全文获取类型
收费全文 | 560138篇 |
免费 | 20273篇 |
国内免费 | 10427篇 |
专业分类
化学 | 285222篇 |
晶体学 | 8501篇 |
力学 | 29848篇 |
综合类 | 517篇 |
数学 | 77024篇 |
物理学 | 189726篇 |
出版年
2022年 | 4215篇 |
2021年 | 5972篇 |
2020年 | 7055篇 |
2019年 | 7078篇 |
2018年 | 14850篇 |
2017年 | 15148篇 |
2016年 | 14516篇 |
2015年 | 9062篇 |
2014年 | 12050篇 |
2013年 | 24109篇 |
2012年 | 24689篇 |
2011年 | 34448篇 |
2010年 | 22752篇 |
2009年 | 22449篇 |
2008年 | 29048篇 |
2007年 | 31327篇 |
2006年 | 19049篇 |
2005年 | 22025篇 |
2004年 | 17438篇 |
2003年 | 15601篇 |
2002年 | 13631篇 |
2001年 | 13772篇 |
2000年 | 10994篇 |
1999年 | 9080篇 |
1998年 | 7527篇 |
1997年 | 7410篇 |
1996年 | 7199篇 |
1995年 | 6463篇 |
1994年 | 6142篇 |
1993年 | 5925篇 |
1992年 | 6193篇 |
1991年 | 6248篇 |
1990年 | 5841篇 |
1989年 | 5509篇 |
1988年 | 5529篇 |
1987年 | 5320篇 |
1986年 | 5021篇 |
1985年 | 6565篇 |
1984年 | 6843篇 |
1983年 | 5566篇 |
1982年 | 5898篇 |
1981年 | 5761篇 |
1980年 | 5488篇 |
1979年 | 5661篇 |
1978年 | 5832篇 |
1977年 | 5732篇 |
1976年 | 5862篇 |
1975年 | 5403篇 |
1974年 | 5368篇 |
1973年 | 5605篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Kuz’mina L. G. Navasardyan M. A. Kalle P. Bezzubov S. I. 《Crystallography Reports》2021,66(3):420-423
Crystallography Reports - The crystal and molecular structures of Cl–C6H4–O–C16H33 (I) have been studied, and its differential scanning calorimetry (DSC) study is performed.... 相似文献
42.
43.
Journal of Applied Mechanics and Technical Physics - A refined model of viscoelastic-plastic deformation of flexible plates with spatial reinforcement structures has been developed. Strains of the... 相似文献
44.
Crystallography Reports - The recombinant С-terminal fragment of myomesin-2 was purified to a homogeneous state. The crystallization conditions for the С-terminal fragment of myomesin-2... 相似文献
45.
Doklady Physics - This work is devoted to analysis and generalization of the kinetic criteria of vitrification using the model of delocalized atoms. The generalized criterion of a... 相似文献
46.
47.
48.
Journal of Experimental and Theoretical Physics - The studies of the topological properties of systems have recently been extended due to a new concept of higher-order topological insulators and... 相似文献
49.
Dr. Ruijuan Yao Prof. Di Liu Dr. Huihui Wan Dr. Yongqiang Mei Jiahui Wang Dr. Rui Cai Dr. Huimin Zhang Dr. Yuzhen Zhao Dr. Zemin He 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(71):e202202269
By linking the carbazole unit to the nitrogen atom of acridone through phenyl or pyridyl, two compounds, named 10-(4-(9H-carbazol-9-yl)phenyl)acridin-9(10H)-one (AC-Ph-Cz) and 10-(5-(9H-carbazol-9-yl)pyridin-2-yl)acridin-9(10H)-one (AC-Py-Cz) were designed and synthesized. These two materials, characterized with highly twisted and rigid structure, good thermal stability, and balanced carrier-transporting properties, were employed as host materials for green phosphorescent and thermally activated delayed fluorescent organic light-emitting diodes (OLEDs). The carbazole group, despite its small contribution to the highest occupied molecular orbitals (HOMOs) of these two materials, plays an essential role as an intramolecular host in energy delivering and improving the hole transporting ability of these two hosts. The incorporation of the electron-deficient pyridyl group as a linking group slightly improves the electron transporting capability of AC-Py-Cz. The green phosphorescent OLED (PhOLED) based on AC-Py-Cz exhibited excellent device performance with a turn-on voltage of 2.5 V, a maximum power efficiency and an external quantum efficiency (ηext) of 89.8 lm W−1 and 25.2 %, respectively, benefitting from the better charge-balancing ability of AC-Py-Cz host due to the presence of the pyridyl bridge. More importantly, all the devices based on these two hosts showed low efficiency roll-off at high brightness due to the suppressed non-radiative transition in the emitting layer. In particular, the AC-Py-Cz-hosted green PhOLED exhibited an efficiency roll-off of 1.6 % from the maximum next at a high brightness of 1000 cd m−2 and a roll-off of 15.9 % at an extremely high brightness of 10000 cd m−2. This study manifests that acridone-based host materials have great potential in fabricating OLEDs with low efficiency roll-off. 相似文献
50.
Liu Jingze Fei Qingguo Wu Shaoqing Tang Zhenhuan Zhang Dahai 《Nonlinear dynamics》2021,106(3):1869-1890
Nonlinear Dynamics - Rolling bearing and squeeze film damper will introduce structural nonlinearity into the dynamic model of aeroengine. Rubbing will occur due to the clearance reduction design of... 相似文献