全文获取类型
收费全文 | 11258篇 |
免费 | 738篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 110篇 |
儿科学 | 396篇 |
妇产科学 | 357篇 |
基础医学 | 1526篇 |
口腔科学 | 139篇 |
临床医学 | 1056篇 |
内科学 | 2646篇 |
皮肤病学 | 208篇 |
神经病学 | 1019篇 |
特种医学 | 180篇 |
外科学 | 1178篇 |
综合类 | 92篇 |
一般理论 | 8篇 |
预防医学 | 1114篇 |
眼科学 | 377篇 |
药学 | 775篇 |
中国医学 | 41篇 |
肿瘤学 | 824篇 |
出版年
2024年 | 9篇 |
2023年 | 86篇 |
2022年 | 221篇 |
2021年 | 445篇 |
2020年 | 246篇 |
2019年 | 366篇 |
2018年 | 393篇 |
2017年 | 268篇 |
2016年 | 291篇 |
2015年 | 374篇 |
2014年 | 511篇 |
2013年 | 608篇 |
2012年 | 957篇 |
2011年 | 979篇 |
2010年 | 532篇 |
2009年 | 469篇 |
2008年 | 814篇 |
2007年 | 797篇 |
2006年 | 708篇 |
2005年 | 646篇 |
2004年 | 529篇 |
2003年 | 475篇 |
2002年 | 462篇 |
2001年 | 84篇 |
2000年 | 60篇 |
1999年 | 80篇 |
1998年 | 61篇 |
1997年 | 40篇 |
1996年 | 36篇 |
1995年 | 39篇 |
1994年 | 28篇 |
1993年 | 30篇 |
1992年 | 43篇 |
1991年 | 36篇 |
1990年 | 30篇 |
1989年 | 31篇 |
1988年 | 32篇 |
1987年 | 33篇 |
1986年 | 18篇 |
1985年 | 18篇 |
1984年 | 13篇 |
1983年 | 12篇 |
1982年 | 11篇 |
1981年 | 12篇 |
1978年 | 10篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1973年 | 10篇 |
1972年 | 9篇 |
1970年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
82.
Anna Vassiliou Catherine H. Martin Sheryl T. Homa Jesse Stone Andrew Dawkins Mariya N. Genkova Helen Skyla Dela Roca Sejal Parikh Jinal Patel Tet Yap Aideen P. Killeen 《Andrologia》2021,53(2):e13938
Seminal oxidative stress (OS) is a major contributing factor to male infertility. Semen analysis cannot identify reactive oxygen species (ROS), which can be measured using a chemiluminescence assay. Measurement of redox potential provides a more comprehensive assessment of OS, although the test has yet to be fully validated. This study aimed to validate the MiOXsys analyser for measuring static oxidation–reduction potential (sORP). Results demonstrated that duplicate measurements must be taken, sensors must be batch tested, and sockets should be regularly changed to avoid inconsistency in measurement. Measurement of sORP using MiOXsys exhibited good reproducibility across different operators (p = 0.469), analysers (p = 0.963) and days (p = 0.942). It is not affected by mechanical agitation (p = 0.522) or snap freezing and thawing (p = 0.823). The stability of sORP over time requires further verification, particularly in samples with high initial sORP. Measurement is temperature sensitive between 2 and 37°C, significantly increasing with increasing temperature (p = 0.0004). MiOXsys is a more stable assay for assessing OS than chemiluminescence methods and permits greater flexibility for sample handling. MiOXsys could be implemented to complement semen analysis as part of routine diagnostic testing for male infertility and may be useful in identifying contributing factors to idiopathic infertility. 相似文献
83.
Josefine Jnsson Kristina M. Renault Sonia García-Calzn Alexander Perfilyev Angela C. Estampador Kirsten Nrgaard Mads Vendelbo Lind Allan Vaag Line Hjort Kim F. Michaelsen Emma Malchau Carlsen Paul W. Franks Charlotte Ling 《Diabetes》2021,70(4):854
Maternal obesity may lead to epigenetic alterations in the offspring and might thereby contribute to disease later in life. We investigated whether a lifestyle intervention in pregnant women with obesity is associated with epigenetic variation in cord blood and body composition in the offspring. Genome-wide DNA methylation was analyzed in cord blood from 208 offspring from the Treatment of Obese Pregnant women (TOP)-study, which includes pregnant women with obesity randomized to lifestyle interventions comprised of physical activity with or without dietary advice versus control subjects (standard of care). DNA methylation was altered at 379 sites, annotated to 370 genes, in cord blood from offspring of mothers following a lifestyle intervention versus control subjects (false discovery rate [FDR] <5%) when using the Houseman reference-free method to correct for cell composition, and three of these sites were significant based on Bonferroni correction. These 370 genes are overrepresented in gene ontology terms, including response to fatty acids and adipose tissue development. Offspring of mothers included in a lifestyle intervention were born with more lean mass compared with control subjects. Methylation at 17 sites, annotated to, for example, DISC1, GBX2, HERC2, and HUWE1, partially mediates the effect of the lifestyle intervention on lean mass in the offspring (FDR <5%). Moreover, 22 methylation sites were associated with offspring BMI z scores during the first 3 years of life (P < 0.05). Overall, lifestyle interventions in pregnant women with obesity are associated with epigenetic changes in offspring, potentially influencing the offspring’s lean mass and early growth. 相似文献
84.
Daniela de Queiroz Moura Ramon Rawache Marília Ferreira Gomes Garcia Nathalia Farias Vasconcelos Priscila Santos Gustavo Rego Coelho Thiago Luis da Paz Santos Duílio Reis da Rocha Filho Sonia Leite da Silva Eliana Regia Barbosa de Almeida Paula F.C.B.C. Fernandes João Batista Cerqueira José Huygens Parente Garcia Claudia Maria Costa de Oliveira 《Transplantation proceedings》2021,53(4):1345-1349
Transplantation of any organ has some inherent risk of disease transmission, such as infection and malignancy. The present study aims to describe 2 cases of choriocarcinoma transmission after kidney and liver transplantation originating from the same patient. The donor was a 17-year-old woman who died of cerebral hemorrhage. Both organ recipients died of metastatic choriocarcinoma few months after the transplantation, within days after starting chemotherapy. Retrospective hCG (human chorionic gonadotropin hormone) analysis in donor's blood stored at the time of donation had a result of 9324 mIU/mL. Despite its rarity, clinicians should be aware of the risk of transplant-related choriocarcinoma from female donors in childbearing age. In some cases, hCG dosage should be performed before donation. 相似文献
85.
Cecilia Nakid-Cordero Sylvain Choquet Nicolas Gauthier Noureddine Balegroune Nadine Tarantino Véronique Morel Nadia Arzouk Sonia Burrel Géraldine Rousseau Frédéric Charlotte Martin Larsen Vincent Vieillard Brigitte Autran Véronique Leblond Amélie Guihot for the K-VIROGREF Study Group 《American journal of transplantation》2021,21(8):2846-2863
EBV-positive and EBV-negative posttransplant lymphoproliferative disorders (PTLDs) arise in different immunovirological contexts and might have distinct pathophysiologies. To examine this hypothesis, we conducted a multicentric prospective study with 56 EBV-positive and 39 EBV-negative PTLD patients of the K-VIROGREF cohort, recruited at PTLD diagnosis and before treatment (2013–2019), and compared them to PTLD-free Transplant Controls (TC, n = 21). We measured absolute lymphocyte counts (n = 108), analyzed NK- and T cell phenotypes (n = 49 and 94), and performed EBV-specific functional assays (n = 16 and 42) by multiparameter flow cytometry and ELISpot-IFNγ assays (n = 50). EBV-negative PTLD patients, NK cells overexpressed Tim-3; the 2-year progression-free survival (PFS) was poorer in patients with a CD4 lymphopenia (CD4+<300 cells/mm3, p < .001). EBV-positive PTLD patients presented a profound NK-cell lymphopenia (median = 60 cells/mm3) and a high proportion of NK cells expressing PD-1 (vs. TC, p = .029) and apoptosis markers (vs. TC, p < .001). EBV-specific T cells of EBV-positive PTLD patients circulated in low proportions, showed immune exhaustion (p = .013 vs. TC) and poorly recognized the N-terminal portion of EBNA-3A viral protein. Altogether, this broad comparison of EBV-positive and EBV-negative PTLDs highlight distinct patterns of immunopathological mechanisms between these two diseases and provide new clues for immunotherapeutic strategies and PTLD prognosis. 相似文献
86.
Aránzazu Caballero-Marcos Magdalena Salcedo Roberto Alonso-Fernández Manuel Rodríguez-Perálvarez María Olmedo Javier Graus Morales Valentín Cuervas-Mons Alba Cachero Carmelo Loinaz-Segurola Mercedes Iñarrairaegui Lluís Castells Sonia Pascual Carmen Vinaixa-Aunés Rocío González-Grande Alejandra Otero Santiago Tomé Javier Tejedor-Tejada José María Álamo-Martínez Luisa González-Diéguez Flor Nogueras-Lopez Gerardo Blanco-Fernández Gema Muñoz-Bartolo Francisco Javier Bustamante Emilio Fábrega Mario Romero-Cristóbal Rosa Martin-Mateos Julia Del Rio-Izquierdo Ana Arias-Milla Laura Calatayud Alberto A. Marcacuzco-Quinto Víctor Fernández-Alonso Concepción Gómez-Gavara Jordi Colmenero Patricia Muñoz José A. Pons the Spanish Society of Liver Transplantation 《American journal of transplantation》2021,21(8):2876-2884
The protective capacity and duration of humoral immunity after SARS-CoV-2 infection are not yet understood in solid organ transplant recipients. A prospective multicenter study was performed to evaluate the persistence of anti-nucleocapsid IgG antibodies in liver transplant recipients 6 months after coronavirus disease 2019 (COVID-19) resolution. A total of 71 liver transplant recipients were matched with 71 immunocompetent controls by a propensity score including variables with a well-known prognostic impact in COVID-19. Paired case–control serological data were also available in 62 liver transplant patients and 62 controls at month 3 after COVID-19. Liver transplant recipients showed a lower incidence of anti-nucleocapsid IgG antibodies at 3 months (77.4% vs. 100%, p < .001) and at 6 months (63.4% vs. 90.1%, p < .001). Lower levels of antibodies were also observed in liver transplant patients at 3 (p = .001) and 6 months (p < .001) after COVID-19. In transplant patients, female gender (OR = 13.49, 95% CI: 2.17–83.8), a longer interval since transplantation (OR = 1.19, 95% CI: 1.03–1.36), and therapy with renin–angiotensin–aldosterone system inhibitors (OR = 7.11, 95% CI: 1.47–34.50) were independently associated with persistence of antibodies beyond 6 months after COVID-19. Therefore, as compared with immunocompetent patients, liver transplant recipients show a lower prevalence of anti-SARS-CoV-2 antibodies and more pronounced antibody levels decline. 相似文献
87.
Emilia J. Ling Molly Frean Jody So Maike Tietschert Nancy Song Christian Covington Hassina Bahadurazada Sonia Khurana Luis Garcia Sara J. Singer 《Health services research》2021,56(3):507
ObjectiveThis study sought to identify potential disparities among racial/ethnic groups in patient perceptions of integrated care (PPIC) and to explore how methodological differences may influence measured disparities.Data SourceData from Medicare beneficiaries who completed the 2015 Medicare Current Beneficiary Survey (MCBS) and were enrolled in Part A benefits for an entire year.Study DesignWe used 4‐point measures of eight dimensions of PPIC and assessed differences in dimensions among racial/ethnic groups. To estimate differences, we applied a “rank and replace” method using multiple regression models in three steps, balancing differences in health status among racial groups and adjusting for differences in socioeconomic status. We reran all analyses with additional SES controls and using standard multiple variable regression.Data Collection/Extraction MethodsNot applicable.Principal FindingsWe found several significant differences in perceived integrated care between Black versus White (three of eight measures) and Hispanic versus White (one of eight) Medicare beneficiaries. On average, Black beneficiaries perceived more integrated support for self‐care than did White beneficiaries (mean difference = 0.14, SE = 0.06, P =.02). Black beneficiaries perceived more integrated specialists’ knowledge of past medical history than did White beneficiaries (mean difference = 0.12, SE = 0.06, P =.01). Black and Hispanic beneficiaries also each reported, on average, 0.18 more integrated medication and home health management than did White beneficiaries (P <.01 and P <.01). These findings were robust to sensitivity analyses and model specifications.ConclusionsThere exist some aspects of care for which Black and Hispanic beneficiaries may perceive greater integrated care than non‐Hispanic White beneficiaries. Further studies should test theories explaining why racial/ethnic groups perceive differences in integrated care. 相似文献
88.
Sonia Raskovsky Emilio Rivas Delia Bernik Jorge Medina Diana Jerusalinsky 《Molecular and chemical neuropathology / sponsored by the International Society for Neurochemistry and the World Federation of Neurology and research groups on neurochemistry and cerebrospinal fluid》1990,13(1-2):17-32
The modulation of the binding of muscarinic cholinergic receptor ligands by phosphatidylserine purified from bovine cerebral cortex (BC-PS) was examined in vitro and in vivo. The enrichment of bovine cerebral cortical synaptosomal membranes with BC-PS, using a fusion technique, produced a concentration-dependent decrease in the affinity (increase in K d ) of [3H]quinuclidinyl benzylate (3H-QNB) specific binding to muscarinic acetylcholine receptors (mAChR), without changes in their maximal number (Bmax). Similar results were observed when [3H]oxotremorine (3H-OXO) was used to label a high affinity subpopulation of mAChR. On the other hand, preincubation of BC-PS liposomes with synaptosomal membranes in a nonoptimum fusion condition (at pH 7.4) did not alter the binding properties of both radioligands. Fusion experiments using a pure phosphatidylserine preparation from spinal cord revealed a similar decrement in the affinity of3H-QNB specific binding. Five day’s intraperitoneal (i.p.) administration of 15 mg/kg of BC-PS liposomes in rats increased the maximal number of cerebral cortical binding sites for3H-OXO. Scatchard analysis revealed no changes in the apparent dissociation constant. This modification is selective in relation to the neural structure studied. Thus, BC-PS treatment did not modify3H-OXO binding in the hippocampal formation and cerebellum. In contrast, parallel experiments using the muscarinic antagonist3H-QNB showed no alteration in the binding properties of mAChR. Five day’s i.p. administration of 15 mg/kg/d of phosphatidylcholine from bovine cerebral cortex (BC-PC) liposomes produced quite similar results to those obtained with BC-PS. These results indicate that mAChR are under the modulatory action of phosphatidylserine (PS) and phosphatidylcholine (PC), and suggest that this endogenous phospholipids may play a regulatory role on the mAChR. The possible implications of these findings on the effects of PC or PS treatment in neurological disorders involving a decrease in central cholinergic functions are discussed. 相似文献
89.
The shelter experiences, employment history, income and social service needs utilization were examined among 124 emergency shelter users in Vancouver, British Columbia. Thirty-six (30.5%) reported this as their first experience with living in a shelter; the length of stay in the present shelter ranged from one to 90 days. Reasons for shelter use included: eviction from last place of residence, loss of job, or suffering from health problems rendering one unable to work. The highest unmet service needs were finding affordable housing and finding a job. This combination of scarcity of low-cost housing, health problems, and difficulty in finding employment have led to a situation where emergency shelters have become extended places of residence, a home to many.Sonia Acorn, RN, PhD is an Associate Professor at the School of Nursing, University of British Columbia, Vancouver, Canada.This research was funded by the Mr. and Mrs. P.A. Woodward's Foundation and the Vancouver Foundation. 相似文献