全文获取类型
收费全文 | 7855篇 |
免费 | 461篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 59篇 |
综合类 | 18篇 |
化学工业 | 1915篇 |
金属工艺 | 184篇 |
机械仪表 | 156篇 |
建筑科学 | 330篇 |
矿业工程 | 27篇 |
能源动力 | 233篇 |
轻工业 | 714篇 |
水利工程 | 112篇 |
石油天然气 | 21篇 |
无线电 | 459篇 |
一般工业技术 | 1690篇 |
冶金工业 | 1207篇 |
原子能技术 | 21篇 |
自动化技术 | 1180篇 |
出版年
2024年 | 12篇 |
2023年 | 64篇 |
2022年 | 139篇 |
2021年 | 208篇 |
2020年 | 168篇 |
2019年 | 201篇 |
2018年 | 220篇 |
2017年 | 208篇 |
2016年 | 244篇 |
2015年 | 187篇 |
2014年 | 314篇 |
2013年 | 563篇 |
2012年 | 467篇 |
2011年 | 675篇 |
2010年 | 453篇 |
2009年 | 423篇 |
2008年 | 475篇 |
2007年 | 438篇 |
2006年 | 366篇 |
2005年 | 326篇 |
2004年 | 267篇 |
2003年 | 251篇 |
2002年 | 229篇 |
2001年 | 114篇 |
2000年 | 102篇 |
1999年 | 101篇 |
1998年 | 91篇 |
1997年 | 91篇 |
1996年 | 76篇 |
1995年 | 84篇 |
1994年 | 81篇 |
1993年 | 56篇 |
1992年 | 67篇 |
1991年 | 27篇 |
1990年 | 31篇 |
1989年 | 42篇 |
1988年 | 42篇 |
1987年 | 40篇 |
1986年 | 35篇 |
1985年 | 54篇 |
1984年 | 45篇 |
1983年 | 41篇 |
1982年 | 40篇 |
1981年 | 25篇 |
1980年 | 28篇 |
1979年 | 20篇 |
1978年 | 21篇 |
1977年 | 18篇 |
1976年 | 17篇 |
1975年 | 11篇 |
排序方式: 共有8326条查询结果,搜索用时 15 毫秒
91.
Ronald S. Cok John W. Hamer Christopher A. Bower Etienne Menard Salvatore Bonafede 《Journal of the Society for Information Display》2011,19(4):335-341
Abstract— Small integrated circuits of crystalline silicon (chiplets) transfer‐printed onto a flat‐panel‐display substrate provide greatly improved electrical performance and uniformity in active‐matrix organic light‐emitting‐diode (OLED) displays. The integrated circuits are formed in high‐performance crystalline silicon using conventional photolithographic processes and then transfer‐printed onto a substrate using a stamp that transfers hundreds or thousands of chiplets at once. The chiplets are connected to an external controller and to pixel elements using conventional photolithographic substrate processing methods. Active‐matrix OLED (AMOLED) displays using transfer‐printed chiplets have good yields, excellent uniformity, and electrical performance and are thermally robust. 相似文献
92.
Morrill JA Biggs JH Bowman CN Stansbury JW 《Journal of molecular graphics & modelling》2011,29(5):763-772
The photoinitiated polymerization of (meth)acrylate monomers bearing novel carbamate functionality exhibits significantly greater reaction rate when compared to more traditional acrylate monomers undergoing similar polymerization. This unusually fast reactivity has been the subject of much investigation. In order to suggest an explanatory mechanism for the enhanced polymerization rates we have conducted quantitative structure-activity relationship investigations of these novel monomers. These studies have resulted in statistically sound models with coefficients of multiple determination of R(2)>0.93. Principal component and k nearest neighbor similarity analysis were also conducted on the multiple regression models. These results are discussed in light of published experimental investigations of the photopolymerization reactivity of the novel monomers. 相似文献
93.
Medium-sized, open-participation Open Source Software (OSS) projects do not usually perform explicit software process improvement
on any routine basis. It would be useful to understand how to get such a project to accept a process improvement proposal
and hence to perform process innovation. We want to determine an effective and feasible qualitative research method for studying
the above question. We present (narratively) a case study of how we worked towards and eventually found such a research method.
The case involves four attempts at collecting suitable data about innovation episodes (direct participation (twice), polling
developers for episodes, manually finding episodes in mailing list archives) and the adaptation of the Grounded Theory data
analysis methodology. Direct participation allows gathering rather rich data, but does not allow for observing a sufficiently
large number of innovation episodes. Polling developers for episodes did not prove to be useful. Using mailing list archives
to find data to be analyzed is both feasible and effective. We also describe how the data thus found can be analyzed based
on the Grounded Theory Method with suitable adjustments. By-and-large, our findings ought to apply to studying various phenomena
in OSS development processes that are similarly heavyweight and infrequent. However, specific details may block this possibility
and we cannot predict which details that might be. The amount of effort involved in direct participation approaches to qualitative
research can easily be underestimated. Also, survey approaches are not well-suited for many process issues in OSS, because
too few developers are sufficiently process-conscious. An approach based on passive observation is a viable alternative in
the OSS context due to the availability of large amounts of fairly complete archival data. 相似文献
94.
J. Christopher Westland 《Information Technology and Management》2011,12(4):387-408
There is no agreement on how to formally incorporate affective data into statistical analysis and research conclusions. The information systems (IS) literature has recently published several position papers that have established a framework and perspective for using affective technology in IS research though. The frameworks have not been extensively tested, and are likely to evolve over time as empirical studies are conducted, and the validity of the methodologies is confirmed or disproved. A major goal of the current paper is to take the initial steps in translating the frameworks to usable methodologies, with application to improving our understanding of how to make effective empirical tests. This paper also investigates the adoption cycle of one of these technologies—electrodermal response (EDR) technologies—whose incarnation in the polygraph in forensic applications went through a complete adoption cycle in the twentieth century. The use of EDR response data in marketing research and surveys is nascent, but prior experience can help us to forecast and encourage its adoption in new research contexts. This research investigates three key questions: (1) What technology adoption model is appropriate for electrodermal response technology in forensic science? (2) What is the accuracy of affective electrodermal response readings? (3) What information is useful after superimposing affective EDR readings on contemporaneous survey data collection? Affective data acquisition technologies appear to add the most information when survey subjects are inclined to lie and have strong emotional feelings. Such data streams are informative, non-invasive and cost-effective. Informativeness is context-dependent though, and it relies on a complex set of still poorly understood human factors. Survey protocols and statistical analysis methods need to be developed to address these challenges. 相似文献
95.
Antonio Fernández Anta José Luis López-Presa M. Araceli Lorenzo Pilar Manzano Juan Martinez-Romo Alberto Mozo Christopher Thraves 《Theory of Computing Systems》2011,48(1):1-22
In this paper we generalize the Continuous Adversarial Queuing Theory (CAQT) model (Blesa et al. in MFCS, Lecture Notes in
Computer Science, vol. 3618, pp. 144–155, 2005) by considering the possibility that the router clocks in the network are not synchronized. We name the new model Non Synchronized
CAQT (NSCAQT). Clearly, this new extension to the model only affects those scheduling policies that use some form of timing.
In a first approach we consider the case in which although not synchronized, all clocks run at the same speed, maintaining
constant differences. In this case we show that all universally stable policies in CAQT that use the injection time and the
remaining path to schedule packets remain universally stable. These policies include, for instance, Shortest in System (SIS)
and Longest in System (LIS). Then, we study the case in which clock differences can vary over time, but the maximum difference
is bounded. In this model we show the universal stability of two families of policies related to SIS and LIS respectively
(the priority of a packet in these policies depends on the arrival time and a function of the path traversed). The bounds
we obtain in this case depend on the maximum difference between clocks. This is a necessary requirement, since we also show
that LIS is not universally stable in systems without bounded clock difference. We then present a new policy that we call
Longest in Queues (LIQ), which gives priority to the packet that has been waiting the longest in edge queues. This policy
is universally stable and, if clocks maintain constant differences, the bounds we prove do not depend on them. To finish,
we provide with simulation results that compare the behavior of some of these policies in a network with stochastic injection
of packets. 相似文献
96.
The use of digital document management and processing is increasing. Traditional workflows of paper forms are being replaced by electronic workflows of digital documents. These workflows often require multiple signatures to be added to the documents for authorization and/or integrity. We describe examples of digital workflows that illustrate problems with digital signatures: i.e. the use of digital signatures across entire documents results in signatures that can be unnecessarily invalidated by subsequent modification of the document. We propose the use of fragment signatures, which reduce unnecessary invalidation of signatures and enable greater concurrency in workflows. Our approach is document‐centric and does not use a centralized database. We report on an implementation that allows fragment signatures over document fragments as well as the attachment (or embedding) of other documents. This allows collaborative or cooperative editing to occur on parts of a document without disturbing unrelated signatures. We describe the lessons learned from our deployments and offer further ways to embed such signatures into other document types. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
97.
98.
Duncan R. Shaw Christopher P. Holland 《The Journal of Strategic Information Systems》2010,19(4):242-256
The globalisation of markets has led to an increased demand for language translation services that support and enable communication between economic partners. For example, technical documents, software systems, business documents and web sites all need to be translated into multiple languages for individual national markets, and the information that they contain changes periodically. This paper sets out a theoretical framework that describes the architectures of business processes within and between separate firms that are used to support the delivery and management of services. This is done by coordinating the fit between externally generated problem complexity, from customers, and the internally generated complexity of different potential network configuration solutions. The theoretical framework is an architecture of how complexity is generated and managed at the different structural levels and across the different processual stages of an industry. A case study of thebigword, a major international translation services company, illustrates how the framework is applied in practice. The case study analyses the implementation of an electronic market platform which enables the coordination of the different stakeholders involved in the translation services market. These stakeholders include translators, translation services companies and their clients in a global business network. 相似文献
99.
Anneliese A. Andrews Jeff Offutt Curtis Dyreson Christopher J. Mallery Kshamta Jerath Roger Alexander 《Information and Software Technology》2010,52(1):52-66
Web applications are fast becoming more widespread, larger, more interactive, and more essential to the international use of computers. It is well understood that web applications must be highly dependable, and as a field we are just now beginning to understand how to model and test Web applications. One straightforward technique is to model Web applications as finite state machines. However, large numbers of input fields, input choices and the ability to enter values in any order combine to create a state space explosion problem. This paper evaluates a solution that uses constraints on the inputs to reduce the number of transitions, thus compressing the FSM. The paper presents an analysis of the potential savings of the compression technique and reports actual savings from two case studies. 相似文献
100.
Zhang Yuanfang Gill Christopher D. Lu Chenyang 《Parallel and Distributed Systems, IEEE Transactions on》2010,21(3):393-404
Different distributed real-time systems (DRS) must handle aperiodic and periodic events under diverse sets of requirements. While existing middleware such as Real-Time CORBA has shown promise as a platform for distributed systems with time constraints, it lacks flexible configuration mechanisms needed to manage end-to-end timing easily for a wide range of different DRS with both aperiodic and periodic events. The primary contribution of this work is the design, implementation, and performance evaluation of the first configurable component middleware services for admission control and load balancing of aperiodic and periodic event handling in DRS. Empirical results demonstrate the need for, and the effectiveness of, our configurable component middleware approach in supporting different applications with aperiodic and periodic events, and providing a flexible software platform for DRS with end-to-end timing constraints. 相似文献