全文获取类型
收费全文 | 1073篇 |
免费 | 19篇 |
国内免费 | 8篇 |
专业分类
化学 | 779篇 |
晶体学 | 10篇 |
力学 | 22篇 |
数学 | 54篇 |
物理学 | 235篇 |
出版年
2023年 | 8篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 8篇 |
2019年 | 7篇 |
2018年 | 7篇 |
2016年 | 9篇 |
2015年 | 11篇 |
2014年 | 23篇 |
2013年 | 33篇 |
2012年 | 44篇 |
2011年 | 49篇 |
2010年 | 23篇 |
2009年 | 32篇 |
2008年 | 65篇 |
2007年 | 59篇 |
2006年 | 62篇 |
2005年 | 52篇 |
2004年 | 48篇 |
2003年 | 48篇 |
2002年 | 30篇 |
2001年 | 33篇 |
2000年 | 25篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 14篇 |
1994年 | 20篇 |
1993年 | 16篇 |
1992年 | 35篇 |
1991年 | 20篇 |
1990年 | 19篇 |
1989年 | 10篇 |
1988年 | 16篇 |
1987年 | 20篇 |
1986年 | 24篇 |
1985年 | 27篇 |
1984年 | 18篇 |
1983年 | 13篇 |
1982年 | 19篇 |
1981年 | 19篇 |
1980年 | 12篇 |
1979年 | 19篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1973年 | 5篇 |
1970年 | 4篇 |
排序方式: 共有1100条查询结果,搜索用时 781 毫秒
101.
On the basis of the theory developed in a previous paper (Part I), the angle and speed distributions of D2 molecules desorbing thermally from the Ni(111) surface are numerically calculated in the present paper (Part II). The dynamical motion of the activated complex of the recombinative desorption process is calculated by using a model potential surface, which involves a few parameters introduced to describe the necessary features of the potential surface at the transition state. Numerical calculations are carried out, and the results show that the present dynamical theory reproduces very well a variety of the characteristic features of the experimental results, e.g., sharply focused angular distribution, mean translational energy lower than 2k
B
T at grazing angle, and the non-Maxwellian profile of the TOF distribution. 相似文献
102.
Two-dimensional (2D) nano-objects, such as metallic nanofilms are the most fundamental building blocks for nanoelectronics devices. However, the fabrication of highly ordered nanofilms has been difficult because of well known Stranski-Krastanov growth, which results in rough growth front and high density grains. Here we report on the unusual high-quality film growth of Bi on a Si surface with atomic-level surface/interface smoothness and high film crystallinity. The formation of a newly discovered 2D allotrope was clarified to initiate its strong 2D growth. Above several-monolayer thickness, the 2D allotrope transforms into a single-crystalline film with bulk-like layered structure. Our study unveils the atomistic growth process of nano-sized Bi, and the obtained knowledge here will be generally applicable for the fabrication of various nano-devices using this intriguing material that shows rich thermal, magnetic, electronic properties in nanometer scale. 相似文献
103.
K. Asayama Y. Kitaoka G. -Q. Zheng K. Ishida Y. Tokunaga H. Mukuda T. Ohno 《Applied magnetic resonance》2000,19(3-4):305-319
This paper introduces nuclear magnetic resonance works in the strongly correlated super-conductors: heavy-Fermion, high-T C superconductors and Sr2RuO4. The analyses strongly support the spin-fluctuation-mediated superconductivity model in a high-T C superconductor. 相似文献
104.
In this review, we present recent advancements and novel developments in fluidic systems for applied analytical purposes in chemistry, biochemistry, and life science in general that employ and reflect the full benefits of microfluidics. A staggering rise in publications related to integrated, all‐in‐one microfluidic chips capable of separation, reaction, and detection have been observed, all of which realise the principal of micro total analysis systems or lab‐on‐a‐chip. These integrated chips actively adopt the scaling law concepts, utilising the highly developed fabrication techniques. Their aim is to multi‐functionalise and fully automate devices believed to assist the future advancements of point‐of‐care, clinical, and medical diagnostics. 相似文献
105.
We have demonstrated that hot water extracts of sclerotia of Sclerotinia sclerotiorum IFO 9395 (TSHW) show various immunomodulating activities and mitogenic substance(s) were recovered from the beta-1,3-glucanase resistant-fraction (EDP) (Shinohara et al. Chem. Pharm. Bull., 37, 2174 (1989]. In this paper, we examined whether or not the mitogenic substance(s) were also obtained from the other methods, phosphate buffer extraction. Although the native extracts (3S-M) sterilized with a membrane filter showed a slight mitogenicity to murine splenocytes, 3S-M denatured in boiling water (3S-MB) showed significant activity. Treatment of 3S-M for only 1 min in boiling water or 10 min at 70 degrees C was sufficient to show significant mitogenic activity. After heat treatment of 3S-M in boiling water for 30 s, the main band corresponding to that of 3S-M was not clearly observed. Instead, new bands appeared at the top of the gel in normal-polyacrylamide gel electrophoresis (normal-PAGE), suggesting that many physicochemical changes occurred during the heat treatment. These findings suggest that heat denaturation of the substance(s) from sclerotia was one of the triggering mechanisms expressing mitogenic activity to murine splenocytes. 相似文献
106.
Takashi Aoki Yasuhiro Kombu Yasuo Ohno 《Proceedings of the American Mathematical Society》2008,136(2):387-395
A generating function for specified sums of multiple zeta values is defined and a differential equation that characterizes this function is given. As applications, some relations for multiple zeta values over the field of rational numbers are discussed.
107.
Keiji Izuchi Shû ichi Ohno 《Proceedings of the American Mathematical Society》2006,134(5):1359-1364
We study Hankel-type operators on the space of bounded harmonic functions on the open unit disk. These operators are related to tight uniform algebras, the Dunford-Pettis property, and Bourgain algebras.
108.
As a chemiluminescent chemosensor that emits yellow light on reacting with a superoxide radical anion (O2−) and has a lipophilic character, a 6-phenylimidazo[1,2-a]pyrazin-3(7H)-one derivative possessing a boradiazaindacene (BODIPY) at the para position of 6-phenyl (1) was synthesized. The lipophilicity of 1 was investigated by reversed-phase liquid chromatography, and its log Pow value was found to be 3.57. This value was much higher than that of 2-methyl-6-(4-methoxypheyl)imidazo[1,2-a]pyrazin-3(7H)-one (MCLA, log Pow=1.19) and 6-[4-[2-{N′-(5-fluoresceinyl)thioureido}ethoxy]phenyl]-2-methylimidazo[1,2-a]pyrazin-3(7H)-one (FCLA, log Pow=−0.08), and it was comparable to that of benzenoid hydrocarbons. The O2−-induced chemiluminescence of 1 was investigated using the hypoxanthine/xanthine oxidase system as the source of O2−, and as a result, yellow emission was observed. The maximum wavelength was observed at 542 nm, and it was longer than that of FCLA. 相似文献
109.
Maeda S Matsuda Y Mizutani S Fujii A Ohno K 《The journal of physical chemistry. A》2010,114(44):11896-11899
The dynamics on the vacuum-ultraviolet one-photon ionization of a formamide-water cluster is investigated by a combination of theoretical reaction-path search and infrared spectroscopic methods. A keto-enol tautomerization of the formamide moiety occurs after photoionization by a catalytic action of the water molecule accompanied with its long-distance migration; the water molecule in the cluster migrates almost one turn around the formamide moiety. During the migration, the water molecule abstracts the proton of CH in the formamide moiety and carries it to the O atom side in the carbonyl group through a "catch and release"-type catalytic action. 相似文献
110.
Tanaka H Kawai T Adachi Y Ohno N Takahashi T 《Chemical communications (Cambridge, England)》2010,46(43):8249-8251
In this report, we describe the convergent synthesis of β(1,3) oligosaccharides containing an aminoalkyl group. The branched heptadecasaccharide and linear hexadecasaccharide acted as ligands of dectin-1 whose binding affinity was only 10-fold weaker than that of natural SPG and exhibited dectin-1 agonist activity. 相似文献