全文获取类型
收费全文 | 828篇 |
免费 | 25篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 41篇 |
化学工业 | 108篇 |
金属工艺 | 10篇 |
机械仪表 | 19篇 |
建筑科学 | 10篇 |
能源动力 | 38篇 |
轻工业 | 38篇 |
水利工程 | 2篇 |
无线电 | 143篇 |
一般工业技术 | 134篇 |
冶金工业 | 98篇 |
原子能技术 | 15篇 |
自动化技术 | 201篇 |
出版年
2023年 | 4篇 |
2022年 | 16篇 |
2021年 | 12篇 |
2020年 | 13篇 |
2019年 | 14篇 |
2018年 | 25篇 |
2017年 | 15篇 |
2016年 | 21篇 |
2015年 | 18篇 |
2014年 | 13篇 |
2013年 | 39篇 |
2012年 | 31篇 |
2011年 | 35篇 |
2010年 | 25篇 |
2009年 | 25篇 |
2008年 | 28篇 |
2007年 | 25篇 |
2006年 | 22篇 |
2005年 | 17篇 |
2004年 | 18篇 |
2003年 | 14篇 |
2002年 | 17篇 |
2001年 | 13篇 |
2000年 | 7篇 |
1999年 | 20篇 |
1998年 | 42篇 |
1997年 | 40篇 |
1996年 | 14篇 |
1995年 | 12篇 |
1994年 | 16篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 15篇 |
1990年 | 10篇 |
1989年 | 11篇 |
1988年 | 18篇 |
1987年 | 13篇 |
1986年 | 12篇 |
1985年 | 23篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 15篇 |
1981年 | 19篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 7篇 |
1973年 | 5篇 |
1971年 | 4篇 |
排序方式: 共有857条查询结果,搜索用时 15 毫秒
1.
Telecommunication Systems - Energy saving in User Equipment (UE) is one of the important issues for limited sources of power in the device. It is critical for the UE to maximize its energy... 相似文献
2.
Aishwarya
Srivastava Siddhant Aggarwal Amy Apon Edward Duffy Ken Kennedy Andre Luckow Brandon Posey Marcin Ziolkowski 《Software》2020,50(6):868-898
We investigate the challenges of building an end-to-end cloud pipeline for real-time intelligent visual inspection system for use in automotive manufacturing. Current methods of visual detection in automotive assembly are highly labor intensive, and thus prone to errors. An automated process is sought that can operate within the real-time constraints of the assembly line and can reduce errors. Components of the cloud pipeline include capture of a large set of high-definition images from a camera setup at the assembly location, transfer and storage of the images as needed, execution of object detection, and notification to a human operator when a fault is detected. The end-to-end execution must complete within a fixed time frame before the next car arrives in the assembly line. In this article, we report the design, development, and experimental evaluation of the tradeoffs of performance, accuracy, and scalability for a cloud system. 相似文献
3.
Chinh Ngo Radhika Mehta Kanchan Aggarwal Audrey G. Fikes Dr. Ines C. Santos Dr. Sylvester M. Greer Prof. Dr. Emily L. Que 《Chembiochem : a European journal of chemical biology》2019,20(8):1003-1007
One-third of all proteins are estimated to require metals for structural stability and/or catalytic activity. Desthiobiotin probes containing metal binding groups can be used to capture metalloproteins with exposed active-site metals under mild conditions so as to prevent changes in metallation state. The proof-of-concept was demonstrated with carbonic anhydrase (CA), an open active site, Zn2+-containing protein. CA was targeted by using sulfonamide derivatives. Linkers of various lengths and structures were screened to determine the optimal structure for capture of the native protein. The optimized probes could selectively pull down CA from red blood cell lysate and other protein mixtures. Pull-down of differently metallated CAs was also investigated. 相似文献
4.
The relatively low capacitance of negative electrodes, as compared to the capacitance of advanced positive electrodes, poses a serious problem, since this limits the development of asymmetric supercapacitor (SC) devices with a large voltage window and enhanced power-energy characteristics. We fabricate negative SC electrodes with a high capacitance that match the capacitance of advanced positive electrodes at similar active mass loadings, as high as 37?mg?cm?2. Cyclic voltammetry, impedance spectroscopy, galvanostatic charge-discharge data and the power-energy characteristics of the asymmetric SC device exhibit good electrochemical performance for a voltage window of 1.6?V. Our approach involves the development and application of particle extraction through liquid-liquid interface (PELLI) methods, new extraction mechanisms and efficient extractors to synthesize α-FeOOH and β-FeOOH electrode materials. The use of PELLI allows agglomerate-free processing of powders, which facilitates their efficient mixing with multiwalled carbon nanotubes (MWCNT) and allows improved electrolyte access to the particle surface. Experiments to determine the properties of FeOOH-MWCNT composites provided insight into the influence of the electrode material and the structure of extractor molecules on the composite properties. The highest capacitance of 5.86?F?cm?2 for negative electrodes and low impedance were achieved using α-FeOOH-MWCNT composites and a 16-phosphonohexadecanoic acid (PHDA) extractor. This extractor allows adsorption on particles, not only at the liquid-liquid interface, but also in the bulk aqueous phase and can potentially be used as a capping agent for particle synthesis and as an extractor in the PELLI method. 相似文献
5.
Tanu Sharma Sanjeev Aggarwal Shyam Kumar V. K. Mittal P. C. Kalsi V. K. Manchanda 《Journal of Materials Science》2007,42(4):1127-1130
The UV-Visible absorption spectra of virgin and gamma irradiated (20–800 kGy) CR-39 polymer have been deduced by using Shimadzu
Double beam Double Monochromator UV-Visible Spectrophotometer (UV-2550). The existence of the peaks, their shifting and broadening
as a result of gamma irradiation has been discussed. Finally the indirect and direct band gap in virgin and gamma irradiated
CR-39 has been determined. The values of indirect band gap have been found to be lower than the corresponding values of direct
band gap. 相似文献
6.
7.
Zone 3 of a distance relay is used to provide the remote backup protection in case of the failure of the primary protection. However, the risk of maloperation under stressed conditions such as heavy loading, voltage, and transient instability is quite high. Zone 3 is used in combination with the derivatives of the voltage and current, etc. to prevent maloperation. At times, the impedance characteristics that restrict the tripping area of relay are used to avoid maloperation due to load encroachment. This work presents a novel zone 3 scheme based on combining the steady-state components (i.e., 60 Hz) and the transient components (TCs) using a state diagram that visualizes the sequence of studies that emanate from the sequence of events. The simulation results show that the novel zone 3 distance relay elements using the proposed method operate correctly for the various events. 相似文献
8.
Sanghera J.S. Nguyen V.Q. Pureza P.C. Kung F.H. Miklos R. Aggarwal I.D. 《Lightwave Technology, Journal of》1994,12(5):737-741
Improved purification and processing techniques have been utilized to fabricate Ge30As10Se30Te30 glass fibers with a minimum loss of O.11 dB/m at 6.6 μm. This is the lowest loss reported for any telluride glass fiber in the infrared region. Furthermore, the fibers exhibit less than 1 dB/m loss between 5.25 and 9.5 μm 相似文献
9.
Mitiche A. Seida S. Aggarwal J.K. 《IEEE transactions on pattern analysis and machine intelligence》1988,10(4):594-599
The problem of computing structure and motion from the observation of points in two distinct images of a scene is considered. The proposed method explicitly utilizes the principle of conservation of distance during rigid-body motion. The formulation is such that it separates the problem of estimating object position from that of determining motion parameters. The equations of invariance of distance for a rigid body are solved for the points' position in space. When these coordinates in space are known, motion parameters are computed in a simple and straightforward manner. Examples are given to illustrate the efficiency of the algorithm 相似文献
10.
John M. Jewell James Jaganathan Ishwar D. Aggarwal 《Journal of the American Ceramic Society》1991,74(4):788-796
The effect of controlled heterogeneous nucleation by platinum on the crystallization of a ZrF4 -BaF2 -LaF3 -AlF3 -NaF (ZBLAN) glass was studied. Various levels of platinum were incorporated into this glass by a combination of PtCl2 -doping and melting-atmosphere variation. The effect of doping levels and melting conditions on the incorporation of platinum and the subsequent nucleation of crystals was studied by optical microscopy, scanning electron microscopy, differential scanning calorimetry (DSC), and X-ray diffraction. Increased platinum in the glass resulted in an increased number of nucleation sites for the growth of β-ZrF4 -BaF2 crystals. Analysis of isothermal and ramp-rate DSC measurements indicated that the crystallization of this glass changed from surface controlled to bulk controlled with an increased number of nuclei. This was confirmed by optical microscopy. In addition, Avrami analysis of the isothermal crystallization data gave an accurate approximation of the number of nuclei in the glass. 相似文献