全文获取类型
收费全文 | 1140篇 |
免费 | 98篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 31篇 |
2020年 | 12篇 |
2019年 | 24篇 |
2018年 | 27篇 |
2017年 | 23篇 |
2016年 | 53篇 |
2015年 | 72篇 |
2014年 | 70篇 |
2013年 | 74篇 |
2012年 | 128篇 |
2011年 | 93篇 |
2010年 | 66篇 |
2009年 | 51篇 |
2008年 | 70篇 |
2007年 | 63篇 |
2006年 | 48篇 |
2005年 | 53篇 |
2004年 | 55篇 |
2003年 | 38篇 |
2002年 | 43篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 11篇 |
1995年 | 7篇 |
1994年 | 18篇 |
1993年 | 7篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1985年 | 4篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 7篇 |
1979年 | 2篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有1238条查询结果,搜索用时 31 毫秒
21.
22.
Li Wang Tian-Cai Niu Ana Valladares Gui-Ming Lin Ju-Yuan Zhang Antonia Herrero Wen-Li Chen Cheng-Cai Zhang 《Environmental microbiology》2021,23(8):4823-4837
FtsZ is a tubulin-like GTPase that polymerizes to initiate the process of cell division in bacteria. Heterocysts are terminally differentiated cells of filamentous cyanobacteria that have lost the capacity for cell division and in which the ftsZ gene is downregulated. However, mechanisms of FtsZ regulation during heterocyst differentiation have been scarcely investigated. The patD gene is NtcA dependent and involved in the optimization of heterocyst frequency in Anabaena sp. PCC 7120. Here, we report that the inactivation of patD caused the formation of multiple FtsZ-rings in vegetative cells, cell enlargement, and the retention of peptidoglycan synthesis activity in heterocysts, whereas its ectopic expression resulted in aberrant FtsZ polymerization and cell division. PatD interacted with FtsZ, increased FtsZ precipitation in sedimentation assays, and promoted the formation of thick straight FtsZ bundles that differ from the toroidal aggregates formed by FtsZ alone. These results suggest that in the differentiating heterocysts, PatD interferes with the assembly of FtsZ. We propose that in Anabaena FtsZ is a bifunctional protein involved in both vegetative cell division and regulation of heterocyst differentiation. In the differentiating cells PatD-FtsZ interactions appear to set an FtsZ activity that is insufficient for cell division but optimal to foster differentiation. 相似文献
23.
Antonia P. De Los Ríos Francisco J. Hernández-Fernández Francisco A. Martínez Manuel Rubio Gloria Víllora 《Biocatalysis and Biotransformation》2013,31(2-4):151-156
Nineteen different 1,3-dialkylimidazolium-based ionic liquids (ILs) were used as reaction media for the synthesis of butyl butyrate by transesterification from vinyl butyrate and 1-butanol catalyzed by Candida antarctica lipase B (CaLB). The reaction was also carried out in hexane as a reference solvent. In all the water-immiscible ILs assayed, the enzymatic activity and selectivity were higher than that obtained in hexane. However, in water-miscible ILs, the activity was lower than in the reference solvent, although they showed >99.99% selectivity. Two solvent properties, hydrophobicity and nucleophilicity, were considered key parameters for analyzing the behavior of CaLB in ILs. In the case of ILs based on the same anion, the synthetic activity was gradually enhanced by increasing cation hydrophobicity. Furthermore, the activity of CaLB was greater in ILs containing anions of lower nucleophilicity. Stability studies indicate that CaLB exhibited greater stability in water-immiscible ILs than in water-miscible ILs. 相似文献
24.
J. Ross Chapman Patricia Barral Jean-Baptiste Vannier Valérie Borel Martin Steger Antonia Tomas-Loba Alessandro A. Sartori Ian R. Adams Facundo D. Batista Simon J. Boulton 《Molecular cell》2013,49(5):858-871
- Download : Download high-res image (298KB)
- Download : Download full-size image
25.
Manousos Makridakis Maria G. Roubelakis Antonia Vlahou 《Biochimica et Biophysica Acta - Proteins and Proteomics》2013,1834(11):2380-2384
Stem cells have been considered as possible therapeutic vehicles for different health related problems such as cardiovascular and neurodegenerative diseases and cancer. Secreted molecules are key mediators in cell–cell interactions and influence the cross talk with the surrounding tissues. There is strong evidence supporting that crucial cellular functions such as proliferation, differentiation, communication and migration are strictly regulated from the cell secretome. The investigation of stem cell secretome is accumulating continuously increasing interest given the potential use of these cells in regenerative medicine. The scope of the review is to report the main findings from the investigation of stem cell secretome by the use of contemporary proteomics methods and discuss the current status of research in the field. This article is part of a Special Issue entitled: An Updated Secretome. 相似文献
26.
Antonia P. Popova 《Journal of cell communication and signaling》2013,7(2):119-127
Bronchopulmonary dysplasia (BPD) is a chronic lung disease affecting premature infants with long term effect on lung function into adulthood. Multiple factors are involved in the development of BPD. This review will summarize the different mechanisms leading to this disease and highlight recent bench and clinical research targeted at understanding the role of the mesenchyme (both its cellular and extracellular components) in the pathogenesis of BPD. 相似文献
27.
Reyes Babiano Gwenael Badis Cosmin Saveanu Abdelkader Namane Antonia Doyen Antonio Díaz-Quintana Alain Jacquier Micheline Fromont-Racine Jesús de la Cruz 《Nucleic acids research》2013,41(20):9461-9470
Ribosome biogenesis requires >300 assembly factors in Saccharomyces cerevisiae. Ribosome assembly factors Imp3, Mrt4, Rlp7 and Rlp24 have sequence similarity to ribosomal proteins S9, P0, L7 and L24, suggesting that these pre-ribosomal factors could be placeholders that prevent premature assembly of the corresponding ribosomal proteins to nascent ribosomes. However, we found L7 to be a highly specific component of Rlp7-associated complexes, revealing that the two proteins can bind simultaneously to pre-ribosomal particles. Cross-linking and cDNA analysis experiments showed that Rlp7 binds to the ITS2 region of 27S pre-rRNAs, at two sites, in helix III and in a region adjacent to the pre-rRNA processing sites C1 and E. However, L7 binds to mature 25S and 5S rRNAs and cross-linked predominantly to helix ES7Lb within 25S rRNA. Thus, despite their predicted structural similarity, our data show that Rlp7 and L7 clearly bind at different positions on the same pre-60S particles. Our results also suggest that Rlp7 facilitates the formation of the hairpin structure of ITS2 during 60S ribosomal subunit maturation. 相似文献
28.
Amanda C. Fortes Antonia Amanda C. Almeida Francisco Jaime B. Mendonça-Júnior Rivelilson M. Freitas José Lamartine Soares-Sobrinho Monica Felts de La Roca Soares 《Neurochemical research》2013,38(4):726-731
2-[(2,6-dichlorobenzylidene)amino]-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile), 5TIO1, is a new 2-aminothiophene derivative with a promising pharmacological activity. The aim of this work was to evaluate the potential anxiolytic effect of 5TIO1 in animal models. In the elevated plus-maze test, 5TIO1 (0.1, 1.0 and 10.0 mg/kg, i.p) increased the time of permanence and the number of entries in the open arms. In the light/dark box test, 5TIO1 at dose of 0.1 mg/kg (i.p) also showed anxiolytic-like effect indicated by an increase in the time spent in the light box, similar to diazepam 2.0 mg/kg (i.p). 5TIO1 groups did not change locomotor and coordination activities in open field and rotarod tests, respectively, when compared to vehicle. Dose dependent process was not observed and the anxiolytic effects demonstrated were not completely reversed by flumazenil 25 mg/kg (i.p). Our results suggest that 5TIO1 can bind with other receptors, besides the benzodiazepine site of the GABA receptor in mouse brain. 相似文献
29.