全文获取类型
收费全文 | 6615篇 |
免费 | 416篇 |
国内免费 | 149篇 |
专业分类
财政金融 | 47篇 |
工业经济 | 137篇 |
计划管理 | 464篇 |
经济学 | 574篇 |
综合类 | 186篇 |
运输经济 | 15篇 |
旅游经济 | 36篇 |
贸易经济 | 155篇 |
农业经济 | 751篇 |
经济概况 | 289篇 |
水利工程 | 4526篇 |
出版年
2024年 | 19篇 |
2023年 | 75篇 |
2022年 | 163篇 |
2021年 | 139篇 |
2020年 | 136篇 |
2019年 | 155篇 |
2018年 | 182篇 |
2017年 | 203篇 |
2016年 | 225篇 |
2015年 | 258篇 |
2014年 | 349篇 |
2013年 | 483篇 |
2012年 | 407篇 |
2011年 | 511篇 |
2010年 | 348篇 |
2009年 | 446篇 |
2008年 | 435篇 |
2007年 | 527篇 |
2006年 | 378篇 |
2005年 | 380篇 |
2004年 | 250篇 |
2003年 | 229篇 |
2002年 | 182篇 |
2001年 | 165篇 |
2000年 | 134篇 |
1999年 | 100篇 |
1998年 | 69篇 |
1997年 | 28篇 |
1996年 | 40篇 |
1995年 | 46篇 |
1994年 | 29篇 |
1993年 | 23篇 |
1992年 | 23篇 |
1991年 | 8篇 |
1990年 | 5篇 |
1989年 | 14篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有7180条查询结果,搜索用时 349 毫秒
1.
2.
This study investigates the importance of mindfulness‐based organization systems and policies on the organization's continuous efforts to become a greener company. The study is devised as a pooled cross‐sectional time series analysis of productivity in energy consumption, water utilization, and waste generation and recycling of U.S. companies. The data set taken from U.S. Newsweek 500 recorded 600 companies dispersed into 63 industries during the period of 2012–2014 and provided 1,498 company–industry–year observations. The study found that systems and policies (e.g., deployment of third‐party auditors for its environmental metrics report; linkage of the remuneration of company's senior executive team with the achievement of environmental performance targets; and establishment of a committee at the Board of Directors' level whose mandate includes sustainability of the company in environment‐ and resource‐related matters) connect the company's mindfulness to its effort in improving the environmental quality through the company's productivity in energy consumption, water utilization, and waste generation and recycling. The relationships are positive and significant. Also, systems and policies serve as a motivator for the firm to continue to improve upon the current achievements. The study emphasizes the importance of translating organizational and individual mindfulness into organization policies and systems in order to motivate the organization to continuously improve its productivity in energy consumption, water utilization, and waste generation and recycling leading to improvements in environmental quality. 相似文献
3.
In the retail industry, backroom inventories are typically associated with higher labor costs and greater operational complexity. Thus, retailers look for ways to eliminate backroom inventories. A heuristic used for this purpose is the pack‐and‐a‐half rule which suggests that the shelf space allocated for a product should be at least 50% larger than the case pack quantity in which the product is delivered. Despite its popularity among retailers, the pack‐and‐a‐half rule has been ignored in the academic literature. We introduce the pack‐and‐a‐half rule, assess its impact on a retailer's profits, identify cost, demand, and product characteristics driving this impact, and propose a modification. Based on an analysis of data obtained from a retailer on 1,986 SKUs in 20 categories, we find that the pack‐and‐a‐half rule decreases a retailer's profits, on average, by 10% when applied uniformly across all SKUs. Further, this decrease is significantly affected by product depth, product width, demand elasticity, case pack quantity, and inventory carrying cost. Finally, we develop a set of modifications based on these variables where the pack‐and‐a‐half rule is applied selectively and in a stepwise fashion. These modifications limit the decrease in a retailer's profits to a range between 6% and 7%. 相似文献
4.
Gerardo Angeles-Castro Laura Josselin Arriola-Barcenas Carlos Bonifacio Baeza-Almaraz 《Applied economics letters》2018,25(21):1531-1534
By using panel data analysis across 368 water utilities in Mexico over the period 2010–2014, we find that small firms are more efficient than medium and large providers and that increasing production is associated with less efficiency. Billing, income collection and profitability are relevant factors to improve efficiency. Medium and large firms require to measure consumption by service with meters in order to increase efficiency, while small firms do not require it. 相似文献
5.
流域泥沙灾害与泥沙资源性的研究 总被引:5,自引:0,他引:5
泥沙灾害与泥沙资源性是流域泥沙的重要属性,二者在一定条件下可以相互转化。本文论述了泥沙淤积、泥沙冲刷、岸滩崩塌、山地崩塌与泥石流、粗沙淤积的土地沙化等泥沙灾害,指出泥沙灾害具有时空分布的不均匀性、渐变性或突发性、群发性、转化性及危害严重性等;流域泥沙资源化的主要途径包括填海造陆及造地、引洪淤灌、堤防淤临淤背、建筑材料、湿地形成(河流、湖泊与河口海岸)等,指出流域泥沙资源化及其优化配置既要解决思想观念、基本理论、目标效益等方面的问题,还要考虑与水资源联合配置问题。 相似文献
6.
通过百泉泉区天然状态与超采状态下的水环境对比分析,并对岩溶水补给量和开采量进行计算,阐述恢复邢台百泉泉水流量的可行性,随着“引朱济邢”和“南水北调”供水工程的实施,邢台百泉水生态环境的恢复将变为现实。 相似文献
7.
8.
太原精神病院污水处理系统改建为中水处理系统的工程设计 总被引:1,自引:0,他引:1
太原精神病医院将现有生活污水处理系统改建为中水回用系统,平均日处理水量100 m3.工程设计充分考虑了对原有设施的利用,生物处理单元采用生物接触氧化法.为减少污水提升次数,调节池设在生物处理单元之后.通过延长水力停留时间缓解水量、水质波动对沉淀、生物处理单元的不利影响,投入运行后效果良好. 相似文献
9.
龙口水利枢纽坝基岩体主要由奥陶系中统马家沟组(O2m2)灰岩组成,其中发育有多层软弱夹层。作为其中之一的钙质充填夹层,强度虽不很低,但由于处于坝基下的持力层内,间距不大,发育密集,产状平缓,是坝基浅层抗滑稳定的主要控制因素,因此,在大坝抗滑稳定分析时,应进行分析和研究。 相似文献
10.
铬渣的无害化处理和综合利用 总被引:13,自引:2,他引:11
铬渣产量大、毒性剧烈,是严重污染生态环境和危害人类健康的危险废物.本文介绍了铬渣各种无害化处理方法的解毒机理、工艺过程和应用实践,阐述了对铬渣进行综合利用的途径,并就铬渣的防治措施提出了建议. 相似文献