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   1934篇
  免费   57篇
管理学   293篇
民族学   15篇
人口学   207篇
丛书文集   20篇
理论方法论   151篇
综合类   135篇
社会学   882篇
统计学   288篇
  2023年   25篇
  2022年   17篇
  2021年   23篇
  2020年   68篇
  2019年   71篇
  2018年   94篇
  2017年   124篇
  2016年   93篇
  2015年   53篇
  2014年   77篇
  2013年   233篇
  2012年   249篇
  2011年   71篇
  2010年   56篇
  2009年   51篇
  2008年   43篇
  2007年   53篇
  2006年   38篇
  2005年   44篇
  2004年   94篇
  2003年   91篇
  2002年   69篇
  2001年   48篇
  2000年   30篇
  1999年   10篇
  1998年   7篇
  1997年   5篇
  1996年   11篇
  1995年   8篇
  1994年   7篇
  1993年   6篇
  1992年   13篇
  1991年   9篇
  1990年   9篇
  1989年   8篇
  1988年   5篇
  1987年   9篇
  1985年   4篇
  1984年   5篇
  1983年   5篇
  1982年   6篇
  1981年   7篇
  1980年   6篇
  1979年   3篇
  1978年   5篇
  1975年   3篇
  1974年   4篇
  1968年   2篇
  1967年   3篇
  1966年   2篇
排序方式: 共有1991条查询结果,搜索用时 0 毫秒
61.
The urban domestic gardens that are part of urban green areas have become a very important element due to their ecosystematic benefits and the poor information about them. Information regarding the floristic richness of three socioeconomic stratifications from the city of Heredia, Costa Rica is presented in this study. Research was conducted from October 2011 to May 2012. Information was collected using a semi-structured questionnaire, which was provided to 61 garden owners, including the owner’s personal data, time living in the dwelling, area of the property and the garden, variation of its size in time and the garden’s location on the property. In addition, a floristic inventory was conducted in each garden as well as a taxonomic identification of all plants. Vegetative forms and substrates were also noted. Characteristics of the gardens and their owners were then analyzed to determine the relationship of species richness between the three sites studied. The number of plant species recorded was 618, corresponding to 102 families (19 % exotic). Regarding geographical origin, 64, 4 % were exotic, 35,6 % native. Orchidaceae (93 spp.) and Araceae (39 spp.) were the most dominant families. The variables of garden area and location and owner's age determined the garden’s floristic richness. In addition, the garden’s area and vegetative forms varied among the sites studied probably due to socioeconomic differences among them. Diversity of pioneer plants increased with the garden’s area. In sum, this research provides important floristic information of domestic gardens, since, being private property, data about them is scarce and municipal management guidelines are nonexistent.  相似文献   
62.
In a recent article from the Annals of Applied Statistics, Cox discussed the main phases of applied statistical research ranging from clarifying study objectives to final data analysis and interpreting results. As an incidental remark to these main phases, we advocate that beyond cleaning and preprocessing the data, it is a good practice to audit the data to determine if they can be trusted at all. A case study based on Ghanaian Official Fishery Statistics is used to illustrate this need, with Benford's law being the tool used to carrying out the data audit. Supplementary materials for this article are available online.  相似文献   
63.
High-content automated imaging platforms allow the multiplexing of several targets simultaneously to generate multi-parametric single-cell data sets over extended periods of time. Typically, standard simple measures such as mean value of all cells at every time point are calculated to summarize the temporal process, resulting in loss of time dynamics of the single cells. Multiple experiments are performed but observation time points are not necessarily identical, leading to difficulties when integrating summary measures from different experiments. We used functional data analysis to analyze continuous curve data, where the temporal process of a response variable for each single cell can be described using a smooth curve. This allows analyses to be performed on continuous functions, rather than on original discrete data points. Functional regression models were applied to determine common temporal characteristics of a set of single cell curves and random effects were employed in the models to explain variation between experiments. The aim of the multiplexing approach is to simultaneously analyze the effect of a large number of compounds in comparison to control to discriminate between their mode of action. Functional principal component analysis based on T-statistic curves for pairwise comparison to control was used to study time-dependent compound effects.  相似文献   
64.
In this paper, we propose a new bivariate distribution, namely bivariate alpha-skew-normal distribution. The proposed distribution is very flexible and capable of generalizing the univariate alpha-skew-normal distribution as its marginal component distributions; it features a probability density function with up to two modes and has the bivariate normal distribution as a special case. The joint moment generating function as well as the main moments are provided. Inference is based on a usual maximum-likelihood estimation approach. The asymptotic properties of the maximum-likelihood estimates are verified in light of a simulation study. The usefulness of the new model is illustrated in a real benchmark data.  相似文献   
65.
Based on a sample of older workers from the Maastricht Cohort Study, the authors investigate the prevalence and dynamics of self‐reported under‐skilling and its effects on workers' need for recovery, their risk of losing employment and their retirement intentions over a two‐year period. They find that being under‐skilled is associated both with higher levels of need for recovery over time and with the risk of losing employment, but not with early retirement intentions. To achieve sustainable employment, they argue, the course of under‐skilling should be monitored throughout workers' careers, enabling timely interventions to avoid its negative consequences.  相似文献   
66.
This paper describes the population of children in care in New South Wales, Australia, who were adopted by their foster families (N?=?372) from 2003 to 2014. Data pertaining to 370 of these adoptees were available and obtained from administrative records accompanying adoption applications. Most of these children had been placed with their subsequent adoptive family during infancy. However, adoption orders occurred much later in their lives. According to the available information at the time of adoption, these children did not suffer the high levels of mental health problems typically identified in populations of children in foster care. Though the data do not include follow-up to determine if the contact agreed upon at the time of adoption orders translated into practice, the most frequently postadoption arrangement recorded was face-to-face contact, four times a year with mother and siblings. The high levels of openness and face-to-face contact in Australian adoptions from care are a significant point of difference with other adoption models, and presents a need for research in the area.

IMPLICATIONS
  • Following the change of legislation in New South Wales, Australia, that prioritises open adoption over foster care, social workers in the field of child protection are well placed to assist in this process.

  • Social workers can assess children entering care to identify those who will benefit from adoption in a timely manner; undertake casework and administrative aspects of the adoption process; work closely with the child, and birth and adoptive families by delivering pre- and post-adoption supports; and conduct longitudinal research on the outcomes for children adopted from care.

  相似文献   
67.
Theory and Society - This article presents fashion as a mechanism of domination and political legitimacy, focusing on Soviet-type state socialist regimes. In particular, it documents some dynamics...  相似文献   
68.
The way public policies are managed in Brazil has changed since the 1988 Federal Constitution. This study aimed to identify how changes in the structure of public expenditure composition at Brazilian federal states influenced local human development in these states. The states’ public expenditures were categorized according to their nature as spending indices whereas human development was measured through a human development index (HD). To verify the relationships between these variables, an accounting-social theoretical model was created and estimated through latent growth modeling (LGM). The LGM measurement period comprised five administration cycles of the Brazilian states (1988–2011). Variables were measured on data of the second year of state government term; their mean initial values and growth rates were recorded. Results show that, influenced by policies of centralized regulation promoted by the federal government, only the social spending growth rates had statistically significant effect on the human development growth rate, although not considered of great magnitude. Among mean initial values, the most significant was that of minimum spending (SIm), which denotes the direct impact of the Fiscal Accountability Law [Lei de Responsabilidade Fiscal, in Portuguese] on human development improvements. The mean initial value of economic spending also showed a positive and significant effect on HD growth rate.  相似文献   
69.
Introduction: Metabolic syndrome (MetS) is a constellation of interrelated risk factors of metabolic origin. Some studies suggest a possible link between low total testosterone (TT) levels and the presence of MetS.

Aim: To analyze the strength and independence of associations between TT and MetS components in non-diabetic men.

Methods: In this cross-sectional study, 143 non-diabetic men older than 40 were analyzed.

Main outcomes measure: Blood samples were collected to evaluate metabolic profile and TT levels. MetS was defined as the presence of three or more of the following characteristics: fasting blood glucose levels?≥?100?mg/dL, triglyceride?≥?150?mg/dL, HDL-c??102?cm.

Results: Mean age of the study population was 61.5?±?8.61 years old. MetS was present in 47.9% of the individuals. Thirty-four men had low TT and MetS was observed in 23 (70%) against 50 (46%) in those with normal TT (≥?300?ng/dL) (OR 4.94, p?p?=?0.03) and HDL-c (Beta: 0.19; p?=?0.04) remained significantly correlated with TT levels.

Conclusions: Low TT levels were associated with MetS diagnosis. Abdominal obesity was the MetS component independently correlated to low TT levels.  相似文献   
70.
The Organic Law on the Improvement of the National Education Quality (Ley Orgánica de Reforma de la Calidad Educativa) readdressed one of the most significant educational issues: educational policies related to immigrant students. Therefore, this is an appropriate moment to evaluate these types of policies in three singular Spanish regions: Madrid, Catalonia and Andalusia. This article presents an analysis of the measures taken in three Spanish regions: Madrid, Catalonia and Andalusia in response to students’ reception, acceptance and enrolment of immigrant students. A qualitative methodology based on the comparative method is used. Diverse similarities, but also specific characteristics and differences, can be found among the three models associated with each region. There are several significant differences that can be appreciated, such as the institutional role, as well as other specific measures. However, singular features are also identified, such as the diverse policies for the use of the vehicular language in each of the cases. Finally, the comparisons highlight various critical aspects, such as attention devoted to the students’ native language and progress towards intercultural education in school strategies and planning.  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