全文获取类型
收费全文 | 18075篇 |
免费 | 1206篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 284篇 |
儿科学 | 421篇 |
妇产科学 | 257篇 |
基础医学 | 2644篇 |
口腔科学 | 567篇 |
临床医学 | 1626篇 |
内科学 | 3846篇 |
皮肤病学 | 174篇 |
神经病学 | 1456篇 |
特种医学 | 557篇 |
外国民族医学 | 1篇 |
外科学 | 2975篇 |
综合类 | 108篇 |
一般理论 | 10篇 |
预防医学 | 1365篇 |
眼科学 | 848篇 |
药学 | 1000篇 |
中国医学 | 10篇 |
肿瘤学 | 1187篇 |
出版年
2023年 | 163篇 |
2022年 | 85篇 |
2021年 | 377篇 |
2020年 | 267篇 |
2019年 | 368篇 |
2018年 | 525篇 |
2017年 | 408篇 |
2016年 | 518篇 |
2015年 | 449篇 |
2014年 | 577篇 |
2013年 | 855篇 |
2012年 | 1139篇 |
2011年 | 1121篇 |
2010年 | 615篇 |
2009年 | 557篇 |
2008年 | 1062篇 |
2007年 | 1099篇 |
2006年 | 1012篇 |
2005年 | 997篇 |
2004年 | 889篇 |
2003年 | 858篇 |
2002年 | 846篇 |
2001年 | 353篇 |
2000年 | 397篇 |
1999年 | 318篇 |
1998年 | 120篇 |
1997年 | 91篇 |
1996年 | 81篇 |
1995年 | 94篇 |
1994年 | 82篇 |
1993年 | 63篇 |
1992年 | 212篇 |
1991年 | 189篇 |
1990年 | 170篇 |
1989年 | 151篇 |
1988年 | 181篇 |
1987年 | 135篇 |
1986年 | 156篇 |
1985年 | 161篇 |
1984年 | 125篇 |
1983年 | 104篇 |
1982年 | 66篇 |
1981年 | 55篇 |
1980年 | 49篇 |
1979年 | 96篇 |
1978年 | 55篇 |
1974年 | 55篇 |
1973年 | 65篇 |
1972年 | 48篇 |
1971年 | 48篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
Bj?rn Stessel Audrey A. Fiddelers Elbert A. Joosten Daisy M.N. Hoofwijk Hans-Fritz Gramke Wolfgang F.F.A. Buhre 《Medicine》2015,94(39)
Traditionally, major complications and unanticipated admission/readmission rates were used to assess outcome after day surgery. However, in view of the relative absence of major complications the quality of recovery (QOR) should be considered one of the principal endpoints after day surgery. In our study, the level of QOR is defined by a combination of the Global Surgical Recovery (GSR) Index and the Quality of Life (QOL).The aim of this study was to analyze prevalence and predictors of QOR after day surgery on the fourth postoperative day.Elective patients scheduled for day surgery from November 2008 to April 2010 were enrolled in a prospective cohort study. Outcome parameters were measured by using questionnaire packages at 2 time points: 1 week preoperatively and 4 days postoperatively. Primary outcome parameter is the QOR and is defined as good if the GSR index >80% as well as the postoperative QOL is unchanged or improved as compared with baseline. QOR is defined as poor if both the GSR index ≤80% and if the postoperative QOL is decreased as compared with baseline. QOR is defined as intermediate in all other cases. Three logistic regression analyses were performed to determine predictors for poor QOR after day surgery.A total of 1118 patients were included. A good QOR was noted in 17.3% of patients, an intermediate QOR in 34.8%, and a poor QOR in 47.8% 4 days after day surgery. The best predictor for poor QOR after day surgery was type of surgery. Other predictors were younger age, work status, and longer duration of surgery. A history of previous surgery, expected pain (by the patient) and high long-term surgical fear were significant predictors of poor QOR in only 1 of 3 prediction models.The QOR at home 4 days after day surgery was poor in the majority of patients and showed a significant procedure-specific variation. Patients at risk for poor QOR can be identified during the preoperative period based on type of surgery, age, work status, and the duration of the surgery. 相似文献
5.
Ronny Redlich Ilona Schneider Nicole Kerkenberg Nils Opel Jonas Bauhaus Verena Enneking Jonathan Repple Elisabeth J. Leehr Dominik Grotegerd Claas Khler Katharina Frster Katharina Dohm Susanne Meinert Tim Hahn Harald Kugel Kathrin Schwarte Christiane Schettler Katharina Domschke Volker Arolt Walter Heindel Bernhard T. Baune Weiqi Zhang Christa Hohoff Udo Dannlowski 《Human brain mapping》2020,41(3):594-604
Epigenetic alterations of the brain‐derived neurotrophic factor (BDNF) gene have been associated with psychiatric disorders in humans and with differences in amygdala BDNF mRNA levels in rodents. This human study aimed to investigate the relationship between the functional BDNF‐Val66Met polymorphism, its surrounding DNA methylation in BDNF exon IX, amygdala reactivity to emotional faces, and personality traits. Healthy controls (HC, n = 189) underwent functional MRI during an emotional face‐matching task. Harm avoidance, novelty seeking and reward dependence were measured using the Tridimensional Personality Questionnaire (TPQ). Individual BDNF methylation profiles were ascertained and associated with several BDNF single nucleotide polymorphisms surrounding the BDNF‐Val66Met, amygdala reactivity, novelty seeking and harm avoidance. Higher BDNF methylation was associated with higher amygdala reactivity (x = 34, y = 0, z = ?26, t(166) = 3.00, TFCE = 42.39, p(FWE) = .045), whereby the BDNF‐Val66Met genotype per se did not show any significant association with brain function. Furthermore, novelty seeking was negatively associated with BDNF methylation (r = ?.19, p = .015) and amygdala reactivity (r = ?.17, p = .028), while harm avoidance showed a trend for a positive association with BDNF methylation (r = .14, p = .066). The study provides first insights into the relationship among BDNF methylation, BDNF genotype, amygdala reactivity and personality traits in humans, highlighting the multidimensional relations among genetics, epigenetics, and neuronal functions. The present study suggests a possible involvement of epigenetic BDNF modifications in psychiatric disorders and related brain functions, whereby high BDNF methylation might reduce BDNF mRNA expression and upregulate amygdala reactivity. 相似文献
6.
7.
Nicole L. Stout DPT Justin C. Brown PhD Anna L. Schwartz PhD FNP Timothy F. Marshall PhD Anna M. Campbell PhD MBE Larissa Nekhlyudov MD MPH David S. Zucker MD PhD Karen M. Basen-Engquist PhD MPH Grace Campbell PhD MSW RN Jeffrey Meyerhardt MD MPH Andrea L. Cheville MD MSSE Kelley R. Covington MS Jennifer A. Ligibel MD Jonas M. Sokolof DO Kathryn H. Schmitz PhD MPH Catherine M. Alfano PhD 《Cancer》2020,126(12):2750-2758
8.
9.
BMP-2 gene polymorphisms and osteoporosis: the Rotterdam Study. 总被引:7,自引:0,他引:7
Marco Medici Joyce Bj van Meurs Fernando Rivadeneira HongYan Zhao Pascal P Arp Albert Hofman Huibert Ap Pols André G Uitterlinden 《Journal of bone and mineral research》2006,21(6):845-854
After reported associations of variations in the BMP-2 gene with osteoporosis in small populations, we studied the association of the BMP-2 gene polymorphisms Ser37Ala and Arg190Ser with osteoporosis in 6353 men and women from the Rotterdam Study. We did not observe an association of these variants with BMD, bone loss, hip structural analysis parameters, and fracture risk. INTRODUCTION: Bone morphogenetic protein 2 (BMP-2) plays a role in osteoblast differentiation. BMP-2 gene variation has previously been associated with osteoporosis in various small populations, but current evidence remains inconclusive about the exact association with osteoporosis. Therefore, we studied the association of two polymorphisms located in the BMP-2 gene (Ser37Ala and Arg190Ser) and haplotypes defined by these polymorphisms with BMD, rates of bone loss, parameters of hip structural analysis (HSA), and fractures in the Rotterdam Study, a large prospective cohort study of diseases in the elderly. MATERIALS AND METHODS: Databases were searched for polymorphisms and haplotype blocks in the BMP-2 gene region. Allele frequencies for Ser37Ala and Arg190Ser were determined in 60 blacks and 110 Chinese from Coriell panels. Genotype data on Ser37Ala and Arg190Ser were available for 6353 individuals from the Rotterdam Study population. Haplotype alleles defined by Ser37Ala and Arg190Ser were inferred using PHASE software. Genotype and haplotype analyses for BMD (measured at the lumbar spine and femoral neck), bone loss per year (measured at the femoral neck), and HSA were performed using AN(C)OVA. Fractures were analyzed using a Cox proportional-hazards model and logistic regression. All outcomes were adjusted for age, height, and weight. RESULTS: Allele frequencies were 2.5% for Ala37 and 40.2% for Ser190, whereas haplotype allele frequencies were 57.28% (Ser37Arg190), 40.19% (Ser37Ser190), 2.50% (Ala37Arg190), and 0.02% (Ala37Ser190). For BMD, bone loss, HSA outcomes, and (incident) fractures, no differences could be seen between genotype and haplotype groups. Conclusions: In this large population-based cohort of Dutch whites, we conclude that the BMP-2 Ser37Ala and Arg190Ser polymorphisms or haplotypes thereof are not associated with parameters of osteoporosis. 相似文献
10.