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Gergely Simon Caroline Busch Marco A. B. Andrade Julien Reboud Jonathan M. Cooper Marc P. Y. Desmulliez Mathis O. Riehle Anne L. Bernassau 《Biomicrofluidics》2021,15(1)
Separation and sorting of biological entities (viruses, bacteria, and cells) is a critical step in any microfluidic lab-on-a-chip device. Acoustofluidics platforms have demonstrated their ability to use physical characteristics of cells to perform label-free separation. Bandpass-type sorting methods of medium-sized entities from a mixture have been presented using acoustic techniques; however, they require multiple transducers, lack support for various target populations, can be sensitive to flow variations, or have not been verified for continuous flow sorting of biological cells. To our knowledge, this paper presents the first acoustic bandpass method that overcomes all these limitations and presents an inherently reconfigurable technique with a single transducer pair for stable continuous flow sorting of blood cells. The sorting method is first demonstrated for polystyrene particles of sizes 6, 10, and 14.5 μm in diameter with measured purity and efficiency coefficients above 75 ± 6% and 85 ± 9%, respectively. The sorting strategy was further validated in the separation of red blood cells from white blood cells and 1 μm polystyrene particles with 78 ± 8% efficiency and 74 ± 6% purity, respectively, at a flow rate of at least 1 μl/min, enabling to process finger prick blood samples within minutes. 相似文献
73.
The retention and resilience of teachers are subject to many influences. Children’s behaviour is often cited as a major source of stress for teachers and a challenge to their resilience. We suggest that an understanding of teachers’ attributions and efficacy beliefs may provide the foundations for work to support teachers. We outline findings from research that has examined teachers’ attributions for the causes of children’s misbehaviour, teachers’ beliefs in their efficacy as classroom managers of children’s behaviour as well as how, in principle, such beliefs may be supported and enhanced. We also relate these findings to those associated with educational and developmental outcomes for children. We conclude with some illustrative evidence of ways (involving consultation and other interventions) that applied psychologists have contributed to the professional well-being and resilience of teachers. 相似文献
74.
Decision-making is a complex process that is largely studied from an experimental perspective or in specific organizational contexts. As such, no generalizable framework exists with which to study decision-making from an individual differences perspective for predictive/selection purposes. By generalising a context-specific decision model proposed by Koriat and Goldsmith (1996), the focus of this research was to therefore test a novel framework for studying individual differences in decision-making tendencies. Utilising this framework within a fictitious Medical Decision-Making Test (MDMT) yielded five novel variables that provided unique insight into individuals’ decision tendencies: Optimal, Realistic, Incompetent, Hesitant and Congruent. Metacognitive confidence and its calibration (bias and CAQ) were used as predictor variables to validate this framework. One hundred ninety-three undergraduate students completed the MDMT and three cognitive ability tests with confidence ratings, a personality questionnaire, and the Need for Closure questionnaire. All decision tendency variables demonstrated excellent internal consistency and were predicted by the metacognitive variables incrementally to the remaining variables as hypothesized. Additionally, the metacognitive indices were found to generalize across the decision-making and cognitive tests. The results imply that this novel framework and MDMT reliably capture individuals’ decision behaviour that shares a meaningful relationship with their general confidence and calibration. 相似文献
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This study examined the utility of motivation as advanced by self-determination theory (Deci & Ryan, 2000) in predicting objectively assessed bouts of moderate intensity exercise behavior. Participants provided data pertaining to their exercise motivation. One week later, participants wore a combined accelerometer and heart rate monitor (Actiheart; Cambridge Neurotechnology Ltd) and 24-hr energy expenditure was estimated for 7 days. After controlling for gender and a combined marker of BMI and waist circumference, results showed autonomous motivation to positively predict moderate-intensity exercise bouts of >or=10 min, or=20 min, and an accumulation needed to meet public health recommendations for moderate intensity activity (i.e., ACSM/AHA guidelines). The present findings add bouts of objectively assessed exercise behavior to the growing body of literature that documents the adaptive consequences of engaging in exercise for autonomous reasons. Implications for practice and future work are discussed. 相似文献
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Stefanie Demming Gena Peterat Andreu Llobera Hannah Schmolke Alexander Bruns Michael Kohlstedt Ala‘aldeen Al-Halhouli Claus-Peter Klages Rainer Krull Stephanus Büttgenbach 《Biomicrofluidics》2012,6(3)
This paper presents a vertically positioned microfluidic system made of poly(dimethylsiloxane) (PDMS) and glass, which can be applied as a microbubble column (μBC) for biotechnological screening in suspension. In this μBC, microbubbles are produced in a cultivation chamber through an integrated nozzle structure. Thus, homogeneous suspension of biomass is achieved in the cultivation chamber without requiring additional mixing elements. Moreover, blockage due to produced carbon dioxide by the microorganisms—a problem predominant in common, horizontally positioned microbioreactors (MBRs)—is avoided, as the gas bubbles are released by buoyancy at the upper part of the microsystem. The patterned PDMS layer is based on an optimized two-lithographic process. Since the naturally hydrophobic PDMS causes problems for the sufficient production of microbubbles, a method based on polyelectrolyte multilayers is applied in order to allow continuous hydrophilization of the already bonded PDMS-glass-system. The μBC comprises various microelements, including stabilization of temperature, control of continuous bubble formation, and two optical configurations for measurement of optical density with two different sensitivities. In addition, the simple and robust application and handling of the μBC is achieved via a custom-made modular plug-in adapter. To validate the scalability from laboratory scale to microscale, and thus to demonstrate the successful application of the μBC as a screening instrument, a batch cultivation of Saccharomyces cerevisiae is performed in the μBC and compared to shake flask cultivation. Monitoring of the biomass growth in the μBC with the integrated online analytics resulted in a specific growth rate of 0.32 h−1, which is almost identical to the one achieved in the shake flask cultivation (0.31 h−1). Therefore, the validity of the μBC as an alternative screening tool compared to other conventional laboratory scale systems in bioprocess development is proven. In addition, vertically positioned microbioreactors show high potential in comparison to conventional screening tools, since they allow for high density of integrated online analytics and therefore minimize time and cost for screening and guarantee improved control and analysis of cultivation parameters. 相似文献
80.
This paper examines how innovation-related capabilities for production, design and marketing develop at the subsidiary level within multinational enterprises (MNEs). We focus on how subsidiary autonomy and changing opportunities to access external (host country) sources of capability contribute to the accumulation of specialist capabilities in five Taiwan-based MNE subsidiaries in the semiconductor industry. Longitudinal analysis shows how the accumulation process is subject to discontinuities, as functional divisions are (re)opened and closed during the lifetime of the subsidiary. A composite set of innovation output measures also shows significant variations in within-function levels of capability across our sample. We conclude that subsidiary specialisation and unique subsidiary-specific advantages have evolved in a way that is strongly influenced by the above factors. 相似文献