全文获取类型
收费全文 | 510篇 |
免费 | 49篇 |
专业分类
559篇 |
出版年
2022年 | 11篇 |
2021年 | 14篇 |
2020年 | 8篇 |
2019年 | 7篇 |
2018年 | 17篇 |
2017年 | 17篇 |
2016年 | 21篇 |
2015年 | 31篇 |
2014年 | 23篇 |
2013年 | 25篇 |
2012年 | 41篇 |
2011年 | 37篇 |
2010年 | 20篇 |
2009年 | 17篇 |
2008年 | 30篇 |
2007年 | 26篇 |
2006年 | 17篇 |
2005年 | 14篇 |
2004年 | 14篇 |
2003年 | 12篇 |
2002年 | 11篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 5篇 |
1997年 | 3篇 |
1995年 | 4篇 |
1993年 | 3篇 |
1992年 | 9篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1970年 | 7篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1967年 | 3篇 |
1966年 | 4篇 |
排序方式: 共有559条查询结果,搜索用时 0 毫秒
101.
102.
103.
The bacterial ArsA ATPase is the catalytic component of an oxyanion pump that is responsible for resistance to arsenicals and antimonials. Homologues of the bacterial ArsA ATPase are widespread in nature. We had earlier identified the mouse homologue (Asna1) that exhibits 27% identity to the bacterial ArsA ATPase. To identify the physiological role of the protein, heterozygous Asna1 knockout mice (Asna1+/-) were generated by homologous recombination. The Asna1+/- mice displayed similar phenotype as the wild-type mice. However, early embryonic lethality was observed in homozygous Asna1 knockout embryos, between E3.5 (E=embryonic day) and E8.5 stage. These findings indicate that Asna1 plays a crucial role during early embryonic development. 相似文献
104.
Samsiddhi Bhattacharjee Julia Ciampa Stephen Chanock Nilanjan Chatterjee 《American journal of human genetics》2010,86(3):331-1189
Many popular methods for exploring gene-gene interactions, including the case-only approach, rely on the key assumption that physically distant loci are in linkage equilibrium in the underlying population. These methods utilize the presence of correlation between unlinked loci in a disease-enriched sample as evidence of interactions among the loci in the etiology of the disease. We use data from the CGEMS case-control genome-wide association study of breast cancer to demonstrate empirically that the case-only and related methods have the potential to create large-scale false positives because of the presence of population stratification (PS) that creates long-range linkage disequilibrium in the genome. We show that the bias can be removed by considering parametric and nonparametric methods that assume gene-gene independence between unlinked loci, not in the entire population, but only conditional on population substructure that can be uncovered based on the principal components of a suitably large panel of PS markers. Applications in the CGEMS study as well as simulated data show that the proposed methods are robust to the presence of population stratification and are yet much more powerful, relative to standard logistic regression methods that are also commonly used as robust alternatives to the case-only type methods. 相似文献
105.
Anindita Chowdhury Selvaraj Kunjiappan Chiranjib Bhattacharjee Balasubramanian Somasundaram Theivendren Panneerselvam 《In vitro cellular & developmental biology. Animal》2017,53(6):483-493
This study aims mainly to provide an insight and understanding of the effect of glucose utilization efficiency of biogenic gold nanoparticles (GNPs) synthesized through the mediation of Marsilea quadrifolia (M. quadrifolia) methanol extract on 3T3-L1 adipocytes. The biosynthesized GNPs were characterized by UV visible spectrophotometry and FTIR. Simultaneously, the nature, stability, and morphological characteristics were analyzed by XRD, TG-DTA, SEM-EDS, HRTEM, and SAED. The results of characterization studies were used to assess the properties of GNPs. The in vitro cytotoxicity screening indicates that 100 μM of biogenic GNPs were displayed 71.23 ± 1.56% of cellular viability in 3T3-L1 adipocyte cells. Subsequently, increased glucose utilization of biosynthesized GNPs based on a dose-dependent manner on 3T3-L1 has also been demonstrated. The effect of GNPs (30 μg) on glucose uptake was higher than that of insulin and metformin. Moreover, the observed results clearly highlight that the biogenic GNPs have higher efficiency of glucose utilization and cellular viability in 3T3-L1 adipocytes with lower toxicity. 相似文献
106.
Binding affinity and in vitro cytotoxicity of harmaline targeting different motifs of nucleic acids: An ultimate drug designing approach 下载免费PDF全文
Paromita Bhattacharjee Tapas Ghosh Sarita Sarkar Prateek Pandya Kakali Bhadra 《Journal of molecular recognition : JMR》2018,31(4)
The work focuses towards interaction of harmaline, with nucleic acids of different motifs by multispectroscopic and calorimetric techniques. Findings of this study suggest that binding constant varied in the order single‐stranded (ss) poly(A) > double‐stranded calf thymus (CT) DNA > double‐stranded poly(G)·poly(C) > clover leaf tRNAPhe. Prominent structural changes of ss poly(A), CT DNA, and poly(G)· poly(C) with concomitant induction of optical activity in the bound achiral alkaloid molecule was observed, while with tRNAPhe, very weak induced circular dichroism perturbation was seen. The interaction was predominantly exothermic, enthalpy driven, and entropy favored with CT DNA and poly(G)·poly(C), while it was entropy driven with poly(A) and tRNAPhe. Intercalated state of harmaline inside poly(A), CT DNA, and poly(G)·poly(C) was shown by viscometry, ferrocyanide quenching, and molecular docking. All these findings unequivocally pointed out preference of harmaline towards ss poly(A) inducing self‐structure formation. Furthermore, harmaline administration caused a significant decrease in proliferation of HeLa and HepG2 cells with GI50 of 28μM and 11.2μM, respectively. Nucleic acid fragmentation, cellular ultramorphological changes, decreased mitochondrial membrane potential, upregulation of p53 and caspase 3, generation of reactive oxygen species, and a significant increase in the G2/M population made HepG2 more prone to apoptosis than are HeLa cells. 相似文献
107.
Biomass production and reproduction of a group of four adult Perionyx excaratus were studied in limited supplies of four experimental diets; cowdung alone and its mixtures with straw, bamboo leaf litter or kitchen waste, in order to select a suitable diet medium for vermiculture. P. excavatus showed maximum rate of biomass increase and reproduction in the mixtures with straw and bamboo leaf litter. In spite of achieving the highest final biomass value. P. excavatus showed the lowest rate of biomass increase and reproduction in the mixture with kitchen waste. Cowdung, a natural food of P. excavatus, was marginally better than the mixture with kitchen waste with regard to the rate of biomass increase and reproduction. 相似文献
108.
109.
Dutta T Sahoo R Sengupta R Ray SS Bhattacharjee A Ghosh S 《Journal of industrial microbiology & biotechnology》2008,35(4):275-282
The enzymatic hydrolysis of cellulose has potential economical and environment-friendly applications. Therefore, discovery
of new extremophilic cellulases is essential to meet the requirements of industry. Penicillium citrinum (MTCC 6489) that was previously isolated from soil in our laboratory, produced alkali tolerant and thermostable cellulases.
Endoglucanase and filter paper activity hydrolase (FPAse) production of P. citrinum were studied using wheat bran substrate in solid state and submerged culture. Zymogram analysis of endoglucanase revealed
the presence of two isoforms differing in molecular weight. One of them was 90 kDa and other one was 38 kDa. Partially purified
endoglucanase showed two different peaks at pH 5.5 and 8.0, respectively, in its pH optima curve. But FPase showed only one
peak (at pH 6.5) in its pH optima curve. Cellulase of P. citrinum is thermostable in nature. The present work reports for the first time, the alkali stable cellulase from alkali tolerant
fungus Penicillium citrinum. Thermostable endoglucanase from P. citrinum may have potential effectiveness as additives to laundry detergents. 相似文献
110.
We are studying variable selection in multiple regression models in which molecular markers and/or gene-expression measurements as well as intensity measurements from protein spectra serve as predictors for the outcome variable (i.e., trait or disease state). Finding genetic biomarkers and searching genetic–epidemiological factors can be formulated as a statistical problem of variable selection, in which, from a large set of candidates, a small number of trait-associated predictors are identified. We illustrate our approach by analyzing the data available for chronic fatigue syndrome (CFS). CFS is a complex disease from several aspects, e.g., it is difficult to diagnose and difficult to quantify. To identify biomarkers we used microarray data and SELDI-TOF-based proteomics data. We also analyzed genetic marker information for a large number of SNPs for an overlapping set of individuals. The objectives of the analyses were to identify markers specific to fatigue that are also possibly exclusive to CFS. The use of such models can be motivated, for example, by the search for new biomarkers for the diagnosis and prognosis of cancer and measures of response to therapy. Generally, for this we use Bayesian hierarchical modeling and Markov Chain Monte Carlo computation. 相似文献