全文获取类型
收费全文 | 1520篇 |
免费 | 157篇 |
国内免费 | 287篇 |
专业分类
化学 | 1197篇 |
晶体学 | 13篇 |
力学 | 18篇 |
综合类 | 14篇 |
数学 | 42篇 |
物理学 | 680篇 |
出版年
2024年 | 2篇 |
2023年 | 14篇 |
2022年 | 34篇 |
2021年 | 42篇 |
2020年 | 60篇 |
2019年 | 35篇 |
2018年 | 31篇 |
2017年 | 55篇 |
2016年 | 63篇 |
2015年 | 47篇 |
2014年 | 79篇 |
2013年 | 126篇 |
2012年 | 104篇 |
2011年 | 130篇 |
2010年 | 83篇 |
2009年 | 108篇 |
2008年 | 108篇 |
2007年 | 121篇 |
2006年 | 98篇 |
2005年 | 71篇 |
2004年 | 55篇 |
2003年 | 67篇 |
2002年 | 46篇 |
2001年 | 31篇 |
2000年 | 48篇 |
1999年 | 41篇 |
1998年 | 38篇 |
1997年 | 45篇 |
1996年 | 29篇 |
1995年 | 19篇 |
1994年 | 25篇 |
1993年 | 34篇 |
1992年 | 25篇 |
1991年 | 13篇 |
1990年 | 4篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 6篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1964条查询结果,搜索用时 15 毫秒
1.
Paramagnetic pyrroline and 1,2,3,6-tetrahydropyridine derivatives of BODIPY and their diamagnetic analogs have been synthesized and characterized as novel redox double sensor and cation sensitive reagents. 相似文献
2.
The association of complex formation with static quenching in CT systems was investigated. Evaluation of the data made evident
that the inner filter effect must be allowed for. Time-resolved and temperature-dependent stationary measurements of fluorescence
led to the separation of dynamic and static quenching components. The static quenching constant is discussed with respect
to the equilibrium constant of complex formation determined by absorption spectroscopy. 相似文献
3.
Modified Stern-Volmer equation is obeyed by bovine serum albumin (BSA)-iodide system showing selective quenching of tryptophanyl
fluorescence of BSA. The fraction of accessible protein fluorescence is 0.56 and the effective Stern-Volmer constant is 290
M-1 at pH 7.4 in 0.005 M phosphate buffer at 25°C. Collisional quenching is operative both in the BSA -I−1 system and the model system, tryptophan-I−1. It is supported by the observed relationship between the ratio of quenching rate constants (k
q
) and diffusion coefficients and alsok
q
with bulk viscosity. 相似文献
4.
Applied Biochemistry and Biotechnology - 相似文献
5.
We have studied the characteristic features of carbazole phosphorescence quenching by benzophenone in toluene at 77 K. We
have shown that the decrease in the relative phosphorescence intensity for carbazole (energy donor) by a greater factor than
we see for the relative change in its decay time is due to the fact that a change in the phosphorescence decay time occurs
only for carbazole molecules participating in triplet-triplet energy transfer, while the substantial decrease in the phosphorescence
intensity for carbazole with no change in the phosphorescence decay time is connected with quenching of its singlet states.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 554–556, July–August, 2006. 相似文献
6.
meso-四(4-乙酰氧基苯)卟啉-铜(Ⅱ)-乳化剂OP体系荧光熄灭法测定微量铜(Ⅱ)的研究 总被引:1,自引:0,他引:1
本文研究了高灵敏的meso-四(4-乙酰氧基苯)卟啉[T(4-AOP)P]-铜(Ⅱ-乳化剂OP体系。在酸度为pH5.0~5.6范围内形成的三元络合物可引起T(4-AOP)P-OP荧光强度的定量熄灭,其Ex=413nm,EM=656.9nm,Cu(Ⅱ)浓度在0~0.150μg/ml范围内有良好的线性关系,回归方程F=25.51-8.45m,试验了14种离子的干扰影响,并用此法测定了小球藻中Cu的含量,回收率达96~104%。 相似文献
7.
Taking both the heterogeneous catalytic processes, including the surface formation of particles with excited internal degrees of freedom, and the processes of multicomponent diffusion and heat transfer in the MESOX apparatus fully into account makes it possible to obtain a recombination coefficient and an accommodation coefficient of the oxygen-atoms-on-quartz recombination energy which are in good agreement with the experimental data. The heterogeneous catalysis model constructed can be used effectively for predicting the heat fluxes to the surface of reentry vehicles on their entry into the Earth’s atmosphere. 相似文献
8.
本文研究了在PVA和Tween 80存在下,铋离子与硫氰酸钾和丁基罗丹明B形成缔合型三元配合物,使丁基罗丹明B的荧光熄灭,建立了痕量铋的荧光分析新方法。工作曲线线性范围为0~5.0μg/25mL。方法灵敏度高,ε_(588)为3.5×10~5L·mol~(-1)·cm~(-1),操作简便。用于铸铁中痕量铋的测定,结果满意。 相似文献
9.
10.
The constants of binding dye molecules with the micelles of sodium dodecyl sulfate are determined using quenching of delayed fluorescence of acridine dyes by sodium iodide in aqueous–micellar solutions. Kinetic equations have been composed that describe the processes of deactivation of the excited states of dyes. By solving these equations at the concentration of the quencher sodium iodide corresponding to the minimum lifetime of triplet states and at the concentration of micelles corresponding to the least value of the delayed fluorescence quenching rate constants, we obtained the constants of binding dyes with micelles equal to 1.3·107, 2.9·107, and 3.1·107 M–1 for trypaflavine, acridine orange, and acridine yellow, respectively. We calculated the rate constants of quenching of the triplet states of the molecules of dyes by iodide ions (I
–) that decreased in transition from trypaflavine to acridine orange and acridine yellow. 相似文献