全文获取类型
收费全文 | 983篇 |
免费 | 23篇 |
国内免费 | 2篇 |
专业分类
化学 | 746篇 |
晶体学 | 11篇 |
力学 | 17篇 |
数学 | 18篇 |
物理学 | 216篇 |
出版年
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2016年 | 14篇 |
2015年 | 18篇 |
2014年 | 20篇 |
2013年 | 37篇 |
2012年 | 41篇 |
2011年 | 55篇 |
2010年 | 24篇 |
2009年 | 27篇 |
2008年 | 60篇 |
2007年 | 38篇 |
2006年 | 44篇 |
2005年 | 39篇 |
2004年 | 37篇 |
2003年 | 36篇 |
2002年 | 30篇 |
2001年 | 28篇 |
2000年 | 17篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 11篇 |
1995年 | 6篇 |
1994年 | 11篇 |
1993年 | 17篇 |
1992年 | 16篇 |
1991年 | 21篇 |
1990年 | 12篇 |
1989年 | 13篇 |
1988年 | 19篇 |
1987年 | 27篇 |
1986年 | 13篇 |
1985年 | 25篇 |
1984年 | 19篇 |
1983年 | 11篇 |
1982年 | 25篇 |
1981年 | 20篇 |
1980年 | 15篇 |
1979年 | 16篇 |
1978年 | 9篇 |
1977年 | 16篇 |
1976年 | 6篇 |
1975年 | 9篇 |
1974年 | 12篇 |
1973年 | 7篇 |
1971年 | 5篇 |
1968年 | 5篇 |
1967年 | 5篇 |
排序方式: 共有1008条查询结果,搜索用时 15 毫秒
111.
Akito Kobayashi Yoshiaki
no Tamifusa Matsuura Yoshihiro Kuroda 《Physica C: Superconductivity and its Applications》1998,300(3-4):287-300
Dynamical spin susceptibility χs(q,ω) of the d–p model in the over doping region is investigated by using the auxiliary boson technique. It includes higher order terms of the 1/N-expansion within the random phase approximation (RPA) of the local vertex, where frequency dependence of the quasi-particle interaction is taken into account. The incommensurate spin fluctuation is obtained due to the nesting effect in the low energy region (ωω*), whereas the commensurate one in the high energy region (ωω*), the characteristic energy ω* is estimated to be about 30 meV. Both of the spin–lattice relaxation rate 1/T1 and the spin–spin relaxation rate 1/Tg monotonically increase as T decreases, while the spin Knight shift K is almost independent of T. 相似文献
112.
Fumaric acid (FA) suppressed the carcinogenesis in the liver of rats fed 3'-methyl-4-(dimethylamino)azobenzene (3'-Me-DAB), and a study was performed to examine the effect of FA on deoxyribonucleic acid (DNA) synthesis and subcellular structures of hepatocytes under the anticarcinogenic regimens. Male Donryu strain rats were given 3'-Me-DAB by being fed a diet containing 0.06% 3'-Me-DAB for 50 d. They were then given a diet containing 1% FA and drinking water containing 0.025% FA for 53 to 69 weeks. Hepatocytes were isolated from the liver by the collagenase perfusion method and placed in culture, and their activity for DNA synthesis was measured in terms of the incorporation of [3H]dThd into DNA. An enhanced DNA synthesis of hepatocytes was noted in the rats given FA, indicating that FA enhanced the proliferation of hepatocytes to counteract the carcinogenic effect of 3'-Me-DAB. An electron microscopic examination indicated that the distribution of subcellular organella was almost normal in the FA-treated hepatocytes. 相似文献
113.
Until a few years ago, most scientists believed that the isotopic anomalies produced by the extinct radionuclides such as26Al and129I relative to normal abundances are all of the order of 10–4 despite the wide range in their mean lifetime and hence this anomaly range must be the result of inhomogenious mixing ofexotic materials with much larger quantities ofnormal solar system materials over a short time rather than the result of free decay. Re-examination of the existing aluminum isotope data for the mineral inclusions of the carbonaceous chondrite Murchison reveals, however, that the observed anomalies can be explained in a more straightforward manner as due to the formation of spallation-produced aluminum and magnesium isotopes from28Si during thex-process nucleosynthesis, which must have occurred on the surface of an exploding supernova more than 5 billion years ago. 相似文献
114.
Takeharu Innami Ryushi Fujimura Masahiro Nomura Tsutomu Shimura Kazuo Kuroda 《Optical Review》2005,12(6):448-450
The photorefractive effect was observed in He-ion-implanted semi-insulating GaN film in the UV spectral region. The photorefractive
grating is induced by the electroabsorption effect near the band-edge. Two beam coupling experiments were performed at a wavelength
of 363.8 nm. The experimental results indicate that absorption grating mainly contributes to the beam coupling. 相似文献
115.
116.
Yoshitane Imai Kensaku Kamon Nobuo Tajima Reiko Kuroda Yoshio Matsubara 《Tetrahedron》2007,63(48):11928-11932
Chiral charge-transfer (CT) complexes composed of a chiral 1,1′-bi-2-naphthol cluster as the electron donor and 1,1′-dibenzyl-4,4′-bipyridinium dichloride as the electron acceptor serve as a host system for molecular recognition. CT complexes that include guest alcohols show different diffuse reflectance spectra (DRS) depending on the included guest. 相似文献
117.
Motoo Tori Aki Watanabe Yasuko Okamoto Shigeru Takaoka Chiaki Kuroda Ryo Hanai 《Tetrahedron》2008,64(19):4486-4495
Twenty-six eremophilane-type sesquiterpenoids, including six new compounds, were isolated from the title species. One of the new compounds, kanaitzensol, suggested the presence of an enzyme for the conversion of eremophil-7(11)-en-8-one derivative to furanoeremophilanes. The plant was collected at 15 locations in Yunnan Province of China and found to be diverse with respect to its sesquiterpenoid composition. DNA sequencing also revealed a large intraspecific diversity of the plant. 相似文献
118.
119.
Urea (U) and salicylic acid (SA) crystallize from aqueous solution as a 11 adduct whose structure shows them to be linked via several weak and one strong hydrogen bonds. The ir spectra of the adduct and its deuterated counterpart have been analyzed and the stretching modes of the various hydrogen bonds identified. The1H and13C nmr. spectra are also interpreted to show that discrete adducts of U·SA persist in solution. On heating, U·SA decarboxylates at a much lower temperature than SA itself. 相似文献
120.