全文获取类型
收费全文 | 3951篇 |
免费 | 89篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 38篇 |
综合类 | 1篇 |
化学工业 | 716篇 |
金属工艺 | 76篇 |
机械仪表 | 63篇 |
建筑科学 | 159篇 |
矿业工程 | 19篇 |
能源动力 | 54篇 |
轻工业 | 303篇 |
水利工程 | 23篇 |
石油天然气 | 28篇 |
无线电 | 217篇 |
一般工业技术 | 581篇 |
冶金工业 | 1172篇 |
原子能技术 | 43篇 |
自动化技术 | 558篇 |
出版年
2022年 | 28篇 |
2021年 | 66篇 |
2020年 | 36篇 |
2019年 | 59篇 |
2018年 | 46篇 |
2017年 | 67篇 |
2016年 | 51篇 |
2015年 | 43篇 |
2014年 | 68篇 |
2013年 | 234篇 |
2012年 | 130篇 |
2011年 | 166篇 |
2010年 | 120篇 |
2009年 | 134篇 |
2008年 | 161篇 |
2007年 | 138篇 |
2006年 | 140篇 |
2005年 | 136篇 |
2004年 | 127篇 |
2003年 | 108篇 |
2002年 | 86篇 |
2001年 | 84篇 |
2000年 | 67篇 |
1999年 | 89篇 |
1998年 | 153篇 |
1997年 | 85篇 |
1996年 | 73篇 |
1995年 | 85篇 |
1994年 | 68篇 |
1993年 | 78篇 |
1992年 | 44篇 |
1991年 | 33篇 |
1990年 | 57篇 |
1989年 | 55篇 |
1988年 | 46篇 |
1987年 | 60篇 |
1986年 | 49篇 |
1985年 | 61篇 |
1984年 | 56篇 |
1983年 | 52篇 |
1982年 | 43篇 |
1981年 | 58篇 |
1980年 | 39篇 |
1979年 | 58篇 |
1978年 | 55篇 |
1977年 | 49篇 |
1976年 | 38篇 |
1975年 | 38篇 |
1974年 | 43篇 |
1973年 | 27篇 |
排序方式: 共有4051条查询结果,搜索用时 417 毫秒
81.
82.
Agent based simulation architecture for evaluating operational policies in transshipping containers 总被引:1,自引:0,他引:1
Lawrence Henesey Paul Davidsson Jan A. Persson 《Autonomous Agents and Multi-Agent Systems》2009,18(2):220-238
An agent based simulator for evaluating operational policies in the transshipment of containers in a container terminal is
described. The simulation tool, called SimPort, is a decentralized approach to simulating managers and entities in a container
terminal. Real data from two container terminals are used as input for evaluating eight transshipment policies. The policies
concern the sequencing of ships, berth allocation, and stacking rule. They are evaluated with respect to a number of aspects,
such as, turn-around time for ships and traveled distance of straddle carriers. The simulation results indicate that a good
choice in yard stacking and berthing position policies can lead to faster ship turn-around times. For instance, in the terminal
studied the Overall-Time-Shortening policy offers fast turn-around times when combined with a Shortest-Job-First sequencing
of arriving ships. 相似文献
83.
This book warns readers about the proliferation of data capture and the degree to which we're tracked and traced on the Web. In ten heavily illustrated chapters, the author explains how our data are captured, retained, and shared (often for a price) with third parties. The author dedicates a chapter to ways of addressing the threat. He suggests methods for controlling cookies, diffusing or eliminating disclosures, encrypting important data, protecting a network address, and using policy as well as technical devices to minimize data capture and retention. 相似文献
84.
Giannakis E Samuel CS Hewitson TD Boon WM Macris M Reeve S Lawrence J Ian Smith A Tregear GW Wade JD 《Proteomics. Clinical applications》2009,3(10):1211-1224
Kidney failure is a major health problem worldwide. Patients with end-stage renal disease require intensive medical support by dialysis or kidney transplantation. Current methods for diagnosis of kidney disease are either invasive or insensitive, and renal function may decline by as much as 50% before it can be detected using current techniques. The goal of this study was, therefore, to identify biomarkers of kidney disease (associated with renal fibrosis) that can be used for the development of a non-invasive clinical test for early disease detection. We utilized two protein-profiling technologies (SELDI-TOF MS and 2-D) to screen the plasma and kidney proteome for aberrantly expressed proteins in an experimental mouse model of unilateral uretric obstruction, which mimics the pathology of human renal disease. Several differentially regulated proteins were detected at the plasma level of day-3-obstructed animals, which included serum amyloid A1, fibrinogen α, haptoglobin precursor protein, haptoglobin and major urinary proteins 11 and 8. Differentially expressed proteins detected at the tissue level included ras-like activator protein 2, haptoglobin precursor protein, malate dehydrogenase, α enolase and murine urinary protein (all p<0.05 versus controls). Immunohistochemistry was used to confirm the up-regulation of fibrinogen. Interestingly, these proteins are largely separated into four major classes: (i) acute-phase reactants (ii) cell-signaling molecules (iii) molecules involved in cell growth and metabolism and (iv) urinary proteins. These results provide new insights into the pathology of obstructive nephropathy and may facilitate the development of specific assay(s) to detect and monitor renal fibrosis. 相似文献
85.
86.
Lawrence Power Andrew Charlesworth Antony Galton 《Information & Communications Technology Law》1994,3(1):85-96
Electronic Finance Law Chris Reed, 1993 Hemel Hempstead: Woodhead‐Faulkner. 450 pp. £50.00
Introduction to Computer Law, 2nd Edn David I. Bainbridge, 1993 London: Pitman £18.99
Deontic Logic in Computer Science: normative system specification John‐Jules CH. Meyer & Roel J. Wieringa, 1993 London: John Wiley £34.95, xiv + 317pp. 相似文献
87.
Janina Wirth Kory K. Green Megan O'Connor Shuang F. Lim 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(6)
Upconverting nanoparticles show potential applications in the field of photovoltaics and array‐based detection devices. While fluorescence enhancement using interference of incident radiation is well known in Stokes‐shift type systems such as fluorescent dyes; the effect of such interference geometry in nonlinear Anti‐Stokes type emission, such as in upconversion rare earth photophysics is demonstrated for the first time. This work describes in detail the influence of the interference modulation on both the excitation (interion energy transfer) and radiative decay with nonradiative decay processes active between emissive levels. These effects are illustrated in the thickness dependence of the decay rate and rise time. Single particle upconverted spectra and time‐resolved measurements show concurrent optimization of the infrared absorption and emission at 540 and 650 nm, with an average enhanced emission of 20 times at λ = 540 and 45 times at λ = 650 nm, dependent on the interference layer thickness and on the excitation intensity. The experimental results are correlated with finite element modeling. Both experiments and calculations show emission enhancement at an interference layer thickness of about 740 ± 20 nm, where such tolerance and the planar design, leads to ease in implementation in applications. 相似文献
88.
Dong-Jun Kwon Jin-Yeong Choi Pyeong-Su Shin K. Lawrence DeVries 《Advanced Composite Materials》2016,25(6):515-524
Dispersion and shape of nanoparticles, as well as interfacial conditions, add significantly to difficulties in composite manufacture. In the work reported here, an innovative method of recycling composites using out-of-date prepreg was investigated in which the carbon nanotube (CNT) on the prepreg was optimally coated. Nanocomposites utilizing the out-of-date prepreg were coated with CNT and fabricated by a sheet molding method. CNT nanofillers were observed to be uniformly dispersed on epoxy prepreg by spray coating. The mechanical and interfacial properties of these CNT coated nanocomposites were improved over those of more conventionally manufactured carbon fiber/epoxy composites. The CNT nanofillers were embedded at the epoxy and fiber interface, as a result of etching of the epoxy prepreg surface by a CNT dispersion solution which enhanced interfacial reactivity. 相似文献
89.
Derrick K. Rollins Nidhi Bhandari Jim Kleinedler Kaylee Kotz Amber Strohbehn Lindsay Boland Megan Murphy Dave Andre Nisarg Vyas Greg Welk Warren E. Franke 《Journal of Process Control》2010,20(1):95-107
The goal of this work is to present a causation modeling methodology with the ability to accurately infer blood glucose levels using a large set of highly correlated noninvasive input variables over an extended period of time. These models can provide insight to improve glucose monitoring, and glucose regulation through advanced model-based control technologies. The efficacy of this approach is demonstrated using real data from a type 2 diabetic (T2D) subject collected under free-living conditions over a period of 25 consecutive days. The model was identified and tested using eleven variables that included three food variables as well as several activity and stress variables. The model was trained using 20 days of data and validated using 5 days of data. This gave a fitted correlation coefficient of 0.70 and an average absolute error (AAE) (i.e., the average of the absolute values for the measured glucose concentration minus modeled glucose concentration) of 13.3 mg/dL for the validation data. This AAE result was significantly better than the subject’s personal glucose meter AAE of 15.3 mg/dL for replicated measurements. 相似文献
90.
Nazanin Darbanian Sameer M. Venugopal Shrinivas G. Gopalan David R. Allee Lawrence T. Clark 《Journal of the Society for Information Display》2010,18(5):346-350
Abstract— The development of a flexible, rewritable, non‐volatile memory (NVM) that is implemented on a standard, low‐temperature a‐Si:H process without additional mask steps is reported. This NVM is a part of a flexible‐display system. Each NVM cell is composed of differentially configured thin‐film‐transistors (TFTs). The cell reads out one of two stable states depending on the relative threshold voltages of the differentially configured TFTs. Information is stored in each cell by increasing the threshold voltage of one differential TFT or the other, utilizing the well‐known electrical‐stress degradation intrinsic to a‐Si:H TFTs. The stored information is retained indefinitely with no applied power. A test array of individually addressable NVM cells has been successfully fabricated and tested on flexible stainless‐steel substrates. Read and write operation, as well as preliminary reliability measurements, are described. The design is readily scalable to large memory arrays. 相似文献