased the binding of serum IgA to
MPO more in HSP than in controls (P <0.05).
Conclusions: The conflicting reports on IgA-ANCA may
reflect some atypical characteristics of the reaction which can be detected
only by some ELISAs. We suggest that not an antigen-antibody reaction but a
lectinic interaction due to abnormal composition of IgA carbohydrate side
chains may account for the IgA-ANCA reaction in patients with HSP
nephritis. 相似文献
38.
A study of the relationship between the delivery to cord clamping interval and the time of cord separation 总被引:1,自引:0,他引:1
A randomised controlled trial of 554 women was carried out to compare the effects of late and early umbilical cord clamping on the time of cord separation. In addition data were collected on maternal and neonatal outcomes. There were no significant differences between the two groups in the duration of cord adherence and neonatal and maternal outcomes. There appeared to be a higher rate of jaundice in the late clamped group which did not reach statistical significance. There was an unexpectedly higher rate of breast feeding at home in the late clamped group which did reach statistical significance. Overall the trial provides no clear evidence for the benefit of early cord clamping (the current policy as part of the active management of the third stage in the UK) on the outcomes considered. 相似文献
39.
Solveig B. Larsen Aleksander Giwercman Marcello Spanò Jens P. Bonde The ASCLEPIOS Study Group 《Reproductive toxicology (Elmsford, N.Y.)》1998,12(6):391-589
It was hypothesized that occupational exposure to pesticides during a spraying season causes changes in semen quality that might be detected in a longitudinal study. We analyzed the within-person changes in semen quality and reproductive hormones across a spraying season in groups of farmers using and not using pesticides. A total of 248 men collected two semen samples (participation rate: 32%). The median sperm concentration declined significantly from the first to the second sample in both groups, but there was no statistical difference in the decline between the two groups, unadjusted or adjusted. Only minor changes were found in sperm morphology, vitality, motility, sperm chromatin denaturation (SCSA), and reproductive hormones, and the differences in changes between the two groups were nonsignificant, or, in the opposite direction to the expected. There was no relation between the changes in sperm parameters in relation to pesticide exposure variables. In conclusion, use of pesticides by Danish farmers is not a likely cause of short-term effects on semen quality and reproductive hormones. 相似文献
40.
S. Caillard C. Lelong F. Pessione B. Moulin for the French PTLD Working Group 《American journal of transplantation》2006,6(11):2735-2742
Post-transplant lymphoproliferative disorders (PTLD) are a rare but serious complication after organ transplantation. A French Registry of PTLD was set up in a nationwide population of kidney transplant recipients. We prospectively enrolled all adult kidney recipients developing PTLD between January 1, 1998, and December 31, 2003. We analyzed the incidence, risk and prognostic factors of PTLD by Kaplan-Meier and Cox analyses. Totally 230 cases of PTLD were referred to the French Registry. Cumulative incidence was 1.18% after 5 years. Older age (per year, AHR = 2.19, CI = 1.22-3.94) and recipient Epstein-Barr virus seronegativity (AHR = 3.01, CI = 1.57-5.08) were associated with an increased risk of PTLD. Patients with PTLD had a reduced survival rate (61% at 5 years). Graft PTLD had the best prognosis with an 81% survival rate after 5 years. Infection with hepatitis C or B virus (HCV or HBV), late-onset PTLD, multiple sites involvement and high Ann Arbor staging were risk factors for patient death. Use of azathioprine was associated with a poorer survival rate. PTLD incidence and risk factors in French recipients are in line with the international or American PTLD series. We highlighted the role of HBV or HCV in patient mortality and described the relevant prognosis factors for patients with post-transplant lymphoproliferations. 相似文献