全文获取类型
收费全文 | 272篇 |
免费 | 1篇 |
国内免费 | 34篇 |
专业分类
教育 | 133篇 |
科学研究 | 108篇 |
体育 | 9篇 |
综合类 | 12篇 |
信息传播 | 45篇 |
出版年
2022年 | 5篇 |
2021年 | 2篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 11篇 |
2014年 | 16篇 |
2013年 | 21篇 |
2012年 | 23篇 |
2011年 | 40篇 |
2010年 | 20篇 |
2009年 | 19篇 |
2008年 | 13篇 |
2007年 | 25篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 10篇 |
2003年 | 8篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有307条查询结果,搜索用时 0 毫秒
51.
基于皖江城市带产业集群的具体情况,对钻石模型进行修正。随后从资源要素、需求条件、相关与支持性产业、集群的战略结构与竞争、政府作用、机遇、区域文化与外来投资八个方面分析了皖江城市带产业集群的发展,从而提出一些对集群发展有利的对策与建议。 相似文献
52.
综合分析影响房地产市场供给和需求的若干因素,并选取评价区域房地产市场的指标体系,运用系统聚类法分析法对区域房地产市场进行划分,并以安徽省为研究对象,对安徽省16个地市房地产市场划分区域,将安徽省房地产市场划分为A、B、C、D、E、F六个区域,从而为安徽省房地产市场发展提供参考。 相似文献
53.
为充分利用港口既有的建设规模、提高经济效益,对集装箱码头的泊位分配进行研究.采用神经网络和聚类分析两种数据挖掘技术分析相关数据,得到相应的数据挖掘模型.先通过反向传播(Back Propagation,BP)神经网络分析各因素对泊位分配的影响程度,确定出主要因素;然后通过聚类分析中的两步聚类算法进行分析;最终制定集装箱码头泊位分配策略.该方法可为提高集装箱码头生产效率提供帮助. 相似文献
54.
本文通过追溯R&D产业化的演进过程,深入探讨了R&D产业的本质内涵,发现市场导向的R&D产品交易是R&D产业形成的重要标志.R&D产业是以R&D活动为基础,向市场提供具有创意性质的R&D产品作为交易品的经济活动和经济联系.在R&D市场化和产业化过程中,存在两种耦合机制:一是R&D产业价值链中的产品价值创造耦合,另一个是为实现R&D产品创造的产业组织集群创新耦合.我国研发产业发展的战略重点是构建以R&D产业化网络为基础的枢纽-网络结构,区域研发产业发展的政策要点是实施有效的区域知识管理. 相似文献
55.
Elizabeth Hair Tamara Halle Elizabeth Terry-Humen Bridget Lavelle Julia Calkins 《Early childhood research quarterly》2006,21(4):431-454
Two studies examine patterns of school readiness in children at school entry and how these patterns predict first-grade outcomes in a nationally representative sample of first-time kindergartners from the Early Childhood Longitudinal Study—Kindergarten Class of 1998–1999 (N = 17,219). In Study 1, cluster analyses revealed four profiles at kindergarten entry: comprehensive positive development (30%), social/emotional and health strengths (34%), social/emotional risk (13%), and health risk (22.5% of the sample). Study 2 results suggested that children with one of the two “risk” profiles were more likely to be from families with multiple socioeconomic disadvantages. In addition, all four profiles differentially predicted academic and social adjustment in early elementary school. Children with a risk profile performed the worst on all outcomes; children with a comprehensive positive development profile performed the best. The authors discuss the need for early identification of children who may be at risk for entering school with few school readiness strengths. 相似文献
56.
Rosanne Quinnell Elizabeth May Mary Peat 《International Journal of Science Education》2013,35(7):1053-1074
We surveyed first year students at the start and at the end of their first semester of university biology (n?=?285) as to their approaches to study (surface, deep) and their conceptions of biology (fragmented, cohesive). Hierarchical cluster analysis was used to group students who responded similarly to the survey; this resolved four Learner Profiles based on specific combinations of approach to study and conception of biology. By comparing cluster membership at the start and end of the semester we could assess whether students (1) maintained their incoming approach to study and conception of the discipline of biology, i.e. their ‘Learner Profile’ and (2) whether certain Learner Profiles were more persistent than others. Approximately half the student cohort did not alter their approach to study or conceptions of biology by semester's end. Students in the disengaged profile, i.e. who returned mostly negative responses to survey items, appeared the most resistant to changing their Learner Profile; while the greatest migration occurred towards less than desirable learning strategies (particularly to the disengaged profile). We were able to confirm the significant migration patterns by assessing the heterogeneity of each cluster at the start of semester clusters with respect to the students' approaches and conceptions at the end of semester. Thus we present a process to accurately track Learner Profile changes that may tell us more about how we can enhance students' learning and provide a means by which to gather the empirical data to support decisions relating to curriculum change. 相似文献
57.
本文论述了双机热备实验在SAN网络基础课程中的重要性,阐述了利用Pluswell Cluster模拟双机热备实验的优势,并给出了实际的实验环境和步骤. 相似文献
58.
新引进小黑麦的醇溶蛋白遗传多样性分析 总被引:1,自引:0,他引:1
小黑麦作为黑麦中有益基因向小麦转移的桥梁,被广泛用于普通小麦的遗传改良.为了有效利用从国际玉米小麦改良中心引进的183份小黑麦材料,利用酸性聚丙烯酰胺凝胶电泳(A-PAGE)对其醇溶蛋白的遗传多样性进行了分析,结果表明:183份材料共分离出125种不同的带型,39条迁移率不同的谱带,其中只有在ω区的三条带为所有材料共有,其余的36条带都具有多态性,多态性带数占总分离条带数的92.3%,多态性较高;并且以中国春为对照,在小黑麦材料中没有发现与中国春的醇溶蛋白相同的谱带;通过醇溶蛋白的聚类分析可将183份小黑麦材料划分为三大类. 相似文献
59.
Previous team role taxonomies have largely relied on self-report data, have focused on functional roles and have described individual predispositions or personality traits. Instead, this study takes a communicative approach and proposes that team roles are produced, shaped and sustained in communicative behaviors. To identify team roles communicatively, 59 regular organizational meetings were videotaped and analyzed. Cluster analysis revealed five emergent roles: the solution seeker, the problem analyst, the procedural facilitator, the complainer, and the indifferent. In terms of meeting outcomes, solution seekers were beneficial to idea longevity, whereas complainers were harmful for meeting satisfaction and idea longevity. Future research directions and managerial implications are highlighted. 相似文献
60.
The cluster concept has become a popular guideline for regional policies fostering industrial competitiveness and innovativeness based on sectoral specialization and collaboration. This article discusses the issue of effective institutional forms of cluster promotion, juxtaposing two modes: Explicit cluster policies implemented top-down by regional authorities and implicit initiatives that are organized and financed bottom-up by groups of firms. Both approaches are compared from a theoretical and empirical perspective, pointing out differing patterns of effects, relative strengths and weaknesses. Realization of these differences, considered in relation to regional preconditions and objectives, may help to adequately institutionalize cluster support. 相似文献