全文获取类型
收费全文 | 254737篇 |
免费 | 40308篇 |
国内免费 | 29223篇 |
专业分类
化学 | 159331篇 |
晶体学 | 3152篇 |
力学 | 16364篇 |
综合类 | 955篇 |
数学 | 32135篇 |
物理学 | 112331篇 |
出版年
2023年 | 3120篇 |
2022年 | 4705篇 |
2021年 | 5555篇 |
2020年 | 6733篇 |
2019年 | 7029篇 |
2018年 | 7007篇 |
2017年 | 7200篇 |
2016年 | 9695篇 |
2015年 | 8462篇 |
2014年 | 10486篇 |
2013年 | 15017篇 |
2012年 | 16578篇 |
2011年 | 18454篇 |
2010年 | 17733篇 |
2009年 | 17672篇 |
2008年 | 13011篇 |
2007年 | 11734篇 |
2006年 | 10800篇 |
2005年 | 9802篇 |
2004年 | 9272篇 |
2003年 | 7771篇 |
2002年 | 7545篇 |
2001年 | 7301篇 |
2000年 | 5820篇 |
1999年 | 5833篇 |
1998年 | 5105篇 |
1997年 | 4729篇 |
1996年 | 5016篇 |
1995年 | 4938篇 |
1994年 | 4926篇 |
1993年 | 4737篇 |
1992年 | 4243篇 |
1991年 | 3851篇 |
1990年 | 3397篇 |
1989年 | 3281篇 |
1988年 | 3021篇 |
1987年 | 2281篇 |
1986年 | 2310篇 |
1985年 | 2000篇 |
1984年 | 2006篇 |
1983年 | 1276篇 |
1982年 | 1743篇 |
1981年 | 1471篇 |
1980年 | 1425篇 |
1979年 | 1305篇 |
1978年 | 1298篇 |
1977年 | 1357篇 |
1976年 | 1854篇 |
1973年 | 1216篇 |
1972年 | 1221篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Paired single residue‐transposed Lys‐N and Lys‐C digestions for label‐free identification of N‐terminal and C‐terminal MS/MS peptide product ions: ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry and tandem mass spectrometry for peptide de novo sequencing
下载免费PDF全文
![点击此处可从《Rapid communications in mass spectrometry : RCM》网站下载免费的PDF全文](/ch/ext_images/free.gif)
62.
Xinghua Li Yuqin Yang Junjie Miao Zhendong Yin Yijing Zhai Hongmei Shi Zengning Li 《Electrophoresis》2020,41(18-19):1584-1591
In the present research, field-amplified sample injection–CZE (FASI–CZE) coupled with a diode array detector was established to determine trace level sulfa antibiotic. Sulfathiazole, sulfadiazine, sulfamethazine, sulfadimethoxine, sulfamethoxazole, and sulfisoxazole were selected as analytes for the experiments. The background electrolyte solution consisted of 70.0 mmol/L borax and 60.0 mmol/L boric acid (including 10% methanol, pH 9.1). The plug was 2.5 mmol/L borax, which was injected into the capillary at a pressure of 0.5 psi for 5 s. Then the sample was injected into the capillary at an injection voltage of –10 kV for 20 s. The electrophoretic separation was carried out under a voltage of +19 kV. The capillary temperature was maintained at 20˚C throughout the analysis, and six sulfonamides were completely separated within 35 min. Compared with pressure injection-CZE, the sensitivity of FASI-CZE was increased by 6.25–10.0 times, and the LODs were reduced from 0.2–0.5 to 0.02–0.05 μg/mL. The method was applied to the determination of sulfonamides in river water and particulate matter samples. The recoveries were 78.59–106.59%. The intraday and interday precisions were 2.89–7.35% and 2.77–7.09%, respectively. This provides a simpler and faster method for the analysis of sulfa antibiotic residues in environmental samples. 相似文献
63.
Hongling Yu Heyong Wang Galia Pozina Chunyang Yin Xiao-Ke Liu Feng Gao 《Chemical science》2020,11(41):11338
Metal halide perovskites have demonstrated impressive properties for achieving efficient monochromatic light-emitting diodes. However, the development of white perovskite light-emitting diodes (PeLEDs) remains a big challenge. Here, we demonstrate a single-emissive-layer all-perovskite white PeLED using a mixed halide perovskite film as the emissive layer. The perovskite film consists of separated mixed halide perovskite phases with blue and red emissions, which are beneficial for suppressing halide anion exchange and preventing charge transfer. As a result, the white PeLED shows balanced white light emission with Commission Internationale de L''Eclairage coordinates of (0.33, 0.33). In addition, we find that the achievement of white light emission from mixed halide perovskites strongly depends on effective modulation of the halide salt precursors, especially lead bromide and benzamidine hydrochloride in our case. Our work provides very useful guidelines for realizing single-emissive-layer all-perovskite white PeLEDs based on mixed halide perovskites, which will spur the development of high-performance white PeLEDs.We demonstrated a single-emissive-layer all-perovskite white light-emitting diode based on a mixed halide perovskite film. 相似文献
64.
In the paper, the authors establish several integral representations for the generating functions of the large and little Schröder numbers and for the large and little Schröder numbers. 相似文献
65.
A Savitzky–Golay filtering for smoothing and peak search written in Python is presented in this paper alongside its applications in the list-mode digital data acquisition dual gamma–gamma coincidence bismuth germanate (BGO) detector. The study has demonstrated that the software provides a reliable and effective way to quantify trace amounts of 22Na and 7Be in aerosol samples collected at Resolute Bay, Canada with a critical limit of 3 mBq and 5 Bq respectively for a 20 h counting interval, which are believed to be the inherent limitations of the dual-BGO system.
相似文献66.
67.
68.
Knyazev A. A. Karyakin M. E. Krupin A. S. Galyametdinov Yu. G. 《Russian Journal of General Chemistry》2015,85(12):2806-2812
Russian Journal of General Chemistry - Hybrid liquid crystal systems with different ratios of the components have been prepared on the basis of 5,5′-di(heptadecyl)-2,2′-bipyridine... 相似文献
69.
Jing Zhihong Ling Baoping Yu Yang Qi Wei Zhang Shufang 《Journal of Sol-Gel Science and Technology》2015,73(1):112-117
Journal of Sol-Gel Science and Technology - A novel gas sensing material, La–Y co-doped TiO2 nanoparticles, was synthesized by sol–gel method and applied to detect organic pollutants... 相似文献
70.