全文获取类型
收费全文 | 88061篇 |
免费 | 1960篇 |
国内免费 | 3篇 |
专业分类
管理学 | 12032篇 |
民族学 | 522篇 |
人才学 | 25篇 |
人口学 | 6547篇 |
丛书文集 | 505篇 |
理论方法论 | 9238篇 |
综合类 | 2060篇 |
社会学 | 40430篇 |
统计学 | 18665篇 |
出版年
2023年 | 508篇 |
2021年 | 561篇 |
2020年 | 1496篇 |
2019年 | 2195篇 |
2018年 | 2018篇 |
2017年 | 3085篇 |
2016年 | 2317篇 |
2015年 | 2039篇 |
2014年 | 2621篇 |
2013年 | 18792篇 |
2012年 | 2214篇 |
2011年 | 2002篇 |
2010年 | 1878篇 |
2009年 | 2140篇 |
2008年 | 1951篇 |
2007年 | 1730篇 |
2006年 | 1995篇 |
2005年 | 2186篇 |
2004年 | 2078篇 |
2003年 | 1808篇 |
2002年 | 1911篇 |
2001年 | 1885篇 |
2000年 | 1667篇 |
1999年 | 1585篇 |
1998年 | 1448篇 |
1997年 | 1296篇 |
1996年 | 1252篇 |
1995年 | 1281篇 |
1994年 | 1255篇 |
1993年 | 1236篇 |
1992年 | 1209篇 |
1991年 | 1142篇 |
1990年 | 1109篇 |
1989年 | 957篇 |
1988年 | 1056篇 |
1987年 | 930篇 |
1986年 | 823篇 |
1985年 | 1000篇 |
1984年 | 1072篇 |
1983年 | 963篇 |
1982年 | 897篇 |
1981年 | 830篇 |
1980年 | 777篇 |
1979年 | 829篇 |
1978年 | 747篇 |
1977年 | 672篇 |
1976年 | 631篇 |
1975年 | 609篇 |
1974年 | 492篇 |
1973年 | 411篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Implementing partial least squares 总被引:2,自引:0,他引:2
M. C. Denham 《Statistics and Computing》1995,5(3):191-202
Partial least squares (PLS) regression has been proposed as an alternative regression technique to more traditional approaches such as principal components regression and ridge regression. A number of algorithms have appeared in the literature which have been shown to be equivalent. Someone wishing to implement PLS regression in a programming language or within a statistical package must choose which algorithm to use. We investigate the implementation of univariate PLS algorithms within FORTRAN and the Matlab (1993) and Splus (1992) environments, comparing theoretical measures of execution speed based on flop counts with their observed execution times. We also comment on the ease with which the algorithms may be implemented in the different environments. Finally, we investigate the merits of using the orthogonal invariance of PLS regression to improve the algorithms. 相似文献
992.
Jeffrey S. Simonoff 《Statistics and Computing》1995,5(3):245-252
The standard approach to non-parametric bivariate density estimation is to use a kernel density estimator. Practical performance of this estimator is hindered by the fact that the estimator is not adaptive (in the sense that the level of smoothing is not sensitive to local properties of the density). In this paper a simple, automatic and adaptive bivariate density estimator is proposed based on the estimation of marginal and conditional densities. Asymptotic properties of the estimator are examined, and guidance to practical application of the method is given. Application to two examples illustrates the usefulness of the estimator as an exploratory tool, particularly in situations where the local behaviour of the density varies widely. The proposed estimator is also appropriate for use as a pilot estimate for an adaptive kernel estimate, since it is relatively inexpensive to calculate. 相似文献
993.
Ronald C. Wimberley 《The American Sociologist》1998,29(4):5-19
Applied sociology is basically what sociologists do for nonsociologists and sometimes for themselves. Applied sociology includes
the teaching of sociology as one of the liberating arts and sciences. It also involves the practice of sociology outside academia
in the public and private sectors. Either way, applied sociology needs support groups, and state sociological associations
need useful things to do beyond their traditional interests in academic teaching and research. Professional sociological associations,
and especially those that serve at the local, state level, can become important support groups for applied sociology. This
article suggests five types of applied sociology projects appropriate for state associations. These are volunteering applied
sociology; doing applied sociology through consulting; making the value of sociological applications more visible; identifying
applied sociology jobs for our baccalaureate, master's, and doctoral graduates; and helping to improve the socioeconomic outlook
for our academic colleagues and, in turn, ourselves. State associations provide an organizational base, proximate members,
and local opportunities for applying sociology.
Ron Wimberley, teaches sociological research methods and does research on the southern Black Belt and other topics. He also
attempts applied sociology through volunteer work, consulting, and occasional leaves from his university position. Catherine
Harris of Wake Forest University is appreciated for suggesting the topic. The author is responsible for the views expressed
in the article. 相似文献
994.
Barry V. Johnston 《The American Sociologist》1998,29(3):26-42
The history of sociology is marked by periods of theoretical pluralism and hegemony. Their interplay has resulted in the slow
and uneven development of the discipline. Today, however, bodies of theory and practice have become so diverse that many scholars
worry that sociology is in a state of disintegration. The theoretical career of Talcott Parsons provides a microcosm in which
to explore similar processes. Building on the success of The Structure of Social Action, Parsons led a movement that transformed Harvard's Department of Sociolgy into the Department of Social Relations. There
he attempted a grander, but failed synthesis in Toward A General Theory of Action. His case provides a situation in which to explore features of disciplinary integration and fragmentation. The comparison
stimulates one to fashion an informed sense of whether sociology is now facing its latest crisis or may be in the process
of decomposition as a corpus of study.
This research was supported by grants from the American Sociological Association's Fund for the Advancement of the Discipline
and by Indiana University Northwest through a sabbatical leave. 相似文献
995.
Abstract Many race-specific differences in health outcomes that have been observed in previous research have been attributed to class and racebased group differences which either facilitate or constrain health opportunities and behaviors. These include such variables as different rates of poverty, health insurance coverage, and access to medical care. However, these relationships have been inadequately examined in rural communities where minority status may be even more detrimental to health than in urban areas, due to various constraints on access to health care. We present an analysis that assesses the effects of community, family structure, sociodemographic, and medical care variables on self-reported health status among Hispanics, Mrican Americans, and non-Hispanic whites in six rural communities in Florida. Community structural characteristics had a significant effect on self-reported health, as did some of the measures of how respondents “experience” community. These relationships held even when other sets of variables were added to the models. Family/household characteristics and sociodemographic and medical care variables were less important in explaining self-reported health status. These findings suggest that community continues to be important in explaining differences in health status in rural areas. 相似文献
996.
Abstract The alternative agriculture paradigm has been a useful device to both define and direct a social movement toward a more sustainable agriculture. But because that paradigm was defined by male movement leaders, it reflects their gendered perspective and may be lacking elements that make it more useful for both women and men. In-depth interviews of women involved in sustainable farming organizations and on family farms experimenting with new practices validated the elements of the Beus and Dunlap paradigm: independence, decentralization, community, harmony with nature, diversity, and restraint, but also suggested the addition of two other elements that the women identified as part of an alternative agriculture vision: quality family life and spirituality. The highly gendered nature of agriculture in the V.S. and Canada, where male identity is highly conflated with the role of farmer in the conventional paradigm, may make it more difficult for men who have just joined the' movement to articulate the aspects of quality family life and spirituality which the women saw as critical. 相似文献
997.
Thomas K. Rudel 《Rural sociology》1998,63(4):533-552
Abstract Environmental social scientists have recently begun to use the term 'forest transition' to describe how forest cover changes as economic development occurs in nations. The hypothesized transition occurs as follows. An initial surge in economic activity in impoverished societies spurs deforestation, but as economic activity continues to intensify and cities grow larger, a 'turnaround' occurs, and deforestation gives way to reforestation. This paper uses cross-national data from five successive surveys of world forest resources to assess this empirical claim. A turnaround in forest cover trends does occur in a significant number of nations. The paper also evaluates two explanations for the turnaround, a wood scarcity hypothesis derived from microeconomic theory and an industrialization hypothesis linked to central place theory. It finds period specific support for the industrialization hypothesis. The paper concludes with a brief discussion of the implications of these findings for proposals to alleviate the biodiversity crisis through programs of reforestation. 相似文献
998.
Abstract "Subsistence" and "informal economy" are contrasted in their utility as sociological concepts and their ability to explain a variety of activities in two rural Mississippi Delta communities. Literature on subsistence stresses that the desired outcome of participation is not an increase in income but the social rewards of participation itself. Two underlying dimensions of participation in these activities are documented through the literature and through a confirmatory factor analysis of empirical data: life-style choice and economic strategy. These were constructed into indexes and examined individually and in combination as dependent variables using regressors at the community, household, and individual levels. Community ties were weakly associated with participation in such activities. Whites and those with higher incomes participated more in lifestyle choice oriented activities. Participation in general was statistically related to households needing less weekly income and being of larger size. Potential connections with persistent rural poverty are discussed. 相似文献
999.
The medical community, along with other government agencies, has created its own frame of environmental illness. This frame has been generally accepted by the American public. In this paper we discuss framing in general and the factors related to how the environmental illness frame has been constructed and maintained. We offer a brief history of the medical institution and illustrate the frame with its definitions of environmental illness. Qualitative data from a study of Oak Ridge, a contaminated community located in Tennessee, are examined to analyze the consequences of challenging the environmental illness frame. Implications for future research are discussed. 相似文献
1000.
Thomas K. Kenemore 《Child and Adolescent Social Work Journal》1998,15(4):249-249