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331.
A D Tran S Park P J Lisi O T Huynh R R Ryall P A Lane 《Journal of chromatography. A》1991,542(2):459-471
Free solution capillary electrophoresis has been investigated as an alternative to isoelectric focusing for the separation of the glycoforms of recombinant human erythropoietin (r-HuEPO), a primary regulator of erythropoiesis. A systematic approach was used to study the effect of pH, buffer type and organic modifiers on the resolution of the microheterogeneity of erythropoietin. The main factors for improving the resolution were the regulation of the electroosmotic flow of the running buffer and the reduction of solute-wall interaction. The best resolution of the glycoforms of r-HuEPO was obtained with a mixed buffer pH 4.0 (100 mM acetate-phosphate, 10 h preequilibration time). 相似文献
332.
Robert J.P. Corriu Vijam Huynh Joël J.E. Moreau Magali Pataud-Sat 《Tetrahedron letters》1982,23(32):3257-3260
N,N-bis(silyl)enamines react with electrohiles in the presence of catalytic amounts of nucleophile. The reaction of carbonyl compounds catalyzed by fluoride ion provides an interesting route to 2?aza?1,3?dienes. The methoxide ion catalyzed reaction of N,N—dimethyl- formade gives rise to enamidines. 相似文献
333.
Mixed carbene-carboxylate complexes of Palladium(II) have been prepared by reacting {1,1′-dimethyl-3,3′-methylenediimidazoline-2,2′-diylidene} palladium(II) diiodide (1) [Angew. Chem. 107 (1995) 2602; Angew. Chem. Int. Ed. Engl. 34 (1995) 2371; J. Organomet. Chem. 557 (1998) 93] with AgO2CR, where R=CF3, CF2CF3 and CF2CF2CF3. In this manner, {1,1′-dimethyl-3,3′-methylenediimidazoline-2,2′-diylidene} palladium(II) bis(trifluo-roacetate) (2), {1,1′-dimethyl-3,3′-methylenediimidazoline-2,2′-diylidene} palladium(II) bis(pentafluoropropionate) (3) and {1,1′-dimethyl-3,3′-methylenediimidazoline-2,2′-diylidene} palladium(II) bis(heptafluorobutyrate) (4) were obtained. All three complexes were fully characterized by 1H-, 13C- and 19F NMR spectroscopy as well as ESI mass spectrometry. X-ray crystal structure analyses of complexes 3 and 4 reveal mononuclear species with a square planar metal center coordinated by a cis-chelating dicarbene and two monodentate carboxylate ligands. The results show that the introduction of a cis-chelating N,N-heterocyclic carbene ligand stabilizes the palladium-carboxylate moiety effectively. 相似文献
334.
Within the framework of a European interlaboratory exercise, the Vito facility for the generation of controlled atmospheres was used to test the suitability of four sampling techniques for priority aldehydes namely formaldehyde, acrolein, acetaldehyde, and glutaraldehyde at the ranges of 0.5 to 150 microg x m(-3). The samplers are DNPH-containing impingers, DNPH-impregnated cartridges and filters, and 2-HMP coated XAD-2 tubes. The three first DNPH samplers are to be analyzed by HPLC and the latter by GC-MS for the oxazolidine derivatives. The intermethod comparison comprises two to five sets of experiments depending on the compounds of interest. The aim of the exercise was also to assess the chemical interferences caused by ozone, nitrogen dioxide, and ammonia when using different techniques for sampling and analysis. The active DNPH method (with minor modifications such as shorter sampling time, immediate elution after sampling, and/or eventually wetting of samplers) delivered results within the 30% overall relative uncertainty for formaldehyde, acetaldehyde, and acrolein at the upper microg x m(-3) levels. However, the results suggest that the current DNPH methods for aldehydes do not comply with the 30% minimum performance criteria at the sub microg x m(-3) level. Sampling of aldehydes in the presence of ozone and NO2 interferences by using a "scrubber" cartridge appears to be beneficial to the quality of results. 相似文献
335.
Synthesis, characterization, and energetic properties of diazido heteroaromatic high-nitrogen C-N compound 总被引:16,自引:0,他引:16
Huynh MH Hiskey MA Chavez DE Naud DL Gilardi RD 《Journal of the American Chemical Society》2005,127(36):12537-12543
The synthesis, characterization, and energetic properties of diazido heteroaromatic high-nitrogen C-N compound, 3,6-diazido-1,2,4,5-tetrazine (DiAT), are reported. Its normalized heat of formation (NDeltaHf), experimentally determined using an additive method, is shown to be the highest positive NDeltaHf compared to all other organic molecules. The unexpected azido-tetrazolo tautomerizations and irreversible tetrazolo transformation of DiAT are remarkable compared to all other polyazido heteroaromatic high-nitrogen C-N compounds, for example, 2,4,6-triazido-1,3,5-triazine; 4,4',6,6'-tetra(azido)hydrazo-1,3,5-triazine; 4,4',6,6'-tetra(azido)azo-1,3,5-triazine; and 2,5,8-tri(azido)-1,3,4,6,7,9,9b-heptaazaphenalene (heptazine). 相似文献
336.
Melvyn Rowen Churchill Lynn M. Krajkowski My Hang Vo Huynh Kenneth J. Takeuchi 《Journal of chemical crystallography》1996,26(2):111-116
The complexcis-[Ru(bpy)2 {PPh2(o-tol)}Cl][ClO4] crystallizes from dichloromethane as the sesqui-dichloromethane solvate. The complex crystallizes in the monoclinic space group P21/n with Z=4. The structure was refined toR=5.50% for those 2552 independent reflections with |F
0|>6(|F
0|) The octahedral Ru(II) cation is associated with the following bond lengths: Ru-PPh2(o-tol)=2.360(3)Å. Ru–Cl=2.433(2)Å and Ru–N(bpy)=2.041(8)–2.095(8)Å. Both the perchlorate anion and the dichloromethane molecules of solvation exhibit large amplitudes of vibration. One dichloromethane molecule lies in a general position, the other lies about an inversion center and suffers from disorder. 相似文献
337.
Dr. Anthony K. Au Wilson Huynh Dr. Lisa F. Horowitz Dr. Albert Folch 《Angewandte Chemie (International ed. in English)》2016,55(12):3862-3881
The advent of soft lithography allowed for an unprecedented expansion in the field of microfluidics. However, the vast majority of PDMS microfluidic devices are still made with extensive manual labor, are tethered to bulky control systems, and have cumbersome user interfaces, which all render commercialization difficult. On the other hand, 3D printing has begun to embrace the range of sizes and materials that appeal to the developers of microfluidic devices. Prior to fabrication, a design is digitally built as a detailed 3D CAD file. The design can be assembled in modules by remotely collaborating teams, and its mechanical and fluidic behavior can be simulated using finite‐element modeling. As structures are created by adding materials without the need for etching or dissolution, processing is environmentally friendly and economically efficient. We predict that in the next few years, 3D printing will replace most PDMS and plastic molding techniques in academia. 相似文献
338.
ABSTRACTTin-doped indium oxide (ITO) nanoparticles (NPs) were conceived as promising materials using as noncarbon support for Pt NPs on the cathode side of Proton Exchange Membrane Fuel Cells (PEMFC). In this paper, ITO nanoparticles have been synthesized via a nonaqueous sol-gel process using indium acetylacetonate and tin bis(acetylacetonate)dichloride in oleyamine as starting materials. The ITO exhibits solid solution phase, relatively porous, good crystallinity with a uniform size of 15–20 nm, resulting in a high specific surface area and excellent conductivity. The effects of reaction temperature, calcination temperature on the specific surface area as well as the conductivity of ITO nanoparticles were studied in this paper. We found that the ITO nanoparticles synthesized at 235°C and calcination temperature at 500°C for 3 hours shows the excellent conductivity of 1.242 S/cm, was significantly ~8-fold higher than that of commercial ITO produced by Sigma-Aldrich (0.15 S/cm). The results of this research suggested that the ITO synthesized by non-aqueous sol-gel process exhibits relatively good properties as well as can apply this process to prepare the others nanomaterial support based on In2O3-materials by doping different oxide into indium oxide. 相似文献
339.
340.
Structures and Bonding Situation of Iron Complexes of Group‐13 Half‐Sandwich ECp* (E = B to Tl) Based on DFT Calculations
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Thi Ai Nhung Nguyen Thi Phuong Loan Huynh Thai Hoa Tran Van Tat Pham Tuan Quang Duong Tan Hiep Dang 《无机化学与普通化学杂志》2016,642(8):609-617
Quantum chemical calculations at the BP86 level with various basis sets (SVP, TZVPP, and TZ2P+) were carried out for the Fe(CO)4 of group‐13 half‐sandwich ECp* [Fe(CO)4‐ECp*] ( Fe4‐E ) (E = B to Tl). The chemical bonding of the Fe(CO)4‐ECp* bond was analyzed with charge‐ and energy decomposition methods. The calculated equilibrium structures of complexes Fe4‐E show that the ligands ECp* are bonded in an end‐on way to the fragment Fe(CO)4 in Fe4‐E with E = B to Ga. The compound Fe4‐In has a distorted end‐on ligand InCp*. In contrast, Fe4‐Tl has a side‐on bonded ligand TlCp*. The calculated bond dissociation energies (BDEs) suggest that the bond in the iron group‐13 half‐sandwich complexes Fe4‐E decreases from Fe4‐B to Fe4‐Tl . Natural bond orbital (NBO) analysis of the bonding situation reveals that the Fe(CO)4←ECp* donation in Fe4‐E comes from the σ lone‐pair orbital of ECp*. Bonding analysis indicates that the ligand ECp* in complexes are strong σ donors and the NOCV pairs of the bonding show small π‐back donation from the Fe(CO)4 to the ECp* ligands. 相似文献