全文获取类型
收费全文 | 130987篇 |
免费 | 1776篇 |
国内免费 | 490篇 |
专业分类
化学 | 72782篇 |
晶体学 | 2148篇 |
力学 | 5061篇 |
综合类 | 6篇 |
数学 | 12889篇 |
物理学 | 40367篇 |
出版年
2016年 | 1450篇 |
2015年 | 1165篇 |
2014年 | 1503篇 |
2013年 | 5033篇 |
2012年 | 3729篇 |
2011年 | 4791篇 |
2010年 | 2959篇 |
2009年 | 2748篇 |
2008年 | 4280篇 |
2007年 | 4352篇 |
2006年 | 4393篇 |
2005年 | 4281篇 |
2004年 | 3732篇 |
2003年 | 3340篇 |
2002年 | 3260篇 |
2001年 | 3676篇 |
2000年 | 2768篇 |
1999年 | 2265篇 |
1998年 | 1970篇 |
1997年 | 1941篇 |
1996年 | 1898篇 |
1995年 | 1863篇 |
1994年 | 1600篇 |
1993年 | 1594篇 |
1992年 | 1810篇 |
1991年 | 1794篇 |
1990年 | 1732篇 |
1989年 | 1727篇 |
1988年 | 1727篇 |
1987年 | 1718篇 |
1986年 | 1625篇 |
1985年 | 2186篇 |
1984年 | 2303篇 |
1983年 | 1922篇 |
1982年 | 2246篇 |
1981年 | 2073篇 |
1980年 | 2115篇 |
1979年 | 2081篇 |
1978年 | 2214篇 |
1977年 | 2127篇 |
1976年 | 2141篇 |
1975年 | 2075篇 |
1974年 | 1915篇 |
1973年 | 2140篇 |
1972年 | 1300篇 |
1971年 | 995篇 |
1970年 | 917篇 |
1969年 | 932篇 |
1968年 | 1062篇 |
1967年 | 1105篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
M. Brando N. Büttgen V. Fritsch J. Hemberger H. Kaps H.-A. Krug von Nidda M. Nicklas K. Pucher W. Trinkl A. Loidl E.W. Scheidt M. Klemm S. Horn 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,25(3):289-298
We present susceptibility, microwave resistivity, NMR and heat-capacity results for Li1-xZnx(V1-yTiy)2O4 with 0 ?
x
? 0.3 and 0 ?
y
? 0.3. For all doping levels the susceptibility curves can be fitted with a Curie-Weiss law. The paramagnetic Curie-Weiss temperatures
remain negative with an average value close to that of the pure compound Θ≈ - 36 K. Spin-glass anomalies are observed in the susceptibility, heat-capacity and NMR measurements for both type of dopants.
From the temperature dependence of the spin-lattice relaxation rate we found critical-dynamic behavior in the Zn doped compounds
at the freezing temperatures. For the Ti-doped samples two successive freezing transitions into disordered low-temperature
states can be detected. The temperature dependence of the heat capacity for Zn-doped compounds does not resemble that of canonical
spin glasses and only a small fraction of the total vanadium entropy is frozen at the spin-glass transitions. For pure LiV2O4 the spin-glass transition is completely suppressed. The temperature dependence of the heat capacity for LiV2O4 can be described using a nuclear Schottky contribution and the non-Fermi liquid model, appropriate for a system close to
a spin-glass quantum critical point. Finally an (
x
/
y
,
T
)-phase diagram for the low-doping regime is presented.
Received 16 March 2001 and Received in final form 30 October 2001 相似文献
92.
93.
S. J. Cheng W. Sheng P. Hawrylak S. Raymond S. Studenikin A. Sachrajda Z. Wasilewski A. Babinski M. Potemski G. Ortner M. Bayer 《Physica E: Low-dimensional Systems and Nanostructures》2004,21(2-4):211
We present results of calculations and experiments on electron–hole complexes in InGaAs/GaAs self-assembled quantum dots in high magnetic field (B). Due to hidden symmetries, the chemical potential of an N-exciton system at special B fields becomes insensitive to the exciton number as well as the magnetic field. This results in plateau regions of high intensity in measured magneto-PL spectrum. Theoretical calculations using exact diagonalization techniques successfully explain the measured magneto-photoluminescence spectrum with B fields up to 28 T. 相似文献
94.
Jeroen J. L. M. Cornelissen W. Sander Graswinckel Alan E. Rowan Nico A. J. M. Sommerdijk Roeland J. M. Nolte 《Journal of polymer science. Part A, Polymer chemistry》2003,41(11):1725-1736
The conformational properties of polymers derived from isocyanodipeptides have been investigated with a combination of model calculations, X‐ray diffraction, and circular dichroism spectroscopy. Depending on the configuration of the side chains, defined arrays of hydrogen bonds along the polymeric backbone are formed. This leads to a well‐defined conformation as, for example, expressed in the formation of lyotropic liquid‐crystalline phases and increased helical stability. Upon the disruption of the hydrogen bonds by a strong acid, a less well‐defined macromolecular conformation is observed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1725–1736, 2003 相似文献
95.
M Lepère R Gobeille V.Malathy Devi M.A.H Smith B Aoaeh A.W Mantz 《Journal of Molecular Spectroscopy》2004,224(1):7-12
We have analyzed the methyl fluoride RQ(J,0)Q branch lines located near 1475 cm−1 using a simultaneous multi-spectrum fitting technique. In this analysis we have used previously recorded diode-laser data in which we collected many data points covering only one or two Q branch lines in a particular run. The analysis consists of simultaneously fitting 57 spectra collected with numerous pressure and path length conditions for all absorption lines. The data are concatenated to create one continuous spectrum of the Q branch. We have determined the intensity and self-broadened widths at 296 K for 23 RQ(J,0) lines. 相似文献
96.
M. Stangl V. Dittel J. Acker V. Hoffmann W. Gruner S. Strehle K. Wetzig 《Applied Surface Science》2005,252(1):158-161
At room temperature electroplated copper layers exhibit changes in resistivity, residual stress, and microstructure. This process, known as self-annealing, is intimately linked to the release of organic impurities, which stem from the incorporation of organic additives into the Cu layer in the course of the electroplating process. The behavior of these impurities during self-annealing, represented by the carbon content, could be detected by analytical radio frequency glow discharge optical emission spectrometry (GD-OES) and carrier gas hot extraction (CGHE). The precondition of a quantitative determination is a surface cleaning procedure to remove adsorbed organics from the copper surface. It was observed that at first almost all impurities have to leave the Cu metallization before an accelerated abnormal grain growth can start. The small amount of remaining organic species after self-annealing could be quantified by both examination techniques, GD-OES and CGHE. 相似文献
97.
W. Hampe 《Fresenius' Journal of Analytical Chemistry》1885,24(1):588-590
Ohne Zusammenfassung 相似文献
98.
99.
We compute neutral Higgs and Z0-boson couplings to quarks in a model with three quark-lepton families and one mirror family. Mixing between ordinary and mirrorquarks leads to flavour-changing couplings which are negligible for the known quarks. However, t-quark couplings are sizeable and the branching ratio for the decay
can be as large as 10−4. 相似文献
100.
Blood serum samples were irradiated by monochromatic synchrotron radiation (15 keV) and by 2.4-MeV protons to compare their performance for the detection of trace elements by x-ray fluorescence (XRF) spectrometry. Absolute concentration assignment was based on the addition of an internal standard and on a method which uses the incoherent and coherent radiation as a flux monitor of the incoming beam. Preliminary experiments with a synchrotron XRF microprobe are reported. 相似文献