全文获取类型
收费全文 | 934篇 |
免费 | 74篇 |
国内免费 | 1篇 |
专业分类
儿科学 | 35篇 |
妇产科学 | 31篇 |
基础医学 | 117篇 |
口腔科学 | 3篇 |
临床医学 | 85篇 |
内科学 | 337篇 |
皮肤病学 | 20篇 |
神经病学 | 56篇 |
特种医学 | 34篇 |
外科学 | 120篇 |
综合类 | 12篇 |
一般理论 | 1篇 |
预防医学 | 68篇 |
眼科学 | 1篇 |
药学 | 30篇 |
1篇 | |
肿瘤学 | 58篇 |
出版年
2023年 | 6篇 |
2021年 | 49篇 |
2020年 | 24篇 |
2019年 | 45篇 |
2018年 | 35篇 |
2017年 | 24篇 |
2016年 | 26篇 |
2015年 | 29篇 |
2014年 | 30篇 |
2013年 | 29篇 |
2012年 | 63篇 |
2011年 | 59篇 |
2010年 | 35篇 |
2009年 | 38篇 |
2008年 | 40篇 |
2007年 | 44篇 |
2006年 | 32篇 |
2005年 | 34篇 |
2004年 | 23篇 |
2003年 | 19篇 |
2002年 | 18篇 |
2001年 | 14篇 |
2000年 | 15篇 |
1999年 | 9篇 |
1998年 | 12篇 |
1997年 | 22篇 |
1996年 | 14篇 |
1995年 | 12篇 |
1994年 | 17篇 |
1993年 | 11篇 |
1992年 | 10篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 12篇 |
1988年 | 20篇 |
1987年 | 8篇 |
1986年 | 10篇 |
1985年 | 12篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1977年 | 10篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1972年 | 5篇 |
1970年 | 8篇 |
1968年 | 7篇 |
1967年 | 3篇 |
排序方式: 共有1009条查询结果,搜索用时 281 毫秒
1.
2.
This review summarises present knowledge of the chemistry, immunology, genetics and clinical significance of antibodies in the Lewis and secretor histoblood group systems. Although red cell serology has laid the foundations for these systems, more recent advances have been made by studying Lewis and related glycoconjugates with monoclonal antibodies, determining structures by mass spectrometry and NMR spectroscopy, identifying enzymes and their specificities, and identifying the genes by molecular biology. The expression of Lewis system antigens is dependent on Lewis and secretor loci. Fucosyltransferases coded by genes at these loci compete and interact with each other and with other transferases to determine an individual's Lewis and secretor phenotype. Exocrine epithelial cells, mostly of endodermal origin, synthesise the Lewis antigens which, as plasma glycolipids, are secondarily acquired by cells of the peripheral circulation. Phenotyping red cells is often regarded as a simple way of determining the Lewis and sometimes the secretor status of an individual; however, the red cell phenotype is influenced by many factors and may not necessarily reflect someone's Lewis and secretor genotypes. Two main red cell Lewis groups are usually found, Lewis negative and Lewis positive. In Lewis-negative individuals, the secretor genotype does not affect the Lewis phenotype, but in Lewis-positive individuals, the non-secretor genotype generates the Le(a+b–) phenotype, the secretor genotype causes the Le(a–b+) phenotype, and the partial secretor genotype gives rise to the Le(a+b+) phenotype. 相似文献
3.
Nonacid plasma glycolipids from Lewis-negative individuals of nonsecretor, partial-secretor and secretor phenotypes were prepared and separated by thin-layer chromatography and immunostained with radiolabelled Lewis antibodies. Lewis-positive plasma and intestinal epithelial cell glycolipids from Caucasians representing the four recognized Lewis and secretor combined phenotypes were used as controls. By presenting these purified total glycolipids in a cell-free environment to Lewis antibodies we were able to demonstrate the presence of small amounts of Lewis antigens in Lewis-negative individuals. It is shown that lactotetraosylceramide and extended precursor glycolipids are present in all Le(a–b–) nonsecretors. Lea was detected in 1 of the 3 Le(a–b–) nonsecretor plasmas and in the intestinal sample of the same phenotype. Lactotetraosylceramide was absent but H type 1 and Leb were both present in all group O Le(a–b–) secretors, and extended H type 1 reactive structures were also found in the partial secretor. These results clearly demonstrate that although the Lewis-negative phenotype exists at the serological level, this phenotype is not an 'all-or-nothing' phenomenon at the chemical level. We also show that in the presence of reduced fucosyltransferase activity, increased elongation of the precursor chain occurs, which allows us to postulate that fucosylation of the precursor prevents or at least markedly reduces chain elongation. 相似文献
4.
Robert C Stanton Lisa D Mayer Nancy E Oriol Katharine K Treadway Daniel C Tosteson 《Academic medicine》2007,82(5):516-520
An excellent physician must be aware of the countless issues that affect each patient's health. Many medical education programs expose students to a broad spectrum of disparate knowledge and hope they will integrate all the pieces into a coherent whole. The authors describe an explicit approach to integration used at Harvard Medical School since 2003 that aims to enhance students' learning in medical school and throughout their medical careers: the Mentored Clinical Casebook Project (MCCP). The MCCP is constructed on the premise that such integration does not occur suddenly but, rather, is an unending process. A first-year student is assigned to one clinician and follows one patient for one year. The student is expected to spend as much time with the patient as possible, in both clinical and nonclinical settings, seek help from the clinician, and consult other experts and sources to develop a complete picture of the patient's life. The student must produce a casebook that includes, but is not limited to, the patient's history; basic science, clinical, socioeconomic, and cultural issues; and self-reflection. The MCCP is intended to allow students to develop a deeper and more diverse understanding of what comprises a patient's health care life, to discern the patient as a person and the person as a patient. This educational project has been popular with students since its inception, providing them with a personal framework from which to address the needs of future patients and introducing them to how much they will continue to learn from their patients. 相似文献
5.
Cellular expression and genetic control of ABH antigens in primary sensory neurons of marmoset, baboon and man 总被引:3,自引:0,他引:3
Rosella Mollicone David R. Davies Beryl Evans Anne Marie Dalix Rafael Oriol 《Journal of neuroimmunology》1986,10(3):255-269
ABH antigens have been demonstrated in the posterior root ganglia (PRG) of 3 primate species (marmoset, baboon and man). Their expression corresponded to the ABO phenotype of the individual and was independent of the secretor gene. In marmosets more cells were positive for H (33 +/- 9%) than for A (19 +/- 6%). In baboons A or B antigens were more easily detected (66 +/- 9%) than the H antigens (48 +/- 5%). In humans more than two-thirds of PRG cells were positive for H but only a small proportion of these were positive for A or B. The ABH antigens were found mainly in the small and intermediate-size neurons whose central processes project to lamina II of the spinal cord posterior horn. Unipolar neurons of the Gasserian ganglion, neurons of the mesencephalic nucleus of the trigeminal nerve and of some visceral ganglia have also been shown to express these antigens which are also present in the fibre layer and glomeruli of the olfactory bulbs. 相似文献
6.
Different modulation by histamine of IL-4 and interferon-gamma (IFN-γ) release according to the phenotype of human Th0, Th1 and Th2 clones 下载免费PDF全文
Histamine, an important inflammatory mediator in allergic diseases and asthma, has been reported to have modulator effects on T cells, suggesting that the bronchial microenvironment may regulate the function of resident T cells. We examined the effect of histamine on the release of the Th2-associated cytokines IL-4 and IL-5 and the Th1-associated cytokine IFN-γ by 30 CD4+ T cell clones from peripheral blood or bronchial biopsy of one atopic subject. Based on the IL-4/IFN-γ ratio, the clones were ascribed to the Th2 (ratio >1), Th0 (ratio 0.1 and 1) or Th1 (ratio <0.1) phenotype. Histamine inhibited IFN-γ production by Th1-like cells (P<0.02, Kruskall–Wallis), especially from bronchial biopsy, but had no effect on IL-4 release. Regarding Th0 clones, histamine inhibited IL-4 production (P<0.02) in a dose-dependent manner and slightly inhibited IFN-γ production, but had no effect on Th2-like cells. Histamine had a heterogeneous and insignificant effect on IL-5 production. The H2-receptor antagonist ranitidine completely reversed the inhibition of IL-4 and IFN-γ production, whereas the agonist dimaprit mimicked this effect. In contrast, H1- and H3-receptor agonists and antagonists had no significant effect. These data demonstrate that histamine has different effects on IL-4 and IFN-γ release by T helper cells according to their phenotype via H2-receptors. This study extends the immunomodulatory effects of histamine which may contribute to the perpetuation of airway inflammation in asthma. 相似文献
7.
Two myeloma globulins, IgG1-kappa and IgG1-lambda, from a single patient (Im). I. Purification and immunochemical characterization 总被引:1,自引:1,他引:1 下载免费PDF全文
Electrophoretic analysis of the serum from a patient Im suffering from a multiple myeloma revealed the existence of two abnormal bands. Purification of these two fractions on a DEAE—cellulose column showed that both fractions had the same sedimentation coefficient (7S), belonged to the same class (IgG), and subclass (γl) and bore the same allotype (Gm1). However, the heavy (H) chains of one immunoglobulin were associated with type κ light (L) chains whereas those of the other were associated with type λ L chains.Three individual antigenic determinants were found in these two proteins. One was common to the H chains of both proteins and the other two were each specific to one of the L chains. These results suggest that the myeloma cells of patient (Im) were able to produce at least three polypeptide chains, one H chain and two different types of L chains. 相似文献
8.
The role of size, sequence and haplotype in the stability of FRAXA and FRAXE alleles during transmission 总被引:2,自引:5,他引:2
Murray A; Macpherson JN; Pound MC; Sharrock A; Youings SA; Dennis NR; McKechnie N; Linehan P; Morton NE; Jacobs PA 《Human molecular genetics》1997,6(2):173-184
Factors involved in the stability of trinucleotide repeats during
transmission were studied in 139 families in which a full mutation,
premutation or intermediate allele at either FRAXA or FRAXE was
segregating. The transmission of alleles at FRAXA, FRAXE and four
microsatellite loci were recorded for all individuals. Instability within
the minimal and common ranges (0-40 repeats for FRAXA, 0-30 repeats for
FRAXE) was extremely rare; only one example was observed, an increased in
size at FRAXA from 29 to 39 repeats. Four FRAXA and three FRAXE alleles in
the intermediate range (41-60) repeats for FRAXA, 31-60 for FRAXE) were
unstably transmitted. Instability was more frequent for FRAXA intermediate
alleles that had a tract of pure CGG greater than 37 although instability
only occurred in two of 13 such transmissions: the changes observed were
limited to only one or two repeats. Premutation FRAXA alleles over 100
repeats expanded to a full mutation during female transmission in 100% of
cases, in agreement with other published series. There was no clear
correlation between haplotype and probability of expansion of FRAXA
premutations. Instability at FRAXA or FRAXE was more often observed in
conjunction with a second instability at an independent locus suggesting
genomic instability as a possible mechanism by which at least some FRAXA
and FRAXE mutations arise.
相似文献
9.
Mireia Ruiz-Castilla Bruce Dos Santos Claudia Vizcaíno Jacinto Baena Patricia Guilabert Judith Marin-Corral Joan R. Masclans Oriol Roca Juan P. Barret 《Burns : journal of the International Society for Burn Injuries》2021,47(4):906-913
IntroductionSeveral mechanisms play a role in the development of pneumonia after inhalation injury. Our aim was to analyze whether higher concentrations of inflammatory markers or of biomarkers of epithelial injury are associated with a higher incidence of pneumonia in patients with inhalation injury.Material and methodsSecondary analysis of a single-center prospective observational cohort pilot study, performed over a two-year period (2015–2017) at the Burns Unit of the Plastic and Reconstructive Surgery Department of Vall d’Hebron University Hospital. All patients aged 18 with suspected inhalation injury undergoing admission to the Burns Unit were included. Plasma biomarkers of the lung epithelium (RAGE and SP-D), inflammation markers (IL6, IL8), and IL33, as well as soluble suppression of tumorigenicity-2 (sST2) levels, were measured within the first 24 h of admission.ResultsTwenty-four patients with inhalation injury were included. Eight (33.3%) developed pneumonia after a median of 7 (4–8) days of hospital stay. Patients with pneumonia presented higher plasma concentrations of sST2 (2853 [2356–3351] ng/mL vs 1352 [865–1839] ng/mL; p < 0.001), IL33 (1.95 [1.31–2.59] pg/mL vs 1.26 [1.07–1.45] pg/mL; p = 0.002) and IL8 (325.7 [221.6–430.0] pg/mL vs 174.1 [95.2–253.0] pg/mL; p = 0.017) on day 1 of inclusion. Plasma sST2 concentration in the first 24 h demonstrated excellent diagnostic accuracy for predicting the occurrence of pneumonia in patients with smoke inhalation (AUROC 0.929 [95%CI 0.818–1.000]). A cutoff point of ≥2825 ng/mL for sST2 had a sensitivity of 75% and a specificity of 100%. The risk ratio of pneumonia in patients with sST2 ≥ 2825 ng/mL was 7.14 ([95% CI 1.56–32.61]; p = 0.016).ConclusionsPlasma sST2 in the first 24 h of admission predicts the occurrence of pneumonia in patients with inhalation injury. 相似文献
10.
Sotiris Mastoridis María-Carlota Londoño Ada Kurt Elisavet Kodela Elena Crespo John Mason Oriol Bestard Marc Martínez-Llordella Alberto Sánchez-Fueyo 《American journal of transplantation》2021,21(7):2387-2398
In several murine models of transplantation, the “cross-dressing” of recipient antigen presenting cells (APCs) with intact donor major histocompatibility complex (MHC) derived from allograft-released small extracellular vesicles (sEVs) has been recently described as a key mechanism in eliciting and sustaining alloimmune responses. Investigation of these processes in clinical organ transplantation has, however, been hampered by the lack of sensitivity of conventional instruments and assays. We have employed advanced imaging flow cytometry (iFCM) to explore the kinetics of allograft sEV release and the extent to which donor sEVs might induce cross-dressing following liver and kidney transplantation. We report for the first time that recipient APC cross-dressing can be transiently detected in the circulation shortly after liver, but not kidney, transplantation in association with the release of HLA-bearing allograft-derived sEVs. In liver transplant recipients the majority of circulating cells exhibiting donor HLA are indeed cross-dressed cells and not passenger leukocytes. In keeping with experimental animal data, the downstream functional consequences of the transfer of circulating sEVs harvested from human transplant recipients varies depending on the type of transplant and time posttransplant. sEVs released shortly after liver, but not kidney, transplantation exhibit immunoinhibitory effects that could influence liver allograft immunogenicity. 相似文献