全文获取类型
收费全文 | 1401篇 |
免费 | 152篇 |
国内免费 | 109篇 |
专业分类
化学 | 1006篇 |
晶体学 | 14篇 |
力学 | 92篇 |
综合类 | 17篇 |
数学 | 119篇 |
物理学 | 414篇 |
出版年
2023年 | 28篇 |
2022年 | 24篇 |
2021年 | 32篇 |
2020年 | 40篇 |
2019年 | 43篇 |
2018年 | 38篇 |
2017年 | 28篇 |
2016年 | 55篇 |
2015年 | 54篇 |
2014年 | 69篇 |
2013年 | 91篇 |
2012年 | 87篇 |
2011年 | 106篇 |
2010年 | 63篇 |
2009年 | 68篇 |
2008年 | 83篇 |
2007年 | 100篇 |
2006年 | 97篇 |
2005年 | 64篇 |
2004年 | 50篇 |
2003年 | 57篇 |
2002年 | 53篇 |
2001年 | 36篇 |
2000年 | 42篇 |
1999年 | 38篇 |
1998年 | 31篇 |
1997年 | 24篇 |
1996年 | 16篇 |
1995年 | 19篇 |
1994年 | 10篇 |
1993年 | 18篇 |
1992年 | 17篇 |
1991年 | 12篇 |
1990年 | 10篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1971年 | 3篇 |
1969年 | 1篇 |
1968年 | 3篇 |
1957年 | 1篇 |
排序方式: 共有1662条查询结果,搜索用时 46 毫秒
991.
Luo Gangjie Li Li Fang Qihong Li Jia Tian Yuanyuan Liu Yong Liu Bin Peng Jing Liaw P. K. 《应用数学和力学(英文版)》2021,42(8):1109-1122
High entropy alloys(HEAs) attract remarkable attention due to the excellent mechanical performance. However, the origins of their high strength and toughness compared with those of the traditional alloys are still hardly revealed. Here, using a microstructure-based constitutive model and molecular dynamics(MD) simulation, we investigate the unique mechanical behavior and microstructure evolution of FeCoCrNiCu HEAs during the indentation. Due to the interaction between the dislocation and solution,the high dislocation density in FeCoCrNiCu leads to strong work hardening. Plentiful slip systems are stimulated, leading to the good plasticity of FeCoCrNiCu. The plastic deformation of FeCoCrNiCu is basically affected by the motion of dislocation loops. The prismatic dislocation loops inside FeCoCrNiCu are formed by the dislocations with the Burgers vectors of a/6[■] and a/6[■], which interact with each other, and then emit along the ■slip direction. In addition, the mechanical properties of FeCoCrNiCu HEA can be predicted by constructing the microstructure-based constitutive model, which is identified according to the evolution of the dislocation density and the stress-strain curve.Strong dislocation strengthening and remarkable lattice distortion strengthening occur in the deformation process of FeCoCrNiCu, and improve the strength. Therefore, the origins of high strength and high toughness in FeCoCrNiCu HEAs come from lattice distortion strengthening and the more activable slip systems compared with Cu. These results accelerate the discovery of HEAs with excellent mechanical properties, and provide a valuable reference for the industrial application of HEAs. 相似文献
992.
漫射物体的压缩全息利用其非相干散射密度函数在统计意义上满足稀疏先验这一假设,可以从多幅散斑图案实现漫射物体的层析重建,避免了散斑和不同平面的散焦图像之间的串扰。将单波长照明条件拓展到红、绿、蓝三色波长,提出一种新的适用于彩色漫射物体的压缩全息层析成像方法,搭建多波长照明条件下漫射物体的层析成像模型,并通过解压缩推理方法有效地分离不同平面的三维非相干密度函数。数值模拟实验表明,所提方法可以在多幅二维彩色散斑图案中成功进行彩色层析漫射物体的压缩重建,有效地抑制了散斑效应以及不同平面的散焦图像之间的相互串扰。 相似文献
993.
Mark Louis P. Vidallon Alon M. Douek Adam Quek Heather McLiesh Jan Kaslin Rico F. Tabor Alexis I. Bishop Boon Mian Teo 《Particle & Particle Systems Characterization》2020,37(2):1900471
This work reports the fabrication of biocompatible and pH-sensitive hybrid polydopamine/bovine serum albumin/calcium carbonate (PDA/BSA/CaCO3) particles via a rapid precipitation method. These hybrid particles generate hyperechogenic carbon dioxide bubbles upon exposure to low pH environments, making them ideal as a contrast agent and detector for tumor cells. This study also highlights the application of red blood cell membrane (RBC)-derived membranes as a biomimetic coating for PDA/BSA/CaCO3 hybrid particles in order to modulate protein corona formation, a natural physiological response that alters tailored properties of most nanomaterials that are administered systemically. Results of this work demonstrate that the RBC membrane-coated hybrid particles are ideal for a wide range of biomedical applications, such as noninvasive multimodal imaging, photothermal and photodynamic therapy, and “personalized” drug delivery systems. 相似文献
994.
Maarten Honing Chris Martini Monique van Velzen Marieke Niesters Albert Dahan Martijn Boon 《Molecules (Basel, Switzerland)》2020,25(24)
General anesthesia is obtained by administration of potent hypnotics, analgesics and muscle relaxants. Apart from their intended effects (loss of consciousness, pain relief and muscle relaxation), these agents profoundly affect the control of breathing, in part by an effect within the peripheral chemoreflex loop that originates at the carotid bodies. This review assesses the role of cholinergic chemotransmission in the peripheral chemoreflex loop and the mechanisms through which muscle relaxants and hypnotics interfere with peripheral chemosensitivity. Additionally, consequences for clinical practice are discussed. 相似文献
995.
Shan Li Fengxian Bai Ruifang Wang Chen Chen Xiaofang Li Feng Cao Bo Yu Jiehe Sui Xingjun Liu Zhifeng Ren Qian Zhang 《Annalen der Physik》2020,532(11):1900440
The 19-electron VCoSb compounds are actually composites of an off-stoichiometric half-Heusler phase and impurities. Here the compositional adjustment is systematically studied in V1−xCoSb to obtain single-phase V0.955CoSb. Hall measurements suggest that such a V vacancy, as well as Ti doping, can optimize the carrier concentration, which decreases from ≈11.3 × 1021 cm−3 for VCoSb to ≈6.3 × 1021 cm−3 for V0.755Ti0.2CoSb. Low sound velocity contributes to the intrinsically low lattice thermal conductivity for VCoSb-based materials. The high Ti-dopant content results in enhanced point-defect scattering, which further decreases the lattice thermal conductivity. Finally, the optimized n-type V0.855Ti0.1CoSb is found to reach a peak ZT of ≈0.7 at 973 K. The work demonstrates that the VCoSb-based half-Heuslers are promising thermoelectric materials. 相似文献
996.
Zhao Jialin Sui Ying Peng Xiujing Sun Guoxin Cui Yu 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(1):339-348
Journal of Radioanalytical and Nuclear Chemistry - Nuclear grade zirconium and hafnium are the key to promoting the development of nuclear industry. We designed and synthesized a new diphosphonic... 相似文献
997.
Lin Sui Li Dr. Wen Juan Wei Hong Qiang Gao Yu Hui Tan Dr. Xiao Bo Han 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(35):9054-9059
Two-dimensional hybrid halide perovskites with single chiral and ferroelectricity together with various structural phase transitions provide the possibility for more diverse functional properties. Here, we present a 2D chiral hybrid halide perovskite ferroelectric, [C6H5(CH2)4NH3]2CdCl4 (4PBA−CdCl4, 4PBA=4-phenylbutylamine) that experiences two continuous phase transitions from centrosymmetric triclinic P to polar chiral monoclinic P2 and then to another centrosymmetric tetragonal P4/mmm with increasing temperature, accompanied by symmetry breaking, due to the prominent octahedral distortion and disorder transformation of organic 4PBA cations. In the polar chiral phase, 4PBA−CdCl4 gives a significant CD signal and has a moderate ferroelectric polarization of 0.35 μC/cm2. In addition, 4PBA−CdCl4 occupies a wide band gap of 4.376 eV that is chiefly contributed by the inorganic CdCl6 octahedron. This finding offers an alternative pathway for designing new phase transitions and related physical properties in hybrid halide perovskites and other hybrid crystals. 相似文献
998.
Ma Zhengwei Sui Weihong Liu Jing Wang Wenjun Li Songmei Chen Tiantian Yang Guanglei Zhu Kaixing Li Zhenjiang 《Journal of Solid State Electrochemistry》2022,26(4):973-984
Journal of Solid State Electrochemistry - Lithium-sulfur batteries are of significant roles in the next-generation energy storage devices due to the high theoretical capacity and energy density.... 相似文献
999.
1000.
Wei‐Ren Lian Han‐Yu Wu Kun‐Li Wang Der‐Jang Liaw Kueir‐Rarn Lee Juin‐Yih Lai 《Journal of polymer science. Part A, Polymer chemistry》2011,49(17):3673-3680
A high‐glass‐transition‐temperature polynorbornene, poly(NBEDPY), containing chromophore groups was synthesized by ring‐opening metathesis polymerization (ROMP) using Grubbs' catalysts; poly(HNBEDPY) was obtained by the reduction of poly(NBEDPY). The glass transition temperatures (Tg) of poly(NBEDPY) and hydrogenated poly(HNBEDPY) were as high as 250 °C and 220 °C, respectively, because of the rigid dipyrene groups, which are higher than those of commercially available ring‐opened hydrogenated polynorbornenes (JSR ARTON®; 120–165 °C). The 10% weight‐loss temperatures of hydrogenated poly(HNBEDPY) and poly(NBEDPY) were up to 450 °C and 400 °C, respectively. A hydrogenated poly (HNBEDPY) film showed excellent transparency (over 91%). The photoluminescence emission spectra of poly(HNBEDPY) showed strong solvent‐polarity dependence, revealing that poly (HNBEDPY) underwent remarkable bathochromic shifts with an increase in solvent polarity. Poly(HNBEDPY) also showed remarkable fluorescent solvatochromism (blue in toluene, greenish yellow in dimethyl sulfoxide). The cyclic voltammogram of poly(HNBEDPY) film cast onto an indium tin oxide (ITO)‐coated glass substrate exhibited one reversible oxidation redox couple at 0.55 V versus Ag/Ag+ in acetonitrile solution. The electrochromic characteristics of poly(HNBEDPY) showed reversibility, with a color change from its green neutral form to dark red upon the application of potentials from 0 to 1.0 V. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献