全文获取类型
收费全文 | 1976篇 |
免费 | 211篇 |
国内免费 | 113篇 |
专业分类
化学 | 1179篇 |
晶体学 | 7篇 |
力学 | 64篇 |
综合类 | 34篇 |
数学 | 83篇 |
物理学 | 933篇 |
出版年
2024年 | 8篇 |
2023年 | 43篇 |
2022年 | 62篇 |
2021年 | 68篇 |
2020年 | 64篇 |
2019年 | 82篇 |
2018年 | 61篇 |
2017年 | 83篇 |
2016年 | 81篇 |
2015年 | 63篇 |
2014年 | 74篇 |
2013年 | 158篇 |
2012年 | 111篇 |
2011年 | 101篇 |
2010年 | 104篇 |
2009年 | 109篇 |
2008年 | 122篇 |
2007年 | 115篇 |
2006年 | 100篇 |
2005年 | 100篇 |
2004年 | 71篇 |
2003年 | 51篇 |
2002年 | 60篇 |
2001年 | 65篇 |
2000年 | 75篇 |
1999年 | 30篇 |
1998年 | 44篇 |
1997年 | 23篇 |
1996年 | 10篇 |
1995年 | 21篇 |
1994年 | 25篇 |
1993年 | 13篇 |
1992年 | 19篇 |
1991年 | 8篇 |
1990年 | 8篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有2300条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
M. Uihlein 《Chromatographia》1979,12(6):408-411
Summary Pharmacokinetic studies require a great number of serum drug levels to be determined. It is therefore necessary to rationalize analytical methods. Methods for rational clean-up procedures and the determination by means of mechanized HPLC are shown. The following quality criteria for determination methods are proposed: precision, accuracy, specificity and sensitivity. Quality control in routine analyses is performed by evaluating the criteria of parallel analyses of known admixtures to serum. 相似文献
995.
本文用相对论多组态Dirac-Fock广义平均能级(MCDF—EAL)模型计算了可能成为激光工作物质的类氧离子CoⅩⅩ,NiⅩⅪ,CuⅩⅩⅡ和ZnⅩⅩⅢ的48个精细结构能级和93个3s—3p跃迁波长。3p组态能级和3s—3p跃迁波长是本文首次预言的。 相似文献
996.
B. Cederwall T. Bäck R. Wyss A. Johnson J. Cederkäll M. Devlin J. Elson D.R. LaFosse F. Lerma D.G. Sarantites R.M. Clark P. Fallon I.Y. Lee A.O. Macchiavelli R.W. Macleod 《The European Physical Journal A - Hadrons and Nuclei》1999,5(3):251-255
A superdeformed band consisting of a cascade of ten γ-ray transitions has been identified and assigned to the nucleus 89Tc, close to the proton dripline. The quadrupole moment of the band (Q
t= 6.7+3.0
−2.3
eb, as measured by the Residual Doppler Shift Method) as well as a large dynamic moment of inertia point to a highly elongated
shape. With a relative population of approximately 15% of the γ-ray flux in the 89Tc exit channel, the band is among the most intense superdeformed bands observed to date.
Received: 6 July 1999 相似文献
997.
D.C. Biswas R.K. Choudhury M. Cinausero B. Fornal D.V. Shetty G. Viesti D. Fabris E. Fioretto M. Lunardon G. Nebbia G. Prete D. Bazzacco M. DePoli D.R. Napoli C.A. Ur G. Vedovato 《The European Physical Journal A - Hadrons and Nuclei》2000,7(2):189-195
Measurements of fission fragment yields and neutron multiplicities have been carried out for the Mo-Ba fragment pairs in
the spontaneous fission of 252Cf, using the γ-ray spectroscopy technique to analyze γ-γ-γ coincidence data. Prompt γ -ray multiplicities were also measured
as a function of the number of neutrons emitted in the fission process leading to the Mo-Ba partition. We do not observe the
enhancement in the yields of events with high neutron emission multiplicity (νn > 7) that has been associated to a second fission mode leading to the production of hyperdeformed Ba fragments, as reported
in some earlier studies. The average γ-ray multiplicity is found to be rather weakly dependent on the number of neutrons emitted
in the fission process.
Received: 21 July 1999 / Revised version: 19 November 1999 相似文献
998.
B Mukherjee S Muralithar R P Singh R Kumar K Rani S C Pancholi R K Bhowmik 《Pramana》2000,55(3):L471-L478
Excited states of 63Cu were populated via the 52Cr+10O (65 MeV) reaction using the gamma detector array equipped with charged particle detector array for reaction channel separation.
On the basis of γ-γ coincidence relations and angular distribution ratios, a level scheme was constructed up to E
n=7 MeV and J
π=23/2(+). The decay scheme deduced was interpreted in terms of shell model calculations, with a restricted basis of the f
5/2, p
3/2, p
1/2, g
9/2 orbitals outside a 56
28Ni core. 相似文献
999.
G. Kemper A. Dewald I. Wiedenhöver R. Peusquens S. Kasemann K.O. Zell P. von Brentano H. Hübel S. Chmel A. Görgen D. Bazzacco R. Venturelli S. Lunardi D.R. Napoli F. Hannachi A. Lopez-Martens R. Krücken J.R. Cooper R.M. Clark M.A. Deleplanque I.Y. Lee A.O. Machiavelli F.S. Stephens 《The European Physical Journal A - Hadrons and Nuclei》2001,11(2):121-124
Lifetimes for low-lying members of the irregular ΔI = 1 band in 196Pb have been measured by means of the EUROBALL spectrometer using the coincidence recoil distance technique. The 164Dy(36S,4n)196Pb reaction at a beam energy of 168 MeV was used. The data were analyzed with the differential decay-curve method (DDCM).
A characteristic drop in the reduced transition probabilities with increasing angular momentum was observed in agreement with
predictions by the semiclassical model for the shears mechanism.
Received: 3 May 2001 / Accepted: 20 June 2001 相似文献
1000.
基于时变需求的库存问题一直是库存管理者关注的重点之一,大多数基于二层信用支付的库存模型都是假设需求率为常数.假设需求率是时间的指数函数,建立了二层信用支付条件下的变质物品库存模型,并证明了最优解是存在且唯一的,给出了确定最优补货策略的算法步骤,最后通过数值例子对主要参数进行了灵敏度分析. 相似文献