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151.
The use of zero-valent iron for treating wastewaters containing RDX and perchlorate from an army ammunition plant (AAP) in the USA at elevated temperatures and moderately elevated temperature with chemical addition was evaluated through batch and column experiments. RDX in the wastewater was completely removed in an iron column after 6.4 minutes. Increasing the temperature to 75 degrees C decreased the required retention time to 2.1 minutes for complete RDX removal. Perchlorate in the wastewater was completely removed by iron at an elevated temperature of 150 degrees C in batch reactors in 6 hours without pH control. Significant reduction of perchlorate by zero-valent iron was also achieved at a more moderate temperature (75 degrees C) through use of a 0.2 M acetate buffer. Based on the evaluation results, we propose two innovative processes for treating RDX-containing and perchlorate-containing wastewaters: a temperature and pressure-controlled batch iron reactor and subsequent oxidation by existing industrial wastewater treatment plant; and reduction by consecutive iron columns with heating and acid addition capabilities and subsequent oxidation. 相似文献
152.
We present a theory of capital structure based on the power of shareholders, bondholders and managers to control the incentive conflicts in large corporations. The manager–owner conflict produces a trade-off between inefficiency in the low state and rents in the high state, and the shareholder–bondholder conflict produces under-investment as in Myers [Journal of Financial Economics 19 (1997) 147]. Since managers and bondholders both prefer more efficient actions in the low state, the two conflicts are interdependent. With risk-less levels of debt, there are no shareholder–bondholder agency costs, but managerial control over the incentive-setting process produces excessive rents. With risky debt, shareholders focus more on returns in the high state so that shareholder–bondholder agency costs increase but managerial rents decrease. Efficient levels of debt holder protection facilitate a reduction in manager–owner agency costs that outweighs shareholder–bondholder agency costs, and are decreasing in firm performance. The results are consistent with the separate empirical results relating control to both compensation and leverage, and suggest how future studies can be integrated. 相似文献
153.
This paper considers the likely impact of e–commerce and the Internet on the Australian economy. It surveys literature on the extent and development of e–commerce in Australia and its impact on the shape of the Australian economy. Evidence for the 'renewal' of the Australian economy is presented and examined, especially the question of whether Australia has enjoyed increases in productivity as a result of the production and/or use of new information and communications technology. Australia is seen as broadly well placed to benefit from the Internet and e–commerce. Traditionally isolated from the world's main economic centres and reliant on commodities in international trade, the advent of the Internet is ideal for a country in transition to a service–orientated, knowledge–based economy. As the composition of Australia's exports becomes more service–orientated and knowledge–intensive, traditional trading links with Europe and North America may strengthen relative to those with Asia. 相似文献
154.
155.
This research used a weight-of-evidence approach to evaluate sources of contaminants in a drinking water watershed that serves as part of the City of Boston's water supply. The approach incorporated land use analysis using GIS, sanitary surveys, traditional water quality monitoring and microbial source tracking (MST) tools. Case-study tributaries were selected based on elevated faecal coliform counts. Land use analysis and sanitary surveys were used to identify suspected microbial sources, including residential septic systems, agricultural animal operations, commercial/industrial operations and wildlife activity. Sampling sites were selected to hydrologically isolate potential contamination sources. Samples were collected seasonally over 1 year and analysed for traditional and MST parameters. Results demonstrated that both septic systems and a horse stable were contributing microbial loads in the first tributary. In the second tributary, septic systems from the townhouses were contributing microbial loads while a plant nursery was contributing organic matter. This evidence was used to evaluate best management practices to mitigate the contamination. 相似文献
156.
The fate of bromine species from human activity is affected by the bromination reaction in water treatment processes. In this study, kinetic information of the reaction between hypobromous acid (HOBr) and seven different natural organic matters (NOM) was collected by sequential stopped-flow techniques. Multiple reaction phases were found in the reaction between HOBr and NOM. The number of reaction sites for the faster reaction phase ranged from 0.26 to 0.92 micromole (mg DOC)(-1), and was correlated to both SUVA and specific phenolic content at pH 7.0. The apparent second-order rate constants for the faster reaction phase at pH 7.0 ranged from 5.4 x 10(5) to 1.4 x 10(6) M(-1) x s(-1), indicating that vanillin-like structures are involved in this reaction phase. 相似文献
157.
S. J. Ho 《Journal of Economics》2008,93(1):31-58
This paper addresses two very old issues in human society: espionage and double crossing. Our major conclusion points out that there will be a serious over rewarding problem in the direct mechanism due to double
crossing in espionage, and a competitive mechanism with a relative performance regime can possibly mitigate the over rewarding
problem and still extract the information.
相似文献
158.
Antoine Bouët Yvan Decreux Lionel Fontagné Sébastien Jean David Laborde 《Review of International Economics》2008,16(5):850-863
This paper presents MAcMap–HS‐6, a database providing a consistent, ad valorem equivalent measure of tariff duties and tariff rate quotas for 163 countries and 208 partners, at the six‐digit level of the Harmonized System (5111 products), accounting for all preferential agreements. We describe the methodology used to compute and aggregate an ad valorem equivalent of applied protection. Emphasis is placed on minimizing the endogeneity bias in the aggregation procedure, while acknowledging structural differences in export specialization. The resulting quantitative assessment is illustrated by giving an overview of applied protection across the world in 2001, in terms of average as well as distribution. 相似文献
159.
Understanding the Large Negative Impact of Oil Shocks 总被引:1,自引:0,他引:1
This paper offers a plausible explanation for the close link between oil prices and aggregate macroeconomic performance in the 1970s. Although this link has been well documented in the empirical literature, standard economic models are not able to replicate this link when actual oil prices are used to simulate the models. In particular, standard models cannot explain the depth of the recession in 1974–75 and the strong revival in 1976–78 based on the oil price movements in that period. This paper argues that a missing multiplier-accelerator mechanism from standard models may hold the key. 相似文献
160.