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   7692篇
  免费   336篇
  国内免费   94篇
管理学   434篇
劳动科学   10篇
民族学   139篇
人才学   1篇
人口学   163篇
丛书文集   1474篇
理论方法论   395篇
综合类   4701篇
社会学   308篇
统计学   497篇
  2024年   12篇
  2023年   44篇
  2022年   140篇
  2021年   156篇
  2020年   138篇
  2019年   104篇
  2018年   102篇
  2017年   179篇
  2016年   153篇
  2015年   250篇
  2014年   324篇
  2013年   429篇
  2012年   359篇
  2011年   525篇
  2010年   527篇
  2009年   540篇
  2008年   505篇
  2007年   549篇
  2006年   530篇
  2005年   460篇
  2004年   294篇
  2003年   340篇
  2002年   417篇
  2001年   347篇
  2000年   206篇
  1999年   99篇
  1998年   66篇
  1997年   52篇
  1996年   54篇
  1995年   54篇
  1994年   34篇
  1993年   34篇
  1992年   22篇
  1991年   25篇
  1990年   14篇
  1989年   10篇
  1988年   9篇
  1987年   1篇
  1986年   4篇
  1985年   5篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
  1977年   1篇
  1974年   1篇
  1967年   1篇
排序方式: 共有8122条查询结果,搜索用时 625 毫秒
291.
葛依克勒氏赫哲族是赫哲族中比较单一的古老氏族,居住在乌苏里江口的德新,为黑龙江下游的土著居民.清初,清廷通过采取军事征讨、招抚内迁、编户贡貂赏乌绫、编旗设佐、三姓建置等各项措施,对葛氏赫哲族进行了有效的社会控制,最终形成了独特的军政合一的管理体制.事实证明:上述措施的实行是成功的.它不仅有效地维护了黑龙江、松花江和乌苏里江流域地区地方管理、发展了葛氏赫哲族社会生产,而且加强了民族团结与融合,最终也起到了巩固东北部边疆的重要作用.  相似文献   
292.
高师微型有机化学实验与绿色化学研究与实践   总被引:1,自引:0,他引:1  
有机化学实验的绿色化正逐渐成为当前有机化学实验教学改革的方向.有机化学实验的微型化是实验教学的一项有效的绿色化措施.通过对有机化学实验绿色化和微型化教学改革实践,提出了在高师有机化学实验教学中通过树立绿色化学意识、采用微型化实验、改革教学内容、精心安排化学实验来对学生进行绿色化学教育.  相似文献   
293.
The rural Minimum Living Standard Guarantee (Dibao) Scheme is the most important social assistance programme in rural China. However, how the rural Dibao programme affects household expenditures and whether it can enable the poor to escape the poverty trap are questions that remain largely unexplored. This study used data from the 2012 Rural Household Survey in China to investigate the impact of the rural Dibao programme on household expenditures. We found that the programme significantly improved the well‐being of low‐income households. Particularly, the programme significantly increased household expenditures on housing, education and health; furthermore, the impact was greater for households with educated household heads. However, the programme did not significantly affect household expenditures on food, transportation or farming inputs. The results imply that participation in the rural Dibao programme induces household investment in human capital, which could help to break the inter‐generational transmission of poverty and raise long‐run welfare.  相似文献   
294.
One of the most important policy objectives in the post-apartheid South African economy is to reduce poverty. Although economic growth and job creation are the preferred sources of alleviating poverty and inequality, social grant spending has contributed significantly to reduce poverty (Van der Berg et al. in Poverty trends since the transition: what we know. Stellenbosch Economic Working Papers: 19/09. Stellenbosch: Stellenbosch University, 2009). Recently proposals were tabled by the Department of Social Development of South Africa (Fin24 in R3.3bn plan to extend child support grant to 21. http://www.fin24.com/Economy/R33bn-child-care-grant-extension-to-21-on-cards-20150316. Accessed August 7, 2015, 2015) to extend the age eligibility of the child support grant (CSG) to 21 years (at the time of writing children aged up to 18 years are eligible). This sparked an interest to investigate the impact on poverty of changes to the eligibility criteria of CSG, as well as its fiscal implications. Using person and household data from the 2010/2011 Income and Expenditure Survey, various simulations are performed to assess the impact on poverty rates and changes to social spending, given the following changes: (1) if all age-eligible children applied; (2) if all beneficiaries received the grant amount for the full 12-month duration; (3) if the age eligibility criterion is extended; and (4) if the monthly child grant income amount is revised upwards. We also examine how changes in the eligibility criteria affect the income distribution.  相似文献   
295.
Objective: To analyze the impact of age, BMI and sex hormone on aging males’ symptoms (AMS) and the 5-item version of the international index of erectile function (IIEF-5) scores in middle-aged and elderly Chinese men.

Methods: A population-based cross-sectional study was conducted in Jiashan County. A total of 969 men, aged between 40 and 80 years old, were admitted. Physical examination and the sex hormones were measured, and AMS and IIEF-5 scores were assessed.

Results: The oneway ANOVA analysis indicated older age groups had higher AMS total-scores, somatic and sexual sub-scores, and lower IIEF5 scores (all p?rpairwise) analyses showed the significant associations between AMS and age or sex hormone (cFT, Bio-T, SHBG, and LH) levels, and similar for IIEF5. However, when age was adjusted, the correlation coefficients (rpartial) weakened, and correlation significance disappeared, except LH (for AMS: rpartial?=?0.096, p?=?.009; for IIEF-5: rpartial?= ?0.140, p?=?.001). Multiple linear regressions confirmed the influence of increased age and LH on the AMS and IIEF5 scores.

Conclusion: CFT, Bio-T and SHBG failed to yield any additional predicting information when age was adjusted. To improve the male reproductive health, future research should pay more attention on aging-related comorbidities and how to improve general wellness.  相似文献   
296.
In multiple hypothesis test, an important problem is estimating the proportion of true null hypotheses. Existing methods are mainly based on the p-values of the single tests. In this paper, we propose two new estimations for this proportion. One is a natural extension of the commonly used methods based on p-values and the other is based on a mixed distribution. Simulations show that the first method is comparable with existing methods and performs better under some cases. And the method based on a mixed distribution can get accurate estimators even if the variance of data is large or the difference between the null hypothesis and alternative hypothesis is very small.  相似文献   
297.
We study objective Bayesian inference for linear regression models with residual errors distributed according to the class of two-piece scale mixtures of normal distributions. These models allow for capturing departures from the usual assumption of normality of the errors in terms of heavy tails, asymmetry, and certain types of heteroscedasticity. We propose a general non-informative, scale-invariant, prior structure and provide sufficient conditions for the propriety of the posterior distribution of the model parameters, which cover cases when the response variables are censored. These results allow us to apply the proposed models in the context of survival analysis. This paper represents an extension to the Bayesian framework of the models proposed in [16]. We present a simulation study that shows good frequentist properties of the posterior credible intervals as well as point estimators associated to the proposed priors. We illustrate the performance of these models with real data in the context of survival analysis of cancer patients.  相似文献   
298.
This paper investigates tail behavior of the randomly weighted sum ∑nk = 1θkXk and reaches an asymptotic formula, where Xk, 1 ? k ? n, are real-valued linearly wide quadrant-dependent (LWQD) random variables with a common heavy-tailed distribution, and θk, 1 ? k ? n, independent of Xk, 1 ? k ? n, are n non-negative random variables without any dependence assumptions. The LWQD structure includes the linearly negative quadrant-dependent structure, the negatively associated structure, and hence the independence structure. On the other hand, it also includes some positively dependent random variables and some other random variables. The obtained result coincides with the existing ones.  相似文献   
299.
The aim of this paper is to propose methods of detecting change in the coefficients of a multinomial logistic regression model for categorical time series offline. The alternatives to the null hypothesis of stationarity can be either the hypothesis that it is not true, or that there is a temporary change in the sequence. We use the efficient score vector of the partial likelihood function. This has several advantages. First, the alternative value of the parameter does not have to be estimated; hence, we have a procedure that has a simple structure with only one parameter estimation using all available observations. This is in contrast with the generalized likelihood ratio-based change point tests. The efficient score vector is used in various ways. As a vector, its components correspond to the different components of the multinomial logistic regression model’s parameter vector. Using its quadratic form a test can be defined, where the presence of a change in any or all parameters is tested for. If there are too many parameters one can test for any subset while treating the rest as nuisance parameters. Our motivating example is a DNA sequence of four categories, and our test result shows that in the published data the distribution of the four categories is not stationary.  相似文献   
300.
As an effective tool for data storage, processing, and computing, ontology has been used in many fields of computer science and information technology. By means of its powerful performance on semantic query and knowledge extraction, domain ontology has been built on various disciplines such as biology, pharmaceutics, geography, chemistry, etc. and been smoothly employed for their engineering applications. In these ontology applications, we aim to get an optimal ontology function which maps each ontology to a real number and then determine the similarity between concepts by the distance of their corresponding real numbers. In former ontology learning approaches, all the instances in the training sample have equal status in the learning process. In this article, we present the disequilibrium multi-dividing ontology algorithm in which the important ontology data will be highlighted during the learning, and the relevant ontology data tend to be eliminated. Four experiments are designed to test the serviceability of our disequilibrium multi-dividing algorithm from angles of ontology similarity measuring and ontology mapping construction.  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