全文获取类型
收费全文 | 1364篇 |
免费 | 177篇 |
国内免费 | 232篇 |
专业分类
化学 | 893篇 |
晶体学 | 12篇 |
力学 | 116篇 |
综合类 | 22篇 |
数学 | 142篇 |
物理学 | 588篇 |
出版年
2024年 | 5篇 |
2023年 | 28篇 |
2022年 | 33篇 |
2021年 | 23篇 |
2020年 | 19篇 |
2019年 | 28篇 |
2018年 | 46篇 |
2017年 | 17篇 |
2016年 | 33篇 |
2015年 | 37篇 |
2014年 | 37篇 |
2013年 | 30篇 |
2012年 | 104篇 |
2011年 | 109篇 |
2010年 | 43篇 |
2009年 | 51篇 |
2008年 | 91篇 |
2007年 | 107篇 |
2006年 | 106篇 |
2005年 | 89篇 |
2004年 | 87篇 |
2003年 | 70篇 |
2002年 | 41篇 |
2001年 | 43篇 |
2000年 | 43篇 |
1999年 | 37篇 |
1998年 | 34篇 |
1997年 | 32篇 |
1996年 | 40篇 |
1995年 | 36篇 |
1994年 | 28篇 |
1993年 | 32篇 |
1992年 | 31篇 |
1991年 | 29篇 |
1990年 | 22篇 |
1989年 | 26篇 |
1988年 | 15篇 |
1987年 | 9篇 |
1986年 | 12篇 |
1985年 | 10篇 |
1984年 | 16篇 |
1983年 | 4篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1977年 | 3篇 |
1971年 | 2篇 |
1966年 | 2篇 |
1956年 | 2篇 |
1955年 | 3篇 |
1948年 | 2篇 |
排序方式: 共有1773条查询结果,搜索用时 15 毫秒
81.
Theoretical Analysis of Interference Nanolithography of Surface Plasmon Polaritons without a Match Layer
下载免费PDF全文
![点击此处可从《中国物理快报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Interference nanolithography techniques based on long-range surface plasmon polaritons (LR-SPP) are hardly ever achieved by experiments at present. One key reason is that suitable liquid materials are difflcult to find as the match layer connects the metal film and the resist. We redesign a Kretschmann-Raether structure for interference lithography. A polymer layer is coated under the metal film, and an air layer is placed between the polymer layer and the resist layer. This design not only avoids the above-mentioned question of the match layer, but also can form a soft contact between the polymer layer and the resist layer and can protect the exposure pattern. Simulation results confirm that a device with an appropriately thick polymer layer can form high intensity and contrast interference fringes with a critical dimension of about λ/7 in the resist. In addition, the fabrication of the device is very easy. 相似文献
82.
Ishida K Ozaki D Kamatsuka T Tou H Kyogaku M Kitaoka Y Tateiwa N Sato NK Aso N Geibel C Steglich F 《Physical review letters》2002,89(3):037002
We report (27)Al Knight shift ( (27)K) measurement on a single-crystal UNi(2)Al(3) that reveals a coexistence of superconductivity and a spin-density-wave (SDW) type of magnetic ordering ( T(SDW) = 4.5 K). The spin part of (27)K, (27)K(s), does not change down to 50 mK across the superconducting (SC) transition temperature T(c) approximately 0.9 K. In contrast with the isostructural compound UPd(2)Al(3) ( T(c) approximately 2 K), which was identified to be a spin-singlet d-wave superconductor, the behavior of (27)K strongly supports that UNi(2)Al(3) , like UPt(3) and Sr(2)RuO(4), belongs to a class of spin-triplet SC pairing state superconductors. 相似文献
83.
84.
The fluoroquinolone antibiotic lomefloxacin is phototoxic, photogenotoxic, photomutagenic and photosensitizes tumorigenesis in mouse skin. We have used T4 endonuclease V to demonstrate that lomefloxacin photosensitizes pyrimidine dimer formation in a human keratinocyte line (HaCaT). A possible mechanism for this effect would be triplet-triplet energy transfer. However, there is indirect evidence that the lomefloxacin triplet yield is very low, making this reaction less likely. The finding that lomefloxacin photosensitizes production of highly mutagenic pyrimidine dimers correlates with its ability to initiate skin tumor formation in mice. Until the potential of other fluoroquinolones to photosensitize dimer formation is explored it may be unadvisable to prescribe these antibiotics to patients with defective DNA repair capacity (e.g. xeroderma pigmentosum). 相似文献
85.
Glycoconjugates constitute a major group of biomolecules, which participate in several biological functions and processes. Their carbohydrate components play key roles in determining the properties of glycoconjugates and, therefore, analysis and structural characterization of carbohydrates are essential. Capillary electrophoresis, due to its high resolving power and sensitivity, has been successfully used for the analysis of carbohydrates. In this review the principles of high-performance capillary electrophoresis; mechanisms employed for glycoconjugate analysis as well as the various detection techniques used are summarized. 相似文献
86.
Co(1,10-phen·)32+-KIO4-鲁米诺化学发光体系与应用 总被引:2,自引:0,他引:2
本文研究了Co(1,10-phen·)32+配合物对KIO4氧化鲁米诺所产生的强化学发光反应.以1,10-phen·为配位体时,Co(Ⅱ)的检出限为8×10-8g/L,工作曲线响应浓度范围在1×10-6~1×10-4g/L,测定1×10-4g/LCo(Ⅱ)离子的相对标准偏差为2.5%.配合物化学发光法检测啤酒、维生素B12针剂中微量Co(Ⅱ)可获得满意结果. 相似文献
87.
We experimentally demonstrate the first quantum system entangled in every degree of freedom (hyperentangled). Using pairs of photons produced in spontaneous parametric down-conversion, we verify entanglement by observing a Bell-type inequality violation in each degree of freedom: polarization, spatial mode, and time energy. We also produce and characterize maximally hyperentangled states and novel states simultaneously exhibiting both quantum and classical correlations. Finally, we report the tomography of a 2 x 2 x 3 x 3 system (36-dimensional Hilbert space), which we believe is the first reported photonic entangled system of this size to be so characterized. 相似文献
88.
Langford NK Dalton RB Harvey MD O'Brien JL Pryde GJ Gilchrist A Bartlett SD White AG 《Physical review letters》2004,93(5):053601
We produce and holographically measure entangled qudits encoded in transverse spatial modes of single photons. With the novel use of a quantum state tomography method that only requires two-state superpositions, we achieve the most complete characterization of entangled qutrits to date. Ideally, entangled qutrits provide better security than qubits in quantum bit commitment: we model the sensitivity of this to mixture and show experimentally and theoretically that qutrits with even a small amount of decoherence cannot offer increased security over qubits. 相似文献
89.
The first total synthesis of (+)-dragmacidin F has been accomplished, establishing the absolute configuration of this biologically important, antiviral marine alkaloid. The convergent route described features a palladium-mediated oxidative pyrrole carbocylization reaction to construct the [3.3.1] bicycle, as well as a highly selective Suzuki coupling to build the carbon skeleton of the natural product. A late-stage Neber rearrangement allows for the facile installation of the aminoimidazole moiety to provide (+)-dragmacidin F. 相似文献
90.
An "arrested" chloride abstraction occurs in the reaction of trans-RuCl(2)(DMeOPrPE)(2) with TlPF(6); the product is a 1-D coordination polymer in which the Tl(I) centers have an unusual octahedral coordination geometry with a stereochemically active 6s(2) lone pair. 相似文献