全文获取类型
收费全文 | 15984篇 |
免费 | 307篇 |
专业分类
管理学 | 2148篇 |
民族学 | 84篇 |
人才学 | 2篇 |
人口学 | 1380篇 |
丛书文集 | 104篇 |
教育普及 | 2篇 |
理论方法论 | 1503篇 |
综合类 | 373篇 |
社会学 | 8077篇 |
统计学 | 2618篇 |
出版年
2023年 | 83篇 |
2021年 | 99篇 |
2020年 | 272篇 |
2019年 | 302篇 |
2018年 | 338篇 |
2017年 | 510篇 |
2016年 | 408篇 |
2015年 | 317篇 |
2014年 | 360篇 |
2013年 | 2539篇 |
2012年 | 530篇 |
2011年 | 431篇 |
2010年 | 295篇 |
2009年 | 328篇 |
2008年 | 354篇 |
2007年 | 363篇 |
2006年 | 304篇 |
2005年 | 452篇 |
2004年 | 392篇 |
2003年 | 347篇 |
2002年 | 365篇 |
2001年 | 407篇 |
2000年 | 368篇 |
1999年 | 364篇 |
1998年 | 261篇 |
1997年 | 239篇 |
1996年 | 262篇 |
1995年 | 222篇 |
1994年 | 239篇 |
1993年 | 228篇 |
1992年 | 277篇 |
1991年 | 267篇 |
1990年 | 237篇 |
1989年 | 240篇 |
1988年 | 218篇 |
1987年 | 206篇 |
1986年 | 213篇 |
1985年 | 201篇 |
1984年 | 242篇 |
1983年 | 225篇 |
1982年 | 193篇 |
1981年 | 158篇 |
1980年 | 159篇 |
1979年 | 189篇 |
1978年 | 153篇 |
1977年 | 141篇 |
1976年 | 115篇 |
1975年 | 123篇 |
1974年 | 115篇 |
1973年 | 103篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
831.
Urban forest cover of the Chicago region and its relation to household density and income 总被引:12,自引:0,他引:12
Urban forests and herbaceous open space play a vital role in the environmental and aesthetic health of cities, yet they are rarely identified in land-use inventories of urban areas. To provide information on urban forests and other vegetative land cover in Illinois cities, Landsat Thematic Mapper (TM) data from June 27, 1988, were classified for the Chicago metropolitan region (9,717 km2). Ten land-cover classes were identified, including two types of forestland (occupying 5.8% of the total area), residential land with trees (14.6%) or without trees (7.8%), cropland (37.5%), two types of grassland (7.7%), urban with impervious surfaces (23.1%), water (1.6%), and miscellaneous vegetation (2.1%). Correlation analyses indicated that household income and household density are strongly related to land covers in the region, particularly those with tree cover and urbanized land. Population changes for 1980–1985 and 1985–2010 (projected) show a pattern of increasing density in the urbanized zone concurrent with continued urban sprawl, primarily into current cropland. 相似文献
832.
Siting Noxious Facilities: A Test of the Facility Siting Credo 总被引:2,自引:0,他引:2
Over the past decade it has become increasingly difficult to site noxious facilities, despite the fact that there is a growing need to do so. To address this problem, a set of guidelines for a fairer, wiser, and more workable siting process—the Facility Siting Credo—was developed during a National Facility Siting Workshop in 1990. This paper presents an empirical test of these guidelines. A questionnaire based on the Credo was completed by stakeholders in 29 waste facility siting cases, both successful and unsuccessful, across the United States and Canada. Using an independent determination of outcome (success), a preliminary ranking of the importance of various Credo principles was obtained. The data reveal that establishing trust between the developer and host community is an important factor in facilitating the siting process. The siting process is most likely to be successful when the community perceives the facility design to be appropriate and to satisfy its needs. Public participation also is seen to be an important process variable, particularly if it encourages a view that the facility best meets community needs. Moreover, a siting process where communities volunteer to host facilities is an approach that holds promise for meeting many of these key success criteria. 相似文献
833.
What Determines Trust in Information About Food-Related Risks? Underlying Psychological Constructs 总被引:12,自引:0,他引:12
Trust in risk information about food related-hazards may be an important determinant of public reactions to risk information. One of the central questions addressed by the risk communication literature is why some individuals and organizations are trusted as sources of risk information and others are not. Industry and government often lack public trust, whereas other sources (for example, consumer organizations, the quality media, medical doctors) are highly trusted. Problematically, previous surveys and questionnaire studies have utilized questions generated by the investigators themselves to assess public perceptions of trust in different sources. Furthermore, no account of the hazard domain was made. In the first study reported here, semistructured interviewing was used to elicit underpinning constructs determining trust and distrust in different sources providing food-related risk information ( n = 35). In the second study, the repertory grid method was used to elicit the terminology that respondents use to distinguish between different potential food-related information sources ( n = 35), the data being submitted to generalised Procrustes analysis. The results of the two studies were combined and validated in survey research ( n = 888) where factor analysis indicated that knowledge in itself does not lead to trust, but that trusted sources are seen to be characterised by multiple positive attributes. Contrary to previous research, complete freedom does not lead to trust—rather sources which possess moderate accountability are seen to be the most trusted. 相似文献
834.
This paper integrates prior research on strategic leadership by building on the concept of alignment to explain the performance impact of top managers. Using the Miles and Snow (1978) typology as a theoretical framework, several hypotheses are tested on a sample drawn from three distinct industries. The results show that organizations that are able to achieve an alignment between managerial characteristics and strategic direction perform better than firms where such an alignment is absent. Further, it was found that the strategy-manager match explains a greater proportion of variance in performance than industry membership, organizational age and firm size. Taken together, these findings provide persuasive evidence about the impact that an organization's leaders exert in driving performance outcomes and demonstrates the validity of the administrative dimension of the Miles and Snow typology. 相似文献
835.
The paper deals with optimal allocation of a given amount of advertising expenditure among various sales districts. It applies dynamic programming to arrive at the optimal policy regarding such allocation. The basic model is that of Zentler and Ryde which heretofore has been solved using a graphical method. The optimal solution is illustrated with an example. 相似文献
836.
837.
Discourses constructed to represent lesbians and gay men in the public sphere generate an essentialist identity which is both necessary and damaging. Legislative debate illustrates the production of a constrictive and homogeneous identity rejected by many gay/lesbian scholars and activists. Discussion of the rhetorical power of identity claims has produced alternative stances toward variant sexuality. This discussion can be advanced by challenging dominant constructions of civil rights and the public sphere. 相似文献
838.
Hopper GR 《Population and development review》1999,25(3):443-477
Systematic and critical evaluation, using food balance sheets, census population data, government surveys, food composition statistics, and estimates of the population's biological requirements, shows that the realized improvements in food supplies in India of the past five decades, while beneficial, have been insufficient to meet the nutritional needs of the average person in a population that grew from less than 350 million to nearly one billion during this period. The improvements also fall significantly short of meeting the needs of the clinically malnourished. Present per capita dietary energy intakes range from as high as 95 percent to as low as 50 percent of daily requirements. Additionally, comparison of past and present diets shows that as the composition of the diet has changed with time, its nutritional quality for many has deteriorated despite an apparent increase in overall food quantity. This has come about from changes in the production system that have emphasized wheat and rice crops at the expense of more nutritional pulses and coarse grains, and from widespread poverty that leaves high-quality animal foods beyond the means of most. 相似文献
839.
This study expands immigrant social network theory and examined employment patterns in the garment industry in Los Angeles, California, among Latino workers employed by Asian immigrant entrepreneurs. The study determined that a large percentage of immigrant employees found their jobs through the immigrant economy. Entrepreneurship increased the supply of local jobs and expanded the economy at destination at no expense to natives. Immigrant entrepreneurs bought firms from nonimmigrant owners or started new ones with an immigrant labor supply. Massey's index is flawed due to its exclusion of the role of entrepreneurs. Migration networks facilitate entrepreneurship, but some ethnic groups have fewer entrepreneurs, such as Mexicans and Central Americans. A 1993 Los Angeles survey identified 3642 garment factories in its county. Mean employment was 27.1 persons. The garment industry was the 4th largest industry in the area in 1996, with 98,700 employees. It represented 6% of all wage and salary employees in the City and 5.5% of the immigrant labor force in the County in 1990. 93% of garment workers in 1990 were immigrants. It is estimated that 51% of garment factory owners were Asians; most employees were Latinos. Census figures on sewing machine operators indicated 47.3% of owners were Whites and 42.45 were Asians. 53.3% of employees were other ethnic groups, 14.5% were Asians, and 32.2% were Whites. It is estimated that 47.2% of total employment was due to the immigration economy. 71.5% of the total employment in the garment industry was in the immigrant sector. 相似文献
840.
This study examined the industrial division of labor among immigrants and in-migrants in the Los Angeles, California, metropolitan area. It addresses debates about channeling of new arrivals into jobs among similar ethnic groups and human capital views. Data were obtained from the 1990 Census on resident native-born, resident foreign-born, in-migrants, and recent immigrants who arrived during 1985-90. Light and Rosenstein's (1995) concepts of groups and their resources were used to organize ideas about ethnic networks and their effectiveness in channeling migrant workers into 15 industrial sectors. Sectoral differences were revealed with the familiarity index of dissimilarity. Findings reveal that social networks were the strongest for Koreans, who supplied work for recent arrivals in the same sectors as Korean-born residents, regardless of education. Mexican new arrivals were less likely to work in the same sectors as their resident Mexican counterparts. Mexican networks placed new arrivals in durable manufacturing in the 1960s and 1970s when it was a key source of employment. By the 1980s and 1990s, the economy shifted and employment went down in durable manufacturing. Mexicans thus found employment elsewhere. Native White and Black in-migrants had the strongest channeling into same sector jobs. This is attributed to the small streams, the ability of the labor market to absorb these workers, and the availability of job vacancies among native out-migrants. Filipino migrants had similar patterns as Whites and Blacks. Mexican and Central American residents had more inter-ethnic competition over jobs than Whites or Blacks. 相似文献