全文获取类型
收费全文 | 1476篇 |
免费 | 41篇 |
国内免费 | 4篇 |
专业分类
化学 | 1246篇 |
晶体学 | 12篇 |
力学 | 16篇 |
数学 | 31篇 |
物理学 | 216篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 15篇 |
2020年 | 12篇 |
2019年 | 17篇 |
2018年 | 14篇 |
2017年 | 6篇 |
2016年 | 17篇 |
2015年 | 29篇 |
2014年 | 33篇 |
2013年 | 79篇 |
2012年 | 69篇 |
2011年 | 75篇 |
2010年 | 45篇 |
2009年 | 35篇 |
2008年 | 80篇 |
2007年 | 105篇 |
2006年 | 99篇 |
2005年 | 77篇 |
2004年 | 88篇 |
2003年 | 68篇 |
2002年 | 66篇 |
2001年 | 43篇 |
2000年 | 34篇 |
1999年 | 31篇 |
1998年 | 24篇 |
1997年 | 22篇 |
1996年 | 18篇 |
1995年 | 13篇 |
1994年 | 21篇 |
1993年 | 13篇 |
1992年 | 19篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 11篇 |
1988年 | 10篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 29篇 |
1984年 | 20篇 |
1983年 | 14篇 |
1982年 | 15篇 |
1981年 | 23篇 |
1980年 | 17篇 |
1979年 | 15篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 6篇 |
1975年 | 10篇 |
1969年 | 4篇 |
排序方式: 共有1521条查询结果,搜索用时 15 毫秒
111.
Shinichi Kinugasa Hisae Nakahara Jun-Ichi Kawahara Yoshinori Koga Haruo Takaya 《Journal of Polymer Science.Polymer Physics》1996,34(3):583-586
Static light scattering measurements were performed on dilute solutions of monodisperse poly(ethylene oxide) (PEO) in methanol at 25°C. PEOs of five different molecular weights ranging from nominal Mw = 8.6 × 104 to 9.13 × 105 were used. Linear Zimm plots were obtained for all the PEO samples: no downturn was observed at small angles, indicating that no large aggregates of PEO molecules exist in the solution. From the plots, values of the weight-average molecular weight, Mw, the radius gyration, RG, and the second virial coefficient, A2, were successfully determined for respective PEOs. Observed relationship between RG and Mw indicates that methanol is certainly a good solvent for the polymer. © 1996 John Wiley & Sons, Inc. 相似文献
112.
113.
114.
Hironao Nakayama Masako Nakahara Erina Matsugi Midori Soda Tomoka Hattori Koki Hara Ayuki Usami Chiaki Kusumoto Shigeki Higashiyama Kiyoyuki Kitaichi 《Molecules (Basel, Switzerland)》2021,26(1)
Ferulic Acid (FA) is a highly abundant phenolic phytochemical which is present in plant tissues. FA has biological effects on physiological and pathological processes due to its anti-apoptotic and anti-oxidative properties, however, the detailed mechanism(s) of function is poorly understood. We have identified FA as a molecule that inhibits apoptosis induced by hydrogen peroxide (H2O2) or actinomycin D (ActD) in rat pheochromocytoma, PC12 cell. We also found that FA reduces H2O2-induced reactive oxygen species (ROS) production in PC12 cell, thereby acting as an anti-oxidant. Then, we analyzed FA-mediated signaling responses in rat pheochromocytoma, PC12 cells using antibody arrays for phosphokinase and apoptosis related proteins. This FA signaling pathway in PC12 cells includes inactivation of pro-apoptotic proteins, SMAC/Diablo and Bad. In addition, FA attenuates the cell injury by H2O2 through the inhibition of phosphorylation of the extracellular signal-regulated kinase (ERK). Importantly, we find that FA restores expression levels of brain-derived neurotrophic factor (BDNF), a key neuroprotective effector, in H2O2-treated PC12 cells. As a possible mechanism, FA increases BDNF by regulating microRNA-10b expression following H2O2 stimulation. Taken together, FA has broad biological effects as a neuroprotective modulator to regulate the expression of phosphokinases, apoptosis-related proteins and microRNAs against oxidative stress in PC12 cells. 相似文献
115.
116.
117.
118.
119.
120.
Sato S Ogura Y Miyanaga A Sugimoto T Tanaka K Moriyama H 《Journal of chromatography. A》2002,956(1-2):53-58
Ion chromatography (IC) has been a powerful tool for measuring ionic species in environmental samples such as tap, river and drain waters. Suppressor modules (membrane and disposable column types) have been used for reducing the background of a baseline. A new type of suppressor device, which has a suppressor resin and switching valve was developed. Fresh ionic resin is introduced into a groove for each analysis to perform the suppression of the working eluent. The eluent composition for obtaining higher sensitivity and better resolutions among ionic species and carbonate ion was also investigated. Although carbonate buffers are used for ion separation in general, the separation of carbonate ion from other ions was not achieved. A borate eluent resulted in good resolutions and higher sensitivity. A new column was also developed for obtaining higher column efficiency and resolution. The optimization of anion separation using a new IC system (IC-2001) that consists of a new suppressor device, an anion-exchange column (TSKgel SuperIC-Anion, 150x4.6 mm), an autosampler, a conductivity cell and a pump in a compact module is described. 相似文献