全文获取类型
收费全文 | 91582篇 |
免费 | 2793篇 |
国内免费 | 3篇 |
专业分类
管理学 | 12398篇 |
民族学 | 563篇 |
人才学 | 25篇 |
人口学 | 7225篇 |
丛书文集 | 527篇 |
教育普及 | 2篇 |
理论方法论 | 9426篇 |
现状及发展 | 1篇 |
综合类 | 2189篇 |
社会学 | 43109篇 |
统计学 | 18913篇 |
出版年
2023年 | 504篇 |
2021年 | 568篇 |
2020年 | 1511篇 |
2019年 | 2218篇 |
2018年 | 2140篇 |
2017年 | 3191篇 |
2016年 | 2417篇 |
2015年 | 2038篇 |
2014年 | 2629篇 |
2013年 | 18843篇 |
2012年 | 2481篇 |
2011年 | 2258篇 |
2010年 | 2021篇 |
2009年 | 2223篇 |
2008年 | 2124篇 |
2007年 | 1929篇 |
2006年 | 2129篇 |
2005年 | 2326篇 |
2004年 | 2207篇 |
2003年 | 1920篇 |
2002年 | 2019篇 |
2001年 | 2043篇 |
2000年 | 1804篇 |
1999年 | 1707篇 |
1998年 | 1510篇 |
1997年 | 1363篇 |
1996年 | 1316篇 |
1995年 | 1342篇 |
1994年 | 1323篇 |
1993年 | 1296篇 |
1992年 | 1314篇 |
1991年 | 1234篇 |
1990年 | 1204篇 |
1989年 | 1040篇 |
1988年 | 1134篇 |
1987年 | 1011篇 |
1986年 | 917篇 |
1985年 | 1081篇 |
1984年 | 1136篇 |
1983年 | 1020篇 |
1982年 | 945篇 |
1981年 | 865篇 |
1980年 | 822篇 |
1979年 | 872篇 |
1978年 | 780篇 |
1977年 | 717篇 |
1976年 | 661篇 |
1975年 | 644篇 |
1974年 | 518篇 |
1973年 | 442篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
261.
Zhu Carolyn W. Moore Michael J. Clipp Elizabeth C. 《Review of Economics of the Household》2003,1(1-2):59-76
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
262.
Diagnostics for dependence within time series extremes 总被引:1,自引:0,他引:1
Anthony W. Ledford Jonathan A. Tawn 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2003,65(2):521-543
Summary. The analysis of extreme values within a stationary time series entails various assumptions concerning its long- and short-range dependence. We present a range of new diagnostic tools for assessing whether these assumptions are appropriate and for identifying structure within extreme events. These tools are based on tail characteristics of joint survivor functions but can be implemented by using existing estimation methods for extremes of univariate independent and identically distributed variables. Our diagnostic aids are illustrated through theoretical examples, simulation studies and by application to rainfall and exchange rate data. On the basis of these diagnostics we can explain characteristics that are found in the observed extreme events of these series and also gain insight into the properties of events that are more extreme than those observed. 相似文献
263.
The Coase theorem maintains that where free-market precepts exist, the allocation of property rights does not impact the distribution of resources. An application to Major League Baseball suggests that institutions such as free agency and the reverse-order amateur draft would not impact player distributions and therefore would not impact competitive balance. The present study finds that the distribution of wins is generally consistent with the precepts of the Coase theorem and therefore suggests a course for those who wish to alter the level of competitive balance: Major League Baseball should increase its focus on expanding the size of its labor pool. (JEL O15 , L83 , C22 ) 相似文献
264.
文章剖析了英美物权法上“使用权”的概念 ,并解释了财产权就像“权利集束”这个常用比喻 ,并对美国普通法上财产法中的有关相邻方之间土地纠纷的法规进行了比较分析 ,其中特别比较了普通法上的私人妨害原则和中国物权法草案第 9章所规定的相邻权的概念 ,并将普通法体系中的各种私人土地使用协议和地役权与中国物权法草案第 16章的内容进行了对比。 相似文献
265.
Expectations, Capital Gains, and Income 总被引:2,自引:0,他引:2
A theoretical framework for the measurement of income under uncertainty is developed that addresses some long-standing controversies about the treatment of capital gains. The consequences for economic analysis and policy making are potentially serious, because the treatment of capital gains can significantly affect some major macroeconomic aggregates, including national income and savings, balance of payments deficits, government deficits, and depreciation. (JEL O47 , P44 , Q32 ) 相似文献
266.
目的 :回顾气囊扩张治疗贲门失弛缓症的近、远期疗效及治疗过程中的经验。方法 :对经食管吞钡X线拍片确诊的 16例贲门失弛缓症患者 ,采用内镜下气囊扩张治疗并评价其近、远期疗效。结果 :近期疗效 :16例患者中 ,12例 (75 % )显效 ,4例 (2 5 % )有效 ,总有效率为 10 0 % ;远期疗效 :16例患者中 ,1例 2周后复发经再次扩张治疗后未复发 ,另有 1例在治疗后的半年内复发扩张治疗后 ,半年再次复发 ,经直径 4 .0cm气囊扩张后 4年未复发。结论 :气囊扩张治疗贲门失弛缓症有效、易操作、安全、并发症少及复发率低 ,但有较多的细小经验及体会值得总结 ,以便更完善和更成熟。 相似文献
267.
Edward E. Potter 《Journal of Labor Research》2003,24(1):73-84
Conclusion Throughout American history, first on the family farm and now in modern day business institutions, the workplace has been
a stabilizing institution in American society that has anchored the ongoing, informal interactions occurring outside the workplace.
In 1900, few Americans had a private mode of transportation. Barely 4,000 passenger automobiles were sold in 1900, and while
horses were common, they were used primarily for farming, public transportation, and commercial activity in cities. By 1930,
nearly 40 million cars had been added to America’s streets. The automobile recast life and work in central cities and eventually
the suburbs. 相似文献
268.
Craig H. Mallinckrodt John G. Watkin Geert Molenberghs Raymond J. Carroll 《Pharmaceutical statistics》2004,3(3):161-169
Missing data, and the bias they can cause, are an almost ever‐present concern in clinical trials. The last observation carried forward (LOCF) approach has been frequently utilized to handle missing data in clinical trials, and is often specified in conjunction with analysis of variance (LOCF ANOVA) for the primary analysis. Considerable advances in statistical methodology, and in our ability to implement these methods, have been made in recent years. Likelihood‐based, mixed‐effects model approaches implemented under the missing at random (MAR) framework are now easy to implement, and are commonly used to analyse clinical trial data. Furthermore, such approaches are more robust to the biases from missing data, and provide better control of Type I and Type II errors than LOCF ANOVA. Empirical research and analytic proof have demonstrated that the behaviour of LOCF is uncertain, and in many situations it has not been conservative. Using LOCF as a composite measure of safety, tolerability and efficacy can lead to erroneous conclusions regarding the effectiveness of a drug. This approach also violates the fundamental basis of statistics as it involves testing an outcome that is not a physical parameter of the population, but rather a quantity that can be influenced by investigator behaviour, trial design, etc. Practice should shift away from using LOCF ANOVA as the primary analysis and focus on likelihood‐based, mixed‐effects model approaches developed under the MAR framework, with missing not at random methods used to assess robustness of the primary analysis. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
269.
Bias Correction in the Dynamic Panel Data Model with a Nonscalar Disturbance Covariance Matrix 总被引:1,自引:0,他引:1
Maurice J. G. Bun 《Econometric Reviews》2003,22(1):29-58
Approximation formulae are developed for the bias of ordinary and generalized Least Squares Dummy Variable (LSDV) estimators in dynamic panel data models. Results from Kiviet [Kiviet, J. F. (1995), on bias, inconsistency, and efficiency of various estimators in dynamic panel data models, J. Econometrics68:53-78; Kiviet, J. F. (1999), Expectations of expansions for estimators in a dynamic panel data model: some results for weakly exogenous regressors, In: Hsiao, C., Lahiri, K., Lee, L-F., Pesaran, M. H., eds., Analysis of Panels and Limited Dependent Variables, Cambridge: Cambridge University Press, pp. 199-225] are extended to higher-order dynamic panel data models with general covariance structure. The focus is on estimation of both short- and long-run coefficients. The results show that proper modelling of the disturbance covariance structure is indispensable. The bias approximations are used to construct bias corrected estimators which are then applied to quarterly data from 14 European Union countries. Money demand functions for M1, M2 and M3 are estimated for the EU area as a whole for the period 1991: I-1995: IV. Significant spillovers between countries are found reflecting the dependence of domestic money demand on foreign developments. The empirical results show that in general plausible long-run effects are obtained by the bias corrected estimators. Moreover, finite sample bias, although of moderate magnitude, is present underlining the importance of more refined estimation techniques. Also the efficiency gains by exploiting the heteroscedasticity and cross-correlation patterns between countries are sometimes considerable. 相似文献
270.