全文获取类型
收费全文 | 98274篇 |
免费 | 8161篇 |
国内免费 | 4213篇 |
学科分类
工业技术 | 110648篇 |
出版年
2024年 | 222篇 |
2023年 | 1681篇 |
2022年 | 2597篇 |
2021年 | 4119篇 |
2020年 | 3256篇 |
2019年 | 2638篇 |
2018年 | 2887篇 |
2017年 | 3242篇 |
2016年 | 3010篇 |
2015年 | 4132篇 |
2014年 | 4912篇 |
2013年 | 5840篇 |
2012年 | 6331篇 |
2011年 | 6750篇 |
2010年 | 5784篇 |
2009年 | 5525篇 |
2008年 | 5371篇 |
2007年 | 5088篇 |
2006年 | 5425篇 |
2005年 | 4720篇 |
2004年 | 2996篇 |
2003年 | 2843篇 |
2002年 | 2661篇 |
2001年 | 2418篇 |
2000年 | 2336篇 |
1999年 | 2630篇 |
1998年 | 2081篇 |
1997年 | 1728篇 |
1996年 | 1690篇 |
1995年 | 1401篇 |
1994年 | 1147篇 |
1993年 | 732篇 |
1992年 | 641篇 |
1991年 | 436篇 |
1990年 | 347篇 |
1989年 | 294篇 |
1988年 | 219篇 |
1987年 | 140篇 |
1986年 | 112篇 |
1985年 | 68篇 |
1984年 | 45篇 |
1983年 | 40篇 |
1982年 | 41篇 |
1981年 | 26篇 |
1980年 | 24篇 |
1979年 | 16篇 |
1978年 | 1篇 |
1965年 | 1篇 |
1959年 | 3篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
31.
32.
Lin Haicheng Huang Wantong Zhao Kun Qiao Shuang Liu Zheng Wu Jian Chen Xi Ji Shuai-Hua 《Nano Research》2020,13(1):133-137
Nano Research - The isostructural and isoelectronic transition-metal-dichalcogenides 1T-TaS2 and 1T-TaSe2 are layered materials with intricate electronic structures. Combining the molecular beam... 相似文献
33.
Chengxiao Zhao Zupeng Chen Run Shi Xiaofei Yang Tierui Zhang 《Advanced materials (Deerfield Beach, Fla.)》2020,32(28):1907296
With the ambition of solving the challenges of the shortage of fossil fuels and their associated environmental pollution, visible-light-driven splitting of water into hydrogen and oxygen using semiconductor photocatalysts has emerged as a promising technology to provide environmentally friendly energy vectors. Among the current library of developed photocatalysts, organic conjugated polymers present unique advantages of sufficient light-absorption efficiency, excellent stability, tunable electronic properties, and economic applicability. As a class of rising photocatalysts, organic conjugated polymers offer high flexibility in tuning the framework of the backbone and porosity to fulfill the requirements for photocatalytic applications. In the past decade, significant progress has been made in visible-light-driven water splitting employing organic conjugated polymers. The recent development of the structural design principles of organic conjugated polymers (including linear, crosslinked, and supramolecular self-assembled polymers) toward efficient photocatalytic hydrogen evolution, oxygen evolution, and overall water splitting is described, thus providing a comprehensive reference for the field. Finally, current challenges and perspectives are also discussed. 相似文献
34.
Qi Yang Qilong Wu Yang Liu Shuiping Luo Xiaotong Wu Xixia Zhao Haiyuan Zou Baihua Long Wen Chen Yujia Liao Lanxi Li Pei Kang Shen Lele Duan Zewei Quan 《Advanced materials (Deerfield Beach, Fla.)》2020,32(36):2002822
Engineering novel Sn-based bimetallic materials could provide intriguing catalytic properties to boost the electrochemical CO2 reduction. Herein, the first synthesis of homogeneous Sn1−xBix alloy nanoparticles (x up to 0.20) with native Bi-doped amorphous SnOx shells for efficient CO2 reduction is reported. The Bi-SnOx nanoshells boost the production of formate with high Faradaic efficiencies (>90%) over a wide potential window (−0.67 to −0.92 V vs RHE) with low overpotentials, outperforming current tin oxide catalysts. The state-of-the-art Bi-SnOx nanoshells derived from Sn0.80Bi0.20 alloy nanoparticles exhibit a great partial current density of 74.6 mA cm−2 and high Faradaic efficiency of 95.8%. The detailed electrocatalytic analyses and corresponding density functional theory calculations simultaneously reveal that the incorporation of Bi atoms into Sn species facilitates formate production by suppressing the formation of H2 and CO. 相似文献
35.
37.
38.
结合目前国外钻机现状以及国际石油钻井市场对钻机的配套要求,分析指出我国目前陆地钻机存在的不足与差距,对我国钻机及其配套技术的发展提出建议。 相似文献
39.
Lü Qing Xu Bin Yu Yang Zhan Wei Zhao Yu Zheng Jun Ji Jian 《Bulletin of Engineering Geology and the Environment》2021,80(8):6513-6525
Bulletin of Engineering Geology and the Environment - Many uncertainties exist in pile-stabilized slopes which make their design substantially complicated. In this paper, a first-order reliability... 相似文献
40.