全文获取类型
收费全文 | 391篇 |
免费 | 11篇 |
出版年
2024年 | 1篇 |
2022年 | 1篇 |
2021年 | 8篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 7篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 29篇 |
2014年 | 21篇 |
2013年 | 27篇 |
2012年 | 42篇 |
2011年 | 44篇 |
2010年 | 31篇 |
2009年 | 24篇 |
2008年 | 27篇 |
2007年 | 23篇 |
2006年 | 17篇 |
2005年 | 19篇 |
2004年 | 15篇 |
2003年 | 17篇 |
2002年 | 15篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有402条查询结果,搜索用时 31 毫秒
61.
Background
We previously developed small hybrid proteins consisting of SUMO-1 linked to an heptapeptide fused to the Tat protein transduction domain (PTD). The heptapeptide motif was selected from a library of random sequences to specifically bind HIV-1 regulatory proteins Tat or Rev. These constructs, named SHP, are able to enter primary lymphocytes and some of them inhibit HIV-1 replication. Considering these positive results and other data from the literature, we further tested the ability of ubiquitin or SUMO-1 linked to various PTD at their N-terminus to deliver within cells proteins or peptides fused downstream of their diglycine motif. In this system it is expected that the intracellular ubiquitin or SUMO-1 hydrolases cleave the PTD-Ub or PTD-SUMO-1 modules from the cargo polypeptide, thereby allowing its delivery under an unmodified form. 相似文献62.
63.
Reproductive biology of the andromonoecious Cucumis melo subsp. agrestis (Cucurbitaceae) 总被引:1,自引:0,他引:1
Leonie C. Kouonon Anne-Laure Jacquemart Arsene I. Zoro Bi Pierre Bertin Jean-Pierre Baudoin Yao Dje 《Annals of botany》2009,104(6):1129-1139
Background and Aims
Cucumis melo subsp. agrestis (Cucurbitaceae) is cultivated in many African regions for its edible kernels used as a soup thickener. The plant, an annual, andromonoecious, trailing-vine species, is of high social, cultural and economic value for local communities. In order to improve the yield of this crop, the first step and our aim were to elucidate its breeding system.Methods
Eight experimental pollination treatments were performed during three growing seasons to assess spontaneous selfing, self-compatibility and effects of pollen source (hermaphroditic vs. male flowers). Pollination success was determined by pollen tube growth and reproductive success was assessed by fruit, seed and seedling numbers and characteristics. The pollinator guild was surveyed and the pollination distance determined both by direct observations and by indirect fluorescent dye dispersal.Key Results
The species is probably pollinated by several Hymenoptera, principally by Hypotrigona para. Pollinator flight distances varied from 25 to 69 cm. No evidence for apomixis or spontaneous self-pollination in the absence of insect visitors was found. The self-fertility index (SFI = 0) indicated a total dependence on pollinators for reproductive success. The effects of hand pollination on fruit set, seed number and seedling fitness differed among years. Pollen tube growth and reproductive success did not differ between self- and cross-pollinations. Accordingly, a high self-compatibility index for the fruit set (SCI = 1·00) and the seed number (SCI = 0·98) and a low inbreeding depression at all developmental stages (cumulative δ = 0·126) suggest a high selfing ability. Finally, pollen origin had no effect on fruit and seed sets.Conclusions
This andromonoecious species has the potential for a mixed mating system with high dependence on insect-mediated pollination. The selfing rate through geitonogamy should be important. 相似文献64.
Todd J. Treangen Anne-Laure Abraham Marie Touchon & Eduardo P.C. Rocha 《FEMS microbiology reviews》2009,33(3):539-571
DNA repeats are causes and consequences of genome plasticity. Repeats are created by intrachromosomal recombination or horizontal transfer. They are targeted by recombination processes leading to amplifications, deletions and rearrangements of genetic material. The identification and analysis of repeats in nearly 700 genomes of bacteria and archaea is facilitated by the existence of sequence data and adequate bioinformatic tools. These have revealed the immense diversity of repeats in genomes, from those created by selfish elements to the ones used for protection against selfish elements, from those arising from transient gene amplifications to the ones leading to stable duplications. Experimental works have shown that some repeats do not carry any adaptive value, while others allow functional diversification and increased expression. All repeats carry some potential to disorganize and destabilize genomes. Because recombination and selection for repeats vary between genomes, the number and types of repeats are also quite diverse and in line with ecological variables, such as host-dependent associations or population sizes, and with genetic variables, such as the recombination machinery. From an evolutionary point of view, repeats represent both opportunities and problems. We describe how repeats are created and how they can be found in genomes. We then focus on the functional and genomic consequences of repeats that dictate their fate. 相似文献
65.
Faredin Alejevski Michelle Leemans Anne-Laure Gaillard David Leistenschneider Cline de Flori Marion Bougerol Sbastien Le Mvel Anthony Herrel Jean-Baptiste Fini Guillaume Pzeron Herv Tostivint 《Open biology》2021,11(8)
Urp1 and Urp2 are two neuropeptides of the urotensin II family identified in teleost fish and mainly expressed in cerebrospinal fluid (CSF)-contacting neurons. It has been recently proposed that Urp1 and Urp2 are required for correct axis formation and maintenance. Their action is thought to be mediated by the receptor Uts2r3, which is specifically expressed in dorsal somites. In support of this view, it has been demonstrated that the loss of uts2r3 results in severe scoliosis in adult zebrafish. In the present study, we report for the first time the occurrence of urp2, but not of urp1, in two tetrapod species of the Xenopus genus. In X. laevis, we show that urp2 mRNA-containing cells are CSF-contacting neurons. Furthermore, we identified utr4, the X. laevis counterparts of zebrafish uts2r3, and we demonstrate that, as in zebrafish, it is expressed in the dorsal somatic musculature. Finally, we reveal that, in X. laevis, the disruption of utr4 results in an abnormal curvature of the antero-posterior axis of the tadpoles. Taken together, our results suggest that the role of the Utr4 signalling pathway in the control of body straightness is an ancestral feature of bony vertebrates and not just a peculiarity of ray-finned fishes. 相似文献
66.
Anne-Laure Brochet Michel Gauthier-Clerc Raphaël Mathevet Arnaud Béchet Jean-Yves Mondain-Monval Alain Tamisier 《Biodiversity and Conservation》2009,18(7):1879-1894
Many wild species, like waterbirds, are exploited for their economic interests. At present, the annual western Palearctic
duck bag is at least 17 million birds. From a sustainable management perspective, wetland users and managers request predictions
of spatial distribution and abundance variations of these bird populations. The objective of this study was to analyze local
factors potentially influencing the diurnal distribution and population size of wintering ducks and coots, the main game species,
in Camargue (southern France). First, we showed that marshland surface area, salinity and hunting disturbance were the principal
variables explaining the duck and coot distribution. Secondly, we tested the hypothesis that hunting disturbance would reduce
the carrying capacity of the Camargue with two analyses: the effect of creating a protected area and the change of the hunting
closing date. This hypothesis was not validated. Our study therefore led us to reconsider the research orientations on the
carrying capacity in this wetland. The surface of protected day roosts seems presently sufficient in the Rhone delta. Consequently,
to increase the population size with the same level of hunting disturbance at the scale of the Camargue, alternative strategies
should be envisaged, such as the creation of nature reserves on nocturnal feeding ground or the creation of large management
units with limited disturbance. 相似文献
67.
Erwan G. Roussel Anne-Laure Sauvadet Carine Chaduteau Yves Fouquet Jean-Luc Charlou Daniel Prieur Marie-Anne Cambon Bonavita 《Environmental microbiology》2009,11(9):2446-2462
The distribution of the archaeal communities in deep subseafloor sediments [0–36 m below the seafloor (mbsf)] from the New Caledonia and Fairway Basins was investigated using DNA- and RNA-derived 16S rRNA clone libraries, functional genes and denaturing gradient gel electrophoresis (DGGE). A new method, Co-Migration DGGE (CM-DGGE), was developed to access selectively the active archaeal diversity. Prokaryotic cell abundances at the open-ocean sites were on average ∼3.5 times lower than at a site under terrestrial influence. The sediment surface archaeal community (0–1.5 mbsf) was characterized by active Marine Group 1 (MG-1) Archaea that co-occurred with ammonia monooxygenase gene ( amoA ) sequences affiliated to a group of uncultured sedimentary Crenarchaeota . However, the anoxic subsurface methane-poor sediments (below 1.5 mbsf) were dominated by less active archaeal communities, such as the Thermoplasmatales , Marine Benthic Group D and other lineages probably involved in the methane cycle ( Methanosarcinales , ANME-2 and DSAG/MBG-B). Moreover, the archaeal diversity of some sediment layers was restricted to only one lineage (Uncultured Euryarchaeota , DHVE6, MBG-B, MG-1 and SAGMEG). Sequences forming two clusters within the Thermococcales order were also present in these cold subseafloor sediments, suggesting that these uncultured putative thermophilic archaeal communities might have originated from a different environment. This study shows a transition between surface and subsurface sediment archaeal communities. 相似文献
68.
69.
Quettier AL Bertrand C Habricot Y Miginiac E Agnes C Jeannette E Maldiney R 《The Plant journal : for cell and molecular biology》2006,47(5):711-719
The plant hormone abscisic acid (ABA) controls numerous physiological traits: dormancy and germination of seeds, senescence and resistance to abiotic stresses. In order to get more insight into the role of protein tyrosine phosphatase (PTP) in ABA signalling, we obtained eight homozygous T-DNA insertion lines in Arabidopsis thaliana PTP genes. One mutant, named phs1-3, exhibited a strong ABA-induced inhibition of germination as only 26% of its seeds germinated after 3 days instead of 92% for the Columbia (Col-0) line. Genetic and molecular analyses of phs1-3 showed that it bears a unique T-DNA insertion in the promoter of the gene and that the mutation is recessive. PHS1 expression in the mutant is about half that of the Col-0 line. The upregulation of two ABA-induced genes (At5g06760, RAB18) and the downregulation of two ABA-repressed genes (AtCLC-A, ACL) are enhanced in the phs1-3 mutant compared with the wild-type. The 'in planta' aperture of phs1-3 stomata is reduced and the inhibition of the light-induced opening of stomata by ABA is stronger in phs1-3 leaves than in Col-0 leaves. Finally, PHS1 expression is upregulated in the presence of ABA in both phs1-3 and Col-0 but more intensively in the mutant. Thus, phs1-3 is hypersensitive to ABA. Taken together, these results show that PHS1, which encodes a dual-specificity PTP, is a negative regulator of ABA signalling. 相似文献
70.
Mercier A Devillard S Ngoubangoye B Bonnabau H Bañuls AL Durand P Salle B Ajzenberg D Dardé ML 《PLoS neglected tropical diseases》2010,4(11):e876