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   11809篇
  免费   298篇
管理学   1709篇
民族学   53篇
人才学   1篇
人口学   1205篇
丛书文集   62篇
教育普及   1篇
理论方法论   1045篇
现状及发展   1篇
综合类   137篇
社会学   5657篇
统计学   2236篇
  2023年   77篇
  2021年   60篇
  2020年   172篇
  2019年   228篇
  2018年   271篇
  2017年   376篇
  2016年   299篇
  2015年   189篇
  2014年   253篇
  2013年   2056篇
  2012年   400篇
  2011年   331篇
  2010年   277篇
  2009年   262篇
  2008年   293篇
  2007年   285篇
  2006年   269篇
  2005年   273篇
  2004年   261篇
  2003年   233篇
  2002年   265篇
  2001年   292篇
  2000年   307篇
  1999年   277篇
  1998年   196篇
  1997年   178篇
  1996年   176篇
  1995年   171篇
  1994年   138篇
  1993年   160篇
  1992年   177篇
  1991年   150篇
  1990年   167篇
  1989年   187篇
  1988年   156篇
  1987年   144篇
  1986年   151篇
  1985年   176篇
  1984年   174篇
  1983年   165篇
  1982年   124篇
  1981年   112篇
  1980年   109篇
  1979年   140篇
  1978年   92篇
  1977年   94篇
  1976年   89篇
  1975年   84篇
  1974年   83篇
  1973年   75篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
Quality and sustainability are both socially constructed, ambiguous terms, but they have not been heretofore linked in the rural studies literature. The “quality turn” has received particular attention from researchers for its potential to organize linkages among various forces in agrofood systems, providing more income to producers by appealing to affluent, reflexive consumers. A distinct line of rural research has attended to the challenge of agro-environmental pollution and regulation, but this research trajectory has been subsumed under the broader paradigm of sustainability. This article seeks to contribute to discussions about quality in the agrofood sector by analyzing the potential of fusing rural resource protection practices with place-based marketing of enhanced quality, drawing from an empirical study of the California winegrape industry. In several California commodities, agroecological partnerships are becoming the chief vehicle for extending sustainable agricultural practices. California's winegrape farmers have undertaken more partnerships to greater effect than those of any other US crop, and they are now discursively linking their sustainable farming practices, environmental quality, and wine quality. This marks a new linkage of two heretofore discrete social imaginaries. This article argues that “quality” is a term that can conceptually link increasing consumer demand for differentiated product taste with increasing regulatory pressure for environmental protection. Synergistic benefits from such a linkage have the potential to strengthen rural development initiatives. Making progress toward sustainability requires collective action on the part of producers, and in some commodities, may mesh well with efforts to enhance foodstuff quality.  相似文献   
22.
The theory of incapacitation involves reducing an offender's ability or capacity to commit further crimes. Capital punishment accomplishes this goal. An executed murderer never murders again. However, we do not execute all murderers, only capital murderers. This policy produces several research questions. Do capital murderers present a special risk to society? Are capital murderers more likely to murder or commit other violent crimes again than other murderers or the average citizen? To answer these questions, many states require a prediction of future dangerousness of a newly convicted murderer. To what extent has the judgment of future dangerousness matched actuarial data of subsequent murders and serious crimes? Using a secondary analysis, this investigation attempted to assemble available data of postconviction dangerousness of death sentenced capital murderers to create a more comprehensive actuarial account of subsequent dangerousness and to present the data in a common format used by the Federal Bureau of Investigation and the Bureau of Justice Statistics. Across 14 studies identified with relevant data, there were 13 instances of subsequent murder and 462 serious crime or prison rule violations.  相似文献   
23.
Two habituation experiments were conducted to investigate how 4‐month‐old infants perceive partly occluded shapes. In the first experiment, we presented a simple, partly occluded shape to the infants until habituation was reached. Then we showed either a probable completion (one that would be predicted on the basis of both local and global cues) or an improbable completion. Longer looking times were found for the improbably completed shape (compared to probable and control conditions), suggesting that the probable shape was perceived during partial occlusion. In the second experiment, infants were habituated to more ambiguous partly occluded shapes, where local and global cues would result in different completions. For adults, the percept of these shapes is usually dominated by global influences. However, after habituation the infants looked longer at the globally completed shapes. These results suggest that by the age of 4 months, infants are able to infer the perceptual completion of partly occluded shapes, but for more ambiguous shapes, this completion seems to be dominated by local influences.  相似文献   
24.
Although Latinas/os have a long history in the USA and represent a growing percentage of the population, they remain largely invisible or stereotyped in dominant images and discourses. Such representations are often ahistorical, and they camouflage the effects of US power and inequality. However, the spring 2006 immigrant rights demonstrations disturbed dominant conceptions. The demonstrators called attention to the contradictory US practices that disrupt home countries, recruit labor migrants, and deny immigrants full participation. Likewise, the role of students in these demonstrations spurred reflections on why youth would walk out of their schools for immigrant rights. Inspired by these demonstrations, we combine materials from multiple disciplines to emphasize the significance of US imperialism, exploitation, and exclusion on Latina/o migration, education, and activism. Key to this article is a reframing of how the media, K-12 curriculum, and popular discourse often engage in a cultural cover-up that sustains inequality.  相似文献   
25.
There is an emerging consensus in empirical finance that realized volatility series typically display long range dependence with a memory parameter (d) around 0.4 (Andersen et al., 2001; Martens et al., 2004). The present article provides some illustrative analysis of how long memory may arise from the accumulative process underlying realized volatility. The article also uses results in Lieberman and Phillips (2004, 2005) to refine statistical inference about d by higher order theory. Standard asymptotic theory has an O(n-1/2) error rate for error rejection probabilities, and the theory used here refines the approximation to an error rate of o(n-1/2). The new formula is independent of unknown parameters, is simple to calculate and user-friendly. The method is applied to test whether the reported long memory parameter estimates of Andersen et al. (2001) and Martens et al. (2004) differ significantly from the lower boundary (d = 0.5) of nonstationary long memory, and generally confirms earlier findings.  相似文献   
26.
We examine the effects of the U.S.-Japan trade restraint on automobile prices and quality upgrading, for both Japanese imports and American small cars. From April 1981 to April 1984 the suggested retail price of all Japanese models increased by 15.8 percent, or 5.3 percent per year. We find that nearly the entire amount of this rise can be explained by the upgrading of individual models. This upgrading may benefit consumers who would purchase a luxury import in any case, but harms those who desire the basic imports. In addition to upgrading, we conclude that a second cost of the trade restraint has been to prevent the yen depreciation from being passed onto American consumers, in terms of lower imported auto prices. For U.S. small cars we find a 9.1 percent rise in the suggested retail price, or 3 percent per year, with a fraction of this amount due to model upgrading. If the yen depreciation had led to lower import prices without the trade restraint, then we expect that U.S. auto prices would have been lower, too.  相似文献   
27.
The research reported in this article is based on a study of the strategic planning practices of the 500 fastest growing privately held smaller companies in the United States ranked according to percentage of sales increases from 1978 to 1982.p1 Based on the information provided, a clear picture emerges regarding the actual role of strategic planning in rapid growth companies.  相似文献   
28.
Owing to the extreme quantiles involved, standard control charts are very sensitive to the effects of parameter estimation and non-normality. More general parametric charts have been devised to deal with the latter complication and corrections have been derived to compensate for the estimation step, both under normal and parametric models. The resulting procedures offer a satisfactory solution over a broad range of underlying distributions. However, situations do occur where even such a large model is inadequate and nothing remains but to consider non- parametric charts. In principle, these form ideal solutions, but the problem is that huge sample sizes are required for the estimation step. Otherwise the resulting stochastic error is so large that the chart is very unstable, a disadvantage that seems to outweigh the advantage of avoiding the model error from the parametric case. Here we analyse under what conditions non-parametric charts actually become feasible alternatives for their parametric counterparts. In particular, corrected versions are suggested for which a possible change point is reached at sample sizes that are markedly less huge (but still larger than the customary range). These corrections serve to control the behaviour during in-control (markedly wrong outcomes of the estimates only occur sufficiently rarely). The price for this protection will clearly be some loss of detection power during out-of-control. A change point comes in view as soon as this loss can be made sufficiently small.  相似文献   
29.
Informal caregivers of individuals with Alzheimer's disease spend a considerable amount of time providing care. In this paper, we use Grossman's health production and Becker's time allocation models to develop a model of informal care provision to elderly dementia patients. In our model, time inputs produce caregiving services, which provides utility to the caregiver, but reduces leisure. We assume that time is less productive of services on the margin as the disease progresses. In this framework, an increase in patients' disease severity does not necessarily increase informal caregiver time input. The cost of formal care establishes a reservation price for informal caregiving. When the costs of informal caregiving rise above this reservation level, the patient is institutionalized. We test empirically the effect of deterioration in the patients' condition, proxied by both disease severity and dementia problem behavior, on informal caregiving time. We find that dementia-related problem behaviors and functional limitations significantly increase inputs of informal caregiving time. Patients' problem behavior exerts a modifying effect on functional limitations, and patients' comorbidities have no effect on informal caregiving time.  相似文献   
30.
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