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Megan R. Underhill 《Ethnic and racial studies》2018,41(11):1934-1951
This paper examines what white, middle-class parents report saying to their children about racial tension and racial protest when events like Michael Brown’s death and the Ferguson protests are the top news stories. The data come from interviews with forty white, middle-class parents in 2014–15. The study results indicate that few parents recalled speaking with their children about racial tension or racial protest even when such discussions were highly visible in the news and on social media. I argue parents’ silence stemmed from a desire to create a protected, worry-free childhood combined with an inability to understand how such subjects related to their white life. However, not all parents were silent. Twelve participants reported speaking with their children about these subjects via a neutral or a defensive colour-blind frame. Only two participants drew attention to issues of power and privilege. 相似文献
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The use of the computer metaphor has led to the proposal of mind architecture (Pylyshyn 1984; Newell 1990) as a model of the organization of the mind. The dualist computational model, however, has, since the earliest days of psychological functionalism, required that the concepts mind architecture and brain architecture be remote from each other. The development of both connectionism and neurocomputational science, has sought to dispense with this dualism and provide general models of consciousness – a uniform cognitive architecture –, which is in general reductionist, but which retains the computer metaphor. This paper examines, in the first place, the concepts of mind architecture and brain architecture, in order to evaluate the syntheses which have recently been offered. It then moves on to show how modifications which have been made to classical functionalist mind architectures, with the aim of making them compatible with brain architectures, are unable to resolve some of the most serious problems of functionalism. Some suggestions are given as to why it is not possible to relate mind structures and brain structures by using neurocomputational approaches, and finally the question is raised of the validity of reductionism in a theory which sets out to unite mind and brain architectures. 相似文献
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S. LUYSSAERT I. INGLIMA M. JUNG A. D. RICHARDSON M. REICHSTEIN D. PAPALE S. L. PIAO E. ‐D. SCHULZE L. WINGATE G. MATTEUCCI L. ARAGAO M. AUBINET C. BEER C. BERNHOFER K. G. BLACK D. BONAL J. ‐M. BONNEFOND J. CHAMBERS P. CIAIS B. COOK K. J. DAVIS A. J. DOLMAN B. GIELEN M. GOULDEN J. GRACE A. GRANIER A. GRELLE T. GRIFFIS T. GRÜNWALD G. GUIDOLOTTI P. J. HANSON R. HARDING D. Y. HOLLINGER L. R. HUTYRA P. KOLARI B. KRUIJT W. KUTSCH F. LAGERGREN T. LAURILA B. E. LAW G. LE MAIRE A. LINDROTH D. LOUSTAU Y. MALHI J. MATEUS M. MIGLIAVACCA L. MISSON L. MONTAGNANI J. MONCRIEFF E. MOORS J. W. MUNGER E. NIKINMAA S. V. OLLINGER G. PITA C. REBMANN O. ROUPSARD N. SAIGUSA M. J. SANZ G. SEUFERT C. SIERRA M. ‐L. SMITH J. TANG R. VALENTINI T. VESALA I. A. JANSSENS 《Global Change Biology》2007,13(12):2509-2537
Terrestrial ecosystems sequester 2.1 Pg of atmospheric carbon annually. A large amount of the terrestrial sink is realized by forests. However, considerable uncertainties remain regarding the fate of this carbon over both short and long timescales. Relevant data to address these uncertainties are being collected at many sites around the world, but syntheses of these data are still sparse. To facilitate future synthesis activities, we have assembled a comprehensive global database for forest ecosystems, which includes carbon budget variables (fluxes and stocks), ecosystem traits (e.g. leaf area index, age), as well as ancillary site information such as management regime, climate, and soil characteristics. This publicly available database can be used to quantify global, regional or biome‐specific carbon budgets; to re‐examine established relationships; to test emerging hypotheses about ecosystem functioning [e.g. a constant net ecosystem production (NEP) to gross primary production (GPP) ratio]; and as benchmarks for model evaluations. In this paper, we present the first analysis of this database. We discuss the climatic influences on GPP, net primary production (NPP) and NEP and present the CO2 balances for boreal, temperate, and tropical forest biomes based on micrometeorological, ecophysiological, and biometric flux and inventory estimates. Globally, GPP of forests benefited from higher temperatures and precipitation whereas NPP saturated above either a threshold of 1500 mm precipitation or a mean annual temperature of 10 °C. The global pattern in NEP was insensitive to climate and is hypothesized to be mainly determined by nonclimatic conditions such as successional stage, management, site history, and site disturbance. In all biomes, closing the CO2 balance required the introduction of substantial biome‐specific closure terms. Nonclosure was taken as an indication that respiratory processes, advection, and non‐CO2 carbon fluxes are not presently being adequately accounted for. 相似文献
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We have isolated and characterized cDNA clones encoding the murine homologue of a putative fourth Na,K-ATPase alpha subunit isoform (alpha4). The predicted polypeptide is 1032 amino acids in length and exhibits 75% amino acid sequence identity to the rat alpha1, alpha2, and alpha3 subunits. Within the first extracellular loop, the alpha4 subunit is highly divergent from other Na,K-ATPase alpha subunits. Because this region of Na,K-ATPase is a major determinant of ouabain sensitivity, we tested the ability of the rodent alpha4 subunit to transfer ouabain resistance in a transfection protocol. We find that a cDNA containing the complete rodent alpha4 ORF is capable of conferring low levels of ouabain resistance upon HEK 293 cells, an indication that the alpha4 subunit can substitute for the endogenous ouabain-sensitive alpha subunit of human cells. Nucleotide sequences specific for the murine alpha4 subunit were used to identify the chromosomal position of the alpha4 subunit gene. By hybridizing an alpha4 probe with a series of BACs, we localized the alpha4 subunit gene (Atp1a4) to the distal portion of mouse chromosome 1, in very close proximity to the murine Na,K-ATPase alpha2 subunit gene. In adult mouse tissues, we detected expression of the alpha4 subunit gene almost exclusively in testis, with low levels of expression in epididymis. The close similarities in the organization and expression pattern of the murine and human alpha4 subunit genes suggest that these two genes are orthologous. Together, our studies indicate that the alpha4 subunit represents a functional Na,K-ATPase alpha subunit isoform. 相似文献
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