全文获取类型
收费全文 | 759235篇 |
免费 | 48060篇 |
国内免费 | 31484篇 |
专业分类
电工技术 | 40141篇 |
综合类 | 39989篇 |
化学工业 | 102135篇 |
金属工艺 | 42007篇 |
机械仪表 | 38676篇 |
建筑科学 | 34756篇 |
矿业工程 | 18256篇 |
能源动力 | 20658篇 |
轻工业 | 70095篇 |
水利工程 | 16519篇 |
石油天然气 | 20329篇 |
武器工业 | 5517篇 |
无线电 | 85554篇 |
一般工业技术 | 110893篇 |
冶金工业 | 92449篇 |
原子能技术 | 15426篇 |
自动化技术 | 85379篇 |
出版年
2023年 | 6910篇 |
2022年 | 16980篇 |
2021年 | 22333篇 |
2020年 | 15923篇 |
2019年 | 12702篇 |
2018年 | 15994篇 |
2017年 | 17845篇 |
2016年 | 16882篇 |
2015年 | 20400篇 |
2014年 | 27334篇 |
2013年 | 43796篇 |
2012年 | 41372篇 |
2011年 | 46715篇 |
2010年 | 41823篇 |
2009年 | 41888篇 |
2008年 | 43554篇 |
2007年 | 42414篇 |
2006年 | 36933篇 |
2005年 | 31259篇 |
2004年 | 24799篇 |
2003年 | 19666篇 |
2002年 | 18300篇 |
2001年 | 17309篇 |
2000年 | 15197篇 |
1999年 | 11728篇 |
1998年 | 25404篇 |
1997年 | 17410篇 |
1996年 | 13361篇 |
1995年 | 9876篇 |
1994年 | 8649篇 |
1993年 | 8709篇 |
1992年 | 6246篇 |
1991年 | 5846篇 |
1990年 | 5831篇 |
1989年 | 5470篇 |
1988年 | 5147篇 |
1987年 | 4504篇 |
1986年 | 4366篇 |
1985年 | 4865篇 |
1984年 | 4453篇 |
1983年 | 4033篇 |
1982年 | 3701篇 |
1981年 | 3806篇 |
1980年 | 3549篇 |
1979年 | 3394篇 |
1978年 | 3338篇 |
1977年 | 3810篇 |
1976年 | 4959篇 |
1975年 | 2857篇 |
1973年 | 2731篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Dr. Thomas Le Bihan Dr. Cathryn H. S. Driver Dr. Thomas Ebenhan Dr. Nathalie Le Bris Dr. Jan Rijn Zeevaart Prof. Dr. Raphaël Tripier 《ChemMedChem》2021,16(5):809-821
An improved glucose-chelator-albumin bioconjugate (GluCAB) derivative, GluCAB-2Mal, has been synthesized and studied for in vivo 64Cu-PET/CT imaging in breast cancer mice models together with its first-generation analogue GluCAB-1Mal. The radioligand works on the principle of tumor targeting through the enhanced permeability and retention (EPR) effect with a supportive role played by glucose metabolism. [64Cu]Cu-GluCAB-2Mal (99 % RCP) exhibited high serum stability with immediate binding to serum proteins. In vivo experiments for comparison between tumor targeting of [64Cu]Cu-GluCAB-2Mal and previous-generation [64Cu]Cu-GluCAB-1Mal encompassed microPET/CT imaging and biodistribution analysis in an allograft E0771 breast cancer mouse model. Tumor uptake of [64Cu]Cu-GluCAB-2Mal was clearly evident with twice as much accumulation as compared to its predecessor and a tumor/muscle ratio of up to 5 after 24 h. Further comparison indicated a decrease in liver accumulation for [64Cu]Cu-Glu-CAB-2Mal. 相似文献
32.
Zhuchkov V. I. Nazansky S. L. Frolkova A. K. Ganina K. D. 《Theoretical Foundations of Chemical Engineering》2021,55(4):786-791
Theoretical Foundations of Chemical Engineering - Using gas–liquid chromatography, the activity coefficients upon the infinite dilution of the components of the reaction mixture for obtaining... 相似文献
33.
Reliable joints of Ti3SiC2 ceramic and TC11 alloy were diffusion bonded with a 50 μm thick Cu interlayer. The typical interfacial structure of the diffusion boned joint, which was dependent on the interdiffusion and chemical reactions between Al, Si and Ti atoms from the base materials and Cu interlayer, was TC11/α-Ti + β-Ti + Ti2Cu + TiCu/Ti5Si4 + TiSiCu/Cu(s, s)/Ti3SiC2. The influence of bonding temperature and time on the interfacial structure and mechanical properties of Ti3SiC2/Cu/TC11 joint was analyzed. With the increase of bonding temperature and time, the joint shear strength was gradually increased due to enhanced atomic diffusion. However, the thickness of Ti5Si4 and TiSiCu layers with high microhardness increased for a long holding time, resulting in the reduction of bonding strength. The maximum shear strength of 251 ± 6 MPa was obtained for the joint diffusion bonded at 850 °C for 60 min, and fracture primarily occurred at the diffusion layer adjacent to the Ti3SiC2 substrate. This work provided an economical and convenient solution for broadening the engineering application of Ti3SiC2 ceramic. 相似文献
34.
Catalysis Letters - An environmentally benign process for synthesizing 4-methoxyphenol through methylation of hydroquinone using polystyrene immobilized Bronsted acidic ionic liquid is presented.... 相似文献
35.
Felipe A. Perdomo Siti H. Khalit Claire S. Adjiman Amparo Galindo George Jackson 《American Institute of Chemical Engineers》2021,67(3):e17194
The SAFT-γ Mie group-contribution equation of state is used to represent the fluid-phase behavior of aqueous solutions of a variety of linear, branched, and cyclic amines. New group interactions are developed in order to model the mixtures of interest, including the like and unlike interactions between alkyl primary, secondary, and tertiary amine groups (NH2, NH, N), cyclic secondary and tertiary amine groups (cNH, cN), and cyclic methine-amine groups (cCHNH, cCHN) with water (H2O). The group-interaction parameters are estimated from appropriate experimental thermodynamic data for pure amines and selected mixtures. By taking advantage of the group-contribution nature of the method, one can describe the fluid-phase behavior of mixtures of molecules comprising those groups over broad ranges of temperature, pressure, and composition. A number of aqueous solutions of amines are studied including linear, branched aliphatic, and cyclic amines. Liquid–liquid equilibria (LLE) bounded by lower critical solution temperatures (LCSTs) have been reported experimentally and are reproduced here with the SAFT-γ Mie approach. The main feature of the approach is the ability not only to represent accurately the experimental data employed in the parameter estimation, but also to predict the vapor–liquid, liquid–liquid, and vapor–liquid–liquid equilibria, and LCSTs with the same set of parameters. Pure compound and binary phase diagrams of diverse types of amines and their aqueous solutions are assessed in order to demonstrate the main features of the thermodynamic and fluid-phase behavior. 相似文献
36.
Bosyakova N. A. Pomortsev S. A. Gizatullin R. G. Klyosov Yu. L. Laptov S. V. Kashcheev I. D. Zemlyanoi K. G. 《Refractories and Industrial Ceramics》2021,62(4):381-383
Refractories and Industrial Ceramics - Technology for producing alumina-periclase-carbon refractories of the brands APUK-D and APU-D is developed and implemented. Use of complex antioxidant and... 相似文献
37.
38.
碎片化学习难以集中记录,存在无法迅速定位到自己需要的学习内容等用户体验问题.传统方法不能采集真实情境下的用户数据,无法满足研究人员的研究需求.基于此,开发一种基于用户行为的捕捉工具——CAUX(Context-Aware User Experience,CAUX),设计了具有情境感知能力的数据采集模块,自动捕捉指定App内的用户行为数据.CAUX对用户干扰性低,可以辅助研究人员捕捉典型的碎片化学习行为.对利用CAUX采集到的数据进行处理,并结合人工方法进行分析,可以发现不同情境下的用户行为和用户体验问题. 相似文献
39.
基于柴油产品质量升级的需求,中国石化大连石油化工研究院(FRIPP)开发了FHIDW加氢改质技术及配套FF-46加氢精制催化剂、FC-14B加氢改质催化剂和FDW-3临氢降凝催化剂.该技术及催化剂级配体系在格尔木炼油厂0.8 Mt·a-1加氢改质装置上的工业应用情况表明,级配催化剂体系对原料适应性强,装置运转平稳,操作灵活性高,催化剂失活速率慢,产品分布合理且质量优异,在降低柴油产品凝点的同时可以明显改善其密度和十六烷值,解决了改造前装置生产重柴油密度偏低的问题,为炼油厂生产符合国V质量标准的柴油提供了技术保障. 相似文献
40.