全文获取类型
收费全文 | 1229篇 |
免费 | 84篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 9篇 |
综合类 | 1篇 |
化学工业 | 270篇 |
金属工艺 | 20篇 |
机械仪表 | 45篇 |
建筑科学 | 61篇 |
矿业工程 | 3篇 |
能源动力 | 93篇 |
轻工业 | 120篇 |
水利工程 | 15篇 |
石油天然气 | 5篇 |
无线电 | 112篇 |
一般工业技术 | 218篇 |
冶金工业 | 69篇 |
原子能技术 | 15篇 |
自动化技术 | 259篇 |
出版年
2024年 | 4篇 |
2023年 | 13篇 |
2022年 | 28篇 |
2021年 | 38篇 |
2020年 | 32篇 |
2019年 | 35篇 |
2018年 | 63篇 |
2017年 | 36篇 |
2016年 | 65篇 |
2015年 | 37篇 |
2014年 | 63篇 |
2013年 | 120篇 |
2012年 | 73篇 |
2011年 | 100篇 |
2010年 | 61篇 |
2009年 | 134篇 |
2008年 | 79篇 |
2007年 | 56篇 |
2006年 | 56篇 |
2005年 | 29篇 |
2004年 | 29篇 |
2003年 | 22篇 |
2002年 | 21篇 |
2001年 | 12篇 |
2000年 | 14篇 |
1999年 | 7篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1980年 | 2篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 2篇 |
排序方式: 共有1315条查询结果,搜索用时 15 毫秒
101.
Birten Çakmaklı Baki Hazer Şerefden Açıkgöz Murat Can Füsun B. Cömert 《应用聚合物科学杂志》2007,105(6):3448-3457
Synthesis of Poly(methyl methacrylate), PMMA‐multigraft copolymers derived from linseed oil, soybean oil, and linoleic acid PMMA‐g‐polymeric oil/oily acid‐g‐poly(3‐hydroxy alkanoate) (PHA), and their protein adsorption and bacterial adherence have been described. Polymeric oil/oily acid peroxides [polymeric soybean oil peroxide (PSB), polymeric linseed oil peroxide (PLO), and polymeric linoleic acid peroxide (PLina)] initiated the copolymerization of MMA and unsaturated PHA‐soya to yield PMMA–PLO–PHA, PMMA–PSB–PHA, and PMMA–PLina–PHA multigraft copolymers. PMMA–PLina–PHA multigraft copolymers were completely soluble while PMMA–PSB–PHA and PMMA–PLO–PHA multigraft copolymers were partially crosslinked. Crosslinked parts of the PLO‐ and PSB‐multigraft copolymers were isolated by the sol gel analysis and characterized by swelling measurements in CHCl3. Soluble part of the PLO‐ and PSB‐multigraft copolymers and completely soluble PLina‐multigraft copolymers were obtained and characterized by spectroscopic, thermal, gel permeation chromatography (GPC), and scanning electron microscopy (SEM) techniques. In the mechanical properties of the PHA–PLina–PMMA, the elongation at break is reduced up to ~ 9%, more or less preserving the high stress values at its break point (48%) when compared to PLina‐g‐PMMA. The solvent casting film surfaces were studied by means of adsorption of blood proteins and bacterial adhesion. Insertion of the PHA into the multigraft copolymers caused the dramatic increase in bacterial adhesion on the polymer surfaces. PHA insertion into the graft copolymers also increased the protein adsorption. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
102.
In this article we investigate the impacts of interspacing and source polling policies on the cell‐loss rates in transmission
of variable bit rate video sources over Asynchronous Transfer Mode networks. We present a mathematical model that finds the
approximate optimal starting times of the video sources that minimize the congestion at the multiplexer. Combined with the
approximate optimal source starting times, we propose a source ordering and polling policy for reducing the cell‐loss rates.
The proposed policy is tested against alternative policies using simulation of pre‐recorded video data.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
103.
A variety of iron-metallated functional porphyrins have been synthesized and their catalytic activity to oxidize polycyclic aromatic hydrocarbons, (PAHs) using hydrogen peroxide as oxidant was investigated. It was found that iron-metallated porphyrins bearing strong electronegative groups at β-pyrrolic positions show an exceptionally high catalytic efficiency. 相似文献
104.
Solution of linear systems in arterial fluid mechanics computations with boundary layer mesh refinement 总被引:1,自引:1,他引:0
Murat Manguoglu Kenji Takizawa Ahmed H. Sameh Tayfun E. Tezduyar 《Computational Mechanics》2010,46(1):83-89
Computation of incompressible flows in arterial fluid mechanics, especially because it involves fluid–structure interaction,
poses significant numerical challenges. Iterative solution of the fluid mechanics part of the equation systems involved is
one of those challenges, and we address that in this paper, with the added complication of having boundary layer mesh refinement
with thin layers of elements near the arterial wall. As test case, we use matrix data from stabilized finite element computation
of a bifurcating middle cerebral artery segment with aneurysm. It is well known that solving linear systems that arise in
incompressible flow computations consume most of the time required by such simulations. For solving these large sparse nonsymmetric
systems, we present effective preconditioning techniques appropriate for different stages of the computation over a cardiac
cycle. 相似文献
105.
Ozan Gürbüz Duygu Göçmen Fatih Dagˇdelen Murat Gürsoy Sami Aydin İsmet Şahin Levent Büyükuysal Mehmet Usta 《Food chemistry》2007,100(2):518-525
Concentrations of trans-resveratrol, catechin and epicatechin were analyzed in musts and wines produced from seven red and four white grape cultivars from various wine growing regions of Turkey. Phenolics were quantified using an HPLC method optimized for the separation of wine phenolics. Wine samples contained higher phenolics levels than the corresponding musts. With the exception of Semillion, white wines and musts contained lower concentrations of phenolics than red wines and musts. However, the white cultivar Semillion had the highest concentrations of catechin and epicatechin among all wine and must samples. Semillion wine catechin and epicatechin were 13.7 and 11.8 mg/L, respectively. The highest level of trans-resveratrol among the white cultivars was found in Narince wine (1.93 mg/L). Within the red wine and must cultivars, Bo?azkere, Öküzgozü, and Cabernet contained the highest concentrations of flavan-3-ols and trans-resveratrol. Catechin was the major phenolic in all wines and most musts. Epicatechin was the major phenolic in 6 of the 11 must samples, but none of the wine samples. trans-Resveratrol was generally found in lowest concentrations in both wines and musts. 相似文献
106.
107.
Environmental concerns and limited resource of petroleum fuels have caused interests in the development of alternative fuels for internal combustion (IC) engines. For diesel engines, alcohols are receiving increasing attention because they are oxygenated and renewable fuels. Therefore, in this study, the effect of injection timing on the exhaust emissions of a single cylinder, naturally aspirated, four-stroke, direct injection diesel engine has been experimentally investigated by using methanol-blended diesel fuel from 0% to 15% with an increment of 5%. The tests were conducted for three different injection timings (15°, 20° and 25 °CA BTDC) at four different engine loads (5 Nm, 10 Nm, 15 Nm, 20 Nm) at 2200 rpm. The experimental test results showed that Bsfc, NOx and CO2 emissions increased as BTE, smoke opacity, CO and UHC emissions decreased with increasing amount of methanol in the fuel mixture. When compared the results to those of original injection timing, NOx and CO2 emissions decreased, smoke opacity, UHC and CO emissions increased for the retarded injection timing (15 °CA BTDC). On the other hand, with the advanced injection timing (25 °CA BTDC), decreasing smoke opacity, UHC and CO emissions diminished, and NOx and CO2 emissions boosted at all test conditions. In terms of Bsfc and BTE, retarded and advanced injection timings gave negative results for all fuel blends in all engine loads. 相似文献
108.
109.
Murat Manguoglu Ahmed H. Sameh Tayfun E. Tezduyar Sunil Sathe 《Computational Mechanics》2008,43(1):73-80
We present an effective preconditioning technique for solving the nonsymmetric linear systems encountered in computation of
incompressible flows in long domains. The application category we focus on is arterial fluid mechanics. These linear systems
are solved using a nested iterative scheme with an outer Richardson scheme and an inner iteration that is handled via a Krylov
subspace method. Test computations that demonstrate the robustness of our nested scheme are presented. 相似文献
110.
Optimal Distributed Location Management in Mobile Networks 总被引:4,自引:0,他引:4
Krishnamurthi Govind Azizoğlu Murat Somani Arun K. 《Mobile Networks and Applications》2001,6(2):117-124
An important issue in the design of future Personal Communication Services (PCS) networks is the efficient management of location information. In this paper, we consider a distributed database architecture for location management in which update and query loads of the individual databases are balanced. We obtain lower bounds to the worst-case delay in locating a mobile user, to the average delay, and to the call blocking probability. We then propose a dynamic location management algorithm that meets these lower bounds. The optimality of this algorithm with respect to these three performance measures, as well as simplicity, make it an appealing candidate for distributed location management in PCS networks. 相似文献