全文获取类型
收费全文 | 16973篇 |
免费 | 3195篇 |
国内免费 | 2675篇 |
专业分类
化学 | 13561篇 |
晶体学 | 222篇 |
力学 | 1000篇 |
综合类 | 174篇 |
数学 | 2091篇 |
物理学 | 5795篇 |
出版年
2024年 | 33篇 |
2023年 | 294篇 |
2022年 | 450篇 |
2021年 | 602篇 |
2020年 | 710篇 |
2019年 | 820篇 |
2018年 | 645篇 |
2017年 | 584篇 |
2016年 | 898篇 |
2015年 | 983篇 |
2014年 | 1038篇 |
2013年 | 1305篇 |
2012年 | 1570篇 |
2011年 | 1541篇 |
2010年 | 1116篇 |
2009年 | 1099篇 |
2008年 | 1157篇 |
2007年 | 942篇 |
2006年 | 871篇 |
2005年 | 793篇 |
2004年 | 706篇 |
2003年 | 618篇 |
2002年 | 819篇 |
2001年 | 672篇 |
2000年 | 428篇 |
1999年 | 368篇 |
1998年 | 311篇 |
1997年 | 203篇 |
1996年 | 201篇 |
1995年 | 170篇 |
1994年 | 148篇 |
1993年 | 118篇 |
1992年 | 132篇 |
1991年 | 106篇 |
1990年 | 86篇 |
1989年 | 57篇 |
1988年 | 43篇 |
1987年 | 40篇 |
1986年 | 34篇 |
1985年 | 20篇 |
1984年 | 21篇 |
1983年 | 22篇 |
1982年 | 6篇 |
1981年 | 15篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1974年 | 5篇 |
1957年 | 4篇 |
1936年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
11.
We present the fabrication of core-shell-satellite Au@SiO2-Pt nanostructures and demonstrate that LSPR excitation of the core Au nanoparticle can induce plasmon coupling effect to initiate photocatalytic hydrogen generation from decomposition of formic acid. Further studies suggest that the plasmon coupling effect induces a strong local electric field between the Au core and Pt nanoparticles on the SiO2 shell, which enables creation of hot electrons on the non-plasmonic-active Pt nanoparticles to participate hydrogen evolution reaction on the Pt surface. In addition, small SiO2 shell thickness is required in order to obtain a strong plamon coupling effect and achieve efficient photocatalytic activities for hydrogen generation. 相似文献
12.
13.
14.
15.
16.
Ding Q. Yao M. Wu Sh. Zeng M. Xue N. Wu D. Xu J. 《Journal of Applied Spectroscopy》2022,89(4):712-718
Journal of Applied Spectroscopy - Based on partial least squares (PLS) analysis, the effects of different smoothing points and different preprocessing methods on the accuracy and precision of the... 相似文献
18.
19.
Hejia Hu Linlin Wu Mei Li Cun Xue Guangcheng Wang Siying Chen Yong Huang Lin Zheng Aimin Wang Yueting Li Zipeng Gong 《Biomedical chromatography : BMC》2020,34(1):e4714
Eucommia ulmoides Oliv. (E. ulmoides) is a valuable and nourishing medicinal herb in China that has been used in the treatment of hypertension. Given the fact that most traditional Chinese medicine is mainly used to treat disease, investigating the pharmacokinetics of traditional Chinese medicines in the pathological state is more useful than that in the normal state. However, the differences in the absorption kinetics of active ingredients of E. ulmoides extract between pathological and physiological conditions have not been reported. Therefore, in this study, the rat intestinal in situ circulatory perfusion model was used to investigate the differences in absorption kinetics of seven active ingredients of E. ulmoides extract in normal and spontaneously hypertensive rats, namely, genipinic acid, protocatechuic acid, neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, (+)-pinoresinol di-O-β-D -glucopyranoside and (+)-pinoresinol 4′-O-β-D -glucopyranoside. Our results indicate that the pathological state of spontaneous hypertension may change the absorption of active components of E. ulmoides extracts, and these findings may provide a reference for improving the rational use of E. ulmoides in the clinic. 相似文献
20.
Yaping Chen Dr. Kun Rui Prof. Jixin Zhu Prof. Shi Xue Dou Dr. Wenping Sun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(3):703-713
Developing clean and sustainable energies as alternatives to fossil fuels is in strong demand within modern society. The oxygen evolution reaction (OER) is the efficiency-limiting process in plenty of key renewable energy systems, such as electrochemical water splitting and rechargeable metal–air batteries. In this regard, ongoing efforts have been devoted to seeking high-performance electrocatalysts for enhanced energy conversion efficiency. Apart from traditional precious-metal-based catalysts, nickel-based compounds are the most promising earth-abundant OER catalysts, attracting ever-increasing interest due to high activity and stability. In this review, the recent progress on nickel-based oxide and (oxy)hydroxide composites for water oxidation catalysis in terms of materials design/synthesis and electrochemical performance is summarized. Some underlying mechanisms to profoundly understand the catalytic active sites are also highlighted. In addition, the future research trends and perspectives on the development of Ni-based OER electrocatalysts are discussed. 相似文献