全文获取类型
收费全文 | 1482篇 |
免费 | 56篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 35篇 |
化学工业 | 369篇 |
金属工艺 | 48篇 |
机械仪表 | 36篇 |
建筑科学 | 37篇 |
矿业工程 | 3篇 |
能源动力 | 128篇 |
轻工业 | 52篇 |
水利工程 | 2篇 |
石油天然气 | 8篇 |
无线电 | 145篇 |
一般工业技术 | 317篇 |
冶金工业 | 170篇 |
原子能技术 | 14篇 |
自动化技术 | 178篇 |
出版年
2023年 | 17篇 |
2022年 | 20篇 |
2021年 | 36篇 |
2020年 | 21篇 |
2019年 | 26篇 |
2018年 | 37篇 |
2017年 | 44篇 |
2016年 | 46篇 |
2015年 | 32篇 |
2014年 | 42篇 |
2013年 | 112篇 |
2012年 | 66篇 |
2011年 | 92篇 |
2010年 | 75篇 |
2009年 | 84篇 |
2008年 | 67篇 |
2007年 | 66篇 |
2006年 | 45篇 |
2005年 | 37篇 |
2004年 | 40篇 |
2003年 | 21篇 |
2002年 | 38篇 |
2001年 | 24篇 |
2000年 | 21篇 |
1999年 | 18篇 |
1998年 | 51篇 |
1997年 | 29篇 |
1996年 | 31篇 |
1995年 | 28篇 |
1994年 | 20篇 |
1993年 | 17篇 |
1992年 | 17篇 |
1991年 | 21篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 15篇 |
1987年 | 16篇 |
1986年 | 11篇 |
1985年 | 13篇 |
1984年 | 11篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1980年 | 8篇 |
1979年 | 15篇 |
1978年 | 12篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1975年 | 7篇 |
1962年 | 4篇 |
1960年 | 4篇 |
排序方式: 共有1542条查询结果,搜索用时 421 毫秒
11.
Tanushree Mitra Basu Nirmal Kumar Mahapatra Shyamal Kumar Mondal 《Applied Soft Computing》2012,12(10):3260-3275
The purpose of this paper is two folded. Firstly, the concept of mean potentiality approach (MPA) has been developed and an algorithm based on this new approach has been proposed to get a balanced solution of a fuzzy soft set based decision making problem. Secondly, a parameter reduction procedure based on relational algebra with the help of the balanced algorithm of mean potentiality approach has been used to reduce the choice parameter set in the parlance of fuzzy soft set theory and it is justified to the problems of diagnosis of a disease from the myriad of symptoms from medical science. Moreover the feasibility of this proposed method is demonstrated by comparing with Analytical Hierarchy Process (AHP), Naive Bayes classification method and Feng's method. 相似文献
12.
Impact of communication time delays on
combined LFC and AVR of a multi-area
hybrid system with IPFC-RFBs coordinated
control strategy
下载免费PDF全文
![点击此处可从《电力系统保护与控制》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In this paper, the impact of communication time delays (CTDs) on combined load frequency control (LFC) and
automatic voltage regulation (AVR) of a multi-area system with hybrid generation units is addressed. Investigation
reveals that CTDs have significant effect on system performance. A classical PID controller is employed as a
secondary regulator and its parametric gains are optimized with a differential evolution - artificial electric field
algorithm (DE-AEFA). The superior performance of the presented algorithm is established by comparing with
various optimization algorithms reported in the literature. The investigation is further extended to integration of
redox flow batteries (RFBs) and interline power flow controller (IPFC) with tie-lines. Analysis reveals that IPFC and
RFBs coordinated control enhances system dynamic performance. Finally, the robustness of the proposed control
methodology is validated by sensitivity analysis during wide variations of system parameters and load. 相似文献
13.
Bikramjit Basu T. Venkateswaran Doh-Yeon Kim 《Journal of the American Ceramic Society》2006,89(8):2405-2412
In a recent work, 1 we have reported the optimization of the spark plasma sintering (SPS) parameters to obtain dense nanostructured 3Y-TZP ceramics. Following this, the present work attempts to answer some specific issues: (a) whether ZrO2 -based composites with ZrB2 reinforcements can be densified under the optimal SPS conditions for TZP matrix densification (b) whether improved hardness can be obtained in the composites, when 30 vol% ZrB2 is incorporated and (c) whether the toughness can be tailored by varying the ZrO2 –matrix stabilization as well as retaining finer ZrO2 grains. In the present contribution, the SPS experiments are carried out at 1200°C for 5 min under vacuum at a heating rate of 600 K/min. The SPS processing route enables retaining of the finer t -ZrO2 grains (100–300 nm) and the ZrO2 –ZrB2 composite developed exhibits optimum hardness up to 14 GPa. Careful analysis of the indentation data provides a range of toughness values in the composites (up to 11 MPa·m1/2 ), based on Y2 O3 stabilization in the ZrO2 matrix. The influence of varying yttria content, t -ZrO2 transformability, and microstructure on the properties obtained is discussed. In addition to active contribution from the transformation-toughening mechanism, crack deflection by hard second phase brings about appreciable increment in the toughness of the nanocomposites. 相似文献
14.
In manufacturing industries, the quality of a product depends on the combined effect of multiple input variables working singly or together and therefore attention has been given on process capability indices to shift from single to multivariate domain. In case of multivariable domain the capability to incorporate uncertainties at the time of decision making becomes necessary. Fuzzy system is introduced to take care of this requirement. In this article the process parameters of soap manufacturing industries have been analyzed. The process capability is determined using Fuzzy Inference System rule editor based on a set of justified if then statements as applicable for the process. The data has been collected in linguistic form to derive its process capability, using a set of justified rules and the effect of each factor has been determined using Design of Experiments (DoE) and analysis of variance technique (ANOVA) for improving the soap quality from perspective of its softness. This article ventures to propose a new methodology by integrating Fuzzy with DoE providing better result followed by DoE and Fuzzy Inference system in isolation. 相似文献
15.
In this Account, we explore the role constant curvature structures play in amphiphilic small molecule crystals and extended coordination solids. A constant curvature structure is one in which there is a surface or interface that has the same curvature throughout its surface. Simple examples of such structures contain spheres (micelles), columns, or layers. Yet another family are cubic as is found in the gyroid topology. For amphiphilic systems, there are two domains, one generally hydrophobic and the other hydrophilic. We find that the interfaces between these two domains in small molecule structures resemble those in larger scale systems and adopt topologies related to constant curvature structures. The hydrophobic-to-total volume ratio, a molecular parameter, can be used to predict which type of constant curvature structure is adopted. In the case of three coordinate extended solids, constant curvature plays a role both in the extended net topology and in the hydrophobic-to-hydrophilic interface. 相似文献
16.
Preparation of glycol derivatives of partially hydrogenated soybean oil fatty acids and their potential as lubricants 总被引:1,自引:0,他引:1
Hemendra N. Basu Ellen M. Robley Max E. Norris 《Journal of the American Oil Chemists' Society》1994,71(11):1227-1230
Glycol diesters and mixtures of mono- and diesters have been prepared from methyl esters of partially hydrogenated soybean
oil fatty acids and diethylene, dipropylene, neopentyl and triethylene glycols. The catalyst used in these reactions was a
mixture of calcium acetate/barium acetate (3∶1, w/w). The reactions were carried out under nitrogen with 0.5% catalyst at
temperatures in the range of 190–275°C. Borated esters of mixed mono- and diesters were prepared with 0.33 equivalent of boric
acid per 1.0 equivalent hydroxyl group on the ester. Refractive indices, viscosities, and flash and fire points were determined
for diesters, mixed mono- and diesters, and mixed diesters and borated esters. The viscosities, flash points and fire points
indicate that these esters can be used as a component of lubricating oils. Wear-prevention characteristics of mixed diesters
and borated esters indicated that they can be used as antifriction additives in lubricating oils.
Lecture presented at the joint meeting of the International Society for Fat Research and the American Oil Chemists' Society
in Toronto, May 10, 1992. 相似文献
17.
Filled covulcanizates of elastomer blend comprising natural rubber (NR) and ethylene‐propylene‐diene rubber (EPDM) of commercial importance were successfully prepared by using a multifunctional rubber additive; namely, bis(diisopropyl)thiophosphoryl disulfide (DIPDIS). A Two‐stage vulcanization technique further improved the physicochemical properties of the blend vulcanizates by restricting, through the formation of polar rubber bound intermediates, the migration of curative and filler from lower to highly unsaturated rubber. Scanning electron microscopy studies indicate homogeneity and coherency in the morphology of the two‐stage vulcanizates. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1001–1010, 2002; DOI 10.1002/app.10361 相似文献
18.
D. L. Purcell B. T. McClure J. McDonald Hemendra N. Basu 《Journal of the American Oil Chemists' Society》1996,73(3):381-388
An evaluation of the exhaust emissions from a compression ignition engine for fuels composed of 100 and 30% methyl esters
of soy oil (SME) is described. These fuels were compared with a low-sulfur, petroleum #2 diesel fuel in a Caterpillar 3304,
prechamber, 75 kW diesel engine, operated over heavy- and light-duty transient test cycles developed by the United States
Bureau of Mines. More than 60 h of testing was performed on each fuel. The objective was to determine the influence of the
fuels upon diesel particulate matter (DPM) and gaseous emissions. The effect of a modern diesel oxidation catalyst (DOC) also
was determined in an effort to minimize emissions. Neat SME produced a higher volatile fraction of the DPM, but much less
carbon soot fraction, leading to overall DPM reductions of 23 to 30% for the light- and heavy-duty transients. The DOC further
reduced the volatile fraction and the total DPM. The SME fuel reduced gaseous emissions of CO by 23% and hydrocarbons by over
30% without increasing NOx. The DOC further reduced CO and hydrocarbon levels. Mutagenicity of the SME exhaust was low. Results indicate that SME fuel,
used with a proper DOC, may be a feasible emission reduction technology for underground mines.
References to specific products do not imply endorsement by the U.S. Bureau of Mines, a now defunct agency. 相似文献
19.
Concurrent surface- and edge-flaw populations are often observed in strength testing of ceramics The overall strength distribution in such ceramic samples has been analyzed in terms of a modified Weibull distribution function. The junction provides an upper and lower strength limit and is characterized by two shape and location parameters. To evaluate the parameters of the distribution function, the type of flaw that causes failure need not be identified. The applicability of the function has been evaluated in terms of experimental results on SiC specimens. The analysis also shows that the relative values of shape parameters determine which flaw type dominates. 相似文献
20.
A study was done of jute composite using a polymer matrix of epoxidized Novolac resin (ENR), diglycidyl ether of bisphenol A (DGEBA)–based epoxy, and their blends with different weight percentages of the resins. It was found that on blending ENR with DGEBA, the storage modulii at room temperature are enhanced by about 100% or more in the case of 30 and 40% ENR‐containing matrices, whereas the enhancement in the case of 20 and 12% ENR‐containing matrices is only 50% that of the pure matrix. It was also observed that the tan δ peak heights of the composites containing 30 and 40% ENR are closer to that of 20% ENR‐containing composite. The probable explanation drawn on the basis of experimental findings of DMA and mechanical analysis is that by blending ENR with DGEBA epoxy it is possible to manufacture jute composites with increased stiffness without sacrificing their ductility. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2800–2807, 2002 相似文献