全文获取类型
收费全文 | 1389篇 |
免费 | 23篇 |
国内免费 | 6篇 |
专业分类
化学 | 886篇 |
晶体学 | 11篇 |
力学 | 16篇 |
数学 | 86篇 |
物理学 | 419篇 |
出版年
2019年 | 12篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 13篇 |
2015年 | 22篇 |
2014年 | 17篇 |
2013年 | 68篇 |
2012年 | 59篇 |
2011年 | 67篇 |
2010年 | 26篇 |
2009年 | 36篇 |
2008年 | 83篇 |
2007年 | 72篇 |
2006年 | 79篇 |
2005年 | 87篇 |
2004年 | 59篇 |
2003年 | 59篇 |
2002年 | 40篇 |
2001年 | 25篇 |
2000年 | 24篇 |
1999年 | 24篇 |
1998年 | 25篇 |
1997年 | 17篇 |
1996年 | 22篇 |
1995年 | 13篇 |
1994年 | 18篇 |
1993年 | 13篇 |
1992年 | 20篇 |
1991年 | 17篇 |
1990年 | 17篇 |
1989年 | 15篇 |
1988年 | 15篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 27篇 |
1984年 | 35篇 |
1983年 | 16篇 |
1982年 | 26篇 |
1981年 | 26篇 |
1980年 | 15篇 |
1979年 | 15篇 |
1978年 | 20篇 |
1977年 | 20篇 |
1976年 | 16篇 |
1975年 | 16篇 |
1974年 | 9篇 |
1973年 | 17篇 |
1972年 | 6篇 |
1969年 | 8篇 |
1968年 | 8篇 |
排序方式: 共有1418条查询结果,搜索用时 15 毫秒
1.
2.
Yasuhiko Iwasaki Keiko Shimakata Nobuyuki Morimoto Kimio Kurita 《Journal of polymer science. Part A, Polymer chemistry》2003,41(1):68-75
To obtain a hydrogel‐like elastic membrane, we prepared semi‐interpenetrating polymer networks (IPNs) by the radical polymerization of methacrylates such as 2‐methacryloyloxyethyl phosphorylcholine (MPC), 2‐hydroxyethylmethacrylate, and triethyleneglycol dimethacrylate diffused into segmented polyurethane (SPU) membranes swollen with a monomer mixture. The values of Young's modulus for the hydrated semi‐IPN membranes were less than that for an SPU membrane because of higher hydration, but they were much higher than that for a hydrated MPC polymer gel (non‐SPU). According to a thermal analysis, the MPC polymer influenced the segment association of SPU. The diffusion coefficient of 8‐anilino‐1‐naphthalenesulfonic acid sodium salt from the semi‐IPN membrane could be controlled with different MPC unit concentrations in the membrane, and it was about 7 × 102 times higher than that of the SPU membrane. Fibroblast cell adhesion on the semi‐IPN membrane was effectively reduced by the MPC units. We concluded that semi‐IPNs composed of the MPC polymer and SPU may be novel polymer materials possessing attractive mechanical, diffusive‐release, and nonbiofouling properties. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 68–75, 2003 相似文献
3.
4.
K. Kawahta T. Tetsuka J. Fujita M. Nagatsu H. Ohnishi S. Okajima T. Iwasaki 《International Journal of Infrared and Millimeter Waves》1988,9(7):655-665
A 4-channel HCN laser scattering system has been developed and applied to the JIPP T-IIU tokamak. Main aim of this system is to study microturbulence excited in the plasma, especially in the high power ICRF heating experiment. The observed density fluctuations are in a frequency range of the electron diamagnetic drift wave and have broad frequency spectra. The main part of the wavenumber is found to satisfy the condition of
. In the heating experiments, deterioration of the energy confinement time is observed, and the density fluctuation level increases with the increase of the heating power. 相似文献
5.
Adachi I Aihara H Dijkstra HB Enomoto R Fujii H Fujii K Fujii T Fujimoto J Fujiwara N Hayashii H Higashi S Iida N Imanishi A Ikeda H Ishii T Itoh R Iwasaki H Iwata S Kajikawa R Kamae T Kato S Kawabata S Kichimi H Kishida T Kobayashi M Kuroda S Kusuki N Maruyama A Maruyama K Masuda H Matsuda T Miyamoto A Morimoto T Nakamura K Nitoh O Noguchi S Ochiai F Okuno H Okusawa T Ohshima T Ozaki H Sato T Sai F Shimonaka J Shimozawa K Shirahashi A Sugahara R Sugiyama A Suzuki S Suwada T Takahashi K 《Physical review letters》1988,60(2):97-100
6.
7.
Quantum yields, lifetimes and shapes of fluorescence from polymers containing the trans-1,2-dicarbazolylcyclobutane (DCZB) or carbazolyl structures were studied in N,N-dimethylformamide. No sandwich-type excimer formation was observed for DCZB polymers. The so-called second excimer observed in poly(9-vinylcarbazole) might also be produced in poly(9-ethyl-3-vinylcarbazole). 相似文献
8.
9.
A sensitive assay for acyl CoA-cholesterol acyltransferase (EC 2.3.1.26) in rat liver microsomal and mitochondrial preparations is described. The lowered cholesterol concentration in the enzyme reaction with oleoyl CoA is determined spectrofluorimetrically by using the cholesterol oxidase/peroxidase/p-hydroxyphenylpropionic acid system. The assay requires as little as 20 μg of protein in the enzyme preparation. 相似文献
10.
T Iwasaki H Yamazaki T Nishitani K Kondo T Sato 《Chemical & pharmaceutical bulletin》1992,40(1):122-126
A series of 2-aminoethanol derivatives was synthesized and their inhibitory activities against protein kinase C were investigated. Among these compounds, 2-endo-hexadecylamino-5-norbornene-2- exo-methanol (4h) and 2-endo-hexadecylamino-5-norbornene-2,3-exo-dimethanol (4i) inhibited protein kinase C at the IC50 values of 2 x 10(-5) and 1 x 10(-5) M, respectively, but not protein kinase A at a concentration of 1 x 10(-3) M. The structure-activity relationships are discussed. 相似文献