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91.
R. I. Henkin D. L. Gilbert I. Stillman R. DiPolo 《Cellular and molecular life sciences : CMLS》1973,29(5):555-556
Zusammenfassung Adrenocorticosteroide und Adrenocorticotropin bewirkten in hohen Konzentrationen keine Änderungen der Na–K Ströme in Tintenfischriesenaxon; das weist darauf hin, dass die Ionenbegebenheiten, die das Axenpotential hervorrufen, durch diese Hormone nicht beeinflusst sind. 相似文献
92.
Pleistocene Homo sapiens from Middle Awash,Ethiopia 总被引:10,自引:0,他引:10
The origin of anatomically modern Homo sapiens and the fate of Neanderthals have been fundamental questions in human evolutionary studies for over a century. A key barrier to the resolution of these questions has been the lack of substantial and accurately dated African hominid fossils from between 100,000 and 300,000 years ago. Here we describe fossilized hominid crania from Herto, Middle Awash, Ethiopia, that fill this gap and provide crucial evidence on the location, timing and contextual circumstances of the emergence of Homo sapiens. Radioisotopically dated to between 160,000 and 154,000 years ago, these new fossils predate classic Neanderthals and lack their derived features. The Herto hominids are morphologically and chronologically intermediate between archaic African fossils and later anatomically modern Late Pleistocene humans. They therefore represent the probable immediate ancestors of anatomically modern humans. Their anatomy and antiquity constitute strong evidence of modern-human emergence in Africa. 相似文献
93.
Mungall AJ Palmer SA Sims SK Edwards CA Ashurst JL Wilming L Jones MC Horton R Hunt SE Scott CE Gilbert JG Clamp ME Bethel G Milne S Ainscough R Almeida JP Ambrose KD Andrews TD Ashwell RI Babbage AK Bagguley CL Bailey J Banerjee R Barker DJ Barlow KF Bates K Beare DM Beasley H Beasley O Bird CP Blakey S Bray-Allen S Brook J Brown AJ Brown JY Burford DC Burrill W Burton J Carder C Carter NP Chapman JC Clark SY Clark G Clee CM Clegg S Cobley V Collier RE Collins JE Colman LK Corby NR Coville GJ 《Nature》2003,425(6960):805-811
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Sensory perception is a learned trait. The brain strategies we use to perceive the world are constantly modified by experience. With practice, we subconsciously become better at identifying familiar objects or distinguishing fine details in our environment. Current theoretical models simulate some properties of perceptual learning, but neglect the underlying cortical circuits. Future neural network models must incorporate the top-down alteration of cortical function by expectation or perceptual tasks. These newly found dynamic processes are challenging earlier views of static and feedforward processing of sensory information. 相似文献
96.
Impaired PtdIns(4,5)P2 synthesis in nerve terminals produces defects in synaptic vesicle trafficking
Di Paolo G Moskowitz HS Gipson K Wenk MR Voronov S Obayashi M Flavell R Fitzsimonds RM Ryan TA De Camilli P 《Nature》2004,431(7007):415-422
Phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2) has an important function in cell regulation both as a precursor of second messenger molecules and by means of its direct interactions with cytosolic and membrane proteins. Biochemical studies have suggested a role for PtdIns(4,5)P2 in clathrin coat dynamics, and defects in its dephosphorylation at the synapse produce an accumulation of coated endocytic intermediates. However, the involvement of PtdIns(4,5)P2 in synaptic vesicle exocytosis remains unclear. Here, we show that decreased levels of PtdIns(4,5)P2 in the brain and an impairment of its depolarization-dependent synthesis in nerve terminals lead to early postnatal lethality and synaptic defects in mice. These include decreased frequency of miniature currents, enhanced synaptic depression, a smaller readily releasable pool of vesicles, delayed endocytosis and slower recycling kinetics. Our results demonstrate a critical role for PtdIns(4,5)P2 synthesis in the regulation of multiple steps of the synaptic vesicle cycle. 相似文献
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Autism Genome Project Consortium Szatmari P Paterson AD Zwaigenbaum L Roberts W Brian J Liu XQ Vincent JB Skaug JL Thompson AP Senman L Feuk L Qian C Bryson SE Jones MB Marshall CR Scherer SW Vieland VJ Bartlett C Mangin LV Goedken R Segre A Pericak-Vance MA Cuccaro ML Gilbert JR Wright HH Abramson RK Betancur C Bourgeron T Gillberg C Leboyer M Buxbaum JD Davis KL Hollander E Silverman JM Hallmayer J Lotspeich L Sutcliffe JS Haines JL Folstein SE Piven J Wassink TH Sheffield V Geschwind DH 《Nature genetics》2007,39(3):319-328
Autism spectrum disorders (ASDs) are common, heritable neurodevelopmental conditions. The genetic architecture of ASDs is complex, requiring large samples to overcome heterogeneity. Here we broaden coverage and sample size relative to other studies of ASDs by using Affymetrix 10K SNP arrays and 1,181 [corrected] families with at least two affected individuals, performing the largest linkage scan to date while also analyzing copy number variation in these families. Linkage and copy number variation analyses implicate chromosome 11p12-p13 and neurexins, respectively, among other candidate loci. Neurexins team with previously implicated neuroligins for glutamatergic synaptogenesis, highlighting glutamate-related genes as promising candidates for contributing to ASDs. 相似文献
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