全文获取类型
收费全文 | 1609篇 |
免费 | 25篇 |
专业分类
化学 | 1171篇 |
晶体学 | 20篇 |
力学 | 9篇 |
数学 | 135篇 |
物理学 | 299篇 |
出版年
2021年 | 12篇 |
2020年 | 11篇 |
2019年 | 17篇 |
2016年 | 24篇 |
2015年 | 24篇 |
2014年 | 22篇 |
2013年 | 70篇 |
2012年 | 60篇 |
2011年 | 57篇 |
2010年 | 51篇 |
2009年 | 52篇 |
2008年 | 107篇 |
2007年 | 92篇 |
2006年 | 87篇 |
2005年 | 90篇 |
2004年 | 59篇 |
2003年 | 57篇 |
2002年 | 81篇 |
2001年 | 27篇 |
2000年 | 24篇 |
1999年 | 25篇 |
1998年 | 20篇 |
1997年 | 23篇 |
1996年 | 21篇 |
1995年 | 13篇 |
1994年 | 18篇 |
1993年 | 15篇 |
1992年 | 23篇 |
1991年 | 14篇 |
1990年 | 14篇 |
1989年 | 14篇 |
1988年 | 17篇 |
1987年 | 17篇 |
1986年 | 16篇 |
1985年 | 27篇 |
1984年 | 36篇 |
1983年 | 11篇 |
1982年 | 35篇 |
1981年 | 30篇 |
1980年 | 26篇 |
1979年 | 18篇 |
1978年 | 17篇 |
1977年 | 16篇 |
1976年 | 17篇 |
1975年 | 29篇 |
1974年 | 10篇 |
1973年 | 12篇 |
1972年 | 9篇 |
1971年 | 14篇 |
1968年 | 7篇 |
排序方式: 共有1634条查询结果,搜索用时 375 毫秒
41.
Zhang ZB Fujiki M Motonaga M McKenna CE 《Journal of the American Chemical Society》2003,125(26):7878-7881
The chiral ordering in aggregated poly(3-alkylthiophene) can be controlled by a metal salt-dependent doping-dedoping process. Enhancement or reduction in the chiral anisotropy factor depends on the doping level, such that doping driven by polymer-metal salt interactions, and dedoping driven by aggregate formation must be balanced in order to achieve maximal chiral ordering. This phenomenon provides a new basis to control chiral arrangement in conjugated polymer aggregates, relying solely on doping, and thus avoiding tedious modification of side-chain or main-chain structures. 相似文献
42.
43.
Shimon?Tanaka Hideya?Kawasaki Masao?Suzuki Masahiko?Annaka Norio?Nemoto Mats?Almgren Hiroshi?MaedaEmail author 《Colloid and polymer science》2004,282(10):1140-1145
Vesicle formation in a mixture of oleyldimethylamine oxide (OleylDMAO) and sodium oleate (NaOl) was investigated by viscoelastic measurements and cryoscopic transmission electron micrograph (cryo-TEM) observations. The viscoelastic properties changed with increasing mole fraction of NaOl (X
NaOl) from the Maxwell behavior of OleylDMAO solutions (X
NaOl=0) suggesting a transient network of long flexible chains. For X
NaOl=0.2 and 0.4 mixtures, both the shear storage modulus G and the shear loss modulus G showed weak dependences on angular frequency with a relation G>G. From cryo-TEM observations, vesicles coexisted with threadlike micelles in mixtures of X
NaOl=0.2 and 0.3. As X
NaOl increased further (X
NaOl=0.5 and 0.6), threadlike micelles disappeared and the coexistence of vesicles and globular micelles was observed. At X
NaOl=0.5, the viscosity decreased remarkably, which was consistent with the disappearance of threadlike micelles. The results indicated that vesicles were formed by the addition of NaOl to OleylDMAO solutions, contrary to the expectation of a decrease of the packing parameter with the introduction of electric charges. 相似文献
44.
45.
K. Nagamine Y. Miyake P. Birrer K. Shimomura M. Iwasaki T. Kuga J. Marangos 《Hyperfine Interactions》1994,87(1):1083-1089
A concept, a construction and an account of commissioning experiments up to May 1993 are given for the recently completed ultra-slow positive muon facility at the pulsed muon facility of UT-MSL/KEK. The intense and ultra-slow
+ beam with an extremely small phase-space volume to be produced in this facility will open new muon sciences includingSR studies on material surfaces. 相似文献
46.
Fine particles of -FeO(OH) were prepared using the56Fe isotope and the surfaces of the particles were coated with extremely thin57Fe(III) layers. Mössbauer results show that the Fe(III) ions in the top surface layer are involved in the magnetic order and occupy two kinds of surface sites. Both of the two exchange field at surface sites, estimated from the temperature dependences of the hyperfine fields, are smaller than the bulk value. The decrease of exchange fields at the surface sites corresponds to the reduced number of neighboring magnetic ions at each site. 相似文献
47.
K. Nagamine Y. Miyake P. Birrer K. Shimomura M. Iwasaki K. Nishiyama P. Strasser T. Kuga J. Marangos 《Hyperfine Interactions》1993,80(1-4):1287-1295
A concept, a design, a construction and an account of commissioning experiments are given for the recently completed ultra-slow muon facility at the pulsed muon facility of UT-MSL/KEK. The intense (more than 103/s) slow + beam with an extremely narrow phase-space volume (0.2 eV×(3 cm)2) to be produced in this facility will open a new muon science including surface physics and chemistry and fundamental atomic physics.Post-doctoral fellow of Swiss National Science Foundation. 相似文献
48.
Akchurin N Langland J Onel Y Bonner BE Corcoran MD Cranshaw J Nessi-Tedaldi F Nessi M Nguyen C Roberts JB Skeens J White JL Bravar A Giacomich R Penzo A Schiavon P Zanetti A Bystricky J Lehar F de Lesquen A van Rossum L Cossairt JD Read AL Derevschikov AA Matulenko YA Meschanin AP Nurushev SB Patalakha DI Rykov VL Solovyanov VL Vasiliev AN Grosnick DP Hill DA Laghai M Lopiano D Ohashi Y Shima T Spinka H Stanek RW Underwood DG Yokosawa A Funahashi H Goto Y Imai K Itow Y Makino S Masaike A 《Physical review D: Particles and fields》1993,48(7):3026-3036
49.
50.
Masao Tokuda Yasufumi Yamada Toshiya Takagi Hiroshi Suginome Akio Furusaki 《Tetrahedron letters》1985,26(49):6085-6088
Neutral aminyl radicals generated by anodic oxidation of lithium alkenylamides 2 undergo a stereoselective cyclization to give -1-methyl-2,5-disubstituted pyrrolidines 4. Their stereochemistry was confirmed by a comparison with -1,2-dimethyl-5-phenylpyrrolidine, the structure of which was established by X-ray crystallographic analysis of its quarternary ammonium bromide 6. 相似文献