全文获取类型
收费全文 | 1670篇 |
免费 | 46篇 |
国内免费 | 10篇 |
专业分类
化学 | 1277篇 |
晶体学 | 18篇 |
力学 | 21篇 |
数学 | 121篇 |
物理学 | 289篇 |
出版年
2023年 | 6篇 |
2022年 | 15篇 |
2021年 | 10篇 |
2020年 | 15篇 |
2019年 | 23篇 |
2018年 | 17篇 |
2017年 | 17篇 |
2016年 | 34篇 |
2015年 | 37篇 |
2014年 | 37篇 |
2013年 | 80篇 |
2012年 | 89篇 |
2011年 | 96篇 |
2010年 | 60篇 |
2009年 | 61篇 |
2008年 | 101篇 |
2007年 | 97篇 |
2006年 | 92篇 |
2005年 | 95篇 |
2004年 | 105篇 |
2003年 | 74篇 |
2002年 | 75篇 |
2001年 | 35篇 |
2000年 | 30篇 |
1999年 | 18篇 |
1998年 | 17篇 |
1997年 | 15篇 |
1996年 | 23篇 |
1995年 | 17篇 |
1994年 | 23篇 |
1993年 | 22篇 |
1992年 | 16篇 |
1991年 | 16篇 |
1990年 | 11篇 |
1989年 | 18篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 11篇 |
1985年 | 21篇 |
1984年 | 15篇 |
1983年 | 18篇 |
1982年 | 9篇 |
1981年 | 16篇 |
1980年 | 13篇 |
1979年 | 14篇 |
1978年 | 10篇 |
1977年 | 18篇 |
1976年 | 7篇 |
1975年 | 15篇 |
1974年 | 11篇 |
排序方式: 共有1726条查询结果,搜索用时 0 毫秒
131.
132.
T.Nakagawa M.Kidera Y.Higurasi J.Ohnishi T.Kageyama T.Aihara A.Goto Y.Yano 《中国物理 C》2007,31(Z1):133-136
We measured the main plasma parameters(density of electron,temperature of electron and ion confinement time)and beam intensity of various heavy ions as a function of B_(min).The B_(min) strongly affects the field gradient at the resonance zone,consequently the plasma parameters and beam intensity are changed. Based on these experimental results,we started to construct new 18GHz ECRIS and make a detailed design of the 28GHz SC-ECRIS for RIKEN RI beam factory project. 相似文献
133.
134.
Nam‐Ho You Tomoya Higashihara Shinji Ando Mitsuru Ueda 《Journal of polymer science. Part A, Polymer chemistry》2010,48(12):2604-2609
New sulfur‐containing polymers with high‐refractive indices and low birefringences have been developed as UV‐curable high‐refractive polymer resins. The polymers derived from 2,7‐bis[(2‐acryloylethyl)sulfanyl]thianthrene (2,7‐BAST) and 4,4′‐bis[(acryloyloxyethylthio)diphenylsulfide (4,4′‐BADS) were prepared by photopolymerization under UV irradiation. Transparent UV‐cured films were obtained in both cases. Both polymers showed good thermal stability, such as a 5% weight‐loss temperature at 355 °C under nitrogen and glass transition temperatures (Tg) in the range of 94–143 °C. They also showed high‐refractive indices of 1.6531 and 1.6645 at 632.8 nm and low birefringences of 0.0039 and 0.0069 in addition to high transparency in the visible region. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2604–2609, 2010 相似文献
135.
The 7-endo Friedel-Crafts cyclization of arylpropyl vinyloxiranes was found to proceed regio- and stereoselectively to afford polyfunctional seven-membered carbocycles in excellent yields. 相似文献
136.
137.
PVTx relationships and solid-liquid equilibria for the m-xylene-p-xylene system under high pressures
PVTx relationships of the m-xylene-p-xylene system have been measured with a glass piezometer at 283.15 and 298.15 K and pressures up to 200 MPa, or up to the point of solidification of m-xylene where this occurred at a lower pressure. Freezing pressures of m-xylene were observed as a discontinuity in the volume at increasing pressure. Approximate solid-liquid equilibria under high pressures were obtained from the freezing pressure measurement. The Carnahan-Starling-van der Waals (CS-vdW) equation of state was used to correlate the PVTx data. The solid-liquid equilibria under high pressures were calculated with the CS-vdW equation of state for the liquid phase and a simple equation of state for the solid phase. In order to test the validity of the calculation method, the solid-liquid equilibrium relationships of the benzene-cyclohexane system were also calculated. It was found that the solid molar volume should be treated as a function of temperature and/or pressure to fit the experimental data. 相似文献
138.
Tetsuya Yuasa Shinji Tanosaki Yoshiaki Sasaki Michiaki Takagi Akira Ishikawa Hiroshi Taniguchi Balasigamani Devaraj Takao Akatsuka 《Analytical sciences》2002,18(12):1329-1333
The coherent detection imaging (CDI) method uses the optical heterodyne detection technique. CW and single frequency lasers having long coherence lengths are used to exploit the maximum advantages of heterodyne detection, such as high directionality, selectivity and sensitivity. The CDI method based on optical heterodyne detection enables selective filtering of the directional coherence-retaining emergent photons, which leads to image reconstruction from projections, similar to X-ray computed tomography (CT). So far we have demonstrated the advantages and capabilities of the measurement technique for transillumination optical computed tomography in biomedicine. Here, we investigate the fundamental imaging properties of CDI method, such as its high directionality and quantitativeness, with preliminary physical phantom experiments. The results show that the CDI method satisfies the requirements for CT reconstruction under the first order approximation, and enables quantitative measurements in the sense that the relationship between estimated and actual concentration retains a satisfactory linearity. 相似文献
139.
140.
Masafumi Yano Yorichika Okino Yuji Ichihara Masakazu Tatsumi Munetaka Oyama Kazunobu Sato Takeji Takui 《Polyhedron》2009,28(9-10):1764-1767
Three highly π-extended tetraaryl-1,3-phenylenediamines for charged high-spin molecular systems were successfully synthesized using Suzuki coupling. Their electrochemical and spectroscopic properties were also examined. They showed blue fluorescence. The dications derived from highly π-extended tetraaryl-1,3-phenylenediamines were generated and characterized by electron transfer stopped-flow method. 相似文献