全文获取类型
收费全文 | 13424篇 |
免费 | 430篇 |
国内免费 | 493篇 |
专业分类
教育 | 9379篇 |
科学研究 | 2250篇 |
各国文化 | 110篇 |
体育 | 550篇 |
综合类 | 855篇 |
文化理论 | 22篇 |
信息传播 | 1181篇 |
出版年
2024年 | 8篇 |
2023年 | 97篇 |
2022年 | 160篇 |
2021年 | 297篇 |
2020年 | 418篇 |
2019年 | 351篇 |
2018年 | 293篇 |
2017年 | 281篇 |
2016年 | 354篇 |
2015年 | 403篇 |
2014年 | 431篇 |
2013年 | 854篇 |
2012年 | 985篇 |
2011年 | 976篇 |
2010年 | 532篇 |
2009年 | 662篇 |
2008年 | 929篇 |
2007年 | 1071篇 |
2006年 | 1169篇 |
2005年 | 972篇 |
2004年 | 828篇 |
2003年 | 621篇 |
2002年 | 466篇 |
2001年 | 318篇 |
2000年 | 258篇 |
1999年 | 134篇 |
1998年 | 88篇 |
1997年 | 84篇 |
1996年 | 72篇 |
1995年 | 41篇 |
1994年 | 45篇 |
1993年 | 38篇 |
1992年 | 32篇 |
1991年 | 21篇 |
1990年 | 15篇 |
1989年 | 21篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
LIU Peng XIA Bing-jie TENG Zhao-wei 《浙江大学学报(A卷英文版)》2007,8(4):631-637
Floorplan, clock network and power plan are crucial steps in deep sub-micron system-on-chip design. A novel di- agonal floorplan is integrated to enhance the data sharing between different cores in system-on-chip. Custom clock network con- taining hand-adjusted buffers and variable routing rules is constructed to realize balanced synchronization. Effective power plan considering both IR drop and electromigration achieves high utilization and maintains power integrity in our MediaSoC. Using such methods, deep sub-micron design challenges are managed under a fast prototyping methodology, which greatly shortens the design cycle. 相似文献
162.
提供电子转移反应实验研究的实验装置及技术,依此可获得电子转移数、式电极电势、式异相电子转移速率常数、电子传递系数及还原态和氧化态的扩散系数等一系列重要的电化学参数。还可依此为基础设计出新颖、实用的教学实验。 相似文献
163.
课程改革中教师关注阶段理论的研究述评 总被引:4,自引:0,他引:4
本文介绍了"关注阶段"的理论架构与评定方法,回顾并分析了它在美国、比利时、荷兰、香港以及澳大利亚等文化情境中的运用与发展.在我国新课程改革背景下进行关注阶段研究不仅有利于我们了解新课程实施情况,而且有助于这一理论自身的发展. 相似文献
164.
养老基金的投资面临多种风险,要实现其保值增值,必须进行风险度量和监控。VaR模型作为一种新的金融风险管理工具,因其有别于传统的金融风险管理工具的特点,在西方受到广泛青睐。探讨该模型在我国养老基金投资风险控制中的应用。 相似文献
165.
HUANG Biao YAN Guo-zheng LI Qian-ru 《浙江大学学报(A卷英文版)》2007,8(10):1560-1567
Antenna is very crucial to radiotelemetry capsules which can measure the physiological parameters of the gastroin- testinal (GI) tract. The objective of this paper is to design a novel spiral slots microstrip patch antenna for the radiotelemetry capsules communicating with external recorder at 915 MHz located in ISM (Industry, Science, and Medical) bands. The microstrip patch antenna is designed and evaluated using the finite-difference time-domain (FDTD) method. Return loss characteristics and the effect of the human body on resonant frequency are analyzed, and the performances of radiation patterns at different positions of the human alimentary tract are also estimated. Finally, specific absorption rate (SAR) computations are performed, and the peak 1-g and 10-g SAR values are calculated. According to the peak SAR values, the maximum delivered power for the designed antenna was found so that the SAR values of the antenna satisfy the ANSI (American National Standards Institute) limitations. 相似文献
166.
AbstractThis study sought to determine if human papillomavirus (HPV) vaccination rates are associated with teaching requirements for abstinence in state sex education laws and policies. A cross-sectional analysis was conducted assessing the association between abstinence education legislation and HPV vaccination rates in adolescents (aged 13–17?years). After adjustment for insurance coverage and household income, the level of abstinence education was not significantly associated with vaccination rates. However, a higher percentage of individuals uninsured was significantly and negatively associated with the vaccination rate. This suggests that HPV vaccination rates are associated with insurance coverage, but not with the degree to which sex education laws or policies emphasize abstinence. 相似文献
167.
为什么人文环境和地理条件都不占优势的山西,在一个特定的历史时期,成为中国商界、金融界巨擘的摇篮?除去边境军事形势所形成的巨大市场和开中制的实施提供的商机外,传统文化以及地缘文化的影响也具有十分重要的意义。 相似文献
168.
自然手语与规约手语之研究 总被引:1,自引:3,他引:1
目前中国大多数聋校是以手语为主要教学语言。本文从手语的基本特点入手 ,把手语分为自然手语和规约手语并具体分析了两者的特点 ,进而就如何在课堂教学中运用好自然手语和规约手语 ,以提高课堂教学效率 ,促进聋生语言能力的发展以及以建立聋人手语语料厍。 相似文献
169.
1 Introduction SMP (symmetricmulti processing)andMPP (mas sivelyparallelprocessing)arethetwotypesofstruc tureofparallelcomputing . Symmetricmulti processingsystemshavemultipleCPUsattachedtothesamebusandsharingRAM .Massivelyparallelprocessingisthecooperated pro cessingofaprogrambymultipleprocessorsthatworkondifferentpartsoftheprogram ,witheachprocessorusingitsownoperatingsystemandmemory .ThechoicebetweenSMPandMPPdependsonthenatureoftheproblembeingsolved .Iftheproblemcanbeeasilypartit… 相似文献
170.
The effects of photoperiod and light intensity on flowering in Mat Rush cv. Gangshan 3 were studied. The results showed that
treatments with longer day length stimulated flowering significantly and increased stem flowering percentage (SFP). Plants
treated with low light intensity at early stage had substantially reduced florets per cyme, SFP, tillers per plant and stem
length. At middle and late stage, low light intensity significantly reduced SFP. The principal climatic factors affecting
SFP were as follows: mean temperatures (MT) of the third ten-day period (TDP) in December and of the second TDP in February,
actual sunlight hours (SH) of the third TDP in February and precipitation of the third TDP in March. A nonlinear simulation
model for SFP was established with experimental results and corresponding climatic data (see Eq. (2)).
Simulation by the above equation yielded values the same as those observed from 1992 to 2000, indicating its accuracy in describing
the relationship between flowering and light and temperature conditions. The interaction between vernalization and SH is also
discussed in this paper.
Project (No. 981105) supported by the Ningbo City Science Foundation, China 相似文献