全文获取类型
收费全文 | 2001篇 |
免费 | 43篇 |
国内免费 | 8篇 |
专业分类
化学 | 1515篇 |
晶体学 | 15篇 |
力学 | 8篇 |
数学 | 71篇 |
物理学 | 443篇 |
出版年
2022年 | 9篇 |
2021年 | 11篇 |
2020年 | 20篇 |
2019年 | 18篇 |
2018年 | 18篇 |
2017年 | 18篇 |
2016年 | 28篇 |
2015年 | 22篇 |
2014年 | 34篇 |
2013年 | 121篇 |
2012年 | 92篇 |
2011年 | 115篇 |
2010年 | 73篇 |
2009年 | 78篇 |
2008年 | 110篇 |
2007年 | 124篇 |
2006年 | 110篇 |
2005年 | 97篇 |
2004年 | 92篇 |
2003年 | 80篇 |
2002年 | 69篇 |
2001年 | 46篇 |
2000年 | 31篇 |
1999年 | 26篇 |
1998年 | 22篇 |
1997年 | 17篇 |
1996年 | 21篇 |
1995年 | 19篇 |
1994年 | 27篇 |
1993年 | 19篇 |
1992年 | 23篇 |
1991年 | 24篇 |
1990年 | 21篇 |
1989年 | 21篇 |
1988年 | 20篇 |
1987年 | 16篇 |
1986年 | 21篇 |
1985年 | 34篇 |
1984年 | 31篇 |
1983年 | 11篇 |
1982年 | 23篇 |
1981年 | 24篇 |
1980年 | 32篇 |
1979年 | 27篇 |
1978年 | 20篇 |
1977年 | 15篇 |
1976年 | 16篇 |
1975年 | 20篇 |
1974年 | 15篇 |
1973年 | 25篇 |
排序方式: 共有2052条查询结果,搜索用时 62 毫秒
51.
T. Kubo M. Belkacem V. Latora A. Bonasera 《Zeitschrift für Physik A Hadrons and Nuclei》1995,352(2):145-148
Intermittent behaviour of fragment multiplicity distributions in the nuclear liquid-gas phase transition is studied in terms of the droplet model of Fisher. The anomalous fractal dimensions are compared with data on heavy ion reactions and classical molecular dynamics simulations. A signature of the transition in the anomalous fractal dimensions is shown.We thank Profs. S. Ayik, M. Di Toro and V. Kondratyev for discussions. One of us (T.K.) acknowledges the support of INFN-LNS. 相似文献
52.
53.
H. Kagetsu N. Shioyasu N. Fukunishi M. K. Kubo Y. Sakai T. Tominaga K. Nishiyama K. Nagamine 《Hyperfine Interactions》1994,84(1):517-520
We have carried out SR experiments on [Co(NH3)6]Cl3 and [Co(ND3)6]Cl3. At 293 K, all the muons implanted into the complexes were in the diamagnetic state. The observed Gaussian-type muon spin relaxation function proved that the internal magnetic field was caused by nuclear dipole moments of the atoms in the complexes. In addition, another exponential-type muon spin relaxation function was observed in [Co(ND3)6]Cl3 below 50 K. 相似文献
54.
55.
Transition of the radial electric field by electron cyclotron heating in the CHS heliotron/torsatron
56.
Tetsuo Suami Hiroaki Sasai Kazuhiro Matsuno Nobuo Suzuki Yoshimasa Fukuda Osamu Sakanaka 《Tetrahedron letters》1984,25(40):4533-4536
Tunicamycins and their eight analogs have been synthesized by condensation of a N-acetyl-D-glucosamine derivative and an anomeric chloride of tunicaminyl uracil, followed by deprotections and N-acylation. 相似文献
57.
Hosoya K Hira N Watabe Y Tanaka N Kubo T Kaya K 《Analytical and bioanalytical chemistry》2004,380(2):343-345
Thiacalix[4]arene (5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrahydroxy-2,8,14,20-tetrathiacalix[4]arene) is an amphiphilic molecule comprising four p-tert-butylphenol-like groups ortho-linked by single sulfur atoms. This molecule has a high electron density area owing to the close proximity of the hydroxyl groups and sulfur atoms. We studied the applicability of this interesting compound as a selector for high-performance liquid chromatography (HPLC) thereby presumably exploiting this feature. Firstly, uniformly sized polymer particles were prepared by using a multi-step swelling and polymerization method with ethylene glycol dimethacrylate (EDMA) as a cross-linker. Methacrylic acid (MAA) was introduced onto the surface of the resulting polymer particles through a new modification method. Thiacalix[4]arene was chemically bonded through the MAA group by using 1,4-dibromobutane as a spacer to reduce steric hindrance around the MAA and the polymer particle itself. The performance of the prepared polymer-based thiacalix[4]arene-modified stationary phase was evaluated with HPLC. Specific chromatographic retention behavior was observed for catechol relative to positional isomers of xylene, cresol, and benzene-diol. Catecholamine and catechol showed specific chromatographic retention behavior. 相似文献
58.
We have plotted electropherograms in capillary zone electrophoresis (CZE) as a function of the quantity of electric charge (Q) in order to eliminate the dependency of the analyte peak areas, as well as that of the migration times, upon both the capillary temperature and the applied voltage. The procedure is based on an idea of a migration index (MI) and an adjusted migration index (AMI) which were originally proposed by Lee and Yeung. The value of Q is measured accurately and calculated easily because it is given by a product of the electrophoretic current and the migration times, where the index MI is derived by dividing the value of Q by the effective volume of the capillary. By calculating the CZE peak area from the newly plotted electropherogram, improvement in precision in quantitative analysis is expected. Concerning AMI, careful treatment is required in its application to analyte peaks whose migration time is close to that of the neutral marker. Experimental data and discussions concerning the migration indices are presented. 相似文献
59.
Miwa Kubo 《Tetrahedron letters》2006,47(12):1927-1931
We synthesized a peptidocalix[4]arene library consisting of 1000 members that was suitable for peptide recognition in aqueous media. Some peptidocalix[4]arenes in the library were host molecules for guest peptides. Electrostatic interaction between the host and guest molecules was the most important factor for binding in aqueous media. 相似文献
60.
Large-scale separation of metallic and semiconducting single-walled carbon nanotubes 总被引:6,自引:0,他引:6
Maeda Y Kimura S Kanda M Hirashima Y Hasegawa T Wakahara T Lian Y Nakahodo T Tsuchiya T Akasaka T Lu J Zhang X Gao Z Yu Y Nagase S Kazaoui S Minami N Shimizu T Tokumoto H Saito R 《Journal of the American Chemical Society》2005,127(29):10287-10290
In the applications of single-walled carbon nanotubes (SWNTs), it is extremely important to separate semiconducting and metallic SWNTs. Although several methods have been reported for the separation, only low yields have been achieved at great expense. We show a separation method involving a dispersion-centrifugation process in a tetrahydrofuran solution of amine, which makes metallic SWNTs highly concentrated to 87% in a simple way. 相似文献