全文获取类型
收费全文 | 3273篇 |
免费 | 100篇 |
国内免费 | 9篇 |
专业分类
化学 | 2453篇 |
晶体学 | 25篇 |
力学 | 88篇 |
数学 | 318篇 |
物理学 | 498篇 |
出版年
2023年 | 25篇 |
2022年 | 37篇 |
2021年 | 67篇 |
2020年 | 55篇 |
2019年 | 68篇 |
2018年 | 49篇 |
2017年 | 32篇 |
2016年 | 104篇 |
2015年 | 74篇 |
2014年 | 84篇 |
2013年 | 152篇 |
2012年 | 193篇 |
2011年 | 241篇 |
2010年 | 128篇 |
2009年 | 101篇 |
2008年 | 176篇 |
2007年 | 157篇 |
2006年 | 180篇 |
2005年 | 164篇 |
2004年 | 108篇 |
2003年 | 109篇 |
2002年 | 81篇 |
2001年 | 50篇 |
2000年 | 43篇 |
1999年 | 26篇 |
1998年 | 29篇 |
1997年 | 15篇 |
1996年 | 37篇 |
1995年 | 39篇 |
1994年 | 33篇 |
1993年 | 40篇 |
1992年 | 27篇 |
1991年 | 30篇 |
1990年 | 28篇 |
1989年 | 24篇 |
1988年 | 20篇 |
1987年 | 22篇 |
1986年 | 17篇 |
1985年 | 33篇 |
1984年 | 26篇 |
1983年 | 23篇 |
1982年 | 28篇 |
1981年 | 17篇 |
1980年 | 19篇 |
1978年 | 20篇 |
1977年 | 22篇 |
1967年 | 17篇 |
1966年 | 20篇 |
1965年 | 39篇 |
1964年 | 45篇 |
排序方式: 共有3382条查询结果,搜索用时 18 毫秒
1.
A new parallel storm surge model, the Parallel Environmental Model (PEM), is developed and tested by comparisons with analytic solutions. The PEM is a 2‐D vertically averaged, wetting and drying numerical model and can be operated in explicit, semi‐implicit and fully implicit modes. In the implicit mode, the propagation, Coriolis and bottom friction terms can all be treated implicitly. The advection and diffusion terms are solved with a parallel Eulerian–Lagrangian scheme developed for this study. The model is developed specifically for use on parallel computer systems and will function accordingly in either explicit of implicit modes. Storm boundary conditions are based on a simple exponential decay of pressure from the centre of a storm. The simulated flooding caused by a major Category 5 hurricane making landfall in the Indian River Lagoon, Florida is then presented as an example application of the PEM. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
2.
This contribution discusses the phenomena of retrograde condensation of one or two liquids. It w1 be shown that both phenomena can be well understood. Also the relation of retrograde condensation of one liquid phase with the condensation behavior of natural gas will be discussed. Similarly that of two liquid phases with multiple phase behavior occurring in low temperature reservoir fluids will be pointed out. 相似文献
3.
Kevin S. Peters 《Angewandte Chemie (International ed. in English)》1994,33(3):294-302
Why have molecules only been seen but not heard? For over a century chemists have probed reactions with various spectroscopic methods to learn about structures, dynamics, and reactivities of their molecules. What they have not done is to listen to their molecules react. Although the photoacoustic phenomenon has been known since 1880, it is only in the last twenty years that technology has developed to the point where sound waves produced by reacting molecules can be time resolved and the information contained within the waves deciphered. The information content within the photoacoustic wave is indeed rich, for one can learn about the dynamics and the magnitude of enthalpy changes associated with the reaction as well as the changes in molecular volume. This review article chronicles the development of time-resolved photoacoustic calorimetry and its application to a variety of reactions encountered in organic and organometallic chemistry and biochemistry. 相似文献
4.
5.
6.
Hans Peters Hans van der Stel Ton Storcken 《Mathematical Methods of Operations Research》1993,38(2):213-229
A voting scheme assigns to each profile of alternatives reported byn individuals a compromise alternative. A voting scheme is strategy-proof if no individual is better off by lying, i.e., not reporting a best alternative. In this paper the main results concern the case where the set of alternatives is the Euclidean plane and the preferences are Euclidean. It is shown that for strategy-proof voting schemes continuity is equivalent to convexity of the range of the voting scheme. Using a result by Kim and Roush (1984), this leads to characterizations of surjective or unanimous, anonymous, strategy-proof voting schemes.Furthermore, the paper contains an extensive discussion of related results in the area. 相似文献
7.
8.
9.
10.
Proteins obtained from agricultural sources represent a unique feedstock from which to prepare thermally processable polymers. In this study, thermally processed feather keratin films were composted with three-month-old compost inoculum in self-heating laboratory composters for 30 days and temperature and carbon dioxide development monitored. About 24% of the available carbon in the feather keratin polymer (FKP) was metabolized in this time and this may not be high enough for some applications. Degradation of the feather keratin polymers was observed within 10 days with concurrent molecular weight reduction measured using FT-IR. Visual inspection of the polymers also showed destruction of the films. A change in crystallinity was observed in DSC analysis and some degradation processes could be inferred from this as well. 相似文献