全文获取类型
收费全文 | 5632篇 |
免费 | 236篇 |
国内免费 | 14篇 |
专业分类
电工技术 | 88篇 |
综合类 | 27篇 |
化学工业 | 1572篇 |
金属工艺 | 109篇 |
机械仪表 | 107篇 |
建筑科学 | 342篇 |
矿业工程 | 23篇 |
能源动力 | 111篇 |
轻工业 | 454篇 |
水利工程 | 35篇 |
石油天然气 | 2篇 |
无线电 | 361篇 |
一般工业技术 | 1149篇 |
冶金工业 | 636篇 |
原子能技术 | 49篇 |
自动化技术 | 817篇 |
出版年
2023年 | 41篇 |
2022年 | 47篇 |
2021年 | 96篇 |
2020年 | 78篇 |
2019年 | 72篇 |
2018年 | 95篇 |
2017年 | 102篇 |
2016年 | 152篇 |
2015年 | 111篇 |
2014年 | 173篇 |
2013年 | 268篇 |
2012年 | 236篇 |
2011年 | 338篇 |
2010年 | 265篇 |
2009年 | 270篇 |
2008年 | 266篇 |
2007年 | 256篇 |
2006年 | 245篇 |
2005年 | 217篇 |
2004年 | 190篇 |
2003年 | 145篇 |
2002年 | 120篇 |
2001年 | 91篇 |
2000年 | 100篇 |
1999年 | 115篇 |
1998年 | 158篇 |
1997年 | 112篇 |
1996年 | 113篇 |
1995年 | 77篇 |
1994年 | 77篇 |
1993年 | 81篇 |
1992年 | 83篇 |
1991年 | 64篇 |
1990年 | 63篇 |
1989年 | 62篇 |
1988年 | 70篇 |
1987年 | 62篇 |
1986年 | 53篇 |
1985年 | 53篇 |
1984年 | 58篇 |
1983年 | 40篇 |
1982年 | 48篇 |
1981年 | 50篇 |
1980年 | 35篇 |
1979年 | 30篇 |
1978年 | 35篇 |
1977年 | 35篇 |
1976年 | 50篇 |
1975年 | 40篇 |
1973年 | 37篇 |
排序方式: 共有5882条查询结果,搜索用时 15 毫秒
1.
This DFG-funded research project aimed to gain a better understanding of the mechanisms of the W-Cl repair principle within the framework of fundamental investigations, to contribute to the creation of the necessary basis for a broader application of the repair principle in practice. The focus was on the development of a model to describe the chloride redistribution after the application of a system sealing surface protective coating. On the basis of Fick's second law of diffusion, a mathematical model with a self-contained analytical solution was developed, with the help of which the chloride redistribution after application of a system sealing surface protective coating can be calculated under the idealized assumption of complete water saturation of the concrete. Furthermore, the influence of the dehydration of the concrete, expected as a result of the application of the repair principle W-Cl, on the chloride redistribution was investigated. On the basis of laboratory tests and numerical simulations, material-specific reduction functions were developed to quantify the relationship between the chloride diffusion coefficient and the ambient humidity. 相似文献
2.
A heavy crude oil has been treated with deuterated alkylating reagents (CD3I and C2D5I) and directly analyzed without any prior fractionation and chromatographic separation by high-field Orbitrap Fourier Transform Mass Spectrometry (FTMS) and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) using electrospray ionization (ESI). The reaction of a polycyclic aromatic sulfur heterocycles (PASHs) dibenzothiophene (DBT), in the presence of silver tetrafluoroborate (AgBF4) with ethyl iodide (C2H5I) in anhydrous dichloroethane (DCE) was optimized as a sample reaction to study heavy crude oil mixtures, and the reaction yield was monitored and determined by proton nuclear magnetic resonance spectroscopy (1H-NMR). The obtained conditions were then applied to a mixture of standard aromatic CH-, N-, O- and S-containing compounds and then a heavy crude oil, and only sulfur-containing compounds were selectively alkylated. The deuterium labeled alkylating reagents, iodomethane-d3 (CD3I) and iodoethane-d5 (C2D5I), were employed to the alkylation of heavy crude oil to selectively differentiate the tagged sulfur species from the original crude oil. 相似文献
3.
4.
Dr. Hui Qiu Richard Caldwell Dr. Lesley Liu-Bujalski Dr. Andreas Goutopoulos Reinaldo Jones Justin Potnick Dr. Brian Sherer Dr. Andrew Bender Dr. Roland Grenningloh Dr. Daigen Xu Dr. Anna Gardberg Dr. Igor Mochalkin Dr. Theresa Johnson Dr. Ariele Viacava Follis Jared Head Dr. Federica Morandi 《ChemMedChem》2019,14(2):217-223
Bruton's tyrosine kinase (Btk) is an attractive target for the treatment of a wide array of B-cell malignancies and autoimmune diseases. Small-molecule covalent irreversible Btk inhibitors targeting Cys481 have been developed for the treatment of such diseases. In clinical trials, probe molecules are required in occupancy studies to measure the level of engagement of the protein by these covalent irreversible inhibitors. The result of this pharmacodynamic (PD) activity provides guidance for appropriate dosage selection to optimize inhibition of the drug target and correlation of target inhibition with disease treatment efficacy. This information is crucial for successful evaluation of drug candidates in clinical trials. Based on the pyridine carboxamide scaffold of a novel solvent-accessible pocket (SAP) series of covalent irreversible Btk inhibitors, we successfully developed a potent and selective affinity-based biotinylated probe 12 (2-[(4-{4-[5-(1-{5-[(3aS,4S,6aR)-2-oxo-hexahydro-1H-thieno[3,4-d]imidazol-4-yl]pentanamido}-3,6,9,12-tetraoxapentadecan-15-amido)pentanoyl]piperazine-1-carbonyl}phenyl)amino]-6-[1-(prop-2-enoyl)piperidin-4-yl]pyridine-3-carboxamide). Compound 12 has been used in Btk occupancy assays for preclinical studies to determine the therapeutic efficacy of Btk inhibition in two mouse lupus models driven by TLR7 activation and type I interferon. 相似文献
5.
Locke Davenport Huyer Serena Mandla Yufeng Wang Scott B. Campbell Bess Yee Christian Euler Benjamin F. Lai A. Dawn Bannerman Dawn S. Y. Lin Miles Montgomery Kayla Nemr Timothy Bender Slava Epelman Radhakrishnan Mahadevan Milica Radisic 《Advanced functional materials》2021,31(6):2003341
Itaconate (ITA) is an emerging powerhouse of innate immunity with therapeutic potential that is limited in its ability to be administered in a soluble form. A library of polyester materials that incorporate ITA into polymer backbones resulting in materials with inherent immunoregulatory behavior is developed. Harnessing hydrolytic degradation release from polyester backbones, ITA polymers result in the mechanism specific immunoregulatory properties on macrophage polarization in vitro. In a functional assay, the polymer-released ITA inhibits bacterial growth on acetate. Translation to an in vivo model of biomaterial associated inflammation, intraperitoneal injection of ITA polymers demonstrate a rapid resolution of inflammation in comparison to a control polymer silicone, demonstrating the value of sustained biomimetic presentation of ITA. 相似文献
6.
Wolfgang Wendler 《电子产品世界》2006,(17):129-130
与美国同行争分夺秒抢占市场先机不同,欧洲测量仪器厂商Rohde&Schwarz公司的产品策略则相对稳健,他们的产品更专注于功能的多样化 相似文献
7.
8.
9.
Ohne Zusammenfassung 相似文献
10.
Types of crystallizers . In the industrial application of single mass crystallization from solution clear aims exist with regard to crystallizate qualities. To fulfil these aims, one can choose between various types of crystallizers. Magma types, i.e. agitated tank crystallizer, forced circulation and draft tube (baffle) crystallizer, as well as classifying types with the well-known Oslo-crystallizer belong to the present state of the art. The rates of secondary nucleation decrease in the same sequence as that given above and the possibilities of influencing crystal size distributions increase, and coarser crystals are produceable. 相似文献