全文获取类型
收费全文 | 70747篇 |
免费 | 15818篇 |
国内免费 | 6270篇 |
专业分类
化学 | 65549篇 |
晶体学 | 804篇 |
力学 | 2999篇 |
综合类 | 462篇 |
数学 | 6289篇 |
物理学 | 16732篇 |
出版年
2024年 | 87篇 |
2023年 | 822篇 |
2022年 | 967篇 |
2021年 | 1513篇 |
2020年 | 2812篇 |
2019年 | 3970篇 |
2018年 | 2290篇 |
2017年 | 1844篇 |
2016年 | 5083篇 |
2015年 | 5308篇 |
2014年 | 5488篇 |
2013年 | 6704篇 |
2012年 | 6235篇 |
2011年 | 5644篇 |
2010年 | 5159篇 |
2009年 | 4919篇 |
2008年 | 4527篇 |
2007年 | 3789篇 |
2006年 | 3321篇 |
2005年 | 3215篇 |
2004年 | 2804篇 |
2003年 | 2461篇 |
2002年 | 3229篇 |
2001年 | 2489篇 |
2000年 | 2104篇 |
1999年 | 1155篇 |
1998年 | 641篇 |
1997年 | 537篇 |
1996年 | 506篇 |
1995年 | 459篇 |
1994年 | 405篇 |
1993年 | 328篇 |
1992年 | 350篇 |
1991年 | 307篇 |
1990年 | 274篇 |
1989年 | 206篇 |
1988年 | 143篇 |
1987年 | 121篇 |
1986年 | 112篇 |
1985年 | 109篇 |
1984年 | 74篇 |
1983年 | 70篇 |
1982年 | 51篇 |
1981年 | 40篇 |
1980年 | 28篇 |
1979年 | 25篇 |
1978年 | 12篇 |
1977年 | 13篇 |
1975年 | 11篇 |
1974年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
1.
2.
Zhang Bing Yang Jie-qin Liu Ying Hu Bin Yang Yang Zhao Li Lu Qiang 《Cellulose (London, England)》2022,29(12):6565-6578
Cellulose - Heating is essential in various biomass pre-treatments and thermal conversion processes. It is of practical significance to study the characteristics of cellulose-lignin and... 相似文献
3.
Hua Saixiang Zhu Huichao Wang Xiao Wu Mingyuan Wu Qingyun Liu Jiuyi Yang Jianjun Zhang Jianan 《Cellulose (London, England)》2022,29(13):7465-7475
Cellulose - Ultraviolet (UV) protective cotton fabric is a convenient and reliable way to protect human body from sunlight. Herein, a polymerizable UV-absorber,... 相似文献
4.
5.
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
6.
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
7.
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
8.
9.
10.
Chemical versus Electrochemical Synthesis of Carbon Nano‐onion/Polypyrrole Composites for Supercapacitor Electrodes 下载免费PDF全文
Olena Mykhailiv Monika Imierska Martyna Petelczyc Prof. Dr. Luis Echegoyen Dr. Marta E. Plonska‐Brzezinska 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(15):5783-5793
The development of high‐surface‐area carbon electrodes with a defined pore size distribution and the incorporation of pseudo‐active materials to optimize the overall capacitance and conductivity without destroying the stability are at present important research areas. Composite electrodes of carbon nano‐onions (CNOs) and polypyrrole (Ppy) were fabricated to improve the specific capacitance of a supercapacitor. The carbon nanostructures were uniformly coated with Ppy by chemical polymerization or by electrochemical potentiostatic deposition to form homogenous composites or bilayers. The materials were characterized by transmission‐ and scanning electron microscopy, differential thermogravimetric analyses, FTIR spectroscopy, piezoelectric microgravimetry, and cyclic voltammetry. The composites show higher mechanical and electrochemical stabilities, with high specific capacitances of up to about 800 F g?1 for the CNOs/SDS/Ppy composites (chemical synthesis) and about 1300 F g?1 for the CNOs/Ppy bilayer (electrochemical deposition). 相似文献