全文获取类型
收费全文 | 328篇 |
免费 | 62篇 |
国内免费 | 205篇 |
专业分类
化学 | 447篇 |
晶体学 | 10篇 |
力学 | 8篇 |
综合类 | 6篇 |
数学 | 3篇 |
物理学 | 121篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 7篇 |
2020年 | 15篇 |
2019年 | 18篇 |
2018年 | 10篇 |
2017年 | 19篇 |
2016年 | 33篇 |
2015年 | 22篇 |
2014年 | 26篇 |
2013年 | 36篇 |
2012年 | 43篇 |
2011年 | 38篇 |
2010年 | 34篇 |
2009年 | 36篇 |
2008年 | 36篇 |
2007年 | 43篇 |
2006年 | 25篇 |
2005年 | 23篇 |
2004年 | 20篇 |
2003年 | 11篇 |
2002年 | 20篇 |
2001年 | 12篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
排序方式: 共有595条查询结果,搜索用时 156 毫秒
61.
Gold nanoparticles (nano Au)/titanium dioxide (TiO2) hollow microsphere membranes were prepared on the carbon paste electrode (CPE) for enhancing the sensitivity of DNA hybridization
detection. The immobilization of nano Au and TiO2 microsphere was investigated with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The hybridization
events were monitored with EIS using [Fe(CN)6]3−/4− as indicator. The sequence-specific DNA of the 35S promoter from cauliflower mosaic virus (CaMV35S) gene was detected with
this DNA electrochemical sensor. The dynamic detection range was from 1.0×10−12 to 1.0×10−8 mol/L DNA and a detection limit of 2.3×10−13 mol/L could be obtained. The polymerase chain reaction (PCR) amplification of the terminator of nopaline synthase (NOS) gene
from the real sample of a kind of transgenic soybean was also satisfactorily detected.
Supported by the National Natural Science Foundation of China (Grant Nos. 20635020 and 20375020), Doctoral Foundation of the
Ministry of Education of China (Grant No. 20060426001) and Natural Science Foundation of Qingdao City (Grant No. 04-2-JZP-8) 相似文献
62.
Hasegawa T Iijima K Hirota K Nakajima T Makino K Terada H 《Colloids and surfaces. B, Biointerfaces》2008,63(2):209-216
A method for exact determination of phagocytic activity of alveolar macrophage (M) cells toward synthetic microspheres (MS) by optical microscopy was developed. We examined the effectiveness of the treatment of M samples with trypsin, acid or xylene to remove the polystyrene latex microspheres (PSL MS) attached to M cell membranes during their phagocytosis by M cells. We found that centrifugation, which was employed to collect M samples after incubation with MS, affected significantly the efficiency of the various treatments. Of the three treatments, xylene treatment without centrifugation was the most effective to determine the phagocytic activity of M cells, as xylene dissolved the PSL MS on the cell surface almost completely. This treatment was also effective in the case of poly(lactic-co-glycolic acid) MS (PLGA MS), which have been commonly used as an efficient vehicle for drug delivery system. 相似文献
63.
以聚乙二醇为模板剂制备MoS2空心微球 总被引:1,自引:0,他引:1
以聚乙二醇(PEG)为模板剂, 采用软模板法制备出MoS2空心微球, 并采用X射线衍射仪(XRD)、红外光谱仪(IR)和扫描电子显微镜(SEM)对产物进行表征. 结果表明, 所制备的MoS2为粒径约2-7 μm的空心微球, 但结晶程度较差, 需通过退火工艺进行改善; 聚乙二醇与MoS2发生了较为强烈的有机-无机杂化作用, 其浓度和分子量对产物形貌调控均有重要影响. 同时, 结合红外光谱分析, 对MoS2空心微球的形成机理进行了初步的探讨. 相似文献
64.
以甲基丙烯酸缩水甘油酯为单体(GMA)、乙二醇二甲基丙烯酸酯(EDMA)为交联剂,采用原子转移自由基聚合法(ATRP)制备了PGMA-EDMA大孔聚合物微球,采用傅里叶变换红外光谱、扫描电子显微镜及压汞法对PGMA-EDMA微球进行了表征.研究结果表明,原子转移自由基聚合法制备的PGMA-EDMA微球的孔径尺寸及比表面积均大于普通自由基聚合法(CFRP)制备的PGMA-EDMA;ATRP法制备的PGMAEDMA微球的颗粒尺寸(100~400 nm)明显小于CFRP法制备的PGMA-EDMA微球的颗粒尺寸(1000 nm).PGMA-EDMA(ATRP)的微球粒径尺寸分布优于PGMA-EDMA(CFRP).因此PGMA-EDMA(APRP)微球在快速蛋白分离纯化方面有潜在的应用前景. 相似文献
65.
ABSTRACTThis study investigates the optical resonance spectra of free-standing monolithic single crystal silicon microspheres immersed in various amorphous fluids, such as air, water, ethylene glycol, and 4-Cyano-4’-pentylbiphenyl nematic liquid crystal. For the various amorphous fluids, morphology-dependent resonances with quality factors on the order of 105 are observed at 1428 nm. The mode spacing is always on the order of 0.23 nm. The immersion in various amorphous fluids affects the spectral response of the silicon microsphere and heralds this technique for use in novel optofluidics applications. Even though the nematic liquid crystal is a highly birefringent, scattering, and high-index optical medium, morphology-dependent resonances with quality factors on the order of 105 are observed at 1300 nm in the elastic scattering spectra of the silicon microsphere, realizing a liquid-crystal-on-silicon geometry. The relative refractive index and the size parameter of the silicon microsphere are the parameters that affect the resonance structure. The more 4-Cyano-4’-pentylbiphenyl interacting with the silicon microsphere, the lower the quality factor of the resonances is. The more 4-Cyano-4’-pentylbiphenyl is interacting with the silicon microsphere, the lower the mode spacing Δλ of the resonances is. The silicon microspheres wetted with nematic liquid crystal can be used for optically addressed liquid-crystal-on-silicon displays, light valve applications, or reconfigurable optical networks. 相似文献
66.
在静态法合成聚对苯二胺纳米片的基础上,经一步水热将铜微球均匀锚定于其上,成功合成了具有良好导电性、大比表面积、大孔径和孔容的铜/聚对苯二胺(Cu/Pp PD)复合物,其独特的结构有利于电子的转移、活性位点的充分利用以及反应物、电解质等的输运。复合物对葡萄糖氧化表现出很高的电催化活性,在最优测试条件下,所构建的葡萄糖无酶传感器响应时间短(达到稳定电流的95%所需时间小于3 s)、线性范围宽(0.003~6.44 mmol/L)、灵敏度高(929μA·mmol-1·L·cm-2)、检出限低(4.48×10-7mol/L)、重现性和选择性好,对血清样品进行检测,回收率为99.5%~101.1%。所制备Cu/Pp PD复合物能实现对葡萄糖的简单、快速、灵敏、准确无酶检测,在临床医学上糖尿病人的早期诊断和治疗监测领域具有很好的应用前景。 相似文献
67.
A facile method to fabricate molecularly imprinted polymers (MIPs) on glass microspheres in a column was developed. The column
was prepacked with glass microspheres, and then the prepolymerization mixture was injected into the interstitial volume of
the column. The polymerization took place in situ and the column could be directly used for high-performance liquid chromatography
after the template had been removed. The template consumption was reduced greatly because the prepolymerization mixture just
filled the interstitial volume between the glass microspheres in the column. The MIPs obtained exhibited better kinetic properties,
higher efficiency, and low back pressure of the column. Emodin imprinted polymers were prepared by this method and were used
for solid-phase extraction. 相似文献
68.
LINEAR AND NONLINEAR SEMICLASSICAL THEORY OF WHISPERING-GALLERY-MODE MICROSPHERE LASER 总被引:1,自引:0,他引:1 下载免费PDF全文
A complete whispering-gallery-mode microsphere laser theory is developed, which combines usual laser semiclassical theory with Lorenz-Mie theory. The linear and nonlinear problems of the microsphere lasing are dealt with in the universal mode picture. The threshold condition, average amplitude of the steady state and frequency effect are obtained. A comparison between the theory and experiments is also made. 相似文献
69.
70.