全文获取类型
收费全文 | 4215篇 |
免费 | 215篇 |
国内免费 | 240篇 |
专业分类
化学 | 1229篇 |
晶体学 | 8篇 |
力学 | 612篇 |
综合类 | 22篇 |
数学 | 1861篇 |
物理学 | 938篇 |
出版年
2023年 | 96篇 |
2022年 | 62篇 |
2021年 | 78篇 |
2020年 | 123篇 |
2019年 | 90篇 |
2018年 | 79篇 |
2017年 | 142篇 |
2016年 | 155篇 |
2015年 | 120篇 |
2014年 | 245篇 |
2013年 | 362篇 |
2012年 | 210篇 |
2011年 | 259篇 |
2010年 | 221篇 |
2009年 | 330篇 |
2008年 | 333篇 |
2007年 | 309篇 |
2006年 | 222篇 |
2005年 | 186篇 |
2004年 | 158篇 |
2003年 | 141篇 |
2002年 | 116篇 |
2001年 | 87篇 |
2000年 | 90篇 |
1999年 | 67篇 |
1998年 | 52篇 |
1997年 | 45篇 |
1996年 | 32篇 |
1995年 | 33篇 |
1994年 | 37篇 |
1993年 | 21篇 |
1992年 | 29篇 |
1991年 | 17篇 |
1990年 | 7篇 |
1989年 | 14篇 |
1988年 | 20篇 |
1987年 | 8篇 |
1986年 | 11篇 |
1985年 | 16篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 9篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有4670条查询结果,搜索用时 171 毫秒
1.
2.
Liquid-liquid-solid systems are becoming increasingly common in everyday life with many possible applications. Here, we focus on a special case of such liquid-liquid-solid systems, namely, capillary suspensions. These capillary suspensions originate from particles that form a network based on capillary forces and are typically composed of solids in a bulk liquid with an added secondary liquid. The structure of particle networks based on capillary bridges possesses unique properties compared with networks formed via other attractive interactions where these differences are inherently related to the properties of the capillary bridges, such as bridge breaking and coalescence between adjacent bridges. Thus, to tailor the mechanical properties of capillary suspensions to specific requirements, it is important to understand the influences on different length scales ranging from the dynamics of the bridges with varying external stimuli to the often heterogeneous network structure. 相似文献
3.
4.
We consider the random‐cluster model (RCM) on with parameters p∈(0,1) and q ≥ 1. This is a generalization of the standard bond percolation (with edges open independently with probability p) which is biased by a factor q raised to the number of connected components. We study the well‐known Fortuin‐Kasteleyn (FK)‐dynamics on this model where the update at an edge depends on the global geometry of the system unlike the Glauber heat‐bath dynamics for spin systems, and prove that for all small enough p (depending on the dimension) and any q>1, the FK‐dynamics exhibits the cutoff phenomenon at with a window size , where λ∞ is the large n limit of the spectral gap of the process. Our proof extends the information percolation framework of Lubetzky and Sly to the RCM and also relies on the arguments of Blanca and Sinclair who proved a sharp mixing time bound for the planar version. A key aspect of our proof is the analysis of the effect of a sequence of dependent (across time) Bernoulli percolations extracted from the graphical construction of the dynamics, on how information propagates. 相似文献
5.
《中国化学快报》2020,31(7):1919-1922
A novel BODIPY (boradiazaindacene) dye denoted as BODIPY-DT containing terpyridine unit has been designed and characterized. The dye is found to be selective and visual solvatochromic sensor toward DMF among test organic solvents. The sensing process displays time-controllable, dynamic signal outputs in the emission colors including red, purple, yellow and even white emission colors. It is presented that selective free radical oxidation reaction happens during the recognition process. 相似文献
6.
Greg Orosi 《商业与工业应用随机模型》2015,31(4):515-527
In this work, we suggest a novel quadratic programming‐based algorithm to generate an arbitrage‐free call option surface. The empirical performance of the proposed method is evaluated using S&P 500 Index call options. Our results indicate that the proposed method provides a more precise fit to observed option prices than other alternative methodologies. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
7.
In this study, we investigate two important questions related to dynamic pricing in distribution channels: (i) Are coordinated pricing decisions efficient in a context where prices have carry-over effects on demand? (ii) Should firms practice a skimming or a penetration strategy if they choose to coordinate or to decentralize their activities? To answer these questions, we consider a differential game that takes place in a bilateral monopoly where the past retail prices paid by consumers contribute to the building of a reference price. The latter is used by consumers as a benchmark to evaluate the value of the product, and by firms to decide whether to adopt a skimming or a penetration strategy. 相似文献
8.
Bin Yang Chen-Wu Liang Fei-Xue Lu Qin-Ting Chen Jin Chen 《Journal of Macromolecular Science: Physics》2019,58(2):341-354
The effects of bamboo flour (BF) content on the dynamic rheological properties of BF-filled HDPE composites were investigated. Our findings showed that the addition of BF caused an enhancement of the non-Newtonianism of wood-plastic composites (WPCs) melt as well as the appearance of some new relaxation processes. In addition, the viscosity and modulus of the BF-filled HDPE composites showed a remarkable increase at 170?°C and 190?°C when the BF content exceeded 30%, which could be associated with the solid-like property of the WPCs at high BF loading, we propose. The present study we suggest will be useful to the formula design as well as the optimization of processing parameters for WPCs in general. 相似文献
9.
The tidal energy industry is progressing rapidly, but there are still barriers to overcome to realise the commercial potential of this sector. Large magnitude and highly variable loads caused by waves acting on the turbine are of particular concern. Composite blades with in-built bend-twist elastic response may reduce these peak loads, by passively feathering with increasing thrust. This could decrease capital costs by lowering the design loads, and improve robustness through the mitigation of pitch mechanisms. In this study, the previous research is extended to examine the performance of bend-twist blades in combined wave–current flow, which will frequently be encountered in the field. A scaled 3 bladed turbine was tested in the flume at IFREMER with bend-twist composite blades and equivalent rigid blades, sequentially under current and co-directional wave–current cases. In agreement with previous research, when the turbine was operating in current alone at higher tip speed ratios the bend-twist blades reduced the mean thrust and power compared to the rigid blades. Under the specific wave–current condition tested the average loads were similar on both blade sets. Nevertheless, the bend-twist blades substantially reduced the magnitudes of the average thrust and torque fluctuations per wave cycle, by up to 10% and 14% respectively. 相似文献
10.