首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   915篇
  免费   60篇
  国内免费   6篇
财政金融   32篇
工业经济   48篇
计划管理   405篇
经济学   99篇
综合类   106篇
运输经济   16篇
旅游经济   9篇
贸易经济   129篇
农业经济   32篇
经济概况   105篇
  2024年   7篇
  2023年   12篇
  2022年   22篇
  2021年   20篇
  2020年   30篇
  2019年   8篇
  2018年   11篇
  2017年   8篇
  2016年   16篇
  2015年   48篇
  2014年   74篇
  2013年   90篇
  2012年   99篇
  2011年   137篇
  2010年   106篇
  2009年   58篇
  2008年   57篇
  2007年   43篇
  2006年   41篇
  2005年   20篇
  2004年   19篇
  2003年   16篇
  2002年   13篇
  2001年   6篇
  2000年   7篇
  1999年   3篇
  1998年   1篇
  1997年   3篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1990年   1篇
  1985年   1篇
排序方式: 共有981条查询结果,搜索用时 15 毫秒
11.
李军 《科技和产业》2021,21(8):295-300
公路改扩建工程在广东省正处于快速发展时期,如何准确得到路面病害情况,是旧路处治方案制定面临的主要问题.依托开阳高速改扩建工程,采用三维探地雷达对旧路进行病害检测,得到道路表面及内部的病害分布情况,并分别与人工徒步调查路况及开挖后内部实际情况进行比对.结果表明:当三维探地雷达检测采样间距设置为2.0 cm、驻波时间设置为0.6 ms、时窗设置为85 ns时,可达到较好的检测精准度;三维探地雷达可实现对路面结构内部不同深度位置的裂缝病害进行探测,精确识别3 mm宽裂缝,并了解裂缝的发展方向及性质.  相似文献   
12.
The knowledge of a product's life cycle is the first step on the search of sustainable development. The life cycle assessment (LCA) is an important method because it allows an environment accounting, where the extraction of natural resources and energy of the nature are considered and the "returns" to the same one and allows in evaluating relative potential the environment impacts generated. The present work had as objective to make an analysis of material and energy flows of the life cycle of three types of packaging for soft drinks: glass bottles of 390 mL, aluminum cans of 350 mL, and bottles of PET of 2,000 mL. The study considered processes since the extraction of raw materials for production of the packaging until the stages of recycling, after the consumption of the soft drink. For the research, an inventory analysis followed the LCA methodology. The main critical points of generation of negative environmental impact during the life cycle of each packaging had been the identified and quantified data in this study. The consumption of natural resources like water and other raw materials and energy, the generation of atmospheric emissions, solid wastes and wastewaters had been the analyzed categories. The results showed that, in accordance with the scenes and defined variables, the most important conclusion was that the bottle of glass presented a less favorable scene to the environment in comparison with other packaging.  相似文献   
13.
Regional banks have a competitive advantage in that short distances to clients enable the use of soft information for superior lending decisions. If the ambition of FinTech start-ups to create superior screening and monitoring technologies materialises, this advantage would be diminished and regional banks would become superfluous for small firm finance. To explore this claim, the paper in hand analyses qualitative empirical data about the lending processes and rating system use of regional German savings banks. In essence, the results from participant observation and interviews clarify the importance of “real” soft information for critical lending decisions. The context specificity and limited verifiability of “real” soft information hamper it from being hardened through the use of rating systems and other bank-ICT. Though FinTech's scoring technologies may overcome the first limitation, it appears likely that in the course of scoring development “real” soft information will be systematically crowded out due to the manipulation problem. The paper expects improved access to finance for SMEs if FinTech solutions overcome both limitations of “real” soft information use, or if peer-to-peer lending and regional banks coexist. Deteriorated access to finance is expected if FinTech companies displace the relationship banking of regional banks due to enhanced competition, without preserving the advantages of “real” soft information with superior screening and monitoring technologies. The paper concludes with recommendations on how to prevent deteriorated access to finance for small firms by promoting fair competition and FinTech innovations.  相似文献   
14.
Many planning authorities and airports study measures to increase public transport use for airport ground access and egress. At the same time, an increase in real estate development at and around airports is occurring, both due to airports seeking new revenue possibilities and other developers attempting to profit from high value locations. This paper considers non-aeronautical activities at large airports, largely commercial centres and transit hubs, as land uses that have the potential to improve the situation for operating public transport services. In order to assess potential benefits and disadvantages, four research questions are considered: (1) Can the additional travel volume reach levels at which it has a significant impact? (2) To what extent do non-aeronautical activities influence the public transport access system? (3) Is the resulting demand distribution better or worse regarding peaking behaviour? (4) Is there a potential for the resulting overall demand to bring about capacity shortages?A case study is conducted at the airport of Zurich, Switzerland, which finds that non-aeronautical activities in the direct airport vicinity have led to a situation where the operation of public transport services is much more viable due to overall higher passenger numbers and a more even distribution throughout the day. It is concluded that locating non-aeronautical activities at airports can, in addition to providing commercial benefits to developers, lead to a situation where improved public transport services become feasible.  相似文献   
15.
翟中超 《价值工程》2015,(19):139-141
目前正处于煤炭行业的寒潮时期,各地煤炭企业亏损严重。为了响应国家的安全生产方针,煤炭企业在该时期生产过程中安全方面更不敢出一丝的问题。由于综采工艺相比其他采煤工艺而言大大提高了施工人员的安全系数。所以,综采工艺往往是工作面回采的首选。河南能源化工集团焦煤公司中马村矿同样采用了综采工艺对211021工作面进行回采。211021综采工作面为顶层工作面,并且所采煤层煤质较软,初采初放期间遇到了三条断层。下面就211021综采工作面回采初期的技术管理进行简要的分析总结。  相似文献   
16.
We analyse the impact of ownership and corporate control on firms’ investment using the 2001 survey of Yacoub et al. on Ukrainian firms. The model explains investment by output, financial and soft budget constraints, and corporate control (and ownership) categories potentially enjoying private benefits of control. We find that the corporate control model fits better than the ownership model, a negative relationship between state and employee control and firms’ investment, and evidence for the presence of soft budget constraints. A negative relationship between firms’ investment and the relative size of non‐monetary transactions strengthens the conclusion of private benefits of control impacting investment.  相似文献   
17.
黄遵响 《价值工程》2015,(12):136-139
本文以电网运行中常见的一起10k V系统接地故障查找方法为例,通过分析得出了10k V金属性接地故障的原因,大致可分为以下三类:110k V单一线路接地故障;2两条及以上线路同名相接地;310k V母线设备故障。在此基础上,作者以自己亲身工作经历,讲述了快速排查接地方法、步骤。并提出了相关的改进建议和措施,以确保故障处理快速、正确。  相似文献   
18.
针对鹤煤九矿井下硐室出现浆皮开裂、底臌等类似现象,采用相似模拟的方法,以鹤煤九矿31采区避难硐室临近硐室群实际地质资料为基础,研究分析了给定应力环境下不同支护方式时硐室围岩的变形破坏情况、失稳过程。作者认为,随着顶部压力的逐渐改变,顶板裂隙逐渐增加,裂隙深度和宽度逐步增加,巷道出现离层、底鼓,进而呈现大面积破坏。该结果对区段巷道布置与加固方案优化有一定的参考价值。  相似文献   
19.
Soft skills are typically referred to as the attributes exhibited or contained by an individual that display his/her ability to interact with others. Two types of soft skills that are often discussed within the hospitality industry are diversity awareness and emotional intelligence. Diversity may be explained or defined as a state of unlikeness, the conditions of being different, and all things that make us different. Areas where differences may exist include race, ethnicity, gender, sexual orientation, socio-economic status, age, physical abilities, religious beliefs, political affiliation and emotional reaction. Emotional intelligence (EI) has been defined as the ability to perceive, understand, regulate, and harness emotions in the self and others. How one deals with emotion is one characteristic that varies from culture to culture. Research has shown that EI may be a contributing factor in a moment of truth being considered a failure or success. The purpose of this study was to examine if undergraduate student EI scores change after completing a diversity issues course. Students completed the Assessing Emotions Scale on the first class day. At the conclusion of the 15-week course covering approximately 20 diversity issues concepts students completed the same EI assessment. Paired sampled t-testing was conducted to determine whether mean differences existed when comparing post and pre-course scores. Results of this study suggest that certain components of EI are significantly changed after taking the diversity issues course.  相似文献   
20.
徐国领 《价值工程》2013,(30):97-98
通过对回风斜井的围岩性质及巷道破坏原因分析,结合数值模拟,提出了U型钢支架与短锚杆全长锚固巷道底角加锚索并喷射混凝土封闭围岩支护治理方案。经实验表明,上述方案的实施取得了良好的支护效果。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号