全文获取类型
收费全文 | 210篇 |
免费 | 37篇 |
国内免费 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 9篇 |
2015年 | 13篇 |
2014年 | 13篇 |
2013年 | 15篇 |
2012年 | 21篇 |
2011年 | 17篇 |
2010年 | 7篇 |
2009年 | 11篇 |
2008年 | 12篇 |
2007年 | 11篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 16篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1975年 | 2篇 |
排序方式: 共有248条查询结果,搜索用时 15 毫秒
61.
Achwak Benazza Jonathan Selleslagh Elsa Breton Khalef Rabhi Vincent Cornille Mahmoud Bacha Eric Lecuyer Rachid Amara 《PloS one》2015,10(1)
The inter-annual variability of the fish and macrocrustacean spring community on an intertidal sandy beach near the Canche estuary (North of France) was studied from 2000 to 2013 based on weekly spring sampling over an 11-year period. Twenty-eight species representing 21 families were collected during the course of the study. The community was dominated by a few abundant species accounting for > 99% of the total species densities. Most individuals caught were young-of-the-year indicating the importance of this ecosystem for juvenile fishes and macrocrustaceans. Although standard qualitative community ecology metrics (species composition, richness, diversity, evenness and similarity) indicated notable stability over the study period, community structure showed a clear change since 2009. Densities of P. platessa, P. microps and A. tobianus decreased significantly since 2009, whereas over the period 2010-2013, the contribution of S. sprattus to total species density increased 4-fold. Co-inertia and generalised linear model analyses identified winter NAO index, water temperature, salinity and suspended particular matter as the major environmental factors explaining these changes. Although the recurrent and dense spring blooms of the Prymnesiophyte Phaeocystis globosa is one of the main potential threats in shallow waters of the eastern English Channel, no negative impact of its temporal change was detected on the fish and macrocrustacean spring community structure. 相似文献
62.
Cherrier MV Girgenti E Amara P Iannello M Marchi-Delapierre C Fontecilla-Camps JC Ménage S Cavazza C 《Journal of biological inorganic chemistry》2012,17(5):817-829
Understanding the interaction of a protein with a relevant ligand is crucial for the design of an artificial metalloenzyme. Our own interest is focused on the synthesis of artificial monooxygenases. In an initial effort, we have used the periplasmic nickel-binding protein NikA from Escherichia coli and iron complexes in which N(2)Py(2) ligands (where Py is pyridine) have been varied in terms of charge, aromaticity, and size. Six "NikA/iron complex" hybrids have been characterized by X-ray crystallography, and their interactions and solution properties have been studied. The hybrids are stable as indicated by their K (d) values, which are all in the micromolar range. The X-ray structures show that the ligands interact with NikA through salt bridges with arginine residues and π-stacking with a tryptophan residue. We have further characterized these interactions using quantum mechanical calculations and determined that weak CH/π hydrogen bonds finely modulate the stability differences between hybrids. We emphasize the important role of the tryptophan residues. Thus, our study aims at the complete characterization of the factors that condition the interaction of an artificial ligand and a protein and their implications for catalysis. Besides its potential usefulness in the synthesis of artificial monooxygenases, our approach should be generally applicable in the field of artificial metalloenzymes. 相似文献
63.
Amara I Odena A Oliveira E Moreno A Masmoudi K Pagès M Goday A 《Plant & cell physiology》2012,53(2):312-329
LEA (late embryogenesis abundant) proteins participate in plant stress tolerance responses, but the mechanisms by which protection occurs are not fully understood. In the present work the unfolded proteins from maize dry embryos were analyzed by mass spectrometry. Twenty embryo proteins were identified, and among them 13 corresponded to LEA-type proteins. We selected three major LEA proteins, Emb564, Rab17 and Mlg3, belonging to groups 1, 2 and 3, respectively, and we undertook a comparative study in order to highlight differences among them. The post-translational modifications of native proteins were analyzed and the anti-aggregation properties of recombinant Emb564, Rab17 and Mgl3 proteins were evaluated in vitro. In addition, the protective effects of the LEA proteins were assessed in living cells under stress in Escherichia coli cells and in Nicotiana bentamiana leaves agroinfiltrated with fluorescent LEA-green fluorescent protein (GFP) fusions. Protein visualization by confocal microscopy indicated that cells expressing Mg3-GFP showed reduced cell shrinkage effects during dehydration and that Rab17-GFP co-localized to leaf oil bodies after heat shock. Overall, the results highlight differences and suggest functional diversity among maize LEA groups. 相似文献
64.
Leighton BH Seal RP Watts SD Skyba MO Amara SG 《The Journal of biological chemistry》2006,281(40):29788-29796
Structure-function studies of mammalian and bacterial excitatory amino acid transporters (EAATs), as well as the crystal structure of a related archaeal glutamate transporter, support a model in which TM7, TM8, and the re-entrant loops HP1 and HP2 participate in forming a substrate translocation pathway within each subunit of a trimer. However, the transport mechanism, including precise binding sites for substrates and co-transported ions and changes in the tertiary structure underlying transport, is still not known. In this study, we used chemical cross-linking of introduced cysteine pairs in a cysteine-less version of EAAT1 to examine the dynamics of key domains associated with the translocation pore. Here we show that cysteine substitution at Ala-395, Ala-367, and Ala-440 results in functional single and double cysteine transporters and that in the absence of glutamate or dl-threo-beta-benzyloxyaspartate (dl-TBOA), A395C in the highly conserved TM7 can be cross-linked to A367C in HP1 and to A440C in HP2. The formation of these disulfide bonds is reversible and occurs intra-molecularly. Interestingly, cross-linking A395C to A367C appears to abolish transport, whereas cross-linking A395C to A440C lowers the affinities for glutamate and dl-TBOA but does not change the maximal transport rate. Additionally, glutamate and dl-TBOA binding prevent cross-linking in both double cysteine transporters, whereas sodium binding facilitates cross-linking in the A395C/A367C transporter. These data provide evidence that within each subunit of EAAT1, Ala-395 in TM7 resides close to a residue at the tip of each re-entrant loop (HP1 and HP2) and that these residues are repositioned relative to one another at different steps in the transport cycle. Such behavior likely reflects rearrangements in the tertiary structure of the translocation pore during transport and thus provides constraints for modeling the structural dynamics associated with transport. 相似文献
65.
Sirilug Magerd Monsicha Somrit Parichat Prachaney Amara Thongpan Kannika Chatchavalvanich Prapee Sretarugsa Wattana Weerachatyanukul 《Cell and tissue research》2009,336(2):267-276
Our aim has been to determine whether carbohydrate distribution in the oviducts of progesterone-treated animals is comparable
with that of seasonal breeders in Rana tigrina. Like many other anurans, R. tigrina oviduct exhibits a short straight portion (pars recta, pr) at the beginning followed by a long, highly coiled portion (pars
convoluta, pc). Histologically, the oviduct of this species revealed some unique features, one of which was intense toluidine
blue staining, specifically in the upper mucosal glands of pc4. Based on lectin reactivities in the epithelial cells and mucosal
glands, patterns of lectin staining in the seasonal breeders were classified into seven types: R1-R3 (for pr) and C1-C4 (for
pc). Typically, some lectins reacted selectively either with ciliated cells (concanavalin A) or non-cialiated cells (Ricinus communis agglutinin I and wheatgerm agglutinin); however, Bandeiraea simplicifolia agglutinin I reacted with both cell types. These staining patterns were different in the progesterone-treated animals. Differences
in glycan distribution in the oviductal secretions were revealed by lectin blotting. Compared with the seasonal breeders,
an enhanced staining of some lectins was noted in the hormone-treated animals: either an increased staining intensity of existing
protein bands or additional staining of new protein bands. Inversely, the staining of wheatgerm agglutinin was markedly diminished
in the hormone-treated animals, suggesting the inhibitory effect of progesterone on oviductal glycan distribution. Whether
alteration in glycan distribution upon progesterone treatment affects the physiological properties of the released jelly substances
remains to be addressed.
This research was supported by Thailand Research Funds (to W.W.), a Research Initiate Grant from Kasetsart University (to
A.T.), and Mahidol University. 相似文献
66.
67.
68.
Chitra Seetharam Suvarna Soundarajan Ambuja C. Udas Amara Sambasiva Rao Shree Kumar Apte 《Process Biochemistry》2009,44(2):246-250
The phoN gene, encoding a non-specific acid phosphatase from Salmonella enterica sv. Typhi, was cloned and overexpressed into Escherichia coli. The E. coli cells bearing phoN showed high acid phosphatase activity and removed 83% of cadmium from a 1 mM solution in 3 h, when provided with 5 mM β-glycerophosphate as a source of phosphate. Such cells, when lyophilized without any lyo/cryoprotectant, were rendered non-viable but fully retained cadmium precipitation ability. Lyophilized recombinant cells could be stored at room temperature, without significant loss of activity for up to 6 months, and removed upto 21 g cadmium/g dry weight. The precipitated cadmium could be easily recovered from the cells by dilute acid wash, following which the cells retained their cadmium precipitation ability, facilitating their reuse. The use of genetically engineered, non-viable E. coli cells offers an environmentally safe biotechnology for bioremediation of cadmium from contaminated sites. 相似文献
69.
Martin Di Grandi Matthew Olson Amar S. Prashad Geraldine Bebernitz Amara Luckay Stanley Mullen Yongbo Hu Girija Krishnamurthy Keith Pitts John O’Connell 《Bioorganic & medicinal chemistry letters》2010,20(1):398-402
Two classes of compounds, thiocarbamates 1 and triazoles 2, have been identified as HIV RT RNase H inhibitors using a novel FRET-based HTS assay. The potent analogs in each series exhibited selectivity and were active in cell-based assays. In addition, saturable, 1:1 stoichiometric binding to target was established and time of addition studies were consistent with inhibition of RT-mediated HIV replication. 相似文献
70.
Dominique Lesuisse Gilles Tiraboschi Alain Krick Pierre-Yves Abecassis Gilles Dutruc-Rosset Didier Babin Frank Halley Fabienne Châtreau Sylvette Lachaud Alain Chevalier Dominique Quarteronet Marie-Claude Burgevin Céline Amara Philippe Bertrand Thomas Rooney 《Bioorganic & medicinal chemistry letters》2010,20(7):2344-2349
From potent and selective inhibitors of GSK3β displaying CYP1A2 inhibition and poor PK properties, mostly linked to metabolic instability and in vivo hydrolysis of the amide bond, we were able to obtain safe and orally available inhibitors with good half lives. 相似文献