全文获取类型
收费全文 | 208843篇 |
免费 | 3610篇 |
国内免费 | 1486篇 |
专业分类
化学 | 105600篇 |
晶体学 | 2711篇 |
力学 | 9921篇 |
综合类 | 70篇 |
数学 | 23499篇 |
物理学 | 72138篇 |
出版年
2021年 | 1860篇 |
2020年 | 2128篇 |
2019年 | 2310篇 |
2018年 | 2980篇 |
2017年 | 2875篇 |
2016年 | 4174篇 |
2015年 | 2706篇 |
2014年 | 4057篇 |
2013年 | 9706篇 |
2012年 | 7954篇 |
2011年 | 9534篇 |
2010年 | 6581篇 |
2009年 | 6427篇 |
2008年 | 8512篇 |
2007年 | 8544篇 |
2006年 | 8223篇 |
2005年 | 7253篇 |
2004年 | 6725篇 |
2003年 | 5894篇 |
2002年 | 5452篇 |
2001年 | 6395篇 |
2000年 | 4816篇 |
1999年 | 3697篇 |
1998年 | 2935篇 |
1997年 | 3000篇 |
1996年 | 2720篇 |
1995年 | 2684篇 |
1994年 | 2515篇 |
1993年 | 2372篇 |
1992年 | 2709篇 |
1991年 | 2657篇 |
1990年 | 2594篇 |
1989年 | 2384篇 |
1988年 | 2431篇 |
1987年 | 2417篇 |
1986年 | 2254篇 |
1985年 | 2934篇 |
1984年 | 3196篇 |
1983年 | 2603篇 |
1982年 | 2772篇 |
1981年 | 2718篇 |
1980年 | 2599篇 |
1979年 | 2697篇 |
1978年 | 2787篇 |
1977年 | 2803篇 |
1976年 | 2864篇 |
1975年 | 2650篇 |
1974年 | 2625篇 |
1973年 | 2755篇 |
1972年 | 1743篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Starodub T. N. Fenske D. Fuhr O. Miskiewicz S. Kazheva O. N. Starodub V. A. 《Crystallography Reports》2021,66(3):408-412
Crystallography Reports - Anion-radical salt of 7,7,8,8-tetracyanoquinodimethane with N-methyl-2,2'-dipyridyl cation is synthesized. Its composition is determined using electron spectroscopy... 相似文献
62.
Theoretical and Mathematical Physics - Dynamic systems acting on the plane and possessing the Wada property have been observed. There exist only two topological types, symmetric and antisymmetric,... 相似文献
63.
64.
Mathematical Notes - 相似文献
65.
Differential Equations - We consider the direct initial–boundary value problem for the equation of transverse vibrations of a homogeneous beam freely supported at the ends and study the... 相似文献
66.
Mirgorodskaya A. B. Kushnazarova R. A. Kuznetsov D. M. Tyryshkina A. A. Zakharova L. Ya. 《Kinetics and Catalysis》2022,63(3):261-269
Kinetics and Catalysis - The aggregation behavior of new cationic hexadecyl surfactants with one or two alkylcarbamate fragments in the head group in water was studied using conductometry,... 相似文献
67.
Ibotov Sh. Kh. Yuldasheva N. K. Mukarramov N. I. Zakirova R. P. Gusakova S. D. 《Chemistry of Natural Compounds》2022,58(4):728-731
Chemistry of Natural Compounds - 相似文献
68.
Dr. Swati Deswal Rishukumar Panday Dr. Dipti R. Naphade Prashant Dixit Dr. Balu Praveenkumar Dr. Jan K. Zaręba Prof. Dr. Thomas D. Anthopoulos Prof. Dr. Satishchandra Ogale Prof. Dr. Ramamoorthy Boomishankar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(33):e202200751
Bismuth containing hybrid molecular ferroelectrics are receiving tremendous attention in recent years owing to their stable and non-toxic composition. However, these perovskite-like structures are primarily limited to ammonium cations. Herein, we report a new phosphonium based discrete perovskite-like hybrid ferroelectric with a formula [Me(Ph)3P]3[Bi2Br9] ( MTPBB ) and its mechanical energy harvesting capability. The Polarization-Electric field (P-E) measurements resulted in a well-defined ferroelectric hysteresis loop with a remnant polarization value of 2.1 μC cm−2. Piezoresponse force microscopy experiments enabled visualization of the ferroelectric domain structure and evaluation of the piezoelectric strain coefficient (d33) for an MTPBB single crystal and thin film sample. Furthermore, flexible devices incorporating MTPBB in polydimethylsiloxane (PDMS) matrix at various concentrations were fabricated and explored for their mechanical energy harvesting properties. The champion device with 20 wt % of MTPBB in PDMS rendered a maximum peak-to-peak open-circuit voltage of 22.9 V and a maximum power density of 7 μW cm−2 at an optimal load of 4 MΩ. Moreover, the potential of MTPBB -based devices in low power electronics was demonstrated by storing the harvested energy in various electrolytic capacitors. 相似文献
69.
Smirnova T. D. Zhelobitskaya E. A. Danilina T. G. 《Journal of Analytical Chemistry》2022,77(8):1000-1004
Journal of Analytical Chemistry - Silver nanoparticles modified with Eu3+ ions increase the intensity of the fluorescence signal by a factor of 125 in an analytical system containing doxycycline as... 相似文献
70.
Gaineev A. M. Galkina I. V. Davletshin R. R. Davletshina N. V. Kuznetsov N. O. Grishaev D. Yu. Shulayeva M. P. Pozdeev O. K. 《Russian Journal of General Chemistry》2022,92(7):1208-1213
Russian Journal of General Chemistry - Aminophosphabetaines, i.e., isobutyl {[alkyl(dimethyl)ammonio]methyl}phosphonates with higher alkyl substituents at the nitrogen atom, were obtained by a... 相似文献