全文获取类型
收费全文 | 3314篇 |
免费 | 352篇 |
国内免费 | 392篇 |
专业分类
电工技术 | 74篇 |
技术理论 | 1篇 |
综合类 | 159篇 |
化学工业 | 16篇 |
金属工艺 | 9篇 |
机械仪表 | 119篇 |
建筑科学 | 29篇 |
矿业工程 | 7篇 |
能源动力 | 37篇 |
轻工业 | 6篇 |
水利工程 | 8篇 |
石油天然气 | 3篇 |
武器工业 | 7篇 |
无线电 | 780篇 |
一般工业技术 | 42篇 |
冶金工业 | 23篇 |
原子能技术 | 4篇 |
自动化技术 | 2734篇 |
出版年
2024年 | 6篇 |
2023年 | 14篇 |
2022年 | 24篇 |
2021年 | 24篇 |
2020年 | 25篇 |
2019年 | 21篇 |
2018年 | 49篇 |
2017年 | 44篇 |
2016年 | 57篇 |
2015年 | 84篇 |
2014年 | 154篇 |
2013年 | 175篇 |
2012年 | 236篇 |
2011年 | 303篇 |
2010年 | 236篇 |
2009年 | 220篇 |
2008年 | 283篇 |
2007年 | 347篇 |
2006年 | 304篇 |
2005年 | 331篇 |
2004年 | 228篇 |
2003年 | 229篇 |
2002年 | 187篇 |
2001年 | 115篇 |
2000年 | 106篇 |
1999年 | 47篇 |
1998年 | 42篇 |
1997年 | 37篇 |
1996年 | 31篇 |
1995年 | 22篇 |
1994年 | 20篇 |
1993年 | 17篇 |
1992年 | 9篇 |
1991年 | 3篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1988年 | 8篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
排序方式: 共有4058条查询结果,搜索用时 15 毫秒
1.
2.
提高信道的数据传输效率是人们不断追求的目标之一,也是衡量网络性能的标准之一,从几方面分析总结了为此而采取的各种措施。 相似文献
3.
4.
5.
计算机网络远程通信系统软硬件设计与实现 总被引:1,自引:0,他引:1
本文介绍一种新型远程通信系统,它克服了一般远程通信系统速度慢的缺点,将通信速度提高了80多倍,同时,其硬件比一般远程通信系统简单,成本只有一般远程通信系统的一半左右,进一步提高了新型远程通信系统的性能价格比。在新型系统中精简了远程通信协议,提高了信道有效利用率;采用了各种行之有效的数据压缩算法,并加以改造,使之性能最佳;提供了程序远程透明执行功能,大大提高了系统的响应速度。 相似文献
6.
J Strother Moore 《Formal Aspects of Computing》1994,6(1):60-91
We present a formal model of asynchronous communication between two digital hardware devices. The model takes the form of a function in the Boyer-Moore logic. The function transforms the signal stream generated by one processor into that consumed by an independently clocked processor, given the phases and rates of the two clocks and the communications delay. The model can be used quantitatively to derive concrete performance bounds on communications at ISO protocol level 1 (physical level). We use the model to show that an 18-bit/cell biphase mark protocol reliably sends messages of arbitrary length between two processors provided the ratio of the clock rates is within 5% of unity. 相似文献
7.
Co-evolution as a computational and cognitive model of design 总被引:6,自引:0,他引:6
Co-evolutionary design has been developed as a computational model that assumes two parallel search spaces: the problem space
and the solution space. The design process iteratively searches each space using the other space as the basis for a fitness
function when evaluating the alternatives. Co-evolutionary design can also be developed as a cognitive model of design by
characterizing the way in which designers iteratively search for a design solution, making revisions to the problem specification.
This paper presents the computational model of co-evolutionary design and then describes a protocol study of human designers
looking for evidence of co-evolution of problem specifications and design solutions. The study shows that co-evolutionary
design is a good cognitive model of design and highlights the similarities and differences between the computational model
and the cognitive model. The results show that the two kinds of co-evolutionary design complement each other, having strengths
in different aspects of the design process.
Electronic Publication 相似文献
8.
It has recently been shown that authenticated Byzantine agreement,
in which more than a third of the parties are corrupted, cannot be
securely realized under concurrent or parallel (stateless)
composition. This result puts into question any usage of
authenticated Byzantine agreement in a setting where many
executions take place. In particular, this is true for the whole
body of work of secure multi-party protocols in the case that a
third or more of the parties are corrupted. This is because these
protocols strongly rely on the extensive use of a broadcast
channel, which is in turn realized using authenticated Byzantine
agreement. We remark that it was accepted folklore that the use of
a broadcast channel (or authenticated Byzantine agreement) is
actually essential for achieving meaningful secure multi-party
computation whenever a third or more of the parties are corrupted.
In this paper we show that this folklore is false. We present a
mild relaxation of the definition of secure computation allowing
abort. Our new definition captures all the central security issues
of secure computation, including privacy, correctness and
independence of inputs. However, the novelty of the definition is
in decoupling the issue of agreement from these issues. We
then show that this relaxation suffices for achieving secure
computation in a point-to-point network. That is, we show that
secure multi-party computation for this definition can be achieved
for any number of corrupted parties and without a
broadcast channel (or trusted pre-processing phase as required for
running authenticated Byzantine agreement). Furthermore, this is
achieved by just replacing the broadcast channel in known
protocols with a very simple and efficient echo-broadcast
protocol. An important corollary of our result is the ability to
obtain multi-party protocols that remain secure under composition,
without assuming a broadcast channel. 相似文献
9.
智能同步光网络(ASON)与多业务传送平台(MSTP)固其先进的智能性、可靠性、灵活性而得以发展和运用。本文根据智能光网络与多业务传送平台枝术的发展情况,结合北京通信传送网络的实际情况,探讨北京通信传送网的建设思路. 相似文献
10.
Gijsbert Erkens Jeroen Janssen 《International Journal of Computer-Supported Collaborative Learning》2008,3(4):447-470
Although protocol analysis can be an important tool for researchers to investigate the process of collaboration and communication,
the use of this method of analysis can be time consuming. Hence, an automatic coding procedure for coding dialogue acts was
developed. This procedure helps to determine the communicative function of messages in online discussions by recognizing discourse
markers and cue phrases in the utterances. Five main communicative functions are distinguished: argumentative, responsive, informative, elicitative, and imperative. A total of 29 different dialogue acts are specified and recognized automatically in collaboration protocols. The reliability
of the automatic coding procedure was determined by comparing automatically coded dialogue acts to hand-coded dialogue acts
by a human rater. The validity of the automatic coding procedure was examined using three different types of analyses. First,
an examination of group differences was used (dialogue acts used by female versus male students). Ideally, the coding procedure
should be able to distinguish between groups who are likely to communicate differently. Second, to examine the validity of
the automatic coding procedure through examination of experimental intervention, the results of the automatic coding procedure
of students, with access to a tool that visualizes the degree of participation of each student, were compared to students
who did not have access to this tool. Finally, the validity of the automatic coding procedure of dialogue acts was examined
using correlation analyses. Results of the automatic coding procedure of dialogue acts of utterances (form) were related to
results of a manual coding procedure of the collaborative activities to which the utterances refer (content). The analyses
presented in this paper indicate promising results concerning the reliability and validity of the automatic coding procedure
for dialogue acts. However, limitations of the procedure were also found and discussed. 相似文献