全文获取类型
收费全文 | 128666篇 |
免费 | 17994篇 |
国内免费 | 10851篇 |
专业分类
化学 | 61458篇 |
晶体学 | 916篇 |
力学 | 5746篇 |
综合类 | 512篇 |
数学 | 10090篇 |
物理学 | 37230篇 |
综合类 | 41559篇 |
出版年
2024年 | 582篇 |
2023年 | 2645篇 |
2022年 | 4024篇 |
2021年 | 4273篇 |
2020年 | 4393篇 |
2019年 | 3679篇 |
2018年 | 3507篇 |
2017年 | 3260篇 |
2016年 | 5014篇 |
2015年 | 5133篇 |
2014年 | 6592篇 |
2013年 | 7912篇 |
2012年 | 9334篇 |
2011年 | 9567篇 |
2010年 | 6743篇 |
2009年 | 6794篇 |
2008年 | 7354篇 |
2007年 | 6650篇 |
2006年 | 6024篇 |
2005年 | 5192篇 |
2004年 | 3996篇 |
2003年 | 3170篇 |
2002年 | 3039篇 |
2001年 | 2826篇 |
2000年 | 2749篇 |
1999年 | 4061篇 |
1998年 | 3708篇 |
1997年 | 3689篇 |
1996年 | 3544篇 |
1995年 | 3091篇 |
1994年 | 2684篇 |
1993年 | 2320篇 |
1992年 | 2037篇 |
1991年 | 1840篇 |
1990年 | 1557篇 |
1989年 | 1321篇 |
1988年 | 1048篇 |
1987年 | 734篇 |
1986年 | 543篇 |
1985年 | 342篇 |
1984年 | 166篇 |
1983年 | 123篇 |
1982年 | 101篇 |
1981年 | 58篇 |
1980年 | 42篇 |
1979年 | 15篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1957年 | 31篇 |
1922年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Dr. Yong-Sheng Wei Dr. Liming Sun Miao Wang Dr. Jinhua Hong Dr. Lianli Zou Hongwen Liu Dr. Yu Wang Dr. Mei Zhang Dr. Zheng Liu Prof. Yinwei Li Prof. Satoshi Horike Prof. Kazu Suenaga Prof. Qiang Xu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(37):16147-16156
Understanding the thermal aggregation behavior of metal atoms is important for the synthesis of supported metal clusters. Here, derived from a metal–organic framework encapsulating a trinuclear FeIII2FeII complex (denoted as Fe3) within the channels, a well-defined nitrogen-doped carbon layer is fabricated as an ideal support for stabilizing the generated iron nanoclusters. Atomic replacement of FeII by other metal(II) ions (e.g., ZnII/CoII) via synthesizing isostructural trinuclear-complex precursors (Fe2Zn/Fe2Co), namely the “heteroatom modulator approach”, is inhibiting the aggregation of Fe atoms toward nanoclusters with formation of a stable iron dimer in an optimal metal–nitrogen moiety, clearly identified by direct transmission electron microscopy and X-ray absorption fine structure analysis. The supported iron dimer, serving as cooperative metal–metal site, acts as efficient oxygen evolution catalyst. Our findings offer an atomic insight to guide the future design of ultrasmall metal clusters bearing outstanding catalytic capabilities. 相似文献
32.
33.
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
34.
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35.
36.
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
37.
38.
Nonlinear Dynamics - With an increasing number of people sharing feelings and opinions online, the online platforms have become one of the most important channels for public opinion dissemination.... 相似文献
39.
采用变分方法和临界点理论研究一个时标轴上二阶Dirichlet边值问题弱解的存在性. 相似文献
40.
Richiro Ushimaru Zhang Chen Houyuan Zhao Po-hsun Fan Prof. Dr. Hung-wen Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(9):3586-3590
Albomycin δ2 is a sulfur-containing sideromycin natural product that shows potent antibacterial activity against clinically important pathogens. The l -serine-thioheptose dipeptide partial structure, known as SB-217452, has been found to be the active seryl-tRNA synthetase inhibitor component of albomycin δ2. Herein, it is demonstrated that AbmF catalyzes condensation between the 6′-amino-4′-thionucleoside with the d -ribo configuration and seryl-adenylate supplied by the serine adenylation activity of AbmK. Formation of the dipeptide is followed by C3′-epimerization to produce SB-217452 with the d -xylo configuration, which is catalyzed by the radical S-adenosyl-l -methionine enzyme AbmJ. Gene deletion suggests that AbmC is involved in peptide assembly linking SB-217452 with the siderophore moiety. This study establishes how the albomycin biosynthetic machinery generates its antimicrobial component SB-217452. 相似文献