全文获取类型
收费全文 | 420篇 |
免费 | 63篇 |
出版年
2021年 | 6篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 18篇 |
2015年 | 12篇 |
2014年 | 14篇 |
2013年 | 11篇 |
2012年 | 20篇 |
2011年 | 22篇 |
2010年 | 9篇 |
2009年 | 5篇 |
2008年 | 14篇 |
2007年 | 22篇 |
2006年 | 16篇 |
2005年 | 14篇 |
2004年 | 14篇 |
2003年 | 17篇 |
2002年 | 14篇 |
2001年 | 16篇 |
2000年 | 16篇 |
1999年 | 10篇 |
1998年 | 19篇 |
1997年 | 11篇 |
1996年 | 13篇 |
1995年 | 14篇 |
1994年 | 3篇 |
1993年 | 10篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1971年 | 5篇 |
1969年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有483条查询结果,搜索用时 26 毫秒
81.
Benjamin T Julius Tyler J McCubbin Rachel A Mertz Nick Baert Jan Knoblauch DeAna G Grant Kyle Conner Saadia Bihmidine Paul Chomet Ruth Wagner Jeff Woessner Karen Grote Jeanette Peevers Thomas L Slewinski Maureen C McCann Nicholas C Carpita Michael Knoblauch David M Braun 《The Plant cell》2021,33(10):3348
Carbohydrate partitioning from leaves to sink tissues is essential for plant growth and development. The maize (Zea mays) recessive carbohydrate partitioning defective28 (cpd28) and cpd47 mutants exhibit leaf chlorosis and accumulation of starch and soluble sugars. Transport studies with 14C-sucrose (Suc) found drastically decreased export from mature leaves in cpd28 and cpd47 mutants relative to wild-type siblings. Consistent with decreased Suc export, cpd28 mutants exhibited decreased phloem pressure in mature leaves, and altered phloem cell wall ultrastructure in immature and mature leaves. We identified the causative mutations in the Brittle Stalk2-Like3 (Bk2L3) gene, a member of the COBRA family, which is involved in cell wall development across angiosperms. None of the previously characterized COBRA genes are reported to affect carbohydrate export. Consistent with other characterized COBRA members, the BK2L3 protein localized to the plasma membrane, and the mutants condition a dwarf phenotype in dark-grown shoots and primary roots, as well as the loss of anisotropic cell elongation in the root elongation zone. Likewise, both mutants exhibit a significant cellulose deficiency in mature leaves. Therefore, Bk2L3 functions in tissue growth and cell wall development, and this work elucidates a unique connection between cellulose deposition in the phloem and whole-plant carbohydrate partitioning.Mutations in Bk2L3 result in dwarfed plants with decreased anisotropic cell growth, cellulose deposition, phloem pressure, sucrose export, and carbohydrate hyperaccumulation in mature maize leaves. 相似文献
82.
83.
84.
85.
86.
Integrative analyses reveal signaling pathways underlying familial breast cancer susceptibility 下载免费PDF全文
Stephen R Piccolo Laura M Hoffman Thomas Conner Gajendra Shrestha Adam L Cohen Jeffrey R Marks Leigh A Neumayer Cori A Agarwal Mary C Beckerle Irene L Andrulis Avrum E Spira Philip J Moos Saundra S Buys William Evan Johnson Andrea H Bild 《Molecular systems biology》2016,12(3)
The signaling events that drive familial breast cancer (FBC) risk remain poorly understood. While the majority of genomic studies have focused on genetic risk variants, known risk variants account for at most 30% of FBC cases. Considering that multiple genes may influence FBC risk, we hypothesized that a pathway‐based strategy examining different data types from multiple tissues could elucidate the biological basis for FBC. In this study, we performed integrated analyses of gene expression and exome‐sequencing data from peripheral blood mononuclear cells and showed that cell adhesion pathways are significantly and consistently dysregulated in women who develop FBC. The dysregulation of cell adhesion pathways in high‐risk women was also identified by pathway‐based profiling applied to normal breast tissue data from two independent cohorts. The results of our genomic analyses were validated in normal primary mammary epithelial cells from high‐risk and control women, using cell‐based functional assays, drug‐response assays, fluorescence microscopy, and Western blotting assays. Both genomic and cell‐based experiments indicate that cell–cell and cell–extracellular matrix adhesion processes seem to be disrupted in non‐malignant cells of women at high risk for FBC and suggest a potential role for these processes in FBC development. 相似文献
87.
M. O’Callaghan E. M. Gerard N. W. Waipara S. D. Young T. R. Glare P. J. Barrell A. J. Conner 《Plant and Soil》2005,266(1-2):47-56
Antimicrobial peptide magainin II, isolated from the skin of the African clawed toad, has shown activity in vitro against a range of micro-organisms. Transgenic potato lines expressing a synthetic magainin gene show improved resistance
to the bacterial plant pathogen, Erwinia carotovora. Culturable bacterial and fungal communities associated with magainin-producing potato plants were compared with those communities
from the non-transgenic parental control and with another potato cultivar. Total numbers of aerobic bacteria recovered from
the leaves of the magainin-producing line, its non-transgenic parent line and an unrelated cultivar did not differ significantly.
There were no detectable differences in the numbers of Gram-positive and Gram-negative bacteria, pseudomonad populations or
fungi recovered from foliage from the three plant lines. Bacterial populations recovered from the roots of a magainin-expressing
plant line did not differ significantly from populations recovered from the unmodified parental line. Tubers from the magainin-expressing
transgenic potatoes, however, had significantly lower total numbers of bacteria than tubers produced by unmodified plants.
In vitro testing of rhizosphere isolates against magainin analogues found that bacterial isolates varied in their susceptibility to
the peptides. There were no significant differences in the total numbers of fungi and yeasts recovered from the various plant
lines, with one exception: higher numbers of fungi were recovered from roots of magainin-expressing plants than the unmodified
control plants. 相似文献
88.
Kyle A. Hollister Elizabeth S. Conner Xinxing Zhang Mark Spell Gary M. Bernard Pratik Patel Ana Carolina G.V. de Carvalho Rebecca A. Butcher Justin R. Ragains 《Bioorganic & medicinal chemistry》2013,21(18):5754-5769
The nematode Caenorhabditis elegans secretes ascarosides, structurally diverse derivatives of the 3,6-dideoxysugar ascarylose, and uses them in chemical communication. At high population densities, specific ascarosides, which are together known as the dauer pheromone, trigger entry into the stress-resistant dauer larval stage. In order to study the structure–activity relationships for the ascarosides, we synthesized a panel of ascarosides and tested them for dauer-inducing activity. This panel includes a number of natural ascarosides that were detected in crude pheromone extract, but as yet have no assigned function, as well as many unnatural ascaroside derivatives. Most of these ascarosides, some of which have significant structural similarity to the natural dauer pheromone components, have very little dauer-inducing activity. Our results provide a primer to ascaroside structure–activity relationships and suggest that slight modifications to ascaroside structure dramatically influence binding to the relevant G protein-coupled receptors that control dauer formation. 相似文献
89.
90.
Gregory B. Noe Ken W. Krauss B. Graeme Lockaby William H. Conner Cliff R. Hupp 《Biogeochemistry》2013,114(1-3):225-244
Tidal freshwater wetlands are sensitive to sea level rise and increased salinity, although little information is known about the impact of salinification on nutrient biogeochemistry in tidal freshwater forested wetlands. We quantified soil nitrogen (N) and phosphorus (P) mineralization using seasonal in situ incubations of modified resin cores along spatial gradients of chronic salinification (from continuously freshwater tidal forest to salt impacted tidal forest to oligohaline marsh) and in hummocks and hollows of the continuously freshwater tidal forest along the blackwater Waccamaw River and alluvial Savannah River. Salinification increased rates of net N and P mineralization fluxes and turnover in tidal freshwater forested wetland soils, most likely through tree stress and senescence (for N) and conversion to oligohaline marsh (for P). Stimulation of N and P mineralization by chronic salinification was apparently unrelated to inputs of sulfate (for N and P) or direct effects of increased soil conductivity (for N). In addition, the tidal wetland soils of the alluvial river mineralized more P relative to N than the blackwater river. Finally, hummocks had much greater nitrification fluxes than hollows at the continuously freshwater tidal forested wetland sites. These findings add to knowledge of the responses of tidal freshwater ecosystems to sea level rise and salinification that is necessary to predict the consequences of state changes in coastal ecosystem structure and function due to global change, including potential impacts on estuarine eutrophication. 相似文献