全文获取类型
收费全文 | 35059篇 |
免费 | 2336篇 |
国内免费 | 991篇 |
专业分类
电工技术 | 1482篇 |
技术理论 | 4篇 |
综合类 | 1553篇 |
化学工业 | 6073篇 |
金属工艺 | 1536篇 |
机械仪表 | 1669篇 |
建筑科学 | 1688篇 |
矿业工程 | 758篇 |
能源动力 | 1194篇 |
轻工业 | 2227篇 |
水利工程 | 448篇 |
石油天然气 | 1010篇 |
武器工业 | 146篇 |
无线电 | 5406篇 |
一般工业技术 | 5073篇 |
冶金工业 | 2736篇 |
原子能技术 | 388篇 |
自动化技术 | 4995篇 |
出版年
2024年 | 105篇 |
2023年 | 449篇 |
2022年 | 863篇 |
2021年 | 1197篇 |
2020年 | 927篇 |
2019年 | 800篇 |
2018年 | 898篇 |
2017年 | 945篇 |
2016年 | 861篇 |
2015年 | 1069篇 |
2014年 | 1413篇 |
2013年 | 2116篇 |
2012年 | 1986篇 |
2011年 | 2308篇 |
2010年 | 1832篇 |
2009年 | 1878篇 |
2008年 | 1929篇 |
2007年 | 1739篇 |
2006年 | 1566篇 |
2005年 | 1254篇 |
2004年 | 1107篇 |
2003年 | 1190篇 |
2002年 | 1397篇 |
2001年 | 1177篇 |
2000年 | 816篇 |
1999年 | 709篇 |
1998年 | 977篇 |
1997年 | 690篇 |
1996年 | 577篇 |
1995年 | 474篇 |
1994年 | 388篇 |
1993年 | 332篇 |
1992年 | 247篇 |
1991年 | 221篇 |
1990年 | 225篇 |
1989年 | 199篇 |
1988年 | 170篇 |
1987年 | 153篇 |
1986年 | 129篇 |
1985年 | 127篇 |
1984年 | 110篇 |
1983年 | 75篇 |
1982年 | 70篇 |
1981年 | 59篇 |
1980年 | 81篇 |
1979年 | 49篇 |
1978年 | 60篇 |
1977年 | 58篇 |
1976年 | 76篇 |
1975年 | 43篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
In this paper, a representative unit volume finite element (RUV FE) model was employed to simulate thermoforming process of carbon fabric-polymeric foam sandwich structures. Thermoforming simulations, which capture crimp angles and amplitude changes of carbon fabric with respect to different operational pressure, were conducted with the help of RUV FE model. Micro-deformation of tow structures after thermoforming was rigorously reflected in the second stage FE model to determine the in-plane directional stiffness of skin parts. Tensile tests were carried out to investigate mechanical properties of skin parts in sandwich structures for the potential usage of automotives, electronic housings or the satellite structure design. 相似文献
122.
Wang J.-H. Chang F.-C. Su F.-W. 《Vision, Image and Signal Processing, IEE Proceedings -》2006,153(5):657-665
A method called self-organising fusion (SOF) for performing fast image segmentation is presented. The input image is divided into a set of small regions, each associated with a working feature. First, all regions are simultaneously updated and then a statistical process is applied to merge the qualified regions. The contours of objects are obtained by alternating the two processes of updating and merging until convergence. The concurrent updating creates a SOF behaviour that facilitates the identification of regions presumably comprising the same object. The method can save computation cost as both updating and merging are conducted in parallel fashion, and as parameter selection is done for local regions, it is able to deal with fairly complex images 相似文献
123.
本文介绍了安钢100吨电炉两级自动控制系统的设计方案,详细阐述了一级、二级自动控制系统的配置和功能,对于系统运行中出现的问题,提出了改进方案。 相似文献
124.
Dynamic deformation behavior of ultrafine-grained low-carbon steels fabricated by equal-channel angular pressing 总被引:1,自引:0,他引:1
Byoungchul Hwang Yang Gon Kim Han Sang Lee Sunghak Lee Byoung Doo Ahn Dong Hyuk Shin Chang Gil Lee 《Metallurgical and Materials Transactions A》2005,36(2):389-397
The dynamic deformation behavior of ultrafine-grained low-carbon steels fabricated by equal-channel angular pressing (ECAP)
was investigated in this study. Dynamic torsional tests, using a torsional Kolsky bar, were conducted on four steel specimens,
two of which were annealed at 480 °C after ECAP, and then the test data were compared in terms of microstructures, tensile
properties, and adiabatic shear-band formation. The equal-channel angular pressed specimen consisted of very fine, equiaxed
grains of 0.2 to 0.3 μm in size, which were slightly coarsened after annealing. The dynamic torsional test results indicated that maximum shear
stress decreased with increasing annealing time, whereas fracture shear strain increased. Some adiabatic shear bands were
observed at the gage center of the dynamically deformed torsional specimen. Their width was smaller in the equal-channel angular
pressed specimen than in the 1-hour-annealed specimen, but they were not found in the 24-hour-annealed specimen. Ultrafine,
equiaxed grains of 0.05 to 0.2 μm in size were formed inside the adiabatic shear band, and their boundaries had characteristics of high-angle grain boundaries.
These phenomena were explained by dynamic recrystallization due to a highly localized plastic strain and temperature rise
during dynamic deformation. 相似文献
125.
126.
Chia-Hui Chang Harianto Siek Jiann-Jyh Lu Chun-Nan Hsu Jen-Jie Chiou 《Intelligent Systems, IEEE》2003,18(5):34-40
Web wrapper agents exploit online Web data sources, facilitating information integration and reuse. With the DeepSpot Agent Toolbox, users can automate virtually all types of Web browsing sessions simply by browsing the target Web sites. 相似文献
127.
Hsin-Lu Chang Robert F. Easley Michael J. Shaw 《Information Systems and E-Business Management》2003,1(2):213-228
This research seeks to provide an economic framework for understanding two major forms of e-marketplaces: aggregation-oriented
vs. exchange-oriented e-marketplaces. By analyzing the marginal benefit per transaction in alternative models, we are able
to determine the most suitable B2B e-marketplace for a wide variety of product categories, market conditions, and procurement
methods. For example, when companies sell commodities in a fragmented market, the aggregation model is suitable for spot purchasing,
and the exchange model works best for systematic purchasing. In addition, the effect of supplier consolidation and information
technology-enabled cost reduction on model selection is discussed. 相似文献
128.
常卫东 《河北建筑工程学院学报》2003,21(2):80-82
通过对独立方案在有限资金的约束下,进行方案组合比选的两种方法进行讨论,使两种方法结合在一起形成一种新的比选方法. 相似文献
129.
以油料在管道中输送为例进行电容层析成象仿真.利用有限元方法对电场建立数学模型,在SGI indigo 2
工作站上,使用AVS可视化软件和反投影算法,对3种典型流态模型反演及显示其流体成份分布的图象. 相似文献
130.
焦化废水中多组分酚的因子分析—岭回归-光度法同时测定 总被引:2,自引:0,他引:2
根据3-甲基-2-苯并噻唑腙(MBTH)与酚类发生偶合显色反应而生成有不同颜色的稳定配合物的特点,测定废水中酚类混合体系的吸收光谱,结合因子分析和岭回归技术对工业废水中苯酚、邻甲酚、3,4-二甲酚、2,3-二甲酚、邻苯二酚等多组分酚的光谱数据进行解析,成功的确定了废水中酚的物种数,物种种类及各物种含量. 相似文献