全文获取类型
收费全文 | 3493篇 |
免费 | 406篇 |
国内免费 | 224篇 |
专业分类
化学 | 2425篇 |
晶体学 | 45篇 |
力学 | 126篇 |
综合类 | 8篇 |
数学 | 480篇 |
物理学 | 1039篇 |
出版年
2024年 | 3篇 |
2023年 | 42篇 |
2022年 | 68篇 |
2021年 | 96篇 |
2020年 | 128篇 |
2019年 | 117篇 |
2018年 | 102篇 |
2017年 | 89篇 |
2016年 | 142篇 |
2015年 | 156篇 |
2014年 | 149篇 |
2013年 | 273篇 |
2012年 | 311篇 |
2011年 | 317篇 |
2010年 | 194篇 |
2009年 | 174篇 |
2008年 | 233篇 |
2007年 | 226篇 |
2006年 | 186篇 |
2005年 | 157篇 |
2004年 | 106篇 |
2003年 | 120篇 |
2002年 | 84篇 |
2001年 | 86篇 |
2000年 | 70篇 |
1999年 | 54篇 |
1998年 | 51篇 |
1997年 | 36篇 |
1996年 | 51篇 |
1995年 | 32篇 |
1994年 | 36篇 |
1993年 | 37篇 |
1992年 | 26篇 |
1991年 | 28篇 |
1990年 | 14篇 |
1989年 | 28篇 |
1988年 | 15篇 |
1987年 | 9篇 |
1986年 | 21篇 |
1985年 | 12篇 |
1984年 | 12篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1975年 | 3篇 |
1973年 | 4篇 |
1936年 | 1篇 |
排序方式: 共有4123条查询结果,搜索用时 15 毫秒
951.
Kedian Mu Weiru LiuZhi Jin David Bell 《International Journal of Approximate Reasoning》2011,52(7):978-999
Measuring the degree of inconsistency of a belief base is an important issue in many real-world applications. It has been increasingly recognized that deriving syntax sensitive inconsistency measures for a belief base from its minimal inconsistent subsets is a natural way forward. Most of the current proposals along this line do not take the impact of the size of each minimal inconsistent subset into account. However, as illustrated by the well-known Lottery Paradox, as the size of a minimal inconsistent subset increases, the degree of its inconsistency decreases. Another lack in current studies in this area is about the role of free formulas of a belief base in measuring the degree of inconsistency. This has not yet been characterized well. Adding free formulas to a belief base can enlarge the set of consistent subsets of that base. However, consistent subsets of a belief base also have an impact on the syntax sensitive normalized measures of the degree of inconsistency, the reason for this is that each consistent subset can be considered as a distinctive plausible perspective reflected by that belief base, whilst each minimal inconsistent subset projects a distinctive view of the inconsistency. To address these two issues, we propose a normalized framework for measuring the degree of inconsistency of a belief base which unifies the impact of both consistent subsets and minimal inconsistent subsets. We also show that this normalized framework satisfies all the properties deemed necessary by common consent to characterize an intuitively satisfactory measure of the degree of inconsistency for belief bases. Finally, we use a simple but explanatory example in requirements engineering to illustrate the application of the normalized framework. 相似文献
952.
Jianhai Mu Ganzuo Li∗ Zhengwu Wang Liqiang Zheng 《Journal of Dispersion Science and Technology》2013,34(7):999-1005
The changes of cloud points and surface tensions of a nonionic surfactant dodecyl polyoxycthylene(5) polyoxypropylene(4) ether (LS54) in aqueous solutions with added polyvinylpyrrolide (PVP-K90) were determined in order to evaluate polymer-surfactant interactions in the bulk solutions. A new model, corona-shaped intra-chain micelles, was applied lo these phenomena and the thermodynamic parameters of micellization were determined. 相似文献
953.
954.
955.
956.
Zhaoliang Cao Quanquan Mu Guillaume Dovillaire Thomas Grandin Emeric Lavergne Lifa Hu Li Xuan 《Liquid crystals》2007,34(10):1227-1232
The effect of twisted alignment on the phase modulation of a liquid crystal wave-front corrector was investigated. First, the effect of twisted alignment is discussed in terms of the modulation principle of the liquid crystal molecule. Only partial incident light can be modulated because of the effect of the twisted alignment. Other unmodulated light will affect the correction accuracy and the resolution of the image. The blazed grating method is proposed to solve this problem. Adaptive correction was performed without the blazed grating method and the correction results are poor. A similar adaptive correction experiment was performed with the blazed grating method and a better correction result is obtained. The residual averaged wave-front errors are PV = 0.101λ and RMS = 0.015λ and a resolvable image is obtained. 相似文献
957.
F. García-Molina J. L. Muñoz P. A. García-Ruíz J. N. Rodríguez-López F. García-Cánovas J. Tudela R. Varón 《Journal of mathematical chemistry》2007,41(4):393-406
Tyrosinase is a cuproprotein that hydroxylates monophenols to o-diphenols, which it then oxidises to o-quinones, using molecular oxygen. Based on kinetic studies of the steady state and measuring product formation during the
action of the enzyme on o-diphenols, we determine the Michaelis constant and the maximum velocity, respectively. Similarly, we determine these kinetic
constants for the enzyme acting on monophenols. From these constants obtained for a monophenol/o-diphenol pair, it is possible to calculate a new constant, the Michaelis constant of the enzyme for an o-diphenol acting on the corresponding monophenol, by means of an equation that relates the above-mentioned kinetic constants.
Furthermore, it is also possible to establish the relation between the Michaelis constants for the oxygen in the presence
of monophenol and in the presence of o-diphenol from the relation between the maximum velocities of the monophenol and o-diphenol experimentally determined by measuring aminochrome. From applying the equations described above to the kinetic data
of the many tyrosinases described in the literature, we find that the Michaelis constant for the o-diphenol in the presence of monophenol is much lower than that obtained when the enzyme acts on o-diphenol alone. The Michaelis constant for oxygen in the presence of monophenol is also much lower than that obtained in
the presence of its o-diphenol. 相似文献
958.
959.
960.