全文获取类型
收费全文 | 1544篇 |
免费 | 46篇 |
国内免费 | 3篇 |
专业分类
化学 | 1284篇 |
晶体学 | 15篇 |
力学 | 18篇 |
数学 | 101篇 |
物理学 | 175篇 |
出版年
2023年 | 5篇 |
2021年 | 7篇 |
2020年 | 8篇 |
2019年 | 18篇 |
2018年 | 20篇 |
2017年 | 7篇 |
2016年 | 36篇 |
2015年 | 31篇 |
2014年 | 41篇 |
2013年 | 80篇 |
2012年 | 70篇 |
2011年 | 84篇 |
2010年 | 56篇 |
2009年 | 33篇 |
2008年 | 82篇 |
2007年 | 63篇 |
2006年 | 80篇 |
2005年 | 70篇 |
2004年 | 74篇 |
2003年 | 92篇 |
2002年 | 75篇 |
2001年 | 22篇 |
2000年 | 54篇 |
1999年 | 24篇 |
1998年 | 18篇 |
1997年 | 24篇 |
1996年 | 26篇 |
1995年 | 23篇 |
1994年 | 22篇 |
1993年 | 21篇 |
1992年 | 20篇 |
1991年 | 18篇 |
1990年 | 16篇 |
1989年 | 6篇 |
1988年 | 15篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 20篇 |
1984年 | 22篇 |
1983年 | 9篇 |
1982年 | 20篇 |
1981年 | 22篇 |
1980年 | 24篇 |
1979年 | 26篇 |
1978年 | 22篇 |
1977年 | 13篇 |
1976年 | 14篇 |
1974年 | 8篇 |
1973年 | 10篇 |
1968年 | 5篇 |
排序方式: 共有1593条查询结果,搜索用时 15 毫秒
131.
Onishi Yoshito Seo Yoshiho Matsuoka Masaoki Serikawa Shigeru Tsugane Ken 《Optical Review》2022,29(5):409-419
Optical Review - Machine vision system has great significance for the automatic inspection to enhance unclear defects. For the purpose of the improvement of the recognition accuracy in the... 相似文献
132.
133.
The relationship between the flexural wave velocity and the excited vibration mode of a thin cylindrical shell is investigated. The natural frequency corresponding to the vibration mode is obtained as the solution of characteristic equation of thin cylindrical shell. However, all of these vibration modes are not excited actually. To estimate the excited vibration mode, the concept of "modified bending stiffness" is introduced, and the influence of each stress component upon the modified bending stiffness is analyzed. The excited mode is theoretically discriminated from the nonexcited mode based on the smallness of this modified bending stiffness. The validity of our theory is confirmed by an excellent agreement between theoretical and experimental results on flexural wave velocity. 相似文献
134.
Statistical properties of fluctuations of pressure drop across the gas–liquid dispersions on the tray were analyzed using a 215 mm dia. three plates column with different trays. Hydrodynamic regimes of the froth were characterized in terms of the statistical properties evaluated. It was proved that the on-line estimation of the flow behavior of the froth was possible on the basis of the pattern recognition of the power spectral density function of the pressure fluctuations. The time-domain stochastic models for fluctuations of the pressure drop were identified so as to be available for its forecast and simulation. 相似文献
135.
We revisit the EPR problem and make clear what is a correct comprehension of its problem. When one applies the quantum mechanics correctly, it will be shown that there is no paradox. According to these lines of thought, a quantum teleportation scheme without resort to the von Neumann projection postulate is presented. 相似文献
136.
137.
An imaging method for partially coherent objects is proposed by the aid of the propagation law of mutual intensity, and it can be reduced to principles used in holography and radio astronomy if the coherence reaches the both extremes, i.e., perfect coherence and complete incoherence, respectively. 相似文献
138.
James R. Evans Shigeru Tsubakitani 《The Journal of the Operational Research Society》1993,44(2):175-184
We investigate the application of Benders' partitioning to a mixed integer programming formulation of the segregated storage problem. The dual subproblem reduces to an efficiently-solvable network flow problem. This approach is compared empirically to Neebe's multiplier adjustment procedure. Benders' procedure is shown to be computationally effective for an important class of practical applications having high demand-to-capacity ratios and fewer products than compartments. 相似文献
139.
Shingo Sato Hironobu Kumagai Shigeru Matsuba Toshihiro Kumazawa Jun-Ichi Onodera Masanobu Suzuki 《Journal of heterocyclic chemistry》1999,36(5):1345-1347
A flavanone, in which a hydroxyl group at the 5-position was protected with a methyl group, converted to the corresponding 5-methoxy-2-phenyl-4-quinolone via flavylium salt under mild conditions. Flavanone-O-rhamnoglucoside, naringin, was also converted to 5-methoxy-2-phenyl-4-quinolon-7-O-rhamnoglucoside in the same way in an overall 25% yield. 相似文献
140.
Shigeru Yabumoto Kiyoshi Ishii Koichiro Arita 《Journal of polymer science. Part A, Polymer chemistry》1969,7(7):1577-1588
Copolymerization of acrylonitrile with styrene spontaneously occurred on addition of zinc chloride without addition of any other radical initiator. The composition of the copolymer approached that of strictly alternating copolymer as zinc chloride added to the copolymerization system increased. The significance of the apparent monomer reactivity ratios of this copolymerization system was studied from a kinetic point of view, and it was shown that the monomer sequence distribution is indicated by the apparent monomer reactivity ratios. Further, equations which represent the relation between the apparent monomer reactivity ratios and Q,e values at a given salt concentration were derived. These equations reasonably accounted for the decrease of the apparent monomer reactivity ratios of the copolymerization of acrylonitrile with styrene in the presence of zinc chloride and the behavior of the other acrylonitrile copolymerization systems in the presence of zinc chloride. The initiation step of the spontaneous radical copolymerization of acrylonitrile with styrene in the presence of zinc chloride was explained by a cross-initiation mechanism. 相似文献