全文获取类型
收费全文 | 12935篇 |
免费 | 447篇 |
国内免费 | 58篇 |
专业分类
电工技术 | 268篇 |
综合类 | 16篇 |
化学工业 | 2325篇 |
金属工艺 | 374篇 |
机械仪表 | 361篇 |
建筑科学 | 221篇 |
矿业工程 | 73篇 |
能源动力 | 709篇 |
轻工业 | 1174篇 |
水利工程 | 190篇 |
石油天然气 | 82篇 |
无线电 | 1640篇 |
一般工业技术 | 2822篇 |
冶金工业 | 1559篇 |
原子能技术 | 201篇 |
自动化技术 | 1425篇 |
出版年
2024年 | 41篇 |
2023年 | 183篇 |
2022年 | 511篇 |
2021年 | 520篇 |
2020年 | 418篇 |
2019年 | 413篇 |
2018年 | 571篇 |
2017年 | 522篇 |
2016年 | 492篇 |
2015年 | 284篇 |
2014年 | 453篇 |
2013年 | 891篇 |
2012年 | 529篇 |
2011年 | 683篇 |
2010年 | 548篇 |
2009年 | 543篇 |
2008年 | 485篇 |
2007年 | 394篇 |
2006年 | 342篇 |
2005年 | 267篇 |
2004年 | 246篇 |
2003年 | 221篇 |
2002年 | 181篇 |
2001年 | 146篇 |
2000年 | 150篇 |
1999年 | 156篇 |
1998年 | 357篇 |
1997年 | 231篇 |
1996年 | 252篇 |
1995年 | 219篇 |
1994年 | 182篇 |
1993年 | 172篇 |
1992年 | 143篇 |
1991年 | 152篇 |
1990年 | 114篇 |
1989年 | 108篇 |
1988年 | 130篇 |
1987年 | 110篇 |
1986年 | 89篇 |
1985年 | 115篇 |
1984年 | 94篇 |
1983年 | 107篇 |
1982年 | 99篇 |
1981年 | 88篇 |
1980年 | 78篇 |
1979年 | 54篇 |
1978年 | 46篇 |
1977年 | 56篇 |
1976年 | 76篇 |
1975年 | 32篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Multimedia Tools and Applications - In the way of communication, facial expression act as non-verbal communication and play an important role in social interaction by providing some contextual... 相似文献
22.
Avtar Singh Soottawat Benjakul Nurul Huda 《International Journal of Food Science & Technology》2020,55(12):3553-3562
Effect of debittered salmon frame hydrolysate (DSFH) at various levels (0, 5, 10, 15, 20 and 25 g/100 g) on physicochemical, textural, sensory and nutritional properties of biscuits was investigated. The highest thickness was obtained for the sample with 25 g/100 g DSFH (P < 0.05). There was no difference in diameter among all the biscuit samples (P > 0.05). The samples added with DSFH had lower weight, water activity and moisture content than the control (CONT, without DSFH) (P < 0.05). DSFH at 15 g/100 g showed no detrimental effect on sensory properties of resulting biscuits (DSFH-15). The DSFH-15 biscuit showed reduction in cutting force and fracturability. Scanning electron microscopic and cross-sectional images showed that DSFH-15 biscuit had more porous structure, compared to the CONT. The biscuits fortified with 15 g/100 g DSFH had higher protein but had lower energy value, fat and carbohydrate content than the CONT. 相似文献
23.
Sharma Rachit Kumar Sarkar Prabir Singh Harpreet 《Clean Technologies and Environmental Policy》2020,22(6):1269-1284
Clean Technologies and Environmental Policy - Manufacturing organizations are under continuous pressure to implement sustainability in their activities. There is a need to identify the... 相似文献
24.
Navab SinghAuthor Vitae Moitreyee Mukherjee-RoyAuthor VitaeSohan Singh MehtaAuthor Vitae 《Microelectronics Journal》2003,34(4):237-245
The patterning of contact holes by selecting out-of-focus image plane (defocus) using attenuated phase shift masks (APSM) has been studied. Defocus is found to enhance the image modulation at low partial coherence for contact holes with negative local average of mask function. Semi-dense holes up to 130 nm in 8% APSM have been printed by 0.5 μm defocus at a partial coherence of 0.31 using KrF scanner with highest numerical aperture of 0.68. However, these holes were closed with in-focus imaging. Defocus is also found to be beneficial for patterning the pitches that have extensive side lobes with in-focus imaging. 相似文献
25.
The nature of pairing mechanism as well as transition temperature of yttrium cuprates is discussed using the strong coupling
theory. An interaction potential has been developed for the layered structure with two conducting CuO2(a–b) layers in a unit cell. The interaction potential properly takes care of electron-electron, electron-phonon and electron-plasmon
interactions. Furthermore, the electron-phonon coupling parameter (λ), the modified Coulomb repulsive parameter (μ*) and the 2D acoustic phonon (plasmon) energy as a function of oxygen deficiency is worked out. Finally, the superconducting
transition temperature (T
c) is then evaluated by using these coupling parameters and obtainedT
c = 95(92)K for Y(Yb)Ba2Cu3O7−δ
superconductors withδ = 0·0. The model parameters estimated from the layered structure approach are consistent with the strong coupling theory.
The result deduced on the variation ofT
c withδ are in fair agreement with the earlier reported data on yttrium cuprates. The analysis of the above results are discussed. 相似文献
26.
27.
The electrochemical and corrosion behaviour of a nickel base super alloy (C-263) has been investigated in the deaerated binary and ternary solution mixture of concentrated phosphoric acid, acetic acid, sulphuric acid, nitric acid or water using potentiostatic technique at 35°C. The possibilities of electropolishing of this alloy in these solution mixtures have been also explored. The alloy showed distinct active, passive and transpassive behaviour in the experimental solutions. The alloy remained active and turned passive in the negative potential region. Transpassive dissolution of the alloy is observed and electropolishing is achieved in this region. The best electropolishing is obtained in 50% H3PO4 + 40% CH3COOH + 10% H2SO4. Higher content of water in the electrolytic solution is not useful for electropolishing of the alloy The experimental results also suggest that a current plateau in the transpassive potential region is not a sufficient condition to achieve electropolishing. 相似文献
28.
The physicochemical and functional properties of convection oven- and freeze-dried gluten meals of two corn varieties were evaluated. The physicochemical properties (water solubility index, water absorption index, Hunter color parameters, and bulk density) and functional properties (water absorption, oil absorption, least gelation concentration, protein solubility, and emulsification properties) of convection-oven and freeze-dried corn gluten meals were compared with each other and soy flour. Freeze-dried corn gluten meals was observed to have lower bulk density (0.244-0.263 kg/m3) and was lighter in color (high L and ΔE) compared to their counterpart convection oven-dried gluten meals. Freeze-dried gluten meals from both corn varieties showed significantly higher oil absorption, water absorption, pH, emulsification, and protein solubility compared to oven-dried corn gluten meals. The gluten meals from both corn varieties had lower water absorption and bulk density but higher oil absorption than soy flour, suggesting the hydrophobic nature of corn proteins. Corn gluten meals formed thin (pourable) emulsions compared to soy flour emulsions, which were thick salad dressing type. Freeze- and convection oven-dried corn gluten meals showed significantly lower protein solubility measured at different pH than soy flour. 相似文献
29.
Dielectric relaxation behaviour of (1 − x)PMN − xPZ, for x = 0.10, 0.30 and 0.40 have been studied. The nature of relaxational behaviour was found to change with PZ concentration.
A crossover from a static freezing to critical slowing down like behaviour is observed with increase in Zr4+ concentration. We have used Glazounov and Tangastev criterion to distinguish freezing and critical slowing down like behaviour. 相似文献
30.