全文获取类型
收费全文 | 129篇 |
免费 | 0篇 |
专业分类
化学 | 71篇 |
晶体学 | 3篇 |
力学 | 1篇 |
数学 | 11篇 |
物理学 | 43篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 6篇 |
2012年 | 8篇 |
2011年 | 9篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 6篇 |
2007年 | 5篇 |
2006年 | 6篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有129条查询结果,搜索用时 62 毫秒
121.
We report temperature dependence of FMR linewidths (Γ) for a set of amorphous FeyNi80?yP14B6 alloys. The linewidths show maxima as a function of T. However, the temperatures (Tm) corresponding to the maxima not only differ from the low field freezing temperatures reported earlier but also depend on microwave frequency. We contend that the Tm ′s should not be used to identify the zero-field ferromagnetic-spin glass transition line. 相似文献
122.
123.
S. M. Bhagat 《Applied magnetic resonance》1995,8(1):45-55
We review results on the low-field microwave magnetoabsorption (LFMMA) in granular samples of YBCO and BSCCO. First, we show that the virgin response (increase in absorption on first application ofH) obeys a universal form (ΔP/α)=(1+H 0/H)?1. Interpreting this in conjunction with de magnetization isotherms on the same samples, we demonstrate that the data support a model in which the LFMMA arises from field dependent reduction in the critical currents of the weak links in the sample surface. Next, we present examples of the variety of hysteresis loops obtained on subsequent field cycling and interpret them in terms of the universal form provided thatH is replaced by an effective valueH eff. Attempts are made to delineate the various terms appearing inH eff. 相似文献
124.
Bhagat Singh 《Czechoslovak Mathematical Journal》2000,50(1):15-24
Necessary and sufficient conditions have been found to force all solutions of the equation
to behave in peculiar ways. These results are then extended to the elliptic equation
where is the Laplace operator and p 3 is an integer. 相似文献
125.
G.V. Kurlyandskaya Jessica Cunanan S.M. Bhagat S.E. Jacobo 《Journal of Physics and Chemistry of Solids》2007,68(8):1527-1532
Three kinds of nanoscale powders containing Fe3O4 nanoparticles (NPs) have been studied by ferromagnetic resonance (FMR): (i) Fe3O4 NPs grown and then covered with polyaniline (PANI), (ii) unclad Fe3O4 NPs, and (iii) Fe3O4 NPs grown “in situ” with the PANI. In every case, there is no low field microwave absorption, rather a single FMR line is observed. However, the half-power widths are of order of 1 kOe presumably due to a distribution of internal fields. For type I particles with a low concentration (below 40%) of Fe3O4, the observed resonance fields (Hr) are close to those expected for spheres with negligible magnetocrystalline anisotropy. For all other cases, Hr values are significantly lower. Such shortfalls can be roughly understood by invoking dipolar interactions between the grains, stresses frozen in grains during manufacture (method III), as well as anisotropy fields when the specimens are prepared in an aligning field. 相似文献
126.
In this paper, we introduce a new and simple method of patterning polydimethylsiloxane (PDMS) directly using benzophenone as a photoinitiator. The photodefinable PDMS mixture (photoPDMS) is positive-acting and only sensitive to light below 365 nm, permitting processing under normal ambient light. Features of the order of 100 microm, which are sufficiently small for most microfluidic applications, were successfully fabricated using this novel process. A parametric study of process parameters was performed to optimize the fabrication. As a demonstration, microfluidic channels of varying dimensions were successfully fabricated using this process and experimentally characterized using fluorescence microscopy. To further demonstrate photoPDMS potential, thin (<30 microm) free-standing films with through patterns were fabricated and successfully used as shadow masks. The photoPDMS process completely eliminates the need for a master, permits processing under normal ambient light conditions, and makes fabrication fast and simple. This process for rapid prototyping of low-cost, disposable LOCs can be accomplished without cleanroom facilities and thus can be employed for a wide range of applications. 相似文献
127.
Membranes for preconcentration of molecular iodine were developed by two different routes: (i) UV-grafting of 1-vinyl-2-pyrrolidone in the pores of microporous poly(propylene) host membrane (grafted membrane), and (ii) physical immobilization of preformed poly(vinylpyrrolidone) (PVP) in a plasticized cellulose triacetate matrix to form the polymer inclusion membrane (PVP-PIM). The UV-grafted PVP-membrane was found to be hydrophilic (water uptake capacity = 166 wt.%), while the PVP-PIM was found to be highly hydrophobic (≈2 wt.%). PVP-PIM was found to uptake only I2 from aqueous sample whereas I2 and I3− were sorbed in the grafted membrane. This selectivity of PVP-PIM towards I2 was attributed to its hydrophobicity that allows only neutral I2 to interact with PVP in the membrane matrix. Thus, the selective preconcentration and quantitative determination of I2 in aqueous sample was carried out using PVP-PIM. As PVP-PIM was optically transparent, the characteristic absorbance of PVP–I2 complex (λmax = 361 nm) could be used for quantitative determination of I2 in the membrane. The instrumental neutron activation analysis (INAA) of the I2-loaded PIM samples indicated that 82% could be sorbed into the PIM samples from the solution within 10 min of equilibration time. This membrane was applied to I2 determinations in the samples of 131I radiotracer. The concentration level of iodine species in these samples were in sub-ppb level. Therefore, these samples were ideal for testing the preconcentration efficiency of the membrane towards I2 by monitoring the radioactivity of 131I. The amounts of I2 in the aqueous samples were standardized by conventional solvent extraction of I2 with the chloroform for validating the preconcentration efficiency of PVP-PIM. The detection limit of I2 in aqueous samples by INAA hyphenated with PVP-PIM was found to be 0.3 ppb for a sample size of 25 mL. 相似文献
128.
Stuti Bhagat Simona Tyagi Sanjay Singh 《Particle & Particle Systems Characterization》2023,40(11):2300079
The therapeutic success of nanomedicines requires nanomaterials to either adhere to the surface or internalize within the cytoplasm. The endocytosis phenomenon is controlled by the nanomaterial's shape, size, composition, charge, and capping molecules. The membrane potential-based non-specific internalization of therapeutic nanomedicines offers limited benefits than receptor-based specific delivery. Glut receptor-based internalization of glucose molecules is a well-known process in cancerous cells, which is one of the most exploited strategies to target cancer cells using nanoparticles. However, the internalization process of other structurally similar monosaccharides (D-Galactose, Mannose, and D-Fructose) conjugated nanoparticles remains to be unexplored. Herein, D-Glucose, D-Galactose, Mannose, and D-Fructose-coated AuNPs and AgNPs have been synthesized and studied the role of Glut receptors in their internalization in liver cancer cells, and compared them with non-cancerous cells. Results revealed that almost all monosaccharide-coated NPs exhibited high uptake in liver cancer cells than non-cancerous cells. Glut-1 receptor is observed to play a key role in the uptake and inhibition of Glut-1 receptors by genistein lead to a significant decrease in nanoparticle uptake. In conclusion, monosaccharide-conjugated nanoparticles can be used to direct the selective internalization of AuNPs and AgNPs in hepatic cancer cells to realize therapeutic and imaging applications. 相似文献
129.
Dr. Chenikkayala Siva Sankara Dr. Shweta Bhagat Dr. Ajeet Chandra Prof. Dr. Irishi N. N. Namboothiri 《European journal of organic chemistry》2023,26(15):e202300069
An enantioselective desymmetrization of curcumins with 3-olefinic oxindoles involving a cascade double-Michael addition strategy provides direct access to spirocyclohexanone-oxindoles with complete regio- and diastereoselectivities and excellent enantioselectivities, besides good to excellent yields. The products possess three contiguous chiral centers and multiple reactive functionalities. The observed selectivities were rationalized by transitions state energy calculations at B3LYP//6-31g(d) level of DFT. 相似文献