全文获取类型
收费全文 | 121686篇 |
免费 | 9917篇 |
国内免费 | 5468篇 |
专业分类
电工技术 | 6215篇 |
技术理论 | 1篇 |
综合类 | 9061篇 |
化学工业 | 21065篇 |
金属工艺 | 5913篇 |
机械仪表 | 7123篇 |
建筑科学 | 8770篇 |
矿业工程 | 2318篇 |
能源动力 | 4068篇 |
轻工业 | 9956篇 |
水利工程 | 2196篇 |
石油天然气 | 4890篇 |
武器工业 | 766篇 |
无线电 | 14323篇 |
一般工业技术 | 14896篇 |
冶金工业 | 5995篇 |
原子能技术 | 1560篇 |
自动化技术 | 17955篇 |
出版年
2024年 | 386篇 |
2023年 | 1505篇 |
2022年 | 2807篇 |
2021年 | 4254篇 |
2020年 | 3337篇 |
2019年 | 3084篇 |
2018年 | 3396篇 |
2017年 | 3627篇 |
2016年 | 3528篇 |
2015年 | 4186篇 |
2014年 | 5734篇 |
2013年 | 7535篇 |
2012年 | 7989篇 |
2011年 | 8493篇 |
2010年 | 7564篇 |
2009年 | 7416篇 |
2008年 | 7195篇 |
2007年 | 6912篇 |
2006年 | 6774篇 |
2005年 | 5717篇 |
2004年 | 4522篇 |
2003年 | 4055篇 |
2002年 | 4571篇 |
2001年 | 3960篇 |
2000年 | 3057篇 |
1999年 | 2547篇 |
1998年 | 2237篇 |
1997年 | 1804篇 |
1996年 | 1666篇 |
1995年 | 1373篇 |
1994年 | 1061篇 |
1993年 | 899篇 |
1992年 | 655篇 |
1991年 | 501篇 |
1990年 | 467篇 |
1989年 | 331篇 |
1988年 | 289篇 |
1987年 | 216篇 |
1986年 | 172篇 |
1985年 | 155篇 |
1984年 | 127篇 |
1983年 | 125篇 |
1982年 | 107篇 |
1981年 | 90篇 |
1980年 | 78篇 |
1979年 | 60篇 |
1978年 | 50篇 |
1977年 | 64篇 |
1976年 | 103篇 |
1974年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
1.
2.
Eivazzadeh-Keihan Reza Noruzi Ehsan Bahojb Mehrban Sarah Fattahi Aliabadi Hooman Aghamirza Moghim Karimi Meghdad Mohammadi Adibeh Maleki Ali Mahdavi Mohammad Larijani Bagher Shalan Ahmed Esmail 《Journal of Materials Science》2022,57(6):3855-3891
Journal of Materials Science - Chitosan is one of the natural cationic polymers with unique properties such as non-toxicity, biodegradability, biocompatibility, environmentally friendly that has... 相似文献
3.
Kelin Hu Feipeng Wang Yuyang Yan Hongcheng Liu Zijia Shen 《Ceramics International》2021,47(11):15228-15236
In this paper, a novel hybrid structure of Pd doped ZnO/SnO2 heterojunction nanofibers with hexagonal ZnO columns was one step synthesized from electrospun precursor nanofibers. Due to the synergistic effect of hexagonal ZnO, SnO2 and Pd, the structure exhibited excellent hydrogen (H2) gas sensing properties. At low-temperature of 120 °C, the response (Ra/Rg) to 100 ppm H2 gas exceeded 160, the response/recovery time was only 20 s and 6 s respectively and the limit of detection was only 0.5 ppm. Meanwhile, it also had good selectivity for H2 gas and excellent linearity. In addition, the materials were characterized by XRD, FESEM, HRTEM, XPS, and the synthesis mechanism and gas sensing mechanism were proposed. 相似文献
4.
Can Ercan S. Esra Safran Artuğ Türkmenoğlu Uğur Karabakal 《Journal of surfactants and detergents》2021,24(1):139-147
Garzan oil field is located at the south east of Turkey. It is a mature oil field and the reservoir is fractured carbonate reservoir. After producing about 1% original oil in place (OOIP) reservoir pressure started to decline. Waterflooding was started in order to support reservoir pressure and also to enhance oil production in 1960. Waterflooding improved the oil recovery but after years of flooding water breakthrough at the production wells was observed. This increased the water/oil ratio at the production wells. In order to enhance oil recovery again different techniques were investigated. Chemical enhanced oil recovery (EOR) methods are gaining attention all over the world for oil recovery. Surfactant injection is an effective way for interfacial tension (IFT) reduction and wettability reversal. In this study, 31 different types of chemicals were studied to specify the effects on oil production. This paper presents solubility of surfactants in brine, IFT and contact angle measurements, imbibition tests, and lastly core flooding experiments. Most of the chemicals were incompatible with Garzan formation water, which has high divalent ion concentration. In this case, the usage of 2-propanol as co-surfactant yielded successful results for stability of the selected chemical solutions. The results of the wettability test indicated that both tested cationic and anionic surfactants altered the wettability of the carbonate rock from oil-wet to intermediate-wet. The maximum oil recovery by imbibition test was reached when core was exposed 1-ethly ionic liquid after imbibition in formation water. Also, after core flooding test, it is concluded that considerable amount of oil can be recovered from Garzan reservoir by waterflooding alone if adverse effects of natural fractures could be eliminated. 相似文献
5.
Fan Deng-Ping Huang Ziling Zheng Peng Liu Hong Qin Xuebin Van Gool Luc 《国际自动化与计算杂志》2022,19(4):257-287
Machine Intelligence Research - This paper aims to conduct a comprehensive study on facial-sketch synthesis (FSS). However, due to the high cost of obtaining hand-drawn sketch datasets, there is a... 相似文献
6.
Hoseinzade Kimia Mousavi-Mashhadi Seyed Ali Shiri Ali 《Journal of Inorganic and Organometallic Polymers and Materials》2021,31(12):4648-4658
Journal of Inorganic and Organometallic Polymers and Materials - Immobility of copper on magnetic nanoparticles was performed using surface rectification of Fe3O4 with Agar. The magnetic... 相似文献
7.
Tourajizadeh Hami Yousefzadeh Mahdi Khalaji Ali Keymasi Bamdad Mahdi 《International Journal of Control, Automation and Systems》2022,20(5):1671-1681
International Journal of Control, Automation and Systems - In this paper, a new controllable simulator is proposed and modeled by which, experimental tests of the aircraft’s models can be... 相似文献
8.
Hong Sae Jin Park Nam Il Hwang Dae Keun Yi Tae Gyu Eum Hyang Lan 《Food science and biotechnology》2022,31(6):669-679
Food Science and Biotechnology - Various hilling materials (rice hulls, pine sawdust, and perlite) were compared to produce sprout vegetables using beach silvertop (Glehnia littoralis Fr. Schm. ex... 相似文献
9.
International Journal of Information Security - Machine learning techniques have been widely used and shown remarkable performance in various fields. Along with the widespread utilization of... 相似文献
10.
Catalysis Letters - In the present paper, an efficient Cu-catalyzed regioselective acylation of indoles with phenylglyoxals was developed which is the first example of indolyl diketones synthesis... 相似文献