全文获取类型
收费全文 | 30538篇 |
免费 | 1752篇 |
国内免费 | 105篇 |
专业分类
耳鼻咽喉 | 278篇 |
儿科学 | 746篇 |
妇产科学 | 658篇 |
基础医学 | 3800篇 |
口腔科学 | 923篇 |
临床医学 | 3182篇 |
内科学 | 6055篇 |
皮肤病学 | 397篇 |
神经病学 | 2927篇 |
特种医学 | 1210篇 |
外科学 | 3437篇 |
综合类 | 311篇 |
一般理论 | 31篇 |
预防医学 | 3016篇 |
眼科学 | 747篇 |
药学 | 2492篇 |
中国医学 | 43篇 |
肿瘤学 | 2142篇 |
出版年
2023年 | 109篇 |
2022年 | 164篇 |
2021年 | 392篇 |
2020年 | 267篇 |
2019年 | 450篇 |
2018年 | 510篇 |
2017年 | 411篇 |
2016年 | 433篇 |
2015年 | 525篇 |
2014年 | 821篇 |
2013年 | 1360篇 |
2012年 | 1965篇 |
2011年 | 2105篇 |
2010年 | 1157篇 |
2009年 | 1183篇 |
2008年 | 2040篇 |
2007年 | 2267篇 |
2006年 | 2263篇 |
2005年 | 2168篇 |
2004年 | 2141篇 |
2003年 | 2026篇 |
2002年 | 1985篇 |
2001年 | 287篇 |
2000年 | 185篇 |
1999年 | 307篇 |
1998年 | 443篇 |
1997年 | 365篇 |
1996年 | 342篇 |
1995年 | 296篇 |
1994年 | 279篇 |
1993年 | 263篇 |
1992年 | 153篇 |
1991年 | 176篇 |
1990年 | 143篇 |
1989年 | 136篇 |
1988年 | 126篇 |
1987年 | 126篇 |
1986年 | 107篇 |
1985年 | 156篇 |
1984年 | 211篇 |
1983年 | 158篇 |
1982年 | 241篇 |
1981年 | 244篇 |
1980年 | 232篇 |
1979年 | 108篇 |
1978年 | 105篇 |
1977年 | 105篇 |
1976年 | 81篇 |
1975年 | 70篇 |
1974年 | 63篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
Aaron Reuben Erika M. Manczak Laura Y. Cabrera Margarita Alegria Meghan L. Bucher Emily C. Freeman Gary W. Miller Gina M. Solomon Melissa J. Perry 《Environmental health perspectives》2022,130(2)
Background: To date, health-effects research on environmental stressors has rarely focused on behavioral and mental health outcomes. That lack of research is beginning to change. Science and policy experts in the environmental and behavioral health sciences are coming together to explore converging evidence on the relationship—harmful or beneficial—between environmental factors and mental health.Objectives: To organize evidence and catalyze new findings, the National Academy of Sciences, Engineering, and Medicine (NASEM) hosted a workshop 2–3 February 2021 on the interplay of environmental exposures and mental health outcomes.Methods: This commentary provides a nonsystematic, expert-guided conceptual review and interdisciplinary perspective on the convergence of environmental and mental health, drawing from hypotheses, findings, and research gaps presented and discussed at the workshop. Featured is an overview of what is known about the intersection of the environment and mental health, focusing on the effects of neurotoxic pollutants, threats related to climate change, and the importance of health promoting environments, such as urban green spaces.Discussion: We describe what can be gained by bridging environmental and psychological research disciplines and present a synthesis of what is needed to advance interdisciplinary investigations. We also consider the implications of the current evidence for a) foundational knowledge of the etiology of mental health and illness, b) toxicant policy and regulation, c) definitions of climate adaptation and community resilience, d) interventions targeting marginalized communities, and e) the future of research training and funding. We include a call to action for environmental and mental health researchers, focusing on the environmental contributions to mental health to unlock primary prevention strategies at the population level and open equitable paths for preventing mental disorders and achieving optimal mental health for all. https://doi.org/10.1289/EHP9889 相似文献
982.
Fayth L. Miles Michael J. Orlich Andrew Mashchak Paulette D. Chandler Johanna W. Lampe Penelope Duerksen-Hughes Gary E. Fraser 《Nutrients》2022,14(3)
It is unclear how vegetarian dietary patterns influence plasma metabolites involved in biological processes regulating chronic diseases. We sought to identify plasma metabolic profiles distinguishing vegans (avoiding meat, eggs, dairy) from non-vegetarians (consuming ≥28 g/day red meat) of the Adventist Health Study-2 cohort using global metabolomics profiling with ultra-performance liquid chromatography mass spectrometry (UPLC-MS/MS). Differences in abundance of metabolites or biochemical subclasses were analyzed using linear regression models, adjusting for surrogate and confounding variables, with cross-validation to simulate results from an independent sample. Random forest was used as a learning tool for classification, and principal component analysis was used to identify clusters of related metabolites. Differences in covariate-adjusted metabolite abundance were identified in over 60% of metabolites (586/930), after adjustment for false discovery. The vast majority of differentially abundant metabolites or metabolite subclasses showed lower abundance in vegans, including xanthine, histidine, branched fatty acids, acetylated peptides, ceramides, and long-chain acylcarnitines, among others. Many of these metabolite subclasses have roles in insulin dysregulation, cardiometabolic phenotypes, and inflammation. Analysis of metabolic profiles in vegans and non-vegetarians revealed vast differences in these two dietary groups, reflecting differences in consumption of animal and plant products. These metabolites serve as biomarkers of food intake, many with potential pathophysiological consequences for cardiometabolic diseases. 相似文献
983.
Chiao Chang Hung-Hsiang Cheng Gary A. Sevison Joshua R. Hendrickson Zairui Li Imad Agha Jay Mathews Richard A. Soref Greg Sun 《Materials》2022,15(3)
We report an investigation on the photo-response from a GeSn-based photodetector using a tunable laser with a range of incident light power. An exponential increase in photocurrent and an exponential decay of responsivity with increase in incident optical power intensity were observed at higher optical power range. Time-resolved measurement provided evidence that indicated monomolecular and bimolecular recombination mechanisms for the photo-generated carriers for different incident optical power intensities. This investigation establishes the appropriate range of optical power intensity for GeSn-based photodetector operation. 相似文献
984.
Ash Kieran Clift David Dodwell Simon Lord Stavros Petrou Sir Michael Brady Gary S. Collins Julia Hippisley-Cox 《British journal of cancer》2022,126(4):533
Apart from high-risk scenarios such as the presence of highly penetrant genetic mutations, breast screening typically comprises mammography or tomosynthesis strategies defined by age. However, age-based screening ignores the range of breast cancer risks that individual women may possess and is antithetical to the ambitions of personalised early detection. Whilst screening mammography reduces breast cancer mortality, this is at the risk of potentially significant harms including overdiagnosis with overtreatment, and psychological morbidity associated with false positives. In risk-stratified screening, individualised risk assessment may inform screening intensity/interval, starting age, imaging modality used, or even decisions not to screen. However, clear evidence for its benefits and harms needs to be established. In this scoping review, the authors summarise the established and emerging evidence regarding several critical dependencies for successful risk-stratified breast screening: risk prediction model performance, epidemiological studies, retrospective clinical evaluations, health economic evaluations and qualitative research on feasibility and acceptability. Family history, breast density or reproductive factors are not on their own suitable for precisely estimating risk and risk prediction models increasingly incorporate combinations of demographic, clinical, genetic and imaging-related parameters. Clinical evaluations of risk-stratified screening are currently limited. Epidemiological evidence is sparse, and randomised trials only began in recent years.Subject terms: Breast cancer, Cancer epidemiology 相似文献
985.
Gary E. Dunn Anthony M. Paolo Joseph J. Ryan Jay N. van Fleet 《Journal of clinical psychology》1994,50(3):454-457
The present study surveyed the attitudes of psychiatrists and psychologists with regard to the existence of dissociative and multiple personality disorders. Questionnaires were sent to psychiatrists and psychologists in all VA Medical Centers. A total of 1,120 VA psychologists and psychiatrists completed the surveys. More than 97% of respondents indicated that they believed in dissociative disorders, while 80% reported a belief in multiple personality disorder. Belief in multiple personality disorder was related significantly to profession, age, and years of experience. 相似文献
986.
Hani El-Gabalawy Michael Gallatin Rosemay Vazeux Gary Peterman John Wilkins 《Arthritis \u0026amp; Rheumatology》1994,37(6):846-854
Objective. To study the distribution of intercellular adhesion molecule receptor (ICAM-R, or ICAM-3), a novel ligand for the leukointegrin lymphocyte function-associated antigen 1 (LFA-1), in normal and rheumatoid synovial membranes and to compare this with the distribution of ICAM-1, ICAM-2, vascular cell adhesion molecule 1 (VCAM-1), and endothelial leukocyte adhesion molecule 1 (ELAM-1). Methods. We performed immunohistochemical analyses of frozen sections of normal and rheumatoid synovial tissue using monoclonal antibodies to the molecules examined. Results. ICAM-1 staining was detectable on the vascular endothelium and the synovial lining cells of both normal and rheumatoid synovial membranes. A variable proportion of lymphocytes infiltrating rheumatoid tissues expressed ICAM-1. ICAM-2 staining was demonstrable in the vascular endothelium of both normal and inflamed tissues, the latter demonstrating a significantly higher proportion of positive vessels. ELAM-1 staining was not detectable in normal synovial membranes but was seen on the endothelium of a limited number of rheumatoid synovial vessels, usually close to the synovial lining cell layer. VCAM-1 staining was intense in both normal and rheumatoid synovial lining cells, but vascular staining was weak in both. In contrast, ICAM-R staining was not detected in association with any synovial blood vessels, but was widely expressed by lymphocytes and macrophages. Cells of the lining layer did not stain for ICAM-R. Conclusion. Although ICAM-R is a ligand for LFA-1 and shares considerable sequence homology with ICAM-1 and ICAM-2, it does not appear to be expressed by the endothelium of normal or inflamed synovial vessels. Intense expression of ICAM-R by rheumatoid synovial lymphocytes and macrophages suggests that it may play a role in processes requiring cell-cell contact, such as antigen presentation and homotypic aggregation. 相似文献
987.
988.
989.
Holland Jessica F. Khandaker Golam M. Dauvermann Maria R. Morris Derek Zammit Stanley Donohoe Gary 《Social psychiatry and psychiatric epidemiology》2020,55(6):723-733
Social Psychiatry and Psychiatric Epidemiology - Early life adversity (ELA) is a significant risk factor for mental health disorders. One hypothesised mechanism by which this occurs is via an... 相似文献
990.