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   1705篇
  免费   61篇
  国内免费   16篇
管理学   125篇
民族学   25篇
人口学   53篇
丛书文集   173篇
理论方法论   102篇
综合类   904篇
社会学   177篇
统计学   223篇
  2024年   3篇
  2023年   14篇
  2022年   34篇
  2021年   53篇
  2020年   43篇
  2019年   46篇
  2018年   42篇
  2017年   78篇
  2016年   52篇
  2015年   59篇
  2014年   130篇
  2013年   208篇
  2012年   121篇
  2011年   120篇
  2010年   123篇
  2009年   109篇
  2008年   152篇
  2007年   98篇
  2006年   83篇
  2005年   58篇
  2004年   32篇
  2003年   29篇
  2002年   20篇
  2001年   27篇
  2000年   6篇
  1999年   7篇
  1998年   4篇
  1997年   2篇
  1996年   1篇
  1995年   2篇
  1994年   3篇
  1993年   2篇
  1992年   4篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1986年   3篇
  1985年   3篇
  1983年   1篇
  1981年   2篇
  1977年   1篇
  1976年   1篇
  1973年   1篇
  1967年   1篇
排序方式: 共有1782条查询结果,搜索用时 15 毫秒
111.
A universal labeling of a graph G is a labeling of the edge set in G such that in every orientation \(\ell \) of G for every two adjacent vertices v and u, the sum of incoming edges of v and u in the oriented graph are different from each other. The universal labeling number of a graph G is the minimum number k such that G has universal labeling from \(\{1,2,\ldots , k\}\) denoted it by \(\overrightarrow{\chi _{u}}(G) \). We have \(2\Delta (G)-2 \le \overrightarrow{\chi _{u}} (G)\le 2^{\Delta (G)}\), where \(\Delta (G)\) denotes the maximum degree of G. In this work, we offer a provocative question that is: “Is there any polynomial function f such that for every graph G, \(\overrightarrow{\chi _{u}} (G)\le f(\Delta (G))\)?”. Towards this question, we introduce some lower and upper bounds on their parameter of interest. Also, we prove that for every tree T, \(\overrightarrow{\chi _{u}}(T)={\mathcal {O}}(\Delta ^3) \). Next, we show that for a given 3-regular graph G, the universal labeling number of G is 4 if and only if G belongs to Class 1. Therefore, for a given 3-regular graph G, it is an \( {{\mathbf {N}}}{{\mathbf {P}}} \)-complete to determine whether the universal labeling number of G is 4. Finally, using probabilistic methods, we almost confirm a weaker version of the problem.  相似文献   
112.
Objectives: To investigate the predictive values of free prostate-specific antigen (fPSA), total PSA (tPSA) and age on the prostate volume.

Methods: The data of 2148 patients with lower urinary tract symptoms were analyzed retrospectively. The patients who had transrectal ultrasonography guided 10 core biopsies owing to the findings obtained on digital rectal examination and presence of high PSA levels (PSA?=?2.5–10?ng/dl), and proven to have BPH histopathologically were included in the study. Age, tPSA, fPSA and the prostate volumes (PV) of the patients were noted.

Results: One thousand patients that fulfilled the inclusion criteria were included in the study. The PV of the patients were significantly correlated with age, tPSA and fPSA (p?r?=?0.307, p?r?=?0.382, p?r?=?0.296, respectively). On linear regression model, fPSA was found as a stronger predictive for PV (AUC?=?0.75, p?p?p?=?0.013).

Conclusions: Although tPSA is an important prognostic factor for predicting PV, the predictive value of fPSA is higher. PV can easily be predicted by using age, and serum tPSA and fPSA levels.  相似文献   
113.
The premise of this paper is that effective supervision and proper internal control system (ICS) can promote accountability and transparency, and this will attract more donors. However, in a developing country like Malaysia, it is common that proper accounting standards are not available, the laws are not enforced, and charities often struggle for survival. Debates on regulating nonprofit organizations (NPOs) have been sensitive to many and are often left unresolved, and some quarters believe that NPOs should be left to handle their own affairs. This paper provides evidence from a survey of 60 charities on the status of their ICS. It briefly describes the current state of regulations in Malaysia and makes a case for better monitoring of the sector, as this might be the reason NPOs are lacking in their ICS. We propose what type of regulation and assistance can be provided by the authorities to this sector, not only in Malaysia but also in other developing countries facing similar challenges.  相似文献   
114.
This article investigates the premise that it is possible to transpose organizational approaches to equal employment opportunity (EEO) from western countries to Muslim majority countries (MMCs). Drawing on policy interviews and documentary evidence from public sector organizations and international development agencies engaged in the promotion of gender equality in Turkey and Pakistan, we question the effectiveness of diffusion of gender equality policies and practices to and among these two MMCs. Our investigation reveals the primacy of context over essence in developing effective ways to construct EEO policies and practices which can be adopted in MMCs.  相似文献   
115.
我国近年来出现了"用工荒"和大学生"就业难"并存的问题,该问题的解决需要从劳动力的"质"上去突破,要通过职业技术培训来改善我国的人才结构。但是我国目前的"学校-企业-培训机构"三位一体的职业技术培训体系还存在诸多不足,文章将从主体资格、培养方式两个方面提出解决对策。  相似文献   
116.
吕娜 《学术探索》2012,(7):53-56
东南亚国家与中国山水相连,文化习俗相近,双方商业合作和友好往来历史悠久,随着中国与东盟经济的快速发展以及自贸区的启动,双方合作空间进一步拓展,发展前景将更加广阔。投资合作是中国—东盟经贸合作的强大推动力,这得益于中国—东盟自由贸易区《投资协议》开始实施,双方开放投资市场,改善投资环境,降低贸易壁垒,为双方企业创造更多投资机会。  相似文献   
117.
Independence of error terms in a linear regression model, often not established. So a linear regression model with correlated error terms appears in many applications. According to the earlier studies, this kind of error terms, basically can affect the robustness of the linear regression model analysis. It is also shown that the robustness of the parameters estimators of a linear regression model can stay using the M-estimator. But considering that, it acquires this feature as the result of establishment of its efficiency. Whereas, it has been shown that the minimum Matusita distance estimators, has both features robustness and efficiency at the same time. On the other hand, because the Cochrane and Orcutt adjusted least squares estimators are not affected by the dependence of the error terms, so they are efficient estimators. Here we are using of a non-parametric kernel density estimation method, to give a new method of obtaining the minimum Matusita distance estimators for the linear regression model with correlated error terms in the presence of outliers. Also, simulation and real data study both are done for the introduced estimation method. In each case, the proposed method represents lower biases and mean squared errors than the other two methods.KEYWORDS: Robust estimation method, minimum Matusita distance estimation method, non-parametric kernel density estimation method, correlated error terms, outliers  相似文献   
118.
In this paper we study the asymptotic behavior of the Bickel–Rosenblatt test in infinite-order autoregressive models. Under some mild conditions, the test statistic based on residuals is shown to have the same limiting distribution as that based on true iid errors. It is also proved that this result remains the same when the nuisance parameters in the model are to be estimated, which means that the Bickel–Rosenblatt test is easily applicable in composite hypothesis goodness-of-fit testing unlike the Kolmogorov–Smirnov type tests. The result of a simulation study is supplemented to verify the result of this paper.  相似文献   
119.
In this paper we consider the problem of determining the optimum number of repairable and replaceable components to maximize a system's reliability when both, the cost of repairing the components and the cost of replacement of components by new ones, are random. We formulate it as a problem of non-linear stochastic programming. The solution is obtained through Chance Constrained programming. We also consider the problem of finding the optimal maintenance cost for a given reliability requirement of the system. The solution is then obtained by using Modified E-model. A numerical example is solved for both the formulations.  相似文献   
120.
《伊芙琳》是詹姆斯·乔伊斯的一篇短篇小说,它短小精悍,却高度浓缩了多重深刻的主题思想。本文拟将通过对这篇短篇小说中的一小段文字进行语篇连贯分析来揭示着深刻的主题思想。  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