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   898篇
  免费   13篇
教育   696篇
科学研究   73篇
各国文化   12篇
体育   71篇
文化理论   10篇
信息传播   49篇
  2021年   6篇
  2020年   28篇
  2019年   40篇
  2018年   23篇
  2017年   27篇
  2016年   33篇
  2015年   25篇
  2014年   26篇
  2013年   210篇
  2012年   19篇
  2011年   14篇
  2010年   11篇
  2009年   17篇
  2008年   14篇
  2007年   15篇
  2006年   20篇
  2005年   18篇
  2004年   24篇
  2003年   13篇
  2002年   19篇
  2001年   16篇
  2000年   17篇
  1999年   5篇
  1998年   7篇
  1997年   8篇
  1996年   9篇
  1995年   15篇
  1994年   6篇
  1993年   7篇
  1992年   8篇
  1991年   7篇
  1990年   11篇
  1989年   7篇
  1988年   7篇
  1987年   6篇
  1986年   8篇
  1985年   8篇
  1984年   5篇
  1982年   6篇
  1981年   7篇
  1979年   7篇
  1976年   8篇
  1973年   6篇
  1972年   11篇
  1970年   7篇
  1969年   7篇
  1968年   6篇
  1921年   7篇
  1920年   6篇
  1918年   5篇
排序方式: 共有911条查询结果,搜索用时 31 毫秒
91.
Paul Evan Peters begins his discussion of library standards with a convincing argument that the acceptance by librarians of the need for order and standards is not a character flaw. Rather, in promoting the use of standards, librarians are efficiently forwarding their missions to build and organize collections and to make them accessible to their clients. Pointing out the economic realities of contemporary libraries, Peters further argues that standards are appealing because they help librarians to control costs. Paul Evan Peters, systems coordinator for the New York Public Library, is vice chairperson of the National Information Standards Organization and principal representative of the American Library Association to Accredited Standards Committee X3 (Information Processing Systems). Address for correspondence.  相似文献   
92.
93.
94.
95.
96.
97.
The present work describes the operation and simulation of a microfluidic laminar-flow mixer. Diffusive mixing takes place between a core solution containing lipids in ethanol and a sheath solution containing aqueous buffer, leading to self assembly of liposomes. Present device architecture hydrodynamically focuses the lipid solution into a cylindrical core positioned at the center of a microfluidic channel of 125 × 125-μm2 cross-section. Use of the device produces liposomes in the size range of 100–300 nm, with larger liposomes forming at greater ionic strength in the sheath solution and at lower lipid concentration in the core solution. Finite element simulations compute the concentration distributions of solutes at axial distances of greater than 100 channel widths. These simulations reduce computation time and enable computation at long axial distances by utilizing long hexahedral elements in the axial flow region and fine tetrahedral elements in the hydrodynamic focusing region. Present meshing technique is generally useful for simulation of long microfluidic channels and is fully implementable using comsol Multiphysics. Confocal microscopy provides experimental validation of the simulations using fluorescent solutions containing fluorescein or enhanced green fluorescent protein.  相似文献   
98.
Abstract This study examined dissonance in physical activity (PA) between two youth-specific hip-derived intensity cut-points for the Actiwatch (AW), and compared PA between hip and wrist placements using site-specific cut-points. Twenty-four children aged 11.2?±?0.5 years wore the AW on the right hip and non-dominant wrist during a typical school day. Minutes of sedentary behaviour and vigorous activity were greater using Puyau et al. (2002) cut-points, but light, moderate, and moderate-to-vigorous (MVPA) were greater when derived using Puyau et al. (2004) cut-points (P?相似文献   
99.
OBJECTIVE: The current study examined the prevalence and characteristics of childhood sexual abuse in a jailed-based population. METHODOLOGY: A retrospective, self-reported survey was administered over an 8-week period to a random sample of 100 men who were incarcerated in a county jail in Southeastern Texas. The survey included questions about childhood sexual experiences before and after puberty, drug history and use, and sexual risk-taking behaviors. RESULTS: Of the 100 male inmates who participated in this study, 59% reported experiencing some form of sexual abuse before puberty, and all such instances occurred before or at the age of 13 years. The first episode of childhood sexual abuse began at an average age of 9.6 years (SD = 2.4), and ended at an average age of 13.0 years (SD = 2.3). Kissing and touching without intercourse (64%) was the common pattern of sexual abuse experience reported. The total number of perpetrators was 165, with 10% male and 90% female. Friends (n = 72) and family (n = 56) were the most frequent perpetrators. CONCLUSION: Childhood sexual abuse may be more prevalent among inmates than among males in the general population. These results show a high percentage of inmates who report a history of childhood sexual abuse; this rate is higher than those reported by other studies for incarcerated males. The findings support the belief held by professionals in the criminal justice field that a significant number of incarcerated males may have been victims of sexual abuse.  相似文献   
100.
Abstract

Purpose: The objective of this article is to analyze the introduction of participatory extension approaches (PEA) in the predominantly supply-driven, hierarchical Vietnamese extension system. Drawing on the case of the so-called Farmer Livestock School (FLS) concept, the authors investigate the potential and challenges of scaling up and out the FLS/PEA principles of participatory training methods, encompassing intensive and interactive training sessions, group-based sharing of experience, practical learning, and learning-by-doing processes.

Design/Methodology/Approach: The article is based on data collected and synthesized from 36 pilot communes from 2000 to 2007 and draws on the extensive insider experience of two of its authors during their work for a DANIDA-funded livestock project.

Findings: At the micro-scale and with external support, FLS has been a successful experiment of using participatory extension approaches in farmer training and extension in the livestock sector. Yet, possibilities of scaling up and institutionalizing FLS remain a challenge given the capacity and resource limitations and the resistance at various levels within the Vietnamese extension system.

Practical Implications: The starting point for successfully institutionalizing participatory extension approaches should be to assess the existing system's root problems and capacities and then gradually and systematically introduce institutional innovations rather than aiming at a complete overhaul of a system that may result in the creation of a parallel universe.

Originality/Value: The FLS project provided a unique opportunity to study the enabling and constraining factors of institutionalizing participatory extension approaches in a traditionally top-down oriented extension system beyond the immediate duration of an externally orchestrated project.  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