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101.
S. K. Malik G. K. Shenoy P. L. Paulose R. Nagarajan A. E. Dwight P. P. Vaishnava C. W. Kimball 《Hyperfine Interactions》1987,34(1-4):377-380
The compounds EuPdGa and EuPtGa show lattice volume anomaly indicating the abnormal valence state of Eu. in these compounds. Magnetization studies reveal that these compounds are magnetically ordered with a moment of 7 B/f.u. at 5K. The Curie temperatures obtained from the low field ac susceptibility measurements are 38K for EuPdGa and 36K for EuPtGa.151Eu Mössbauer studies at 300K gave large negative isomer shifts (relative to SmF3) and show a hyperfine split pattern at 4.2K in both the compounds. These results suggest that Eu is in a divalent state in EuPdGa and EuPtGa. 相似文献
102.
Reaction of 1-(2-nitrophenoxy)naphthalene or its β-isomer with triethylphosphite produces benzo[a]phenoxazines and , through the intermediate . 相似文献
103.
Dr. Kenkera Rayappa Naveen Dr. Rajendra Kumar Konidena P. Keerthika 《Chemical record (New York, N.Y.)》2023,23(11):e202300208
Since their first demonstration, thermally activated delayed fluorescence (TADF) materials have been emerged as the most promising emitters because of their promising applications in optoelectronics, typified by organic light-emitting diodes (OLEDs). In which, the rigid oxygen bridged boron acceptor-featured ( DOBNA ) emitters have gained tremendous impetus for OLEDs, which is ascribed to their excellent external quantum efficiency (EQE). However, these materials often displayed severe efficiency roll-off and poor operational stability. Therefore, there needs to be a comprehensive understanding of the aspect of the molecular design and structure-property relationship. To the best of our knowledge, there is no detailed review on the structure-function outlook of DOBNA -based emitters emphasizing the effect of the nature of donor units, their number density, and substitution pattern on the physicochemical properties, excited state dynamics and OLED performance were reported. To fill this gap, herein we presented the recent advancements in DOBNA -based acceptor featured TADF materials by classifying them into several subgroups based on the molecular design i. e. donor-acceptor (D−A), D−A-D, A−D-A, and multi-resonant TADF (MR-TADF) emitters. The detailed design concepts, along with their respective physicochemical and OLED performances were summarized. Finally, the prospective of this class of materials in forthcoming OLED displays is also discussed. 相似文献
104.
Nagarajan NS Rao RP Manoj CN Sethuraman MG 《Magnetic resonance in chemistry : MRC》2005,43(3):264-265
An alcoholic extract of Dalbergia sympathetica, on column chromatography, yielded a compound which analyzed for C(6)H(11)NO(3) (M(+) 145). The IR spectrum of the compound showed the presence of carbonyl and hydroxyl groups. PMR, (13)C and DEPT NMR spectral studies of the compound showed the presence of one N-methyl, two methine and two methylene groups. A quaternary carbon signal at delta 172.88 ppm was assigned to C-2 carbonyl of the compound. From all the above observations and also from the HMQC 2D NMR spectrum, the compound was identified as 3, 6-dihydroxy-N-methyl-2-piperidone. This is the first report of the natural occurrence of this compound from plant sources. 相似文献
105.
This article discusses the extraction and characterization of new natural fiber extracted from red coconut empty fruit bunch. The physicochemical, mechanical, and thermal properties of alkali-treated red coconut empty fruit bunch fibers (ARCEFBFs) were reported and compared with other natural fibers for the first time. Cellulose content (65.02 wt%), wax (0.32 wt%), density (1.421 g/cc), and tensile strength (1299.49 MPa) were identified in ARCEFBFs. Fourier transform infrared spectroscopy and X-ray diffraction analysis confirmed that ARCEFBFs are rich in cellulose content with crystallinity index of 53.6%. Thermogravimetric analysis revealed that these fibers are thermally stable until 270.48°C. 相似文献
106.
Narayanan MC Rao PR Shanmugam NN Gopalakrishnan SM Devi K 《Natural product research》2007,21(10):903-909
The roots of Dalbergia horrida yielded two new isoflavanones, Dalhorridin (I) - 5,5'-dihydroxy-3',4'-methylenedioxy-5'-prenyl-6',6'-dimethyl-dihydropyrano(2',3' : 7,8)-isoflavanone and Dalhorridinin (II) - 5,7,5'-trihydroxy-3',4'-methylenedioxy-8-[5-methyl-2-(2-hydroxyisopropyl)-1,4-hexadienyl]isoflavanone along with two known isoflavones, Dalspinin and Dalspinosin. Preliminary biological screening of the enriched extract revealed that it showed analgesic, anti-inflammatory, CNS depressant and mild anti-bacterial properties. 相似文献
107.
Li Y Zhu F Vaidehi N Goddard WA Sheinerman F Reiling S Morize I Mu L Harris K Ardati A Laoui A 《Journal of the American Chemical Society》2007,129(35):10720-10731
Prostanoids play important physiological roles in the cardiovascular and immune systems and in pain sensation in peripheral systems through their interactions with eight G-protein coupled receptors. These receptors are important drug targets, but development of subtype specific agonists and antagonists has been hampered by the lack of 3D structures for these receptors. We report here the 3D structure for the human DP G-protein coupled receptor (GPCR) predicted by the MembStruk computational method. To validate this structure, we use the HierDock computational method to predict the binding mode for the endogenous agonist (PGD2) to DP. Based on our structure, we predicted the binding of different antagonists and optimized them. We find that PGD2 binds vertically to DP in the TM1237 region with the alpha chain toward the extracellular (EC) region and the omega chain toward the middle of the membrane. This structure explains the selectivity of the DP receptor and the residues involved in the predicted binding site correlate very well with available mutation experiments on DP, IP, TP, FP, and EP subtypes. We report molecular dynamics of DP in explicit lipid and water and find that the binding of the PGD2 agonist leads to correlated rotations of helices of TM3 and TM7, whereas binding of antagonist leads to no such rotations. Thus, these motions may be related to the mechanism of activation. 相似文献
108.
Kuppuswamy Nagarajan 《Journal of Chemical Sciences》2006,118(4):291-309
My professional research career spanning more than four decades has been largely devoted to synthetic medicinal chemistry
(Ciba, Bombay — now Mumbai — 21 years) followed by an equal number of years in process development of drugs, crop protection
chemicals (Searle, Bombay) and drugs and speciality chemicals (Recon and Hikal, Bangalore). These efforts have involved several
collaborators including many from other institutions and offered multitudinous challenges calling for continuous creativity
in industrial setups. I was fortunate to have had a conducive environment to be able to respond to these challenges. I attempt
to offer the readers in the ensuing pages a flavour of the excitement that has marked these years
Presented at the 7th Chem. Res. Soc. of India (CRSI) Conference in Kolkata, February 4–6, 2005 相似文献
109.
Two series of thiol-bridged dimeric desoxo molybdenum(IV) and tungsten(IV) bis(dithiolene) complexes, [Et(4)N](2)[M(IV)(2)(SR)(2)(mnt)(4)] [M = Mo, R = (1) -Ph, (2) -CH(2)Ph, (3) -CH(2)CH(3), (4) -CH(2)CH(2)OH; M = W, R = (1a) -Ph, (2a) -CH(2)Ph, (3a) -CH(2)CH(3), (4a) -CH(2)CH(2)OH] and one monomeric desoxo complex, [Et(4)N](2)[WIV(SPh)(2)(mnt)(2)] (5a) are reported. These complexes are diamagnetic, and crystal structures of each of the complex (except 5a) exhibits a dimeric {M(IV)(2)(SR)(2)} core without any metal-metal bond where each metal atom possesses hexa coordination. The M-SR distance ranges from 2.437 to 2.484 Angstrom in molybdenum complexes and from 2.418 to 2.469 Angstrom in tungsten complexes. These complexes display Mo-S(R)-Mo angles ranging from 92.84 degrees to 96.20 degrees in the case of 1-4 and W-S(R)-W angles ranging from 91.20 degrees to 96.25 degrees in the case of 1a-4a. Interestingly, both the series of Mo(IV) and W(IV) dimeric complexes respond to an unprecedented interconversion between the dimer and the corresponding hexacoordinated monomer upon change of pH. This pH-dependent interconversion establishes the fact that even the pentacoordinated Mo(IV) and W(IV) bis(dithiolene) moieties are forced to dimerize; these can easily be reverted back to the corresponding monomeric complex, reflecting the utility of dithiolene ligand in stabilizing the Mo(IV)/W(IV) moiety in synthesized complexes similar to the active sites present in native proteins. 相似文献
110.
We study a multiple-vehicle routing problem with a minimum makespan objective and compatibility constraints. We provide an approximation algorithm and a nearly-matching hardness of approximation result. We also provide computational results on benchmark instances with diverse sizes showing that the proposed algorithm (i) has a good empirical approximation factor, (ii) runs in a short amount of time and (iii) produces solutions comparable to the best feasible solutions found by a direct integer program formulation. 相似文献