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121.
This paper is a review of research in Chicago that linked analyses of vegetation structure with forest functions and values. During 1991, the regions trees removed an estimated 5575 metric tons of air pollutants, providing air cleansing worth 9.2 million. Each year they sequester an estimated 315 800 metric tons of carbon. Increasing tree cover 10% or planting about three trees per building lot saves annual heating and cooling costs by an estimated 50 to 90 per dwelling unit because of increased shade, lower summertime air temperatures, and reduced neighborhood wind speeds once the trees mature. The net present value of the services trees provide is estimated as 402 per planted tree. The present value of long-term benefits is more than twice the present value of costs.  相似文献   
122.
The underlying assumptions of the Rai and Van Ryzin dose-response model for reproductive toxicological data are evaluated on the basis of existing experimental data. The model under consideration is unusual in its use of litter size to completely account for extra-binomial variation in the data by associating litter size with reproductive outcome. The experimental data show that controlling litter size is not sufficient to account for the litter-to-litter variability in responses. It is also shown that the two linear components of the Rai and Van Ryzin model are inappropriate. For the component which applies to the dam, the data suggest a strong nonlinearity, supported by rejection of the linear model via statistical hypothesis tests. In the component involving litter size, a relationship with dose is not apparent. The litter size parameters offer considerable potential for bias in estimation; bias which is at least partly masked by the model having good prediction characteristics due to the increased number of parameters. A simulation study is presented to illustrate how the Rai and Van Ryzin model can exaggerate litter size effects on the probability of response when the simulated data arise from a model involving a nonlinear dam component, common to this type of data, and no effect of litter size.  相似文献   
123.
The lack of comparison groups is a common problem for researchers conducting evaluations of small, specialized programs. When conventional comparison groups are not available, the authors suggest a possible alternative approach which involves: (a) locating a sub-group in a national study for whom relevant variables have been measured; (b) generating a statistical model which predicts the outcome of interest in the national data; and (c) applying the predictive model to program data, in order to estimate outcomes in the absence of progam intervention. The authors illustrate this new application by presenting the results of an analysis of data from Project Talent, a national manpower study, and discuss its application to the evaluation of a medical training program in New York City.  相似文献   
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We propose a novel literature review method in order to systematically trace and reveal the dominant narratives of a body of literature: the model‐narrative review method. We apply this method to an ever‐growing literature on ecosystems in business studies, as it resembles a rich knowledge base with somewhat competing, overarching stories, replete with emplotted characters, systematic puzzles and embellished scientific drama. To interpret these unfolding storylines, we both separately engage with and connect seminal work on business, entrepreneurial and innovation ecosystems. Through thematic reading we map the key themes and scientific puzzles in each ecosystem type. Through enstoried reading we identify how authors construct the plot, narrative setting, emplotted characters, narrative voices and moral lessons around ecosystems. Through rhetorical reading we explicate the rhetorical devices and strategies that claim the relevance of their work. Our findings expose a number of hidden meanings and underlying assumptions, adding transparency to ecosystem rhetorics and enhancing conceptual clarity. Altogether, this method offers a systematic construction of model‐narratives to synthesize and critically reflect upon similarities and differences between related concepts and opens up space for alternative research questions.  相似文献   
127.
Increasing residential insulation can decrease energy consumption and provide public health benefits, given changes in emissions from fuel combustion, but also has cost implications and ancillary risks and benefits. Risk assessment or life cycle assessment can be used to calculate the net impacts and determine whether more stringent energy codes or other conservation policies would be warranted, but few analyses have combined the critical elements of both methodologies In this article, we present the first portion of a combined analysis, with the goal of estimating the net public health impacts of increasing residential insulation for new housing from current practice to the latest International Energy Conservation Code (IECC 2000). We model state-by-state residential energy savings and evaluate particulate matter less than 2.5 microm in diameter (PM2.5), NOx, and SO2 emission reductions. We use past dispersion modeling results to estimate reductions in exposure, and we apply concentration-response functions for premature mortality and selected morbidity outcomes using current epidemiological knowledge of effects of PM2.5 (primary and secondary). We find that an insulation policy shift would save 3 x 10(14) British thermal units or BTU (3 x 10(17) J) over a 10-year period, resulting in reduced emissions of 1,000 tons of PM2.5, 30,000 tons of NOx, and 40,000 tons of SO2. These emission reductions yield an estimated 60 fewer fatalities during this period, with the geographic distribution of health benefits differing from the distribution of energy savings because of differences in energy sources, population patterns, and meteorology. We discuss the methodology to be used to integrate life cycle calculations, which can ultimately yield estimates that can be compared with costs to determine the influence of external costs on benefit-cost calculations.  相似文献   
128.
Feeling at Risk Matters: Water Managers and the Decision to Use Forecasts   总被引:1,自引:0,他引:1  
Experts contend that weather and climate forecasts could have an important role in risk management strategies for community water systems. Yet, most water managers make minimal use of these forecasts. This research explores the determinants of the use of weather and climate forecasts by surveying managers of community water systems in two eastern American states (South Carolina and the Susquehanna River Basin of Pennsylvania). Assessments of the reliability of weather and climate forecasts are not driving their use as water managers who find forecasts reliable are no more likely to use them than are managers who find them unreliable. Although larger systems and those depending on surface water are more likely to use forecasts for some (but not all) purposes, the strongest determinant of forecast use is risk perceptions. Water managers who expect to face problems from weather events in the next decade are much more likely to use forecasts than are water managers who expect few problems. Their expectations of future problems are closely linked with past experience: water managers who have had problems with specific types of weather events (e.g., flood emergencies) in the last 5 years are likely to expect to experience problems in the next decade. Feeling at risk, regardless of the specific source of that weather-related risk, stimulates a decision to use weather and climate forecasts.  相似文献   
129.
The actions of organizational leaders are important determinants of the emergence, management, and consequences of employee emotional experience. However, the nature and dimensionality of leader emotion management and the behaviors that constitute such management are largely unknown. The authors present a comprehensive, theoretically-derived model of leader emotion management which clarifies the nature of emotion management and its role in leadership. This model also delineates the knowledge and skill-based antecedents of emotion management and the consequences of such management. Specifically, we propose linkages between particular KSAOs and specific emotion management dimensions and between those dimensions and particular individual and organizational outcomes. The model is meant to serve as a framework to guide empirical efforts in investigating the nature and correlates of leader emotion management.  相似文献   
130.
Safety Risk Analysis of an Innovative Environmental Technology   总被引:1,自引:0,他引:1  
The authors describe a decision and risk analysis performed for the cleanup of a large Department of Energy mixed-waste subsurface disposal area governed by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). In a previous study, the authors worked with the site decision makers, state regulators, and U.S. Environmental Protection Agency regional regulators to develop a CERCLA-based multiobjective decision analysis value model and used the model to perform a screening analysis of 28 remedial alternatives. The analysis results identified an innovative technology, in situ vitrification, with high effectiveness versus cost. Since this technology had not been used on this scale before, the major uncertainties were contaminant migration and pressure buildup. Pressure buildup was a safety concern due to the potential risks to worker safety. With the help of environmental technology experts remedial alternative changes were identified to mitigate the concerns about contaminant migration and pressure buildup. The analysis results showed that the probability of an event with a risk to worker safety had been significantly reduced. Based on these results, site decision makers have refocused their test program to examine in situ vitrification and have continued the use of the CERCLA-based decision analysis methodology to analyze remedial alternatives.  相似文献   
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