全文获取类型
收费全文 | 172篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
化学 | 99篇 |
晶体学 | 7篇 |
力学 | 4篇 |
数学 | 25篇 |
物理学 | 40篇 |
出版年
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 9篇 |
2014年 | 12篇 |
2013年 | 8篇 |
2012年 | 17篇 |
2011年 | 10篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 11篇 |
2007年 | 15篇 |
2006年 | 11篇 |
2005年 | 11篇 |
2004年 | 12篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
排序方式: 共有175条查询结果,搜索用时 125 毫秒
41.
Divya B. Tripathy Anuradha Mishra James Clark Thomas Farmer 《Comptes Rendus Chimie》2018,21(2):112-130
Surfactant use throughout mankind is extensive, from their initial applications as detergents extending to use in medicine, lubricant, cosmetics and even enhanced oil recovery. However, the image of surfactant use has in the past been tarnished by issues with low biodegradability and their synthesis from nonsustainable resources. Amino acid–based surfactants are a class of surfactants derived from a hydrophobe source coupled with simple amino acids, mixed amino acids from synthesis or from protein hydrolysates, and as such can be derived solely from renewable resources. There are several pathways for their synthesis and this allows for extensive structural diversity in this class of surfactants, resulting in widespread tuneable functionality in their physiochemical properties. This review includes the details of most of the available routes of synthesis for amino acid surfactants (AASs) and the impact of the diverse routes on their final physiochemical properties, including solubility, dispersability, toxicity and biodegradability. The diversity offered by the structural variation in AASs offers many exciting commercial opportunities for this ever-growing class of surfactants. It also includes a discussion on current and future potential uses of AASs. 相似文献
42.
43.
Madhusudana Pulaganti Babajan Banaganapalli Chaitanya Mulakayala Suresh Kumar Chitta Anuradha C. M. 《Applied biochemistry and biotechnology》2014,172(3):1407-1432
Menaquinone is a lipid-soluble naphthoquinone that is essential for various pivotal functions of bacteria. Naphthoquinone is synthesized from chorismate of the shikimate pathway in microorganisms. Due to its absence in humans and animals, menaquinone biosynthesis has been an attractive target for development of antibiotics against a number of important microbial pathogens, such as Mycobacterium tuberculosis (Mtb). In shikimate pathway, O-succinylbenzoate synthase (OSBS) plays a major role and is one of the major potential drug targets. For Mtb-OSBS, a systematic study was conducted to get an insight about Mtb-OSBS enzyme and the corresponding inhibitors using in silico methods. The 3-D model of Mtb-OSBS was built using structure coordinates of Thermobifida fusca. O-succinylbenzoate synthase, the model, was further refined. The active site amino acids have been identified by comparing the template sequence with the Mtb-OSBS sequence. We identified that Lys108, Asn140, Asp138, Lys110, Glu189, Ser236, Asp188, Arg27, Tyr52, and Ser237 are highly conserved, and these may play a vital role as active residues, similar to that in template protein. As per the competitive binding of substrate (2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate (SHCHC)), we screened the SHCHC through AutoDock 4.0. The SHCHC molecule was further modified structurally and optimized through PRODRG server. Docking of the 12 lead molecules for best interactions with Mtb-OSBS has given an insight that all the lead molecules have shown interactions with active site amino acids of Mtb-OSBS. MD simulation analysis report has shown the stable conformation annotations of Mtb-OSBS. These hypothetical studies create another way to develop more potential drugs against the deadly mycobacterium. 相似文献
44.
Priyadarshini S. Sahoo Anuradha Panigrahi Sunanda K. Patri Rasm N. P. Choudhary 《Central European Journal of Physics》2010,8(4):639-642
A polycrystalline sample, Ba3Sr2DyTi3V7O30, with tungsten bronze structure was prepared by a mixed-oxide method at high temperature (950°C). Preliminary structural analysis of the compound showed an orthorhombic crystal structure at room temperature. Surface morphology of the compound was studied by scanning electron microscopy. The dielectric anomaly at 321°C may be attributed to the ferro-paraelectric phase transitions. This was also confirmed from the appearance of a hysteresis loop. The nature of variation of the ac conductivity and value of activation energy at different temperature regions, suggest that the conduction process is of mixed-type (i.e., ionic-polaronic and space charge generated from the oxygen ion vacancies). 相似文献
45.
Koushik Sarkar Anuradha Mukhopadhyay Katarzyna Garbat Roman Dabrowski 《Molecular Crystals and Liquid Crystals》2018,665(1):20-32
Optical and X-ray studies have been conducted on a four component liquid crystal mixture (code name 2013) with cyano–end groups in all the four components and a lateral substitution of fluorine atom in one of them. The variations in the optical birefringence with temperature, have been investigated and the thermal dependence of polarisability anisotropy and orientational order parameter have been evaluated. X-ray studies have been conducted to determine the effective molecular characteristics such as apparent molecular length and inter molecular distance and their variations with temperature. From nature of molecular alignment as envisaged from X-ray photographs the order parameter variation with temperature has been determined and compared with macroscopic order parameter variation as determined from birefringence studies. The results have been compared with these obtained for another structurally similar four-component liquid crystal mixture (code name 2014) with isothiocyanato end group in place of cyano. 相似文献
46.
Maheswata Moharana Anuradha Das Satya Narayan Sahu Subrat Kumar Pattanayak Fahmida Khan 《印度化学会志》2022,99(4):100417
Phytochemicals present in medicinal plants have a variety of biological activities that help to combat against diseases. As part of efforts to study the binding performance of different phytochemicals derived from different plants like Zingiber officinale, Citrus limon, Syzygiumaromaticum, Ocimum tenuiflorum and Curcumin. We have screened 424 molecules. The binding affinity as well as physicochemical properties of the thebaine, acacetin, indomethacin, crinamineacetate, (S)-1-Piperideine-6-carboxylate, levamisole, melatonin, nicotinicacid, curcumin, methotrimeprazine, omeprazole, and methaqualone phytocompounds were analyzed through computational study. From the molecular docking study we found that, LEU50, ASN72, PRO96, TYR154, GLY170, ALA193, ARG222, and MET274 residues of main protease play a crucial role in binding with ligands. The present study revealed a noticeable interaction of GLY446, SER477, GLY482, THR500 and LEU518 residues with mutant of spike receptor binding domain SARS-CoV-2 protein were observed. Finally, 100 ns molecular dynamics simulation were used to study their dynamic properties as well as conformational flexibility. Free energy landscape analysis was performed of the 6LU7- acacetin and 6Y2E-acacetin systems and spike RBD-acacetin system. From molecular docking study and molecular dynamics study revealed that, the compound acacetin shows promising inhibitor towards both main protease as well as mutant spike RBD of SARS-CoV-2 protein. 相似文献
47.
The photopolymerization of styrene in presence of an efficient, eco-friendly, and a cost-effective photoinitiator, curcumin,
which is found in turmeric root, has been reported for the first time. The catalytic concentration (10−6 M) of curcumin is effective to photoinitiate the polymerization of styrene. The kinetic data, inhibiting effect of benzoquinone
and electron spin resonance studies, indicate that the polymerization proceeds via a free radical mechanism. The system follows
non-ideal kinetics (R
p ∝ [Cur]0.36 [Sty]1.04) due to both primary radical termination and degradative chain transfer reactions. The broad peaks due to methine and methylene
protons in 1H-NMR (nuclear magnetic resonance [NMR]) spectrum and a band of resonances at 145–146 ppm in 13C-NMR indicate atactic nature of the polystyrene formed. The maximum conversion at 30 ± 0.2 °C in 17 h has been limited to
23% without gelation. The formation of radicals and mechanism of polymerization are also discussed. 相似文献
48.
C. Devendranath Reddy P. Mallikarjuna Reddy D. Ramasubba Reddy M. Nagalakshmamma K. Anuradha C. Naga Raju K. Darrell Berlin Kevin M. Couch Sameer Tyagi 《Journal of heterocyclic chemistry》1995,32(5):1483-1487
The synthesis of new 2,10-dichloro-6-aryloxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-sulfides 4 was achieved in two steps with high yields from the simple materials 5,5′-dichloro-2,2′-dihydroxydiphenyl-methane (1) and thiophosphoryl chloride (2) which produced the key intermediate 2,6,10-trichloro-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-sulfide (3) . Treatment of 3 with substituted phenols under phase transfer catalytic (PTC) conditions led to members of 4 . Long range coupling [5J(P,H) = 3.6 Hz] was observed between phosphorus and one of the bridged methylene protons in 4 . A 13C nmr analysis revealed 2J(P,O,C), 3J(P,O,C) 4J(P,O,C) and 5J(P,O,C) couplings. All 31P nmr chemical shifts for thirteen members of these new heterocycles are reported for the first time. The nmr data are not totally definitive to confirm a boat-chair as the major conformer for the central eight-membered dioxaphosphocin ring, but such a conformer is tentatively suggested as favored. 相似文献
49.
Zirconia beads (25-38 microm in diameter) were modified with N,N,N'.N'-ethylenediaminetetramethylenephosphonic acid to generate a pseudo-biospecific support, r_PEZ. To better understand the force of interaction between the IgG and the r_PEZ, the equilibrium dissociation constant (Kd) was determined by static binding isotherms, as a function of temperature and by frontal analysis at different linear velocities. Temperature had no significant impact on the maximum static binding capacity (Q(max)) and the equilibrium-binding constant (Kd), whereas pH and the salt concentration had a noticeable impact on both Q(max) and Kd values. Q(max) was found to be in the range of 55-65 mg IgG per ml of beads and unaffected by temperature. The maximum dynamic binding capacity (Qx) was found to be in the range of 20-12 mg IgG per ml of beads. The adsorption rate constant (ka) was determined by a split-peak approach to be between 982 and 32421 mol(-1) s(-1) depending on the linear velocity. Adsorption rate of IgG on r_PEZ was studied as a function of both feed concentration and linear velocity. The standard enthalpy and entropy values were estimated for the interaction of IgG with this novel support. The binding constants were also determined by modeling the batch protein-uptake data. 相似文献
50.