全文获取类型
收费全文 | 651篇 |
免费 | 39篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 169篇 |
金属工艺 | 14篇 |
机械仪表 | 22篇 |
建筑科学 | 15篇 |
矿业工程 | 1篇 |
能源动力 | 26篇 |
轻工业 | 66篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 61篇 |
一般工业技术 | 117篇 |
冶金工业 | 47篇 |
原子能技术 | 5篇 |
自动化技术 | 137篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 39篇 |
2021年 | 42篇 |
2020年 | 36篇 |
2019年 | 40篇 |
2018年 | 43篇 |
2017年 | 30篇 |
2016年 | 33篇 |
2015年 | 34篇 |
2014年 | 38篇 |
2013年 | 50篇 |
2012年 | 29篇 |
2011年 | 35篇 |
2010年 | 25篇 |
2009年 | 25篇 |
2008年 | 14篇 |
2007年 | 19篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 14篇 |
2003年 | 10篇 |
2002年 | 16篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 7篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有690条查询结果,搜索用时 15 毫秒
61.
62.
Polymer electrolyte membrane fuel cells (PEMFCs) show great promise in portable, automotive, and stationary applications. They have reached the test and demonstration phase in automotive and power markets today. This paper is focused on a stand-alone residential PEMFC power system that provides the electricity needs of the house. A novel stochastic sizing methodology is developed that considers both fuel cell system dynamics and residential load dynamics in overall system sizing for the stand-alone residential fuel cell power system. Understanding the nature of demand side is critical in stand-alone system sizing. Thus, experimental measurements have been completed to capture the load side dynamics in detail. No such data is found in the current literature. The Threshold Bootstrap method is used to model the residential load demand and to produce many realistic load profiles. Matlab/Simulink is used to run system simulations to determine system sizes based on parameters defined through a designed experiment. Comparison between the proposed sizing method and a possible worst case scenario sizing is given. The new sizing methodology can be used together with sophisticated demand analysis programs to obtain customized sizing for each user as stand-alone power systems become more viable. 相似文献
63.
In this study, the bubble point pressure effect or, as it is more commonly known, the flashing point effect of CO2 on geothermal fluids is shown, and the compressibility of the geothermal fluids containing low concentrations of dissolved CO2 at the flashing point is formulated for isoenthalpic phase change. The compressibility, termed the isoenthalpic flashing point compressibility, can be calculated with well-known parameters. New, easy-to-use graphs are presented to estimate the compressibility for such systems. Correction for ionic strength of the geothermal brine is also considered. The practical use of the compressibility is illustrated to estimate the fluid content of a geothermal reservoir. A material balance method incorporating the isoenthalpic flashing point compressibility in geothermal modeling is investigated. The material balance method presented in the paper is of primary importance in the evaluation of geothermal reservoirs since both the areal extent and the vertical thickness can not be accurately determined, particularly in the initial development stages of the reservoirs. Applications of the method to geothermal fields are discussed. 相似文献
64.
Textile composite double dome stamping simulation using a non-orthogonal constitutive model 总被引:1,自引:0,他引:1
Stamping is one of the most effective ways to form textile composites in industry for providing high-strength, low-weight and cost-effective products. This paper presents a fully continuum mechanics-based approach for stamping simulation of textile fiber reinforced composites by using finite element (FE) method. A previously developed non-orthogonal constitutive model is used to represent the anisotropic mechanical behavior of textile composites under large deformation during stamping. Simulation are performed on a balanced plain weave composite with 0°/90° and ±45° as initial yarn orientation over a benchmark double dome device. Simulation results show good agreement with experimental output in terms of a number of parameters selected for comparison. The effects of meshing and shear moduli obtained from bias extension test and picture frame test on forming simulation results are also investigated. 相似文献
65.
M. H. Aslan A. Y. Oral E. Men
ur A. Gül E. Ba
aran 《Solar Energy Materials & Solar Cells》2004,82(4):6554
c-axis-oriented zinc-oxide (ZnO) thin films were prepared on microscope glass substrates by sol–gel deposition. A homogeneous and stable solution was prepared by dissolving zinc-acetate 2-hydrate (ZnAc) in 2-propanol and diethanolamine. Crystalline ZnO thin films were obtained following an annealing process at temperatures between 450°C and 550°C for 1 h. Increasing annealing temperature increased the grain size and the c-axis orientation. The X-ray diffraction analysis revealed single-phase ZnO with hexagonal zincite structure. The absorption edge analysis revealed that the optical band-gap energy for the films were between 3.26 and 3.28 eV and electronic transition was direct transition type. 相似文献
66.
In this paper, several simple and efficient sign based normalized adaptive filters, which are computationally superior having multiplier free weight update loops are used for cancelation of noise in electrocardiographic (ECG) signals. The proposed implementation is suitable for applications such as biotelemetry, where large signal to noise ratios with less computational complexity are required. These schemes mostly employ simple addition, shift operations and achieve considerable speed up over the other least mean square (LMS) based realizations. Simulation studies shows that the proposed realization gives better performance compared to existing realizations in terms of signal to noise ratio and computational complexity. 相似文献
67.
Ajay Matta Muhammad Zia Karim Hoda Gerami Bettina Zoe Benigno Ivan Cheng Arne Mehrkens William Mark Erwin 《International journal of molecular sciences》2022,23(10)
Background: Tissue sources of pain emanating from degenerative discs remains incompletely understood. Canine intervertebral discs (IVDs) were needle puncture injured, 4-weeks later injected with either phosphate-buffered saline (PBS) or NTG-101, harvested after an additional fourteen weeks and then histologically evaluated for the expression of NGFr, BDNF, TrkB and CALCRL proteins. Quantification was performed using the HALO automated cell-counting scoring platform. Immunohistochemical analysis was also performed on human IVD tissue samples obtained from spinal surgery. Immunohistochemical analysis and quantification of neurotrophins and neuropeptides was performed using an in vivo canine model of degenerative disc disease and human degenerative disc tissue sections. Discs injected with NTG-101 showed significantly lower levels of Nerve Growth Factor receptor (NGFr/TrkA, p = 0.0001), BDNF (p = 0.009), TrkB (p = 0.002) and CALCRL (p = 0.008) relative to PBS injections. Human IVD tissue obtained from spinal surgery due to painful DDD show robust expression of NGFr, BDNF, TrkB and CALCRL proteins. A single intradiscal injection of NTG-101 significantly inhibits the expression of NGFr, BDNF, TrkB and CALCRL proteins in degenerative canine IVDs. These results strongly suggest that NTG-101 inhibits the development of neurotrophins that are strongly associated with painful degenerative disc disease and may have profound effects upon the management of patients living with discogenic pain. 相似文献
68.
69.
Opar Ekin Alpakut Gizem Parlatan Uğur Yavaş Seydi Yüksel Bahar Ünlü M. Burçin Buyru H. Faruk Baştu Ercan Ferhanoğlu Onur 《Instruments and Experimental Techniques》2022,65(3):444-451
Instruments and Experimental Techniques - With its elongated depth of focus, Bessel beams offer rapid and high aspect ratio ablation capability, in contrast to Gaussian beam counterparts. In this... 相似文献
70.
Živec Tina Anžur Andreja Verbovšek Timotej 《Bulletin of Engineering Geology and the Environment》2019,78(3):1631-1643
Bulletin of Engineering Geology and the Environment - Terrestrial laser scanning (TLS) was performed in tectonically undisturbed flysch in the Elerji quarry (south-west Slovenia), which represents... 相似文献