全文获取类型
收费全文 | 8076篇 |
免费 | 1032篇 |
国内免费 | 601篇 |
专业分类
化学 | 3611篇 |
晶体学 | 1310篇 |
力学 | 597篇 |
综合类 | 119篇 |
数学 | 1526篇 |
物理学 | 2546篇 |
出版年
2024年 | 6篇 |
2023年 | 77篇 |
2022年 | 181篇 |
2021年 | 212篇 |
2020年 | 217篇 |
2019年 | 183篇 |
2018年 | 152篇 |
2017年 | 216篇 |
2016年 | 321篇 |
2015年 | 250篇 |
2014年 | 391篇 |
2013年 | 573篇 |
2012年 | 420篇 |
2011年 | 560篇 |
2010年 | 563篇 |
2009年 | 512篇 |
2008年 | 544篇 |
2007年 | 572篇 |
2006年 | 529篇 |
2005年 | 433篇 |
2004年 | 416篇 |
2003年 | 329篇 |
2002年 | 251篇 |
2001年 | 216篇 |
2000年 | 230篇 |
1999年 | 174篇 |
1998年 | 160篇 |
1997年 | 168篇 |
1996年 | 111篇 |
1995年 | 92篇 |
1994年 | 95篇 |
1993年 | 64篇 |
1992年 | 78篇 |
1991年 | 57篇 |
1990年 | 42篇 |
1989年 | 35篇 |
1988年 | 37篇 |
1987年 | 23篇 |
1986年 | 26篇 |
1985年 | 35篇 |
1984年 | 34篇 |
1983年 | 16篇 |
1982年 | 29篇 |
1981年 | 26篇 |
1980年 | 9篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1973年 | 5篇 |
排序方式: 共有9709条查询结果,搜索用时 15 毫秒
1.
2.
3.
Savita Verma Deepak M. Maher Samadhan S. Nagane Bhausaheb V. Tawade Prakash P. Wadgaonkar 《Journal of polymer science. Part A, Polymer chemistry》2019,57(5):588-597
New aromatic (co)polyesters containing pendant propargyloxy groups were synthesized by phase transfer‐catalyzed interfacial polycondensation of 5‐(propargyloxy)isophthaloyl chloride (P‐IPC) and various compositions of P‐IPC and isophthaloyl chloride with bisphenol A. FTIR and NMR spectroscopic data, respectively, revealed successful incorporation of pendant propargyloxy groups into (co)polyesters and formation of (co)polyesters with desired compositions. (Co)polyesters exhibited good solubility in common organic solvents such as chloroform, dichloromethane, and tetrahydrofuran and could be cast into transparent, flexible, and tough films from chloroform solution. Inherent viscosities and number average molecular weights of (co)polyesters were in the range 0.77–1.33 dL/g and 43,600–118,000 g/mol, respectively, indicating the achievement of reasonably high‐molecular weights. The 10% weight loss temperatures of (co)polyesters were in the range 390–420 °C, demonstrating their good thermal stability. (Co)polyesters exhibited Tg in the range 146–170 °C and Tg values decreased with increase in mol % incorporation of P‐IPC. The study of non‐isothermal curing by DSC indicated thermal crosslinking of (co)polyesters via propargyloxy groups. The utility of pendant propargyloxy group was demonstrated by post‐modification of the selected copolyester with 1‐(4‐azidobutyl)pyrene, 9‐(azidomethyl)anthracene, and azido‐terminated poly(ethyleneglycol) monomethyl ether via copper(I)‐catalyzed Huisgen 1,3‐dipolar cycloaddition reaction. FTIR and 1H NMR spectra confirmed that click reaction was quantitative. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 588–597 相似文献
4.
5.
This paper reports that the growth of RuOx(110) thin layer growth on Ru(0001)
has been investigated by means of scanning tunnelling microscope (STM). The STM
images showed a domain structure with three rotational domains of RuOx(110)
rotated by an angle of 120℃.
The as-grown RuOx(110) thin layer is expanded from the bulk-truncated
RuOx(110) due to the large mismatch between RuOx(110) and the
Ru(0001) substrate. The results also indicate that growth of RuOx(110)
thin layer on the Ru(0001) substrate by oxidation tends first to formation
of the Ru-O (oxygen) chains in the [001] direction of RuOx(110). 相似文献
6.
Kasper K. Berthelsen Jesper Møller 《Bulletin of the Brazilian Mathematical Society》2002,33(3):351-367
This primer provides a self-contained exposition of the case where spatial birth-and-death processes are used for perfect
simulation of locally stable point processes. Particularly, a simple dominating coupling from the past (CFTP) algorithm and
the CFTP algorithms introduced in [13], [14], and [5] are studied. Some empirical results for the algorithms are discussed.
Received: 30 June 2002 相似文献
7.
R. S. Martynov Yu. M. Nechepurenko 《Computational Mathematics and Mathematical Physics》2006,46(7):1155-1167
For a discrete linear stochastic dynamical system, computation of the response matrix to the external action from a subspace using given observational data is examined. An algorithm is proposed and substantiated that makes it possible to improve the numerical accuracy and to reduce the amount of observational data compared to the general case where an arbitrary external action is allowed. As an illustration, a discrete system arising in the analysis of a linear stochastic dynamical continuous-time system is considered more thoroughly. Some numerical results are presented. 相似文献
8.
用分子动力学方法对5%负失配条件下面心立方晶体铝薄膜的原子沉积外延生长进行了三维模拟.铝原子间的相互作用采用嵌入原子法(EAM)多体势计算.模拟结果再现了失配位错的形成现象.分析表明,失配位错在形成之初即呈现为Shockley扩展位错,即由两个伯格斯矢量为〈211〉/6的部分位错和其间的堆垛层错组成,两个部分位错的间距、即层错宽度为1.8 nm,与理论计算结果一致;外延晶体薄膜沉积生长中,位错对会发生滑移,但其间距保持稳定.进一步观察发现,该扩展位错产生于一种类似于“局部熔融-重结晶”的表层局部无序紊乱-
关键词:
失配位错
外延生长
薄膜
分子动力学
铝 相似文献
9.
10.
本文给出Riccati方程及另外一类具有代表性微分方程的亚纯解(n,1)级的上界估计,在一定条件下确立了文[2]中的猜测的正确性。 相似文献