全文获取类型
收费全文 | 908篇 |
免费 | 29篇 |
国内免费 | 8篇 |
专业分类
化学 | 613篇 |
晶体学 | 20篇 |
力学 | 29篇 |
综合类 | 1篇 |
数学 | 41篇 |
物理学 | 241篇 |
出版年
2024年 | 3篇 |
2023年 | 12篇 |
2022年 | 65篇 |
2021年 | 52篇 |
2020年 | 28篇 |
2019年 | 38篇 |
2018年 | 21篇 |
2017年 | 19篇 |
2016年 | 34篇 |
2015年 | 24篇 |
2014年 | 35篇 |
2013年 | 62篇 |
2012年 | 72篇 |
2011年 | 72篇 |
2010年 | 36篇 |
2009年 | 39篇 |
2008年 | 37篇 |
2007年 | 41篇 |
2006年 | 33篇 |
2005年 | 30篇 |
2004年 | 30篇 |
2003年 | 26篇 |
2002年 | 15篇 |
2001年 | 6篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1976年 | 4篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有945条查询结果,搜索用时 15 毫秒
91.
Manirul Islam Paramita Mondal Anupam Singha Roy Kazi Tuhina 《Transition Metal Chemistry》2010,35(4):427-435
A poly(3,6-dibenzaldimino N-vinyl carbazole) Pd(II) complex has been synthesized and characterized by physicochemical and spectroscopic techniques. The complex was found to be highly active toward hydrogenation reactions of various organic substrates under atmospheric pressure at ambient temperature. A tentative reaction mechanism is proposed on the basis of kinetic studies and isolation of reactive intermediates. The catalyst shows good conversion rates, thermal stability and recyclability. 相似文献
92.
Measurement of mixed radon and thoron daughter concentrations using alpha and beta activities filtered from air 总被引:1,自引:0,他引:1
This paper presents a detailed study of integral four- and five-count filter methods for the measurement of mixed radon and thoron daughter concentrations in air. The four-count method utilizes beta activity measurement while the five-count method is based on alpha activity measurement with plastic track detectors. A good correlation between the two independent detection techniques has been observed. An adequate theoretical framework is provided by interpreting the observed data. 相似文献
93.
Dually Electroactive Disulfide‐Confined Aryldiazonium Salt Used as a Linker Molecule for Preparing Immunosensor Platforms 下载免费PDF全文
Md. Mohibul Islam Khan Mithrabinda K. Poduval Tae‐Hyun Kim Kyuwon Kim 《Electroanalysis》2015,27(8):1952-1959
A new electroactive disulfide‐confined aryl diazonium (DSAD) salt was synthesized and used as a linker for biomolecules immobilization to prepare two kinds of immunoassay platforms. DSAD was electrodeposited on ITO electrode surfaces by cyclic voltammetry. Disulfide group of DSAD attached on the surfaces were electrochemically oxidized into thiosulfinate or thiosulfonate groups. For the first work, a detection of rabbit antigen was performed on ITO microelectrodes array by spatially‐selective approach. In the second work, DSAD was deposited on electrochemically reduced graphene oxide‐modified ITO surfaces, which were used as a platform for electrochemical sandwich immunoassay for detecting mouse antigen. 相似文献
94.
Noorhidayah Ishak Mohd Noor Ahmad Azalina Mohamed Nasir Siti Fatimah Kamaruddin A. K. M. Shafiqul Islam Marinah Mohd Ariffin 《Polymer Science Series A》2017,59(5):649-659
Molecular imprinting is an approach to synthesize receptors with specific molecular recognition properties. A computational method was carried out to study interaction between template and monomer in prepolymerization mixture. The functional monomer and template complexes were optimized, at the minimum energy confirmation using Austin Model 1 semi empirical method within Restricted Hartree Fock formalism. The theoretical results showed that allylthiourea (functional monomer) has the largest interaction energy towards template (sodium nitrate) with the mole ratio of 4 : 1; functional monomer : template. The resulting polymers were characterized using Fourier Transform infrared spectroscopy, thermogravimetry analysis and field emission scanning electron microscopy. Rebinding experiments were carried out to evaluate binding capacity of the polymer. The adsorption data of ion imprinted polymer (IIP) were fitted with Langmuir-Freundlich isotherm model. Pseudo-second order kinetic model was used to describe the kinetic adsorption behavior of IIP. The experimental binding result showed good agreement with theoretical computation and the IIP was further used for nitrate ion detection. The results of membrane optimization indicated that the sensor, which composed of 30% polyvinylchloride, 60% nitrophenyl octyl ether as a plasticizer, 2% sodium tetraphenyl borate, and 10% IIP as ionophore exhibited an almost Nernstian slope with the limit of detection 3.9 × 10-6 M. The fabricated sensor had shown good potential in nitrate detection with wide linear range, low limit of detection and found to have good selectivity towards nitrate ion over other anion. 相似文献
95.
96.
97.
We generated a series of new polymer-bound peroxo complexes of vanadium(V) and molybdenum(VI) of the type [VO(O(2))(2)(sulfonate)]-PSS [PSS = poly(sodium 4-styrene sulfonate)] (PV(3)), [V(2)O(2)(O(2))(4)(carboxylate)VO(O(2))(2)(sulfonate)]-PSSM [PSSM = poly(sodium styrene sulfonate-co-maleate)] (PV(4)), [Mo(2)O(2)(O(2))(4)(carboxylate)]-PA [PA = poly(sodium acrylate)] (PMo(1)), [MoO(O(2))(2)(carboxylate)]-PMA [PMA = poly(sodium methacrylate)] (PMo(2)), and [MoO(O(2))(2)(amide)]-PAm [PAm = poly(acrylamide)] (PMo(3)) by reacting V(2)O(5) (for PV(3) and PV(4)) or H(2)MoO(4) (for PMo(1), PMo(2), and PMo(3)) with H(2)O(2) and the respective water-soluble macromolecular ligand at pH 5-6. The compounds were characterized by elemental analysis (CHN and energy-dispersive X-ray spectroscopy), spectral studies (UV-vis, IR, (13)C NMR, (51)V NMR, and (95) Mo NMR), thermal (TGA) as well as scanning electron micrographs (SEM), and EDX analysis. It has been demonstrated that compounds retain their structural integrity in solutions of a wide range of pH values and are approximately 100 times weaker as substrate to the enzyme catalase relative to H(2)O(2), its natural substrate. The effect of the title compounds, along with previously reported compounds [V(2)O(2)(O(2))(4)(carboxylate)]-PA (PV(1)) and [VO(O(2))(2)(carboxylate)]-PMA (PV(2)) on rabbit intestine alkaline phosphatase (ALP) has been investigated and compared with the effect induced by the free diperoxometallates viz. Na[VO(O(2))(2)(H(2)O)] (DPV), [MoO(O(2))(2)(glycine)(H(2)O)] (DMo(1)), and [MoO(O(2))(2)(asparagine)(H(2)O)] (DMo(2)). It has been observed that although all the compounds tested are potent inhibitors of the enzyme, the polymer-bound and neat complexes act via distinct mechanisms. Each of the macromolecular compounds is a classical noncompetitive inhibitor of ALP. In contrast, the action of neat pV and heteroligand pMo compounds on the enzyme function is consistent with a mixed type of inhibition. 相似文献
98.
Heteroaromatic oligomer 5,7,12,14-tetrachloro-6,13-diazapentacene (TCDAP) was characterized and assessed as n-channel material in field-effect transistor applications. A single-crystal transistor based on TCDAP as the channel material exhibits a very high electron mobility of 3.39 cm(2) V(-1) s(-1) and an on/off ratio of ~1.08 × 10(4) respectively. 相似文献
99.
Abdulla-Al-Mamun M Kusumoto Y Zannat T Islam MS 《Physical chemistry chemical physics : PCCP》2011,13(47):21026-21034
The photocatalytic and plasmonic photothermal cancer cell-killing activity of the metallic Au-capped TiO(2) (Au@TiO(2)) composite colloidal nanopellets has been investigated on HeLa cells under UV-visible (350-600 nm) light irradiation. The Au@TiO(2) composite nanopellets with the uniform Au-capped TiO(2) structure were successfully synthesized by simple reduction of HAuCl(4) on the surface of TiO(2) nanoparticles. The morphological structure and surface properties of Au@TiO(2) were characterized by using UV-visible absorption spectroscopy, TEM, SEM, XPS, EDX and XRD analyses. The formation of hydroxyl radicals (˙OH) was confirmed by photoluminescence (PL) spectra. The photocatalytic and photothermal cell-killing activity of the Au@TiO(2) nanopellets was found to vary with the molar ratio of Au to TiO(2). The direct involvement of the metal particles in mediating the electron transfer from the photoexcited TiO(2) under the band gap excitation is considered to carry out the efficient photocatalytic reaction on the cells. The plasmonic absorption spectra of Au@TiO(2) suspensions were also measured for the evaluation of photothermal cell killing. The charge separation, the interfacial charge-transfer and photothermal activity promoted the photocatalytic-photothermal cancer-cell killing more than TiO(2) alone. The cytotoxic effect of Au@TiO(2) nanopellets with low concentration of gold (TiO(2) : Au molar ratio > 1 : 1) was found to be 100%, whereas that of the commercial TiO(2) (P25) was ca. 50%. The comparative study of the cell viability using Au alone and TiO(2) alone revealed that the synergistic effect of photocatalytic hydroxyl radical formation and Au-plasmonic photothermal heat generation plays a vital role in the cancer cell killing. A plausible mechanism was also proposed for photocatalytic cancer cell killing based on the obtained results. 相似文献
100.
Matthew Monari Ombaba V. J. Logeeswaran M. Saif Islam 《Applied Physics A: Materials Science & Processing》2013,111(1):251-259
In this paper we report a novel application of electrically conductive film (ECF) of Ag sub-micron particles that includes both isotropic and anisotropic film technologies in providing simultaneous electrical contact and mechanical anchor between fracture transfer-printed (1-D) single crystal semiconductor micro- and nano-pillars and a carrier substrate. We assembled silver sub-micron particles (AgSP) monolayers with varying particle diameters and investigated their optical and electrical characteristics prior to their incorporation into thermoplastic polymers. It was found that transfer-printing of the Si micropillar arrays, into electrically conductive thermoplastic receiver substrates, made of films of AgSP/PMMA blends atop metallic substrates could be effectively achieved to yield electrically interfaced 1-D Si micropillar arrays with retention of their orientation and integrity according to the SEM images. The carrier substrate can potentially be reused to generate additional Si micropillar arrays that can be similarly harvested. 相似文献