全文获取类型
收费全文 | 9347篇 |
免费 | 2045篇 |
国内免费 | 725篇 |
专业分类
化学 | 2082篇 |
晶体学 | 53篇 |
力学 | 868篇 |
综合类 | 168篇 |
数学 | 3093篇 |
物理学 | 5853篇 |
出版年
2024年 | 20篇 |
2023年 | 70篇 |
2022年 | 220篇 |
2021年 | 280篇 |
2020年 | 295篇 |
2019年 | 290篇 |
2018年 | 248篇 |
2017年 | 328篇 |
2016年 | 373篇 |
2015年 | 359篇 |
2014年 | 596篇 |
2013年 | 765篇 |
2012年 | 587篇 |
2011年 | 746篇 |
2010年 | 586篇 |
2009年 | 560篇 |
2008年 | 584篇 |
2007年 | 730篇 |
2006年 | 603篇 |
2005年 | 488篇 |
2004年 | 452篇 |
2003年 | 412篇 |
2002年 | 354篇 |
2001年 | 310篇 |
2000年 | 313篇 |
1999年 | 230篇 |
1998年 | 173篇 |
1997年 | 183篇 |
1996年 | 147篇 |
1995年 | 103篇 |
1994年 | 96篇 |
1993年 | 71篇 |
1992年 | 74篇 |
1991年 | 78篇 |
1990年 | 47篇 |
1989年 | 48篇 |
1988年 | 44篇 |
1987年 | 28篇 |
1986年 | 26篇 |
1985年 | 33篇 |
1984年 | 24篇 |
1983年 | 13篇 |
1982年 | 26篇 |
1981年 | 20篇 |
1980年 | 15篇 |
1979年 | 14篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 9篇 |
1974年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
Meihua Shen Dr. Xinpeng Zhao Dr. Lu Han Nanxi Jin Prof. Song Liu Prof. Tao Jia Prof. Zhijun Chen Prof. Xiuhua Zhao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(20):e202104137
Solar-driven interfacial vaporization by localizing solar-thermal energy conversion to the air−water interface has attracted tremendous attention. In the process of converting solar energy into heat energy, photothermal materials play an essential role. Herein, a flexible solar-thermal material di-cyan substituted 5,12-dibutylquinacridone (DCN−4CQA)@Paper was developed by coating photothermal quinacridone derivatives on the cellulose paper. The DCN−4CQA@Paper combines desired chemical and physical properties, broadband light-absorbing, and shape-conforming abilities that render efficient photothermic vaporization. Notably, synergetic coupling of solar-steam and solar-electricity technologies by integrating DCN−4CQA@Paper and the thermoelectric devices is realized without trade-offs, highlighting the practical consideration toward more impactful solar heat exploitation. Such solar distillation and low-grade heat-to-electricity generation functions can provide potential opportunities for fresh water and electricity supply in off-grid or remote areas. 相似文献
2.
3.
4.
Leila Torkian Mostafa M. Amini Tayebeh Gorji Omid Sadeghi 《Arabian Journal of Chemistry》2019,12(7):1315-1321
In this study, multiwalled carbon nanotube (MWCNT) was modified by the pyridine group using a silane agent and characterized by infrared spectroscopy (IR), thermal analysis (TG/DTA), and elemental analysis (CHN) and scanning electron microscopy (SEM). The application of this sorbent was investigated in determination of lead ions in aqueous samples, using flame atomic absorption spectrometry (FAAS). Through this study, different parameters such as pH and sample flow rate on adsorption process and eluent concentration, volume and flow rate were optimized. The limit of detection (LOD), the relative standard deviation and the recovery of the method were 2 ng mL?1, 1.3% and 99.7%, respectively. Two standard reference materials (NIST 1571 and NIST 1572) were used to verify accuracy of this method. Finally, the sorbent was successfully applied for extraction and determination of low levels of Pb(II) ions in aqueous samples. 相似文献
5.
Mourad Kainane Mezadek Mohamed Kainane Mezadek Michael Reissig 《Mathematical Methods in the Applied Sciences》2020,43(6):3117-3147
In this paper, we study the global (in time) existence of small data solutions to the Cauchy problem for the semilinear wave equation with friction, viscoelastic damping, and a power nonlinearity. We are interested in the connection between regularity assumptions for the data and the admissible range of exponents p in the power nonlinearity. 相似文献
6.
The possibility of realizing SASE Free Election Laser in x-ray waveband with EM-wave wiggler is studied in this paper. SASE effect including saturation length, saturation power and nonlinear process is explored through a 3-D simulation code. A utilization of seed light from laser plasma x-ray is also analyzed, which demonstrates the feature of shortening the interaction length for saturation. The results show that sizeable output power of x-ray laser would be generated with a middle energy electron beam. 相似文献
7.
Boundedness of commutators on homogeneous Herz spaces 总被引:9,自引:0,他引:9
The boundedness on homogeneous Herz spaces is established for a large class of linear commutators generated by BMO(R
n
) functions and linear operators of rough kernels which include the Calderón-Zygmund operators and the Ricci-Stein oRfiUatory
singular integrals with rough kernels.
Project supponed in pan by the National h’atural Science Foundation of China (Grant No. 19131080) and the NEDF of China. 相似文献
8.
9.
Volker Elling. 《Mathematics of Computation》2006,75(256):1721-1733
A particular case of initial data for the two-dimensional Euler equations is studied numerically. The results show that the Godunov method does not always converge to the physical solution, at least not on feasible grids. Moreover, they suggest that entropy solutions (in the weak entropy inequality sense) are not well posed.
10.
为了描述复杂的噪声环境,考虑了一种具有频率结构的噪声——简谐速度噪声,包括它的产生、关联函数、功率谱以及作为热噪声时的频率特性所导致的一些行为.结果表明:在频谱空间中简谐速度噪声是一种带通噪声,存在一个峰值频率,且噪声带宽由参量Γ控制.当简谐势中的一个布朗粒子受热简谐速度噪声驱动时,粒子能量极大值出现在两种频率相等的情况下.这表明噪声和势场的频率之间存在动力学共振,决定着粒子能量的大小.
关键词:
简谐噪声
简谐速度噪声
功率谱
频率共振 相似文献