全文获取类型
收费全文 | 2786篇 |
免费 | 274篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 47篇 |
儿科学 | 115篇 |
妇产科学 | 53篇 |
基础医学 | 469篇 |
口腔科学 | 63篇 |
临床医学 | 216篇 |
内科学 | 657篇 |
皮肤病学 | 40篇 |
神经病学 | 165篇 |
特种医学 | 446篇 |
外科学 | 277篇 |
综合类 | 98篇 |
一般理论 | 1篇 |
预防医学 | 189篇 |
眼科学 | 73篇 |
药学 | 83篇 |
1篇 | |
肿瘤学 | 72篇 |
出版年
2023年 | 16篇 |
2021年 | 22篇 |
2020年 | 18篇 |
2019年 | 26篇 |
2018年 | 32篇 |
2017年 | 24篇 |
2016年 | 30篇 |
2015年 | 28篇 |
2014年 | 54篇 |
2013年 | 105篇 |
2012年 | 95篇 |
2011年 | 104篇 |
2010年 | 78篇 |
2009年 | 87篇 |
2008年 | 82篇 |
2007年 | 82篇 |
2006年 | 86篇 |
2005年 | 80篇 |
2004年 | 78篇 |
2003年 | 78篇 |
2002年 | 70篇 |
2001年 | 59篇 |
2000年 | 29篇 |
1999年 | 52篇 |
1998年 | 94篇 |
1997年 | 102篇 |
1996年 | 93篇 |
1995年 | 78篇 |
1994年 | 55篇 |
1993年 | 75篇 |
1992年 | 45篇 |
1991年 | 41篇 |
1990年 | 59篇 |
1989年 | 85篇 |
1988年 | 76篇 |
1987年 | 73篇 |
1986年 | 82篇 |
1985年 | 97篇 |
1984年 | 65篇 |
1983年 | 55篇 |
1982年 | 43篇 |
1981年 | 48篇 |
1980年 | 47篇 |
1979年 | 26篇 |
1978年 | 34篇 |
1977年 | 33篇 |
1976年 | 35篇 |
1975年 | 37篇 |
1972年 | 17篇 |
1971年 | 16篇 |
排序方式: 共有3065条查询结果,搜索用时 15 毫秒
101.
An alternative extrinsic pathway of human blood coagulation 总被引:7,自引:0,他引:7
To study the interrelationships of the major human coagulation pathways, factor X activation in normal and various deficient human plasmas was evaluated when clotting was triggered by dilute rabbit or human thromboplastin. Various dilutions of thromboplastin were added to plasma samples containing 3H-labeled factor X, and the time course of factor X activation was determined. At a 1/250 dilution of rabbit brain thromboplastin the rate of factor X activation in factor VIII or factor IX deficient plasma was only 10% of the activation rate seen for normal or factor XI deficient plasma. Reconstitution of the deficient plasmas with factors VIII or IX, respectively, restored normal factor X activation. Similar results were obtained when various dilutions of human thromboplastin replaced the rabbit thromboplastin. From these experiments, it is inferred that normal activation of factor X in plasma due to dilute thromboplastin requires factors VII, IX and VIII. An alternative extrinsic pathway that involves factors VII, IX, and VIII may be a major physiologic extrinsic pathway, and this pathway may help to explain the clinical observations of bleeding diatheses in patients deficient in factors IX or VIII. 相似文献
102.
R C Allsopp H Vaziri C Patterson S Goldstein E V Younglai A B Futcher C W Greider C B Harley 《Proceedings of the National Academy of Sciences of the United States of America》1992,89(21):10114-10118
When human fibroblasts from different donors are grown in vitro, only a small fraction of the variation in their finite replicative capacity is explained by the chronological age of the donor. Because we had previously shown that telomeres, the terminal guanine-rich sequences of chromosomes, shorten throughout the life-span of cultured cells, we wished to determine whether variation in initial telomere length would account for the unexplained variation in replicative capacity. Analysis of cells from 31 donors (aged 0-93 yr) indicated relatively weak correlations between proliferative ability and donor age (m = -0.2 doubling per yr; r = -0.42; P = 0.02) and between telomeric DNA and donor age (m = -15 base pairs per yr; r = -0.43; P = 0.02). However, there was a striking correlation, valid over the entire age range of the donors, between replicative capacity and initial telomere length (m = 10 doublings per kilobase pair; r = 0.76; P = 0.004), indicating that cell strains with shorter telomeres underwent significantly fewer doublings than those with longer telomeres. These observations suggest that telomere length is a biomarker of somatic cell aging in humans and are consistent with a causal role for telomere loss in this process. We also found that fibroblasts from Hutchinson-Gilford progeria donors had short telomeres, consistent with their reduced division potential in vitro. In contrast, telomeres from sperm DNA did not decrease with age of the donor, suggesting that a mechanism for maintaining telomere length, such as telomerase expression, may be active in germ-line tissue. 相似文献
103.
RD Vaithilingam SH Safii NA Baharuddin LP Karen‐Ng R Saub F Ariffin H Ramli A Sharifuddin MFH Hidayat R Raman YK Chan NA Rani RA Rahim N Shahruddin SC Cheong PM Bartold RB Zain 《Oral diseases》2015,21(1):e62-e69
Periodontal bio‐repositories, which allow banking of clinically validated human data and biological samples, provide an opportunity to derive biomarkers for periodontal diagnosis, prognosis and therapeutic activities which are expected to improve patient management. This article presents the establishing of the Malaysian Periodontal Database and Biobank System (MPDBS) which was initiated in 2011 with the aim to facilitate periodontal research. Partnerships were established with collaborating centres. Policies on specimen access, authorship and acknowledgement policies were agreed upon by all participating centres before the initiation of the periodontal biobank. Ethical approval for the collection of samples and data were obtained from institutional ethics review boards. A broad‐based approach for informed consent was used, which covered areas related to quality of life impacts, genetics and molecular aspects of periodontal disease. Sample collection and processing was performed using a standardized protocol. Biobanking resources such as equipment and freezers were shared with the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS). In the development of the MPDBS, challenges that were previously faced by the MOCDTBS were considered. Future challenges in terms of ethical and legal issues will be faced when international collaborations necessitate the transportation of specimens across borders. 相似文献
104.
105.
Mark L. Eberhard Ernesto Ruiz-Tiben Donald R. Hopkins Corey Farrell Fernand Toe Adam Weiss P. Craig Withers Jr. M. Harley Jenks Elizabeth A. Thiele James A. Cotton Zahra Hance Nancy Holroyd Vitaliano A. Cama Mahamat Ali Tahir Tchonfienet Mounda 《The American journal of tropical medicine and hygiene》2014,90(1):61-70
Dracunculiasis was rediscovered in Chad in 2010 after an apparent absence of 10 years. In April 2012 active village-based surveillance was initiated to determine where, when, and how transmission of the disease was occurring, and to implement interventions to interrupt it. The current epidemiologic pattern of the disease in Chad is unlike that seen previously in Chad or other endemic countries, i.e., no clustering of cases by village or association with a common water source, the average number of worms per person was small, and a large number of dogs were found to be infected. Molecular sequencing suggests these infections were all caused by Dracunculus medinensis. It appears that the infection in dogs is serving as the major driving force sustaining transmission in Chad, that an aberrant life cycle involving a paratenic host common to people and dogs is occurring, and that the cases in humans are sporadic and incidental. 相似文献
106.
Jacob CO Eisenstein M Dinauer MC Ming W Liu Q John S Quismorio FP Reiff A Myones BL Kaufman KM McCurdy D Harley JB Silverman E Kimberly RP Vyse TJ Gaffney PM Moser KL Klein-Gitelman M Wagner-Weiner L Langefeld CD Armstrong DL Zidovetzki R 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(2):E59-E67
Systemic lupus erythematosus (SLE), the prototypic systemic autoimmune disease, is a debilitating multisystem autoimmune disorder characterized by chronic inflammation and extensive immune dysregulation in multiple organ systems, resulting in significant morbidity and mortality. Here, we present a multidisciplinary approach resulting in the identification of neutrophil cytosolic factor 2 (NCF2) as an important risk factor for SLE and the detailed characterization of its causal variant. We show that NCF2 is strongly associated with increased SLE risk in two independent populations: childhood-onset SLE and adult-onset SLE. The association between NCF2 and SLE can be attributed to a single nonsynonymous coding mutation in exon 12, the effect of which is the substitution of histidine-389 with glutamine (H389Q) in the PB1 domain of the NCF2 protein, with glutamine being the risk allele. Computational modeling suggests that the NCF2 H389Q mutation reduces the binding efficiency of NCF2 with the guanine nucleotide exchange factor Vav1. The model predicts that NCF2/H389 residue interacts with Vav1 residues E509, N510, E556, and G559 in the ZF domain of Vav1. Furthermore, replacing H389 with Q results in 1.5 kcal/mol weaker binding. To examine the effect of the NCF2 H389Q mutation on NADPH oxidase function, site-specific mutations at the 389 position in NCF2 were tested. Results show that an H389Q mutation causes a twofold decrease in reactive oxygen species production induced by the activation of the Vav-dependent Fcγ receptor-elicited NADPH oxidase activity. Our study completes the chain of evidence from genetic association to specific molecular function. 相似文献
107.
Borges KS Castro-Gamero AM Moreno DA da Silva Silveira V Brassesco MS de Paula Queiroz RG de Oliveira HF Carlotti CG Scrideli CA Tone LG 《Journal of cancer research and clinical oncology》2012,138(3):405-414
Background
Glioblastoma remains one of the most devastating human malignancies, and despite therapeutic advances, there are no drugs that significantly improve the patient survival. Altered expression of the Aurora kinases was found in different malignancies, and their inhibition has been studied in cancer therapy. In this study, we analyzed the expression of Aurora A and Aurora B in glioblastoma samples and also analyzed whether the effects of Aurora kinase inhibition were associated with temozolomide or not on cell lines and primary cultures of glioblastoma. 相似文献108.
109.
110.
Benjamin J. Dixon Michael J. Daly Harley Chan Allan D. Vescan Ian J. Witterick Jonathan C. Irish 《Surgical endoscopy》2013,27(2):454-461