全文获取类型
收费全文 | 21151篇 |
免费 | 3926篇 |
国内免费 | 3033篇 |
专业分类
化学 | 15803篇 |
晶体学 | 345篇 |
力学 | 1265篇 |
综合类 | 217篇 |
数学 | 2295篇 |
物理学 | 8185篇 |
出版年
2024年 | 31篇 |
2023年 | 505篇 |
2022年 | 659篇 |
2021年 | 837篇 |
2020年 | 1083篇 |
2019年 | 1075篇 |
2018年 | 894篇 |
2017年 | 892篇 |
2016年 | 1162篇 |
2015年 | 1217篇 |
2014年 | 1423篇 |
2013年 | 1749篇 |
2012年 | 2076篇 |
2011年 | 2046篇 |
2010年 | 1406篇 |
2009年 | 1458篇 |
2008年 | 1539篇 |
2007年 | 1300篇 |
2006年 | 1202篇 |
2005年 | 957篇 |
2004年 | 745篇 |
2003年 | 513篇 |
2002年 | 514篇 |
2001年 | 450篇 |
2000年 | 350篇 |
1999年 | 322篇 |
1998年 | 248篇 |
1997年 | 221篇 |
1996年 | 181篇 |
1995年 | 172篇 |
1994年 | 141篇 |
1993年 | 132篇 |
1992年 | 106篇 |
1991年 | 103篇 |
1990年 | 74篇 |
1989年 | 47篇 |
1988年 | 47篇 |
1987年 | 39篇 |
1986年 | 32篇 |
1985年 | 37篇 |
1984年 | 19篇 |
1983年 | 23篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1977年 | 7篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1971年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Rui Feng Zi-Ying Li Zhao-Quan Yao Zi-Ang Guo Yi-Nan Zhang Hao-Xiang Sun Wei Li Xian-He Bu 《中国科学:化学(英文版)》2022,65(1):128-134
The rational designability and chemical tunability of metal-organic frameworks(MOFs)are enabling tributes to efficaciously enhance their room temperature phosphorescence(RTP)performance.A family of stable anionic MOFs,[Zn2(4,5-ImDC)2]M2(NKU-132,M=(CH3)2NH2or(CH2CH3)2NH2),featuring significant RTP have been synthesized.By rational cation selection and in-situ replacement from dimethylammonium to diethylammonium,the phosphorescence lifetime is increased from 30.88 to126.3 ms,along with less sensitivity to air.This work provides an anti-quenching and lifetime tuning example for RTP-MOFmaterials via facile host-guest chemistry. 相似文献
2.
Hierarchical motion planning at the acceleration level based on task priority matrix for space robot
Nonlinear Dynamics - A capacitive micromachined ultrasonic transducer (CMUT) due to many benefits is being considered as an imaging and therapeutic technology recently. The critical challenge is to... 相似文献
3.
4.
Journal of Algebraic Combinatorics - In this paper, we demonstrate a method for calculating the production matrices for the Euler-genus polynomials of H-linear families of graphs. Particularly, for... 相似文献
5.
Yang Shaoming Deng Kaiqiang Shao Shan Zhang Jian Peng Jiaxi Fang Zhili Xu Wenyuan 《Journal of Solid State Electrochemistry》2022,26(3):821-830
Journal of Solid State Electrochemistry - A molecularly imprinted photoelectrochemical (PEC) cathodic sensor was developed for the detection of bovine serum albumin (BSA). The PEC sensor was... 相似文献
6.
Chen Fenge Li Bing Peng Xingchun 《Methodology and Computing in Applied Probability》2022,24(2):635-659
Methodology and Computing in Applied Probability - This paper is devoted to the study of an optimal investment and risk control problem for an insurer. The risky asset process and the insurance... 相似文献
7.
We propose a lumped element Josephson parametric amplifier with vacuum-gap-based capacitor.The capacitor is made of quasi-floating aluminum pad and on-chip ground.We take a fabrication process compatible with air-bridge technology,which makes our design adaptable for future on-chip integrated quantum computing system.Further engineering the input impedance,we obtain a gain above 20 dB over 162-MHz bandwidth,along with a quasi quantum-limit noise performance.This work should facilitate the development of quantum information processing and integrated superconducting circuit design. 相似文献
8.
Oliveira M. Rosário Azeitona Margarida Pacheco António Valadas Rui 《Advances in Data Analysis and Classification》2022,16(3):491-520
Advances in Data Analysis and Classification - Symbolic Data Analysis (SDA) is a relatively new field of statistics that extends conventional data analysis by taking into account intrinsic data... 相似文献
10.
The placement optimization of piezoelectric actuators and active vibration control of a membrane structure are studied in this paper. The classical linear quadratic regulator controllers are designed to suppress the unwanted vibration. Simulation results indicate that the optimal locations of piezoelectric actuators are affected deeply by the additional mass and stiffness of actuators, the computational efficiency of particle swarm optimizer is higher than that of genetic algorithm for this particular problem, and the control performance of optimally placed actuators is better than that of non-optimally placed actuators. 相似文献