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251.
Aimed flexion movements of the arm of different amplitude and duration were studied. Velocity and acceleration traces of movements with equal duration but different amplitude were equal, apart from a scaling factor (ratio between movement amplitudes). After appropriate scaling, EMG activity of the first agonist burst for these movements superimposed. This was not true for EMG activity in the antagonist muscle. For movements with equal amplitude, but different duration, the time to peak acceleration was constant for all MT'. Except for this fact, traces of acceleration, velocity, and agonist activity following the time of peak acceleration were about equal after appropriate scaling in time and amplitude. The integral of EMG activity in the first agonist burst increased linearly with peak velocity. For the antagonist burst, the integrated EMG activity increased more than proportionally. During movements made as fast as possible, subjects used a different strategy by varying the duration of the accelerating phase for movements of different amplitude. Movement amplitude was achieved by adjusting the duration of the agonist burst and the onset time for the antagonist muscle. Amplitude of the antagonist burst was constant within a narrow range for movements of different amplitude. These results did not change when the inertial mass was doubled by loading the arm with an additional mass. 相似文献
252.
Maarten A. Hajer 《Knowledge, Technology, and Policy》1995,8(4):26-39
This article examines how “design rationality” could help remediate the controversy over environmental degradation. Drawing
on the case of designing sustainable forms of traffic management, it argues that this will only be effective to a limited
degree. “Policy conversation” does indeed take place but within a coalition of actions that pushes a particular set of solutions.
This facilitates due procedure but erodes political legitimacy, thus potentially reproducing an intractable controversy. The
article suggests a five-phase model of democratic control as an alternative.
He primarily works in the field of sociology of technology and environment. He is presently involved in a research project
on the social redefinition of mobility, analyzing the translation of sustainable development into new institutional arrangements. 相似文献
253.
For an arbitrary similarity type of Boolean Algebras with Operators we define a class ofSahlqvist identities. Sahlqvist identities have two important properties. First, a Sahlqvist identity is valid in a complex algebra if and only if the underlying relational atom structure satisfies a first-order condition which can be effectively read off from the syntactic form of the identity. Second, and as a consequence of the first property, Sahlqvist identities arecanonical, that is, their validity is preserved under taking canonical embedding algebras. Taken together, these properties imply that results about a Sahlqvist variety V van be obtained by reasoning in the elementary class of canonical structures of algebras in V.We give an example of this strategy in the variety of Cylindric Algebras: we show that an important identity calledHenkin's equation is equivalent to a simpler identity that uses only one variable. We give a conceptually simple proof by showing that the first-order correspondents of these two equations are equivalent over the class of cylindric atom structures.Presented byIstván Németi 相似文献
254.
Maarten Franssen 《Synthese》1994,101(2):249-272
Gauthier's argument for constrained maximization, presented inMorals by Agreement, is perfected by taking into account the possibility of accidental exploitation and discussing the limitations on the values of the parameters which measure the translucency of the actors. Gauthier's argument is nevertheless shown to be defective concerning the rationality of constrained maximization as a strategic choice. It can be argued that it applies only to a single actor entering a population of individuals who are themselves not rational actors but simple rule-followers. A proper analysis of the strategic choice situation involving two rational actors who confront each other shows that constrained maximization as the choice of both actors can only result under very demanding assumptions. 相似文献
255.
256.
Maarten A. Hogervorst Astrid M. L. Kappers Jan J. Koenderink 《Attention, perception & psychophysics》1997,59(8):1266-1279
Wemeasured thresholds for the monocular discrimination of rigidly and nonrigidly moving objects defined by motion parallax. The retinal projections of rigidly moving objects are subject to certain constraints. By applying smooth 2-D transformations to the projections of rigidly moving objects, we created stimuli in which these constraints were affected. Thresholds for (generic) nonrigid transformations that in theory can be detected from rigid ones by processing pairs of views depended not only on the extent to which the rigidity constraints were affected, but also on the structure and the movement of the simulated object. Nonrigid transformations under which every three successive views had a rigid interpretation were not discriminable from rigid transformations, except in cases where the distortions were very large. Under the rigidity assumption, this would mean that a large class of nonrigidly moving objects is erroneously perceived as rigidly moving. 相似文献
257.
Henk ter Heide 《Knowledge, Technology, and Policy》1992,5(2):29-44
This article examines the management and use of knowledge in a relatively complex planning and policy process, i.e., the preparation
and implementation of the Fourth Report on Physical Planning in the Netherlands. Attention is given to the organization of
this process; the manner in which research, policy design and plan negotiation were intertwined in the various phases of the
process; and the solutions developed for the problem of obtaining sufficient knowledge without losing the impetus essential
to policy-making. General conclusions are derived especially concerning the interrelationship between policy-making and the
accretion and depletion of knowledge stocks.
While his earlier publications were primarily concerned with the application of demographic research in spatial policy, he
has more recently shifted his attention to knowledge utilization problems in general. 相似文献
258.
Maarten J. van der Vlugt Menno R. Kruk Annemoon M. M. van Erp Reint H. Geuze 《Behavior research methods》1992,24(2):147-149
CAMERA is a system for collecting and editing ethological data. The hardware and software enable easy coding of complex behavioral interactions from video recordings. It is especially designed to improve accuracy, reliability, and training standards in coding behavior. The system also supports several basic analyses of collected data. CAMERA operates with both North American and European video signals. 相似文献
259.
260.
Solving publicly important issues asks for the development of socio-technical approaches, which demands collaboration between researchers with different perspectives, values, and interests. In these complex interdisciplinary collaborations, the course of communication is of utmost importance, including the moments when people, consciously or not, keep silent. In 2012, an interdisciplinary group of water management engineers and scientists collaborated to explore how the university's separate water management research fields could fit better in today's socio-technical trends. Studying the interactional process revealed that during the collaboration many issues were not said by various parties at various times. Results show that, in particular, engineers and scientists stayed silent to secure group performance, to keep disagreements from surfacing, and manage conflicts of interest in the bargaining process. Although silence served various interactional functions, it also shaped the course of interaction in ways that were not intended, resulting in the development of a latent conflict. It is concluded that the concept of silence adds a relevant dimension to our understanding of interaction among engineers and scientists participating in interdisciplinary collaboration that is currently absent in existing literature on scientific collaboration. 相似文献