全文获取类型
收费全文 | 5822篇 |
免费 | 874篇 |
国内免费 | 375篇 |
专业分类
电工技术 | 81篇 |
综合类 | 369篇 |
化学工业 | 1785篇 |
金属工艺 | 687篇 |
机械仪表 | 161篇 |
建筑科学 | 308篇 |
矿业工程 | 111篇 |
能源动力 | 191篇 |
轻工业 | 171篇 |
水利工程 | 98篇 |
石油天然气 | 696篇 |
武器工业 | 41篇 |
无线电 | 713篇 |
一般工业技术 | 1315篇 |
冶金工业 | 126篇 |
原子能技术 | 64篇 |
自动化技术 | 154篇 |
出版年
2024年 | 36篇 |
2023年 | 265篇 |
2022年 | 151篇 |
2021年 | 246篇 |
2020年 | 260篇 |
2019年 | 238篇 |
2018年 | 249篇 |
2017年 | 254篇 |
2016年 | 272篇 |
2015年 | 241篇 |
2014年 | 280篇 |
2013年 | 467篇 |
2012年 | 367篇 |
2011年 | 330篇 |
2010年 | 227篇 |
2009年 | 285篇 |
2008年 | 255篇 |
2007年 | 302篇 |
2006年 | 289篇 |
2005年 | 225篇 |
2004年 | 259篇 |
2003年 | 202篇 |
2002年 | 195篇 |
2001年 | 175篇 |
2000年 | 145篇 |
1999年 | 134篇 |
1998年 | 120篇 |
1997年 | 102篇 |
1996年 | 85篇 |
1995年 | 69篇 |
1994年 | 65篇 |
1993年 | 61篇 |
1992年 | 56篇 |
1991年 | 28篇 |
1990年 | 31篇 |
1989年 | 21篇 |
1988年 | 19篇 |
1987年 | 14篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1959年 | 2篇 |
1951年 | 4篇 |
排序方式: 共有7071条查询结果,搜索用时 15 毫秒
1.
《International Journal of Hydrogen Energy》2022,47(45):19758-19771
In this study, the effects of cell temperature and relative humidity on charge transport parameters are numerically analyzed. In order to perform this analysis, three-dimensional and anisotropic numerical models are developed. The numerical models are integrated into the experimental values for anisotropic electrical conductivities, as depending on cell temperature and relative humidity, that were obtained from our previous study. The achieved results indicate that the values of current densities in the in-plane direction increase with increasing cell temperature and relative humidity, while the current densities reach a maximum in the rib regions for both the numerical model at the through-plane direction. The behaviors of electrolyte potentials are similar with changes in the cell temperature and relative humidity. In addition, the cathode electrical potentials in both the in-plane direction and through-plane direction do not change to a considerable amount with increasing cell temperature and relative humidity. 相似文献
2.
Cuiping Yu Shuang Sun Sihui Li Huijia Yan Henan Zou 《International Journal of Food Science & Technology》2022,57(2):1173-1185
In this study, the effect of high-intensity ultrasound (HIUS) (200 and 400 W for 0, 5, 10 and 15 min respectively) on conformational changes, physicochemical, rheological and emulsifying properties of scallop (Patinopecten yessoensis) myofibrillar protein (SMP) was investigated. HIUS-treated SMP had lower α-helix content and higher β-sheet content compared with the native SMP. HIUS treatment induced the unfolding of SMP and increased the surface hydrophobicity. The particle size of SMP decreased and the absolute zeta-potential increased after ultrasonication, which in turn increased the solubility of SMP. The conformational changes and the improvement of physicochemical properties of SMP increased the ability for SMP to lower the interfacial tension at the oil–water interface and increased the percentage of adsorbed protein. As a result, the emulsifying properties, rheological properties of SMP and storage stability of emulsions were also improved. In conclusion, HIUS treatment has future potential for improving the emulsifying properties of SMP. 相似文献
3.
4.
Mizuki Tenjimbayashi Sadaki Samitsu Yuko Watanabe Yasuyuki Nakamura Masanobu Naito 《Advanced functional materials》2021,31(21):2010957
Liquid marble (LM) is a droplet that is wrapped by hydrophobic solid particles, which behave as a non-wetting soft solid. Based on these properties, LM can be applied in fluidics and soft device applications. A wide variety of functional particles have been synthesized to form functional LMs. However, the formation of multifunctional LMs by integrating several types of functional particles is challenging. Here, a general strategy for the flexible patterning of functional particles on droplet surfaces in a patchwork-like design is reported. It is shown that LMs can switch their macroscopic behavior between a stable and active state on super-repellent surfaces in situ by jamming/unjamming the surface particles. Active LMs hydrostatically coalesce to form a self-sorted particle pattern on the droplet surface. With the support of LM handling robotics, on-demand cyclic activation–manipulation–coalescence–stabilization protocols by LMs with different sizes and particle types result in the reliable design of multi-faced LMs. Based on this concept, a single bi-functional LM is designed from two mono-functional LMs as an advanced droplet carrier. 相似文献
5.
Yu Zhao Zhigang Xu Zongshi Li Weihong Qiao Lubai Cheng 《Petroleum Science and Technology》2006,24(7):821-827
Heavy alkyl benzene sulfonates (HABS) were synthesized, and their interfacial tensions were measured and compared with those of petroleum sulfonates ORS-41. Effects of their coupling with lignosulfonate were also studied. The results showed that HABS exhibited good interfacial activities and the system of HABS blending with LS displayed better interfacial activities than ORS-41 and therefore reduced the prime cost. Their best proportions of synergism were from 3:1 to 4:1. HABS might be a more promising alkali-surfactant-polymer (ASP) flooding agent. 相似文献
6.
龙口水利枢纽坝基岩体主要由奥陶系中统马家沟组(O2m2)灰岩组成,其中发育有多层软弱夹层。作为其中之一的钙质充填夹层,强度虽不很低,但由于处于坝基下的持力层内,间距不大,发育密集,产状平缓,是坝基浅层抗滑稳定的主要控制因素,因此,在大坝抗滑稳定分析时,应进行分析和研究。 相似文献
7.
对爆炸效应在淤泥软基工程中的应用问题进行了探讨,并首次提出了爆炸在淤泥软基中的分界应力特征以及排水固结及破坏分区的基本模式。为采用动力加速对淤泥软基工程的处理,提供了试验依据,具有实用价值和指导意义。 相似文献
8.
本文报道采用液相外延(LPE)生长和传统光刻制管工艺研制出引入多层(三层或三层以上)中间能带隙过渡的吸收区、倍增区分离的InGaAs(P)/InP雪崩光电二极管(简称InGaAs(P)/InPSAGMAPD),其技术指标为:击穿电压VB=40~90V;0.9VB时的暗电流Id最小可小于10nA;1.3μm时光响应度Re=0.6~0.8A/W,倍增因子M≥20(Mmax>40),过剩噪声因子F≌5和较宽频带响应特性。 相似文献
9.
用化学气相沉积法制备了液晶光阀中光电导层———非晶硅薄膜,从实验中得出最佳制备工艺的参数取值。给出了用包络线法测量非晶硅薄膜光吸收系数的原理,测量了样品的光吸收系数随波长的变化规律。得到样品在最佳工艺条件下的光吸收系数高于1×103cm-1。 相似文献
10.
Thin hard coatings fracture propagation during the impact test 总被引:2,自引:0,他引:2
One of the most significant applications of the impact test is to investigate thin hard coatings fatigue properties. Herein the test conditions and duration up to the film damage initiation, are considered in order to determine the critical stresses associated with the coating fatigue strength. Moreover, the subsequent film damage propagation is a significant mechanism as well, since it refers to the ability of the coating to withstand loads after its fatigue damage initiation. In order to describe the film fracture propagation the failed area ratio was introduced and an algorithm to determine this magnitude developed, based on the analysis of imprint scanning electron microscopy graphs. The application of the coating failed area ratio will be demonstrated in various impact test film cases, also with superficial thin layers. The top layers do not affect, in general, the failure initiation of the basic coating. However, according to the obtained results, the superficial films influence the basic coating failure propagation rate during the impact test. 相似文献