全文获取类型
收费全文 | 2831篇 |
免费 | 30篇 |
国内免费 | 9篇 |
专业分类
教育 | 1960篇 |
科学研究 | 272篇 |
各国文化 | 48篇 |
体育 | 214篇 |
综合类 | 2篇 |
文化理论 | 22篇 |
信息传播 | 352篇 |
出版年
2023年 | 12篇 |
2022年 | 30篇 |
2021年 | 51篇 |
2020年 | 102篇 |
2019年 | 124篇 |
2018年 | 148篇 |
2017年 | 149篇 |
2016年 | 135篇 |
2015年 | 97篇 |
2014年 | 131篇 |
2013年 | 703篇 |
2012年 | 101篇 |
2011年 | 91篇 |
2010年 | 94篇 |
2009年 | 84篇 |
2008年 | 81篇 |
2007年 | 72篇 |
2006年 | 68篇 |
2005年 | 35篇 |
2004年 | 32篇 |
2003年 | 45篇 |
2002年 | 33篇 |
2001年 | 34篇 |
2000年 | 31篇 |
1999年 | 22篇 |
1998年 | 17篇 |
1997年 | 19篇 |
1996年 | 18篇 |
1995年 | 16篇 |
1994年 | 13篇 |
1993年 | 19篇 |
1992年 | 13篇 |
1991年 | 22篇 |
1990年 | 9篇 |
1989年 | 16篇 |
1988年 | 10篇 |
1987年 | 18篇 |
1986年 | 11篇 |
1985年 | 20篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 16篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 13篇 |
1978年 | 11篇 |
1977年 | 5篇 |
1975年 | 7篇 |
1973年 | 6篇 |
1971年 | 6篇 |
排序方式: 共有2870条查询结果,搜索用时 0 毫秒
161.
State and Local governments must develop an overarching legal foundation to manage critical service delivery in an electronic environment. Prior to establishing a foundation, decision-makers must first adopt a philosophy that focuses and harnesses expressions of law and public policy. The research and development community must supports the nation’s efforts with programs designed to aid in the risk assessment process. These programs must focus on identifying better ways to quantify risk, understanding infrastructure interdependency, and measuring cascading damages flowing from service outages. Finally, State and Local leaders should adopt security guidelines for industry and government service providers. Guidelines involve ten well-defined process requirements, all of which must be implemented to provide services online and in a safe and secure manner. 相似文献
162.
H. Lee Swanson Leilani Sez Michael Gerber 《Learning disabilities research & practice》2004,19(4):225-238
This study determined the degree to which the phonological and executive components of memory reflect language‐specific capacities in reading achievement. We tested whether the memory processes in a sample of English‐language learners that played a major role in predicting second‐language acquisition and risk for reading disability (RD) in Grade 1 (Swanson, Sáez, Gerber, & Leafstedt, 2004) also predicted reading performance in Grade 2. The present results showed that Spanish short‐term memory (STM) performance in Grade 1 predicted basic Spanish‐reading skills and Spanish comprehension in Grade 2, whereas Grade 1 English STM performance predicted English vocabulary and English comprehension in Grade 2. More importantly, children at risk for RD in Grade 1 differed from the counterparts in Grade 2 on both English and Spanish measures of reading, whereas their memory deficits were isolated to Spanish STM and working memory (WM). The relationship between language‐specific processes in memory and reading are discussed. 相似文献
163.
164.
165.
166.
167.
168.
169.
170.
In an effort to bring the advantages of television teaching to the maximum number of public schools, particularly those in hilly or sparsely settled parts of the country, a project has been launched to provide airborne transmission of six simultaneous school lesson program. Coverage area is increased approximately 20 to 1 by this means compared to the usual ground station coverage. Airborne transmission is the most economical and effective use of the available (UHF) frequency spectrum. Results already established regarding the use of television as a teaching medium are projected via an airplane flying at 23,000 feet altitude over an area covering parts of six Midwestern States. Educational advantages and problems inherent in ground station TV are intensified in this larger coverage area, and planning is governed accordingly. Technical problems include multiplex transmission of six lessons simultaneously, keeping the airplane on station, accommodation of transmitting equipment in the airplane, and determination of bandwidth for optimum picture quality. 相似文献