全文获取类型
收费全文 | 287篇 |
免费 | 2篇 |
国内免费 | 6篇 |
专业分类
化学 | 100篇 |
晶体学 | 3篇 |
数学 | 52篇 |
物理学 | 140篇 |
出版年
2021年 | 3篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 13篇 |
2012年 | 4篇 |
2011年 | 10篇 |
2010年 | 7篇 |
2009年 | 14篇 |
2008年 | 14篇 |
2007年 | 14篇 |
2006年 | 17篇 |
2005年 | 16篇 |
2004年 | 12篇 |
2003年 | 15篇 |
2002年 | 16篇 |
2001年 | 13篇 |
2000年 | 12篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1964年 | 1篇 |
排序方式: 共有295条查询结果,搜索用时 15 毫秒
211.
212.
Self-consistent density-functional calculations have been carried out for Ag-row impurities in Cs within the spherical solid model. The results for the electronic structure provide an account of the observed resistivity, susceptibility and spin-flip scattering behaviour. 相似文献
213.
H. Kettunen T. Enqvist T. Grahn P.T. Greenlees P. Jones R. Julin S. Juutinen A. Keenan P. Kuusiniemi M. Leino A.-P. Leppänen P. Nieminen J. Pakarinen P. Rahkila J. Uusitalo 《The European Physical Journal A - Hadrons and Nuclei》2003,17(4):537-558
Detailed alpha-decay studies have been performed for the neutron-deficient isotopes 191At and 193At. The nuclei were produced in fusion-evaporation reactions of 54Fe and 56Fe ions with a 141Pr target. The fusion products were separated in-flight using a gas-filled recoil separator and implanted into a position-sensitive silicon detector. The isotopes were identified using position, time and energy correlations between the implants and subsequent alpha-decays. Three alpha-decaying states were identified for 193At and two for 191At. The spin and parity of the initial states in the astatine isotopes were deduced based on unhindered alpha-decays to states in the bismuth daughter nuclei. In both astatine isotopes the 1/2+ intruder state was determined to be the ground state and a 7/2- state to be the first-excited state. In 193At the alpha-decay of the 13/2+ state was observed in coincidence with a previously known gamma-ray transition from the 13/2+ state in the corresponding daughter nucleus 189Bi. In 187Bi and 189Bi low-lying 7/2- states were observed for the first time via alpha-decay of the mother nuclei.Received: 16 December 2002, Revised: 26 March 2003, Published online: 4 August 2003PACS:
23.60.+e Alpha decay - 27.80.+w
- 23.20.Lv
transitions and level energies - 21.10.Dr Binding energies and masses 相似文献
214.
The rate of positron detrapping in thermal equilibrium from lattice defects has been calculated by relating it to the specific trapping rate. The results for vacancies, dislocations and surfaces each show a different temperature dependence for the escape rate. For vacancies a measure of the importance of the detrapping can be obtained from the ratio of the vacancy formation energy to the positron binding energy in the defect. The positronium desorption rate from a surface is also calculated and agreement with experimental results is found. 相似文献
215.
Pentti Haukkanen 《Aequationes Mathematicae》1988,35(1):76-81
Arithmetical functionsf andh are said to satisfy the Subbarao identity if
相似文献
216.
Danuta Joanna Mozdyniewicz Kaarlo Nieminen Gregor Kraft Herbert Sixta 《Cellulose (London, England)》2016,23(1):213-229
Novel developments in the fiber sector require additional investigation of their behaviour during the production process. In the core step of the viscose process, cellulose fibres are regenerated in an acidic spinning bath. To investigate the influence of hemicellulose content and temperature on the kinetics of fiber degradation, standard and hemicellose-enriched fibers were treated in the acidic standard spinning bath for time periods up to 292 h. Viscose samples of different hemicellulose content were prepared under standardized conditions and the never dried fibres were subjected to long term degradation in the standard spinning bath at 40, 50 and 60 °C. The changes in the degree of polymerization (DP), molar mass distribution, hemicellulose and the generation of the total organic carbon in the spinning bath were monitored. Further, the changes in crystallinity and the level-off-DP of the fibers were determined to improve the accuracy of the existing degradation model. Changes in morphology of the fibers were monitored by optical microscopy and scanning electron microscopy. 相似文献
217.
Antti O. K. Nieminen Helena Haataja Marjatta Rautio Erkki Rahkamaa 《Journal of heterocyclic chemistry》1983,20(3):515-517
The 25.1 MHz 13C nmr spectrum of physostigmine in deuteriochloroform has been reanalysed with the aid of high resolution proton coupled spectrum and selective proton irradiation experiments. In addition to unambiguous assignment the analysis yielded values for carbon-proton coupling constants. 相似文献
218.
The aim of the present study was to ellipsometrically determine the thickness and surface mass density in air for up to 110-nm-thick organic layers made of alternatingly deposited layers of HSA and polyclonal anti-HSA on hydrophobic silicon. The ellipsometrically determined thickness was compared to that obtained by AFM and the deposited surface mass density calibrated with (125)I-labeled proteins. The results indicate a good agreement in protein layer thickness between AFM and ellipsometry when the protein film refractive index N(film)=1.5-0i, although then the calculated surface mass density from the ellipsometry data became grossly overestimated by the Cuypers one-component formula. A good agreement in the surface mass density was obtained when the M/A ratio in this formula was lowered from 4.14 to 2.35. This approach indicates a convenient means of determining the refractive indices and surface mass densities of mesothick organic layers proteins on solid supports. 相似文献
219.
The prediction of mechanical properties of injection moulding parts by vacuum casting 总被引:1,自引:0,他引:1
The behaviour of vacuum cast prototypes and injection moulding parts in mechanical tests was compared. The mechanical tests were made using real production parts as references. Distinct correlations were found between vacuum cast prototypes and injection moulding parts. In this light, vacuum cast prototypes can be used for the evaluation of injection moulding products with certain limitations. Vacuum casting is best suited for the evaluation of such mechanical properties of injection moulding products as tensile, flexural and compression strength, while impact strength is the property that is most difficult to evaluate. 相似文献
220.
To ensure the reliability of results, analytical laboratories require a continuous qualitycontrol program which must take account of both systematic and random errors. Analyses of reference materials can be used to estimate systematic errors but estimates of random errors (precision) tend to be optimistic, mainly because reference materials cannot be put through the whole analytical process (e.g., primary sampling is often a major source of error). Estimates of precision must be based on routine samples. If duplicate determinations are done on routine samples, the precision can be estimated reliably. Within the optimum concentration range of analytical method (usually starting from 5-10 times the detection limit), the relative standard deviation (sr can be regarded as being almost constant or independent of concentration. The precision can then be estimated by first calculating the sr value of each pair of results. Individually, these are not reliable estimates of the true sr, but they can be regarded as independent measurements of the same sr and so can be pooled to obtain a more reliable estimate of precision with the number of duplicates as the degrees of freedom. The applicabiilty of the method is tested on soil, rock and ore samples. 相似文献
|