全文获取类型
收费全文 | 5222篇 |
免费 | 95篇 |
国内免费 | 15篇 |
专业分类
电工技术 | 86篇 |
综合类 | 8篇 |
化学工业 | 996篇 |
金属工艺 | 152篇 |
机械仪表 | 153篇 |
建筑科学 | 118篇 |
矿业工程 | 5篇 |
能源动力 | 375篇 |
轻工业 | 445篇 |
水利工程 | 63篇 |
石油天然气 | 75篇 |
武器工业 | 2篇 |
无线电 | 565篇 |
一般工业技术 | 1122篇 |
冶金工业 | 618篇 |
原子能技术 | 51篇 |
自动化技术 | 498篇 |
出版年
2024年 | 86篇 |
2023年 | 105篇 |
2022年 | 157篇 |
2021年 | 201篇 |
2020年 | 206篇 |
2019年 | 176篇 |
2018年 | 231篇 |
2017年 | 196篇 |
2016年 | 194篇 |
2015年 | 118篇 |
2014年 | 181篇 |
2013年 | 371篇 |
2012年 | 199篇 |
2011年 | 253篇 |
2010年 | 177篇 |
2009年 | 186篇 |
2008年 | 184篇 |
2007年 | 131篇 |
2006年 | 124篇 |
2005年 | 84篇 |
2004年 | 71篇 |
2003年 | 72篇 |
2002年 | 60篇 |
2001年 | 50篇 |
2000年 | 55篇 |
1999年 | 63篇 |
1998年 | 185篇 |
1997年 | 121篇 |
1996年 | 99篇 |
1995年 | 78篇 |
1994年 | 70篇 |
1993年 | 62篇 |
1992年 | 51篇 |
1991年 | 47篇 |
1990年 | 39篇 |
1989年 | 49篇 |
1988年 | 39篇 |
1987年 | 34篇 |
1986年 | 41篇 |
1985年 | 52篇 |
1984年 | 37篇 |
1983年 | 47篇 |
1982年 | 50篇 |
1981年 | 45篇 |
1980年 | 44篇 |
1979年 | 36篇 |
1977年 | 32篇 |
1976年 | 39篇 |
1974年 | 21篇 |
1973年 | 20篇 |
排序方式: 共有5332条查询结果,搜索用时 15 毫秒
101.
In this paper, a new and innovative process for assembling chains of carbon nanofibers (CNFs) in epoxy, uniquely different from those generally used for chaining particles in a liquid medium, is presented. Chains of aligned CNFs are assembled in a region rich in CNFs and extended into regions where there are no CNFs. A physical explanation of the process is provided based on the conductive nature of the CNFs. By contacting the chains with the electrodes, the process of chain growth is expedited and well-ordered parallel chains with equal?spacing are grown over distances of 2?cm. 相似文献
102.
V.?K.?SyalEmail author S.?K.?Thakur S.?Chauhan P.?Sharma 《International Journal of Thermophysics》2005,26(3):807-826
Ultrasonic velocities and densities of the drug Parvon-spas in binary mixtures of water with methanol (MeOH), ethanol (EtOH), and propan-1-ol (1-PrOH) have been measured over the complete solvent composition range at 10 mol% intervals at 25°C. Various acoustic parameters such as the acoustic impedance (Z), adiabatic compressibility (β), intermolecular free length (Lf), relative association (R.A.), molar volume (Vm), and molar sound velocity (Rm) have been calculated. In addition, excess functions, i.e., excess adiabatic compressibility (βE), excess intermolecular free length (LfE), excess molar volume (VE), excess ultrasonic velocity (UE), and excess acoustic impedance (ZE) for these three solvent mixtures in the absence and presence of the drug have been calculated. A different behavior of these parameters in these alcohol systems has been discussed in terms of the length of the alcohol molecule, the molecular volume, as well as inter/intramolecular interactions of these molecules. 相似文献
103.
A two region flow model has been developed in this paper in the presence of external magnetic field for the better understanding of synovial joint lubrication mechanism. The model consists of two parallel porous cartilageous surfaces separated by a thin film of non newtonian lubricant representing the synovial fluid which is assumed to behave like a paramagnetic fluid system. In this paper, we have represented the cartilage by a mixture of two interacting continua and synovial fluid by viscoelastic fluid. A transverse magnetic field is applied to the system. We have used the modified form of Darcy’s law given by Zahn and Rosenweig; to describe the penetration dynamics of magnetic fluids through porous media. Because of exact solution not being possible for the governing non-linear partial differential equations, the perturbation method has been used to obtain approximate solutions. The results have been obtained by computational techniques and compared by results available in the literature. In this paper, the possibility of increased efficiency of joint lubrication, particularly in diseased states by the application of applied magnetic fields has been explored. The applied magnetic field increases the load carrying capacity. Which helps in sustaining greater loads. Similarly, the viscoelastic parameter describes the increase in the concentration of the suspended hyaluronic acid molecules which, in turn, increases the overall viscosity of the lubricant, which also helps in sustaining greater loads. 相似文献
104.
105.
Chavan Shankar Dattatray Kulkarni Anju VijayKumar 《Wireless Personal Communications》2019,109(3):1897-1910
Wireless Personal Communications - In the growing world of technology, use of WSN is increasing at an exponential rate in many real time applications such as security, monitoring, tracking,... 相似文献
106.
Wireless Networks - This paper presents a naked mole rat (NMR) inspired energy efficient protocol for heterogeneous wireless sensor network. NMR uses strategic deployment among three types of nodes... 相似文献
107.
Dharmendra Pratap Singh Swadesh Kumar Gupta Satya Prakash Yadav P K Sharma A C Pandey Rajiv Manohar 《Bulletin of Materials Science》2014,37(3):511-518
The present paper deals with the characterization of a ferroelectric liquid crystal–nanoparticle (FLC–NP) composite system. The dielectric, electrical and polarization property of the FLC–NP composite system have been studied as a function of temperature and frequency. Ferroelectric Cu-doped ZnO (Cu–ZnO) nanoparticles have been added to the pure ferroelectric liquid crystal (FLC) Felix 17/100. The nanoparticles are bigger in size as compared to FLC molecules; therefore, they distort the existing geometry of FLC matrix and set up an antiparallel correlation with the dipole moments of the host FLC molecules. This antiparallel correlation of guest–host geometry reduces the net ferroelectricity of the composite system and modifies all the physical properties of the pure FLC. The change in properties has been analysed and explained in the light of guest–host interaction. 相似文献
108.
Potential of Sr4Al14O25: Eu2+,Dy3+ inorganic oxide-based nanophosphor in Latent fingermark detection
Vishal Sharma Amrita Das Vinay Kumar O. M. Ntwaeaborwa H. C. Swart 《Journal of Materials Science》2014,49(5):2225-2234
In this paper, the potential of the Sr4Al14O25: Eu2+,Dy3+ fluorescent nanophosphor is explored to visualize the latent fingermarks. The nanophosphor has been synthesized using self-propagating high temperature synthesis and shows intense luminescence and strong long after glow properties. These nano particles have been characterized for their particle size, crystalline phase, and photoluminescent properties. The calculated PL CIE co-ordinates (0.138, 0.359) correspond to the blue–green shade. Different porous, non-porous, as well as slightly non-smooth surfaces are taken and successfully tested for latent fingerprints development with the prepared Sr4Al14O25: Eu2+,Dy3+ fluorescent nanophosphor powder. Present nano powder is advantageous to use on luminescent or multicolored surfaces as it gives greater contrast and also eliminates the problem of background interferences with the friction ridges due to its strong long after glow property. The results are very good when latent fingerprints were developed on the currency notes with optical variable ink and highly fluorescent pattern areas. 相似文献
109.
110.