全文获取类型
收费全文 | 387篇 |
免费 | 20篇 |
国内免费 | 1篇 |
专业分类
儿科学 | 40篇 |
妇产科学 | 8篇 |
基础医学 | 83篇 |
口腔科学 | 8篇 |
临床医学 | 40篇 |
内科学 | 69篇 |
皮肤病学 | 11篇 |
神经病学 | 7篇 |
特种医学 | 51篇 |
外科学 | 21篇 |
综合类 | 4篇 |
预防医学 | 29篇 |
眼科学 | 1篇 |
药学 | 24篇 |
肿瘤学 | 12篇 |
出版年
2021年 | 7篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 8篇 |
2013年 | 16篇 |
2012年 | 16篇 |
2011年 | 9篇 |
2010年 | 11篇 |
2009年 | 8篇 |
2008年 | 5篇 |
2007年 | 13篇 |
2006年 | 10篇 |
2005年 | 18篇 |
2004年 | 7篇 |
2003年 | 16篇 |
2002年 | 4篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 11篇 |
1997年 | 10篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1993年 | 10篇 |
1992年 | 7篇 |
1989年 | 10篇 |
1988年 | 10篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 9篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1975年 | 8篇 |
1972年 | 6篇 |
1969年 | 6篇 |
1966年 | 4篇 |
1965年 | 3篇 |
1940年 | 2篇 |
1939年 | 3篇 |
1936年 | 2篇 |
排序方式: 共有408条查询结果,搜索用时 0 毫秒
41.
Echicetin: a snake venom protein that inhibits binding of von Willebrand factor and alboaggregins to platelet glycoprotein Ib 总被引:8,自引:4,他引:8
Echicetin, a new protein isolated from Echis carinatus venom by reverse phase and ion exchange chromatography specifically inhibited agglutination of fixed platelets induced by several platelet glycoprotein Ib (GPIb) agonists, such as bovine von Willebrand factor (vWF), alboaggregins, and human vWF in the presence of botrocetin. Unlike alboaggregins, echicetin bound to GPIb but did not induce agglutination of washed or fixed platelets. In contrast to disintegrins, it did not block adenosine 5'-diphosphate (ADP)-induced platelet aggregation in the presence of fibrinogen. The apparent molecular weight of echicetin measured on sodium dodecyl sulfate (SDS) gel electrophoresis was 26 Kd under nonreducing conditions. On reduction, echicetin showed 16 and 14-Kd subunits suggesting that the molecule is a dimer. Reduced echicetin retained its binding activity and its inhibitory effect on the agglutination of fixed platelets induced by bovine vWF. 125I-echicetin bound to fixed platelets with high affinity (kd = 30 +/- 1.8 nmol/L) at 45,000 +/- 2,400 binding sites per platelet. The binding was selectively inhibited by a monoclonal antibody to the 45-Kd N-terminal domain of platelet GPIb, but not by monoclonal antibodies to other regions on GPIb. Binding of 125I-bovine vWF to fixed platelets was strongly inhibited by echicetin. In contrast, bovine vWF showed a much weaker inhibitory activity on binding of 125I-echicetin to platelets. The half life of echicetin in blood was approximately 170 minutes with no detectable degradation. Echicetin significantly prolonged the bleeding time of mice, suggesting that it may inhibit vWF binding to GPIb in vivo as well as in vitro. 相似文献
42.
Effect of surfaces on fluid-phase prekallikrein activation 总被引:2,自引:0,他引:2
The activation of prekallikrein by factor XII fragments (XIIf), during incubation in plastic tubes was previously noted to be increased by high molecular weight (HMW) kininogen as well as other plasma proteins. In this report, we investigated the mechanism responsible for this increase. Although we confirmed that HMW kininogen, bovine serum albumin, fibrinogen, cold insoluble globulin, and mixed phospholipids apparently increased prekallikrein activation, we found that the product of prekallikrein activation (kallikrein) lost substantial activity in less than 0.5 min after exposure to a variety of fresh surfaces. This loss was partially prevented by the presence of various proteins and phospholipids. Similar protection against inactivation of XIIf, the enzyme in this reaction, was also found. In contrast, no loss of the substrate, prekallikrein, was observed during incubation. The loss of kallikrein activity was found to be proportional to the surface area of the incubation vessel as well as the concentration of kallikrein. Further loss of kallikrein activity could also be prevented by pretreating the vessel with kallikrein. We therefore conclude that various substances apparently affect prekallikrein activation in a purified system by preventing the enzyme and product in the reaction mixture from losing activity due to adsorption to a surface. 相似文献
43.
Snyder DS; Negrin RS; O'Donnell MR; Chao NJ; Amylon MD; Long GD; Nademanee AP; Stein AS; Parker PM; Smith EP 《Blood》1994,84(5):1672-1679
Ninety-four consecutive patients with chronic myelogenous leukemia in first clinical chronic phase, median age of 34.0 years (range, 6.8 to 52.4 years), with a histocompatible sibling donor, were treated with fractionated total body irradiation (1,320 cGy) and high-dose etoposide (60 mg/kg) followed by allogeneic bone marrow transplantation (BMT). The median time from diagnosis to BMT was 7.0 months (range, 2.3 to 72.0 months). Sixty patients were treated before BMT with hydroxyurea alone, four patients with busulfan alone, one patient with interferon alone, and the other 29 patients were treated with various combinations of these drugs. Cumulative probabilities of overall survival, event- free survival, and relapse at 5 years were 73%, 64%, and 14%, respectively. The median follow-up time for surviving patients was 38 months, ranging from 12 to 88 months. By stepwise Cox regression analysis, significant prognostic variables were age at transplant, acute graft-versus-host disease > or = grade II, cytomegalovirus- associated interstitial pneumonitis, and years from diagnosis to BMT. 相似文献
44.
Brenda Eskenazi Robert B. Gunier Stephen Rauch Katherine Kogut Emily R. Perito Xenia Mendez Charles Limbach Nina Holland Asa Bradman Kim G. Harley Paul J. Mills Ana M. Mora 《Environmental health perspectives》2023,131(3)
Background: The prevalence of liver disorders and metabolic syndrome has increased among youth. Glyphosate, the most widely used herbicide worldwide, could contribute to the development of these conditions.Objective: We aimed to assess whether lifetime exposure to glyphosate and its degradation product, aminomethylphosphonic acid (AMPA), is associated with elevated liver transaminases and metabolic syndrome among young adults.Methods: We conducted a prospective cohort study ( mother–child dyads) and a nested case–control study ( cases with elevated liver transaminases and 91 controls) using data from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS). We measured glyphosate and AMPA concentrations in urine samples collected during pregnancy and at child ages 5, 14, and 18 y from cases and controls. We calculated glyphosate residue concentrations: []. We estimated the amount of agricultural-use glyphosate applied within a radius of every residence from pregnancy to age 5 y for the full cohort using California Pesticide Use Reporting data. We assessed liver transaminases and metabolic syndrome at 18 y of age.Results: Urinary AMPA at age 5 y was associated with elevated transaminases [relative risk (RR) per , 95% confidence interval (CI): 1.06, 1.53] and metabolic syndrome (, 95% CI: 1.38, 3.11). Urinary AMPA and glyphosate residues at age 14 y were associated with metabolic syndrome [ (95% CI: 1.10, 2.93) and (95% CI: 1.03, 3.42), respectively]. Overall, a 2-fold increase in urinary AMPA during childhood was associated with a 14% and a 55% increased risk of elevated liver transaminases and metabolic syndrome, respectively. Living near agricultural glyphosate applications during early childhood (birth to 5 y of age) was also associated with metabolic syndrome at age 18 y in the case–control group (, 95% CI: 1.16, 2.02).Discussion: Childhood exposure to glyphosate and AMPA may increase risk of liver and cardiometabolic disorders in early adulthood, which could lead to more serious diseases later in life. https://doi.org/10.1289/ EHP11721相似文献
45.
46.
47.
48.
N N Kogut G I Razorenov G A Poddubski? E N Antipenko 《Vestnik Rossi?sko? akademii meditsinskikh nauk / Rossi?skaia akademiia meditsinskikh nauk》1992,(3):51-54
Status metry was used to determine the portion of congenital developmental abnormalities (CDA) of obscure etiology (probably of mutation origin) among the total number of CDA in 3 cities of the Ukraine. The contribution of CDA determined by new mutations correlates with the reported data and corresponds with the level of atmospheric air pollution in the cities under study. Status metry made it also possible to define the tendencies and magnitude of the influence of factors involved in CDA formation. The conclusion is made about adequacy of the use of status metry for indirect estimation of the rate of the mutation process and its modification under the effect of environmental pollution. 相似文献
49.
After a review of the pertinent literature the effect is described of gluten-dependent coeliac disease on the condition of the oral cavity and teeth in children. Attention is called to the condition of the parodontium on the occurrence of developmental abnormalities of hard dental tissuses and caries intensity. 相似文献
50.