全文获取类型
收费全文 | 10374篇 |
免费 | 328篇 |
国内免费 | 2篇 |
专业分类
化学 | 5401篇 |
晶体学 | 105篇 |
力学 | 186篇 |
数学 | 2069篇 |
物理学 | 2943篇 |
出版年
2021年 | 148篇 |
2020年 | 140篇 |
2019年 | 128篇 |
2018年 | 199篇 |
2017年 | 222篇 |
2016年 | 466篇 |
2015年 | 308篇 |
2014年 | 353篇 |
2013年 | 800篇 |
2012年 | 485篇 |
2011年 | 620篇 |
2010年 | 400篇 |
2009年 | 342篇 |
2008年 | 318篇 |
2007年 | 273篇 |
2006年 | 203篇 |
2005年 | 161篇 |
2004年 | 156篇 |
2003年 | 157篇 |
2002年 | 167篇 |
2001年 | 137篇 |
2000年 | 128篇 |
1999年 | 138篇 |
1998年 | 129篇 |
1997年 | 126篇 |
1996年 | 133篇 |
1995年 | 118篇 |
1994年 | 111篇 |
1993年 | 121篇 |
1992年 | 116篇 |
1991年 | 104篇 |
1990年 | 105篇 |
1989年 | 101篇 |
1988年 | 99篇 |
1987年 | 121篇 |
1986年 | 88篇 |
1985年 | 128篇 |
1984年 | 127篇 |
1983年 | 118篇 |
1982年 | 108篇 |
1981年 | 111篇 |
1980年 | 110篇 |
1979年 | 120篇 |
1978年 | 118篇 |
1977年 | 113篇 |
1976年 | 112篇 |
1975年 | 94篇 |
1974年 | 101篇 |
1973年 | 102篇 |
1966年 | 82篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
M. Rotter B. Sedlák J. Englich P. Čížek M. Finger P. Malinský V. N. Pavlov 《Hyperfine Interactions》1987,34(1-4):303-306
The results of NMR/ON measurements on56'57'60Co isotopes in iron are presented. To avoid the uncertainties caused by local demagnetizing field inhomogenities the measurements on two cobalt isotopes in one sample have been carried out. The values of nuclear-factor ratios
57/
60 = 1.805 (20),
60/
56 = 0.761 (20),
56/
57 = 0.726 (20) and hyperfine anomalies5660 = -0.036 (10),60
57 = 0.017 (10) and5756 = 0.018 (10) have been calculated from the experimental results. 相似文献
132.
In the framework of path integrals we present a solution to the Schrödinger equation for a free particle confined to the half-linex > 0. A solution in question corresponds to the boundary condition (/x) (0,t)= (0,t) where is a real constant. 相似文献
133.
M. Rotter B. Sedlák J. Englich P. Čížek M. Finger P. Malinský 《Czechoslovak Journal of Physics》1986,36(11):1331-1335
The results of NMR/ON measurements on56,57,60Co isotopes in iron are presented in the paper. To avoid the uncertainties caused by local demagnetizing field inhomogeneities the measurements on two cobalt isotopes in one sample have been carried out. The values of nuclear-factors ratios
57/
60=1·805(20),
60/
56 = 0·761(20),
56/
57 = 0·726(20) and hyperfme anomalies56
60 = –0·036(10),60
57 = 0·017(10) and57
56 = 0·018(10) have been calculated from the experimental results.Dedicated to the 30th anniversary of the Joint Institute for Nuclear Research. 相似文献
134.
135.
Mikuláš Blažek 《Zeitschrift fur Physik C Particles and Fields》1986,32(2):309-316
The energy dependent parameter characterizing the leading particle effect allows to restore the scaling in proton-proton and antiproton-proton multiplicity distributions from Serpukhov until highest available CERN \(S \bar ppS\) collider energies. The identification of theoretical second dispersions with the experimental ones represents one of the basic ingredients in the quantum statistical bosonic approach applied in the present contribution. The KNO scaling at the ISR energies as well as the Worblewski relation for the second dispersions at the \(S \bar ppS\) collider energies arise quite naturally; similar phenomena might appear at higher energies too. Some predictions for 2 and 10 TeV cms energies are specified. 相似文献
136.
Dobrochna Matkowska Maciej Gola Marcin ?nie?ek Piotr Cmoch Krzysztof Staliński 《Journal of organometallic chemistry》2007,692(10):2036-2045
A series of triorganotin hydrides and diorganotin dihydrides containing the optically active 2-(4-isopropyl-2-oxazolinyl)-5-phenyl ligand have been characterized by means of the multinuclear low-temperature NMR investigations, the results of which are discussed. In the corresponding organotin hydrides values of the 1J(1H-117/119Sn) couplings appeared to be temperature dependent, supporting an axial/equatorial position of the hydrogen attached to the tin. 相似文献
137.
J. Brandštetr 《Journal of Thermal Analysis and Calorimetry》1981,21(2):357-365
A review of instruments for thermochemical (thermometric) solution analysis is given, including new types of isoperibol reaction of bomb calorimeters, the design of which can influence the future development of thermochemical measuring techniques. The new type of Dithermanal (Vaskut-EMG, Hungary, and Herrmann- Morris, France) controls the individual steps of the thermochemical analysis, adding memory and computing capabilities. Similar programming units with microprocessors for bomb and/or reaction calorimetry have been developed by Parr Comp. and Leco Comp. (USA). The latest modification of the Technicon flow analyzer permits on-line analysis of solid samples. For thermochemical titrations, the Sanda titrator (USA) and Vaskut automatic titrator (Hungary) are available. In the USA, the Tronac isothermal or isoperibol calorimeters are widely used. At the Technical University of Brno, ?SSR, smaller table instruments with a water-bath are applied for different modes of solution thermochemical analysis, and also for the reactions of solid samples in liquids. For the measurement of very small temperature differences, PTC thermistors are used. The possibilities of the future development of measuring techniques are outlined. 相似文献
138.
Nataša Bukovec 《Thermochimica Acta》1985,96(2):391-395
The thermal decomposition of N2H5Nd(SO4)2·H2O has been studied by simultaneous TG and DSC and by isothermal weight change determination. The final product and the intermediate phases have been identified by chemical analysis, X-ray powder patterns and infrared spectroscopy. The solid phases in the decomposition sequence are: N2H5Nd(SO4)2· H2O → N2H5Nd(SO4)2 → NH4Nd(SO4)2 → Nd2(SO4)3. The reactions overlap under dynamicconditions, isothermally, however, NH4Nd(SO4)2 can be obtained by 200°C. 相似文献
139.
Summary High-molecular-weight sodium hyaluronate isolated from rooster combs was degraded by ultrasonication. The molecular weight of hyaluronate and its polydispersity was determined by gel-permeation chromatography. During 75-min treatment the molecular weight value decreased from 1.39×106 Da to 2.25×105 Da while the polydispersity of the molecular weight increased from 1.29 to 2.36. The reciprocal value of the square of the hyaluronate's molecular weight was linearly proportional to the time of ultrasonication. 相似文献
140.
Summary A high molecular weight sodium hyaluronate isolated from rooster combs was degraded by ultrasonication. High-performance size exclusion chromatography allowed rapid and accurate determination of molecular weight parameters (Mz, Mw, Mn) and distributions. The time dependence of hyaluronan ultrasonication to the molecular characteristics of the polymer was investigated. A non-random nature of the degradation process was demonstrated and the reciprocal Mn value was found to be linearly proportional to the time of ultrasonication. 相似文献