全文获取类型
收费全文 | 26089篇 |
免费 | 2774篇 |
国内免费 | 1444篇 |
专业分类
电工技术 | 1769篇 |
综合类 | 1858篇 |
化学工业 | 1884篇 |
金属工艺 | 1326篇 |
机械仪表 | 1590篇 |
建筑科学 | 556篇 |
矿业工程 | 390篇 |
能源动力 | 277篇 |
轻工业 | 3685篇 |
水利工程 | 199篇 |
石油天然气 | 892篇 |
武器工业 | 331篇 |
无线电 | 3761篇 |
一般工业技术 | 2082篇 |
冶金工业 | 2632篇 |
原子能技术 | 348篇 |
自动化技术 | 6727篇 |
出版年
2024年 | 199篇 |
2023年 | 542篇 |
2022年 | 892篇 |
2021年 | 997篇 |
2020年 | 957篇 |
2019年 | 726篇 |
2018年 | 653篇 |
2017年 | 810篇 |
2016年 | 809篇 |
2015年 | 969篇 |
2014年 | 1484篇 |
2013年 | 1364篇 |
2012年 | 1846篇 |
2011年 | 2257篇 |
2010年 | 1527篇 |
2009年 | 1455篇 |
2008年 | 1494篇 |
2007年 | 1691篇 |
2006年 | 1526篇 |
2005年 | 1459篇 |
2004年 | 1222篇 |
2003年 | 1004篇 |
2002年 | 825篇 |
2001年 | 612篇 |
2000年 | 458篇 |
1999年 | 385篇 |
1998年 | 330篇 |
1997年 | 297篇 |
1996年 | 238篇 |
1995年 | 225篇 |
1994年 | 193篇 |
1993年 | 149篇 |
1992年 | 114篇 |
1991年 | 87篇 |
1990年 | 87篇 |
1989年 | 75篇 |
1988年 | 72篇 |
1987年 | 24篇 |
1986年 | 35篇 |
1985年 | 37篇 |
1984年 | 23篇 |
1983年 | 17篇 |
1982年 | 17篇 |
1981年 | 9篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1977年 | 11篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1955年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Besides entertainment, games have shown to have the potential to impact a broader variety of cognitive abilities. Research has consistently shown that several aspects in cognition such as visual short-memory, multitasking and spatial skills can be enhanced by game play. In a previous study, it was found that playing Monkey Tales, a game aimed at training arithmetic skills, helped second grade pupils to increase their accuracy in mental calculation as compared to paper exercises. In this follow up study we explore whether traditional methods and game training differ in terms of the cognitive processes that both are able to impact. We incorporated standardized measures of working memory and visuo-motor skills. Additionally, the mathematics game was modified and its contents extracted to allow precise comparison between the gaming and paper exercises condition. Thus each single math exercise, type of question (e.g., multiple choice), quantity and order was perfectly matched in the game training and the traditional training conditions. Gains in arithmetical performance, and self-reported measures of enjoyment were also investigated. We found some evidence suggesting that arithmetic performance enhancement induced by game play and paper exercises differ not only in terms of enjoyment but also of working memory capacity improvements. 相似文献
2.
We investigated the resistive switching characteristics of a polystyrene:ZnO–graphene quantum dots system and its potential application in a one diode-one resistor architecture of an organic memory cell. The log–log I–V plot and the temperature-variable I–V measurements revealed that the switching mechanism in a low-current state is closely related to thermally activated transport. The turn-on process was induced by a space-charge-limited current mechanism resulted from the ZnO–graphene quantum dots acting as charge trap sites, and charge transfer through filamentary path. The memory device with a diode presented a ∼103 ION/IOFF ratio, stable endurance cycles (102 cycles) and retention times (104 s), and uniform cell-to-cell switching. The one diode-one resistor architecture can effectively reduce cross-talk issue and realize a cross bar array as large as ∼3 kbit in the readout margin estimation. Furthermore, a specific word was encoded using the standard ASCII character code. 相似文献
3.
The applicability of the identical elements (IE) model of arithmetic fact retrieval (T. C. Rickard, A. F. Healy, & L. E. Bourne, 1994) to cued recall from episodic (image and sentence) memory was explored in 3 transfer experiments. In agreement with results from arithmetic, speedup following even minimal practice recalling a missing word from an episodically bound word triplet did not transfer positively to other cued recall items involving the same triplet. The shape of the learning curve further supported a shift from episode-based to IE-based recall, extending some models of skill learning to cued recall practice. In contrast with previous findings, these results indicate that a form of representation that is independent of the original episodic memory underlies cued-recall performance following minimal practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
进入21世纪,随着集成电路的发展,SoC(System on Chip)片上系统应运而生。而作为SoC重要组成部分的嵌入式存储器,在SoC中所占的比重正逐步增加,并起着越来越重要的作用,那么嵌入式存储器与独立的存储器芯片在设计上存在着哪些差异?对此本文将以NOR型闪存为例在制造工艺的选取、衍生产品的设计、功耗与噪声、后端功能仿真、测试与修复等方面进行分析和研究。 相似文献
5.
基于TS101的PCI接口高速数据采集系统的设计 总被引:1,自引:0,他引:1
给出了基于TS101和PCI的双通道数据采集处理系统的设计方案。首先介绍了ADI公司新型数字信号处理(DSP)微处理器TS101和FLYBY数据传输模式,阐述了系统结构和工作原理,最后对如何利用TS101的FLYBY接口提高数据采集、存取效率和数据系统的逻辑控制进行了详细的论述。 相似文献
6.
7.
文章分析了影响地震采集系统延迟时间的因素,并根据系统延迟的理论对产生的原因进行了论证.同时对实际生产中的测试方法进行了阐述研究和分析,提出了新的测试方法,并结合实际生产提出了合理性建议. 相似文献
8.
钻井参数仪的模块化设计方法研究 总被引:1,自引:0,他引:1
文章以模块化设计原理为基础,讨论了钻井参数仪的模块划分,模块化设计准则和主要设计内容。采用模块化设计方法、现场设备网络的开放网络和现场总线解决方案设计的钻井参数仪,具有传输信号稳定、可靠性高、抑制噪声能力强、组建现场网络成本低等特点。 相似文献
9.
Barch Deanna M.; Mitropoulou Vivian; Harvey Philip D.; New Antonia S.; Silverman Jeremy M.; Siever Larry J. 《Canadian Metallurgical Quarterly》2004,113(4):556
Research suggests that schizotypal personality disorder (SPD) is a part of the spectrum of schizophrenia-related illnesses. This article hypothesizes that a deficit in the representation and maintenance of context is a core cognitive disturbance in schizophrenia and that SPD individuals should demonstrate context-processing deficits. To test this hypothesis, the authors administered 3 versions of their AX-CPT task, designed to assess context processing, to 35 healthy controls and 26 individuals with DSM-IV SPD. They also administered working memory and selective attention tasks. SPD individuals displayed context representation deficits similar to those found in schizophrenia but did not show the same additional deficits in context maintenance. Context processing was strongly associated with working memory and selective attention performance in the SPD individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
Thirty patients who had undergone either a right or left unilateral temporal lobectomy (14 RTL; 16 LTL) and 16 control participants were tested on a computerized human analogue of the Morris Water Maze. The procedure was designed to compare allocentric and egocentric spatial memory. In the allocentric condition, participants searched for a target location on the screen, guided by object cues. Between trials, participants had to walk around the screen, which disrupted egocentric memory representation. In the egocentric condition, participants remained in the same position, but the object cues were shifted between searches to prevent them from using allocentric memory. Only the RTL group was impaired on the allocentric condition, and neither the LTL nor RTL group was impaired on additional tests of spatial working memory or spatial manipulation. The results support the notion that the right anterior temporal lobe stores long-term allocentric spatial memories. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献