全文获取类型
收费全文 | 405957篇 |
免费 | 5184篇 |
国内免费 | 1364篇 |
专业分类
电工技术 | 7610篇 |
综合类 | 318篇 |
化学工业 | 60347篇 |
金属工艺 | 16485篇 |
机械仪表 | 13524篇 |
建筑科学 | 8450篇 |
矿业工程 | 2174篇 |
能源动力 | 11588篇 |
轻工业 | 28667篇 |
水利工程 | 4282篇 |
石油天然气 | 7915篇 |
武器工业 | 17篇 |
无线电 | 49522篇 |
一般工业技术 | 83376篇 |
冶金工业 | 75670篇 |
原子能技术 | 9227篇 |
自动化技术 | 33333篇 |
出版年
2022年 | 2573篇 |
2021年 | 3918篇 |
2020年 | 2966篇 |
2019年 | 3835篇 |
2018年 | 6518篇 |
2017年 | 6508篇 |
2016年 | 6962篇 |
2015年 | 4366篇 |
2014年 | 7183篇 |
2013年 | 20122篇 |
2012年 | 11477篇 |
2011年 | 15373篇 |
2010年 | 12205篇 |
2009年 | 13796篇 |
2008年 | 14142篇 |
2007年 | 13873篇 |
2006年 | 12483篇 |
2005年 | 11156篇 |
2004年 | 10554篇 |
2003年 | 10472篇 |
2002年 | 9893篇 |
2001年 | 9789篇 |
2000年 | 9182篇 |
1999年 | 9576篇 |
1998年 | 24539篇 |
1997年 | 16850篇 |
1996年 | 12895篇 |
1995年 | 9599篇 |
1994年 | 8434篇 |
1993年 | 8453篇 |
1992年 | 6098篇 |
1991年 | 5760篇 |
1990年 | 5716篇 |
1989年 | 5356篇 |
1988年 | 5082篇 |
1987年 | 4452篇 |
1986年 | 4325篇 |
1985年 | 4854篇 |
1984年 | 4452篇 |
1983年 | 4023篇 |
1982年 | 3670篇 |
1981年 | 3752篇 |
1980年 | 3453篇 |
1979年 | 3343篇 |
1978年 | 3350篇 |
1977年 | 3777篇 |
1976年 | 4901篇 |
1975年 | 2868篇 |
1974年 | 2677篇 |
1973年 | 2747篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
A. Kathalingam S. Valanarasu Tansir Ahamad Saad M. Alshehri Hyun-Seok Kim 《Ceramics International》2021,47(6):7608-7616
Herein, we report the photosensing property of CdS thin films. CdS thin films were coated onto glass substrates via a spray pyrolysis method using different spray pressures. Prepared films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical and photoluminescence spectroscopy. XRD analysis demonstrated the growth of crystalline CdS films with crystallite sizes varying from 26 to 29 nm depending on the pressure. The SEM and EDAX analyses revealed nearly-stoichiometric CdS films with smooth surfaces and slight variation in grain morphology due to pressure changes. Optical measurements showed a direct bandgap varying from 2.37 eV to 2.42 eV due to pressure changes. A photodetector was also fabricated using the grown CdS films; the fabricated photodetector exhibited good performance depending on the spray pressure. A spray pressure of 1.5 GPa resulted in high photoresponsivity and external quantum efficiency. 相似文献
22.
Golubev N. V. Ignat’eva E. S. Maurus A. A. Ziyatdinova M. Z. Lopatina E. V. Lorenzi R. Paleari A. Sigaev V. N. 《Glass and Ceramics》2021,77(11-12):415-418
Glass and Ceramics - The influence of Al2O3 as an additive and the heat-treatment regime on the luminescence spectra of gallate glass-ceramics was investigated. It is shown that its luminescence... 相似文献
23.
Ava Kwong Cecilia Y. S. Ho Vivian Y. Shin Chun Hang Au Tsun Leung Chan Edmond S. K. Ma 《International journal of molecular sciences》2021,22(2)
The germline carrier of the BRCA1 pathogenic mutation has been well proven to confer an increased risk of breast and ovarian cancer. Despite BRCA1 biallelic pathogenic mutations being extremely rare, they have been reported to be embryonically lethal or to cause Fanconi anemia (FA). Here we describe a patient who was a 48-year-old female identified with biallelic pathogenic mutations of the BRCA1 gene, with no or very subtle FA-features. She was diagnosed with ovarian cancer and breast cancer at the ages of 43 and 44 and had a strong family history of breast and gynecological cancers. 相似文献
24.
Klimis?S.?NtalianisEmail author Anastasios?D.?Doulamis Nikolaos?D.?Doulamis Nikos?E.?Mastorakis Athanasios?S.?Drigas 《Journal of Signal Processing Systems》2015,80(2):153-161
In this paper, we present a novel memory access reduction scheme (MARS) for two-dimension fast cosine transform (2-D FCT). It targets programmable DSPs with high memory-access latency. It reduces the number of memory accesses by: 1) reducing the number of weighting factors and 2) combining butterflies in vector-radix 2-D FCT pruning diagram from two stages to one stage with an efficient structure. Hardware platform based on general purpose processor is used to verify the effectiveness of the proposed method for vector-radix 2-D FCT pruning implementation. Experimental results validate the benefits of the proposed method with reduced memory access, less clock cycle and fewer memory space compared with the conventional implementation. 相似文献
25.
26.
27.
28.
Gomes A. C. S. A. Costa L. C. Brito D. C. Frana R. J. Marques Mnica R. C. 《Polymer Bulletin》2020,77(4):1969-1981
Polymer Bulletin - In this study, we synthesized a new ion-imprinted polymer (IIP) based on introduction of amidoxime groups in acrylonitrile, complexation with Cd2+ ions and polymerization with... 相似文献
29.
Bankov S. E. Vesnik M. V. Kravchenko V. F. 《Journal of Communications Technology and Electronics》2020,65(4):398-405
Journal of Communications Technology and Electronics - Abstract—The article presents a rigorous numerical solution, using the Wiener–Hopf method, to the problem of plane wave... 相似文献
30.
Wireless Personal Communications - The rapid development of Information and Communication Technology and the growing number of devices connected to the Internet make the Internet of Things (IoT) as... 相似文献