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1.
A micro-phase sorbent in situ formation from an aqueous solution was proposed for the sensitive spectrophotometric determination of nitrite in environmental waters. Nitrite in a 10 mL sample solution was converted into a cationic azo dye by the reaction with 4-trifluoromethylanilinium ion and N-1-naphthylethylenediammonium ion in an acidic medium. Addition of dodecylbenzenesulfonate ion caused the formation of a suspension of ion associate in the solution. Centrifugation of the solution led to the isolation of a liquid organic phase that extracted the azo dye at the bottom of the centrifuge tube. The volume of the new phase was ca. 5 microL. After the aqueous phase was discarded, the organic phase was dissolved with 1 mL of 2-methoxyethanol to measure the absorbance. Nitrogen as NO2- at concentrations from 1.5 to 30 microg L(-1) was determined with sufficient precision. When 0.2 mL of 2-methoxyethanol was applied to dissolve the organic phase, 0.3-4.8 microg NO2--N L(-1) was determined. The recovery tests for nitrite added to some river water and seawater were satisfactory. This method is very simple and rapid. It takes only 30 min from the dye formation to the measurement of the absorbance. 相似文献
2.
Ryosuke Sakai Issei Otsuka Toshifumi Satoh Ryohei Kakuchi Harumi Kaga Toyoji Kakuchi 《Journal of polymer science. Part A, Polymer chemistry》2006,44(1):325-334
The asymmetric polymerization of 4′‐isocyanatobenzo‐18‐crown‐6 with the lithium amide of (S)‐(2‐methoxymethyl)pyrrolidine successfully proceeded to afford end‐functionalized poly(4′‐isocyanatobenzo‐18‐crown‐6) with (S)‐(2‐methoxymethyl)pyrrolidine (polymer 2 ). In the circular dichroism (CD) spectrum of 2 , a clear positive Cotton effect was observed in the range of 240–350 nm corresponding to the absorption of the polymer backbone, indicating that 2 partially formed a one‐handed helical structure, which was preserved by the chirality of (S)‐(2‐methoxymethyl)pyrrolidine bonding to the terminal end in 2 . In the titration experiments for the CD intensity of 2 in the presence of D ‐ and L ‐Phe·HClO4 (where Phe is phenylalanine), a small but remarkable difference was observed in the amount of the chiral guest needed for saturation of the CD intensity and in the saturated CD intensity, indicating that the extremely stable, one‐handed helical part should exist in the main chain of 2 , which was not inverted even when the unfavorable chiral guest for the predominant helical sense, L ‐Phe·HClO4, was added. In addition, helical polymer 2 exhibited a chiral discrimination ability toward racemic guests; that is, the guests were extracted from the aqueous phase into the organic phase with enantiomeric excess. The driving force of the chiral discrimination ability of 2 should certainly be attributed to the one‐handed helical structure in 2 . © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 325–334, 2006 相似文献
3.
Albrecht H Binder U Harder G Lembke-Koppitz I Philipp A Schmidt-Parzefall W Schröder H Schulz HD Wurth R Donker JP Drescher A Matthiesen U Scheck H Spaan B Spengler J Wegener aD Gabriel JC Schubert KR Stiewe J Waldi R Weseler S Brown NN Edwards KW Frisken WR Fukunaga C Gilkinson DJ Gingrich DM Goddard M Kapitza H Kim PC Kutschke R MacFarlane DB McKenna JA McLean KW Nilsson AW Orr RS Padley P Patel PM Prentice JD Seywerd HC Stacey BJ Yoon T Yun JC Ammar R Coppage D Davis R Kanekal S Kwak N 《Physical review letters》1986,56(6):549-552
4.
Phenotyping of erythrocyte acid phosphatase (EAP) and esterase D (ESD) by cellulose acetate membrane isoelectric focusing (CAM-IEF) under a nonequilibrium condition is described. In an attempt to improve the method of CAM-IEF, we shortened the electrode distance to provide a higher field strength at a given (low) voltage. Various carrier ampholytes for EAP typing and various chemical separators for ESD typing were also tested. Good separations were obtained after 30 min IEF for EAP typing and 25 min for ESD typing. When applied to blood stains and stored for various periods at room temperature, the stains up to 8 months old could still be phenotyped for EAP and those up to 4 weeks old for ESD. CAM-IEF is suitable for routine forensic work of EAP and ESD phenotyping. 相似文献
5.
Norio Miyoshi Kiyoaki Hara Issei Yokoyama Giiti Tomita Masaru Fukuda 《Photochemistry and photobiology》1988,47(5):685-688
Abstract— The absorption and fluorescence spectra, and the fluorescence lifetime of acridine orange (AO) were measured in a wide range of the sodium dodecyl sulfate (SDS) concentration below and above the critical micelle concentration (cmc). The fluorescence consisted of two components with different lifetimes; short (<3 ns) and long (>3 ns). The short and long lifetime components are attributed to the AO monomer and dimer associated with detergent, respectively. The lifetime of the dimer increased with increasing the SDS concentration just below the cmc. It decreased suddenly to a constant value just above the cmc. The lifetime of the monomer showed only a slight increase in the concentration range of SDS employed. 相似文献
6.
Anucha Wannagon Rikuo Ota Takashi Wakasugi Jiro Fukunaga 《Journal of Sol-Gel Science and Technology》2000,19(1-3):795-798
SiO2-TiO2-ZrO2 and 5Na2O·95(SiO2 + TiO2 + ZrO2) gels were synthesized and role of Na2O in gel formation and crystallization behavior of gels were studied. From Si(OC2H5)4, Ti(iso-OC3H7)4, Zr(n-OC3H7)4 and NaOCH3 solutions in EtOH without H2O, transparent and opaque gels were obtained. Opaque bulk gels, rich in TiO2 or ZrO2 composition in Na2O containing SiO2-TiO2-ZrO2 system, contain agglomerated spherical particles of diameter small <10 m, in contrast with opaque gels having large particles <30 m in alkali-free SiO2-TiO2-ZrO2 system. Crystallization temperature (Tc) was measured by DTA on dried gels. Compared with the alkali-free SiO2-TiO2-ZrO2 gels, 5 mol% Na2O containing gels gave lower Tc in SiO2 rich compositions and higher in TiO2 rich or ZrO2 rich compositions. 相似文献
7.
N Otsuka M Fukunaga K Morita S Ono K Nagai T Furukawa S Yanagimoto T Tomomitsu H Kawahara H Tanaka 《Radioisotopes》1988,37(6):330-335
In order to detect the varicocele, scrotal scintigraphies by using 99mTc-HSA-D were performed in 14 patients with male infertile or palpable mass in left scrotum on physical examinations. Abnormal pooling of 99mTc-HSA-D, indicative of varicocele lesion, could be found in left scrotum in 9 cases, confirmed surgically or clinically. Compared with 99mTc-HSA, 99mTc-HSA-D was superior in high uptake ratio of varicocele to soft tissue and in nonvisualization of bladder. Thus, 99mTc-HSA-D scrotal scintigraphy seemed to be of a great use to detect the varicocele. 相似文献
8.
Nishibayashi Y Milton MD Inada Y Yoshikawa M Wakiji I Hidai M Uemura S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(5):1433-1451
The scope and limitations of the ruthenium-catalyzed propargylic substitution reaction of propargylic alcohols with heteroatom-centered nucleophiles are presented. Oxygen-, nitrogen-, and phosphorus-centered nucleophiles such as alcohols, amines, amides, and phosphine oxide are available for this catalytic reaction. Only the thiolate-bridged diruthenium complexes can work as catalysts for this reaction. Results of some stoichiometric and catalytic reactions indicate that the catalytic propargylic substitution reaction proceeds via an allenylidene complex formed in situ, whereby the attack of nucleophiles to the allenylidene C(gamma) atom is a key step. Investigation of the relative rate constants for the reaction of propargylic alcohols with several para-substituted anilines reveals that the attack of anilines on the allenylidene C(gamma) atom is not involved in the rate-determining step and rather the acidity of conjugated anilines of an alkynyl complex, which is formed after the attack of aniline on the C(gamma) atom, is considered to be the most important factor to determine the rate of this catalytic reaction. The key point to promote this catalytic reaction by using the thiolate-bridged diruthenium complexes is considered to be the ease of the ligand exchange step between a vinylidene ligand on the diruthenium complexes and another propargylic alcohol in the catalytic cycle. The reason why only the thiolate-bridged diruthenium complexes promote the ligand exchange step more easily with respect to other monoruthenium complexes in this catalytic reaction should be that one Ru moiety, which is not involved in the allenylidene formation, works as an electron pool or a mobile ligand to another Ru site. The catalytic procedure presented here provides a versatile, direct, and one-step method for propargylic substitution of propargylic alcohols in contrast to the so far well-known stoichiometric and stepwise Nicholas reaction. 相似文献
9.
T Furukawa Y Fujibayashi M Fukunaga A Yokoyama 《Chemical & pharmaceutical bulletin》1990,38(8):2285-2286
To obtain radiogallium labeled immunoglobulin G with a high specific radioactivity for in vitro use, a 67Ga source was purified by extraction from 67Ga-gallium citrate with butyl acetate, and a 67Ga-labeling solution was produced. This solution was then used to label a deferoxamine-immunoglobulin G conjugate. Both a very high specific radioactivity (872 +/- 56 MBq/mg) and a high labeling efficiency (94.0%) were achieved. 相似文献
10.