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51.
Water fluoridation is a controversial issue in public health. Despite the uncertainty regarding its efficacy and safety, health officials continue to communicate it as ‘unequivocally’ safe and effective. Our focus is on how health officials and policy-makers in Israel frame the issue of water fluoridation in terms of certainty while promoting a mandatory fluoridation policy. According to van Asselt and Vos, the uncertainty paradox describes situations in which uncertainty is acknowledged, but the role of science is framed as providing certainty. Our study is an analysis of documents and media articles emphasizing the paradoxical language used by official representatives on the controversial topic of fluoridation. A central contribution of this study is that we coin the term ‘uncertainty bias,’ in which policy-makers do exactly what they accuse laypeople of doing, framing uncertainty in biased terms. We found that in order to establish mandatory regulation, health ministry officials expressed information in an unbalanced format, promoting the topic of fluoridation by framing it in exclusively positive terms. This study does not focus on the practice of water fluoridation per se, and is not intended to decide for or against it, but rather, to explore how the debate regarding it is communicated. Understanding this particular case can shed light on how other controversial topics are transformed into health policy that is characterized in equivocal terms.  相似文献   
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离子色谱是高效液相色谱法当中的一类,又被称之为现代离子色谱。作为一种高效科学的检测方法,离子色谱发展迅速,被广泛用于大气、土壤和水质检测中。本文主要综述了离子色谱法应用于生活饮用水检测的研究进展。  相似文献   
54.
At the beginning of the 21st century, the Netherlands and Flanders introduced a risk-based approach to flood risk management (FRM), labelled as multi-layer (water) safety. In contrast to a flood defence approach, risk-based management stresses the need to manage both the consequences and probability of a flood. The concept has developed differently in the two countries, as we conclude from a discursive-institutionalist research perspective. The Netherlands is characterised by a high institutionalization of the traditional flood defence discourse and a more closed policy arrangement, whereas in Flanders, the flood defence discourse is less institutionalized and the arrangement is more open. In both countries we see an opening of the arrangement preceding the establishment of multi-layer (water) safety, but at the same time, actors stress different aspects of the concept in order to increase its compatibility with the existing policy arrangement. In the Netherlands, the focus is on probability management, in Flanders on consequence management. In the Netherlands, multi-layer (water) safety as a concept could be established because it stabilises the system in the short-term by reinforcing the importance of flood defence, whereas in Flanders, policymakers were receptive to the concept because it supports a shift of responsibility towards actors outside traditional water management.  相似文献   
55.
Air and groundwater temperatures were measured in a rimstone pool in Postojna Cave, to advise evaluation of the impact of natural and anthropogenic influences related to heat being initially transmitted into cave air by visitors. Such heat can accumulate both in the rock mass and in water. Results show that attention must be paid to temperature changes of rimstone pool water rather than those of cave air, especially during the winter. Thanks to good ventilation deep inside the cave, short-term air temperature increases related to higher visitor numbers have not influenced flowstone precipitation or the cave fauna. However, this situation might change if winter visitor numbers increased greatly. This study does not support a suggested increase in winter visits (currently the tourism low-season) and reduction of summer visits (currently the tourism high-season).  相似文献   
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巷道快速掘进技术是一项系统工程。为了实现矿井高产高效,必须以巷道快速掘进技术为前提和保障。本文以贵州省为例,探讨了巷道快速掘进技术的研究现状及影响因素。针对贵州某矿突出综合检测指标经常超限、掘进速度慢等问题,采用了高压水射流割缝与瓦斯抽放边抽边掘相结合技术。研究表明:该项技术能有效削弱煤层突出危险性,大幅度提高瓦斯抽放量且巷道掘进速度提高了2~3倍。同时根据贵州省的本土情况,提出了针对性地建议和措施,能为巷道快速掘进技术的推广与应用提供一定的指导。  相似文献   
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矿井工作面瓦斯超限严重影响着矿井安全生产和生产效率,现用解决该问题的方法存在局限性,不能广泛适用于所有矿井。针对该问题,采用水及含添加剂水阻碍和延缓煤体内瓦斯解吸速度,以达到降低工作面瓦斯涌出量的目的。本文通过对其抑制原理相关研究的介绍,为同类工作面瓦斯超限治理提供基础理论依据。  相似文献   
58.
王平  王肖霞 《价值工程》2014,(29):70-71
文章分析了锅炉水位控制系统的基本原理及结构,针对传统PID控制器的不足之处设计了基于遗传算法的新型锅炉水位控制器,在此基础上搭建了锅炉水位控制系统。最后,通过仿真验证了该水位控制器在改善水位系统稳态误差及动态超调方面均具有较好的作用。  相似文献   
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矿井涌水量计算是矿床水文地质勘查中一项重要而复杂的工作,也是矿床水文地质勘查中的根本任务之一。运用大井法和廊道法对首采区、首采工作面和开切眼涌水量进行了预计,认为大井法计算的涌水量成果较为可靠,矿井最大涌水量为296.80m3/h,为今后的矿井安全生产提供了理论依据。  相似文献   
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