全文获取类型
收费全文 | 38547篇 |
免费 | 1947篇 |
国内免费 | 147篇 |
专业分类
耳鼻咽喉 | 518篇 |
儿科学 | 914篇 |
妇产科学 | 744篇 |
基础医学 | 4891篇 |
口腔科学 | 2203篇 |
临床医学 | 2743篇 |
内科学 | 9929篇 |
皮肤病学 | 939篇 |
神经病学 | 3120篇 |
特种医学 | 797篇 |
外科学 | 5718篇 |
综合类 | 236篇 |
一般理论 | 13篇 |
预防医学 | 2836篇 |
眼科学 | 691篇 |
药学 | 2114篇 |
中国医学 | 135篇 |
肿瘤学 | 2100篇 |
出版年
2024年 | 30篇 |
2023年 | 266篇 |
2022年 | 624篇 |
2021年 | 1402篇 |
2020年 | 741篇 |
2019年 | 1094篇 |
2018年 | 1280篇 |
2017年 | 838篇 |
2016年 | 933篇 |
2015年 | 1064篇 |
2014年 | 1583篇 |
2013年 | 1921篇 |
2012年 | 3155篇 |
2011年 | 3277篇 |
2010年 | 1875篇 |
2009年 | 1569篇 |
2008年 | 2649篇 |
2007年 | 2665篇 |
2006年 | 2592篇 |
2005年 | 2506篇 |
2004年 | 2131篇 |
2003年 | 1922篇 |
2002年 | 1710篇 |
2001年 | 191篇 |
2000年 | 141篇 |
1999年 | 223篇 |
1998年 | 290篇 |
1997年 | 224篇 |
1996年 | 200篇 |
1995年 | 190篇 |
1994年 | 146篇 |
1993年 | 110篇 |
1992年 | 104篇 |
1991年 | 85篇 |
1990年 | 52篇 |
1989年 | 39篇 |
1988年 | 46篇 |
1987年 | 42篇 |
1986年 | 44篇 |
1985年 | 52篇 |
1984年 | 55篇 |
1983年 | 54篇 |
1982年 | 43篇 |
1981年 | 50篇 |
1980年 | 62篇 |
1979年 | 32篇 |
1978年 | 36篇 |
1977年 | 45篇 |
1976年 | 28篇 |
1974年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Formation and specification of ventral neuroblasts is controlled by vnd in Drosophila neurogenesis 总被引:1,自引:0,他引:1 下载免费PDF全文
During Drosophila neural development, neuroblasts delaminate from the neuroectoderm of each hemisegment in a stereotypic orthogonal array of five rows and three columns (ventral, intermediate, and dorsal). Prevailing evidence indicates that the individual neuroblast fate is determined by the domain-specific expression of genes along the dorsoventral and anteroposterior axis. Here, we analyze the role of Vnd, a NK-2 homeodomain protein, expressed initially in the ventral neuroectoderm adjacent to the ventral midline, in the dorsoventral patterning of the neuroectoderm and the neuroblasts. We show that in vnd null mutants most ventral neuroblasts do not form and the few that form do not develop ventral fates, but instead develop intermediate-like fates. Furthermore, we demonstrate that Vnd influences the gene expression patterns in the ventral proneural clusters and neuroectoderm, and that its action in neuroblast formation includes, but is not exclusive to the activation of proneural AS-C genes. Through the use of GAL4/UAS gene-expression system we show that ectopic Vnd expression can promote ventral-like fates in intermediate and dorsal neuroblasts and can suppress certain normal characteristics of the intermediate and dorsal neuroectoderm. Our results are discussed in the context of the current evidence in dorsoventral patterning in the Drosophila neuroectoderm. 相似文献
82.
Dr. Bahman Teimourian M.D. Dr. Etianne Massac Jr. M.D. Dr. Carlos E. Wiegering M.D. 《Aesthetic plastic surgery》1985,9(2):97-100
Suction lipectomy has become an accepted procedure and its full use is still being elucidated. The author herein describes the use of suction lipectomy as an adjunct in refining the results of established surgical procedures on the breast. The authors also explain the use of suction lipectomy in doing suction reduction mammoplasty. The advantages of the use of suction lipectomy as an adjunct to breast surgery and for reduction mammoplasty are explained. 相似文献
83.
Sanchez-Luengos Itsasne Lucas-Jiménez Olaia Ojeda Natalia Peña Javier Gómez-Esteban Juan Carlos Gómez-Beldarrain María Ángeles Vázquez-Picón Raquel Foncea-Beti Nerea Ibarretxe-Bilbao Naroa 《Quality of life research》2022,31(11):3241-3252
Quality of Life Research - This study aimed to determine predictors of health-related quality of life (HRQoL) in Parkinson's disease (PD) and to explore their predictive value before and after... 相似文献
84.
Joana Raquel Raposo dos Santos Carlos Matias Dias Alexandre Chiavegatto Filho 《Health Policy and Technology》2021,10(1):79-86
ObjectiveIndividuals without private health insurance have less access to healthcare, therefore are more prone to experience poor health when compared to those who have. Segmentation is an approach to find homogenous groups of people with the purpose of tailoring services and products. In public policy, segmentation might be used to identify characteristics and needs of specific groups and deliver targeted programs and spare costs. We aim to identify and describe segments within the uninsured population to aid targeted policy actions and improve health.MethodsWe used secondary data collected from a representative, nationwide health survey (n=18,204). For the purpose of our analysis, we included data from individuals who answered “no” to the question: “Do you have private health insurance?” (n=12,134). Variables pertaining information on socio-demographic, health status, access and care were used. A multiple correspondence analysis was performed to find principal components followed by a hierarchical cluster.ResultsWe found three clusters. The first (54.12% of our sample) composed by a group of young, middle aged and professionally active individuals without health problems. The second (36.70%), a cluster of aging individuals composed especially by elderly women, either retired or fulfilling domestic tasks, with a long-term health problem. The last (9.17%) composed by elder people, with long-term health problem and scoring low in mental health related questions.ConclusionOur study found three clusters (profiles of individuals) among the uninsured. Ultimately, our findings aim to support policy makers to deliver customized actions to improve health and provide cost-effective policies. 相似文献
85.
Anderson Madison D. Merkin Sharon Stein Everson-Rose Susan A. Widome Rachel Seeman Teresa Magnani Jared W. Rodriguez Carlos J. Lutsey Pamela L. 《Journal of immigrant and minority health / Center for Minority Public Health》2021,23(4):668-668
Journal of Immigrant and Minority Health - The original version of this article unfortunately contained a typo in co-author name. 相似文献
86.
Camargo Carlos Henrique de Souza da Cunha Maria de Lourdes Ribeiro Caramori Jacqueline Costa Teixeira Mondelli Alessandro Lia Montelli Augusto Cezar Barretti Pasqual 《International urology and nephrology》2021,53(2):381-381
International Urology and Nephrology - In the original publication, article title was incorrectly published. 相似文献
87.
Amadio Eliane Martins Marcos Rodrigo Labat Serra Andrey Jorge dos Santos Solange Almeida Caires Jheniphe Rocha Fernandes Guilherme Henrique Cardosos Leal-Junior Ernesto Cesar Ferrari João Carlos Correa de Tarso Camillo de Carvalho Paulo 《Lasers in medical science》2021,36(7):1427-1435
Lasers in Medical Science - Photobiomodulation therapy (PBMT) has been indicated for enforcement on healing skin wounds. This study evaluated the effects of PBMT on the healing of skin wounds... 相似文献
88.
89.
Fabio Casciani Maxwell T. Trudeau Horacio J. Asbun Chad G. Ball Claudio Bassi Stephen W. Behrman Adam C. Berger Mark P. Bloomston Mark P. Callery John D. Christein Massimo Falconi Carlos Fernandez-del Castillo Mary E. Dillhoff Euan J. Dickson Elijah Dixon William E. Fisher Michael G. House Steven J. Hughes John W. Kunstman 《Surgery》2021,169(4):708-720
BackgroundPancreatoduodenectomies at high risk for clinically relevant pancreatic fistula are uncommon, yet intimidating, situations. In such scenarios, the impact of individual surgeon experience on outcomes is poorly understood.MethodsThe fistula risk score was applied to identify high-risk patients (fistula risk score 7–10) from 7,706 pancreatoduodenectomies performed at 18 international institutions (2003–2020). For each case, surgeon pancreatoduodenectomy career volume and years of practice were linked to intraoperative fistula mitigation strategy adoption and outcomes. Consequently, best operative approaches for clinically relevant pancreatic fistula prevention and best performer profiles were identified through multivariable analysis models.ResultsEight hundred and thirty high-risk pancreatoduodenectomies, performed by 64 surgeons, displayed an overall clinically relevant pancreatic fistula rate of 33.7%. Clinically relevant pancreatic fistula rates decreased with escalating surgeon career pancreatoduodenectomy (–49.7%) and career length (–41.2%; both P < .001), as did transfusion and reoperation rates, postoperative morbidity index, and duration of stay. Great experience (≥400 pancreatoduodenectomies performed or ≥21-year-long career) was a significant predictor of clinically relevant pancreatic fistula prevention (odds ratio 0.52, 95% confidence interval 0.35–0.76) and was more often associated with pancreatojejunostomy reconstruction and prophylactic octreotide omission, which were both independently associated with clinically relevant pancreatic fistula reduction. A risk-adjusted performance analysis also correlated with experience. Moreover, minimizing blood loss (≤400 mL) significantly contributed to clinically relevant pancreatic fistula prevention (odds ratio 0.40, 95% confidence interval 0.22–0.74).ConclusionSurgeon experience is a key contributor to achieve better outcomes after high-risk pancreatoduodenectomy. Surgeons can improve their performance in these challenging situations by employing pancreatojejunostomy reconstruction, omitting prophylactic octreotide, and minimizing blood loss. 相似文献
90.
Gustavo Martinez-Mier Pedro I. Moreno-Ley Luis F. Budar-Fernández Marco T. Méndez-López Carlos A. Allende-Castellanos Luis A. Jiménez-López Daniel A. Barrera-Amoros Edgar Aguilar-Sandoval Maritza De la Paz-Román Ernesto Soto-Miranda Yamilli Rivera-Sanchez Mónica Martínez-Maldonado 《Transplantation proceedings》2021,53(3):1005-1009
ContextThymoglobulin is used effectively as induction agent in kidney transplantation but the optimal dose is not well established.ObjectiveDemonstrate that low-dose thymoglobulin (3 mg/kg) has similar efficacy and safety compared to basiliximab induction in low-risk kidney transplantation under standard maintenance immunosuppressionDesign, Setting, ParticipantsProspective randomized study in kidney transplant patients (12/2016-05/2018). Inclusion criteria: Recipients > 18 years, first living donor transplant. Exclusion criteria: Second and multiorgan transplant, ABO incompatibility, positive cross-match, panel reactive antibodies (PRA) > 30%, positive donor-specific antibody, human immunodeficiency virus, hepatitis B surface antigen, hepatitis C virus positive, white blood cells < 2000 cells/mm3, platelets < 75,000 cells/mm3 and malignancy.InterventionGroup A: basiliximab (20 mg D0 and D4). Group B: thymoglobulin (3 mg/kg total). Maintenance immunosuppression: tacrolimus, mycophenolate mofetil, and steroids.Main Outcome MeasuresBiopsy-proven acute rejection (BPAR), delayed graft function, slow graft function, leukopenia, infections, adverse events, graft loss, estimated glomerular filtration rate, and death within 12 months.Results100 patients (basiliximab, n = 53) (thymoglobulin, n = 47) were included. Donor and recipient characteristics were similar except for longer dialysis (basiliximab), PRA class I (1.2% basiliximab, 4.5% thymoglobulin), HLA match (basiliximab 2.8, thymoglobulin 2.2), and cytomegalovirus status. BPAR rate was basiliximab 3.8% and thymoglobulin 6.4% (P = ns). Delayed graft function (basiliximab 3.8%; thymoglobulin 4.3%), slow graft function, and 12-month leukopenia (basiliximab 11.3%, thymoglobulin 21.3%) were similar between groups (P = ns). There was no difference in infections and adverse events between groups. Patient and graft survival were as follows: basiliximab 98.1% and 92.5%, thymoglobulin 100% and 93.6% (P = ns).ConclusionLow-dose thymoglobulin induction (3 mg/kg) can be used effectively and safely in low-risk kidney transplantation with good results during the first year post-transplant. 相似文献