全文获取类型
收费全文 | 1555篇 |
免费 | 41篇 |
国内免费 | 3篇 |
专业分类
化学 | 1301篇 |
晶体学 | 9篇 |
力学 | 7篇 |
数学 | 13篇 |
物理学 | 269篇 |
出版年
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 23篇 |
2018年 | 10篇 |
2017年 | 10篇 |
2016年 | 22篇 |
2015年 | 21篇 |
2014年 | 39篇 |
2013年 | 67篇 |
2012年 | 71篇 |
2011年 | 86篇 |
2010年 | 50篇 |
2009年 | 40篇 |
2008年 | 76篇 |
2007年 | 66篇 |
2006年 | 69篇 |
2005年 | 90篇 |
2004年 | 67篇 |
2003年 | 57篇 |
2002年 | 40篇 |
2001年 | 60篇 |
2000年 | 69篇 |
1999年 | 36篇 |
1998年 | 26篇 |
1997年 | 29篇 |
1996年 | 26篇 |
1995年 | 20篇 |
1994年 | 29篇 |
1993年 | 33篇 |
1992年 | 37篇 |
1991年 | 24篇 |
1990年 | 19篇 |
1989年 | 24篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 25篇 |
1984年 | 29篇 |
1983年 | 24篇 |
1982年 | 13篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 20篇 |
1978年 | 14篇 |
1977年 | 9篇 |
1976年 | 13篇 |
1975年 | 7篇 |
1974年 | 9篇 |
1973年 | 4篇 |
排序方式: 共有1599条查询结果,搜索用时 390 毫秒
191.
Jun Hosoi Tetsuo Oikawa Masao Inoue Yoshio Matsui Tadashi Endo 《Journal of Electron Spectroscopy and Related Phenomena》1982,27(3):243-254
An interband π plasmon and π* edge have been observed in the spectrum of hexagonal boron nitride (h-BN). This result is in good agreement with that 相似文献
192.
Kanehiro Nakamura Ryuichi Endo Masatami Takeda 《Journal of Polymer Science.Polymer Physics》1977,15(12):2095-2101
Molecular motions of hydrophobic–hydrophilic water-soluble block copolymers in solution were investigated by high-resolution proton magnetic resonance (NMR). Samples studied include block copolymers of polystyrene–poly(ethylene oxide), polybutadiene–poly(ethylene oxide), and poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide). NMR measurements were carried out varying molecular weight, temperature, and solvent composition. For AB copolymers of polystyrene and poly(ethylene oxide), two peaks caused by the phenyl protons of low-molecular-weight (M?n = 3,300) copolymer were clearly resolved in D2O at 100°C, but the phenyl proton peaks of high-molecular-weight (M?n = 13,500 and 36,000) copolymers were too broad to observe in the same solvent, even at 100°C. It is concluded that polystyrene blocks are more mobile in low-molecular-weight copolymer in water than in high-molecular-weight copolymer in the same solvent because the molecular weight of the polystyrene block of the low-molecular-weight copolymer is itself small. In the mixed solvent D2O and deuterated tetrahydrofuran (THF-d8), two peaks caused by the phenyl protons of the high-molecular-weight (M?n = 36,000) copolymer were clearly resolved at 67°C. It is thought that the molecular motions of the polystyrene blocks are activated by the interaction between these blocks and THF in the mixed solvent. 相似文献
193.
Xestospongin A,B,C and D represent a new class of macrocyclic 1-oxaquinolizidines, have been isolated from Australian sponge . The structure of xestospongin C has been determined by X-ray analysis. 相似文献
194.
195.
196.
197.
Makoto Yanaga Kazutoyo Endo Toshio Shimizu Hiromichi Nakahara Masashi Takahashi Masuo Takeda 《Hyperfine Interactions》1994,90(1):499-503
A systematic study of pentavalent organoantimony compounds, (RC6H4)3SbX2 (R=H,p-CH3,p-F,p-Cl,p-CF3,o-CH3; X=Cl, Br), was carried out to examine the effect on Mössbauer parameters of the substituent on the aromatic ring. The Mössbauer parameters obtained in polycrystalline form reflected the steric effect caused by the position of the substituent on the aromatic ring. On the other hand, measurements in frozen organic solutions revealed that the electron density and electric field gradient at and around the antimony nucleus became smaller when the more electron-attractive group was introduced into thepara position. 相似文献
198.
Masakatsu Saeki Masami Nakada Nobuyuki M. Masaki Zenko Yoshida Kazutoyo Endo Yoshitaka Minai Toshiyuki Yamashita Hiroshi Mutoh Masaaki Magara 《Hyperfine Interactions》1994,92(1):1177-1181
Experiments on the57Fe Mössbauer effect in frozen solutions were carried out in order to demonstrate the capabilities of a cryostat which was developed for the emission Mössbauer spectroscopy of237Np. We confirmed the existence of an aliovalent state of57Fe in the temperature range from 5.5 to 35 K. However, the relative amounts of Fe(II) and Fe(III) in the frozen matrix were almost constant for the temperature range from 5.5 to 150 K. The design, operation and capabilities of the cryostat are also described. 相似文献
199.
A. Suzuki R. Yamamoto M. Doyama H. Mizubayashi S. Okuda K. Endo S. Gonda 《Solid State Communications》1984,49(12):1173-1176
The temperature dependence of the resonant period in 1T-TaS2 was measured using the resonant flexural vibration technique. From the close study on the effect of thermal cycles, it is suggested that the anomalous regions observed both on cooling down (183–193 K) and on warming up (218–282 K) were associated with the nearly commensurate-commensurate charge density waves (CDW's) phase transition. 相似文献
200.
M. Taniguchi S. Suga M. Seki H. Sakamoto H. Kanzaki Y. Akahama S. Endo S. Terada S. Narita 《Solid State Communications》1984,49(9):867-870
Valence band photoemission spectra of black phosphorus have shown anomalous behavior at the excitation of 2p core-excitons. The intensity of the 2.7 ev peak shows a clear Fano type interference due to a direct recombination of core-excitons leaving one hole in valence bands. Besides, strong enhancement of the 10.8 eV peak is interpreted as due to a core-exciton induced resonance with two-hole final states. The role of core-excitons as intermediate states for photoemission processes is newly revealed in the experiments. 相似文献