全文获取类型
收费全文 | 636篇 |
免费 | 21篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 17篇 |
综合类 | 1篇 |
化学工业 | 101篇 |
金属工艺 | 32篇 |
机械仪表 | 31篇 |
建筑科学 | 27篇 |
能源动力 | 29篇 |
轻工业 | 35篇 |
水利工程 | 5篇 |
无线电 | 73篇 |
一般工业技术 | 106篇 |
冶金工业 | 43篇 |
自动化技术 | 159篇 |
出版年
2023年 | 13篇 |
2022年 | 21篇 |
2021年 | 21篇 |
2020年 | 19篇 |
2019年 | 14篇 |
2018年 | 26篇 |
2017年 | 23篇 |
2016年 | 21篇 |
2015年 | 22篇 |
2014年 | 26篇 |
2013年 | 32篇 |
2012年 | 25篇 |
2011年 | 36篇 |
2010年 | 25篇 |
2009年 | 29篇 |
2008年 | 20篇 |
2007年 | 23篇 |
2006年 | 20篇 |
2005年 | 14篇 |
2004年 | 15篇 |
2003年 | 19篇 |
2002年 | 15篇 |
2001年 | 8篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1998年 | 18篇 |
1997年 | 11篇 |
1996年 | 9篇 |
1995年 | 11篇 |
1994年 | 13篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有659条查询结果,搜索用时 515 毫秒
41.
Silicon - In this study, we present an ambipolar conduction and RF stability performance for a Germanium Source Dual Halo Dual Dielectric Triple Material Surrounding Gate Tunnel FET... 相似文献
42.
Wireless Networks - Mobile data offloading is a current-day networking paradigm to channelize certain fraction of the cellular data traffic over unlicensed spectrum of WiFi. In this paper, we... 相似文献
43.
Viswanath Venkatesh Tracy Ann Sykes Srinivasan Venkatraman 《Information Systems Journal》2014,24(3):249-269
Electronic government (e‐Government) is one of the most important ways to bridge the digital divide in developing countries. We develop a model of e‐Government portal use. We use various individual characteristics, namely demographics and personality, as predictors of e‐Government portal use. Specifically, our predictors were (1) gender, age, income and education; (2) the Big Five personality characteristics, i.e. extraversion, neuroticism, conscientiousness, agreeableness and openness to experience; and (3) personal innovativeness with information technology. We conducted a field study in a village in India. We collected data from over 300 heads of household. We found support for our model, with most variables being significant and explaining 40% of the variance in e‐Government portal use. 相似文献
44.
S.G. Venkatesh S.K. Ayyaswamy S. Raja Balachandar 《Computers & Mathematics with Applications》2012,63(8):1287-1295
The aim of this work is to study the Legendre wavelets for the solution of initial value problems of Bratu-type, which is widely applicable in fuel ignition of the combustion theory and heat transfer. The properties of Legendre wavelets together with the Gaussian integration method are used to reduce the problem to the solution of nonlinear algebraic equations. Also a reliable approach for convergence of the Legendre wavelet method when applied to a class of nonlinear Volterra equations is discussed and an error estimation for the proposed method is also introduced. Illustrative examples have been discussed to demonstrate the validity and applicability of the technique and the results have been compared with the exact solution. We finally show the high accuracy and efficiency of the proposed method. 相似文献
45.
Many researchers in academia and industries are interested in reducing particle sizes from few sub-micrometers to nano-meter levels. These nano-particles find application in several areas including ceramics, paints, cosmetics, microelectronics, sensors, textiles and biomedical, etc. This article reviews the present state of the art for solid state synthesis of mineral nano-particles by wet milling, including their operating variables such as ball size, solid mass fraction and suspension stability. This article concludes and recommends with a critical discussion of nano-particles synthesis and a few common strategies to overcome stability issues. 相似文献
46.
Sunil Kumar Gupta Dinh Phung Brett Adams Svetha Venkatesh 《Data mining and knowledge discovery》2013,26(1):57-97
Joint modeling of related data sources has the potential to improve various data mining tasks such as transfer learning, multitask clustering, information retrieval etc. However, diversity among various data sources might outweigh the advantages of the joint modeling, and thus may result in performance degradations. To this end, we propose a regularized shared subspace learning framework, which can exploit the mutual strengths of related data sources while being immune to the effects of the variabilities of each source. This is achieved by further imposing a mutual orthogonality constraint on the constituent subspaces which segregates the common patterns from the source specific patterns, and thus, avoids performance degradations. Our approach is rooted in nonnegative matrix factorization and extends it further to enable joint analysis of related data sources. Experiments performed using three real world data sets for both retrieval and clustering applications demonstrate the benefits of regularization and validate the effectiveness of the model. Our proposed solution provides a formal framework appropriate for jointly analyzing related data sources and therefore, it is applicable to a wider context in data mining. 相似文献
47.
Venkatesh Ramakrishnan Tobias Veerkamp Gerd Ascheid Marc Adrat Markus Antweiler 《Journal of Signal Processing Systems》2012,69(1):41-53
Matrix decomposition of the channel matrix in the form of QR decomposition (QRD) is needed for advanced multiple input and multiple output (MIMO) demapping algorithms like sphere decoder. Due to the computation-intensive nature of the QRD, its implementation has to be highly efficient. Flexibility in several forms, e.g. support for different algorithms, reusability of wireless implementations, portability, etc. is highly sought in wireless devices. The contradictory nature of flexibility and efficiency requires tradeoffs to be made between them in system development. In this paper, we have analyzed such tradeoffs by implementing two minimum mean squared error-sorted QRD algorithms. The algorithms have been implemented in four different methods with varying degree of reusability and in five different forms of portability. The performance of the implementations is evaluated by using the real-time constraints from the LTE standard. For all the implementations, modular equations for accurately estimating the execution time are derived. 相似文献
48.
V. Venkatesh Badri S. Rao Gopalakrishnan Srilakshmi N. C. Thirumalai M. A. Ramaswamy 《Applied Solar Energy》2017,53(3):258-266
In Central Receiver Systems (CRSs), thousands of heliostats track the sunrays and reflect beam radiation on to a receiver surface. The size of the reflected image and the extent of reflection from the heliostats are one of the important criteria that need to be taken into account while designing a receiver, since spillage losses may vary from 2 to 16% of the total losses. The present study aims to determine the size of an external cylindrical receiver, such that the rays reflected from all the heliostats in the field are intercepted. A dimensionless correlation with respect to tower height and receiver size (diameter and height) as a function of heliostat size and its position is discussed in the paper. This correlation could be used as a first-order approximation to estimate the receiver dimensions. When applied to the Ivanpah Solar Electricity Generating Station (ISEGS) plant, the correlation yields satisfactory estimation of receiver dimensions. 相似文献
49.
Roberto Felicetti Pietro G. Gambarova Alberto Meda 《Construction and Building Materials》2009,23(12):3546-3555
The mechanical properties of various steel bars exposed to high temperature (“residual” properties) are experimentally investigated up to 850 °C, with reference to a number of steel and bar types (carbon and stainless steel; quenched and self-tempered bars; hot-rolled and cold-worked bars; smooth and deformed bars). The aim is to clarify to what extent the thermal sensitivity of the different bars affects the ultimate capacity of a typical R/C section subjected to an eccentric axial force, past a fire (“residual” capacity). As usual in the design of R/C sections under combined bending and axial loading, the ultimate behavior is represented through the “M–N envelopes”, where the materials strength decay due to high temperature is taken into account. The results show that quenched and self-tempered bars (QST), very popular in Europe, are more temperature-sensitive above 600 °C than the carbon-steel bars extensively used in the States and nowadays rarely used in Europe. Furthermore, the best response is exhibited by the stainless-steel bars, provided that they are hot rolled, as it is generally the case for medium- and large-diameter bars. Similar conclusions can be drawn for the sections reinforced with the different bar types. 相似文献
50.
Venkat N. Vangaveti Venkatesh M. Shashidhar Catherine Rush Usman H. Malabu Roy R. Rasalam Fiona Collier Bernhard T. Baune Richard L. Kennedy 《Lipids》2014,49(12):1181-1192
Macrophage apoptosis, a key process in atherogenesis, is regulated by oxidation products, including hydroxyoctadecadienoic acids (HODEs). These stable oxidation products of linoleic acid (LA) are abundant in atherosclerotic plaque and activate PPARγ and GPR132. We investigated the mechanisms through which HODEs regulate apoptosis. The effect of HODEs on THP‐1 monocytes and adherent THP‐1 cells were compared with other C18 fatty acids, LA and α‐linolenic acid (ALA). The number of cells was reduced within 24 hours following treatment with 9‐HODE (p < 0.01, 30 μM) and 13 HODE (p < 0.01, 30 μM), and the equivalent cell viability was also decreased (p < 0.001). Both 9‐HODE and 13‐HODE (but not LA or ALA) markedly increased caspase‐3/7 activity (p < 0.001) in both monocytes and adherent THP‐1 cells, with 9‐HODE the more potent. In addition, 9‐HODE and 13‐HODE both increased Annexin‐V labelling of cells (p < 0.001). There was no effect of LA, ALA, or the PPARγ agonist rosiglitazone (1μM), but the effect of HODEs was replicated with apoptosis‐inducer camptothecin (10μM). Only 9‐HODE increased DNA fragmentation. The pro‐apoptotic effect of HODEs was blocked by the caspase inhibitor DEVD‐CHO. The PPARγ antagonist T0070907 further increased apoptosis, suggestive of the PPARγ‐regulated apoptotic effects induced by 9‐HODE. The use of siRNA for GPR132 showed no evidence that the effect of HODEs was mediated through this receptor. 9‐HODE and 13‐HODE are potent—and specific—regulators of apoptosis in THP‐1 cells. Their action is PPARγ‐dependent and independent of GPR132. Further studies to identify the signalling pathways through which HODEs increase apoptosis in macrophages may reveal novel therapeutic targets for atherosclerosis. 相似文献