全文获取类型
收费全文 | 107篇 |
免费 | 2篇 |
国内免费 | 2篇 |
专业分类
化学 | 71篇 |
晶体学 | 1篇 |
数学 | 24篇 |
物理学 | 15篇 |
出版年
2022年 | 1篇 |
2021年 | 3篇 |
2019年 | 2篇 |
2014年 | 4篇 |
2013年 | 5篇 |
2012年 | 8篇 |
2011年 | 8篇 |
2010年 | 10篇 |
2009年 | 3篇 |
2008年 | 12篇 |
2007年 | 7篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 4篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1992年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有111条查询结果,搜索用时 15 毫秒
21.
Kazufumi Toume Kentaro Yamaguchi Thaworn Kowithayakorn Kanki Komiyama 《Tetrahedron》2004,60(48):10817-10824
Five novel natural products classified as dimeric sesquiterpenes, named parviflorenes B-F (2-6), possessing three types of novel backbone frameworks, have been isolated from Curcuma parviflora (Zingiberaceae). The structures of 2-6 were elucidated by means of spectroscopic studies, and the structure of 2 was further unambiguously established by X-ray crystallographic analysis. Compounds 2, 4, and 6 have an unsymmetrical bis-cadinane skeleton, while compound 3 is a dimer of cadinane and iso-cadinane, and compound 5 possesses another novel carbon framework consisting of two cadinanes with different bond-connection. These new compounds with novel carbon skeletons showed cytotoxicity against tumor cell lines. 相似文献
22.
Shuntaro Mataka Masayoshi Kurisu Kazufumi Takahashi And Masashi Tashiro 《Journal of heterocyclic chemistry》1984,21(4):1157-1160
Bromomethyl-1,2,5-thiadiazoles 2a-c were prepared by bromination of methyl-1,2,5-thiadiazoles 1a-c by NBS in refluxing carbon tetrachloride. When bromination of 1a and 1b was carried out under irradiation of tungusten lamp, mixtures of cis -5a and b and trans-1,2-dibromo-1,2-bis(1,2,5-thiadiazol-3-yl)ethylene ( 6a and b ) were obtained. 相似文献
23.
Kimura M Futamata M Shibata K Tamaru Y 《Chemical communications (Cambridge, England)》2003,(2):234-235
A combination of catalytic amounts of Pd (0.05 mmol) and Et3B (0.3 mmol) promotes allylic alkylation of primary and secondary aromatic and aliphatic amines (1.0 mmol) by the direct use of allylic alcohols, providing tertiary amines in excellent yields under mild conditions (room temperature approximately 50 degrees C). 相似文献
24.
25.
Takashi Katsu Tomonori Imamura Keiko Komagoe Kazufumi Masuda Tohru Mizushima 《Analytical sciences》2007,23(5):517-522
The changes induced by biologically active substances in the permeability to K+ and calcein of liposomes composed of egg phosphatidylcholine and cholesterol were measured simultaneously in order to rapidly screen the sizes of pores formed in a membrane, using different sized markers. The substances examined in the present study were classified into three types based on differences in the rates at which K+ and calcein were released. The first type released only K+, and included gramicidin A. The second type predominantly released K+, preceding the release of calcein, and included amphotericin B and nystatin. The third type, including antimicrobial peptides, such as gramicidin S, alamethicin, and melittin, and several membrane-active drugs, like celecoxib (non-steroidal anti-inflammatory drug), 1-dodecylazacycloheptan-2-one (named azone; skin permeation enhancer), and chlorpromazine (tranquilizer), caused the release of K+ and calcein simultaneously. Thus, the sizes of pores formed in a liposomal membrane increased in the following order: types one, two, and three. We determined the size more precisely by conducting an osmotic protection experiment, measuring the release of calcein in the presence of osmotic protectants of different sizes. The radii of pores formed by the second type, amphotericin B and nystatin, were 0.36 - 0.46 nm, while the radii of pores formed by the third type were much larger, 0.63 - 0.67 nm or more. The permeability changes induced by substances of the third type are discussed in connection with a transient pore formed in a lipid packing mismatch taking place during the phase transition of dipalmitoylphosphatidylcholine liposomes. 相似文献
26.
Masafumi Kashii Yoichiroh Hosokawa Hiroshi Kitano Yusuke Mori Kazufumi Takano Hiroyoshi Matsumura Tsuyoshi Inoue Satoshi Murakami Kazuomi Sugamoto Takatomo Sasaki Hiroshi Masuhara 《Applied Surface Science》2007,253(15):6447-6450
For precise X-ray diffraction (XRD) measurement giving the three-dimensional structure of proteins, it is important to prepare high-quality single crystals with suitable shape. As a new processing technique to obtain such protein crystals, we employed femtosecond laser-induced cleaving of protein crystal in a growth vessel containing water solution. An intact protein crystal was precisely processed without mechanical contact in its sealed growth vessel by focusing femtosecond laser pulses. We confirmed that three-dimensional processing of the crystal in its supersaturated solution was realized using multiphoton absorption and that the processing was efficiently enhanced by the cleaving behavior attributed to a photomechanical mechanism of the femtosecond laser ablation. 相似文献
27.
28.
Mihoko Maruyama Noriko Shimizu Shigeru Sugiyama Yoshinori Takahashi Hiroaki Adachi Kazufumi Takano Satoshi Murakami Tsuyoshi Inoue Hiroyoshi Matsumura Yusuke Mori 《Journal of Crystal Growth》2010,312(19):2771-2774
Silicone glue (modified silicone polymer) is widely used for both experiments involving inorganic crystal growth and those involving organic materials like proteins. This material is very useful for building a hand-made experiment setup or for fixing protein crystals to specific locations. Though silicone glue is regarded as harmful to proteins, no systematic verification was performed to investigate its impurity effects on protein crystal growth. We focused on and estimated the impurity effects of silicone glue on protein crystal growth. 相似文献
29.
Tsuyoshi Sawada Mizue Kuroki Tomoya Ogawa Kentaro Shimojo Kazufumi Chifuku Hirotaka Ihara 《Tetrahedron letters》2010,51(31):4033-4036
In this study, 9,10-diacetoxyl-2,7-di-tert-butyl-trans-10b,10c-dimethyl-10b,10c-dihydropyrene annelated with a dihydrothieno[3.4-b]pyrazine unit (1a) was prepared, for the first time, from 5,13-di-tert-butyl-8,16-dimethyl-1,2,9,10-tetrahydroxy[2.2]metacyclophane and 3,4-diaminothiophene in two steps. The photoisomerization property of 1 was investigated by UV and 1H NMR spectroscopies, and the quantitative isomerization between the more stable dihydropyrene (DHP) form and the less stable metacyclophane-diene (MCPD) form was observed. A thermally induced return reaction from the MCPD to the DHP form was examined at various temperatures, and the reaction rate was 0.0049 min−1 at 45 °C, which is slower than that of the parent MCPD. 相似文献
30.
Sakai K Koga T Imai Y Maehara S Xu CN 《Physical chemistry chemical physics : PCCP》2006,8(24):2819-2822
We have invented a new device based on atomic force microscopy that measures the emission from a single microparticle by force direct application using the AFM probe, and successfully observed emission in the region of the elastic deformation, friction, and destructive deformation. 相似文献