全文获取类型
收费全文 | 1875篇 |
免费 | 25篇 |
国内免费 | 2篇 |
专业分类
化学 | 1370篇 |
晶体学 | 35篇 |
力学 | 21篇 |
数学 | 79篇 |
物理学 | 397篇 |
出版年
2021年 | 14篇 |
2020年 | 14篇 |
2019年 | 17篇 |
2018年 | 16篇 |
2017年 | 13篇 |
2016年 | 25篇 |
2015年 | 24篇 |
2014年 | 30篇 |
2013年 | 71篇 |
2012年 | 78篇 |
2011年 | 90篇 |
2010年 | 69篇 |
2009年 | 43篇 |
2008年 | 94篇 |
2007年 | 123篇 |
2006年 | 97篇 |
2005年 | 94篇 |
2004年 | 78篇 |
2003年 | 87篇 |
2002年 | 100篇 |
2001年 | 40篇 |
2000年 | 47篇 |
1999年 | 22篇 |
1998年 | 25篇 |
1997年 | 40篇 |
1996年 | 25篇 |
1995年 | 26篇 |
1994年 | 22篇 |
1993年 | 16篇 |
1992年 | 19篇 |
1991年 | 27篇 |
1990年 | 21篇 |
1989年 | 13篇 |
1988年 | 16篇 |
1986年 | 18篇 |
1985年 | 34篇 |
1984年 | 27篇 |
1983年 | 17篇 |
1982年 | 20篇 |
1981年 | 19篇 |
1980年 | 27篇 |
1979年 | 23篇 |
1978年 | 20篇 |
1977年 | 22篇 |
1976年 | 19篇 |
1975年 | 19篇 |
1974年 | 15篇 |
1973年 | 12篇 |
1968年 | 13篇 |
1967年 | 10篇 |
排序方式: 共有1902条查询结果,搜索用时 15 毫秒
1.
Watanabe Sou Senzaki Tatsuya Shibata Atsuhiro Nomura Kazunori Takeuchi Masayuki Nakatani Kiyoharu Matsuura Haruaki Horiuchi Yusuke Arai Tsuyoshi 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(3):1273-1277
Journal of Radioanalytical and Nuclear Chemistry - Extraction chromatography flow-sheet employing octyl(phenyl)-N,N-diisobutylcarbonoylmethylphosphine oxide and bis(2-ethylhexyl) hydrogen phosphate... 相似文献
2.
Yasuyuki Agari Kiyofumi Sakai Yosikazu Kano Ryoki Nomura 《Journal of Polymer Science.Polymer Physics》2007,45(21):2972-2981
We prepared biodegradable poly(ethylene oxide) (PEO)/poly(L ‐lactic acid) (PLLA) graded blends by the dissolution–diffusion process, and discussed the biodegradability and tensile strength of the graded blends by comparing isotropic blend and PLLA only. All the graded blends were degraded more largely than the PLLA only and isotropic blend (PEO: 37.5 wt %), which had the same content as the total content of those graded blends. The graded blend having most excellent wide compositional gradient was degraded most largely with the enzyme. Thus, graded structure of the blends promoted their biodegradabilities large. It was considered that the dissolution of PEO with water increased the surface area attacked by the enzyme, while PEO caught PLLA oligomers to promote the biodegradation of PLLA. Then, the biodegradabilities of the graded blends were suppressed by the increasing crystallinity of PLLA. Furthermore, the strengths of all the graded blends were larger than those of the isotropic blend. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2972–2981, 2007 相似文献
3.
Sub-critical crack growth rates of soda-lime-silicate glass and less brittle glass with different fictive temperatures were compared using the DCDC method under both dry and humid atmospheres in order to investigate the origin of the unique mechanical features of the less brittle glass developed by Ito and his collaborators. In both dry and humid atmospheres, the crack velocity of the soda-lime-silicate glass was slower than that of the less brittle glass. For both glasses, the glass sample with higher fictive temperature showed a slower crack growth rate under both dry and humid atmospheres. These observations can be explained by the tendency for the plastic flow at the crack tip; the soda-lime-silicate glass is expected to show easier plastic flow under tension than the less brittle glass, and also the samples with higher fictive temperatures are expected to show easier plastic flow, leading to greater fracture toughness, KIC, and slower crack growth rate. 相似文献
4.
T Yamakawa H Matsukura Y Nomura M Yoshioka M Masaki H Igata S Okabe 《Chemical & pharmaceutical bulletin》1991,39(7):1746-1752
A series of N-substituted 2-[(2-imidazolylsulfinyl)methyl]anilines (3) was synthesized and evaluated for its biological activity against gastric H+/K(+)-ATPase prepared from rabbit stomach and gastric acid secretions in Heidenhain pouch dogs. Monoalkyl substituents on the nitrogen atom of the aniline moiety markedly inhibited the enzyme activity to the same degree as omeprazole, a representative H+/K(+)-ATPase inhibitor. Most of these compounds, administered at 3 mg/kg i.v. inhibited histamine-stimulated gastric acid secretion. The inhibitory activity of these derivatives on the enzymes at pH 6.0 was more potent than that at pH 7.4, and was distinctly correlated to stability in aqueous solution at pH 5.0. 相似文献
5.
6.
7.
8.
Thi Thi Nge Naruhito Hori Akio Takemura Hirokuni Ono Tsunehisa Kimura 《Journal of Polymer Science.Polymer Physics》2003,41(7):711-714
A high magnetic field of 5 T was used to fabricate a magnetically aligned, optically anisotropic, liquid‐crystalline chitin/poly(acrylic acid) composite. The aligned mesophase was fixed by photoinitiated free‐radical polymerization. From an examination of polarized optical micrographs and an X‐ray diffraction study, a high degree of orientation of 0.70 was observed for the composite with a higher liquid‐crystalline chitin concentration (10.70 wt %); the orientation was reduced with a decreased chitin concentration at a given acrylic acid concentration. The X‐ray data for the developed composite showed a uniplanar orientation for the chitin crystallites, with its molecular long axes perpendicular to the direction of the magnetic field. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 711–714, 2003 相似文献
9.
10.
K. M. A. Salam Hidekazu Konishi Masahiro Mizuno Hisashi Fukuda Shigeru Nomura 《Applied Surface Science》2002,190(1-4):88-95
Polycrystalline (1−x)Ta2O5−xTiO2 thin films were formed on Si by metalorganic decomposition (MOD) and annealed at various temperatures. As-deposited films were in the amorphous state and were completely transformed to crystalline after annealing above 600 °C. During crystallization, a thin interfacial SiO2 layer was formed at the (1−x)Ta2O5−xTiO2/Si interface. Thin films with 0.92Ta2O5–0.08TiO2 composition exhibited superior insulating properties. The measured dielectric constant and dissipation factor at 1 MHz were 9 and 0.015, respectively, for films annealed at 900 °C. The interface trap density was 2.5×1011 cm−2 eV−1, and flatband voltage was −0.38 V. A charge storage density of 22.8 fC/μm2 was obtained at an applied electric field of 3 MV/cm. The leakage current density was lower than 4×10−9 A/cm2 up to an applied electric field of 6 MV/cm. 相似文献