全文获取类型
收费全文 | 1190篇 |
免费 | 25篇 |
国内免费 | 5篇 |
专业分类
化学 | 869篇 |
晶体学 | 15篇 |
力学 | 18篇 |
数学 | 87篇 |
物理学 | 231篇 |
出版年
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 19篇 |
2020年 | 14篇 |
2019年 | 14篇 |
2018年 | 13篇 |
2017年 | 8篇 |
2016年 | 22篇 |
2015年 | 19篇 |
2014年 | 25篇 |
2013年 | 45篇 |
2012年 | 65篇 |
2011年 | 74篇 |
2010年 | 49篇 |
2009年 | 33篇 |
2008年 | 92篇 |
2007年 | 86篇 |
2006年 | 80篇 |
2005年 | 82篇 |
2004年 | 90篇 |
2003年 | 53篇 |
2002年 | 51篇 |
2001年 | 18篇 |
2000年 | 19篇 |
1999年 | 16篇 |
1998年 | 10篇 |
1997年 | 11篇 |
1996年 | 14篇 |
1995年 | 14篇 |
1994年 | 19篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 9篇 |
1980年 | 12篇 |
1979年 | 5篇 |
1978年 | 12篇 |
1977年 | 5篇 |
1976年 | 10篇 |
1974年 | 6篇 |
1972年 | 5篇 |
排序方式: 共有1220条查询结果,搜索用时 31 毫秒
1.
Hideaki Murasugi Dr. Shohei Kumagai Dr. Hiroaki Iguchi Prof. Dr. Masahiro Yamashita Dr. Shinya Takaishi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9885-9891
Crystal structures of a series of organic–inorganic hybrid gold iodide perovskites, formulated as A2[AuII2][AuIIII4] [A=methylammonium (MA) ( 1 ) and formamidinium (FA) ( 2 )], A′2[I3]1−x[AuII2]x[AuIIII4] [A′=imidazolium (IMD) ( 3 ), guanidinium (GUA) ( 4 ), dimethylammonium (DMA) ( 5 ), pyridinium (PY) ( 6 ), and piperizinium (PIP) ( 7 )], systematically changed depending on the cation size. In addition, triiodide (I3−) ions were partly incorporated into the AuI2− sites of 3 – 7 , whereas they were not incorporated into those of 1 and 2 . Such a difference comes from the size of the organic cation. Optical absorption spectra showed characteristic intervalence charge-transfer bands from AuI to AuIII species, and the optical band gap increased as the size of the cation became larger. 相似文献
2.
Sayaka Wada Kazuhiko Fujiwara Hideaki Monjushiro Hitoshi Watarai 《Analytical sciences》2004,20(11):1489-1491
The direct measurement of the circular dichroism (CD) spectra of liquid/liquid interface has been achieved for the first time by the centrifugal liquid membrane (CLM) method combined with a conventional CD spectropolarimetry. In the sample chamber of the CD spectropolarimeter, a cylindrical glass cell containing small amounts of organic and aqueous phases was rotated at ca. 7000 rpm to generate a two-phase liquid membrane with a high specific interfacial area. The CD spectra of the J-aggregate of protonated 5,10,15,20-tetraphenylporphyrin formed at the toluene/sulfuric acid interface in the rotating cell have been measured. The results demonstrated the novelty and advantages of this method. 相似文献
3.
Takashi Yoshitake Ryuji Iizuka Kaoru Fujino Osamu Inoue Kenji Yamagata Hitoshi Nohta Masatoshi Yamaguchi 《Analytical sciences》2004,20(12):1687-1690
An improved high-performance liquid-chromatographic (HPLC) assay for the simultaneous determination of serotonin (5-HT) and 5-hydroxyindole-3-acetic acid (5-HIAA) in human urine is reported. Following the automated precolumn derivatization of urinary 5-HT and 5-HIAA with benzylamine, the derivatives are separated by isocratic elution on a reversed-phase C18 semi-microbore column, and are fluorometrically detected at an excitation wavelength of 345 nm and an emission wavelength of 480 nm. The detection limits of 5-HT and 5-HIAA are 7 and 5 nmol/l in urine (0.7 and 0.5 fmol/20-microl injection). The proposed automatic method permits a highly selective and sensitive determination of 5-HT and 5-HIAA in human urine without any sample purification. 相似文献
4.
5.
6.
10Gbit/s time-spread/wavelength-hop optical code generation and decoding are performed by dispersion-compensating fiber Bragg grating (FBG) en/decoder pair. Error-free 10km single mode fiber (SMF) transmission of 10Gbit/s optical code division multiplexing (OCDM) has been experimentally demonstrated. 相似文献
7.
A composition spread metal thin film fabrication technique based on ion beam sputter deposition method was developed. The technique enables us to fabricate any desired part or a complete binary/ternary composition spread metal thin films onto a single substrate by sequentially sputtering different target materials. Composition spread metal thin films can be deposited directly on a dielectric film in patterned electrode shape for C-V and I-V measurements. The system could be especially useful in the search for new multi-component metal gate materials. 相似文献
8.
Hideaki Ishikawa 《Archiv der Mathematik》2002,79(6):439-448
In this paper we introduce a certain sum by using Dirichlet characters. We investigate the Riesz mean of the sum using the
analytic properties of the MultipleL-function systematically.
Eine überarbeitete Fassung ging am 6. 8. 2001 ein 相似文献
9.
In proportion to the environmental pollution problems caused by organotin compounds, the genotoxicities of tin compounds in the environments have become of interest so as to estimate their safety in recent years. In this work, isolated λ-DNA (double-strand DNA) was incubated with inorganic tin(II) and tin(IV) and five organotin compounds [n-butyltin trichloride, di(n-butyltin) dichloride, methyltin trichloride, dimethyltin dichloride and trimethyltin chloride] in reaction systems both with and without hydrogen peroxide (H2O2) content. The tin compounds tested in this study did not induce DNA breakage in the absence of hydrogen peroxide. Divalent inorganic tin (SnCl2) and tetravalent inorganic tin (SnCl4) caused DNA breakage in the presence of hydrogen peroxide (10 mM), and the DNA damage activity of inorganic tin was much more potent in divalent inorganic tin (SnCl2) than in tetravalent inorganic tin (SnCl4). Divalent inorganic tin (SnCl2) induced DNA breakage in a concentration-dependent fashion at concentrations greater than 0.1 mM of SnCl2 in the presence of hydrogen peroxide (10 mM). DNA breakage was not caused by n-butyltin compounds and methyltin compounds either in the presence or in the absence of hydrogen peroxide. 相似文献
10.
Kuniaki Tatsuta Yoshiya Amemiya Yoshinobu Kanemura Hideaki Takahashi Mitsuhiro Kinoshita 《Tetrahedron letters》1982,23(33):3375-3378
Tylosin has been synthesized byregio- and stereoselective introduction of the amino disaccharide moiety and D-mycinose onto the previously synthesized 16-membered-ring aglycone. 相似文献