全文获取类型
收费全文 | 1630篇 |
免费 | 74篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 375篇 |
金属工艺 | 12篇 |
机械仪表 | 26篇 |
建筑科学 | 44篇 |
矿业工程 | 4篇 |
能源动力 | 47篇 |
轻工业 | 223篇 |
水利工程 | 7篇 |
石油天然气 | 1篇 |
无线电 | 105篇 |
一般工业技术 | 260篇 |
冶金工业 | 359篇 |
原子能技术 | 4篇 |
自动化技术 | 229篇 |
出版年
2023年 | 9篇 |
2022年 | 37篇 |
2021年 | 50篇 |
2020年 | 32篇 |
2019年 | 33篇 |
2018年 | 33篇 |
2017年 | 44篇 |
2016年 | 33篇 |
2015年 | 28篇 |
2014年 | 54篇 |
2013年 | 90篇 |
2012年 | 62篇 |
2011年 | 82篇 |
2010年 | 72篇 |
2009年 | 71篇 |
2008年 | 69篇 |
2007年 | 56篇 |
2006年 | 60篇 |
2005年 | 38篇 |
2004年 | 48篇 |
2003年 | 42篇 |
2002年 | 33篇 |
2001年 | 28篇 |
2000年 | 19篇 |
1999年 | 39篇 |
1998年 | 121篇 |
1997年 | 75篇 |
1996年 | 45篇 |
1995年 | 38篇 |
1994年 | 35篇 |
1993年 | 32篇 |
1992年 | 11篇 |
1991年 | 12篇 |
1990年 | 9篇 |
1989年 | 13篇 |
1988年 | 16篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 10篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 14篇 |
1976年 | 14篇 |
1974年 | 9篇 |
1973年 | 5篇 |
排序方式: 共有1705条查询结果,搜索用时 31 毫秒
41.
Ferry Dharmawan Rodney S. Thomson Henry Li Israel Herszberg Evan Gellert 《Composite Structures》2004,66(1-4):181-187
The structural integrity and damage tolerance of typical composite T-joints found in ships constructed from glass fibre reinforced plastic was the subject of this investigation. The effect of the geometry of the T-joint on the strain distribution was investigated using finite element (FE) analysis. The results, reported in this paper, showed that the critical strains were significantly affected by the joint geometry. Results of the FE analysis conducted to investigate the effect of disbonds between the filler and overlaminate are also reported. This showed that particular defects led to large changes in the strains in the T-joint structure, which would encourage disbond progression. The FE model was validated by mechanical tests on a representative T-joint, instrumented with surface strain gauges and displacement transducers, into which a range of defects was progressively introduced. 相似文献
42.
Angélica R. Jiménez‐Sánchez Israel Santillán Juvenal Rodriguez Resendiz Carlos A. Gonzalez‐Gutierrez Jorge D. Mendiola‐Santibañez 《International journal of imaging systems and technology》2012,22(2):137-144
In this article, a morphological contrast index based on the Weber's law is proposed to quantify the contrast in a processed image. This measure involves the contours of the image along with its background. The proposal made here is applied to detect the image with higher contrast, and also identify the enhanced image most similar to the original. Moreover, the contrast index is compared with other four indexes reported in the current literature. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 137–144, 2012 相似文献
43.
M. Morales M.E. Navarro X.G. Capdevila J.J. Roa M. Segarra 《Ceramics International》2012,38(5):3713-3722
A simple gel-casting method was successfully combined with the spray-coating technique to manufacture graded anode-supported micro-tubular solid oxide fuel cells (MT-SOFCs) based on samaria-doped ceria (SDC) as an electrolyte. Micro-tubular anodes were shaped by a gel-casting method based on a new and simple forming technique that operates as a syringe. The aqueous slurry formulation of the NiO–SDC substrate using agarose as a gelling agent, and the effect of spray-coating parameters used to deposit the anode functional layers (AFLs) and electrolyte were investigated. Furthermore, pre-sintering temperature of anode substrates was systematically studied to avoid the anode–electrolyte delamination and obtain a dense electrolyte without cracks, after co-sintering process at 1450 °C. Despite the high shrinkage of substrate (~70%), an anode porosity of ~37% was achieved. MT-SOFCs with ~2.5 mm of outer diameter, 370 μm thick substrate, 20 μm thick AFLs and 15 μm thick electrolyte were successfully obtained. The use of AFLs with 30:70 and 50:50 wt% NiO–SDC allowed to obtain a continuous gradation of composition and porosity in the anode–electrolyte interface. 相似文献
44.
Israel Spiegler 《Information Systems Management》2013,30(2):7-14
Data bases are the heart of any information system, and yet they cannot always support the varied managerial demands imposed on them. One reason is that designers and users view data differently. This article describes leading-edge thinking about data base design, including research into the use of neural networks for data storage 相似文献
45.
Christina M. Rudin-Brown Michael G. LennéJessica Edquist Jordan Navarro 《Accident; analysis and prevention》2012
Although collisions at level crossings are relatively uncommon occurrences, the potential severity of their consequences make them a top priority among safety authorities. Twenty-five fully-licensed drivers aged between 20 and 50 years participated in a driving simulator study that compared the efficacy, and drivers’ subjective perception, of two active level crossing traffic control devices: flashing lights with boom barriers and standard traffic lights. Because of its common usage in most states in Australia, a stop sign-controlled level crossing served as the passive referent. Although crossing violations were less likely at the level crossings controlled by active devices than at those controlled by stop signs, both kinds of active control were associated with a similar number of violations. Further, the majority (72%) of drivers reported preferring flashing lights to traffic lights. Collectively, results indicate that the installation of traffic lights at real-world level crossings would not be likely to offer safety benefits over and above those provided already by flashing lights with boom barriers. Furthermore, the high rate of violations at passively controlled crossings strongly supports the continued practice of upgrading level crossings with active traffic control devices. 相似文献
46.
Structural design of carbon/epoxy bio‐inspired wind turbine blade using fluid/structure simulation 下载免费PDF全文
Mariana Correa‐Álvarez Valentina Villada‐Quiceno Julián Sierra‐Pérez Juan Guillermo García‐Navarro César Nieto‐Londoño 《国际能源研究杂志》2016,40(13):1832-1845
The purpose of this paper is to present the structural design procedure of a low‐speed, horizontal axis, bio‐inspired wind turbine blade made of carbon/epoxy. The methodology initiates with the mechanical characterization of the carbon fiber composite material. An aerodynamic simulation using Computational Fluid Dynamics (CFD) method is performed in order to obtain the pressure distribution profile of the blade. This result is coupled with a Finite Element Analysis (FEA) to carry out an iterative design process through a Fluid‐Structure Interaction (FSI) simulation. Different stacking sequences of laminates are evaluated to find a configuration which allows balance between aerodynamic and dynamic inertial loads, ensuring an almost undeformed geometry during wind turbine's operation. The final structural design of the blade consists in six regions with different laminates. These are balanced and symmetric with distinct thickness characteristics and stacking sequences, which vary in three different orientations: 0°, ± 45° and 90°, achieving a minimum deflection at the tip close to 3.11 cm, and a total weight of 3.6 kg of a 1.8 m radius blade, even with the restrictions imposed by the non‐conventional geometry. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
47.
Andrea Ruiu Mireille Vonlanthen Pasquale Porcu Israel Gonzalez-Méndez Ernesto Rivera 《Journal of Inorganic and Organometallic Polymers and Materials》2018,28(2):448-456
In this paper, we describe the synthesis and characterization of four novel pyrene labeled compounds, some of them dendritic, which can act as potential sensors for the detection of nitro compounds in methanol solution. Methanol was selected as solvent due to its polar properties, which provide similar characteristics to water. The obtained pyrene labeled molecules (PyOH, Pytb, PyNK1OH and PyNK1tb) were studied by UV–Vis and steady state fluorescence spectroscopy. Their application as sensors has been tested with three different nitro compounds: nitrobenzene, 1-chloro-2,4-dinitrobenzene and nitromethane. PyOH and Pytb showed a detection concentration limit for the analyzed quenchers in the order of nM, making these compounds suitable for high-sensitive sensoring. PyNK1OH and PyNK1tb displayed high sensibility at µM concentration. All the sensors showed an accurate response towards quencher analytes. 相似文献
48.
Israel I. Zetina-Rios Gloria-L. Osorio-Gordillo Rodolfo A. Vargas-Méndez Guadalupe Madrigal-Espinosa Carlos-M. Astorga-Zaragoza 《International Journal of Adaptive Control and Signal Processing》2021,35(5):828-845
This article presents a generalized learning observer (GLO) design for the simultaneous estimation of states and actuator faults for polytopic quasi-linear parameter varying systems. The proposed approach is based on the use of a GLO, which generalized the existing results on the proportional-integral observers. Conditions of existence and stability of the observer are given through the stability analysis in the sense of Lyapunov. Its design is obtained in terms of a set of linear matrix inequalities. The performance of the proposed method is evaluated by simulation in a one-link-flexible joint robot system. 相似文献
49.
50.
Ricardo Colomo-Palacios Israel González-Carrasco Jose Luis López-Cuadrado Antonio Trigo Joao Eduardo Varajao 《Information Systems Frontiers》2014,16(4):607-625
People in software development teams are crucial in order to gain and retain strategic advantage inside a highly competitive market. As a result, human factors have gained attention in the software industry. Software Project Managers are decisive to achieve project success. A competent project manager is capable of solving any problem that an organization may encounter, regardless of its complexity. This paper presents I-Competere which is a tool developed to forecast competence gaps in key management personnel by predicting planning and scheduling competence levels. Based on applied intelligence techniques, I-Competere allows the forecast and anticipation of competence needs thus articulating personnel development tools and techniques. The results of the test, using several artificial neural networks, are more than promising and show prediction accuracy. 相似文献