全文获取类型
收费全文 | 24140篇 |
免费 | 2780篇 |
国内免费 | 323篇 |
专业分类
耳鼻咽喉 | 170篇 |
儿科学 | 920篇 |
妇产科学 | 217篇 |
基础医学 | 2364篇 |
口腔科学 | 1717篇 |
临床医学 | 1616篇 |
内科学 | 4840篇 |
皮肤病学 | 692篇 |
神经病学 | 1979篇 |
特种医学 | 347篇 |
外国民族医学 | 3篇 |
外科学 | 1739篇 |
综合类 | 1857篇 |
现状与发展 | 6篇 |
预防医学 | 4495篇 |
眼科学 | 556篇 |
药学 | 940篇 |
5篇 | |
中国医学 | 658篇 |
肿瘤学 | 2122篇 |
出版年
2024年 | 87篇 |
2023年 | 541篇 |
2022年 | 952篇 |
2021年 | 1301篇 |
2020年 | 1141篇 |
2019年 | 1092篇 |
2018年 | 1085篇 |
2017年 | 1023篇 |
2016年 | 963篇 |
2015年 | 979篇 |
2014年 | 1425篇 |
2013年 | 1849篇 |
2012年 | 1108篇 |
2011年 | 1326篇 |
2010年 | 1053篇 |
2009年 | 1088篇 |
2008年 | 1115篇 |
2007年 | 1030篇 |
2006年 | 950篇 |
2005年 | 780篇 |
2004年 | 747篇 |
2003年 | 712篇 |
2002年 | 665篇 |
2001年 | 526篇 |
2000年 | 331篇 |
1999年 | 306篇 |
1998年 | 316篇 |
1997年 | 355篇 |
1996年 | 286篇 |
1995年 | 255篇 |
1994年 | 212篇 |
1993年 | 180篇 |
1992年 | 193篇 |
1991年 | 183篇 |
1990年 | 155篇 |
1989年 | 145篇 |
1988年 | 120篇 |
1987年 | 102篇 |
1986年 | 108篇 |
1985年 | 83篇 |
1984年 | 57篇 |
1983年 | 61篇 |
1982年 | 46篇 |
1981年 | 45篇 |
1980年 | 43篇 |
1979年 | 25篇 |
1978年 | 18篇 |
1977年 | 24篇 |
1976年 | 16篇 |
1974年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The objective was to evaluate a postal questionnaire screening procedure for selection of subjects with positive reactions to skin prick tests with common allergens. The project consisted of a screening, with subsequent skin prick test of two selected groups. The setting was the Glostrup Population Studies institute in Copenhagen, Denmark. Participants in the screening included 8000 subjects, aged 15–69 years. The subjects were randomly selected from the population of western Copenhagen County, Denmark. From the 6998 respondents (87.5%), 793 subjects were randomly selected (Random Group), and 788 subjects were chosen on the basis of their answers to the questionnaire (Symptom Group). Both groups were invited to take skin prick tests. Attendance rates were 75.5% (Random Group) and 80.6% (Symptom Group).
The main outcome measures were responses (yes or no) to the specific questions and the subjects' skin reaction (positive or negative). The association between symptoms and skin reactivity, adjusted for the effects of sex and age, was summarized by odds ratios. Symptoms on exposure to allergens were highly associated with positive skin reactivity. In the Symptom Group the percentage of subjects with at least one positive skin reaction was 57.7%, which was twice as much (28.4%) as in the Random Group. The results show that it was possible to select a group with high skin reactivity on the basis of the symptoms reported in the screening. Questions about exposure to allergens were the most appropriate for selection of this group. 相似文献
The main outcome measures were responses (yes or no) to the specific questions and the subjects' skin reaction (positive or negative). The association between symptoms and skin reactivity, adjusted for the effects of sex and age, was summarized by odds ratios. Symptoms on exposure to allergens were highly associated with positive skin reactivity. In the Symptom Group the percentage of subjects with at least one positive skin reaction was 57.7%, which was twice as much (28.4%) as in the Random Group. The results show that it was possible to select a group with high skin reactivity on the basis of the symptoms reported in the screening. Questions about exposure to allergens were the most appropriate for selection of this group. 相似文献
72.
Molecular epidemiological and clinical aspects of hepatitis D virus in a unique triple hepatitis viruses (B,C, D) endemic community in Taiwan 总被引:2,自引:0,他引:2
The molecular epidemiological and clinical aspects of hepatitis D virus (HDV) in a unique HBV, HCV, and HDV triple virus endemic community in southern Taiwan were investigated. A total of 2,909 residents aged 45 or older were screened for hepatitis B surface antigen (HBsAg), anti-HCV antibody, and anti-HDV antibody (specifically for HBsAg-positive carriers). Factors that might be associated with HDV infection, viral nucleic acid detection, and genotyping of HBV, HCV, and HDV were investigated. The prevalence of HBsAg and anti-HCV were 12.6% (366/2,909) and 41.6% (1,227/2,909), respectively. For HBsAg carriers, 15.3% (56/366) were positive for anti-HDV assay. Living in a higher endemic district of HCV infection (odds ratio [OR] = 3.2; 95% confidence interval [CI] = 1.7-6.3), male gender (OR = 1.9; 95% CI = 1.1-3.6) and co-infection with HCV (OR = 1.8; 95% CI = 1.0-3.3) were significantly independent factors associated with HDV infection. The detection rate of HDV RNA among anti-HDV-positive patients was only 12.7% (7/55). The mean HBV titer of triple infection group was significantly lower than in the HBV/HDV co-infection group (2.23 vs 3.05 in log(10), copies/ml, P = 0.046). HCV RNA detection among the triple infection group showed 47.4% (9/19) viremia rate and viral loads of 579,121 IU/ml in median (16,803-1,551,190 IU/ml). The prevalent genotype of HBV was type B (23/25); HCV was 1b (7/9) and HDV was IIa/IIb (4/4). Only the presence of HCV RNA predicted the presence of elevated ALT significantly (OR = 25.0; 95% CI = 3.39-184.6). In conclusion, the geographical aggregation of HDV infection paralleled that of HCV infection in this community. HCV suppressed the replication of HBV among triple vital infection patients. HBV and HDV lapsed into a remission or nonreplicative phase in most cases, and HCV acted as a dominant factor in triple viral-infected individuals. Only the presence of HCV RNA was associated with elevated ALT values, but not HBV or HDV. 相似文献
73.
The amplification of hepatitis B virus (HBV) DNA sequences in sera for molecular epidemiology of HBV is an important application of the polymerase chain reaction (PCR) with regard to HBV. To simplify the PCR for this purpose, the optimal concentrations of SDS and detergents for carrying out the proteinase K digestion and the amplification of DNA by Taq polymerase were evaluated. It was found that by using 1% deoxycholic acid as detergent for the proteinase K step and diluting the digest 10 times before carrying out the PCR, the phenol extraction of DNA became superfluous. The sensitivity of this procedure equalled that of PCR after phenol extraction on comparable amounts of serum. Four pairs of oligonucleotide primers were compared for amplification of HBV DNA sequences in 48 sera previously subtyped with respect to hepatitis B surface antigen (HBsAg), and in eight sera with different genotypes of HBV, representing the subtypes of HBsAg P1 to P8, defined at an international meeting [Couroucé-Pauty et al.: "HBs Antigen Subtypes." Basel: Karger, 1976]. Two primer pairs, selected from conserved regions in the X and S genes of HBV, gave a positive PCR with sera harbouring all the eight different strains of HBV, resulting in DNA fragments consistent with the sizes deduced from genome sequence data. Two other primer pairs were selected in order to discriminate genotypes with regard to differences between d/y and w/r strains.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
74.
Mavale-Manuel S Alexandre F Duarte N Albuquerque O Scheinmann P Poisson-Salomon AS de Blic J 《Allergy》2004,59(4):388-393
BACKGROUND: Few studies have looked at risk factors for asthma in African children. We aimed to identify the risk factors associated with childhood asthma in Maputo (Mozambique). METHODS: This case-control study included 199 age-matched children (100 asthmatic and 99 nonasthmatic) who attended Maputo Central Hospital between January 1999 and July 2000. We collected information concerning their familial history of atopy, birth weight, environment and breast-feeding. Detailed information about morbidity and treatment was obtained for each asthmatic child. RESULTS: The children were aged between 18 months and 8 years; 60% were male. The asthmatic children were hospitalized more frequently than the nonasthmatic children (P < 0.0001). Most of the asthmatic children lived in the urban area of Maputo [odd ratio (OR) = 6.73, CI = 3.1-14.0, P < 0.0001], had a parental history of asthma (OR = 26.8, CI = 10.8-68.2, P < 0.0001) or rhinitis (OR = 4, CI = 1.2-13.3, P = 0.005), had at least parent who smoked and were weaned earlier than the nonasthmatic children (OR = 2.4, CI = 1.3-4.4, P < 0.001). CONCLUSION: Childhood asthma was strongly associated with a family history of asthma and rhinitis, the place of residence, having smokers as parents and early weaning from maternal breast milk. These results highlight the need to reassess the management of asthmatic children in Maputo. 相似文献
75.
A. F. Kalyoncu Z. T. Selçuk Y. Karakoca A. S. Emri L. Çöplü A. A. ahin Y. I. Bari 《Allergy》1994,49(6):485-488
Kalyoncu AF, Selçuk ZT, Karakoca Y, Emri AS, Çöplü L, Şahin AA, Bariş YI. Prevalence of childhood asthma and allergic diseases in Ankara, Turkey.
The first epidemiologic survey of the prevalence of childhood asthma and other allergic disease in Ankara, Turkey, was done in May 1992. A questionnaire on factors influencing the atopic status and allergic symptoms was distributed to parents of 1226 children aged 6-12 years. In this questionnaire, parents were asked to give information about physician-diagnosed asthma and atopic dermatitis (AD), and self-reported wheezing and rhinoconjunctivitis (perennial or seasonal). The overall response rate was 85 % and included 502 boys (48.5%) and 534 girls (51.5%). The lifetime prevalences of asthma, wheezing, rhinoconjunctivitis, and AD were 17.4%, 23.3%, 28%, and 6.1%, respectively, and the reported prevalences for the last 12 months were 8.3%, 11.9%, 15.4%, and 4%, respectively. Asthma and other allergic disease had been recognized in 23.2% of the children during the last year; in half of these, more than one disease was present. Eight percent of the families kept pet animals; 95.4% of children had been breast-fed, of whom 61% for more than 6 months; and at least one person smoked at home in the case of 73.9% of children. Some health insurance was available to 72.8% of the families. Cumulative prevalences of wheezing, rhinoconjunctivitis, and AD were significantly associated with the presence of pets, passive smoking at home, and absence of health insurance. The prevalence of asthma was not affected by any of these factors except atopic family history. In conclusion, asthma and other allergic diseases constitute a major health problem for schoolchildren in Ankara. 相似文献
The first epidemiologic survey of the prevalence of childhood asthma and other allergic disease in Ankara, Turkey, was done in May 1992. A questionnaire on factors influencing the atopic status and allergic symptoms was distributed to parents of 1226 children aged 6-12 years. In this questionnaire, parents were asked to give information about physician-diagnosed asthma and atopic dermatitis (AD), and self-reported wheezing and rhinoconjunctivitis (perennial or seasonal). The overall response rate was 85 % and included 502 boys (48.5%) and 534 girls (51.5%). The lifetime prevalences of asthma, wheezing, rhinoconjunctivitis, and AD were 17.4%, 23.3%, 28%, and 6.1%, respectively, and the reported prevalences for the last 12 months were 8.3%, 11.9%, 15.4%, and 4%, respectively. Asthma and other allergic disease had been recognized in 23.2% of the children during the last year; in half of these, more than one disease was present. Eight percent of the families kept pet animals; 95.4% of children had been breast-fed, of whom 61% for more than 6 months; and at least one person smoked at home in the case of 73.9% of children. Some health insurance was available to 72.8% of the families. Cumulative prevalences of wheezing, rhinoconjunctivitis, and AD were significantly associated with the presence of pets, passive smoking at home, and absence of health insurance. The prevalence of asthma was not affected by any of these factors except atopic family history. In conclusion, asthma and other allergic diseases constitute a major health problem for schoolchildren in Ankara. 相似文献
76.
Dyspnoea in a cross-sectional and a longitudinal study of middle-aged men: The Study of Men Born in 1913 and 1923 总被引:1,自引:0,他引:1
ERIKSSON H.; SVARDSUDD K.; LARSSON B.; OHLSON L.-O.; WELIN L.; TIBBLIN G.; WILHELMSEN L. 《European heart journal》1987,8(7):1015-1023
In a longitudinal population study, 855 men, born in 1913 andinitially examined when 50 years old, were followed for 17 yearswith measurements of dyspnoea and other variables performedat ages 50, 54, and 67 years. In addition a sample of 226 menborn in 1923 was followed from 50 to 57 years of age. At thelatest examination, four different methods for measuring dyspnoeawere used, one based on questionnaire, one on interview, andtwo on visual analogue scales. The estimates from these methodswere highly intercorrelated, and correlated with measures ofcardiopulmonary function as well. The prevalence of dyspnoeagrade 2 (shortness of breath when walking with someone of thesame age on the level) or more, not counting the mildest formof dyspnoea in these populations, was 2.8%, 3.0%, 5.2% and 10.3%at 50, 54, 57 and 67 years of age, respectively. Dyspnoea gradel (shortness of breath when walking quickly on the level oruphill) was less well related to age. A scoring system to differentiatevarious possible causes of dyspnoea was applied. About one thirdof the dyspnoeic men had signs and symptoms of cardiac disease,one quarter had pulmonary disease, and a quarter had a combinationof both causes. The remaining 20% had no signs or symptoms indicatingcardiopulmonary disease but in the majority of the cases otherplausible causes were found. 相似文献
77.
社区卫生服务信息系统之健康档案研究 总被引:22,自引:5,他引:17
建立一套标准、规范、电子化的城市社区家庭个人健康档案模式及可接通互联网络的电脑管理信息系统,为社区工医生提供完整的、系统的居民健康状况数据,是社区医生掌握居民健康状况的基本工具,进行社区诊断的主要依据,是进行社区卫生管理的重要前提,也是我国卫生事业发展必然趋势。 相似文献
78.
Isabel M. A. Brüggenwirth Maureen J. M. Werner René Adam Wojciech G. Polak Vincent Karam Michael A. Heneghan Arianeb Mehrabi Jürgen L. Klempnauer Andreas Paul Darius F. Mirza Johann Pratschke Mauro Salizzoni Daniel Cherqui Michael Allison Olivier Soubrane Steven J. Staffa David Zurakowski Robert J. Porte Vincent E. de Meijer all the other contributing centers the European Liver Intestine Transplant Association 《Transplant international》2021,34(10):1928-1937
High-risk combinations of recipient and graft characteristics are poorly defined for liver retransplantation (reLT) in the current era. We aimed to develop a risk model for survival after reLT using data from the European Liver Transplantation Registry, followed by internal and external validation. From 2006 to 2016, 85 067 liver transplants were recorded, including 5581 reLTs (6.6%). The final model included seven predictors of graft survival: recipient age, model for end-stage liver disease score, indication for reLT, recipient hospitalization, time between primary liver transplantation and reLT, donor age, and cold ischemia time. By assigning points to each variable in proportion to their hazard ratio, a simplified risk score was created ranging 0–10. Low-risk (0–3), medium-risk (4–5), and high-risk (6–10) groups were identified with significantly different 5-year survival rates ranging 56.9% (95% CI 52.8–60.7%), 46.3% (95% CI 41.1–51.4%), and 32.1% (95% CI 23.5–41.0%), respectively (P < 0.001). External validation showed that the expected survival rates were closely aligned with the observed mortality probabilities. The Retransplantation Risk Score identifies high-risk combinations of recipient- and graft-related factors prognostic for long-term graft survival after reLT. This tool may serve as a guidance for clinical decision-making on liver acceptance for reLT. 相似文献
79.
80.