全文获取类型
收费全文 | 138667篇 |
免费 | 25455篇 |
国内免费 | 36530篇 |
专业分类
化学 | 103452篇 |
晶体学 | 4145篇 |
力学 | 9029篇 |
综合类 | 3751篇 |
数学 | 20827篇 |
物理学 | 59448篇 |
出版年
2024年 | 291篇 |
2023年 | 1750篇 |
2022年 | 4101篇 |
2021年 | 4543篇 |
2020年 | 4959篇 |
2019年 | 4952篇 |
2018年 | 4396篇 |
2017年 | 5455篇 |
2016年 | 5547篇 |
2015年 | 6879篇 |
2014年 | 8314篇 |
2013年 | 10927篇 |
2012年 | 11942篇 |
2011年 | 12725篇 |
2010年 | 11044篇 |
2009年 | 11058篇 |
2008年 | 12277篇 |
2007年 | 11268篇 |
2006年 | 10721篇 |
2005年 | 9048篇 |
2004年 | 7025篇 |
2003年 | 5540篇 |
2002年 | 5633篇 |
2001年 | 5315篇 |
2000年 | 4981篇 |
1999年 | 3347篇 |
1998年 | 2025篇 |
1997年 | 1784篇 |
1996年 | 1640篇 |
1995年 | 1485篇 |
1994年 | 1410篇 |
1993年 | 1284篇 |
1992年 | 1174篇 |
1991年 | 844篇 |
1990年 | 752篇 |
1989年 | 764篇 |
1988年 | 583篇 |
1987年 | 491篇 |
1986年 | 432篇 |
1985年 | 343篇 |
1984年 | 318篇 |
1983年 | 245篇 |
1982年 | 194篇 |
1981年 | 162篇 |
1980年 | 127篇 |
1979年 | 122篇 |
1978年 | 54篇 |
1977年 | 38篇 |
1965年 | 59篇 |
1959年 | 32篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Hu Duo-Duo Gao Qian Dai Jing-Cheng Cui Ru Li Yuan-Bo Li Yuan-Ming Zhou Xiao-Guo Bian Kang-Jie Wu Bing-Bing Zhang Kai-Fan Wang Xi-Sheng Li Yan 《中国科学:化学(英文版)》2022,65(4):753-761
Science China Chemistry - A light-induced, nickel-catalyzed three-component arylsulfonation of 1,3-enynes in the absence of photocatalyst is reported. This methodology exhibited mild conditions,... 相似文献
22.
Journal of Visualization - The increasing availability of spatiotemporal data provides unprecedented opportunities for understanding the structure of an urban area in terms of people’s... 相似文献
23.
International Journal of Theoretical Physics - The Majorana representation, which provides an intuitive way to represent the quantum state by stars on the Bloch sphere, has drawn considerable... 相似文献
24.
The chiral phase transition and equation of state are studied within a novel self-consistent mean-field approximation of the two-flavor Nambu-Jona-Lasinio model. In this newly developed model, modifications to the chemical μ and chiral chemical \begin{document}$\mu_5$\end{document} ![]()
![]()
potentials are naturally included by introducing vector and axial-vector channels from Fierz-transformed Lagrangian to the standard Lagrangian. In the proper-time scheme, the chiral phase transition is a crossover in the \begin{document}$T-\mu$\end{document} ![]()
![]()
plane. However, when \begin{document}$\mu_5$\end{document} ![]()
![]()
is incorporated, our study demonstrates that a first order phase transition may emerge. Furthermore, the chiral imbalance will soften the equation of state of quark matter. The mass-radius relationship and tidal deformability of quark stars are calculated. The maximum mass and radius decrease as \begin{document}$\mu_5$\end{document} ![]()
![]()
increases. Our study also indicates that the vector and axial-vector channels exhibit an opposite influence on the equation of state. 相似文献
25.
Herein, we successfully construct the 3D biocompatible graphene through crosslinking 2D graphene nanosheet onto carbon fiber paper with poly(diallyldimethylammonium chloride) (PDDA) as anode of the alcohol biofuel cell. Compared with the bioanode without 3D graphene, the current density and output power of PDDA-graphene-ADH bioanode is increased by 23 % and 41 % at a high concentration of ethanol at pH 8.9, suggesting the stabilization role of graphene in enzyme loading. The study provides us a deep analysis on structures and performances of the bioanode incl. electrochemistry, X-ray photoelectron spectra, and atomic force microscopy images, which is significant to develop the new methods to construct 3D porous electrodes in energy conversion device. 相似文献
26.
Sun Guo-Hua Dong Qian Bezerra V. B. Dong Shi-Hai 《Journal of mathematical chemistry》2022,60(4):605-612
Journal of Mathematical Chemistry - The analytical solutions of an asymmetric double well potential $$V(x)=a\, x^2-b\, x^3+c\, x^4$$ are found to be a triconfluent Heun function $$H_{T}(\alpha ,... 相似文献
28.
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
29.
Ruirui Xu Kun Wang Haoying Liu Prof. Dr. Weijun Tang Dr. Huaming Sun Prof. Dr. Dong Xue Prof. Dr. Jianliang Xiao Prof. Dr. Chao Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22143-22148
A ruthenium-catalyzed formal anti-Markovnikov hydroamination of allylic alcohols for the synthesis of chiral γ-amino alcohols is presented. Proceeding via an asymmetric hydrogen-borrowing process, the catalysis allows racemic secondary allylic alcohols to react with various amines, affording enantiomerically enriched chiral γ-amino alcohols with broad substrate scope and excellent enantioselectivities (68 examples, up to >99 % ee). 相似文献
30.
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)