全文获取类型
收费全文 | 311篇 |
免费 | 2篇 |
专业分类
化学 | 205篇 |
晶体学 | 3篇 |
数学 | 25篇 |
物理学 | 80篇 |
出版年
2020年 | 3篇 |
2014年 | 2篇 |
2013年 | 10篇 |
2012年 | 11篇 |
2011年 | 12篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 3篇 |
2006年 | 6篇 |
2005年 | 9篇 |
2004年 | 2篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 7篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1992年 | 9篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1986年 | 12篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1978年 | 11篇 |
1977年 | 4篇 |
1976年 | 10篇 |
1975年 | 2篇 |
1974年 | 6篇 |
1973年 | 13篇 |
1971年 | 5篇 |
1970年 | 7篇 |
1969年 | 6篇 |
1968年 | 9篇 |
1967年 | 3篇 |
1966年 | 2篇 |
1964年 | 2篇 |
1917年 | 2篇 |
1910年 | 2篇 |
1904年 | 2篇 |
排序方式: 共有313条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
U. Steiner M. Hafner S. Schreiner H. E. A. Kramer 《Photochemistry and photobiology》1974,19(2):119-128
Abstract— While studying the photoreduction of some dyes (D) by reducing agents (R), it was observed that the quantum yield of the photoreduction increases considerably upon addition of a third substance (C), whereas it is very small when the dye is photoreduced by C alone (catalytic effect), (see Table 1).
The system thionine (D), allylthiourea (R), and azulene (C) was investigated in detail using both flash photolysis and continuous illumination. On photolysis, thionine is converted into its photo-reduced form, leucothionine. Azulene reacts with the basic form of the thionine triplet3 TH + to produce the semithionine radical. In the system thionine and azulene, most of these radicals revert back to thionine. When ATU (˜ 102- M ) is added to thionine and azulene (3 × 10-4 M ), the semithionine radicals are reduced to leucothionine; the quantum yield of this reduction is considerably higher than in the system thionine and allylthiourea. Flash experiments demonstrate that allylthiourea does not react with the semithionine radicals.
At very high ATU concentrations (≥ 10-1 M ), however, the primary reaction is between thionine triplet and allylthiourea; under these conditions the quantum yield is not influenced by azulene (3 × 10-4 M ). 相似文献
The system thionine (D), allylthiourea (R), and azulene (C) was investigated in detail using both flash photolysis and continuous illumination. On photolysis, thionine is converted into its photo-reduced form, leucothionine. Azulene reacts with the basic form of the thionine triplet
At very high ATU concentrations (≥ 10
6.
7.
Wijkens P Jastrzebski JT van Der Schaaf PA Kolly R Hafner A van Koten G 《Organic letters》2000,2(11):1621-1624
A general method for the functionalization of Si-Cl terminated carbosilane dendritic molecules via organolithium or organomagnesium reagents is described. Quantitative exchange of the bromine atoms of 4-bromophenyl-functionalized dendrimers affords polylithiated species that are valuable starting materials for further functionalization, e.g., into pyridyl alcohols. The latter were successfully applied as catalyst precursors in a ruthenium-mediated ring-closure metathesis reaction. 相似文献
8.
Uwe K. A. Klein Gertrud Hönes Friedrich W. Hafner 《Photochemistry and photobiology》1984,40(5):569-574
Abstract —The time-dependent rotational relaxation of Rhodamine 6G in fresh and dried human blood serum was investigated using picosecond phasefluorometry. Measurements were also carried out in aqueous solutions of amino acids, glucose, urea, and bovine serum albumin to evaluate our model for the interactions. It is shown that the distribution of Rhodamine 6G between the aqueous and the protein phase of the blood serum strongly depends on protein concentration and temperature. 相似文献
9.
10.