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901.
Vitamin D is vital in all vertebrates because it allows them to absorb more calcium from their diets, contributing to stronger skeletal systems, and taller statures. Using a source of 19th century US state prison records, this study contrasts the statures of comparable African-Americans and whites by the primary sources of vitamin D production: time exposed to solar radiation, skin pigmentation, and nativity. Greater insolation (sunlight) is documented here to be associated with taller black and white statures, and a considerable share of the stature differential by socioeconomic status was related to insolation.  相似文献   
902.
This study uses 59 biographical variables to create a “bio-index” for forecasting U.S. presidential elections. The bio-index method counts the number of variables for which each candidate rates favorably, and the forecast is that the candidate with the highest score would win the popular vote. The bio-index relies on different information and includes more variables than traditional econometric election forecasting models. The method is useful in combination with simple linear regression to estimate a relationship between the index score of the candidate of the incumbent party and his share of the popular vote. The study tests the model for the 29 U.S. presidential elections from 1896 to 2008. The model's forecasts, calculated by cross-validation, correctly predicted the popular vote winner for 27 of the 29 elections; this performance compares favorably to forecasts from polls (15 out of 19), prediction markets (22 out of 26), and three econometric models (12 to 13 out of 15 to 16). Out-of-sample forecasts of the two-party popular vote for the four elections from 1996 to 2008 yielded a forecast error almost as low as the best of seven econometric models. The model can help parties to select the candidates running for office, and help to improve on the accuracy of election forecasting, especially for longer-term forecasts.  相似文献   
903.
Customer Response to Carbon Labelling of Groceries   总被引:3,自引:0,他引:3  
Thirty-seven products were labelled to indicate embodied carbon emissions, and sales were recorded over a 3-month period. Green (below average), yellow (near average), and black (above average) footprints indicated carbon emissions embodied in groceries. The overall change in purchasing pattern was small, with black-labelled sales decreasing 6% and green-labelled sales increasing 4% after labelling. However, when green-labelled products were also the cheapest, the shift was more substantial, with a 20% switch from black- to green-label sales. These findings illustrate the potential for labelling to stimulate reductions in carbon emissions.  相似文献   
904.
Prior research shows that firms benefit from the social capital of their boards of directors but has not explored the antecedents of new director social capital. We argue that firms can attract directors with social capital by offering more compensation. We also argue that more complex firms (firms with a greater scale and scope of operations) are more attractive to such directors because of the greater experience and exposure that such directorships provide. Similarly, we argue that firms with high‐status directors on their current boards will be more attractive to directors with social capital. We analyse the social capital of new outside directors added to boards of semiconductor firms between 1993 and 2007. Surprisingly, we find no support for the hypothesis that higher compensation is associated with adding directors with high status or board ties. However, firm complexity is associated with the ability to add new directors who have social capital, and the status of current board members is associated with the ability to add new directors who also have high status.  相似文献   
905.
The potential of group (vs. individual) forecasting is analyzed from the perspective of the social psychology of groups. The social decision scheme theory (SDST) is summarized, and several simulations are presented to demonstrate the dependence of group aggregation accuracy upon factors such as group size, the accuracy and distribution of individual forecasts, and shared representations of the forecasting problem. Many advantages and disadvantages of group aggregation are identified and related to four generic methods of group aggregation (statistical aggregation, prediction markets, the Delphi method, and face-to-face discussion). A number of aspects of forecasting problems are identified which should govern whether or not group forecasting can be relied upon, and if so, what aggregation method should be used.  相似文献   
906.
The current statutory and regulatory guidance for recovery audit contractor (RAC) extrapolation leaves providers with minimal protection against the process and a limited ability to challenge overpayment demands. Providers not only should understand the statutory and regulatory basis for extrapolation forecast, but also should be able to assess their extrapolation risk and their recourse through regulatory safeguards against contractor error. Providers also should aggressively appeal all incorrect RAC denials to minimize the potential impact of extrapolation.  相似文献   
907.
This paper assesses the efficacy and relevance of focus groups as participative tools for land use policy and planning. The use of focus groups has mushroomed in land use research and policy in response to new governance and empowerment agendas with their emphasis on using more deliberative and participative approaches. However, their use within social science research has been controversial given perceived methodological limitations of rigour and bias. A detailed critique of three recent research projects has been undertaken to assess focus group in theory and practice; rural diversification, public perception of landscape and visitor payback. The assessment considers key questions relating to inclusion, participation, empowerment, policy impact and understanding of complex policy issues. The results show that focus groups can perform multiple roles as exploratory, explanatory, participative and deliberative tools. Nevertheless, focus groups have important limitations and methodological protocols which demand more care and attention. Crucially, they should not be used in isolation to influence policy decisions; end user pressure for quick fixes, group dynamics, issues of representativeness, together with the biases of a facilitator, can easily mask, distort or misrepresent results. It is concluded that focus groups have significant potential as qualitative tools in landscape research but that they must be used carefully and in tandem with other techniques if their true potential is to be realised.  相似文献   
908.
The 1930s witnessed an intense struggle between gas and electricity suppliers for the working class market, where the incumbent utility—gas—was also a reasonably efficient (and cheaper) General Purpose Technology for most domestic uses. Local monopolies for each supplier boosted substitution effects between fuel types—as alternative fuels constituted the only local competition. Using newly-rediscovered returns from a major national household expenditure survey, we employ geographically-determined instrumental variables, more commonly used in the industrial organization literature, to show that gas provided a significant competitor, tempering electricity prices, while electricity demand was also responsive to marketing initiatives.  相似文献   
909.
In recent years, the public has become increasingly concerned about the safety of the food they eat. Anxieties are augmented each time there is a food crisis, with each new disease and resultant food safety concern adding to the perception that our food is no longer safe. Bridging the gap between the scientist/veterinarian, economist, farmer and consumer requires effective communication strategies. This article uses the example of paratuberculosis (Johne's disease) in cattle to illustrate the difficulties of communicating food-safety risks when considerable uncertainty exists. Scientific data linking this disease to Crohn's disease in humans is contradictory and far from conclusive. We show how the Codex Alimentarius system can be used as a template for communicating risk in such situations. This is a four-stage process that addresses public perceptions of the risk and the public's related information requirements. One aim is to give peoples' concerns as much emphasis as the risk statistics in an open and honest debate. The example highlights the difficulty of deciding when and how best to instigate the process. However, positive collaboration between epidemiologists, public health specialists, economists, food marketers and policy-makers to work in conjunction with consumers of both food and animal health products and services is essential for a satisfactory outcome.  相似文献   
910.
Multichannel customer management is “the design, deployment, and evaluation of channels to enhance customer value through effective customer acquisition, retention, and development” (Neslin, Scott A., D. Grewal, R. Leghorn, V. Shankar, M. L. Teerling, J. S. Thomas, P. C. Verhoef (2006), Challenges and Opportunities in Multichannel Management. Journal of Service Research 9(2) 95–113). Channels typically include the store, the Web, catalog, sales force, third party agency, call center and the like. In recent years, multichannel marketing has grown tremendously and is anticipated to grow even further. While we have developed a good understanding of certain issues such as the relative value of a multichannel customer over a single channel customer, several research and managerial questions still remain. We offer an overview of these emerging issues, present our future outlook, and suggest important avenues for future research.  相似文献   
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