全文获取类型
收费全文 | 92篇 |
免费 | 7篇 |
出版年
2022年 | 1篇 |
2016年 | 4篇 |
2015年 | 9篇 |
2014年 | 5篇 |
2013年 | 7篇 |
2012年 | 5篇 |
2011年 | 4篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 7篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 7篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 8篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有99条查询结果,搜索用时 31 毫秒
91.
M. Leonardi M. Iotti M. Oddis G. Lalli G. Pacioni P. Leonardi S. Maccherini C. Perini E. Salerni A. Zambonelli 《Mycorrhiza》2013,23(5):349-358
The ectomycorrhizal (ECM) fungal communities of four natural Tuber magnatum truffle grounds, located in different Italian regions (Abruzzo, Emilia-Romagna, Molise, and Tuscany), were studied. The main objective of this study was to characterize and compare the ECM fungal communities in the different regions and in productive (where T. magnatum ascomata were found) and nonproductive points. More than 8,000 (8,100) colonized root tips were counted in 73 soil cores, and 129 operational taxonomic units were identified using morphological and molecular methods. Although the composition of the ECM fungal communities studied varied, we were able to highlight some common characteristics. The most plentiful ECM fungal taxa belong to the Thelephoraceae and Sebacinaceae families followed by Inocybaceae and Russulaceae. Although several ectomycorrhizas belonging to Tuber genus were identified, no T. magnatum ectomycorrhizas were found. The putative ecological significance of some species is discussed. 相似文献
92.
93.
94.
Increased steroidogenic factor-1 dosage triggers adrenocortical cell proliferation and cancer 总被引:1,自引:0,他引:1
95.
Galit Kuznets Elena Vigonsky Ziva Weissman Daniela Lalli Tsvia Gildor Sarah J. Kauffman Paola Turano Jeffrey Becker Oded Lewinson Daniel Kornitzer 《PLoS pathogens》2014,10(10)
Iron scavenging constitutes a crucial challenge for survival of pathogenic microorganisms in the iron-poor host environment. Candida albicans, like many microbial pathogens, is able to utilize iron from hemoglobin, the largest iron pool in the host''s body. Rbt5 is an extracellular glycosylphosphatidylinositol (GPI)-anchored heme-binding protein of the CFEM family that facilitates heme-iron uptake by an unknown mechanism. Here, we characterize an additional C. albicans CFEM protein gene, PGA7, deletion of which elicits a more severe heme-iron utilization phenotype than deletion of RBT5. The virulence of the pga7−/− mutant is reduced in a mouse model of systemic infection, consistent with a requirement for heme-iron utilization for C. albicans pathogenicity. The Pga7 and Rbt5 proteins exhibit distinct cell wall attachment, and discrete localization within the cell envelope, with Rbt5 being more exposed than Pga7. Both proteins are shown here to efficiently extract heme from hemoglobin. Surprisingly, while Pga7 has a higher affinity for heme in vitro, we find that heme transfer can occur bi-directionally between Pga7 and Rbt5, supporting a model in which they cooperate in a heme-acquisition relay. Together, our data delineate the roles of Pga7 and Rbt5 in a cell surface protein network that transfers heme from extracellular hemoglobin to the endocytic pathway, and provide a paradigm for how receptors embedded in the cell wall matrix can mediate nutrient uptake across the fungal cell envelope. 相似文献
96.
Regulation of steroidogenesis and the steroidogenic acute regulatory protein by a member of the cAMP response-element binding protein family. 总被引:7,自引:0,他引:7
97.
98.
The gymnosomatous pteropod Clione limacina (Phipps) assimilated carbon from its prey Spiratella retroversa (Fleming) with greater than 90 % efficiency and with nearly 100 % efficiency for nitrogen.The respiratory rate of Clione was found to vary with locality and season, but the weight exponent did not differ significantly nor was it affected by temperature. Starving animals lost weight about twice as rapidly as would be predicted from the respiratory rate, but the rate of loss was unaffected by temperature over the normal range (2–17 °C) for the animal. A T-line of Paloheimo and Dickie calculated from the rate of weight loss had approximately the same slope as that obtained from direct respirometry, but a significantly greater slope (weight exponent) than those obtained for T-lines calculated from growth experiments. Feeding also greatly increased the level of metabolism, suggesting that a fed animal might be twenty times more metabolically active than a starved one.First order growth efficiency K1 for Clione was often in excess of 50 % lending further support to the hypothesis that the prey is virtually all “physiologically useful ration”. K-lines of Paloheimo and Dickie calculated for individual Clione grown over a period of weeks showed no significant slope whether log K was plotted against size of predator (Clione), amount of prey ingested (Spiratella) or mean size of the prey. Multiple regression and correlation analyses suggest that a negative slope for the K-line would result if an animal were grown with a constant size of food. Increasing the ration markedly, by increasing both temperature and size of prey as the predator grew, tended to maintain the slope of the K-line near to zero. 相似文献
99.
Yingjie Yu Shailender S Kanwar Bhaumik B Patel Jyoti Nautiyal Fazlul H Sarkar Adhip PN Majumdar 《Translational oncology》2009,2(4):321-328
5-Fluorouracil (5-FU) or 5-FU plus oxaliplatin (FOLFOX) remains the backbone of colorectal cancer chemotherapeutics but with limited success. This could partly be due to the enrichment of cancer stem cells (CSCs) that are resistant to conventional chemotherapy. Therefore, validation of a nontoxic agent that can either cause reversal of chemoresistance or promote the killing of CSCs would be highly desirable. The current study examines whether curcumin, the major active ingredient of turmeric, either alone or together with FOLFOX, would be an effective strategy to eliminate colon CSCs. Exposure of colon cancer HCT-116 or HT-29 cells to FOLFOX that inhibited their growth led to the enrichment of CSC phenotype as evidenced by increased proportion of CD133-, CD44-, and/or CD166-positive cells and epidermal growth factor receptor (EGFR) levels. Treatment of FOLFOX-surviving colon cancer cells with either curcumin alone or together with FOLFOX resulted in a marked reduction in CSCs, as evidenced by the decreased expression of CD44 and CD166 as well as EGFR and by their ability to form anchorage-dependent colonies. They also caused disintegration of colonospheres. Increased expression of EGFR in FOLFOX-surviving cells could be attributed to hypomethylation of the EGFR promoter, whereas an opposite phenomenon was observed when the FOLFOX-surviving cells were treated with curcumin and/or FOLFOX. These changes were accompanied by parallel alterations in the levels of DNA methyltransferase 1. In conclusion, our data suggest that curcumin by itself or together with the conventional chemotherapeutic could be an effective treatment strategy for preventing the emergence of chemoresistant colon cancer cells by reducing/eliminating CSCs. 相似文献