全文获取类型
收费全文 | 3043篇 |
免费 | 52篇 |
国内免费 | 12篇 |
专业分类
化学 | 1926篇 |
晶体学 | 23篇 |
力学 | 74篇 |
数学 | 266篇 |
物理学 | 818篇 |
出版年
2020年 | 28篇 |
2019年 | 25篇 |
2016年 | 37篇 |
2015年 | 29篇 |
2014年 | 49篇 |
2013年 | 97篇 |
2012年 | 88篇 |
2011年 | 112篇 |
2010年 | 85篇 |
2009年 | 62篇 |
2008年 | 120篇 |
2007年 | 87篇 |
2006年 | 118篇 |
2005年 | 69篇 |
2004年 | 74篇 |
2003年 | 51篇 |
2002年 | 88篇 |
2001年 | 64篇 |
2000年 | 69篇 |
1999年 | 59篇 |
1998年 | 56篇 |
1997年 | 51篇 |
1996年 | 60篇 |
1995年 | 76篇 |
1994年 | 58篇 |
1993年 | 58篇 |
1992年 | 50篇 |
1991年 | 54篇 |
1990年 | 45篇 |
1989年 | 40篇 |
1988年 | 49篇 |
1987年 | 46篇 |
1986年 | 37篇 |
1985年 | 53篇 |
1984年 | 47篇 |
1983年 | 39篇 |
1982年 | 35篇 |
1981年 | 55篇 |
1980年 | 53篇 |
1979年 | 38篇 |
1978年 | 48篇 |
1977年 | 39篇 |
1976年 | 46篇 |
1975年 | 35篇 |
1974年 | 47篇 |
1973年 | 49篇 |
1971年 | 24篇 |
1970年 | 39篇 |
1968年 | 25篇 |
1967年 | 31篇 |
排序方式: 共有3107条查询结果,搜索用时 31 毫秒
1.
An effective residual interaction between particles and holes for shell model calculations around 208Pb, derived from the interaction between free nucleons, is compared with the measured properties of proton-hole neutron states
in 208Tl and the interaction between proton holes is adjusted to newly measured level energies in 206Hg. These interaction elements are particularly relevant for neutron-rich nuclei. The adjustment of two mixing elements reproduces
the known γ-decay data in 208Tl.
Received: 2 April 2002 / Accepted: 2 May 2002 相似文献
2.
Stefan A. Maier 《Optical and Quantum Electronics》2006,38(1-3):257-267
The controlled squeezing of electromagnetic energy into nanometric volumes via surface plasmon-polariton excitations in plasmonic nanoresonators is analyzed using the concept of an effective electromagnetic mode volume V eff, while taking careful account of the plasmon-polariton dispersion and the electromagnetic energy stored in the metal. Together with the quality factor Q of the cavity resonance, this enables a comparison with dielectric optical cavities, where V eff is limited by diffraction. For a Fabry–Perot type planar metallic cavity, a one-dimensional analytic model as well as a three-dimensional finite-difference time-domain simulation reveal that V eff is not bounded by diffraction, and that Q/V eff increases for decreasing cavity size. In this picture, matter–plasmon interactions can be quantified in terms of Q and V eff, and a resonant cavity model for the enhancement of spontaneous Raman scattering is presented. 相似文献
3.
The concept of strong interactions need not be limited to the sector of physics taken by QCD. While this domain is investigated by RHIC, LHC will be able to probe potential new strong interactions simultaneously: Finding the precise mechanism for electroweak symmetry breaking is one of the prime problems of physics. Intricately linked to this point is the question after the true nature or even the existence of the Higgs boson. Here, we present stronly interacting theories providing an explanation for the hierarchy problem and leading to a light composite Higgs boson, favoured by experimental data. Our variation of the standard model is consistent with precision data. We achieve this accordance by using technifermions in a higher representation of their gauge group. Anomaly conditions require at least one extra lepton family for some of the theories whereby they contain a natural dark matter candidate. We can accurately determine the masses of said leptons from experimental data. 相似文献
4.
5.
Using ultra-high vacuum scanning tunneling microscopy (UHV-STM), we show that copper-phthalocyanine (CuPc) grows in a well ordered manner on hydrogen passivated vicinal silicon surfaces. CuPc grows one-dimensionally parallel to the monatomic steps on the vicinal silicon surface. Surprisingly, elongated clusters of the CuPc parallel to the step directions are formed even on the middle of the terraces well away from the step edges. The one-dimensional growth mode continues even after the full monolayer coverage on the substrate which results in strongly oriented growth mode of a thin film of CuPc on the vicinal silicon surfaces. 相似文献
6.
Hamid R. Memarian Mohammad Bagheri Dietrich D?pp 《Monatshefte für Chemie / Chemical Monthly》2004,42(3):833-838
In continuation of previous work some novel 3,5-diacetyl-1,4-dihydropyridine derivatives were synthesized and their photochemical behavior was studied under oxygen and argon atmosphere. Oxidation of the dihydropyridine ring and formation of pyridine derivatives was the result of the reaction. The presence of oxygen affects not only on the rate of oxidation, but also the formation of some unidentified by-products was observed on irradiation under this atmosphere. 相似文献
7.
B. Griepink E. A. Maier P. Quevauviller H. Muntau 《Fresenius' Journal of Analytical Chemistry》1991,339(9):599-603
Summary The Community Bureau of Reference (BCR) has undertaken the production of a wide range of certified reference materials (CRMs) for the improvement of accuracy and measurement harmony in various areas of concern at European Community level. This paper provides an overview of the sectors of the BCR-programme in the field of environment i.e. for water systems (water, sediment, biota), soil analysis (soil, fertiliser, waste), plant analysis (aquatic and terrestrial plants), analysis related to animals (e.g. muscle or liver) or man (e.g. industry and food). 相似文献
8.
9.
10.
Robert S. Maier 《Random Structures and Algorithms》1991,2(4):379-420
We analyze the performance of a prototypical scheme for shared storage allocation: two initially empty stacks evolving in a contiguous block of memory of size m. We treat the case in which the stacks are more likely to shrink than grow, but with the probabilities of insertion and deletion allowed to depend arbitrarily on stack height as a fraction of m. New results are obtained on the m → ∞ asymptotics of the stack collision time, and of the final stack heights. The results of Wentzell and Freidlin on the large deviations of Markov chains are used, and the relation of their formalism to the Hamiltonian formulation of classical mechanics is emphasized. Certain results on higher-order asymptotics follow from WKB expansions. 相似文献