全文获取类型
收费全文 | 453篇 |
免费 | 25篇 |
专业分类
478篇 |
出版年
2023年 | 10篇 |
2022年 | 9篇 |
2021年 | 22篇 |
2020年 | 12篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 12篇 |
2016年 | 20篇 |
2015年 | 29篇 |
2014年 | 23篇 |
2013年 | 44篇 |
2012年 | 35篇 |
2011年 | 46篇 |
2010年 | 31篇 |
2009年 | 20篇 |
2008年 | 16篇 |
2007年 | 24篇 |
2006年 | 11篇 |
2005年 | 12篇 |
2004年 | 14篇 |
2003年 | 15篇 |
2002年 | 11篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1968年 | 4篇 |
1965年 | 1篇 |
排序方式: 共有478条查询结果,搜索用时 31 毫秒
41.
42.
43.
In the present investigation, a microorganism hydrolyzing carboxymethylcellulose (CMC) was isolated and identified as Bacillus subtilis strain LFS3 by 16S rDNA sequence analysis. The carboxymethylcellulase (CMCase) enzyme produced by the B. subtilis strain LFS3 was purified by (NH?)?SO? precipitation, ion exchange and gel filtration chromatography, with an overall recovery of 15 %. Native-PAGE analysis of purified CMCase revealed the molecular weight of enzyme to be about 185 kDa. The activity profile of CMCase enzyme showed the optimum activity at temperature 60 °C and pH 4.0, respectively. The enzyme activity was induced by Na?, Mg2?, NH??, and EDTA, whereas strongly inhibited by Hg2? and Fe3?. The purified enzyme hydrolyzed CMC, filter paper, and xylan, but not p-nitrophenyl β-D-glucopyranoside and cellulose. Kinetic analysis of purified enzyme showed the K(m) value of 2.2 mg/ml. Thus, acidophilic as well as thermophilic nature makes this cellulase a suitable candidate for current mainstream biomass conversion into fuel and other industrial processes. 相似文献
44.
Cellular heat shock factor 1 positively regulates human immunodeficiency virus-1 gene expression and replication by two distinct pathways 总被引:1,自引:0,他引:1
Human immunodeficiency virus-1 (HIV-1) infection leads to changes in cellular gene expression, which in turn tend to modulate viral gene expression and replication. Cellular heat shock proteins (HSPs) are induced upon heat shock, UV irradiation and microbial or viral infections. We have reported earlier Nef-dependent induction of HSP40 leading to increased HIV-1 gene expression; however, the mechanism of induction remained to be elucidated. As expression of HSPs is regulated by heat shock factors (HSFs), we have now studied the role of HSF1 not only in Nef-dependent HSP40 induction but also in HIV-1 gene expression. Our results show that HSF1 is also induced during HIV-1 infection and it positively regulates HIV-1 gene expression by two distinct pathways. First, along with Nef it activates HSP40 promoter which in turn leads to increased HIV-1 gene expression. Second, HSF1 directly interacts with newly identified HSF1 binding sequence on HIV-1 LTR promoter and induces viral gene expression and replication. Thus, the present work not only identifies a molecular basis for HSF1-mediated enhancement of viral replication but also provides another example of how HIV-1 uses host cell machinery for its successful replication in the host. 相似文献
45.
Santosh Kumar Sharma Shrawan Kumar Deepika Rawat Suman Kumaria Arun Kumar Satyawada Rama Rao 《Biochemical Systematics and Ecology》2011
Selected amplicon data obtained through our earlier study using ISSR and DAMD markers were utilized for determination of diversity within and among the populations of Prosopis cineraria (L.) accessions collected from different districts of Rajasthan (India). A total of 83 bands were generated from eight ISSR and five DAMD primers of which 79 were found to be polymorphic (95.18%). Nei’s gene diversity (h) ranged between 0.185 and 0.301 with overall diversity of 0.316 while Shannon’s information index (I) values recorded between 0.253 and 0.438 with an average value of 0.243. The gene flow value (1.713) and the diversity among populations (0.226) demonstrated higher genetic variation within the population. It is concluded that P. cineraria is accompanied by high genetic diversity within the population and elevated gene flow showing indications of adaptation to callous and fragile dry conditions of arid environment. 相似文献
46.
Shyam Sundar Sharma Md Aminul Islam Anoop Anand Malik Kamlesh Kumar Madan Singh Negi Shashi Bhushan Tripathi 《Physiology and Molecular Biology of Plants》2016,22(2):193-205
Phenotypic variation of important seed traits like seed length, seed breadth, seed thickness, 100 seed weight and seed oil content were recorded in a total of 157 collected accessions of Pongamia. Out of these, fatty acid profiles of 38 accessions selected based on their high and low oil content was analyzed. Fatty acid profile revealed high variability in stearic, oleic and linoleic acid which varied from 0.42 to 10.61 %, 34.34 to 74.58 %, and 7.00 to 31.28 % respectively. Variations in palmitic and linolenic acid were small. Iodine value, saponification number and cetane number (CN) of fatty acid methyl esters (FAME) of seed oil ranges from 186.99 to 201.25, 81.13 to 108.19 and 46.16 to 56.47 respectively. Fatty acid compositions, degree of unsaturation and CN are the important parameters, which are used to determine quality of FAME were used as biodiesel. Some of the Pongamia accessions identified were higher in oil content while some accessions showed higher degree of unsaturation and a few of them had CN values higher than 55. Genetic diversity analysis with six TE-AFLP primers generated a total of 334 bands out of which 174 (52.10 %) were polymorphic. The genetic similarity ranged from 0.11 to 0.47. These findings clearly showed high level of genetic diversity and all economically desirable traits were not present in a single genotype of Pongamia. All these traits could be selected from these CPTs and transfer to a single elite variety through selection and breeding programme and could be utilized for large scale multiplication and plantation to produce high quantity and quality biodiesel in future. 相似文献
47.
48.
Infection with the Lyme disease pathogen suppresses innate immunity in mice with diet‐induced obesity 下载免费PDF全文
Nataliya Zlotnikov Ashkan Javid Mijhgan Ahmed Azad Eshghi Tian Tian Tang Anoop Arya Anil Bansal Fatima Matar Maitry Parikh Rhodaba Ebady Adeline Koh Nupur Gupta Peng Song Yang Zhang Susan Newbigging Gary P. Wormser Ira Schwartz Robert Inman Michael Glogauer Tara J. Moriarty 《Cellular microbiology》2017,19(5)
Obesity is a major global public health concern. Immune responses implicated in obesity also control certain infections. We investigated the effects of high‐fat diet‐induced obesity (DIO) on infection with the Lyme disease bacterium Borrelia burgdorferi in mice. DIO was associated with systemic suppression of neutrophil‐ and macrophage‐based innate immune responses. These included bacterial uptake and cytokine production, and systemic, progressive impairment of bacterial clearance, and increased carditis severity. B. burgdorferi‐infected mice fed normal diet also gained weight at the same rate as uninfected mice fed high‐fat diet, toll‐like receptor 4 deficiency rescued bacterial clearance defects, which greater in female than male mice, and killing of an unrelated bacterium (Escherichia coli) by bone marrow‐derived macrophages from obese, B. burgdorferi‐infected mice was also affected. Importantly, innate immune suppression increased with infection duration and depended on cooperative and synergistic interactions between DIO and B. burgdorferi infection. Thus, obesity and B. burgdorferi infection cooperatively and progressively suppressed innate immunity in mice. 相似文献
49.
50.
Gupta Bharti Kumar Anoop Sridevi Parikipandla 《International journal of peptide research and therapeutics》2021,27(4):2717-2726
International Journal of Peptide Research and Therapeutics - Human papillomavirus (HPV) remains the major cause of cervical cancer, globally. High risk HPV (Hr-HPV) 16 and 18 together account for... 相似文献