全文获取类型
收费全文 | 4929篇 |
免费 | 401篇 |
国内免费 | 323篇 |
专业分类
电工技术 | 77篇 |
综合类 | 203篇 |
化学工业 | 1307篇 |
金属工艺 | 443篇 |
机械仪表 | 193篇 |
建筑科学 | 287篇 |
矿业工程 | 27篇 |
能源动力 | 301篇 |
轻工业 | 372篇 |
水利工程 | 36篇 |
石油天然气 | 16篇 |
武器工业 | 16篇 |
无线电 | 1146篇 |
一般工业技术 | 843篇 |
冶金工业 | 115篇 |
原子能技术 | 29篇 |
自动化技术 | 242篇 |
出版年
2024年 | 24篇 |
2023年 | 63篇 |
2022年 | 105篇 |
2021年 | 114篇 |
2020年 | 152篇 |
2019年 | 133篇 |
2018年 | 137篇 |
2017年 | 170篇 |
2016年 | 187篇 |
2015年 | 214篇 |
2014年 | 274篇 |
2013年 | 393篇 |
2012年 | 329篇 |
2011年 | 448篇 |
2010年 | 280篇 |
2009年 | 288篇 |
2008年 | 289篇 |
2007年 | 324篇 |
2006年 | 290篇 |
2005年 | 234篇 |
2004年 | 224篇 |
2003年 | 169篇 |
2002年 | 122篇 |
2001年 | 109篇 |
2000年 | 112篇 |
1999年 | 83篇 |
1998年 | 68篇 |
1997年 | 34篇 |
1996年 | 57篇 |
1995年 | 42篇 |
1994年 | 38篇 |
1993年 | 27篇 |
1992年 | 20篇 |
1991年 | 17篇 |
1990年 | 24篇 |
1989年 | 16篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 2篇 |
1985年 | 7篇 |
1984年 | 10篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有5653条查询结果,搜索用时 13 毫秒
1.
Dr. Sandra Liebscher Dr. Sebastian Mathea Dr. Tobias Aumüller Dr. Andreas Pech Prof. Dr. Frank Bordusa 《Chembiochem : a European journal of chemical biology》2021,22(7):1201-1204
Fluorescent fusion proteins are powerful tools for studying biological processes in living cells, but universal application is limited due to the voluminous size of those tags, which might have an impact on the folding, localization or even the biological function of the target protein. The designed biocatalyst trypsiligase enables site-directed linkage of small-sized fluorescence dyes on the N terminus of integral target proteins located in the outer membrane of living cells through a stable native peptide bond. The function of the approach was tested by using the examples of covalent derivatization of the transmembrane proteins CD147 as well as the EGF receptor, both presented on human HeLa cells. Specific trypsiligase recognition of the site of linkage was mediated by the dipeptide sequence Arg-His added to the proteins’ native N termini, pointing outside the cell membrane. The labeling procedure takes only about 5 minutes, as demonstrated for couplings of the fluorescence dye tetramethyl rhodamine and the affinity label biotin as well. 相似文献
2.
Chenglai Xin Rong Yuan Jiang Wu Qingyuan Wang Yanan Zhou 《Ceramics International》2021,47(3):3411-3420
A novel method for fabricating a nano-Cu/Si3N4 ceramic substrate is proposed. The nano-Cu/Si3N4 ceramic substrate is first fabricated using spark plasma sintering (SPS) with the addition of nanoscale multilayer films (Ti/TiN/Ti/TiN/Ti) as transition layers. The microstructures of the nano-Cu metal layer and the interface between Cu and Si3N4 are investigated. The results show that a higher SPS temperature increases the grain size of the nano-Cu metal layer and affects the hardness. The microstructure of the transition layer evolves significantly after SPS. Ti in the transition layer can react with Si3N4 and with nano-Cu to form interfacial reaction layers of TiN and Ti–Cu, respectively; these ensure stronger bonding between nano-Cu and Si3N4. Higher SPS temperatures improve the diffusion ability of Ti and Cu, inducing the formation of Ti3Cu3O compounds in the nano-Cu metal layer and Ti2Cu in the transition layer. This study provides an important strategy for designing and constructing a new type of ceramic substrate. 相似文献
3.
Dr. Emrah Kara Dr. Nis Valentin Nielsen Bergrun Eggertsdottir Dr. Bernd Thiede Dr. Sandip M. Kanse Dr. Geir Åge Løset 《Chembiochem : a European journal of chemical biology》2020,21(13):1875-1884
We describe a novel, easy and efficient combinatorial phage display peptide substrate-mining method to map the substrate specificity of proteases. The peptide library is displayed on the pVII capsid of the M13 bacteriophage, which renders pIII necessary for infectivity and efficient retrieval, in an unmodified state. As capture module, the 3XFLAG was chosen due to its very high binding efficiency to anti-FLAG mAbs and its independency of any post-translational modification. This library was tested with Factor-VII activating protease (WT-FSAP) and its single-nucleotide polymorphism variant Marburg-I (MI)-FSAP. The WT-FSAP results confirmed the previously reported Arg/Lys centered FSAP cleavage site consensus as dominant, as well as reinforcing MI-FSAP as a loss-of-function mutant. Surprisingly, rare substrate clones devoid of basic amino acids were also identified. Indeed one of these peptides was cleaved as free peptide, thus suggesting a broader range of WT-FSAP substrates than previously anticipated. 相似文献
4.
Xiaopeng Yue Yongjian Xu Nina Gou Hongkui Li 《Polymer-Plastics Technology and Engineering》2015,54(6):639-646
A long fatty side chain was introduced into the macromolecule of hydroxyethyl cellulose (HEC) via esterification reaction. The hydrophobicity of hydroxyethyl cellulose lauric acid ester (HECLAE) was enhanced in comparison with HEC. The obtained HECLAE was used as macromolecular coupling agent in poly (butylene succinate)/wood flour composites and exhibited a positive influence on improving the mechanical performance of composites. Besides, HECLAE plays a role as a hydrophobic agent in composites. A significant increase in storage modulus (E’) was observed upon the incorporation of treated wood flour. SEM images showed that the dispersion of treated wood flour in PBS matrix was improved. 相似文献
5.
6.
The microstructural aspects of compressive inelastic deformation in balsa wood are investigated with emphasis on the failure mode transition and its effects on energy dissipation characteristics. The architectural features as well as the composite character of cell wall ultrastructure are discussed in a framework to understand the complex interrelationship between microstructure and macroscopic behavior in this extremely lightweight cellular biocomposite. Based on this discussion and experimental results, it is concluded that the biomimetic approach may prove to be a viable strategy in designing composite structures with high specific energy absorption capacity. 相似文献
7.
8.
通过正交试验研究了各工艺量数以钢/铝合金液固相复合性能的影响,最佳工艺条件为铝合金液体温度790℃,钢板表面处理为酸洗+钢刷+5%的氟钛酸钾助焊剂,复合压力为39.2MPa,组织观察表面界面脆性化合物的形成是导致结合强度降低的一个重要因素。 相似文献
9.
彩色PDP用玻璃基板 总被引:4,自引:0,他引:4
本文讨论了彩色PDP现用钠钙玻璃的热稳定性,指出由于这种玻璃在热处理过程中易变形和收缩,因而不适合作大面积彩色PDP基板材料,介绍了彩色PDP基板玻璃的制造方法和特点。最后介绍了日本旭硝子公司和美国康宁公司各自为彩色PDP新开发的玻璃基板材料PD200和CS25。 相似文献
10.
晶体硅薄膜电池制备技术及研究现状 总被引:2,自引:0,他引:2
晶体硅薄膜太阳电池近些年来得到广泛的研究和初步的商业化探索。根据所采用的晶体硅薄膜沉积工艺中温度范围的不同,晶体硅薄膜电池研究可分为高温路线和低温路线两个不同发展方向。本文分别从这两个方向综述了目前国外晶体硅薄膜电池制备技术的最新进展,最新实验室研究结果。报导了晶体硅薄膜电池商业化进展状况,指出了晶体硅薄膜电池实现产业化必须解决的问题。 相似文献