全文获取类型
收费全文 | 506篇 |
免费 | 16篇 |
国内免费 | 1篇 |
专业分类
化学 | 415篇 |
晶体学 | 3篇 |
力学 | 2篇 |
数学 | 26篇 |
物理学 | 77篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 1篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 14篇 |
2015年 | 10篇 |
2014年 | 7篇 |
2013年 | 32篇 |
2012年 | 45篇 |
2011年 | 48篇 |
2010年 | 22篇 |
2009年 | 25篇 |
2008年 | 46篇 |
2007年 | 23篇 |
2006年 | 36篇 |
2005年 | 29篇 |
2004年 | 25篇 |
2003年 | 34篇 |
2002年 | 35篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1974年 | 1篇 |
1968年 | 1篇 |
1939年 | 1篇 |
1938年 | 1篇 |
1921年 | 1篇 |
1909年 | 1篇 |
排序方式: 共有523条查询结果,搜索用时 31 毫秒
31.
32.
33.
[chemical reaction: see text]. Two novel insecticidal antibiotics with a p-methoxyphenylquinolinone skeleton fused with a pyran ring, yaequinolones J1 (1) and J2 (2), have been isolated from Penicillium sp. FKI-2140, and structures were elucidated by spectroscopic studies including various NMR experiments. The relative stereochemistries were assigned by NOE experiments. Yaequinolones J1 and J2 showed toxicity against Artemia salina (brine shrimp) with the MIC value of 6.25 microg/mL. 相似文献
34.
Eguchi K Enomoto S Furuno K Goldman J Hanada H Ikeda H Ikeda K Inoue K Ishihara K Itoh W Iwamoto T Kawaguchi T Kawashima T Kinoshita H Kishimoto Y Koga M Koseki Y Maeda T Mitsui T Motoki M Nakajima K Nakajima M Nakajima T Ogawa H Owada K Sakabe T Shimizu I Shirai J Suekane F Suzuki A Tada K Tajima O Takayama T Tamae K Watanabe H Busenitz J Djurcic Z McKinny K Mei DM Piepke A Yakushev E Berger BE Chan YD Decowski MP Dwyer DA Freedman SJ Fu Y Fujikawa BK Heeger KM Lesko KT Luk KB Murayama H 《Physical review letters》2003,90(2):021802
KamLAND has measured the flux of nu;(e)'s from distant nuclear reactors. We find fewer nu;(e) events than expected from standard assumptions about nu;(e) propagation at the 99.95% C.L. In a 162 ton.yr exposure the ratio of the observed inverse beta-decay events to the expected number without nu;(e) disappearance is 0.611+/-0.085(stat)+/-0.041(syst) for nu;(e) energies >3.4 MeV. In the context of two-flavor neutrino oscillations with CPT invariance, all solutions to the solar neutrino problem except for the "large mixing angle" region are excluded. 相似文献
35.
36.
Beloslav Riečan 《International Journal of Theoretical Physics》2000,39(3):851-858
A weakly -distributive product MV algebra M is considered as a base of aquantum structure model. A state is a morphism from M to the unit interval, andan observable is a morphism from the system of all Borel sets to M. It is provedthat the subspace L
p
of the space of observables is a complete pseudometricspace. This result generalizes the previous result; the proof is new. 相似文献
37.
Tadashi Nishio Rie Suzuki Yuko Tsukada Hideko Kanazawa Teruo Okano Takako Miyabe-Nishiwaki 《Journal of chromatography. A》2009,1216(44):7427-7432
A new method for the quantitative analysis of monkey serum propofol, which is widely used as an anaesthetic agent, was developed by utilizing a temperature-responsive polymer of N-isopropylacrylamide (NIPAAm) and butyl methacrylate (BMA) as the stationary phase of HPLC–fluorescence detection. This poly(NIPAAm-co-BMA) copolymer undergoes a reversible phase transition from a hydrophilic to a hydrophobic microstructure when triggered by change in the temperature. Also this chromatographic system is possible to separate the analytes by using only water as a mobile phase. A pretreatment of the serum (80 μL) was only solid-phase extraction, and the recovery rate of propofol and internal standard was more than 77%, respectively. This method covered the calibration range from 0.5 μg/mL to 10 μg/mL and allowed a reproducible quantification of the serum propofol in administrated monkey serum. The intra- and inter-assay relative standard deviations were less than 14.1%. In addition, there was good relationship of the quantification values between the developed method and the widely used reversed-phase HPLC method. Our developed method has proven to be useful for a simple analysis of propofol in clinical practice, because the avoidance of complicated mobile phase preparation was possible, and only temperature changing could regulate the retention time of the analyte. In addition, by using water instead of fossil fuel, it is the ideal analytical method according to green chemistry. 相似文献
38.
39.
Yoshimune Nonomura Takaharu Fujii Yuichiro Arashi Taku Miura Takashi Maeno Kaoru Tashiro Yasuhisa Kamikawa Rie Monchi 《Colloids and surfaces. B, Biointerfaces》2009,69(2):1-267
Water has a unique touch as well as characteristic physical properties. However, nobody knows the real identity of its touch. Here, we show that water creates a stick-slip feel when a small amount is rubbed using fingertip on an artificial skin that mimics the structure of human skin. The results of frictional analyses predict that this stick-slip feel is caused by a drastic change in frictional resistance. The present result is valuable for biologists and robot engineers as well as cognitive scientists and tribologists, because it is a new example of stick-slip phenomena on biological surfaces. The tactile texture of this most familiar material could also be applied to consumer products or virtual reality systems. 相似文献
40.