全文获取类型
收费全文 | 714篇 |
免费 | 48篇 |
出版年
2024年 | 1篇 |
2023年 | 9篇 |
2022年 | 24篇 |
2021年 | 40篇 |
2020年 | 35篇 |
2019年 | 26篇 |
2018年 | 32篇 |
2017年 | 18篇 |
2016年 | 30篇 |
2015年 | 60篇 |
2014年 | 62篇 |
2013年 | 70篇 |
2012年 | 51篇 |
2011年 | 54篇 |
2010年 | 34篇 |
2009年 | 36篇 |
2008年 | 34篇 |
2007年 | 28篇 |
2006年 | 31篇 |
2005年 | 18篇 |
2004年 | 15篇 |
2003年 | 7篇 |
2002年 | 13篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1971年 | 3篇 |
1969年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有762条查询结果,搜索用时 15 毫秒
111.
Maxime Lenormand Guillaume Papuga Olivier Argagnon Maxence Soubeyrand Guilhem De Barros Samuel Alleaume Sandra Luque 《Ecology and evolution》2019,9(1):237-250
The delimitation of bioregions helps to understand historical and ecological drivers of species distribution. In this work, we performed a network analysis of the spatial distribution patterns of plants in south of France (Languedoc‐Roussillon and Provence‐Alpes‐Côte d'Azur) to analyze the biogeographical structure of the French Mediterranean flora at different scales. We used a network approach to identify and characterize biogeographical regions, based on a large database containing 2.5 million of geolocalized plant records corresponding to more than 3,500 plant species. This methodology is performed following five steps, from the biogeographical bipartite network construction to the identification of biogeographical regions under the form of spatial network communities, the analysis of their interactions, and the identification of clusters of plant species based on the species contribution to the biogeographical regions. First, we identified two sub‐networks that distinguish Mediterranean and temperate biota. Then, we separated eight statistically significant bioregions that present a complex spatial structure. Some of them are spatially well delimited and match with particular geological entities. On the other hand, fuzzy transitions arise between adjacent bioregions that share a common geological setting, but are spread along a climatic gradient. The proposed network approach illustrates the biogeographical structure of the flora in southern France and provides precise insights into the relationships between bioregions. This approach sheds light on ecological drivers shaping the distribution of Mediterranean biota: The interplay between a climatic gradient and geological substrate shapes biodiversity patterns. Finally, this work exemplifies why fragmented distributions are common in the Mediterranean region, isolating groups of species that share a similar eco‐evolutionary history. 相似文献
112.
Maxime Bruto Claire Prigent-Combaret Patricia Luis Yvan Mo?nne-Loccoz Daniel Muller 《Proceedings. Biological sciences / The Royal Society》2014,281(1789)
Even genetically distant prokaryotes can exchange genes between them, and these horizontal gene transfer events play a central role in adaptation and evolution. While this was long thought to be restricted to prokaryotes, certain eukaryotes have acquired genes of bacterial origin. However, gene acquisitions in eukaryotes are thought to be much less important in magnitude than in prokaryotes. Here, we describe the complex evolutionary history of a bacterial catabolic gene that has been transferred repeatedly from different bacterial phyla to stramenopiles and fungi. Indeed, phylogenomic analysis pointed to multiple acquisitions of the gene in these filamentous eukaryotes—as many as 15 different events for 65 microeukaryotes. Furthermore, once transferred, this gene acquired introns and was found expressed in mRNA databases for most recipients. Our results show that effective inter-domain transfers and subsequent adaptation of a prokaryotic gene in eukaryotic cells can happen at an unprecedented magnitude. 相似文献
113.
Nina Bertaux-Skeirik Rui Feng Michael A. Schumacher Jing Li Maxime M. Mahe Amy C. Engevik Jose E. Javier Richard M. Peek Jr Karen Ottemann Veronique Orian-Rousseau Gregory P. Boivin Michael A. Helmrath Yana Zavros 《PLoS pathogens》2015,11(2)
The cytotoxin-associated gene (Cag) pathogenicity island is a strain-specific
constituent of Helicobacter pylori (H. pylori) that
augments cancer risk. CagA translocates into the cytoplasm where it stimulates cell
signaling through the interaction with tyrosine kinase c-Met receptor, leading
cellular proliferation. Identified as a potential gastric stem cell marker,
cluster-of-differentiation (CD) CD44 also acts as a co-receptor for c-Met, but
whether it plays a functional role in H. pylori-induced epithelial
proliferation is unknown. We tested the hypothesis that CD44 plays a functional role
in H. pylori-induced epithelial cell proliferation. To assay changes
in gastric epithelial cell proliferation in relation to the direct interaction with
H. pylori, human- and mouse-derived gastric organoids were
infected with the G27 H. pylori strain or a mutant G27 strain
bearing cagA deletion (∆CagA::cat). Epithelial proliferation
was quantified by EdU immunostaining. Phosphorylation of c-Met was analyzed by
immunoprecipitation followed by Western blot analysis for expression of CD44 and
CagA. H. pylori infection of both mouse- and human-derived gastric
organoids induced epithelial proliferation that correlated with c-Met
phosphorylation. CagA and CD44 co-immunoprecipitated with phosphorylated c-Met. The
formation of this complex did not occur in organoids infected with
∆CagA::cat. Epithelial proliferation in response to
H. pylori infection was lost in infected organoids derived from
CD44-deficient mouse stomachs. Human-derived fundic gastric organoids exhibited an
induction in proliferation when infected with H. pylorithat was not
seen in organoids pre-treated with a peptide inhibitor specific to CD44. In the
well-established Mongolian gerbil model of gastric cancer, animals treated with CD44
peptide inhibitor Pep1, resulted in the inhibition of H.
pylori-induced proliferation and associated atrophic gastritis. The current
study reports a unique approach to study H. pylori interaction with
the human gastric epithelium. Here, we show that CD44 plays a functional role in
H. pylori-induced epithelial cell proliferation. 相似文献
114.
Camille V. Chagneau Clmence Massip Nadge Bossuet-Greif Christophe Fremez Jean-Paul Motta Ayaka Shima Cline Besson Pauline Le Faouder Nicolas Cnac Marie-Paule Roth Hlne Coppin Maxime Fontani Patricia Martin Jean-Philippe Nougayrde Eric Oswald 《PLoS pathogens》2021,17(2)
Urinary tract infections (UTIs) are among the most common outpatient infections, with a lifetime incidence of around 60% in women. We analysed urine samples from 223 patients with community-acquired UTIs and report the presence of the cleavage product released during the synthesis of colibactin, a bacterial genotoxin, in 55 of the samples examined. Uropathogenic Escherichia coli strains isolated from these patients, as well as the archetypal E. coli strain UTI89, were found to produce colibactin. In a murine model of UTI, the machinery producing colibactin was expressed during the early hours of the infection, when intracellular bacterial communities form. We observed extensive DNA damage both in umbrella and bladder progenitor cells. To the best of our knowledge this is the first report of colibactin production in UTIs in humans and its genotoxicity in bladder cells. 相似文献
115.
Sylvain Boisson Maxime Séleck Soizig Le Stradic Julien Collignon Olivier Garin François Malaisse Mylor Ngoy Shutcha Grégory Mahy 《Ecological Research》2018,33(4):789-798
Outcrops in the southeastern Democratic Republic of the Congo (DRC) are recognized as some of the largest copper–cobalt orebodies in the world. They support a unique vegetation with nearly 600 metallophytes that include rare and endemic species. Mineral exploitation has increased considerably in the region since the 1900s, affecting both environmental and public health. Phytostabilisation of polluted areas represents an opportunity to decrease the bioavailability of heavy metals in the highly polluted soils that result from ore extraction. Such a technique has been successfully implemented near Lubumbashi with the grass Microchloa altera. However, long-term maintenance requires a good understanding of interspecific relationships, such as competition and facilitation. This study tested the establishment success of four herbaceous species from the Katangan Copperbelt by assessing the potential role of Microchloa altera as a nurse species. Two annual and two perennial species were sown in an experiment designed to study the influence of soil amendment and vegetation cover on seedling emergence, growth, and survival. These variables were monitored during the vegetation growing season as well as resprouting success for perennials. Microchloa altera showed a distinct effect on the emergence and survival of annual and perennial species and negatively affected the growth of individuals belonging to both groups of species. 相似文献
116.
Tong Liu Jian Zhao Cristian Ibarra Maxime U. Garcia Per Uhlén Monica Nistér 《European journal of cell biology》2018,97(3):190-203
The Na+/Ca2+ exchanger (NCX) is a membrane antiporter that has been identified in the plasma membrane, the inner membrane of the nuclear envelope and in the membrane of the endoplasmic reticulum (ER). In humans, three genes have been identified, encoding unique NCX proteins. Although extensively studied, the NCX’s sub-cellular localization and mechanisms regulating the activity of different subtypes are still ambiguous. Here we investigated the subcellular localization of the NCX subtype 3 (NCX3) and its impact on the cell cycle. Two phenotypes, switching from one to the other during the cell cycle, were detected. One phenotype was NCX3 in the plasma membrane during S and M phase, and the other was NCX3 in the ER membrane during resting and interphase. Glycosylation of NCX3 at the N45 site was required for targeting the protein to the plasma membrane, and the N45 site functioned as an on-off switch for the translocation of NCX3 to either the plasma membrane or the membrane of the ER. Introduction of an N-glycosylation deficient NCX3 mutant led to an arrest of cells in the G0/G1 phase of the cell cycle. This was accompanied by accumulation of de-glycosylated NCX3 in the cytosol (that is in the ER), where it transported calcium ions (Ca2+) from the cytosol to the ER. These results, obtained in transfected HEK293T and HeLa and confirmed endogenously in SH-SY5Y cells, suggest that cells can use a dynamic Ca2+ signaling toolkit in which the NCX3 sub-cellular localization changes in synchrony with the cell cycle. 相似文献
117.
Carrier Transport and Recombination in Efficient “All‐Small‐Molecule” Solar Cells with the Nonfullerene Acceptor IDTBR 下载免费PDF全文
Ru‐Ze Liang Maxime Babics Victoria Savikhin Weimin Zhang Vincent M. Le Corre Sergei Lopatin Zhipeng Kan Yuliar Firdaus Shengjian Liu Iain McCulloch Michael F. Toney Pierre M. Beaujuge 《Liver Transplantation》2018,8(19)
Reaching device efficiencies that can rival those of polymer‐fullerene Bulk Heterojunction (BHJ) solar cells (>10%) remains challenging with the “All‐Small‐Molecule” (All‐SM) approach, in part because of (i) the morphological limitations that prevail in the absence of polymer and (ii) the difficulty to raise and balance out carrier mobilities across the active layer. In this report, the authors show that blends of the SM donor DR3TBDTT (DR3) and the nonfullerene SM acceptor O‐IDTBR are conducive to “All‐SM” BHJ solar cells with high open‐circuit voltages (VOC) >1.1 V and PCEs as high as 6.4% (avg. 6.1%) when the active layers are subjected to a post‐processing solvent vapor‐annealing (SVA) step with dimethyl disulfide (DMDS). Combining electron energy loss spectroscopy (EELS) analyses and systematic carrier recombination examinations, the authors show that SVA treatments with DMDS play a determining role in improving charge transport and reducing non‐geminate recombination for the DR3:O‐IDTBR system. Correlating the experimental results and device simulations, it is found that substantially higher BHJ solar cell efficiencies of >12% can be achieved if the IQE and carrier mobilities of the active layer are increased to >85% and >10?4 cm2 V?1 s?1, respectively, while suppressing the recombination rate constant k to <10?12 cm3 s?1. 相似文献
118.
119.
Alice L. Mauchline Maxime R. Hervé Samantha M. Cook 《Arthropod-Plant Interactions》2018,12(6):835-847
There is an urgent need to develop sustainable pest management systems to protect arable crops in order to replace the current over-reliance on synthetic insecticides. Semiochemicals are insect- or plant-derived chemicals that are used by organisms as information signals. Integrated pest management tools are currently in development that utilise semiochemicals to manipulate the behaviour of pest insects and their natural enemies to provide effective control of pests within the crop. These innovative tools usually require fewer inputs and can involve multiple elements, therefore reducing the likelihood of resistance developing compared with use of synthetic toxicants. We review here the life cycle of the pollen beetle Brassicogethes aeneus (previously known as Meligethes aeneus) which is a pest insect of oilseed rape (Brassica napus) and describe the current knowledge of any behaviour mediated by semiochemicals in this species. We discuss the behavioural processes where semiochemical-based control approaches may be appropriate and consider how these approaches could be incorporated into an integrated pest management strategy for this important arable crop. 相似文献
120.
Jean-Claude Brouet Jean-Louis Preud'homme Maxime Seligmann Jean Bernard 《BMJ (Clinical research ed.)》1973,4(5883):23-24
Acute blast crisis occurred in two patients with previously well-confirmed chronic lymphocytic leukaemia. The finding by direct immunofluorescence of membrane-bound monoclonal immunoglobulins on the surface of the blast cells showed that they were related to B cells in the same way as the proliferating lymphocytes in most patients with chronic lymphocytic leukaemia. In one patient the surface monoclonal IgM detected on both the lymphocytes and the blast cells had the same rheumatoid antibody activity, supporting the concept that the leukaemic cells found during the acute and chronic phases of the disease originated from the same clone. 相似文献