全文获取类型
收费全文 | 291篇 |
免费 | 32篇 |
专业分类
323篇 |
出版年
2021年 | 3篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 8篇 |
2014年 | 8篇 |
2013年 | 8篇 |
2012年 | 15篇 |
2011年 | 19篇 |
2010年 | 7篇 |
2009年 | 9篇 |
2008年 | 18篇 |
2007年 | 16篇 |
2006年 | 15篇 |
2005年 | 11篇 |
2004年 | 8篇 |
2003年 | 13篇 |
2002年 | 8篇 |
2001年 | 14篇 |
2000年 | 12篇 |
1999年 | 14篇 |
1998年 | 9篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1990年 | 4篇 |
1989年 | 13篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1961年 | 1篇 |
1950年 | 1篇 |
1925年 | 1篇 |
1915年 | 1篇 |
排序方式: 共有323条查询结果,搜索用时 15 毫秒
81.
Angelina DR Felix Mami Takahashi Rie Katsumata-Tsuboi Ryo Satoh Teoh Soon Hui 《Bioscience, biotechnology, and biochemistry》2017,81(11):2209-2211
Rice powder extract (RPE) from black and brown rice (Oryza sativa L. indica) improves hepatic lipid accumulation in obese and diabetic model mice via peroxisomal fatty acid oxidation. RPE showed PPARα agonistic activity which did not differ between black and brown RPE despite a higher anthocyanin content in black RPE. 相似文献
82.
83.
The putative new interleukin (IL)-1 family member IL-1F8 (IL-1eta, IL-1H2) has been shown recently to activate mitogen activated protein kinases (MAPKs), extracellular signal-regulated protein kinase (ERK1/2) and c-Jun N-terminal kinase (JNK), and nuclear factor-kappa B (NFkappa B) via a mechanism that requires IL-1Rrp2 expression in cell lines. The aim of this study was to test the hypothesis that IL-1F8 contributes to brain inflammation and injury, by studying its expression and actions in the different cell types of the mouse brain in culture. Messenger RNA for IL-1F8 was detected in neurons and glia (microglial cells, oligodendrocytes progenitor cells and to a lesser extent astrocytes) by RT-PCR. Bacterial lipopolysaccharide (LPS) had no effect on IL-1F8 mRNA levels in mixed glial cultures. Recombinant mouse IL-1beta induced strong activation of ERK1/2, p38, JNK and NFkappa B, and significant release of IL-6 and PGE2, which was blocked by IL-1ra. In contrast, recombinant mouse IL-1F8 did not influence any of these parameters. These results demonstrate that CNS cells may be a source of IL-1F8, but the failure of LPS to modulate IL-1F8 mRNA expression, and of recombinant IL-1F8 to induce any of the classical IL-1 responses, suggest that this cytokine has restricted activities in the brain, or that it may act via alternative pathway(s). 相似文献
84.
Von Wallbrunn C Luftmann H Bergander K Meinhardt F 《The Journal of General and Applied Microbiology》2001,47(1):33-38
By the application of a bioassay based on cresson seedlings, two phytotoxic compounds were isolated by thin-layer chromatography from the culture fluid of a Calonectria morganii isolate. The structure of both compounds was elucidated by ESI/MS and NMR spectroscopy. According to the Chemical Abstracts database, they were identified as chaetoglobosin A and 19-O-acetylchaetoglobosin A, mycotoxins originally described for Chaetomium globosum. 相似文献
85.
86.
Microbial linear plasmids 总被引:6,自引:0,他引:6
While plasmids were originally considered to be generally circular until almost two decades ago, linear elements were reported to exist as well. They are now known to be common genetic elements in both, pro- and eukaryotes. Two
types of linear plasmids exist, the so-called hairpin plasmids with covalently closed ends and those with proteins bound to
their 5′ termini. Hairpin plasmids are common in human-pathogenic Borrelia spirochetes, in which they are instrumental in escape from the immunological response; cryptic hairpin elements are present
in mitochondria of the plant pathogenic fungus Rhizoctonia solani. Plasmids with 5′ attached proteins constitute the largest group. In actinomycetous bacteria they are conjugative and usually
confer advantageous phenotypes, e.g. formation of antibiotics, degradation of xenobiotics, heavy-metal resistance and growth
on hydrogen as the sole energy source. In contrast, the majority of linear plasmids from eukaryotes are cryptic, with only
a few exceptions. In some yeasts a killer phenotype may be associated, the most thoroughly investigated elements being those
from Kluyveromyces lactis killer strains. In Neurospora spp. and in Podospora anserina, senescence and longevity respectively are correlated with linear plasmids. This review focuses on the biology of linear
plasmids, their environmental significance and their use as tools in molecular and applied microbiology.
Received: 15 November 1996 / Received revision: 23 December 1996 / Accepted: 30 December 1996 相似文献
87.
88.
Lambert A. Motilal Dapeng Zhang Sue Mischke Lyndel W. Meinhardt Pathmanathan Umaharan 《Tree Genetics & Genomes》2013,9(6):1395-1411
Cacao (Theobroma cacao L.), the tree from which cocoa butter and chocolate is derived, is conserved in field genebanks. The largest of these ex situ collections in the public domain is the International Cocoa Genebank, Trinidad (ICG,T). Reduction of genetic redundancy is essential to improve the accuracy and efficiency of genebank management. This study examined the pedigree and genetic diversity in a subset of 387 accessions in this collection. Sibship reconstruction of this subset revealed 56 full-sib families nested within 189 half-sib families. Sixteen centers of interconnectivity were identified, which suggested a high level of genetic redundancy in the collection. Generally, consistent phylogenetic trees were obtained using different genetic distance measures. However, a principal coordinate analysis of the D est differentiation measure elicited the best representation of accession group clustering, and we recommend this approach when probing fine-scale genetic differentiation among cacao accessions. The composite genetic diversity of 414 cacao accessions was contained in a core set of 59 unique accessions. These results have significant implications in the conservation of genetic resources of the ICG,T and other cacao genebanks. The approach developed in this study is recommended as a strategy to curators in guiding conservation management practices of cacao and other similar ex situ genebanks. 相似文献
89.
90.
Killer toxins from Kluyveromyces lactis (zymocin) and Pichia acaciae (PaT) were found to disable translation in target cells by virtue of anticodon nuclease (ACNase) activities on tRNAGlu and tRNAGln, respectively. Surprisingly, however, ACNase exposure does not only impair translation, but also affects genome integrity
and concomitantly DNA damage occurs. Previously, it was shown that homologous recombination protects cells from ACNase toxicity.
Here, we have analyzed whether other DNA repair pathways are functional in conferring ACNase resistance as well. In addition
to HR, base excision repair (BER) and postreplication repair (PRR) promote clear resistance to either, PaT and zymocin. Comparative
toxin sensitivity analysis of BER mutants revealed that its ACNase protective function is due to the endonucleases acting
on apurinic (AP) sites, whereas none of the known DNA glycosylases is involved. Because PaT and zymocin require the presence
of the ELP3/TRM9-dependent wobble uridine modification 5-methoxy-carbonyl-methyl (mcm5) for tRNA cleavage, we analyzed toxin response in DNA repair mutants additionally lacking such tRNA modifications. ACNase
resistance caused by elp3 or trm9 mutations was found to rescue hypersensitivity of DNA repair defects, consistent with DNA damage to occur as a consequence
of tRNA cleavage. The obtained genetic evidence promises to reveal new aspects into the mechanism linking translational fidelity
and genome surveillance. 相似文献