全文获取类型
收费全文 | 241篇 |
免费 | 19篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 3篇 |
2019年 | 15篇 |
2018年 | 15篇 |
2017年 | 11篇 |
2016年 | 14篇 |
2015年 | 7篇 |
2014年 | 20篇 |
2013年 | 22篇 |
2012年 | 13篇 |
2011年 | 18篇 |
2010年 | 12篇 |
2009年 | 12篇 |
2008年 | 8篇 |
2007年 | 10篇 |
2006年 | 11篇 |
2005年 | 14篇 |
2004年 | 10篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 1篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1987年 | 1篇 |
排序方式: 共有260条查询结果,搜索用时 93 毫秒
61.
Mohd. Moshahid Khan Tauheed Ishrat Ajmal Ahmad Md. Nasrul Hoda M. Badruzzaman Khan Gulrana Khuwaja Pallavi Srivastava Syed Shadab Raza Fakhrul Islam Saif Ahmad 《Chemico-biological interactions》2010,183(1):255-263
Restoration of blood flow to an ischemic brain region is associated with generation of reactive oxygen species (ROS) with consequent reperfusion injury. ROS cause lipid peroxidation, protein oxidation, and DNA damage, all of which are deleterious to cells. So diminishing the production of free radicals and scavenging them may be a successful therapeutic strategy for the protection of brain tissue in cerebral stroke. The present study investigated the neuroprotective effect of sesamin (Sn) to reduce brain injury after middle cerebral artery occlusion (MCAO). The middle cerebral artery (MCA) of adult male Wistar rat was occluded for 2 h and reperfused for 22 h. Sesamin is the most abundant lignan in sesame seed oil is a potent antioxidant. Sesamin (30 mg/kg) was given orally twice, 30 min before the onset of ischemia and 12 h after reperfusion. The initial investigations revealed that sesamin reduced the neurological deficits in terms of behavior and reduced the level of thiobarbituric acid reactive species (TBARS), and protein carbonyl (PC) in the different areas of the brain when compared with the MCAO group. A significantly depleted level of glutathione and its dependent enzymes (glutathione peroxidase [GPx] and glutathione reductase [GR]) in MCAO group were protected significantly in MCAO group treated with sesamin. The present study suggests that sesamin may be able to attenuate the ischemic cell death and plays a crucial role as a neuroprotectant in regulating levels of reactive oxygen species in the rat brain. Thus, sesamin may be a potential compound in stroke therapy. 相似文献
62.
63.
Khalid Sadki Hoda Lamsyah Blanca Rueda ELmahfoud Akil Abderrahim Sadak Javier Martin Rajae El Aouad 《遗传学报》2010,37(4):257-264
In order to investigate the influence of functional polymorphisms of macrophage migration inhibitory factor(MIF),Fcg receptors CD16A(FCGR3A) and CD32A (FCGR2A) genes on susceptibility to pulmonary tuberculosis(PTB)in the Moroccan population,we analyzed 123 patients with PTB and 154 healthy controls.The genotyping for MIF-173(G/C)(rs755622),FCGR2A-131H/R(rsl801274)and FCGR3A-158V/F(rs396991) was carried out using TaqMan SNP Genotyping Assay method.We found a statistically significant increase of the MIF-173CC homozygote genotype and MIF-173*C allele frequencies in PTB patients compared with healthy controls (17.07%versus 5.84%,P=0.003;and 35.37%versus 26.30%,P=0.02;respectively).In contrast,no association was observed between CGR2A-131H/R and FCGR3A-158V/F polymorphisms and tuberculosis disease.Our finding suggests that MIF-173*C variant may play an important role in the development of active tuberculosis. 相似文献
64.
Delayed Product Differentiation (DPD) can reduce the manufacturing complexities arising due to the proliferation of products variety. A new optimization model constructs the optimum layout of delayed differentiation assembly lines for a mix of products to be manufactured by the same system and optimizes the position of the differentiation points. This model employs a classification tool (Cladistics) used in biological analysis and modifies it for use in planning DPD assembly lines configurations in order to incorporate the assembly precedence constraints, required production rates of different product variants and existing production capacity of work stations. The optimum layout configuration ensures that the quantities required of different products are produced on the same line; while achieving balance, minimizing duplication of stations and maximizing the overall system utilization. The developed model has been applied to a group of automobile engine accessories normally assembled on different lines. The use of Cladistics to analyze product variants that are candidates for delayed assembly is an original approach for designing the assembly line layout and identifying the best differentiation points. It also helps rationalize the design of product variants and their features to further delay their assembly differentiation and achieve economy of scale without affecting their functionality. 相似文献
65.
Mohammad Ali Faramarzi Mojtaba Tabatabaei Yazdi Hadi Ghostinroudi Mohsen Amini Younes Ghasemi Hoda Jahandar Homeira Arabi 《Annals of microbiology》2006,56(3):253-256
Nostoc muscorum PTCC 1636 was examined for its ability to convert androst-4-en-3,17-dione (AD) and androst-1,4-dien-3,17-dione (ADD) to their 17-hydroxy related derivatives in BG-11 medium. Bioconversion procedures were carried out at 25 °C without shaking. The metabolites obtained were purified using chromatographic methods and characterized as testosterone and 1-dehydrotestosterone on the basis of their spectroscopic features. In both cases, the bioreaction characteristics observed were 17-carbonyl reduction. 相似文献
66.
Hepatic Canalicular Membrane Transport of Bile Salt in C57L/J and AKR/J Mice: Implications for Cholesterol Gallstone Formation 总被引:3,自引:0,他引:3
C57L/J (gallstone-susceptible) and AKR/J (gallstone-resistant) mice have been utilized for quantitative trait loci (QTL) analysis to identify the Lith 1 locus for cholelithiasis. Abcb11 encodes for the liver canalicular membrane bile salt export pump (BSEP), which maps to this QTL and is a candidate gene for Lith 1. We investigated the transmembrane transport of taurocholate in canalicular liver membrane vesicles isolated from these murine strains. Canalicular liver plasma membranes (cLPM) and RNA were isolated from C57L/J and AKR/J mice livers, and were utilized for Northern and Western blot analysis and functional 3H-taurocholate uptake studies. ATP-dependent 3H-taurocholate uptake was significantly higher in AKR/J, compared to C57L/J mice. V
max was 127 vs. 42 pmol TC/mg/s in the murine strains, respectively, while K
m was unchanged. In contrast, gene and protein expression of hepatic Abcb11 was increased three-fold in C57L/J, compared to AKR/J mice. Thus, Abcb11 bile salt transport activity per unit protein was reduced nine-fold in the C57L/J, compared to AKR/J mice. In contrast, canalicular membrane cholesterol:phospholipid content was also significantly higher in the C57L/J mice. We conclude that gallstone-susceptible C57L/J mice demonstrate increased gene and canalicular membrane expression of Abcb11, however, taurocholate transport is functionally diminished. The latter may be due to the increased cholesterol membrane content of the cLPM in C57L/J mice. These findings may be important for the pathogenesis of gallstone formation. 相似文献
67.
El-Enshasy HA Beshay UI El-Diwany AI Omar HM El-Kholy AG El-Najar R 《Acta microbiologica Polonica》2003,52(3):301-313
The production of rifamycins B and SV using glucose as main C-source by Amycolatopsis mediterranei in batch and fed-batch culture was investigated. Fed-batch culture using glucose as mono feeding substrate either in the form of pulse addition, in case of shake flask, or with constant feeding rate, in bioreactor level, proved to be an alternative production system with a significant increase in both volumetric and specific antibiotic production. The maximal concentrations of about 1146 mg/l and 2500 mg/l of rifamycins B and SV, respectively, was obtained in fed-batch culture in bioreactor level under non-oxygen limitation. On the other hand, the rate of rifamycins production was increased from 6.58 to 12.13 mg/l x h for rifamycin B and from 9.47 to 31.83 mg/l x h for rifamycin SV on the bioprocess transfer and improvement from the conventional batch cultivation in shake flask to fed-batch cultivation in stirred tank bioreactor. 相似文献
68.
69.
Available data suggesting the occurrence of "bystander effects" (i.e. damage induction in cells not traversed by radiation) were collected and critically evaluated, in view of the development of low-dose risk models. Although the underlying mechanisms are largely unknown, cellular communication seems to play a key role. In this context, the main features of cellular communication were summarised and a few representative studies on bystander effects were reported and discussed. Three main approaches were identified: (1) conventional irradiation of cell cultures with very low doses of light ions; (2) irradiation of single cells with microbeam probes; (3) treatment with irradiated conditioned medium (ICM), i.e. feeding of unexposed cells with medium taken from irradiated cultures. Indication of different types of bystander damage (e.g. cell killing, gene mutations and modifications in gene expression) has been found in each of the three cases. The interpretations proposed by the investigators were discussed and possible biases introduced by specific experimental conditions were outlined. New arguments and experiments were suggested, with the main purpose of obtaining quantitative information to be included in models of low-dose radiation action. Implications in interpreting low-dose data and modelling low-dose effects at cellular and supra-cellular level, including cancer induction, were analysed. Possible synergism with other low-dose specific phenomena such as adaptive response (AR) (i.e. low-dose induced resistance to subsequent irradiation) was discussed. 相似文献
70.
Whole-genome sequence analysis of Pseudomonas syringae pv. phaseolicola 1448A reveals divergence among pathovars in genes involved in virulence and transposition
下载免费PDF全文
![点击此处可从《Journal of bacteriology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Joardar V Lindeberg M Jackson RW Selengut J Dodson R Brinkac LM Daugherty SC Deboy R Durkin AS Giglio MG Madupu R Nelson WC Rosovitz MJ Sullivan S Crabtree J Creasy T Davidsen T Haft DH Zafar N Zhou L Halpin R Holley T Khouri H Feldblyum T White O Fraser CM Chatterjee AK Cartinhour S Schneider DJ Mansfield J Collmer A Buell CR 《Journal of bacteriology》2005,187(18):6488-6498
Pseudomonas syringae pv. phaseolicola, a gram-negative bacterial plant pathogen, is the causal agent of halo blight of bean. In this study, we report on the genome sequence of P. syringae pv. phaseolicola isolate 1448A, which encodes 5,353 open reading frames (ORFs) on one circular chromosome (5,928,787 bp) and two plasmids (131,950 bp and 51,711 bp). Comparative analyses with a phylogenetically divergent pathovar, P. syringae pv. tomato DC3000, revealed a strong degree of conservation at the gene and genome levels. In total, 4,133 ORFs were identified as putative orthologs in these two pathovars using a reciprocal best-hit method, with 3,941 ORFs present in conserved, syntenic blocks. Although these two pathovars are highly similar at the physiological level, they have distinct host ranges; 1448A causes disease in beans, and DC3000 is pathogenic on tomato and Arabidopsis. Examination of the complement of ORFs encoding virulence, fitness, and survival factors revealed a substantial, but not complete, overlap between these two pathovars. Another distinguishing feature between the two pathovars is their distinctive sets of transposable elements. With access to a fifth complete pseudomonad genome sequence, we were able to identify 3,567 ORFs that likely comprise the core Pseudomonas genome and 365 ORFs that are P. syringae specific. 相似文献