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   13882篇
  免费   98篇
管理学   2045篇
民族学   128篇
人才学   1篇
人口学   2690篇
丛书文集   31篇
理论方法论   821篇
综合类   306篇
社会学   6250篇
统计学   1708篇
  2023年   18篇
  2021年   23篇
  2020年   54篇
  2019年   77篇
  2018年   1714篇
  2017年   1732篇
  2016年   1149篇
  2015年   114篇
  2014年   112篇
  2013年   722篇
  2012年   405篇
  2011年   1239篇
  2010年   1117篇
  2009年   841篇
  2008年   921篇
  2007年   1087篇
  2006年   80篇
  2005年   311篇
  2004年   335篇
  2003年   285篇
  2002年   196篇
  2001年   89篇
  2000年   90篇
  1999年   69篇
  1998年   58篇
  1997年   58篇
  1996年   72篇
  1995年   61篇
  1994年   54篇
  1993年   50篇
  1992年   45篇
  1991年   52篇
  1990年   42篇
  1989年   40篇
  1988年   66篇
  1987年   57篇
  1986年   26篇
  1985年   39篇
  1984年   46篇
  1983年   57篇
  1982年   32篇
  1981年   35篇
  1980年   29篇
  1979年   34篇
  1978年   39篇
  1977年   31篇
  1976年   35篇
  1975年   28篇
  1974年   18篇
  1972年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
371.
Direct applications of remote sensing thermal infrared (TIR) data in landscape ecological research are rare due to limitations in the sensors, calibration, and difficulty in interpretation. Currently there is a general lack of methodology for examining the relationship between land surface temperatures (LST) derived from TIR data and landscape patterns extracted from optical sensors. A separation of landscapes into values directly related to their scale and signature is a key step. In this study, a Landsat ETM+ image of Indianapolis, Unites States, acquired on June 22, 2000, was spectrally unmixed (using spectral mixture analysis, SMA) into fraction endmembers of green vegetation, soil, high albedo, and low albedo. Impervious surface was then computed from the high and low albedo images. A hybrid classification procedure was developed to classify the fraction images into seven land use and land cover (LULC) classes. Using the fractional images, the landscape composition and pattern were examined. Next, pixel-based LST measurements were correlated with the landscape fractional components to investigate LULC based relationships between LST and impervious surface and green vegetation fractions. An examination of the relationship between the LULC and LST maps with landscape metrics was finally conducted to deepen understanding of their interactions. Results indicate that SMA-derived fraction images were effective for quantifying the urban morphology and for providing reliable measurements of biophysical variables. LST was found to be positively correlated with impervious surface fraction but negatively correlated with green vegetation fraction. Each temperature zone was associated with a dominant LULC category. Further research should be directed to the theoretical and applied implications of describing such relationships between LULC patterns and urban thermal conditions.
Dengsheng LuEmail:
  相似文献   
372.
Publishing performance information about local public services,an increasing trend in many Organisation for Economic Co-operationand Development countries, matters politically because it hasan effect on incumbent local governments' electoral support.Voters are able to use performance information to punish orreward incumbents in the elections that follow their publication,which may fill a gap in the chain of accountability betweenvoters and governments. We model the introduction of publishedComprehensive Performance Assessments of local authorities inEngland, which make summary information about performance availableto voters, as a "shock" to the relationship between voters andincumbents. Controlling for an unpublicized measure of performancechange over time, change in the local tax level, change in localeconomic conditions, and whether the local incumbent is theparty of the incumbent government at the national level, wefind negativity bias. Incumbents in local authorities in the"poor" performance category experience a substantial reductionin aggregate vote share at the election following publication,but there is no similarly sized reward for those in the highestperformance category.  相似文献   
373.
This paper reviews the main bodies of contemporary urban sustainability theory. From this analysis, two underpinning paradigms of urban sustainability are identified: (1) The ‘Human Exemptionalism Paradigm’ (HEP), which emphasizes the ability of humans to overcome environmental problems—see Urban Sociology, Urban Ecology, Urban Geography, Urban Psychology and Political Economy; and (2) The ‘New Ecological Paradigm’ (NEP), which emphasizes the criticality of ecological limits to human progress—see Urban Metabolism, Energy/Emergy Analysis and Ecological Footprinting. Each of these approaches is critically reviewed, highlighting their main assumptions, theoretical and practical foci. It is argued in the paper that if the related issues of urban sustainability and development are to be progressed, there needs to be: (1) a greater maturation of the NEP approaches, which are ‘relative newcomers’ to the area of urban theory; and (2) greater integration and dialogue between the HEP and NEP approaches to urban sustainability than has hitherto been the case.
Murray G. PattersonEmail:
  相似文献   
374.
Using a spatially extensive urban database constructed from the Maryland Biological Stream Survey (MBSS), we describe the relationships of nutrients in small-order streams to eight defined categories of percent catchment urbanization, correlations between chloride and conductivity in urban streams, and relationships between nutrients and chloride with two Maryland-specific indices of biotic integrity for benthic macroinvertebrates and fish assemblages. Stream nutrients become elevated with increasing percent catchment urbanization, followed by increases in all four measured nitrogen species and total phosphorus at catchment urbanization levels greater than 10%. There was a strong collinear relationship (r 2 = 0.90) between chloride and conductivity (trimeans) across all eight urbanization classes, where Cl (mg/L) = −0.397 + 0.188*conductivity (μS/cm). Critical values for all water quality parameters with the two Maryland biological indices were derived using quantile regression, with significant regressions developed for 11 of 16 water quality parameters and the two biotic indices. For nitrate (NO3-N), the critical thresholds between fair and poor stream quality for the two Maryland biological indices were 0.83 mg/L (benthic macroinvertebrate assemblages) and 0.86 mg/L (fish assemblages). Increasing stream nutrient and chloride levels, associated with widespread catchment urbanization intensity, now affect many small streams in Maryland, with implications for decreasing water quality in major tributaries and the Chesapeake Bay.  相似文献   
375.
The theoretical basis behind consultancy does not match its importance to the economy. Although theory building research has been advanced since the 1990s, it still remains fragmentary. The impact of these consulting theories on practice has therefore been limited. This paper provides a contribution to this recent field of research. Based on the Social Systems Theory by Luhmann, a model outlining the impact of consultancy is presented. Three empirical cases outline the usefulness of the presented model in practice.  相似文献   
376.
In the public sector, Canadian governments intervene frequently in labor disputes by suspending collective bargaining and curtailing legal strikes. Previous research has focused on the contours of government intervention, such as its overall effects on collective bargaining and strikes. The discussion highlights one actor, a government, restricting the behavior of another actor, a union, using legislation and policy making. As a result, we know less about more micro-level elements and implications of the process of government intervention. I address these themes using a detailed case study of the Alberta Teachers’ Association and the strikes it coordinated in 2002.
Yonatan ReshefEmail:
  相似文献   
377.
We test the human capital interpretation of the experience-earnings profile. Does the upward sloping portion of the experience-earnings profile reflect on-the-job training which in turn causes the experience-productivity profile to slope upwards, or do purely contractual factors determine the nature of life-cycle earnings. Herein, we provide additional evidence on the relationship between productivity and earnings by examining earnings differentials in the UK academic labor market for economists. Using a test first suggested by Mincer, we find that the empirical results are consistent with human capital theory. We find that, although the positive relationship between earnings and experience persists when individual productivity measures are included in the salary equations for lecturers and senior lecturers, the positive relationship becomes statistically insignificant when the same productivity measures are included in the salary equations for professors. For lecturers and senior lecturers, the experience-salary profile properly reflects the structure of the national pay scale rather than variations in individual research productivity. At the professor level, where individual salaries are not determined by a pay scale, the data support the human capital explanation of the positive experience-earnings profile.
Robert J. NewmanEmail:
  相似文献   
378.
379.
Using meta-analysis, we find a consistent positive correlation between emotion recognition accuracy (ERA) and goal-oriented performance. However, this existing research relies primarily on subjective perceptions of performance. The current study tested the impact of ERA on objective performance in a mixed-motive buyer-seller negotiation exercise. Greater recognition of posed facial expressions predicted better objective outcomes for participants from Singapore playing the role of seller, both in terms of creating value and claiming a greater share for themselves. The present study is distinct from past research on the effects of individual differences on negotiation outcomes in that it uses a performance-based test rather than self-reported measure. These results add to evidence for the predictive validity of emotion recognition measures on practical outcomes.
Hillary Anger ElfenbeinEmail:
  相似文献   
380.
I investigate the earnings differentials among union and nonunion seafarers, across seafarer occupations, and with respective to other transport operatives. The empirical results suggest that the union and nonunion weekly earnings of captains/mates are comparable, and the union earnings gap for sailors/deckhands is positive. The union (nonunion) weekly earnings of captains/mates are 14.7 (30.5) percent greater than those of sailors/deckhands; the union weekly earnings of captains/mates (sailors/deckhands) are 12.6% greater (9.5% less) than those of truck drivers; and the nonunion weekly earnings of captains/mates (sailors/deckhands) are 33.0% greater (6.2% less) than those of truck drivers. The sailor/deckhand and truck driver earnings differentials are contrary to the general belief that the earnings of truck drivers are less than those of other operative occupations involved in transporting intermodal cargo.
Wayne K. TalleyEmail:
  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