全文获取类型
收费全文 | 1579篇 |
免费 | 76篇 |
国内免费 | 7篇 |
专业分类
化学 | 1345篇 |
晶体学 | 12篇 |
力学 | 37篇 |
数学 | 57篇 |
物理学 | 211篇 |
出版年
2023年 | 11篇 |
2022年 | 24篇 |
2021年 | 31篇 |
2020年 | 31篇 |
2019年 | 29篇 |
2018年 | 22篇 |
2017年 | 21篇 |
2016年 | 52篇 |
2015年 | 49篇 |
2014年 | 68篇 |
2013年 | 117篇 |
2012年 | 141篇 |
2011年 | 155篇 |
2010年 | 91篇 |
2009年 | 62篇 |
2008年 | 119篇 |
2007年 | 106篇 |
2006年 | 95篇 |
2005年 | 105篇 |
2004年 | 77篇 |
2003年 | 66篇 |
2002年 | 82篇 |
2001年 | 21篇 |
2000年 | 20篇 |
1999年 | 12篇 |
1998年 | 18篇 |
1997年 | 9篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1979年 | 1篇 |
1973年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有1662条查询结果,搜索用时 15 毫秒
121.
Jae‐Hyun Lee Kyuri Lee Seung Ho Moon Yuhan Lee Tae Gwan Park Prof. Jinwoo Cheon Prof. 《Angewandte Chemie (International ed. in English)》2009,48(23):4174-4179
Cancer‐cell‐targeted gene silencing was observed with a magnetic‐nanoparticle platform (MEIO, magnetism‐engineered iron oxide) on which a fluorescent dye, siRNA, and a RGD‐peptide targeting moiety were attached (see picture). The different functionalities enable the macroscopic (magnetic resonance) and microscopic (fluorescence) imaging of target cells. This system may be suitable for concurrent diagnostic and therapeutic applications.
122.
Dr. S. S. Seung Prof. M. C. Harrison Prof. I. G. Csizmadia 《Theoretical chemistry accounts》1967,8(4):281-284
This part of the series presents the results obtained by open shell SCF computations on the G, N, O, and F Atoms.
Zusammenfassung Dieser Teil der Reihe gibt die Ergebnisse von SCF-Rechnungen für offene Schalen am C, N, O und F an.
Résumé Cette partie de la suite d'articles présente les résultats obtenus par des calculs SCF à couches ouvertes sur les atomet C, N, O et F.相似文献
123.
Kyukwan Zong Seung Il Shin Dong Ju Jeon Jung No Lee Eung K. Ryu 《Journal of heterocyclic chemistry》2000,37(1):75-78
3‐Aryl‐4‐methoxycarbonylisoxazoles were prepared from the reaction of a variety of substituted benzonitrile oxides with methyl 3‐(p‐nitrobenzoyloxy)acrylate in moderate to good yields. 相似文献
124.
Fine-sized ZnO–B2O3–CaO–Na2O–P2O5 glass powders with spherical shape were directly prepared by high temperature spray pyrolysis. The ZnO–B2O3–CaO–Na2O–P2O5 powders prepared by spray pyrolysis at temperatures above 1200 °C had broad peaks at around 30° in the XRD patterns. The glass transition temperatures (Tg) of the glass powders obtained by spray pyrolysis at preparation temperatures between 900 °C and 1400 °C were near 480 °C regardless of the preparation temperatures. The dielectric layers formed from the glass powders prepared by spray pyrolysis at preparation temperatures above 1300 °C had clean surface and dense inner structure at the firing temperature of 580 °C. The transmittance of the dielectric layer formed from the glass powders obtained by spray pyrolysis at preparation temperature of 1400 °C was 90% at the firing temperature of 580 °C, in which the thickness of the dielectric layer was 13 μm. The UV cutoff edges gradually shift towards longer wavelength with increasing the preparation temperature of glass powders and the firing temperature of dielectric layers. 相似文献
125.
Kim BJ Kim SY Cho YS Kim BJ Han BG Park EK Lee SH Kim HY Kim GS Lee JY Koh JM 《Experimental & molecular medicine》2011,43(2):71-81
There is increasing evidence of a biochemical link between lipid oxidation and bone metabolism. Paraoxonase 1 (PON1) prevents the oxidation of low-density lipoprotein (LDL) and metabolizes biologically active phospholipids in oxidized LDLs. Here, we performed association analyses of genetic variation in PON1 to ascertain its contribution to osteoporotic fractures (OFs) and bone mineral density (BMD). We directly sequenced the PON1 gene in 24 Korean individuals and identified 26 sequence variants. A large population of Korean postmenopausal women (n=1,329) was then genotyped for eight selected PON1 polymorphisms. BMD at the lumbar spine and femoral neck was measured using dual-energy X-ray absorptiometry. Lateral thoracolumbar (T4-L4) radiographs were obtained for vertebral fracture assessment, and the occurrence of non-vertebral fractures (i.e., wrist, hip, forearm, humerus, rib, and pelvis) was examined using self-reported data. Multivariate analyses showed that none of the polymorphisms was associated with BMD at either site. However, +5989A>G and +26080T>C polymorphisms were significantly associated with non-vertebral and vertebral fractures, respectively, after adjustment for covariates. Specifically, the minor allele of +5989A>G exerted a highly protective effect against non-vertebral fractures (OR=0.59, P=0.036), whereas the minor allele of +26080T>C was associated with increased susceptibility to vertebral fractures (OR=1.73, P=0.020). When the risk for any OFs (i.e., vertebral or non-vertebral) was considered, the statistical significance of both polymorphisms persisted (P=0.002-0.010). These results suggest that PON1 polymorphisms could be one of useful genetic markers for OF risk in postmenopausal women. 相似文献
126.
We consider the angle of inclination (with respect to the horizontal) of the profile of a steady 2D inviscid symmetric periodic or solitary water wave subject to gravity. There is an upper bound of 31.15° in the irrotational case [1] and an upper bound of 45° in the case of favorable vorticity [13]. On the other hand, if the vorticity is adverse, the profile can become vertical. We prove here that if the adverse vorticity is sufficiently small, then the angle still has an upper bound which is slightly larger than 45°. 相似文献
127.
128.
Polyhydroxyalkanoates (PHAs) are carbon and energy reserve material accumulated by numerous microorganisms and have been drawing much attention as biodegradable substitutes for conventional nondegradable plastics and elastomers. There are a number of different PHAs having a variety of material properties based on the different monomer composition. Poly(3‐hydroxybutyrate) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) are now efficiently produced by bacterial fermentation at reasonable production costs. Recent advances in the production of short‐chain‐length (SCL) PHAs by bacterial fermentation are reviewed. Current status of the production of medium‐chain‐length (MCL) PHAs and SCL‐MCL‐PHA copolymers is also reviewed. 相似文献
129.
Sang‐Wook Park Seung‐Hyeun Park Wonho Kim Dong‐Soo Suh In‐Joe Sohn 《Journal of polymer science. Part A, Polymer chemistry》2000,38(19):3543-3549
The phase‐transfer catalyzed graft copolymerization of methyl methacrylate onto polychloroprene was carried out using tricaprylylmethylammonium chloride as a phase‐transfer catalyst in a two‐phase system of an aqueous Na2S2O8 solution and toluene at 55 °C under a nitrogen atmosphere. The initial rate of graft copolymerization was expressed as the combined terms of quaternary onium cation and peroxydisulfate anion in the aqueous phase rather than the fed concentrations of catalyst and Na2S2O8. The observed initial rate of graft copolymerization was used to analyze the graft copolymerization mechanism with a cycle phase‐transfer initiation step in the heterogeneous liquid–liquid system. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3543–3549, 2000 相似文献