全文获取类型
收费全文 | 428106篇 |
免费 | 39074篇 |
国内免费 | 17834篇 |
专业分类
电工技术 | 26152篇 |
技术理论 | 73篇 |
综合类 | 27701篇 |
化学工业 | 69097篇 |
金属工艺 | 24856篇 |
机械仪表 | 28835篇 |
建筑科学 | 33513篇 |
矿业工程 | 14170篇 |
能源动力 | 13077篇 |
轻工业 | 25873篇 |
水利工程 | 7770篇 |
石油天然气 | 27163篇 |
武器工业 | 3813篇 |
无线电 | 49235篇 |
一般工业技术 | 50089篇 |
冶金工业 | 21933篇 |
原子能技术 | 5070篇 |
自动化技术 | 56594篇 |
出版年
2025年 | 52篇 |
2024年 | 5392篇 |
2023年 | 7680篇 |
2022年 | 11687篇 |
2021年 | 16761篇 |
2020年 | 13408篇 |
2019年 | 10296篇 |
2018年 | 11791篇 |
2017年 | 13435篇 |
2016年 | 12306篇 |
2015年 | 16294篇 |
2014年 | 21012篇 |
2013年 | 25062篇 |
2012年 | 26971篇 |
2011年 | 29982篇 |
2010年 | 26376篇 |
2009年 | 25196篇 |
2008年 | 24901篇 |
2007年 | 24148篇 |
2006年 | 24473篇 |
2005年 | 21015篇 |
2004年 | 14016篇 |
2003年 | 12115篇 |
2002年 | 11080篇 |
2001年 | 9963篇 |
2000年 | 9883篇 |
1999年 | 10912篇 |
1998年 | 8893篇 |
1997年 | 7387篇 |
1996年 | 6867篇 |
1995年 | 5767篇 |
1994年 | 4713篇 |
1993年 | 3342篇 |
1992年 | 2666篇 |
1991年 | 2101篇 |
1990年 | 1608篇 |
1989年 | 1334篇 |
1988年 | 1080篇 |
1987年 | 742篇 |
1986年 | 596篇 |
1985年 | 365篇 |
1984年 | 264篇 |
1983年 | 231篇 |
1982年 | 213篇 |
1981年 | 148篇 |
1980年 | 145篇 |
1979年 | 74篇 |
1978年 | 36篇 |
1977年 | 46篇 |
1976年 | 58篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
982.
Yuyang Wang Hui Nie Jinsong Han Yaxun An Yu-Mo Zhang Sean Xiao-An Zhang 《光:科学与应用(英文版)》2021,10(3):327-340
The technological revolution of long-awaited energy-saving and vision-friendly displays represented by bistable display technology is conning.Here we discuss methods,challenges,and opportunities for implementing bistable displays in terms of molecular design,device structure,further expansion,and required criteria,hopefully benefiting the light-related community. 相似文献
983.
近几年各个三坐标测量软件开发厂商相继在自己的软件中加入了CAD功能,且功能越来越强大。本文就CAD在三坐标测量软件中的使用和其功能作简要阐述。 相似文献
984.
我国粮油机械工业的发展与"走出去"战略实施 总被引:1,自引:1,他引:0
回顾了我国粮油机械工业的发展历史,提出了“走出去”是我国粮油机械工业新的发展趋势,论述了实施“走出去”战略的可行性,并对具体实施提出合理建议。 相似文献
985.
Ying Yang Hui-Yun Chen Hua Hao Ke-Jian Wang 《International journal of molecular sciences》2022,23(10)
Scyreprocin is an antimicrobial peptide first identified in the mud crab Scylla paramamosain. Herein, we showed that its recombinant product (rScyreprocin) could significantly inhibit the growth of human lung cancer NCI-H460 cells (H460), but showed no cytotoxicity to human lung fibroblasts (HFL1). rScyreprocin was a membrane-active peptide that firstly induced the generation of reactive oxygen species (ROS) in H460, and led to endoplasmic reticulum stress and Ca2+ release, which resulted in mitochondrial dysfunction and subsequently activation of caspase-3 cascades, and ultimately led to apoptosis. The comprehensive results indicated that rScyreprocin exerted anticancer activity by disrupting cell membrane and inducing apoptosis. The in vivo efficacy test demonstrated that intratumoral injection of rScyreprocin significantly inhibited the growth of H460 xenografts, which was close to that of the cisplatin (inhibition rate: 69.94% vs. 80.76%). Therefore, rScyreprocin is expected to become a promising candidate for the treatment of lung cancer. 相似文献
986.
Lu Jin Yang Yao Sun Jingyuan Huang Zhengliang Yang Yongrong Wang Jingdai 《中国炼油与石油化工》2022,(1):135-148
The hydrodynamic instability of the axial flow pump in a loop reactor has long been a troubling issue to be solved in the polyethylene industry due to the lack of a better mechanismic understanding.Generally,the instability of an axial flow pump can be reflected by the fluctuation of the pump head.In this study,the transient computational fluid dynamics(CFD)simulation is adopted to study the hydrodynamic instability of the axial flow pump used in an ethylene polymerization loop reactor.The resul... 相似文献
987.
In recent years,a new generation of storage ring-based light sources,known as diffraction-limited storage rings(DLSRs),whose emittance approaches the diffractio... 相似文献
988.
Jin Shu Mao Xiang Hui Wang Kang De Yao Qing Xin Shang Guang Hui Yang 《Journal of Materials Science》2003,38(10):2283-2290
The culture of keratinocytes on flexible membranes has been proposed as a means to simplify, accelerate and improve the efficiency with which proliferating cells are delivered to full thickness or non-healing skin defects. The purpose of this article was to study the ability of chitosan-gelatin manbranes to facilitate the growth of human keratinocytes. The membranes with different chitosan contents were studied. The surface properties of chitosan-gelatin membranes were investigate by SEM, and water contact angle test. The mechanical property of the membranes was tested. Data implied that gelatin could make the membranes more flexible and hydrophilic than chitosan membranes, which may regulate the seeded cells behavior. Loading human keratinocytes on chitosan-gelatin membranes, cells attachment, spread, and growth were investigated by light microscopy, SEM, and MTT test. The results suggested that the adhesion and proliferation of keratinocytes seeded on chitosan-gelatin membranes were same as on tissue culture plate, in which gelatin could modify the interaction between keratinocytes and chitosan membranes. Therefore, chitosan-gelatin membrane is a good candidate for keratinocytes delivery system. 相似文献
989.
基于有限元法、Arbitrary Lagrangian-Eulerian有限元网格变形法理论及White-Metzner粘弹性本构方程,采用Moldex软件进行了变厚度光学透镜成型的三维仿真分析。模拟表明,压缩阶段的挤压流存在显著三维流动特征,较常规注射,注射压缩能有效地降低注射压力、剪切率与流动残余应力及因此造成的翘曲和光程差。减小压缩速度使压缩阶段浇口压力升高较小、熔体剪切作用减弱;增大压缩距离,可以降低注射压力,减弱剪切作用。实际上这些变量在厚度和距离浇口不同位置的分布不同。 相似文献
990.
Donglin He Ping Li Wei Wang Qi Wan Jian Zhang Kai Xi Xiumei Ma Zhiwei Liu Lin Zhang Xuanhui Qu 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(5)
Although silicon‐based materials are ideal candidate anodes for high energy density lithium‐ion batteries, the large volumetric expansion seriously damages the integrity of the electrodes and impedes commercial processes. Reasonable electrode design based on adjustable structures of silicon and strong binders prepared by a facile method is still a great challenge. Herein, a three‐pronged collaborative strategy via hollow nanocubes, amorphous Void@SiOx@C, and in situ cross‐linked polyacrylic acid and d ‐sorbitol 3D network binder (c‐PAA‐DS) is adopted to maintain structural/electrode integrality and stability. The all‐integrated c‐PAA‐DS/Void@SiOx@C electrode delivers excellent mechanical property, which is attributed to ductility of the c‐PAA‐DS binder and high adhesion energy between Void@SiOx@C and c‐PAA‐DS calculated by density functional theory. Benefiting from the synergistic effect of accommodation of the hollow structure, protection of outer carbon shell, amorphous Void@SiOx@C, and strong adhesive c‐PAA‐DS binder, c‐PAA‐DS/Void@SiOx@C shows excellent electrochemical performance. Long cycling stability with a reversible capacity of 696 mAh g?1 is obtained, as well as tiny capacity decay after 500 cycles at 0.5 A g?1 and high‐rate performance. The prelithiated Void@SiOx@C||LiNi0.5Co0.2Mn0.3O2 (NCM523) full cell is also assembled and shows a reversible capacity of 157 mAh g?1 at 0.5 C, delivering an excellent capacity retention of 94% after 160 cycles. 相似文献