全文获取类型
收费全文 | 1524篇 |
免费 | 87篇 |
国内免费 | 30篇 |
专业分类
电工技术 | 22篇 |
综合类 | 16篇 |
化学工业 | 321篇 |
金属工艺 | 46篇 |
机械仪表 | 111篇 |
建筑科学 | 43篇 |
矿业工程 | 13篇 |
能源动力 | 57篇 |
轻工业 | 102篇 |
水利工程 | 6篇 |
石油天然气 | 15篇 |
无线电 | 224篇 |
一般工业技术 | 282篇 |
冶金工业 | 144篇 |
原子能技术 | 17篇 |
自动化技术 | 222篇 |
出版年
2023年 | 20篇 |
2022年 | 26篇 |
2021年 | 39篇 |
2020年 | 33篇 |
2019年 | 33篇 |
2018年 | 40篇 |
2017年 | 43篇 |
2016年 | 37篇 |
2015年 | 33篇 |
2014年 | 54篇 |
2013年 | 122篇 |
2012年 | 70篇 |
2011年 | 102篇 |
2010年 | 80篇 |
2009年 | 90篇 |
2008年 | 88篇 |
2007年 | 75篇 |
2006年 | 55篇 |
2005年 | 64篇 |
2004年 | 52篇 |
2003年 | 37篇 |
2002年 | 44篇 |
2001年 | 29篇 |
2000年 | 27篇 |
1999年 | 27篇 |
1998年 | 45篇 |
1997年 | 49篇 |
1996年 | 36篇 |
1995年 | 22篇 |
1994年 | 22篇 |
1993年 | 16篇 |
1992年 | 4篇 |
1991年 | 11篇 |
1990年 | 4篇 |
1989年 | 9篇 |
1988年 | 17篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 8篇 |
1979年 | 4篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 8篇 |
排序方式: 共有1641条查询结果,搜索用时 26 毫秒
991.
Cucumber souring is a process mediated by a microorganisms present on the surface of cucumber fruits. Sour pickles are fresh cucumbers that have been poured over with a sodium chloride solution and various types of spices. In the present research, pre-ozonated and control cucumber fruits were subjected to the souring processes. It was observed that ozone treatment had no negative impact on the quality of the fruit before the souring process. Moreover, sour pickles after pre-ozonation had better mechanic and sensory properties than the control. 相似文献
992.
Hanhui Jin Bonan Xu Hanqing Li Xiaoke Ku Jianren Fan 《International Journal of Hydrogen Energy》2018,43(45):20513-20524
Studies on the coal gasification process in supercritical water (SCW) were carried out with the ReaxFF molecular dynamics (MD) method, in which the Wiser model of the coal molecule was adopted. The results show that hydrogen production increases with increase of temperature and water–coal mass ratio. It is also found that the coal molecule breaks into small fragments before it reacts with water molecules. The detailed chemical reactions and pathways of hydrogen generation during the gasification process are disclosed. H ions are found to be the main source of hydrogen generation, and C–H–O compounds or radicals are the most essential reactants throughout the reactions producing H2 and H ions. OH ions can significantly accelerate the oxidization of organic fragments to produce C–H–O compounds and radicals, which explains how catalysts of alkali salts such as NaOH and KOH improve hydrogen production. 相似文献
993.
994.
995.
Ku Cheung-Chieh Chen Guan-Wei 《International Journal of Control, Automation and Systems》2018,16(1):243-255
International Journal of Control, Automation and Systems - A robust delay-dependent stability criterion for discrete-time uncertain stochastic systems is proposed to achieve asymptotical stability... 相似文献
996.
Piezoelectric properties of (Na1−xKx)NbO3‐based lead‐free piezoelectric ceramics and their application in knocking sensor
下载免费PDF全文
![点击此处可从《Journal of the American Ceramic Society》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dae‐Hyeon Kim Tae‐Gon Lee Sung‐Hoon Cho Ku‐Tak Lee Chong‐Yun Kang Won‐Kyoung Lee Chung‐Kook Lee Sahn Nahm 《Journal of the American Ceramic Society》2017,100(12):5367-5373
Piezoelectric knocking sensors with a dense microstructure were fabricated at 960°C for 2 hours using various CuO‐added (Na0.5K0.5)NbO3 (NKN)‐based piezoelectric ceramics. The practical sensitivity (SP) of the knocking sensor, which is the ability to detect the knocking of a car engine, was influenced by the g33 × kp value of the piezoelectric ceramics, indicating that the g33 × kp can be considered a figure of merit of the piezoelectric ceramics used in the knocking sensor. The knocking sensor synthesized using the CuO‐added 0.95(Na0.5K0.5)(Nb0.95Sb0.05)O3–0.05CaTiO3 (CNKNS–CT) ceramic, which showed a g33 of 25.7 Vm/N and kp of 0.46, exhibited a high SP of 119 mV/g at the resonance frequency. The SP of the commercial knocking sensor, which was synthesized using the Pb(Zr,Ti)O3 (PZT)‐based ceramic, was 112 mV/g at the resonance frequency. Hence, the knocking sensor fabricated using the CNKNS–CT piezoelectric ceramic can be used to replace the commercial PZT‐based knocking sensor. 相似文献
997.
Wei-Liang Tay Chee-Kong Chui Sim-Heng Ong Alvin Choong-Meng Ng 《Expert systems with applications》2013,40(2):811-819
Areal bone mineral density (aBMD) is used in clinical practice to diagnose osteoporosis. In previous studies, aBMD was estimated from diagnostic computed tomography (dCT) images, but a battery of medical tests was also taken that can be used to improve the regression performance. However, it is difficult to exploit the multimodal data as the additional features have poor informativeness and may lead to overfitting. An ensemble-based framework is proposed to improve the regression accuracy and robustness on multimodal medical data with a high relative dimensionality. Instead of case-wise bootstrap aggregating, a filtering-based metalearner scheme was employed to build feature-wise ensembles. The proposed approach was evaluated on clinical data and was found to be superior to bagging and other ensemble methods. The feature-wise ensembling approach can also be used to automatically determine if any multimodal features are related to bone mineral density. Several blood measurements were identified to be linked with bone mineral density, and a literature search supported the automatic identification results. 相似文献
998.
999.
J. Ku?aga 《Journal of Dynamical and Control Systems》2012,18(2):247-267
We show an isomorphism stability property for Cartesian products of either flows with joining primeness property or flows which are ??-weakly mixing. 相似文献
1000.
Xin Lu Erjiang Hu Xiaojie Li Jinfeng Ku Zuohua Huang 《International Journal of Hydrogen Energy》2017,42(34):22036-22045
Both experimental and calculated laminar burning velocities of H2/O2/He mixtures were obtained, with equivalence ratios of 0.6–4.0, initial pressures of 0.1 MPa–0.5 MPa, initial temperature of 373 K, and dilution ratio of 7.0. Laminar burning velocities changed non-monotonically with the increasing initial pressures at equivalence ratios of 1.0–3.0. The decrease of overall reaction orders can explain the non-monotonic relationship between the laminar burning velocities and initial pressures. Consumption and production of both H and HO2 radicals were also obtained to explain the decrease of overall reaction order. The competition of H and HO2 radical between elemental reactions were also discussed. The three body reaction R15 (H + O2(+M) = HO2(+M)) gained more H radical in the competition with R1 (H + O2 = O + OH), producing more HO2 radical. Through the reaction pathway analysis, the restraint in production of both OH and H leaded to a reducing radical pool. The poorer reaction pool would restrain the overall reaction and lead to the reduction of overall reaction order and the non-monotonic behavior of the laminar burning velocity. 相似文献