全文获取类型
收费全文 | 993篇 |
免费 | 8篇 |
国内免费 | 2篇 |
专业分类
化学 | 346篇 |
力学 | 48篇 |
数学 | 376篇 |
物理学 | 233篇 |
出版年
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 10篇 |
2013年 | 19篇 |
2012年 | 42篇 |
2011年 | 55篇 |
2010年 | 23篇 |
2009年 | 15篇 |
2008年 | 27篇 |
2007年 | 37篇 |
2006年 | 27篇 |
2005年 | 43篇 |
2004年 | 24篇 |
2003年 | 27篇 |
2002年 | 24篇 |
2001年 | 16篇 |
2000年 | 27篇 |
1999年 | 18篇 |
1998年 | 16篇 |
1997年 | 20篇 |
1996年 | 26篇 |
1995年 | 29篇 |
1994年 | 28篇 |
1993年 | 37篇 |
1992年 | 40篇 |
1991年 | 37篇 |
1990年 | 41篇 |
1989年 | 17篇 |
1988年 | 20篇 |
1987年 | 12篇 |
1986年 | 19篇 |
1985年 | 11篇 |
1984年 | 26篇 |
1983年 | 7篇 |
1982年 | 15篇 |
1981年 | 16篇 |
1980年 | 7篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 13篇 |
1976年 | 14篇 |
1975年 | 8篇 |
1974年 | 9篇 |
1973年 | 4篇 |
1972年 | 6篇 |
1968年 | 8篇 |
1938年 | 5篇 |
排序方式: 共有1003条查询结果,搜索用时 15 毫秒
1.
Patterson JR Barker A Briere RA Gibbons LK Makoff G Papadimitriou V Somalwar S Wah YW Winstein B Winston R Woods M Yamamoto H Swallow E Bock GJ Coleman R Enagonio J Hsiung YB Stanfield K Stefanski R Yamanaka T Blair G Gollin GD Karlsson M Okamitsu JK Tschirhart R Brisson JC Debu P Peyaud B Turlay R Vallage B 《Physical review letters》1990,64(13):1491-1494
2.
3.
4.
Patterson P 《OR manager》1990,6(4):1, 8-1, 9
5.
6.
7.
8.
M S Patterson S J Madsen B C Wilson 《Journal of photochemistry and photobiology. B, Biology》1990,5(1):69-84
Singlet oxygen (1O2) is thought to be the cytotoxic agent in photodynamic therapy (PDT) with current photosensitizers. Direct monitoring of 1O2 concentration in vivo would be a valuable tool in studying biological response. Attempts were made to measure 1O2 IR luminescence during PDT of cell suspensions and two murine tumour models using the photosensitizers Photofrin II and aluminium chlorosulphonated phthalocyanine. Instrumentation was virtually identical to that devised by Parker in the one positive report of in vivo luminescence detection in the literature. Despite the fact that our treatments caused cell killing and tissue necrosis, we were unable to observe 1O2 emission under any conditions. We attribute this negative result to a reduction in 1O2 lifetime in the cellular environment. Quantitative calibration of our system allowed us to estimate that the singlet oxygen lifetime in tissue is less than 0.5 microsecond. Some technical improvements are suggested which would improve detector performance and perhaps make such measurements feasible. 相似文献
9.
Using the Picker flow microcalorimeter, excess heat capacities have been obtained at 25°C throughout the concentration range for 2,2-dimethylbutane,n-hexane, and cyclohexane each mixed with a series of hexadecane isomers of increasing degrees of orientational order, as determined by depolarized Rayleigh scattering. The isomers are 2,2,4,4,6,8,8-heptamethylnonane, 6-, 4-, and 2-methylpentadecane, andn-hexadecane. Thec
p
E
values are negative, increasing rapidly in magnitude with increase of orientational order, and are not predicted by the Prigogine—Flory theory which neglects order. Values ofc
p
E
are obtained at 10, 25, and 55°C for cyclohexane +6-, 4-, and 2-methylpentadecane which with other literature data lead to the temperature dependence of the thermodynamic excess functions for cyclohexane solutions of the five C16 isomers. The excess enthalpy and entropy vary with the C16 isomer and with temperature, but the corresponding variation of the excess free energy is small, indicating a high degree of enthalpy-entropy compensation. This is consistent with a rapid decrease with temperature of orientational order in the C16 isomers. 相似文献
10.
Patterson P 《OR manager》1995,11(3):1, 6-1, 8