全文获取类型
收费全文 | 160篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 108篇 |
晶体学 | 5篇 |
力学 | 4篇 |
数学 | 2篇 |
物理学 | 45篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2018年 | 1篇 |
2017年 | 5篇 |
2015年 | 1篇 |
2014年 | 5篇 |
2013年 | 14篇 |
2012年 | 5篇 |
2011年 | 5篇 |
2010年 | 3篇 |
2009年 | 9篇 |
2008年 | 2篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 8篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有164条查询结果,搜索用时 15 毫秒
141.
Salwinder Singh Dhaliwal Vivek Sharma Arvind Kumar Shukla Vibha Verma Sanjib Kumar Behera Prabhjodh Singh Sandhu Kamaljit Kaur Ahmed Gaber Yusuf S. Althobaiti Abdelhadi A. Abdelhadi Akbar Hossain 《Molecules (Basel, Switzerland)》2021,26(21)
To achieve the nutritional target of human food, boron (B) has been described as an essential mineral in determining seed and theoretical oil yield of Sesamum indicum L. The research to increase its cultivation is garnering attention due to its high oil content, quality and its utilization for various purposes, which include human nutrition as well as its use in the food industry. For this, a two-year field experiment was performed at PAU, Punjab, India to determine the effect of different concentrations of foliar-applied B (20, 30 and 40 mg L−1) and different growth stages of crop, i.e., we measured the effects on agroeconomic indicators and certain quality parameters of sesame using different concentrations of B applied at the flowering and capsule formation stages as compared to using water spray and untreated plants. Water spray did not significantly affect the studied parameters. However, B application significantly increased the yield, uptake, antioxidant activity (AOA) and theoretical oil content (TOC) compared to those of untreated plants. The maximum increase in seed yield (26.75%), B seed and stover uptake (64.08% and 69.25%, respectively) as well as highest AOA (69.41%) and benefit to cost ratio (B:C ratio 2.63) was recorded when B was applied at 30 mg L−1 at the flowering and capsule formation stages. However, the maximum sesame yield and B uptake were recorded when B was applied at a rate of 30 mg L−1. A significant increase in TOC was also recorded with a B application rate of 30 mg L−1. For efficiency indices, the higher values of boron agronomic efficiency (BAE) and boron crop recovery efficiency (BCRE) were recorded when B was applied at 20 mg L−1 (5.25 and 30.56, respectively) and 30 mg L−1 (4.96 and 26.11, respectively) at the flowering and capsule formation stages. In conclusion, application of B @ 30 mg L−1 at the flowering and capsule formation stages seemed a viable technique to enhance yield, B uptake and economic returns of sesame. 相似文献
142.
An experimental study was conducted to investigate fluid temperature fields inside a flat-plate solar collector tube. The results show the highest fluid temperature at the upper end of the tube which decreased gradually to the lowest value at the bottom end of the tube, whereas, the temperature field in the horizontal plane is symmetric about the centerline. The vertical temperature gradients vary with the axial distance. The local fluid temperature increased nonlinearly along the collector length and its magnitude decreased with an increase in the Reynolds number. The local Rayleigh number increased with the axial distance and at a given location, its magnitude increased with a decrease in the Reynolds number, whereas, the local Nusselt number trends in flat-plate collector tube are in general similar to that in the conventional laminar channel flows. The local fluid temperature increased with an increase in the incident heat flux at a given collector orientation but decreased for the inclined collectors. The results show that over the given Reynolds number range, the fluid in a flat-plate collector tube is stably stratified over most of the fluid cross-sectional domain and the convective currents are suppressed and restricted to a thin layer adjacent to the lower tube wall. The results from the present study provide the physical explanation for the heat transfer enhancement by insert devices. That is, the insert devices disrupt the stably stratified layer and induce mixing which enhances the heat transfer. 相似文献
143.
Pil Ju Ko Ryousuke Ishikawa Tsukasa Takamura Honglae Sohn Adarsh Sandhu 《Journal of Non》2012,358(17):2327-2330
Porous silicon (PSi) shows tremendous potential for applications including optical devices and biochemical biosensors due to the large surface area and convenience of surface functionalization of pores. Recently, variations of the Fabry–Pérot fringes shift with the refractive index of the material filling the pores of PSi have been used for real time monitoring of biorecognition processes, where the optical shift is determined by the magnitude of the optical thickness (2nL) by fast Fourier transform (FFT). The development of biosensing systems using functionalized superparamagnetic beads (SPBs) or ‘magnetic labels’ is expected to enable a fast, one-step immunoassay protocol. However, magnetic labels are difficult to infiltrate into small nanopores in silicon due to blocking effects such as surface tension, wettability, and stomatal morphology. Here, we investigated the optimal fabrication parameters of PSi with large pores into which magnetic labels easily infiltrate, and confirmed the penetration of SPBs by the changes in the optical thickness 2nL by reflectivity measurements. Finally, we show the potential for real-time point of care diagnostic system by utilizing our method. 相似文献
144.
Nishio K Masaike Y Ikeda M Narimatsu H Gokon N Tsubouchi S Hatakeyama M Sakamoto S Hanyu N Sandhu A Kawaguchi H Abe M Handa H 《Colloids and surfaces. B, Biointerfaces》2008,64(2):162-169
We developed novel magnetic nano-carriers around 180 nm in diameter for affinity purification. Prepared magnetic nano-carriers possessed uniform core/shell/shell nano-structure composed of 40 nm magnetite particles/poly(styrene-co-glycidyl methacrylate (GMA))/polyGMA, which was constructed by admicellar polymerization. By utilizing relatively large 40 nm magnetite particles with large magnetization, the magnetic nano-carriers could show good response to permanent magnet. Thanks to uniform polymer shell with high physical/chemical stability, the magnetic nano-carriers could disperse in a wide range of organic solvent without disruption of core/shell structure and could immobilize various kinds of drugs. We examined affinity purification using our prepared magnetic nano-carriers with anti-cancer agent methotrexate (MTX) as ligand. Our magnetic nano-carriers showed higher performance compared to commercially available magnetic beads in terms of purification efficiency of target including extent of non-specific binding protein. 相似文献
145.
Venugopal N McCurdy B Al Mehairi S Alamri A Sandhu GS Sivalingam S Drachenberg D Ryner L 《Magnetic resonance imaging》2012,30(2):195-204
Visualization of short echo time (TE) metabolites in prostate magnetic resonance spectroscopic imaging is difficult due to lipid contamination and pulse timing constraints. In this work, we present a modified pulse sequence to permit short echo time (TE=40ms) acquisitions with reduced lipid contamination for the detection of short TE metabolites. The modified pulse sequence employs the conformal voxel MRS (CV-MRS) technique, which automatically optimizes the placement of spatial saturation planes to adapt the excitation volume to the shape of the prostate, thus reducing lipid contamination in prostate magnetic resonance spectroscopic imaging (MRSI). Metabolites were measured and assessed using a modified version of LCModel for analysis of in vivo prostate spectra. We demonstrate the feasibility of acquiring high quality spectra at short TEs, and show the measurement of short TE metabolites, myo-inositol, scyllo-inositol, taurine and glutamine/glutamate for both single and multi-voxel acquisitions. In single voxels experiments, the reduction in TE resulted in 57% improvement in the signal-to-noise ratio (SNR). Additional 3D MRSI experiments comparing short (TE=40 ms), and long (TE=130 ms) TE acquisitions revealed a 35% improvement in the number of adequately fitted metabolite peaks (775 voxels over all subjects). This resulted in a 42 ± 24% relative improvement in the number of voxels with detectable citrate that were well-fitted using LCmodel. In this study, we demonstrate that high quality prostate spectra can be obtained by reducing the TE to 40 ms to detect short T2 metabolites, while maintaining positive signal intensity of the spin-coupled citrate multiplet and managing lipid suppression. 相似文献
146.
147.
H.C. Bryant A.A. Carter M. Coupland E. Eisenhandler W.R. Gibson P.I.P. Kalmus T.W. Pritchard H. Sandhu S.J. Watts G.T.J. Arnison A. Astbury J.K. Davies G.H. Grayer D. Hill A.W. Robertson T.P. Shah C. Sutton 《Nuclear Physics B》1980,168(2):207-221
The polarization parameter has been measured for K?p elastic scattering at nine incident beam momenta between 0.955 and 1.272 GeV/c covering the c.m. angular range . Experimental results and coefficients of Legendre polynomial fits to the data are presented and compared with other measurements and a partial-wave analysis. 相似文献
148.
C. G. Morgan Y. P. Yianni S. S. Sandhu A. C. Mitchell 《Photochemistry and photobiology》1995,62(1):24-29
Abstract—
A photochromic phospholipid, 1,2-bis[4-(4- n -butylphenylazo)phenylbutyroyl]phosphatidyl-choline (Bis-Azo PC) has been incorporated into liposomes of gel- and liquid-crystalline-phase phospholipids. Liposomes of gel-phase phospholipid are stable in the presence of the trans photostationary state Bis-Az.o PC and can encapsulate fluorescent marker dye. On photoisomerization to the cis photostationary state, trapped marker is rapidly released. Liposomes containing Bis-Azo PC can rapidly fuse together after UV isomerization, this process continuing in the dark. Exposure to white light causes reversion of Bis-Azo PC to the trans form and halts dye leakage and vesicle fusion. Both unilamellar and multilamellar liposomes are able to fuse together on UV exposure. On UV photolysis, liposomes containing Bis-Azo PC do not fuse with a large excess of unlabeled liposomes, but transfer of Bis-Azo PC can be demonstrated spectrophotometrically. Vesicles of pure gel-phase lipid containing trapped marker dye but initially no Bis-Azo PC become leaky as a result of this lipid transfer. Liposomes composed of liquid-crystalline-phase phosphatidylcholine-containing Bis-Azo PC neither leak trapped marker nor fuse together on photolysis, nor do liquid-crystalline-phase liposomes fuse with gel-phase liposomes under these conditions. These results are discussed together with some possible applications of liposome photodestabilization. 相似文献
A photochromic phospholipid, 1,2-bis[4-(4- n -butylphenylazo)phenylbutyroyl]phosphatidyl-choline (Bis-Azo PC) has been incorporated into liposomes of gel- and liquid-crystalline-phase phospholipids. Liposomes of gel-phase phospholipid are stable in the presence of the trans photostationary state Bis-Az.o PC and can encapsulate fluorescent marker dye. On photoisomerization to the cis photostationary state, trapped marker is rapidly released. Liposomes containing Bis-Azo PC can rapidly fuse together after UV isomerization, this process continuing in the dark. Exposure to white light causes reversion of Bis-Azo PC to the trans form and halts dye leakage and vesicle fusion. Both unilamellar and multilamellar liposomes are able to fuse together on UV exposure. On UV photolysis, liposomes containing Bis-Azo PC do not fuse with a large excess of unlabeled liposomes, but transfer of Bis-Azo PC can be demonstrated spectrophotometrically. Vesicles of pure gel-phase lipid containing trapped marker dye but initially no Bis-Azo PC become leaky as a result of this lipid transfer. Liposomes composed of liquid-crystalline-phase phosphatidylcholine-containing Bis-Azo PC neither leak trapped marker nor fuse together on photolysis, nor do liquid-crystalline-phase liposomes fuse with gel-phase liposomes under these conditions. These results are discussed together with some possible applications of liposome photodestabilization. 相似文献
149.
I. Safarik V. Sandhu E. M. Lown O. P. Strausz T. N. Bell 《Research on Chemical Intermediates》1990,14(2):105-131
It is only since 1985 that the absolute rate constanss have been measured for some reactions of divalent silylene species.
In this article the absolute rate constant data reported to date for the reactions of SiH2, SiMe2, SiMePh, SiHCl, SiCl2, SiF2 and SiBr2 are reviewed and, where possible, mechanistic pathways discussed. The reactivity of silylenes is, in general, much higher
than had previously been estimated on the basis of relative rate studies. 相似文献
150.
S. S. Sandhu J. N. Kumaria Prof. Ranjit S. Sandhu 《Monatshefte für Chemie / Chemical Monthly》1977,108(5):1105-1112
The stability constants of the complexes of 3-hydroxynaphthalene-2-carboxylic acid with some lanthanides have been obtained potentiometrically in aqueous dioxane (50%,V/V) at three temperatures and keeping the ionic strength at 0.1M (KNO3), usingIrving-Rossotti titration technique. The values of overall changes in G°, H°, and S° have also been evaluated. 相似文献