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231.
Yasuto Tsuruta Hirofumi Inoue Keiko Fukunaga Sayaka Munemura Misa Ozaki Masaya Ohta Fumito Matsuura 《Analytical sciences》2005,21(6):697-699
A highly sensitive method for the determination of bisphenol-A in water with semi-micro column high-performance liquid chromatography using 2-methoxy-4-(2-phthalimidinyl)phenylsulfonyl chloride as a fluorescent labeling reagent has been developed. The labeling reaction was carried out at 70 degrees C for 20 min in borate buffer (pH 9.5). The derivative eluted at 11.6 min on a reversed-phase column with methanol-water (78:22, v/v) at a flow-rate of 0.2 ml/min. The fluorescence was monitored at 308 nm for excitation and 410 nm for emission. The detection limit (S/N = 3) was 10 fmol per injection. The labeling yield was about 95%. 相似文献
232.
Masaya Toda Yoshihiko Kondo Fumio Hamada 《Journal of inclusion phenomena and macrocyclic chemistry》2007,59(3-4):341-344
The supramolecular assembly system based on bis naphtahlene modified β-cyclodextrin dimer linked with ethylenediamine unit
was studied. The synthesis of the titled compound (β-1) was succeeded in a 7% synthetic yield. It was observed that β-1 showed
monomer emission, which was decreased concurrently with appearance of excimer emission in an addition of guest species such
as 1-adamantanol or ursodeoxycholic acid. When γ-CyD was added to the system, two types of fluorescent spectra were obtained,
which was depended on guest species. It was indicated that both of naphthalene units of β-1 were included in the γ-CyD cavity
in the presence of 1-adamantanol in a fashion of 2:1 complex. On the other hand, an addition of ursodeoxycholic acid gave
disappearance of the excimer emission as well as increase of monomer emission. In the system, each of the appended units was
trapped by the each of two γ-CyDs, which is 2:2 complex formation. 相似文献
233.
Fischer carbene complexes having long alkynyloxy chains regioselectively produced oxametacyclophanes via the intramolecular Dötz reaction. The utility of this reaction was demonstrated in the synthesis of arnebinol, an ansa-type terpenoid, from geranyl acetate in six steps. 相似文献
234.
235.
In the absence of any additional catalysts, the reactions of (CF(3)SO)(2)CH(2), aldehydes, and 1,3-dienes gave gem-bis(triflyl)cyclohexenes in excellent yields with high regioselectivity. gem-Bis(triflyl)cyclohexene products can be easily converted to the corresponding aryl trifluoromethyl sulfones. 相似文献
236.
Yamakoshi H Dodo K Okada M Ando J Palonpon A Fujita K Kawata S Sodeoka M 《Journal of the American Chemical Society》2011,133(16):6102-6105
Click-free imaging of the nuclear localization of an alkyne-tagged cell proliferation probe, EdU, in living cells was achieved for the first time by means of Raman microscopy. The alkyne tag shows an intense Raman band in a cellular Raman-silent region that is free of interference from endogenous molecules. This approach may eliminate the need for click reactions in the detection of alkyne-labeled molecules. 相似文献
237.
A mixture of alkyl 1,4-dihydro-2-methylthio-4,4,6-trisubstituted pyrimidine-5-carboxylate 1 and its tautomeric isomer, alkyl 1,6-dihydro-2-methylthio-4,6,6-trisubstituted pyrimidine-5-carboxylate 2 is synthesized by the Atwal-Biginelli cyclocondensation reaction of S-methylisothiourea hemisulfate salt 3 with 2-(gem-disubstituted)methylene-3-oxoesters 4 that can be accessed by the Lehnert procedure for the Knoevenagel-type condensation. The structures of the tautomeric products of the Atwal-Biginelli cyclocondensation reaction, 1 and 2, which are inseparable from each other, are determined unambiguously by (1)H-NMR spectroscopy at various temperatures and nuclear Overhauser enhancement spectroscopy (NOESY) experiment. Because these dihydropyrimidine products are otherwise inaccessible and thus hitherto unavailable, the synthetic methods established in this study will help to expand the molecular diversity of their related derivatives. 相似文献
238.
Shin-ichi Kondo Masanori NagamineSatoshi Karasawa Masaya IshiharaMasafumi Unno Yumihiko Yano 《Tetrahedron》2011,67(5):943-950
Synthesis and anion recognition properties of 2,2′-binaphthalene derivatives bearing two thiourea (1) and urea (2) groups at 8- and 8′-positions were studied. The structure of receptor 1 was determined by X-ray crystallography. UV-vis spectra of the receptors showed characteristic changes around 300-400 nm through isosbestic points upon the addition of biologically relevant anions such as acetate, dihydrogenphosphate, and chloride in MeCN and DMSO due to restriction of the rotation around the single bond connecting two naphthyl moieties by cooperative guest binding of two recognition sites. Job’s plots showed 1:1 complexation for guest anions. The fluorescence quantum yields of free form of 1 and 2 in MeCN were determined to be 0.021 and 0.57, respectively. The fluorescence intensities of the receptors diminished upon the addition of anions in MeCN. The association constants of receptors 1 and 2 were one or two orders of magnitude greater than the corresponding monothiourea and urea receptors 3 and 4 indicating cooperative hydrogen bonding with guest anions. The selectivity trends of association of anions were F−>AcO−>H2PO4−>Cl−>>HSO4−≈NO3−≈Br−≈I− for 1, and F−>AcO−≈Cl−>H2PO4−>Br−>HSO4−>I−≈NO3− for 2. Receptor 2 showed remarkable Cl− selectivity presumably owing to suitable orientation for effective hydrogen bond formation with Cl−. 相似文献
239.
Prof. Dr. Masahiro Sadakane Niklas Rinn Sachie Moroi Hiroaki Kitatomi Tomoji Ozeki Mariko Kurasawa Masaya Itakura Shinjiro Hayakawa Kazuo Kato Mayumi Miyamoto Shuhei Ogo Yusuke Ide Tsuneji Sano 《无机化学与普通化学杂志》2011,637(11):1467-1474
RuII‐ and RuIII‐substituted α‐Keggin‐type phosphotungstates with a dimethyl sulfoxide (DMSO) ligand, [PW11O39RuIIDMSO]5– ( 1 ) and [PW11O39RuIIIDMSO]4– ( 2 ), were synthesized. Compound 1 was prepared by reaction of [PW11O39]7– with [RuII(DMSO)4]Cl2 in water at 125 °C under hydrothermal conditions and was isolated as a cesium salt. Compound 2 was prepared by reaction of 1 with bromine in water at 60 °C and was isolated as a cesium salt. The compounds were characterized by cyclic voltammetry, elemental analysis, UV/Vis, IR,31P NMR, 183W NMR, 1H NMR, and XANES (Ru K‐edge and L3‐edge)spectroscopic methods. Single crystal structural analysis of 1 revealed that RuII is incorporated in the α‐Keggin framework and coordinated by DMSO through a Ru–S bond. Cyclic voltammetry of 1 indicated that the incorporated RuII‐DMSO is reversibly oxidizable to the RuIII‐DMSO derivative 2 . Compound 1 showed catalytic activity for water oxidation in the presence of cerium ammonium nitrate as an oxidant. 相似文献
240.
Inokuma T Furukawa M Uno T Suzuki Y Yoshida K Yano Y Matsuzaki K Takemoto Y 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(37):10470-10477
Hydrogen-bond (HB)-donor catalysts that bear a 2-aminoquinazolin-4-(1H)-one or a 3-aminobenzothiadiazine-1,1-dioxide skeleton have been developed, and it has been shown that these catalyst motifs act similarly to other HB-donor catalysts such as thioureas. The highly enantioselective hydrazination of 1,3-dicarbonyl compounds was realized even at room temperature with up to 96% ee for 2-aminoquinazolin-4-(1H)-one-type catalysts, which were more effective than the corresponding urea and thiourea catalysts. In addition, benzothiadiazine-1,1-dioxide-type catalysts were shown to promote the isomerization of alkynoates to allenoates with high enantioselectivity. To overcome the problem that the products were obtained as mixtures with the starting alkynoates, we developed the tandem isomerization and cycloaddition of alkynoates for the synthesis of advanced chiral compounds such as bicyclo[2.2.1]heptenes and 3-alkylidene pyrrolidine without a significant loss of enantioselectivity. 相似文献