全文获取类型
收费全文 | 613907篇 |
免费 | 9586篇 |
国内免费 | 2102篇 |
专业分类
电工技术 | 11532篇 |
综合类 | 681篇 |
化学工业 | 92079篇 |
金属工艺 | 23870篇 |
机械仪表 | 19228篇 |
建筑科学 | 14141篇 |
矿业工程 | 2961篇 |
能源动力 | 17346篇 |
轻工业 | 48226篇 |
水利工程 | 6097篇 |
石油天然气 | 10244篇 |
武器工业 | 43篇 |
无线电 | 75043篇 |
一般工业技术 | 122784篇 |
冶金工业 | 115844篇 |
原子能技术 | 12679篇 |
自动化技术 | 52797篇 |
出版年
2022年 | 3939篇 |
2021年 | 6197篇 |
2020年 | 4751篇 |
2019年 | 5705篇 |
2018年 | 9746篇 |
2017年 | 9686篇 |
2016年 | 10348篇 |
2015年 | 6826篇 |
2014年 | 10990篇 |
2013年 | 30269篇 |
2012年 | 17133篇 |
2011年 | 22757篇 |
2010年 | 18294篇 |
2009年 | 20440篇 |
2008年 | 21203篇 |
2007年 | 20873篇 |
2006年 | 18341篇 |
2005年 | 16353篇 |
2004年 | 15426篇 |
2003年 | 15432篇 |
2002年 | 14497篇 |
2001年 | 14547篇 |
2000年 | 13600篇 |
1999年 | 14368篇 |
1998年 | 37340篇 |
1997年 | 25811篇 |
1996年 | 19895篇 |
1995年 | 14811篇 |
1994年 | 13042篇 |
1993年 | 12950篇 |
1992年 | 9216篇 |
1991年 | 8800篇 |
1990年 | 8659篇 |
1989年 | 8199篇 |
1988年 | 7871篇 |
1987年 | 6829篇 |
1986年 | 6658篇 |
1985年 | 7428篇 |
1984年 | 6776篇 |
1983年 | 6293篇 |
1982年 | 5785篇 |
1981年 | 5817篇 |
1980年 | 5492篇 |
1979年 | 5225篇 |
1978年 | 5049篇 |
1977年 | 5970篇 |
1976年 | 8152篇 |
1975年 | 4334篇 |
1974年 | 4126篇 |
1973年 | 4168篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
11.
F.T. Munna Vidhya Selvanathan K. Sobayel Ghulam Muhammad Nilofar Asim Nowshad Amin Kamaruzzaman Sopian Md. Akhtaruzzaman 《Ceramics International》2021,47(8):11003-11009
In this study, dilute chemical bath deposition technique has been used to deposit CdZnS thin films on soda-lime glass substrates. The structural, morphological, optoelectronic properties of as-grown films have been investigated as a function of different Zn2+ precursor concentrations. The X-ray diffractogram of CdS thin-film reveals a peak corresponding to (002) plane with wurtzite structure, and the peak shift has been observed with the increase of the Zn2+ concentration upon formation of CdZnS thin film. From morphological studies, it has been revealed that the diluted chemical bath deposition technique provides homogeneous distribution of film on the substrate even at a lower concentration of Zn2+. Optical characterization has shown that the transparency of the film is influenced by Zn2+ concentration and when the Zn2+ concentration is varied from 0 M to 0.0256 M, bandgap values of resulting films range from 2.42 eV to 3.90 eV while. Furthermore, electrical properties have shown that with increasing zinc concentration the resistivity of the film increases. Finally, numerical simulation validates and suggests that CdZnS buffer layer with composition of 0.0032 M Zn2+ concentration would be a promising candidate in CIGS solar cell. 相似文献
12.
Combustion, Explosion, and Shock Waves - Results of a numerical study of mixing, ignition, and combustion of a cold hydrogen jet propagating along the lower wall of a channel parallel to a... 相似文献
13.
14.
Journal of Chemical Ecology - Biocontrol agents such as parasitic wasps use long-range volatiles and host-associated cues from lower trophic levels to find their hosts. However, this chemical... 相似文献
15.
Prof. Andrea Baier Dr. Anne Kokel Dr. William Horton Ewa Gizińska Dr. Garima Pandey Prof. Ryszard Szyszka Prof. Béla Török Prof. Marianna Török 《ChemMedChem》2021,16(12):1927-1932
A set of novel hydrazone derivatives were synthesized and analyzed for their biological activities. The compounds were tested for their inhibitory effect on the phosphorylating activity of the protein kinase CK2, and their antioxidant activity was also determined in three commonly used assays. The hydrazones were evaluated for their radical scavenging against the DPPH, ABTS and peroxyl radicals. Several compounds have been identified as good antioxidants as well as potent protein kinase CK2 inhibitors. Most hydrazones containing a 4-N(CH3)2 residue or perfluorinated phenyl rings showed high activity in the radical-scavenging assays and possess nanomolar IC50 values in the kinase assays. 相似文献
16.
Wireless Personal Communications - Despite its various benefits, the Mobile Ad-hoc Network (MANET) has a number of obstacles due to its mobility, unstable topology, energy efficiency, and other... 相似文献
17.
Telecommunication Systems - Energy saving in User Equipment (UE) is one of the important issues for limited sources of power in the device. It is critical for the UE to maximize its energy... 相似文献
18.
Seredin P. V. Radam Ali Obaid Goloshchapov D. L. Len’shin A. S. Buylov N. S. Barkov K. A. Nesterov D. N. Mizerov A. M. Timoshnev S. N. Nikitina E. V. Arsentyev I. N. Sharafidinov Sh. Kukushkin S. A. Kasatkin I. A. 《Semiconductors》2022,56(4):253-258
Semiconductors - Abstract—In our work, we carry out a structural-spectroscopic study of AlGaN/GaN epitaxial layers grown by molecular-beam epitaxy with nitrogen-plasma activation on a hybrid... 相似文献
19.
Boltar K. O. Burlakov I. D. Iakovleva N. I. Vlasov P. V. Lazarev P. S. 《Journal of Communications Technology and Electronics》2022,67(9):1175-1184
Journal of Communications Technology and Electronics - In recent years, there has been a rapid improvement in photonics products due to the use of multilayer heterostructures grown on the basis of... 相似文献
20.
Mobile Networks and Applications - Project MindCatcher is an art/research project which has the intention to explore the potential of interactive artistic environments for measuring and a better... 相似文献