全文获取类型
收费全文 | 277篇 |
免费 | 9篇 |
国内免费 | 5篇 |
专业分类
化学 | 179篇 |
晶体学 | 4篇 |
力学 | 5篇 |
数学 | 55篇 |
物理学 | 48篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 10篇 |
2020年 | 10篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 11篇 |
2014年 | 11篇 |
2013年 | 23篇 |
2012年 | 19篇 |
2011年 | 11篇 |
2010年 | 13篇 |
2009年 | 8篇 |
2008年 | 15篇 |
2007年 | 23篇 |
2006年 | 9篇 |
2005年 | 16篇 |
2004年 | 16篇 |
2003年 | 12篇 |
2002年 | 16篇 |
2001年 | 3篇 |
2000年 | 10篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
排序方式: 共有291条查询结果,搜索用时 437 毫秒
281.
The effects of both the deposition temperature and the HfO2 film thickness on the interfacial layer (IL) evolution were studied when tetrakis(ethylmethylamino)hafnium and H2O based atomic layer deposition (ALD) was performed on InP substrates. While the self‐cleaning effect resulted in an IL‐free structure after formation of ~2 nm thick HfO2 at 200 °C and 250 °C, substantial IL growth occurred at 300 °C, probably due to simultaneous InP oxidation. Following further growth to ~8 nm at 300 °C, the IL was almost removed and, in particular, a significant In incorporation into the HfO2 film was observed, which was attributed to IL decomposition and subsequent out‐diffusion of the constituent elements. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
282.
Thick target 7Li(p,n) neutron spectra were measured using a 3He ion chamber in the proton energy range of 1.95 to 2.30 MeV. The fast neutron spectra were collected for various distances from the lithium target as well as for various neutron emission angles. By unfolding the 3He raw data with the iterative van Cittert algorithm, the neutron fluence spectra were obtained. The 3He measured neutron spectra were compared with both analytically computed and Monte Carlo simulated spectra to account for neutron scatterings in the lithium target assembly and in the experimental area. To verify the accuracy of the neutron dose computation, the fast neutron kerma was obtained for each neutron spectrum using the fluence to kerma conversion coefficients and was compared with the measured neutron dose using tissue-equivalent proportional counters. In the position dependence investigation at the 0° emission angle, the analytically computed neutron kerma overestimates the experimental kerma by a factor of two mainly due to neutron moderation. The corresponding neutron kerma from the 3He measured spectra were in agreement with the neutron doses measured using tissue-equivalent proportional counters within 20% for lower proton energies, but the discrepancy increased to ~50% for higher proton energies. In the angular distribution investigation, a notable discrepancy between measured and computed neutron spectra were observed due to the neutron scattering effects in the target assembly and experimental room. 相似文献
283.
Jhun JY Yoon BY Park MK Oh HJ Byun JK Lee SY Min JK Park SH Kim HY Cho ML 《Experimental & molecular medicine》2012,44(7):424-431
White fat cells secrete adipokines that induce inflammation and obesity has been reported to be characterized by high serum levels of inflammatory cytokines such as IL-6 and TNF-α. Rheumatoid arthritis (RA) is a prototype of inflammatory arthritis, but the relationship between RA and obesity is controversial. We made an obese inflammatory arthritis model: obese collagen-induced arthritis (CIA). C57BL/6 mice were fed a 60-kcal high fat diet (HFD) from the age of 4 weeks and they were immunized twice with type II collagen (CII). After immunization, the obese CIA mice showed higher arthritis index scores and histology scores and a more increased incidence of developing arthritis than did the lean CIA mice. After treatment with CII, mixed lymphocyte reaction also showed CII-specific response more intensely in the obese CIA mice than lean CIA. The anti-CII IgG and anti-CII IgG2a levels in the sera of the obese CIA mice were higher than those of the lean CIA mice. The number of Th17 cells was higher and the IL-17 mRNA expression of the splenocytes in the obese CIA mice was higher than that of the lean CIA mice. Obese CIA mice also showed high IL-17 expression on synovium in immunohistochemistry. Although obesity may not play a pathogenic role in initiating arthritis, it could play an important role in amplifying the inflammation of arthritis through the Th1/Th17 response. The obese CIA murine model will be an important tool when we investigate the effect of several therapeutic target molecules to treat RA. 相似文献
284.
J Byun J Shin S Kwon S Jang JK Kim 《Chemical communications (Cambridge, England)》2012,48(74):9278-9280
We report a novel approach for the fabrication of a photo-responsive surface with fast and reversibly switchable wettability between hydrophobicity and hydrophilicity induced by a photothermal effect. 相似文献
285.
We demonstrated enhanced surface plasmon resonance (SPR) detection by incorporating an indium tin oxide (ITO) layer on a thin gold film. Porous ITO layers were fabricated by e-beam evaporation and slanted deposition at room temperature and the ITO structure was optimized in terms of the surface roughness and the SPR curve characteristics. In sensing experiments, the results obtained by ethanol–water mixture test showed that SPR substrates with a porous ITO layer provided a notable sensitivity improvement compared to a conventional bare gold film, which is attributed to the nonlinear dispersion characteristic of surface plasmons. Our approach is intended to show the feasibility and extend the applicability of the porous ITO-mediated SPR biosensor to diverse biomolecular binding events. 相似文献
286.
Jae Hwan Kim Da Hyun Kim Seongin Jo Min Je Cho Ye Ryeong Cho Yong Joon Lee Sanguine Byun 《Experimental & molecular medicine》2022,54(1):1
The immune system comprises a complex group of processes that provide defense against diverse pathogens. These defenses can be divided into innate and adaptive immunity, in which specific immune components converge to limit infections. In addition to genetic factors, aging, lifestyle, and environmental factors can influence immune function, potentially affecting the susceptibility of the host to disease-causing agents. Chemical compounds in certain foods have been shown to regulate signal transduction and cell phenotypes, ultimately impacting pathophysiology. Research has shown that the consumption of specific functional foods can stimulate the activity of immune cells, providing protection against cancer, viruses, and bacteria. Here, we review a number of functional foods reported to strengthen immunity, including ginseng, mushrooms, chlorella, and probiotics (Lactobacillus plantarum). We also discuss the molecular mechanisms involved in regulating the activity of various types of immune cells. Identifying immune-enhancing functional foods and understanding their mechanisms of action will support new approaches to maintain proper health and combat immunological diseases.Subject terms: Health care, Pathogenesis 相似文献
287.
K. S. Kim C. S. Oh W. -H. Lee K. J. Lee G. M. Yang C. -H. Hong E. -K. Suh K. Y. Lim H. J. Lee D. J. Byun 《Journal of Crystal Growth》2000,210(4):505-510
We have grown undoped, Si- and Mg-doped GaN epilayers using metalorganic chemical vapor deposition. The grown samples have electron Hall mobilities (carrier concentrations) of 798 cm2/V s (7×1016 cm−3) for undoped GaN and 287 cm2/V s (2.2×1018 cm−3) for Si-doped GaN. Mg-doped GaN shows a high hole concentration of 8×1017 cm−3 and a low resistivity of 0.8 Ω cm. When compared with undoped GaN, Si and Mg dopings increase the threading dislocation density in GaN films by one order and two orders, respectively. Besides, it was observed that the Mg doping causes an additional biaxial compressive stress of 0.095 GPa compared with both undoped and Si-doped GaN layers, which is due to the incorporation of large amount of Mg atoms (4–5×1019 cm−3). 相似文献
288.
H.Y. Byun I.J. Chung Y.-S. Suh H.K. Shim D.Y. Kim C.Y. Kim 《Macromolecular Symposia》2003,192(1):151-160
A blend of a newly synthesized polyfluorene(PDHBF) and polyvinylcarbazole(PVK) exhibits a photoluminescence(PL) emission spectrum of PDHBF without an increase in the PL intensity on photoexcitation at 340 nm, the UV-visible absorption maximum of PVK, despite of a substantial spectrum overlap. However, the indirect photoexcitation of the blend suppresses the secondary emission of the PL with the maximum at 520 nm. The chromophores generating the secondary emission are formed when the chromophores are photoexcited above the critical energy level of an excited state. The chromophores formed by the energy transfer have energy lower than the critical energy and fail to form the excimers. A low temperature PL study of the blend in a cryogenic chamber proves that the energy transfer in the system takes place mainly between the excimers of PVK generated by the partially eclipsed dimeric states of two carbazole units and the fluorophores of PDHBF. 相似文献
289.
We obtain Calderón–Zygmund-type gradient estimates below the duality exponent of very weak solutions to p-Laplacian-type elliptic equations with non-divergence datum by providing an analytic approach without using the fractional maximal function of order 1 for the non-divergence datum. 相似文献
290.