首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   99篇
  免费   0篇
  2021年   1篇
  2018年   1篇
  2017年   2篇
  2016年   1篇
  2015年   1篇
  2014年   1篇
  2013年   4篇
  2012年   3篇
  2011年   4篇
  2010年   3篇
  2009年   1篇
  2008年   3篇
  2007年   2篇
  2006年   5篇
  2005年   6篇
  2004年   4篇
  2003年   3篇
  2002年   2篇
  2001年   4篇
  2000年   3篇
  1999年   3篇
  1998年   2篇
  1996年   1篇
  1995年   1篇
  1994年   3篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1988年   1篇
  1987年   4篇
  1986年   1篇
  1985年   3篇
  1984年   3篇
  1983年   2篇
  1981年   4篇
  1980年   1篇
  1979年   2篇
  1978年   2篇
  1977年   2篇
  1972年   3篇
  1970年   1篇
  1969年   1篇
排序方式: 共有99条查询结果,搜索用时 15 毫秒
31.
Local knowledge systems are not considered in the conservation of fragile seagrass marine ecosystems. In fact, little is known about the utility of seagrasses in local coastal communities. This is intriguing given that some local communities rely on seagrasses to sustain their livelihoods and have relocated their villages to areas with a rich diversity and abundance of seagrasses. The purpose of this study is to assist in conservation efforts regarding seagrasses through identifying Traditional Ecological Knowledge (TEK) from local knowledge systems of seagrasses from 40 coastal communities along the eastern coast of India. We explore the assemblage of scientific and local traditional knowledge concerning the 1. classification of seagrasses (comparing scientific and traditional classification systems), 2. utility of seagrasses, 3. Traditional Ecological Knowledge (TEK) of seagrasses, and 4. current conservation efforts for seagrass ecosystems. Our results indicate that local knowledge systems consist of a complex classification of seagrass diversity that considers the role of seagrasses in the marine ecosystem. This fine-scaled ethno-classification gives rise to five times the number of taxa (10 species = 50 local ethnotaxa), each with a unique role in the ecosystem and utility within coastal communities, including the use of seagrasses for medicine (e.g., treatment of heart conditions, seasickness, etc.), food (nutritious seeds), fertilizer (nutrient rich biomass) and livestock feed (goats and sheep). Local communities are concerned about the loss of seagrass diversity and have considerable local knowledge that is valuable for conservation and restoration plans. This study serves as a case study example of the depth and breadth of local knowledge systems for a particular ecosystem that is in peril.  相似文献   
32.
The structure–activity relationships of T0901317 analogs were explored as RORc inverse agonists using the principles of property- and structure-based drug design. An X-ray co-crystal structure of T0901317 and RORc was obtained and provided molecular insight into why T0901317 functioned as an inverse agonist of RORc; whereas, the same ligand functioned as an agonist of FXR, LXR, and PXR. The structural data was also used to design inhibitors with improved RORc biochemical and cellular activities. The improved inhibitors possessed enhanced selectivity profiles (rationalized using the X-ray crystallographic data) against other nuclear receptors.  相似文献   
33.
Survivin is a member of the IAP (inhibitor of apoptosis) protein family, defined in part by the presence of a zinc-binding baculoviral inhibitory repeat (BIR) domain. Most BIR domains bind short sequences beginning with alanine, and in this manner, they recognize and block the action of key targets in apoptotic pathways. However, Survivin binds only very weakly to typical IAP ligands. Unique features of Survivin are the long C-terminal helix following the BIR domain and a short segment (linking the helix and BIR domains) that mediates Survivin homodimerization. Despite this detailed knowledge of the structure of Survivin itself, there is a current lack of understanding about how Survivin recognizes cellular binding partners, and consequently, many questions about Survivin function remain unanswered. We determined two co-crystal structures of Survivin and a minimal binding fragment from the chromosomal passenger protein Borealin, a well validated functional interactor. The interaction between Survivin and Borealin involves extensive packing between the long C-terminal helix of Survivin and a long Borealin helix. Surprisingly, an additional important interaction occurs between the Survivin homodimerization interface and a short segment of Borealin. This segment both structurally mimics and displaces one Survivin monomer. The relevance of this unexpected interaction was tested by mutagenesis of two key Borealin residues. Mutant Borealin introduced into HeLa cells failed to localize properly during mitosis and also caused mislocalization of other chromosomal passenger proteins. This suggests that the mutant is dominant-negative and confirms the functional importance of the interaction surface identified in the crystal structures.  相似文献   
34.
Activation of the proapoptotic receptor death receptor5 (DR5) in various cancer cells triggers programmed cell death through the extrinsic pathway. We have generated a fully human monoclonal antibody (Apomab) that induces tumor cell apoptosis through DR5 and investigated the structural features of its interaction with DR5. Biochemical studies showed that Apomab binds DR5 tightly and selectively. X-ray crystallographic analysis of the complex between the Apomab Fab fragment and the DR5 ectodomain revealed an interaction epitope that partially overlaps with both regions of the Apo2 ligand/tumor necrosis factor-related apoptosis-inducing ligand binding site. Apomab induced DR5 clustering at the cell surface and stimulated a death-inducing signaling complex containing the adaptor molecule Fas-associated death domain and the apoptosis-initiating protease caspase-8. Fc crosslinking further augmented Apomab's proapoptotic activity. In vitro, Apomab triggered apoptosis in cancer cells, while sparing normal hepatocytes even upon anti-Fc crosslinking. In vivo, Apomab exerted potent antitumor activity as a single agent or in combination with chemotherapy in xenograft models, including those based on colorectal, non-small cell lung and pancreatic cancer cell lines. These results provide structural and functional insight into the interaction of Apomab with DR5 and support further investigation of this antibody for cancer therapy.  相似文献   
35.
Differences in starch metabolism during seed development and germination of two soybean [ Glycine max (L.) Merrill] genotypes with normal seed β-amylase activity ['Williams' ( Sp 1b and 'Altona' ( Sp 1b)] and two soybean genotypes with undetectable seed β-amylase activity ['Chestnut' ( Sp 1au) and 'Altona' ( Sp 1)] were investigated. Starch and soluble sugar profiles were essentially the same during seed development and germination. Total amylase activity of Williams and Altona ( Sp 1b) peaked just prior to seed maturity and then dropped off slowly; whereas, the total amylase activity of Chestnut and Altona ( sp 1) was very low throughout seed development and germination. The differences in amylase activity between Altona ( Sp 1 b) and Altona ( sp 1) was also seen in leaves. α-Amylase activity was similar in the four genotypes when β-amylase was inhibited with Hg2+ but was higher in the two genotypes with normal β-amylase activity when β-amylase was inhibited with heat plus Ca2+. Low levels of starch phosphorylase activity were detected throughout seed development and germination, and the activity was similar in three of the genotypes and higher in Altona ( sp 1).
The protein, oil and oligosaccharide contents of mature seeds of the four genotypes were similar. Altona ( sp 1 b) and ( sp 1), which appear to be near isogenic lines, were not different in any morphological character or yield.
Altona ( Sp 1 b) showed greater hydrolysis of soybean seed starch than Altona ( sp 1), but the evidence indicates that the mutation resulting in greatly reduced or missing β-amylase activity has no effect on starch metabolism of developing and germinating soybean seeds.  相似文献   
36.
Summary Only legumes of the cowpea cross-inoculation group, including the winged bean (Psophocarpus tetragonolobus) were found to form nodules in a temperate zone soil with no previous history of legume cropping. Isolates from root nodules from uninoculated winged beans grown in the field only nodulated legumes in the cowpea cross-inoculation group.Rhizobium japonicum formed ineffective nodules with the winged bean. Contribution No.5852, Scientific Article No.A2802 of the Maryland Agricultural Experiment Station, Department of Botany.  相似文献   
37.
Events leading to the planting of the first soybeans in Illinois and the subsequent distribution of the seed throughout the United States are documented. In December 1850 theAuckland left Hong Kong for San Francisco. The ship came across a Japanese junk floundering on the sea. The Japanese crew was removed from the junk and placed on board theAuckland, which continued on to San Francisco. In March 1851 Dr. Benjamin Franklin Edwards obtained soybean seeds from the Japanese and brought the seeds to Alton, Illinois. Mr. John H. Lea of Alton planted the soybeans in his garden in summer 1851. These events took place 3 yr prior to the famous introduction of soybeans from Japan into the United States by the Perry Expedition.  相似文献   
38.
The genus Glycine Willd. is divided into three subgenera, Glycine Willd., Soja (Moench) F. J. Herm., and Bracteata Verdc. Six species are currently recognized in the subgenus Glycine: G. canescens F. J. Herm., G. clandestina Willd., G. falcata Benth., G. latrobeana (Meissn.) Benth., G. tabacina (Labill.) Benth., and G. tomentella Hayata. Distribution of the subgenus extends from south China to Tasmania and includes several Pacific islands. A collection of these species was examined cytologically and morphologically in an attempt to evaluate existing variability between and within taxa. Chromosome counts confirmed G. canescens, G. clandestina and G. falcata to be diploid with 2n = 40. Both tetraploids (2n = 80) and diploids were found in G. tabacina, the latter restricted to Australia. Glycine tomentella accessions were primarily tetraploid, but several collections from New South Wales, Australia, were found to be aneuploid with 78 chromosomes. One collection was aneuploid at the diploid level with 38 chromosomes. Meiosis appeared normal in the aneuploids with regular bivalent formation. Several accessions previously identified as G. tomentella were diploid. Seed of G. latrobeana was not available for analysis. Numerical techniques in the form of cluster analysis and principal components analysis were applied to morphological data on vegetative and inflorescence characters obtained from each collection. Numerical analysis grouped the accessions essentially according to current species delimitations with some exceptions. Glycine tabacina specimens from Taiwan approached G. clandestina in several characteristics. The diploid G. tomentella specimens formed a separate cluster and appeared morphologically distinct from the remaining taxa.  相似文献   
39.
Seed protein extracts from 477 Japanese soybean cultivars were analyzed by polyaery lamide gel electrophoresis to determine the distribution of the alleles of the Ti (Ti a,Ti b,Ti c) and Sp1 (Sp 1 a,Sp 1 b loci with respect to maturity group and district of adaptation of each cultivar. About 60 percent of the soybean cultivars had theTi a allele. The frequency of theTi b allele was found to be highest in the southeast district and lowest in the northeast district. TheTi c allele discovered in 6 cultivars was traced to two possible sources adapted in the Tohoku District. TheSp l a, allele was found in 26 cultivars ranging from Maturity Group II through VIII. The summer season type cultivars adapted to the Kyushu District having the genotypeTi b Spl b probably played a major role in the peculiar accumulation of theTi ub allele and the decrease of theSp l a allele in the Japanese soybean cultivar population.  相似文献   
40.

Background  

Spectral counting is a shotgun proteomics approach comprising the identification and relative quantitation of thousands of proteins in complex mixtures. However, this strategy generates bewildering amounts of data whose biological interpretation is a challenge.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号