全文获取类型
收费全文 | 1060篇 |
免费 | 76篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 16篇 |
综合类 | 2篇 |
化学工业 | 285篇 |
金属工艺 | 31篇 |
机械仪表 | 74篇 |
建筑科学 | 11篇 |
能源动力 | 42篇 |
轻工业 | 95篇 |
水利工程 | 3篇 |
石油天然气 | 2篇 |
无线电 | 123篇 |
一般工业技术 | 254篇 |
冶金工业 | 42篇 |
原子能技术 | 9篇 |
自动化技术 | 159篇 |
出版年
2024年 | 6篇 |
2023年 | 36篇 |
2022年 | 91篇 |
2021年 | 125篇 |
2020年 | 82篇 |
2019年 | 93篇 |
2018年 | 74篇 |
2017年 | 53篇 |
2016年 | 76篇 |
2015年 | 49篇 |
2014年 | 57篇 |
2013年 | 60篇 |
2012年 | 54篇 |
2011年 | 45篇 |
2010年 | 25篇 |
2009年 | 26篇 |
2008年 | 23篇 |
2007年 | 22篇 |
2006年 | 14篇 |
2005年 | 6篇 |
2004年 | 13篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 9篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 13篇 |
1993年 | 3篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有1148条查询结果,搜索用时 15 毫秒
81.
Yasir Wu Ning Ali Zain Anwar Shaikh Muhammad Mujtaba Yahya Muhammad Rehan Aamir Muhammad 《Wireless Personal Communications》2019,106(4):1787-1800
Wireless Personal Communications - This paper proposes highly compact and high speed hardware architectures of 64-bit KASUMI block cipher for wide range of wireless applications. A novel... 相似文献
82.
Modeling and simulation of intracellular dynamics: choosing an appropriate framework 总被引:2,自引:0,他引:2
Systems biology is a reemerging paradigm which, among other things, focuses on mathematical modeling and simulation of biochemical reaction networks in intracellular processes. For most simulation tools and publications, they are usually characterized by either preferring stochastic simulation or rate equation models. The use of stochastic simulation is occasionally accompanied with arguments against rate equations. Motivated by these arguments, we discuss in this paper the relationship between these two forms of representation. Toward this end, we provide a novel compact derivation for the stochastic rate constant that forms the basis of the popular Gillespie algorithm. Comparing the mathematical basis of the two popular conceptual frameworks of generalized mass action models and the chemical master equation, we argue that some of the arguments that have been put forward are ignoring subtle differences and similarities that are important for answering the question in which conceptual framework one should investigate intracellular dynamics. 相似文献
83.
84.
Shaikh Mohd Rizwan Uddin Loan Sajad A. Alharbi Abdullah G. 《Journal of Computational Electronics》2021,20(6):2360-2368
Journal of Computational Electronics - In this work, a Schottky junction on the drain side employing low workfunction (WF) metal is proposed as a method to suppress the OFF-state leakage in... 相似文献
85.
In this paper, lead-free (1-x)(Bi0.5Na0.5)0.94Ba0.06TiO3-xBiAlO3 (BNBT-BA, x?=?0, 0.010, 0.015, 0.020, 0.025, and 0.030) piezoelectric ceramics were synthesized using a conventional solid-state reaction method. The effect of BiAlO3 concentration on dielectric, ferroelectric and piezoelectric properties were investigated. The ferroelectric and piezoelectric properties of BNBT ceramics are significantly influenced by the presence of BA. In the composition range studied, X-ray diffraction revealed a perovskite phase with the coexistence of rhombohedral and tetragonal phases. The temperature dependence of dielectric properties showed that the depolarization temperature (T d) shifted towards lower temperatures and that the degree of diffuseness of the phase transition around T d and T m became more obvious with increasing BiAlO3 content. The remanent polarization increased with increasing BA, and reached a maximum value of 30 μC/cm2 at x?=?0.020. As a result, at x?=?0.020, the piezoelectric constant (d 33) and the electromechanical coupling factor (k p) of the ceramics attained maximum values of 188 pC/N and 34.4 %, respectively. These results indicate that BNBT-BA ceramics is a promising candidate for lead-free piezoelectric materials. 相似文献
86.
87.
88.
Electrospinning of polycaprolactone nanofibers using H2O as benign additive in polycaprolactone/glacial acetic acid solution 下载免费PDF全文
Considerable efforts have been devoted to the production of polycaprolactone (PCL) nanofibrous structures by electrospinning. However, some toxic solvents have often been used to achieve bead‐free nanofibers. At present, a benign solvent such as glacial acetic acid (GAC) only leads to beaded or microscale fibers. Therefore a study is done to extend the electrospinnability of the PCL/GAC system by the addition of H2O. The solution properties of conductivity, viscosity, and surface tension were altered by the addition of H2O, especially increasing the conductivity and viscosity. These properties essential to electrospinning could remain stable for 6 h when the H2O content was less than or equal to 9 vol %. Then ultrafine PCL fibers with diameters from 188 to 200 nm, 10 times smaller than when dissolved in pure GAC, were electrospun from solutions of PCL with concentrations in the range of 17 to 20 wt % with H2O content at 9 vol %. Finally, the crystallinity and crystallite size of the resulting fibers were smaller than that of raw PCL pellets. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45578. 相似文献
89.
Saif Ullah Pierrick Anthony Mindykowski Rolff Ripke Leisted Sergey Chernyy Sie Woldum Tordrup Grunde Jomaas Kristoffer Almdal 《火与材料》2020,44(7):966-974
A novel intumescent (carbonization, acid donor and foaming) fire retardant that mimics carbon nanotubes was introduced into bitumen roofing and characterized using cone calorimetry as the main analytical tool. The experimental results indicate that 18% (by mass) attapulgite mineral (ATTP) mixed with base bitumen decreased the peak heat release rate per unit area (pHRRPUA) by 10%. Further, incorporation of melamine coated ammonium polyphosphate (MAPP) decreased the pHRRPUA by 52% and a mixture of these (3:1, ATTP:MAPP) decreased the pHRRPUA by 25% as compared to adding CaCO3 as a filler. The residual mass loss after the cone test was also improved with up to 3%. The indication of a positive synergistic flame retardant effect of the ATTP-MAPP mixture is supported by thermogravimetric analysis. The addition of this rod-like mineral improved the general fire retardant properties of the base bitumen and increased the viscosity. Therefore, the polymer-modified bitumen with both fire retardant and rheological properties (providing mechanical strength) is a promising novel approach in the design of bitumen roofing membranes. 相似文献
90.
Muhammad Idrees Saima Batool Qaiser Hussain Hidayat Ullah Mohammad Ibrahim Al-Wabel Mahtab Ahmad 《分离科学与技术》2016,51(14):2307-2317
Farmyard manure (FYM-BC) and poultry manure (PM-BC) derived biochars were applied as adsorbents to remove Cd2+ from water. Results indicated that PM-BC was a more efficient adsorbent than FYM-BC at all experimental conditions. Maximum Cd2+ adsorption was observed at pH 4, temperature 318 K and contact time 1 h, regardless of biochar type. The Langmuir model predicted maximum adsorption capacity of 90.09 mg g?1 for PM-BC. The data fitting to pseudo-second-order model proposed chemisorption of Cd2+ onto biochars. Thermodynamics indicated that adsorption was spontaneous and endothermic. Post-adsorption analysis provided evidences of strong chemical interactions between biochars’ functional groups and Cd2+ ions. 相似文献