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141.
Quantitative analysis is increasingly being used in team sports to better understand performance in these stylized, delineated, complex social systems. Here, the authors provide a first step toward understanding the pattern-forming dynamics that emerge from collective offensive and defensive behavior in team sports. The authors propose a novel method of analysis that captures how teams occupy sub-areas of the field as the ball changes location. The authors use this method to analyze a game of association football (soccer) based upon a hypothesis that local player numerical dominance is key to defensive stability and offensive opportunity. The authors find that the teams consistently allocated more players than their opponents in sub-areas of play closer to their own goal. This is consistent with a predominantly defensive strategy intended to prevent yielding even a single goal. The authors also find differences between the two teams’ strategies: while both adopted the same distribution of defensive, midfield, and attacking players (a 4: 3: 3 system of play), one team was significantly more effective in maintaining both defensive and offensive numerical dominance for defensive stability and offensive opportunity. That team indeed won the match with an advantage of one goal (2 to 1) but the analysis shows the advantage in play was more pervasive than the single goal victory would indicate. The proposed focus on the local dynamics of team collective behavior is distinct from the traditional focus on individual player capability. It supports a broader view in which specific player abilities contribute within the context of the dynamics of multiplayer team coordination and coaching strategy. By applying this complex system analysis to association football, the authors can understand how players’ and teams’ strategies result in successful and unsuccessful relationships between teammates and opponents in the area of play. 相似文献
142.
The eastern woodrat ( Neotoma floridana ) occurs throughout eastern and central parts of the United States. In Nebraska, 3 of 9 subspecies inhabit the state, including N. f. campestris , N. f. attwateri , and N. f. baileyi . We determined distributional limits of N. f. campestris along 2 river systems in southern Nebraska. As observed with other mammalian species in the Great Plains, we suspected that the distribution of woodrats likely had expanded, reflecting continued regulation of rivers and the concomitant increase in forests along them. We documented N. f. campestris at 7 sites in 5 counties, including a recent (since the 1960s) eastward expansion along the Republican River. We observed little movement along the Platte River. The greatest concentration of houses constructed by woodrats occurred in a shelterbelt near the Republican River; otherwise, abundances of houses tended to be greater along the Platte River. We suspect that the distribution of woodrats will continue to change in Nebraska unless breaks exist or are established in riparian forests along the Platte and Republican rivers. 相似文献
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Martin MP Gao X Lee JH Nelson GW Detels R Goedert JJ Buchbinder S Hoots K Vlahov D Trowsdale J Wilson M O'Brien SJ Carrington M 《Nature genetics》2002,31(4):429-434
Natural killer (NK) cells provide defense in the early stages of the innate immune response against viral infections by producing cytokines and causing cytotoxicity. The killer immunoglobulin-like receptors (KIRs) on NK cells regulate the inhibition and activation of NK-cell responses through recognition of human leukocyte antigen (HLA) class I molecules on target cells KIR and HLA loci are both highly polymorphic, and some HLA class I products bind and trigger cell-surface receptors specified by KIR genes. Here we report that the activating KIR allele KIR3DS1, in combination with HLA-B alleles that encode molecules with isoleucine at position 80 (HLA-B Bw4-80Ile), is associated with delayed progression to AIDS in individuals infected with human immunodeficiency virus type 1 (HIV-1). In the absence of KIR3DS1, the HLA-B Bw4-80Ile allele was not associated with any of the AIDS outcomes measured. By contrast, in the absence of HLA-B Bw4-80Ile alleles, KIR3DS1 was significantly associated with more rapid progression to AIDS. These observations are strongly suggestive of a model involving an epistatic interaction between the two loci. The strongest synergistic effect of these loci was on progression to depletion of CD4(+) T cells, which suggests that a protective response of NK cells involving KIR3DS1 and its HLA class I ligands begins soon after HIV-1 infection. 相似文献
148.
Vogelsang KM 《Nature》2002,420(6913):267
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Gardner MJ Hall N Fung E White O Berriman M Hyman RW Carlton JM Pain A Nelson KE Bowman S Paulsen IT James K Eisen JA Rutherford K Salzberg SL Craig A Kyes S Chan MS Nene V Shallom SJ Suh B Peterson J Angiuoli S Pertea M Allen J Selengut J Haft D Mather MW Vaidya AB Martin DM Fairlamb AH Fraunholz MJ Roos DS Ralph SA McFadden GI Cummings LM Subramanian GM Mungall C Venter JC Carucci DJ Hoffman SL Newbold C Davis RW Fraser CM Barrell B 《Nature》2002,419(6906):498-511
The parasite Plasmodium falciparum is responsible for hundreds of millions of cases of malaria, and kills more than one million African children annually. Here we report an analysis of the genome sequence of P. falciparum clone 3D7. The 23-megabase nuclear genome consists of 14 chromosomes, encodes about 5,300 genes, and is the most (A + T)-rich genome sequenced to date. Genes involved in antigenic variation are concentrated in the subtelomeric regions of the chromosomes. Compared to the genomes of free-living eukaryotic microbes, the genome of this intracellular parasite encodes fewer enzymes and transporters, but a large proportion of genes are devoted to immune evasion and host-parasite interactions. Many nuclear-encoded proteins are targeted to the apicoplast, an organelle involved in fatty-acid and isoprenoid metabolism. The genome sequence provides the foundation for future studies of this organism, and is being exploited in the search for new drugs and vaccines to fight malaria. 相似文献
150.
Zusammenfassung Es wird gezeigt, dass die Amylophagie bei der Maus keine Anämie, dagegen eine Verminderung der Graviditäten und Abnahme der pro Geburt geborenen Jungtiere herbeiführt. 相似文献