全文获取类型
收费全文 | 2706篇 |
免费 | 473篇 |
国内免费 | 176篇 |
专业分类
化学 | 456篇 |
晶体学 | 10篇 |
力学 | 875篇 |
综合类 | 28篇 |
数学 | 193篇 |
物理学 | 1793篇 |
出版年
2024年 | 4篇 |
2023年 | 29篇 |
2022年 | 35篇 |
2021年 | 37篇 |
2020年 | 66篇 |
2019年 | 55篇 |
2018年 | 62篇 |
2017年 | 86篇 |
2016年 | 76篇 |
2015年 | 100篇 |
2014年 | 158篇 |
2013年 | 173篇 |
2012年 | 209篇 |
2011年 | 209篇 |
2010年 | 149篇 |
2009年 | 176篇 |
2008年 | 167篇 |
2007年 | 159篇 |
2006年 | 134篇 |
2005年 | 154篇 |
2004年 | 122篇 |
2003年 | 120篇 |
2002年 | 97篇 |
2001年 | 87篇 |
2000年 | 73篇 |
1999年 | 82篇 |
1998年 | 58篇 |
1997年 | 50篇 |
1996年 | 48篇 |
1995年 | 61篇 |
1994年 | 46篇 |
1993年 | 49篇 |
1992年 | 22篇 |
1991年 | 33篇 |
1990年 | 18篇 |
1989年 | 27篇 |
1988年 | 25篇 |
1987年 | 20篇 |
1986年 | 13篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1980年 | 3篇 |
1979年 | 7篇 |
1978年 | 11篇 |
1976年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有3355条查询结果,搜索用时 15 毫秒
1.
X-ray emission for Ar11+ ions impacting on various targets in the collisions near the Bohr velocity 下载免费PDF全文
Xian-Ming Zhou 《中国物理 B》2021,30(8):83201-083201
X-ray emission from the collisions of 3 MeV Ar11+ ions with V, Fe, Co, Ni, Cu, and Zn is investigated. Both the x-rays of the target atom and projectile are observed simultaneously. The x-ray yield is extracted from the original count. The inner-shell ionization cross section is estimated by the binary encounter approximation model and compared with the experimental result. The remarkable result is that the Ar K-shell x-ray yield is diminished with the target atomic number increasing, which is completely opposite to the theoretical calculation. That is interpreted by the competitive consumption of the energy loss for the ionization of inner-shell electrons between the projectile and target atom. 相似文献
2.
《Mathematical Methods in the Applied Sciences》2018,41(9):3294-3306
In this article, we consider the asymptotic behavior of the classical solution to the 3‐dimensional Vlasov‐Poisson plasma interacting repulsively with N point charges. The large time behavior in terms of diameters of its velocity‐spatial supports is improved to O(t2/3+ϵ) for any ϵ>0. 相似文献
3.
4.
飞行器角速度的测量在航空航天领域是极为重要的问题,然而现在主流的利用陀螺仪测量角速度的方法有造价较高这一问题。本文提出了一种通过测量刚体上非共线三点的加速度得到刚体角速度的方法,可以利用极为廉价的高精度加速度计较为准确地测量高速稳态飞行器的角速度。本文应用刚体运动学中的基点法,得到由刚体上非共线三点的加速度和其距离表示的刚体角速度,并对其进行了误差分析。最终采用数值模拟的方法,分析了此方法在具有较高角速度的飞行器和具有较低角速度的稳态卫星上得到的角速度的适用性。模拟结果表明,此种方法适用于稳态高角速度的飞行器。 相似文献
5.
6.
在EAST装置上安装了X模极化W波段多道相关反射仪,用于测量等离子体芯部密度涨落。该诊断利用低损耗(<3dB)多工器将4个不同频率(79.2GHz,85.2GHz,91.8GHz和96GHz)的微波耦合在一起,通过同一个天线发射。反射波由两个极向分离(~5cm)的天线接收,通过下变频技术实现外差测量。通过对两个极向天线接收的信号进行相关分析,获得芯部湍流垂直速度。对2018年低约束模式(L模)放电进行分析发现,在电子回旋共振加热(ECRH)等离子体中,芯部湍流垂直速度在电子逆磁漂移方向。而在注入同向中性束(co-NBI)后,芯部湍流垂直速度变为离子逆磁漂移方向。 相似文献
7.
为研究含有少量奥克托金(HMX)且以三氨基三硝基苯(TATB)为基的高能钝感炸药PBX-3的冲击起爆反应增长规律,采用火炮驱动蓝宝石飞片的方法和铝基组合式电磁粒子速度计技术进行了一维平面冲击实验。通过实验测量撞击表面及内部不同深度处的冲击波后粒子速度,得到PBX-3炸药的Hugoniot关系。根据冲击波示踪器所测数据绘制了炸药到爆轰的时间-距离(x-t)图,获得了反映炸药冲击起爆性能的Pop关系。将入射压力为12.964 GPa时达到爆轰的6条速度曲线修整成相同零点,通过读取6条曲线的分离点即反应区末端的C-J点,计算出化学反应区时间和宽度。 相似文献
8.
Cover Picture: Velocity of a Molecule Evaporated from a Water Nanodroplet: Maxwell–Boltzmann Statistics versus Non‐Ergodic Events (Angew. Chem. Int. Ed. 49/2015) 下载免费PDF全文
Assist. Prof. Dr. Hassan Abdoul‐Carime Francis Berthias Dr. Linda Feketeová Dr. Mathieu Marciante Dr. Florent Calvo Dr. Valérian Forquet Prof. Dr. Henry Chermette Dr. Bernadette Farizon Prof. Dr. Michel Farizon Prof. Dr. Tilmann D. Märk 《Angewandte Chemie (International ed. in English)》2015,54(49):14587-14587
9.
Sound velocities in molten ((LiF + AgI)) and ((LiBr + AgI)) mixtures have been measured to investigate the relationship between the sound velocity and the temperature and the role of the anion in the (liquid + liquid) phase transition. Our results show that the ((LiBr + AgI)) system is biphasic between the melting point and T = 984 K and becomes monophasic above this temperature. We show that the upper consolute critical temperature for the AgI-containing melts increases with decreasing anion size in the series F− > Cl− > Br−. The ((LiF + AgI)) melt remains biphasic at all temperatures investigated up to T = 1218 K. The temperature coefficients for the sound velocities in the upper and lower phases of the ((LiBr + AgI)) system have opposite signs because of the superposition of the temperature and composition factors. The difference between the magnitudes of the velocities for the coexisting phases decreases exponentially with increasing temperature and is described by a critical exponent of 0.85 for the ((LiBr + AgI)) melt near the critical temperature. This value is 15% less than that found for alkali halide melts, in which long-range Coulomb forces between ions prevail. This difference may result from the fact that silver halides are intermediate between the typical ionic salts and the fully covalently bonded ones. 相似文献
10.
Liver regeneration has been studied for decades; however, its regulation remains unclear. In this study, we report a dynamic tracing of protein synthesis in rat regenerating liver with a new proteomic technique, 35S in vivo labeling analysis for dynamic proteomics (SiLAD). Conventional proteomic techniques typically measure protein alteration in accumulated amounts. The SiLAD technique specifically detects protein synthesis velocity instead of accumulated amounts of protein through 35S pulse labeling of newly synthesized proteins, providing a direct way for analyzing protein synthesis variations. Consequently, protein synthesis within short as 30 min was visualized and protein regulations in the first 8 h of regenerating liver were dynamically traced. Further, the 3.5–5 h post partial hepatectomy (PHx) was shown to be an important regulatory turning point by acute regulation of many proteins in the initiation of liver regeneration. 相似文献