全文获取类型
收费全文 | 173篇 |
免费 | 4篇 |
专业分类
系统科学 | 6篇 |
丛书文集 | 2篇 |
理论与方法论 | 3篇 |
现状及发展 | 56篇 |
研究方法 | 37篇 |
综合类 | 63篇 |
自然研究 | 10篇 |
出版年
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 7篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 2篇 |
2014年 | 5篇 |
2013年 | 7篇 |
2012年 | 13篇 |
2011年 | 23篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 12篇 |
2005年 | 7篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2000年 | 2篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1986年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1968年 | 5篇 |
1967年 | 1篇 |
1966年 | 3篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1945年 | 1篇 |
排序方式: 共有177条查询结果,搜索用时 15 毫秒
91.
F. Joó 《Cellular and molecular life sciences : CMLS》1963,19(8):415-416
Summary By means of polarization microscope, the submicroscopic structure of intercalated discs in auricle and ventricle muscles of rat heart were investigated using an imbibition method and precipitation anisotropic staining. The investigation proved that the protein and lipid parts in intercalated discs of auricle muscles are, on the contrary, arranged like intercalated discs of ventricle muscles.The ultrastructural variance revealed can be explained by mechanical effects exerted by the myofibrils on the plasma membranes which separate the adjacent heart muscle cells. 相似文献
92.
93.
Resumen Se investigaron los efectos del stress y la obesidad en diversos mecanismos fisiológicos hipotalámicos. La obesidad fué evidente inyectando aurothioglucose. Estadisticamente se registraron mayores aumentos en ratones aislados que en aquellos mantenidos familiarmente. 相似文献
94.
F. Joó 《Cellular and molecular life sciences : CMLS》1972,28(12):1470-1471
Zusammenfassung Die Anzahl der pinocytotischen und stachligen Vesicula wurde unter normalen Bedingungen mit Bezug auf einheitliche Gebiete der pinocytotischen Aktivität der Kapillaren von Mäusegehirnen quantitativ charakterisiert. Die Pinocytose der Gehirnkapillaren war durch das substitutielle cyclische N6O2-Dibutyrylderivat des 3,5-Adenosinmonophosphats signifikant gesteigert. 相似文献
95.
Giraud E Fardoux J Fourrier N Hannibal L Genty B Bouyer P Dreyfus B Verméglio A 《Nature》2002,417(6885):202-205
Plants use a set of light sensors to control their growth and development in response to changes in ambient light. In particular, phytochromes exert their regulatory activity by switching between a biologically inactive red-light-absorbing form (Pr) and an active far-red-light absorbing form (Pfr). Recently, biochemical and genetic studies have demonstrated the occurrence of phytochrome-like proteins in photosynthetic and non-photosynthetic bacteria--but little is known about their functions. Here we report the discovery of a bacteriophytochrome located downstream from the photosynthesis gene cluster in a Bradyrhizobium strain symbiont of Aeschynomene. The synthesis of the complete photosynthetic apparatus is totally under the control of this bacteriophytochrome. A similar behaviour is observed for the closely related species Rhodopseudomonas palustris, but not for the more distant anoxygenic photosynthetic bacteria of the genus Rhodobacter, Rubrivivax or Rhodospirillum. Unlike other (bacterio)phytochromes, the carboxy-terminal domain of this bacteriophytochrome contains no histidine kinase features. This suggests a light signalling pathway involving direct protein-protein interaction with no phosphorelay cascade. This specific mechanism of regulation may represent an important ecological adaptation to optimize the plant-bacteria interaction. 相似文献
96.
97.
98.
Holzenberger M Dupont J Ducos B Leneuve P Géloën A Even PC Cervera P Le Bouc Y 《Nature》2003,421(6919):182-187
Studies in invertebrates have led to the identification of a number of genes that regulate lifespan, some of which encode components of the insulin or insulin-like signalling pathways. Examples include the related tyrosine kinase receptors InR (Drosophila melanogaster) and DAF-2 (Caenorhabditis elegans) that are homologues of the mammalian insulin-like growth factor type 1 receptor (IGF-1R). To investigate whether IGF-1R also controls longevity in mammals, we inactivated the IGF-1R gene in mice (Igf1r). Here, using heterozygous knockout mice because null mutants are not viable, we report that Igf1r(+/-) mice live on average 26% longer than their wild-type littermates (P < 0.02). Female Igf1r(+/-) mice live 33% longer than wild-type females (P < 0.001), whereas the equivalent male mice show an increase in lifespan of 16%, which is not statistically significant. Long-lived Igf1r(+/-) mice do not develop dwarfism, their energy metabolism is normal, and their nutrient uptake, physical activity, fertility and reproduction are unaffected. The Igf1r(+/-) mice display greater resistance to oxidative stress, a known determinant of ageing. These results indicate that the IGF-1 receptor may be a central regulator of mammalian lifespan. 相似文献
99.
Verjovski-Almeida S DeMarco R Martins EA Guimarães PE Ojopi EP Paquola AC Piazza JP Nishiyama MY Kitajima JP Adamson RE Ashton PD Bonaldo MF Coulson PS Dillon GP Farias LP Gregorio SP Ho PL Leite RA Malaquias LC Marques RC Miyasato PA Nascimento AL Ohlweiler FP Reis EM Ribeiro MA Sá RG Stukart GC Soares MB Gargioni C Kawano T Rodrigues V Madeira AM Wilson RA Menck CF Setubal JC Leite LC Dias-Neto E 《Nature genetics》2003,35(2):148-157
Schistosoma mansoni is the primary causative agent of schistosomiasis, which affects 200 million individuals in 74 countries. We generated 163,000 expressed-sequence tags (ESTs) from normalized cDNA libraries from six selected developmental stages of the parasite, resulting in 31,000 assembled sequences and 92% sampling of an estimated 14,000 gene complement. By analyzing automated Gene Ontology assignments, we provide a detailed view of important S. mansoni biological systems, including characterization of metazoa-specific and eukarya-conserved genes. Phylogenetic analysis suggests an early divergence from other metazoa. The data set provides insights into the molecular mechanisms of tissue organization, development, signaling, sexual dimorphism, host interactions and immune evasion and identifies novel proteins to be investigated as vaccine candidates and potential drug targets. 相似文献
100.
Sarah De Clercq Olivier Zwaenepoel Evelien Martens Joël Vandekerckhove Aude Guillabert Jan Gettemans 《Cellular and molecular life sciences : CMLS》2013,70(5):909-922
The T cell integrin receptor LFA-1 orchestrates adhesion between T cells and antigen-presenting cells (APCs), resulting in formation of a contact zone known as the immune synapse (IS) which is supported by the cytoskeleton. L-plastin is a leukocyte-specific actin bundling protein that rapidly redistributes to the immune synapse following T cell–APC engagement. We used single domain antibodies (nanobodies, derived from camelid heavy-chain only antibodies) directed against functional and structural modules of L-plastin to investigate its contribution to formation of an immune synapse between Raji cells and human peripheral blood mononuclear cells or Jurkat T cells. Nanobodies that interact either with the EF hands or the actin binding domains of L-plastin both trapped L-plastin in an inactive conformation, causing perturbation of IS formation, MTOC docking towards the plasma membrane, T cell proliferation and IL-2 secretion. Both nanobodies delayed Ser5 phosphorylation of L-plastin which is required for enhanced bundling activity. Moreover, one nanobody delayed LFA-1 phosphorylation, reduced the association between LFA-1 and L-plastin and prevented LFA-1 enrichment at the IS. Our findings reveal subtle mechanistic details that are difficult to attain by conventional means and show that L-plastin contributes to immune synapse formation at distinct echelons. 相似文献