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   377篇
  免费   20篇
  国内免费   4篇
财政金融   18篇
工业经济   17篇
计划管理   92篇
经济学   57篇
综合类   40篇
运输经济   8篇
旅游经济   9篇
贸易经济   68篇
农业经济   52篇
经济概况   40篇
  2024年   1篇
  2023年   2篇
  2022年   9篇
  2021年   9篇
  2020年   17篇
  2019年   12篇
  2018年   8篇
  2017年   13篇
  2016年   12篇
  2015年   11篇
  2014年   28篇
  2013年   40篇
  2012年   22篇
  2011年   39篇
  2010年   39篇
  2009年   29篇
  2008年   30篇
  2007年   16篇
  2006年   20篇
  2005年   10篇
  2004年   7篇
  2003年   7篇
  2002年   4篇
  2001年   6篇
  2000年   4篇
  1999年   2篇
  1996年   3篇
  1993年   1篇
排序方式: 共有401条查询结果,搜索用时 31 毫秒
1.
[目的]利用遥感蒸散数据快速评价农田年度灌溉水平,及时获取基本农田建设成效,为农田灌溉设施分区建设提供参考。[方法]以黑龙江省海伦市为研究区,MOD16蒸散产品为数据源,计算有效灌溉量、灌溉需水量和作物缺水指数,分别对研究区2013年的旱地和水田灌溉水平进行评价,并将评价结果与农田水利设施作用分值图进行叠加分析,在此基础上进行基本农田灌溉设施建设分区。[结果]2013年海伦市耕地灌溉水平整体较高,区域间建设水平差别较大,可划分为4个级别。其中1级和2级灌溉水平的地块面积比例可达78.06%,地域分布上看,北部、西部、中部乡镇灌溉水平较高,东南部乡镇灌溉水平相对较低。叠加得出8种组合类型,分为设施修建型、设施提升型和设施维护型3种分区类型。[结论]研究为高标准农田建设提供了更详细的农田灌溉水平评价方法和更具差别化的农田灌溉设施建设策略。  相似文献   
2.
The extant literature runs short in understanding openness of innovation regarding and the different pathways along which internal and external knowledge resources can be combined. This study proposes a unique typology for outside‐in innovations based on two distinct ways of boundary spanning: whether an innovation idea is created internally or externally and whether an innovation process relies on external knowledge resources. This yields four possible types of innovation, which represent the nuanced variation of outside‐in innovations. Using historical data from Canada for 1945–1980, this study unveils different implications of these innovation types for different levels of innovation novelty. Copyright © 2016 ASAC. Published by John Wiley & Sons, Ltd.  相似文献   
3.
Are museums, galleries and cultural institutions (MGC) educational institutions or accommodations of leisure market? The aim of the present study is to understand why people visit MGCs through analysing a potential link between internet use types and MGC visits. Internet use is categorized into three types: independent activities, recreational activities and social activities. The empirical results indicate that internet use for recreational activities is negatively related to MGC visits, while internet use for independent activities is positively related to MGC visits. The findings suggest that MGCs are expected to provide visitors with educational experience rather than with social or recreational experience.  相似文献   
4.
We investigates the sentiment-driven trading behaviour of the four types of investors in the London office market, i.e. UK institutional investors, UK private investors, UK listed real estate companies/Real Estate Investment Trust (REIT)s and overseas investors. In addition, we examine the relationship between investor sentiment and property performance. Related indices are calculated to examine the existence of herding behaviour of different investors. We find that UK private investors follow a contrarian strategy to UK institutional investors and listed real estate companies/REITs and enter/exit the market at different points of time. UK institutional investors tend to follow the sentiment of UK listed real estate companies/REITs and overseas investors with lags. There is no evidence that overseas investors rely upon the sentiment of UK specialised property investors in their decision-making. We find the sentiment of different investors is influenced differently by market fundamentals. Yield and rental growth rate have significant impact on trading activity of overseas investors, but not on other investors. The stock market return and securitised real estate return have significant impact on the trading activity of UK institutional investor and overseas investor, but have no significant influence on the trading behaviour of UK private investor and listed real estate company/REIT.  相似文献   
5.
[目的]土地利用规划和城市规划的用地地块,在实际使用过程中,都会不同程度与规划用途产生差异,如何把握规划的实施程度是土地管理中的一个重要问题。[方法]在大数据时代的背景下,通过对网络大数据可以真实地反映城市地块的真实使用状况。研究采用OSM(Open Street Map),对研究区进行城市地块的划分,形成街区尺度的城市地块。采用POI(Point of Interest)数据,建立了POI分类与城市用地分类的映射关系,计算了不同类型的POI数据的频数密度和类型比例,形成基于POI的城市地块用地类型识别方法,对研究区的城市地块进行土地利用现状识别。识别结果与第二次土地调查分类结果进行对比,验证方法的可行性。[结果]从泸州市的实证结果看,基于POI数据的城市地块识别结果与基于地籍数据的城市地块识别结果存在很大的差别。地籍数据主要是表针城市地块中不同实体的土地利用状况,两种数据采集的标准和表达的意义都不同,因此造成结果存在较大的差异性。[结论]研究认为,POI点有准确的空间位置信息和丰富的属性信息,主要是表征城市地块中不同实体的真实使用状况,可以较准确地判定快速发展的城市进程中的城市用地类型,能较为真实反映城市地块的现实使用状况,但也要注意POI数据在实际应用中存在的缺陷和不足。  相似文献   
6.
[目的]精确测度村级多维贫困以及划分贫困类型,是当前提高贫困识别精准度,进一步推进农村精准脱贫的战略需求。[方法]文章基于重庆市1 919个市级贫困村的调研数据,构建地理资本视角下村域多维贫困测度指标体系,并采用多维贫困测度模型、指标贡献度模型和最小方差方法系统揭示了重庆市贫困村多维贫困程度、贫困类型及其空间分布特征。[结果](1)重庆市贫困村多维贫困程度呈两端大中间小的"哑铃状"结构,贫困程度极化特征显著,区域发展具有不平衡性。空间分布上,贫困村多维贫困程度呈从渝东北、渝东南分别向渝西地区逐渐减轻的特征,贫困村多维贫困程度存在明显的地域性差异;(2)重庆市贫困村贫困类型主要分为单资本缺失型、双资本缺失型、三资本缺失型、四资本缺失型4个类型,其占比分别为9.07%、20.27%、66.91%、3.75%,三资本缺失型是最主要的贫困类型。[结论]重庆市贫困村致贫因素复杂多样,需要根据各自的贫困特征,因地制宜地开展差别化的帮扶工作。科学推进精准扶贫战略,力争实现2020年全面脱贫。  相似文献   
7.
基于主体功能定位的湖北省县域乡村性空间分异研究   总被引:1,自引:0,他引:1  
[目的]确立与主体功能区定位相协调的乡村发展类型与乡村政策,是促进城乡融合、乡村振兴的重要措施。[方法]以湖北省县域为空间单元,构建乡村性评价指标体系,并基于三次产业的产值结构,划分县域的乡村发展类型。[结果](1)2016年湖北省县域乡村性指数相对较高,乡村性呈现出东低西高的空间分布格局。乡村发展类型可划分为农业主导型、工业主导型、商旅服务型和均衡发展型,分别占县域总数的25.29%、16.1%、10.71%和48.28%。(2)重点开发区的乡村类型以工业主导型和商旅服务型为主,乡村类型主要是城镇化和工业化带动,市场、资本推动力和农民的自主选择突出;农产品主产区和重点生态功能区的乡村类型均以农业主导型和均衡发展型为主,不同的是农产品主产区的农业自然和生产条件优越、农耕文化根植,农业政策扶植,乡村类型是由农业现代化和产业化推动;重点生态功能区乡村类型受资源环境约束、经济基础及行政干预的推动。[结论]三大主体功能区下的乡村类型及驱动机制存在差异,并提出不同乡村振兴发展的政策建议。  相似文献   
8.
The distinct urbanization process of China has attracted worldwide attention because of its impressive speed, massive scale, and policy intervention. However, the interrelationship between urban expansion and government policies is still not well understood. The Pearl River Delta Urban Agglomeration of China is the first national pioneering urbanization area since the implementation of the policy “Reform and Opening-up” in the late 1970s. Here we compared the spatial and temporal patterns of urbanization in two leading cities of the Pearl River Delta (i.e., Guangzhou and Shenzhen, the provincial capital and the first Special Economic Zone of China, respectively) from 1975 to 2015, using Landsat data integrated with urban growth and landscape metrics analysis, and examined possible footprints of major economic and urbanization policies. Our results illustrated that urban land areas in both Guangzhou and Shenzhen have experienced magnificent annual growth rates at 8.1% and 11%, respectively between 1975 and 2015. On average, Shenzhen witnessed substantially higher urban growth rate than Guangzhou during the past four decades, particularly in the initial period (1978–1990) when the Reform and Opening-up policy was launched and Shenzhen was designated as the first Special Economic Zone in China in the late 1970s. However, the speed of urban expansion in Shenzhen became considerably lower than Guangzhou from 2005 to 2015, subject to physical conditions and a series of urban land use policies. Both cities showed a generally similar dynamics of urban growth forms with leapfrogging as the predominant type of urban growth at first and then edge-expansion while the contribution of infilling in Shenzhen was higher than that in Guangzhou, especially since 2005. The urbanization processes characterized by landscape and urban growth metrics revealed that a diffusion-coalescence-diffusion-coalescence process was identified for Guangzhou, while Shenzhen was generally consistent with the diffusion-coalescence urban growth hypothesis.  相似文献   
9.
This study aims to investigate the hotel selection differences among different types of travellers through online hotel reviews. Specifically, the study performs a detailed examination of the differences in hotel key factors, criterion importance and selection results among five types of travellers, namely, business, couples, families, friends and solo. Using a sample of 194,885 online reviews on TripAdvisor.com, this study identifies the hotel key factors and criterion importance by employing the term frequency-inverse document frequency algorithm and Word2Vec algorithm. Additionally, a bounded rationality behavioural decision support model with picture fuzzy information is proposed to address hotel selection problems for different traveller types. Our results suggest that different types of travellers present differences in hotel key factors, criterion importance and selection results. However, families and friends have similar hotel selection results. This study can serve as a reference for hotel managers in understanding traveller preferences and for tourism website optimisation.  相似文献   
10.
目的:通过微生物和理化指标检测,对比分析不同类型水净化前后的水质,为居民选择合理健康的饮用水提供参考.方法:取5种不同处理方式的水进行微生物、理化指标检测.具体项目为菌落总数、总大肠菌群、大肠埃希氏菌、耐热大肠菌群、pH、溶解性总固体、总硬度、砷、汞、铅、镉、硫酸盐、氯化物、氟化物和硝酸盐.结果:自来水、净化后的自来水15项指标都合格;井水共有6项指标不合格,分别是菌落总数、总大肠菌群、大肠埃希氏菌、耐热大肠菌群、溶解性总固体和总硬度;净化后井水、直饮水的菌落总数不合格.结论:井水水质卫生质量差,被粪便污染,水硬度高.净化后的水水质较好,但在净化、运输等过程中要防止二次污染.水质达到标准规定的前提下,在日常生活中人们可以根据自身对各类物质的需求,交替饮用自来水、净化水、直饮水和凉白开.  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