全文获取类型
收费全文 | 98738篇 |
免费 | 5716篇 |
国内免费 | 4620篇 |
专业分类
化学 | 56203篇 |
晶体学 | 1331篇 |
力学 | 5582篇 |
综合类 | 322篇 |
数学 | 11832篇 |
物理学 | 33804篇 |
出版年
2023年 | 749篇 |
2022年 | 1710篇 |
2021年 | 2051篇 |
2020年 | 2310篇 |
2019年 | 2507篇 |
2018年 | 2893篇 |
2017年 | 2823篇 |
2016年 | 3488篇 |
2015年 | 2412篇 |
2014年 | 3478篇 |
2013年 | 4917篇 |
2012年 | 5055篇 |
2011年 | 5354篇 |
2010年 | 4250篇 |
2009年 | 4255篇 |
2008年 | 4453篇 |
2007年 | 4174篇 |
2006年 | 3804篇 |
2005年 | 3375篇 |
2004年 | 3036篇 |
2003年 | 2711篇 |
2002年 | 2828篇 |
2001年 | 2547篇 |
2000年 | 1987篇 |
1999年 | 1601篇 |
1998年 | 1535篇 |
1997年 | 1331篇 |
1996年 | 1295篇 |
1995年 | 1077篇 |
1994年 | 1156篇 |
1993年 | 1095篇 |
1992年 | 1062篇 |
1991年 | 1124篇 |
1990年 | 1118篇 |
1989年 | 1039篇 |
1988年 | 917篇 |
1987年 | 914篇 |
1986年 | 882篇 |
1985年 | 922篇 |
1984年 | 915篇 |
1983年 | 822篇 |
1982年 | 800篇 |
1979年 | 801篇 |
1978年 | 812篇 |
1977年 | 806篇 |
1976年 | 919篇 |
1975年 | 812篇 |
1974年 | 844篇 |
1973年 | 847篇 |
1972年 | 752篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
文章提出了大学研究性物理实验与创新心理品质培养的主题,介绍了大学研究性物理实验的特点,论述了大学研究性物理实验对大学生创新心理品质的影响。 相似文献
102.
The excitation of eigen surface waves by tubular electron beams in cylindrical discharge devices is studied. The influence of the wave‐field azimuthal structure on the excitation efficiency and nonlinear stage of the plasmabeam instability is investigated both numerically and analytically. Analytical expressions for the saturation amplitude and excitation efficiency of the wave under study are derived. They are found to agree well with results obtained by numerical modelling of the plasma‐beam interaction presented in this paper. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
103.
V. Yu. Baranovskii L. L. Yasina M. V. Motyakin I. I. Aliev S. Shenkov M. Dimitrov N. Lambov A. M. Wasserman 《Polymer Science Series A》2006,48(12):1304-1309
Partially water-swellable polymer networks were synthesized on the basis of poly(acrylic acid) and various macrodiisocyanates. Hydrophilic and hydrophobic local regions were revealed in swollen networks (hydrogels) by means of the spin probe technique. The local mobility in hydrophobic regions depends on the macrodiisocyanate structure; however, it is substantially lower than that in hydrophilic regions for all gels. It was assumed that the presence of hydrophobic and hydrophilic regions and the difference in their local dynamics must have a substantial effect on the pharmacokinetics of release of drugs immobilized in these hydrogels. 相似文献
104.
105.
The problem of the stability of a heavy rigid body, bounded by the surface of an ellipsoid and with a cavity in the form of a coaxial ellipsoid, rolling along a straight line on a horizontal rough plane is investigated. It is shown that in the case of a body that is close to being dynamically symmetrical, parametric resonance always occurs leading to instability of the rolling. Each ellipsoid has its own “individual” resonance angular velocity. In the general case, regions in which the necessary stability conditions are satisfied can be distinguished in parameter space. The problem of calculating the resonance coefficient corresponding to instability for parametric resonance in a reversible third-order system is solved. 相似文献
106.
〈I〉型三角剖分下非张量积连续小波基的构造 总被引:1,自引:0,他引:1
多维非张量积小波是近年小波研究领域中的热点问题之一 ,它们与多维张量积小波相比具有更多的优势 .关于高维张量积、非张量积小波 ,目前已有一些很好的工作 (见文[2 ] [3 ] [4 ] ) ,但关于样条小波 ,还有许多问题有待于研究 .本文针对〈I〉型三角剖分下的二维线性元空间 ,讨论其具有紧支集和对称性的半正交样条小波基 .给定 x1 x2 平面上的〈I〉型三角剖分 (图 1 ( a)所示 ) ,记 j=( j1 ,j2 ) ,| j| =j1 + j2 ,πm= { 0≤ |j|≤ mCj1j2 xj11 xj22 ,Cj1,j2 是任意实数 }为次数不超过 m的代数多项式全体 .引入剖分尺度为 1的线性元空间 V0… 相似文献
107.
A. Yu. Toporov 《Technical Physics》2002,47(9):1199-1201
Antidots of size 0.5 μm are prepared by patterning iron-nickel films with a focused ion beam. The magnetization distribution in antidot arrays is examined with Lorentz transmission electron microscopy. It is shown that one side of the array makes an angle of about 20° with the easy magnetic axis of the film. Magnetization reversal in the direction close to the easy magnetic axis starts with domain nucleation at the antidot edges that are perpendicular to the applied field and adjacent to the unpatterned region of the film, and propagates as the domain walls move. Magnetization reversal in the direction close to the hard magnetic axis starts with magnetization rotation outside the patterned region at the antidot edges and propagates as the domain walls execute a complicated motion. It is demonstrated that some areas between the edges of adjacent antidots can carry information bits. Results obtained are explained in terms of competition between the demagnetizing energy, energy of internal anisotropy, and misorientation effect. The feasibility of such structures as high-density storage elements is discussed. 相似文献
108.
A. R. Volkov B. V. Shul'gin T. I. Polupanova V. N. Lebedev A. A. Nagornyi V. L. Petrov Yu. F. Kargin 《Journal of Applied Spectroscopy》1991,54(6):585-590
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 54, No. 6, pp. 970–975, June, 1991. 相似文献
109.
E. V. Zakharov A. G. Davydov Yu. V. Pimenov G. M. Tikhonov 《Computational Mathematics and Modeling》1991,2(1):79-84
Translated from Chislennye Metody Resheniya Obratnykh Zadach Matematicheskoi Fiziki, pp. 119–127. 相似文献
110.