全文获取类型
收费全文 | 96177篇 |
免费 | 18683篇 |
国内免费 | 8724篇 |
专业分类
化学 | 82021篇 |
晶体学 | 1152篇 |
力学 | 4293篇 |
综合类 | 536篇 |
数学 | 9822篇 |
物理学 | 25760篇 |
出版年
2024年 | 142篇 |
2023年 | 1194篇 |
2022年 | 1686篇 |
2021年 | 2101篇 |
2020年 | 3372篇 |
2019年 | 4495篇 |
2018年 | 2888篇 |
2017年 | 2502篇 |
2016年 | 5825篇 |
2015年 | 5944篇 |
2014年 | 6466篇 |
2013年 | 8076篇 |
2012年 | 8024篇 |
2011年 | 7741篇 |
2010年 | 6624篇 |
2009年 | 6514篇 |
2008年 | 6472篇 |
2007年 | 5455篇 |
2006年 | 4936篇 |
2005年 | 4442篇 |
2004年 | 3644篇 |
2003年 | 3153篇 |
2002年 | 3746篇 |
2001年 | 2819篇 |
2000年 | 2641篇 |
1999年 | 1743篇 |
1998年 | 1261篇 |
1997年 | 1137篇 |
1996年 | 1162篇 |
1995年 | 1019篇 |
1994年 | 917篇 |
1993年 | 787篇 |
1992年 | 754篇 |
1991年 | 615篇 |
1990年 | 536篇 |
1989年 | 439篇 |
1988年 | 367篇 |
1987年 | 310篇 |
1986年 | 300篇 |
1985年 | 304篇 |
1984年 | 210篇 |
1983年 | 135篇 |
1982年 | 130篇 |
1981年 | 91篇 |
1980年 | 67篇 |
1979年 | 68篇 |
1978年 | 40篇 |
1976年 | 37篇 |
1974年 | 40篇 |
1973年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Miao Xiu-feng Xu Yao-qun Yao Feng-ge 《International Journal of Theoretical Physics》2021,60(7):2604-2612
International Journal of Theoretical Physics - This paper mainly studied the observer design of Lipschitz stochastic discrete system. For the first time, generalized Lipschitz conditions are... 相似文献
12.
Nonlinear Dynamics - The classical Kuramoto model serves as a useful tool for studying synchronization transitions in coupled oscillators that is limited to the sinusoidal and pairwise... 相似文献
13.
Li Y. Shi W. H. Dong L. M. Xu S. X. Huang H. J. Yin J. R. 《Journal of Applied Spectroscopy》2022,89(3):534-541
Journal of Applied Spectroscopy - Sr3B2O6:Dy3+, Eu3+ single-matrix white-light-emitting materials are prepared using the high-temperature solid-state method. The microstructure, emission spectrum,... 相似文献
14.
Yi-Tong Xu Tian-Yang Zhang Zheng Li Xiang-Nan Liu Yuan-Cheng Zhu Wei-Wei Zhao Hong-Yuan Chen Jing-Juan Xu 《Electroanalysis》2022,34(6):947-955
Photoelectrochemical (PEC) cytosensors, a combination of the PEC process and the living-cell assay, have emerged as a powerful tool in the analytical and biological science. This mini review provides a brief introduction of this arena and summaries the key steps about the development of PEC cytosensors with representative examples, followed by future prospects based on our own opinions. 相似文献
15.
Xu Mengtao Li Changyou Sun Yang Yang Tianzhi Zhang Hongzhuang Liu Zhendong Liu Haiyang Li Zhenyuan Zhang Yimin 《Nonlinear dynamics》2021,105(4):3061-3092
Nonlinear Dynamics - Investigation of the dynamic characteristics of linear guideway is essential for enhancing structural performance of machine tools. However, few mechanical models are... 相似文献
16.
Mathematical Programming - In the general equilibrium with incomplete asset markets (GEI) model, the excess demand functions are typically not continuous at the prices for which the assets have... 相似文献
17.
Interactions of the vector breathers for the coupled Hirota system with $$4\times 4$$ 4 × 4 Lax pair
Nonlinear Dynamics - In this paper, we investigate the interactions of the vector breathers for the coupled Hirota system with $$4\times 4$$ Lax pair. Firstly, we give the first-order breather... 相似文献
18.
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
19.
For an integer , a graph is -hamiltonian if for any vertex subset with , is hamiltonian, and is -hamiltonian connected if for any vertex subset with , is hamiltonian connected. Thomassen in 1984 conjectured that every 4-connected line graph is hamiltonian (see Thomassen, 1986), and Ku?zel and Xiong in 2004 conjectured that every 4-connected line graph is hamiltonian connected (see Ryjá?ek and Vrána, 2011). In Broersma and Veldman (1987), Broersma and Veldman raised the characterization problem of -hamiltonian line graphs. In Lai and Shao (2013), it is conjectured that for , a line graph is -hamiltonian if and only if is -connected. In this paper we prove the following.(i) For an integer , the line graph of a claw-free graph is -hamiltonian if and only if is -connected.(ii) The line graph of a claw-free graph is 1-hamiltonian connected if and only if is 4-connected. 相似文献
20.
Dr. Chen-Ming Lin Maritess Arancillo Jonathan Whisenant Prof. Kevin Burgess 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(24):9484-9488
Secondary structures tend to be recognizable because they have repeating structural motifs, but mimicry of these does not have to follow such well-defined patterns. Bioinformatics studies to match side-chain orientations of a novel hydantoin triazole chemotype ( 1 ) to protein-protein interfaces revealed it tends to align well across parallel and antiparallel sheets, like rungs on a ladder. One set of these overlays was observed for the protein-protein interaction uPA⋅uPAR. Consequently, chemotype 1 was made with appropriate side-chains to mimic uPA at this interface. Biophysical assays indicate these compounds did in fact bind uPAR, and elicit cellular responses that affected invasion, migration, and wound healing. 相似文献