全文获取类型
收费全文 | 100篇 |
免费 | 1篇 |
专业分类
化学 | 69篇 |
晶体学 | 1篇 |
数学 | 9篇 |
物理学 | 9篇 |
无线电 | 13篇 |
出版年
2023年 | 1篇 |
2022年 | 9篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 8篇 |
2012年 | 3篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 4篇 |
2008年 | 3篇 |
2007年 | 7篇 |
2006年 | 8篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 1篇 |
2002年 | 3篇 |
1999年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有101条查询结果,搜索用时 15 毫秒
81.
Khajuria RK Bhardwaj V Gupta RK Sharma P Somal P Mehta P Qazi GN 《Journal of chromatographic science》2007,45(8):519-523
This paper describes the development of a normal-phase liquid chromatograph-UV-diode array detection-positive ion atmospheric pressure chemical ionization-mass spectrometry method for the simultaneous identification and quantitation of cholesterol, androst-4-ene-3,17-dione (AD), and androsta-1,4-diene-3,17-dione (ADD) in fermentation broths. The compounds detected under positive ion atmospheric pressure chemical ionization on a mass spectrometer by selected ion monitoring are separated by normal-phase high-performance liquid chromatography. [M+H]+ ions are taken into consideration for quantitation of AD and ADD, and [M-H2O+H]+ ions are considered for quantitation of cholesterol. The compounds are analyzed on a Si60 silica (5 microm, 125 x 4-mm i.d.) Merck column using a 2:3 isocratic mixture of isopropyl alcohol and hexane. The calibration curves resulting from the reference compounds in the concentration range of 100-5000 pg on column exhibit a good linear correlation (r2 > or = 0.996). The method is validated by analyzing six replicates of broth samples fortified with three compounds, namely, cholesterol, AD, and ADD, at 0.050 and 0.5 microg/g levels. The mean recoveries for the fortifications range from 90% to 98% with relative standard deviations in the range of 3.36% to 9.78%. The method is developed to study the qualitative as well as quantitative conversion of cholesterol to AD and ADD by a microorganism identified as Nocardia sp. These studies helped the investigation of the reaction kinetics, which showed that the molar biotransformation of cholesterol into AD and ADD was 21%, even when the reaction was prolonged for 96 h. 相似文献
82.
Chenmala Karthika Agnieszka Najda Joanna Klepacka Mehrukh Zehravi Rokeya Akter Muhammad Furqan Akhtar Ammara Saleem Majed Al-Shaeri Banani Mondal Ghulam Md. Ashraf Priti Tagde Sarker Ramproshad Zubair Ahmad Farhat S. Khan Md. Habibur Rahman 《Molecules (Basel, Switzerland)》2022,27(14)
A brain tumor (BT) is a condition in which there is growth or uncontrolled development of the brain cells, which usually goes unrecognized or is diagnosed at the later stages. Since the mechanism behind BT is not clear, and the various physiological conditions are difficult to diagnose, the success rate of BT is not very high. This is the central issue faced during drug development and clinical trials with almost all types of neurodegenerative disorders. In the first part of this review, we focus on the concept of brain tumors, their barriers, and the types of delivery possible to target the brain cells. Although various treatment methods are available, they all have side effects or toxic effects. Hence, in the second part, a correlation was made between the use of resveratrol, a potent antioxidant, and its advantages for brain diseases. The relationship between brain disease and the blood–brain barrier, multi-drug resistance, and the use of nanomedicine for treating brain disorders is also mentioned. In short, a hypothetical concept is given with a background investigation into the use of combination therapy with resveratrol as an active ingredient, the possible drug delivery, and its formulation-based approach. 相似文献
83.
Soumav Nath Priti Roy Raki Mandal Rajat Roy Prof. PhD Alexander K. Buell Dr. PhD Neelanjana Sengupta Dr. PhD Pradip K. Tarafdar 《化学:亚洲杂志》2021,16(23):3931-3936
Amyloid fibril formation of proteins is of great concern in neurodegenerative disease and can be detrimental to the storage and stability of biologics. Recent evidence suggests that insulin fibril formation reduces the efficacy of type II diabetes management and may lead to several complications. To develop anti-amyloidogenic compounds of endogenous origin, we have utilized the hydrogen bond anchoring, π stacking ability of porphyrin, and investigated its role on the inhibition of insulin amyloid formation. We report that hydroxylation and metal removal from the heme moiety yields an excellent inhibitor of insulin fibril formation. Thioflavin T, tyrosine fluorescence, Circular Dichorism (CD) spectroscopy, Field emission scanning electron microscopy (FESEM) and molecular dynamics (MD) simulation studies suggest that hematoporphyrin (HP) having hydrogen bonding ability on both sides is a superior inhibitor compared to hemin and protoporphyrin (PP). Experiments with hen egg white lysozyme (HEWL) amyloid fibril formation also validated the efficacy of endogenous porphyrin based small molecules. Our results will help to decipher a general therapeutic strategy to counter amyloidogenesis. 相似文献
84.
85.
JPC – Journal of Planar Chromatography – Modern TLC - In the present study, a design-of-experiment (DoE) approach Was used to determine optimized mobile-phase compositions for the... 相似文献
86.
Environmental Monitoring System for Smart City Based on Secure Internet of Things (IoT) Architecture
Malche Timothy Maheshwary Priti Kumar Rakesh 《Wireless Personal Communications》2019,107(4):2143-2172
Wireless Personal Communications - With increasing population, urbanization, energy, transportation, and agricultural developments, pollution is degrading the environment with ever-increasing pace.... 相似文献
87.
Hemant Kumar Priti Priya Nena Singh Mukesh Kumar Binod Kumar Choudhary Lokendra Kumar Indu Shekhar Singh Nitish Kumar 《Applied biochemistry and biotechnology》2016,180(7):1345-1360
Euryale ferox Salisbury is an important aquatic food plant cultivated largely in eastern India. E. ferox is a monotypic genus, and breeding programmes have mostly relied on the variability present in the primary gene pool. Knowledge of the genetic structure of the population is limited, and there are very few reports available on the genetic diversity of E. ferox. In this study, comprehensive research on the genetic diversity of 16 germplasms of E. ferox was carried out using random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers. Out of 320 RAPD and 95 ISSR primers screened initially, 61 primers (40 RAPD and 21 ISSR) gave reproducible bands and were selected for further work. Amplification of the 40 RAPD primers gave 533 polymorphic bands with an average of 13.32 polymorphic bands per primer. The percentage of polymorphism ranged from 37.5 to 100, with an average of 88.3 %. The 21 ISSR primers produced 259 bands, of which 214 were polymorphic, with an average of 10.19 polymorphic bands per primer. The percentage of polymorphism using ISSR primers ranged from 50 to 100, with a mean of 82.6 %. Jaccard’s coefficient ranged from 0.45 to 0.69 (RAPD), 0.50 to 0.77 (ISSR) and 0.48 to 0.71 (RAPD and ISSR). Molecular characterization of different germplasms of E. ferox not only is essential for its conservation but also can be used in further breeding programmes. 相似文献
88.
Jolly M Sankalia Rajashree C Mashru Mayur G Sankalia Priti P Parikh Vijay B Sutariya 《Analytical sciences》2004,20(9):1321-1325
Two new specific, selective, simple and inexpensive spectroscopic methods for estimating a trace amount of chromium (Cr3+) from a multi-vitamin with multi-mineral pharmaceutical formulations were developed. The proposed methods are based on the conversion of Cr3+ to Cr6+ either by oxidation with a nitric acid-perchloric acid mixture (method I) or by fusion with an excess amount of sodium carbonate (method II), followed by the complexation of Cr6+ with 1,5-diphenylcarbazide (DPC) in a mineral acidic solution of pH 1.0 +/- 0.5. The pink-colored complex was estimated at 544 nm. Both methods were found to be linear in the range of 0.1 - 0.8 microg/ml with a limit of detection in the range of 0.0123 - 0.0157 microg/ml and a limit of quantitation in the range of 0.0419 - 0.0525 microg/ml. Method I was found to be suitable for estimating Cr3+ species in various formulations, like tablets, capsules and syrups, while method II was found to be suitable for tablets and capsules. Satisfactory recovery from spiked samples of standard Cr3+ suggests no interference of any excipients and diverse ions present in the formulations. The developed methods were compared with AAS by ANOVA, and no significant difference was observed. 相似文献
89.
An asymmetric synthesis of (S)-oxybutynin 1 is described using the Sharpless asymmetric dihydroxylation of α-cyclohexylstyrene as the key step. 相似文献
90.
Yu Lei Priti Mulchandani Wilfred Chen Joseph Wang Ashok Mulchandani 《Electroanalysis》2004,16(24):2030-2034
An amperometric microbial biosensor for highly sensitive and selective determination of p‐nitrophenol (PNP) is reported. The biosensor consisted of PNP‐degrader Arthrobacter sp. JS443 immobilized by entrapment in Nafion polymer deposited on the top of the carbon paste electrode transducer. The biosensor was based on the measurement of the oxidation current of the intermediates 4‐nitrocatechol and 1,2,4‐benzenetriol formed by the highly selective oxidation of PNP by Arthrobacter sp. The sensor signal and response time were optimized with applied potential of +0.4 V (vs. Ag/AgCl reference electrode) and 0.03 mg of cells and operating in pH 7.5, 50 mM citrate‐phosphate buffer at room temperature. When operated at optimized conditions, the Arthrobacter sp.‐based biosensor measured as low as 5 nM (0.7 ppb) of PNP. The biosensor demonstrated excellent selectivity with no interference from phenolic compounds such as 2‐nitrophenol, phenol and 3‐chlorophenol but was interfered by 3‐nitrophenol and 3‐methyl‐4‐nitrophenol. It had good precision and intra‐ and inter‐day reproducibility, accuracy and was stable up to 3 days when stored in buffer at 4 °C. When applied for measurement in water from Lake Elsinore, CA, the results obtained were in excellent agreement with the amounts determined spectrophotometrically. 相似文献