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991.
Hitoxhi Fujimori Yasutaka Kayama Takeshi Hara Kazuhiko Itoh Tamiko Sunami 《Journal of heterocyclic chemistry》1977,14(2):235-240
The synthesis of 4H-pyrrolo[1,2-a]thieno[3,2-f] [1,4]diazepines ( 8 ) is described. Phthal-imidomethylfurans 1 were treated with bromine-methanol to give the dihydrofurans 2 , which were hydrolyzed and then liydrogenated over Raney nickel or with zinc-acetic acid to afford the 1,4-diketones 5 . Condensation of 2-amino-3-benzoylthiophenes 6 with 5 gave 3-benzoyl-2-pyrrolylthiopenes 7 . The removal of the phthaloyl group from 7 with hydrazine hydrate and ring closure to the diazepine ring yielded the new heterocycles 8 . 相似文献
992.
Kazuhiko Hashimoto Hiroshi Sumitomo 《Journal of polymer science. Part A, Polymer chemistry》1969,7(6):1549-1555
Further investigation on an anionic polymerization of β-cyanopropionaldehyde was made with use of polystyryl—disodium, naphthalene—sodium, and tetraphenylethylenedisodium complexes as initiators. Styrene—β-cyanopropionaldehyde block copolymer was separated from the gross polymer obtained by the polymerization of β-cyanopropionaldehyde with polystyryl—sodium. The polymerization initiated by naphthalene—sodium and tetraphenylethylene—disodium complexes resulted in the formation of an aldol condensation-type product having a low molecular weight. It was found that initiators of weaker basicity may start the carbonyl polymerization, whereas those of stronger basicity cause the aldol condensation of β-cyanopropionaldehyde through the withdrawal of proton from the monomer. 相似文献
993.
994.
Ito K Sakamoto J Nagaoka K Takayama Y Kanahori T Sunahara H Hayashi T Sato S Hirokawa T Tanaka K 《色谱》2012,30(4):369-373
The analysis of seven aliphatic carboxylic acids(formic,acetic,propionic,iso-butyric,n-butyric,iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents(benzoic acid,perfluorobutyric acid(PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet(UV) detection.The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column(TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column(TSKgel Super IC-A/C).Good separation was performed on the TSKgel SCX in shorter retention times.For the TSKgel Super IC-A/C,peak shape of the acids was sharp and symmetrical in spite of longer retention times.In addition,the mutual separation of the acids was good except for iso-and n-butyric acids.The better separation and good detection was achieved by using the two columns(TSKgel SCX and TSKgel Super IC-A/C connected in series),lower concentrations of PFBA and sulfuric acid as eluents,non-suppressed conductivity detection and UV detection at 210 nm.This analysis was applied to anaerobic digestion process waters.The chromatograms with conductivity detection were relatively simpler compared with those of UV detection.The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices. 相似文献
995.
We developed an FIA system equipped with a chemiluminescence detector using a mixed chemiluminescence reagent of luminol and 1,10-phenanthroline for the detection of metal ions and metal complexes. The carrier, mixed chemiluminescence reagent comprising luminol, 1,10-phenanthroline, and cethyltrimethylammonium bromide, and H2O2 solutions were fed by corresponding pumps at a definite flow rate. Sample solutions dissolving hematin, [Co(NH3)4(H2O)2]2(SO4)3, CuSO4, NiCl2, K3[Fe(CN)6], and K4[Fe(CN)6] were analyzed as models by the means of the present FIA system. Solutions of hematin, [Co(NH3)4(H2O)2]2(SO4)3, CuSO4, and NiCl2 were detected as positive peaks, as usual. The order of the catalytic activity of these samples for the present chemiluminescence reaction using the mixed chemiluminescence reagent was [Co(NH3)4(H2O)2]2(SO4)3 > hematin > CuSO4 > NiCl2. On the other hand, sample solutions of K3[Fe(CN)6] and K4[Fe(CN)6] were detected as negative peaks and were determined over the ranges of 1 x 10(-8) - 1 x 10(-6) M with a detection limit of 1 x 10(-8) M and 2 x 10(-8) - 4 x 10(-6) M with a detection limit of 2 x 10(-8) M, respectively. Their negative peaks were observed reproducibly with a relative standard deviation of 2 - 5%. 相似文献
996.
997.
998.
999.
A simple, sensitive and rapid ion-exclusion chromatographic method for the simultaneous separation of carbonic acid and short chain organic acids (formic acid, acetic acid, and propionic acid) has been developed. A weakly acidic cation exchange resin column TSKgel OApak-A was used for the separation; pure water, owing to its lower background conductance, was employed as eluent in order to obtain high detection sensitivity. A good separation of these weak acids was achieved in 16 min. The linear range of the peak area calibration curve for carbonic acid was from 3.0 mg/L to 500 mg/L. The conductivity detection limit calculated at S/N = 3 was 0.084 mg/L for carbonic acid. The method developed in this work was successfully applied to the determination of carbonic acid in several environmental water samples without any pretreatment. 相似文献
1000.
We have developed a consecutive sample-injection device for capillary electrophoresis, which comprises one four-way cock, two syringe pumps, and an interface part taking advantage of two three-way Teflon joints. Sample introduction into the capillary is made hydrodynamically by pressure, caused by the flow of the sample solution at the tip of the capillary inlet. We combined the injection device with a capillary electrophoresis-chemiluminescence detection system. A mixture solution of N-(4-aminobutyl)-N-ethylisoluminol, isoluminol isothiocyanate, and luminol was analyzed as a model sample by the present system. The sample solution was consecutively injected and detected with about a 230 s interval. The present capillary electrophoresis-chemiluminescence detection system with the consecutive sample injection device features easy and rapid operation, an inexpensive apparatus, high sensitivity, as well as consecutive analysis. 相似文献