全文获取类型
收费全文 | 440篇 |
免费 | 9篇 |
国内免费 | 3篇 |
专业分类
化学 | 252篇 |
晶体学 | 4篇 |
力学 | 6篇 |
数学 | 64篇 |
物理学 | 126篇 |
出版年
2022年 | 6篇 |
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 8篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 7篇 |
2013年 | 20篇 |
2012年 | 26篇 |
2011年 | 25篇 |
2010年 | 11篇 |
2009年 | 16篇 |
2008年 | 17篇 |
2007年 | 11篇 |
2006年 | 21篇 |
2005年 | 17篇 |
2004年 | 9篇 |
2003年 | 12篇 |
2002年 | 8篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 9篇 |
1998年 | 5篇 |
1997年 | 8篇 |
1996年 | 12篇 |
1995年 | 12篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1977年 | 5篇 |
1975年 | 3篇 |
1972年 | 4篇 |
1969年 | 5篇 |
1933年 | 3篇 |
1907年 | 3篇 |
1888年 | 5篇 |
1885年 | 3篇 |
排序方式: 共有452条查询结果,搜索用时 0 毫秒
41.
42.
C. L. Reimer und W. Will 《Fresenius' Journal of Analytical Chemistry》1890,29(1):723-724
Ohne Zusammenfassung 相似文献
43.
William R. Dolbier Jr. Yian Zhai Wei Xu Will Wheelus Florian Dulong Efram Goldberg Ion Ghiviriga Merle A. Battiste 《Journal of fluorine chemistry》2008,129(12):1133-1138
When 4-nitro-AF4 is treated with nucleophiles such as alkoxides and cyanide, a novel ring opening, cyclophane destroying reaction is observed whereby, via an SNAr mechanism, the nucleophile attacks the bridgehead aryl carbon vicinal to the nitro group with subsequent aryl-CF2 bond cleavage. 相似文献
44.
45.
Graham Smith Geoffrey D. Will Gregory J. Wilson 《Journal of chemical crystallography》2010,40(3):248-252
Abstract
The crystal structure of the modified unsymmetrically N,N′-substituted viologen chromophore, N-ethyl-N′-(2-phosphonoethyl)-4,4′-bipyridinium dichloride 0.75 hydrate (1) has been determined. Crystals are triclinic, space group P−1 with Z = 2 in a cell with a = 7.2550(1), b = 13.2038(5), c = 18.5752(7) Å, α = 86.495(3), β = 83.527(2), γ = 88.921(2)°. The two independent but pseudo-symmetrically related cations in the asymmetric unit form one-dimensional hydrogen-bonded chains through short homomeric phosphonic acid O–H···O links [2.455(4), 2.464(4) Å] while two of the chloride anions are similarly strongly linked to phosphonic acid groups [O–H···Cl, 2.889(4), 2.896(4) Å]. The other two chloride anions together with the two water molecules of solvation (one with partial occupancy) form unusual cyclic hydrogen-bonded bis(Cl···water) dianion units which lie between the layers of bipyridylium rings of the cation chain structures with which they are weakly associated. 相似文献46.
Shu L Baumbach RE Janoschek M Gonzales E Huang K Sayles TA Paglione J O'Brien J Hamlin JJ Zocco DA Ho PC McElroy CA Maple MB 《Physical review letters》2011,106(15):156403
X-ray diffraction, electrical resistivity, magnetic susceptibility, and specific heat measurements on Ce(1-x)Yb(x)CoIn5 (0≤x≤1) reveal that many of the characteristic features of the x=0 correlated electron state are stable for x≤0.775 and that phase separation occurs for x>0.775. The stability of the correlated electron state is apparently due to cooperative behavior of the Ce and Yb ions, involving their unstable valences. Low-temperature non-Fermi liquid behavior is observed and varies with x, even though there is no readily identifiable quantum critical point. The superconducting critical temperature T(c) decreases linearly with x towards 0 K as x→1, in contrast with other HF superconductors where T(c) scales with T(coh). 相似文献
47.
G. Murtaza Rai M.A. IqbalI.G. Will Z.C. Huang 《Journal of magnetism and magnetic materials》2011,323(24):3239-3245
The samarium doping zinc oxide (Zn1-xSmxO) with (x=0.0, 0.04, 0.05 and 0.17) polycrystalline thin films have been deposited on n-Si(1 0 0) substrate using thermal evaporation technique. Ceramic targets for deposition were prepared by the standard solid-state reaction method and sintered in nitrogen atmospheres. X-ray diffraction and scanning electron microscopy analyses show that the bulk and films features reveal wurtzite crystal structure with a preferential (1 0 1) crystallographic orientation and grows as hexagonal shape grains. According to the results of the Hall effect measurements, all the films show p-type conductivity, possibly a result of nitrogen incorporation into the Sm-doped ZnO samples. Magnetic measurements show that ferromagnetic behavior depends on the Sm3+ concentration. For a film with lower Sm2O3 contents (x=0.04), a phenomenon of paramagnetism has been observed. While, with further increase of Sm3+ contents (x=0.05) the ferromagnetic behavior has been observed at room temperature. However, at higher doping content of Sm3+, the ferromagnetic behavior was suppressed. The decrease of ferromagnetism with increasing doping concentration demonstrates that ferromagnetism observed at room temperature is an intrinsic property of Zn1-xSmxO films. 相似文献
48.
49.
Will J. Merry Gabriel P. Paternain 《Journal of Fixed Point Theory and Applications》2011,10(1):87-111
In this note we study two index questions. In the first we establish the relationship between the Morse indices of the free
time action functional and the fixed time action functional. The second is related to Rabinowitz Floer homology. Our index
computations are based on a correction term which is defined as follows: around a nondegenerate Hamiltonian orbit lying in
a fixed energy level a well-known theorem says that one can find a whole cylinder of orbits parametrized by the energy. The
correction term is determined by whether the periods of the orbits are increasing or decreasing as one moves up the orbit
cylinder. We also provide an example to show that, even above the Ma?é critical value, the periods may be increasing thus
producing a jump in the Morse index of the free time action functional in relation to the Morse index of the fixed time action
functional. 相似文献
50.
L. Funke J. Döring P. Kemnitz P. Ojeda R. Schwengner E. Will G. Winter A. Johnson L. Hildingsson Th. Lindblad 《Zeitschrift für Physik A Hadrons and Nuclei》1986,323(2):127-137
Projectile and targetK-vacancy production probabilities in 4.6-, 5.8- and 7.3-MeV/a.m.u. U+U and U+Pb collisions are reported for impact parameters between 10 and 85 fm. These probability measurements are compared with available theory. 相似文献