全文获取类型
收费全文 | 282篇 |
免费 | 19篇 |
出版年
2022年 | 1篇 |
2021年 | 4篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 6篇 |
2014年 | 16篇 |
2013年 | 12篇 |
2012年 | 24篇 |
2011年 | 21篇 |
2010年 | 10篇 |
2009年 | 16篇 |
2008年 | 28篇 |
2007年 | 28篇 |
2006年 | 21篇 |
2005年 | 22篇 |
2004年 | 15篇 |
2003年 | 8篇 |
2002年 | 15篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有301条查询结果,搜索用时 16 毫秒
61.
Shashikiran Donthamsetty Meera Brahmbhatt Vaishali Pannu Padmashree Rida Sujatha Ramarathinam Angela Ogden 《Cell cycle (Georgetown, Tex.)》2014,13(13):2056-2255
Centrosomes direct spindle morphogenesis to assemble a bipolar mitotic apparatus to enable error-free chromosome segregation and preclude chromosomal instability (CIN). Amplified centrosomes, a hallmark of cancer cells, set the stage for CIN, which underlies malignant transformation and evolution of aggressive phenotypes. Several studies report CIN and a tumorigenic and/or aggressive transformation in mitochondrial DNA (mtDNA)-depleted cells. Although several nuclear-encoded proteins are implicated in centrosome duplication and spindle organization, the involvement of mtDNA encoded proteins in centrosome amplification (CA) remains elusive. Here we show that disruption of mitochondrial function by depletion of mtDNA induces robust CA and mitotic aberrations in osteosarcoma cells. We found that overexpression of Aurora A, Polo-like kinase 4 (PLK4), and Cyclin E was associated with emergence of amplified centrosomes. Supernumerary centrosomes in rho0 (mtDNA-depleted) cells resulted in multipolar mitoses bearing “real” centrosomes with paired centrioles at the multiple poles. This abnormal phenotype was recapitulated by inhibition of respiratory complex I in parental cells, suggesting a role for electron transport chain (ETC) in maintaining numeral centrosomal homeostasis. Furthermore, rho0 cells displayed a decreased proliferative capacity owing to a G2/M arrest. Downregulation of nuclear-encoded p53 in rho0 cells underscores the importance of mitochondrial and nuclear genome crosstalk and may perhaps underlie the observed mitotic aberrations. By contrast, repletion of wild-type mtDNA in rho0 cells (cybrid) demonstrated a much lesser extent of CA and spindle multipolarity, suggesting partial restoration of centrosomal homeostasis. Our study provides compelling evidence to implicate the role of mitochondria in regulation of centrosome duplication, spindle architecture, and spindle pole integrity. 相似文献
62.
63.
64.
P. B. Kavi Kishor S. Anil Kumar Jalaja Naravula P. Hima Kumari Divya Kummari Rajasheker Guddimalli Sujatha Edupuganti Appa Rao Karumanchi Perumal Venkatachalam Prashanth Suravajhala Rathnagiri Polavarapu 《Physiology and Molecular Biology of Plants》2021,27(10):2433
Exploding global population, rapid urbanization, salinization of soils, decreasing arable land availability, groundwater resources, and dynamic climatic conditions pose impending damage to our food security by reducing the grain quality and quantity. This issue is further compounded in arid and semi-arid regions due to the shortage of irrigation water and erratic rainfalls. Millets are gluten (a family of proteins)-free and cultivated all over the globe for human consumption, fuel, feed, and fodder. They provide nutritional security for the under- and malnourished. With the deployment of strategies like foliar spray, traditional/marker-assisted breeding, identification of candidate genes for the translocation of important minerals, and genome-editing technologies, it is now tenable to biofortify important millets. Since the bioavailability of iron and zinc has been proven in human trials, the challenge is to make such grains accessible. This review encompasses nutritional benefits, progress made, challenges being encountered, and prospects of enriching millet crops with essential minerals. 相似文献
65.
Biochemical changes associated with adventitious shoot regeneration during in vitro culture of hypocotyl explants of Jatropha integerrima were determined. Histological and biochemical studies were undertaken at 7-d intervals, up to four weeks on hypocotyl explants cultured on basal Murashige and Skoog's medium supplemented with 0.5 mg dm-3 N6-benzyladenine and 1.0 mg dm-3 indole-3-butyric acid. Initial cell proliferation occurred within one week of culture; meristemoid differentiation within two to three weeks and shoot development after four weeks. Peak activities of alkaline phosphatase, peroxidase and polyphenol oxidase was observed at day 14 indicating their involvement in the formation of meristematic centers. Protein accumulation and acid phosphatase activity were maximum at day 28. 相似文献
66.
Cryptic promoter elements play a significant role in evolution of plant gene expression patterns and are prospective tools for creating gene expression systems in plants. In a previous report, a 452 bp promoter fragment designated as cryptic root-specific promoter (AY601849) was identified immediately upstream to T-DNA insertion, in the intergenic region between divergent genes SAHH1 and SHMT4, in T-DNA tagged mutant M57 of Arabidopsis thaliana. In silico analysis of 452 bp promoter revealed typical eukaryotic promoter architecture, presence of root-specific motifs and other cis-regulatory motifs responsible for the spatial and temporal expression. GUS expression driven by 452 bp in M57 was developmentally as well as light-regulated. The AT-rich 452 bp promoter does not show homology to any known sequences. The 452 bp promoter was further proved cryptic and detailed molecular characterization of the promoter carried out through serial 5′ and 3′ deletion analysis, by cloning the promoter fragments upstream to promoter-less GUS vector. A 279 bp fragment obtained by deleting 173 bp from 5′ end of 452 bp was capable of driving root-specific expression, similar to that of full-length promoter. Further, root tip-specific, root-specific and core-regulatory motifs for root-specific expression were identified at positions 173–227, 251–323 and 408–452 bp, respectively, from the 5′ end of 452 bp. The 452 bp promoter was equally functional in inverse orientation, hence bidirectional and symmetric. In heterologous systems, such as Brassica juncea and Oryza sativa, the promoter activity was not significant since GUS was not visually detected in transient assays. 相似文献
67.
Hongcheng Liu Christine Nowak Mei Shao Gomathinayagam Ponniah Alyssa Neill 《Biotechnology progress》2016,32(5):1103-1112
Recombinant monoclonal antibodies are commonly expressed in mammalian cell culture and purified by several steps of filtration and chromatography. The resulting high purity bulk drug substance still contains product variants differing in properties such as charge and size. Posttranslational modifications and degradations occurring during cell culture are the major sources of heterogeneity in bulk drug substance of recombinant monoclonal antibodies. The focus of the current review is the impact of cell culture conditions on the types and levels of various modifications and degradations of recombinant monoclonal antibodies. Understanding the relationship between cell culture and product variants can help to make consistently safe and efficacious products. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1103–1112, 2016 相似文献
68.
Keith C. Weiser Bin Liu Gwenn M. Hansen Darlene Skapura Kathryn E. Hentges Sujatha Yarlagadda Herbert C. Morse III Monica J. Justice 《Mammalian genome》2007,18(10):709-722
AKXD recombinant inbred (RI) strains develop a variety of leukemias and lymphomas due to somatically acquired insertions of
retroviral DNA into the genome of hematopoetic cells that can mutate cellular proto-oncogenes and tumor suppressor genes.
We generated a new set of tumors from nine AKXD RI strains selected for their propensity to develop B-cell tumors, the most
common type of human hematopoietic cancers. We employed a PCR technique called viral insertion site amplification (VISA) to
rapidly isolate genomic sequence at the site of provirus insertion. Here we describe 550 VISA sequence tags (VSTs) that identify
74 common insertion sites (CISs), of which 21 have not been identified previously. Several suspected proto-oncogenes and tumor
suppressor genes lie near CISs, providing supportive evidence for their roles in cancer. Furthermore, numerous previously
uncharacterized genes lie near CISs, providing a pool of candidate disease genes for future research. Pathway analysis of
candidate genes identified several signaling pathways as common and powerful routes to blood cancer, including Notch, E-protein,
NFκB, and Ras signaling. Misregulation of several Notch signaling genes was confirmed by quantitative RT-PCR. Our data suggest
that analyses of insertional mutagenesis on a single genetic background are biased toward the identification of cooperating
mutations. This tumor collection represents the most comprehensive study of the genetics of B-cell leukemia and lymphoma development
in mice. We have deposited the VST sequences, CISs in a genome viewer, histopathology, and molecular tumor typing data in
a public web database called VISION (Viral Insertion Sites Identifying Oncogenes), which is located at .
Keith C. Weiser and Bin Liu are authors that contributed equally to this work. 相似文献
69.
Changes in carbohydrate metabolism by triazole growth regulators in cassava (Manihot esculenta Crantz); effects on tuber production and quality 总被引:1,自引:0,他引:1
Gomathinayagam M Jaleel CA Lakshmanan GM Panneerselvam R 《Comptes rendus biologies》2007,330(9):644-655
We have evaluated the ability of two triazole growth regulators, viz. triadimefon (TDM) and hexaconazole (HEX), in the enhancement of tuber production and quality in cassava (Manihot esculenta Crantz) through their effects on carbohydrate metabolism. One litre of 20 mg(-1) TDM and 15 mg(-1) HEX solution per plant were used for the treatments and groundwater was given to control plants. Triazole treatments reduced plant height and leaf area, but increased fresh and dry weights. Plants treated with TDM showed an increased net assimilation rate, which is followed by HEX and control plants. Triazole compounds increased the relative growth rate of cassava after 200 DAP, i.e. in the phase of tuber enlargement. Triazole compounds increased the starch and other carbohydrate contents and carbohydrate metabolising enzyme activities. From the results of this study, it can be concluded that these triazoles can significantly enhance the tuber production and quality by affecting the starch metabolism, apart from their fungicidal properties. 相似文献
70.
Responses of antioxidant potentials in Dioscorea rotundata Poir. following paclobutrazol drenching 总被引:1,自引:0,他引:1
Jaleel CA Manivannan P Gomathinayagam M Sridharan R Panneerselvam R 《Comptes rendus biologies》2007,330(11):798-805
The effect of paclobutrazol (PBZ) treatments on the antioxidant metabolism of white yam (Dioscorea rotundata Poir.) was investigated in the present study. PBZ @ 15 mg l(-1) plant(-1) was given to plants by soil drenching, 30, 60, and 90 days after planting (DAP). The non-enzymatic antioxidant contents like ascorbic acid (AA), reduced glutathione (GSH) and alpha-tocopherol (alpha-toc), activities of antioxidant enzymes like superoxide dismutase (SOD), ascorbate peroxidase (APX), polyphenol oxidase (PPO) and catalase (CAT) were extracted and assayed on 100 DAP from leaf, stem and tubers of both control and PBZ treated plants. It was found that PBZ has a profound effect on the antioxidant metabolism and caused an enhancement in both non-enzymatic and enzymatic antioxidant potentials under treatments in white yam. Our results have good significance, as this increase the innate antioxidant potential of this food crop, which is helpful to satisfy the needs of antioxidants in diet and thereby make it an economically important food crop. 相似文献