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161.
J. Leitner M. Hampl K. Ri
ka D. Sedmidubský P. Svoboda J. Vejpravov 《Thermochimica Acta》2006,450(1-2):105-109
The heat capacities and enthalpy increments of strontium bismuth niobate SrBi2Nb2O9 (SBN) and strontium bismuth tantalate SrBi2Ta2O9 (SBT) were measured by the relaxation method (2–150 K), Calvet-type heat-conduction calorimetry (305–570 K) and drop calorimetry (773–1373 K). The temperature dependences of non-transition heat capacities in the form Cpm = 324.47 + 0.06371T − 5.0755 × 106/T2 J K−1 mol−1 (298–1400 K) and Cpm = 320.22 + 0.06451T − 4.7001 × 106/T2 J K−1 mol−1 (298–1400 K) were derived for SBN and SBT, respectively, by the least-squares method from the experimental data. Furthermore, the standard molar entropies at 298.15 K Sm°(SBN)=327.15±0.80 and Sm°(SBT)=339.23±0.72 J K−1 mol−1 were evaluated from the low-temperature heat capacity measurements. 相似文献
162.
Karel Cizek Jiri Barek Jan Fischer Karolina Peckova Jiri Zima 《Electroanalysis》2007,19(12):1295-1299
The voltammetric behavior of 3‐nitrofluoranthene and 3‐aminofluoranthene was investigated in mixed methanol‐water solutions by differential pulse voltammetry (DPV) at boron doped diamond thin‐film electrode (BDDE). Optimum conditions have been found for determination of 3‐nitrofluoranthene in the concentration range of 2×10?8–1×10?6 mol L?1, and for determination 3‐aminofluorathnene in the concentration range of 2×10?7–1×10?5 mol L?1, respectively. Limits of determination were 3×10?8 mol L?1 (3‐nitrofluoranthene) and 2×10?7 mol L?1 (3‐aminofluoranthene). 相似文献
163.
Nobilis M Kopecký J Kvetina J Chládek J Svoboda Z Vorísek V Perlík F Pour M Kunes J 《Journal of chromatography. A》2002,949(1-2):11-22
Simultaneous HPLC determination of the analgetic agent tramadol, its major pharmacodynamically active metabolite (O-desmethyltramadol) in human plasma is described. Simple methods for the preparation of the standard of the above-mentioned tramadol metabolite and N1,N1-dimethylsulfanilamide (used as the internal standard) are also presented. The analytical procedure involved a simple liquid-liquid extraction of the analytes from the plasma under the conditions described previously. HPLC analysis was performed on a 250x4 mm chromatographic column with LiChrospher 60 RP-selectB 5-microm (Merck) and consists of an analytical period where the mobile phase acetonitrile-0.01 M phosphate buffer, pH 2.8 (3:7, v/v) was used, and of a subsequent wash-out period where the plasmatic ballast compounds were eluted from the column using acetonitrile-ultra-high-quality water (8:2, v/v). The whole analysis, including the equilibration preceding the initial analytical conditions lasted 19 min. Fluorescence detection (lambda(ex) 202 nm/lambda(em) 296 nm for tramadol and its metabolite, lambda(ex) 264 nm/lambda(em) 344 nm for N1,N1-dimethylsulfanilamide) was used. The validated analytical method was applied to pharmacokinetic studies of tramadol in human volunteers. 相似文献
164.
Haines TJ Bionta RM Blewitt G Bratton CB Casper D Claus R Cortez BG Errede S Foster GW Gajewski W Ganezer KS Goldhaber M Jones TW Kielczewska D Kropp WR Learned JG Lehmann E LoSecco JM Matthews J Park HS Price LR Reines F Schultz J Seidel S Shumard E Sinclair D Sobel HW Stone JL Sulak L Svoboda R van der Velde JC Wuest C 《Physical review letters》1986,57(16):1986-1989
165.
An empirical force-field for carbenium ions has been incorporated in Allinger's MM2 programme. Structural parameters of secondary carbenium ions calculated by this method are compared with those obtained with Schleyer's BIGSTRN calculations. The strain changes occurring upon solvolysis of secondary p-toluenesulfonates are evaluated by means of this force-field and correlated with the rate constants for solvolysis. The equation for correlation of acetolysis, relative to cyclohexyl p-toluenesulfonate, of 28 kc substrates is ΔG = 0.67 ΔEst - 0.20 (r = 0.958). 相似文献
166.
M. Matucha und V. Svoboda 《Fresenius' Journal of Analytical Chemistry》1966,220(4):279-282
Zusammenfassung Zur Kontrolle von Bengalrotsorten verschiedener Herkunft, besonders von solchen, die als Rohstoffe für mit radioaktivem Jod markierte medizinische Präparate verwendet werden, wird die chromatographische Analyse nach vorhergehender Jodierung vorgeschlagen. Man kann die im Gehalt an Chlor unterschiedlichen Stoffe bestimmen und so die Arten Bengalrot zwar langsam, aber ohne große Mühe bewerten.
Summary For analytical control of Rose Bengale—especially when used as raw material for medicinal preparations labelled by radioactive iodine—paper-chromatographic analysis after preceding iodination is proposed. It is possible to determine the substances differing in chlorine content and to classify the Rose Bengale samples in an easy and simple, although somewhat lengthy way.相似文献
167.
Ulrich Burger Yves G. Mentha Patricia Millasson Pierre-Andr Lottaz Jiri Mareda 《Helvetica chimica acta》1989,72(8):1722-1728
Starting from dibenzo[a, c]cyclooctene (4) and 4-methyl-3H-1,2,4-triazol-3,5(4H)-dione (MTAD), the strained skeleton of the title azo compound 1 is assembled in a tandem photo-Diels-Alder addition/di-π-methane rearrangement sequence. The synthesis is completed by a stepwise hydrolytic oxidation of the ensuing triazolidine-dione 2 with nickel peroxide. Thermolysis of 1 in benzene solution is shown to be governed by an initial 1,3-dipolar cycloreversion which leads, via an intermediate diazo compound 11 , to cyclobuta[1]phenanthrene 8 and two further carbene-derived C16H12 products. Photolysis of 1 at 350 nm leads in modest yield (12%), via a diazenyl diradical, to an unstable bridged bicyclobutane 10 (dibenzooctavalene). MNDO calculations suggest the latter to have a rapidly inverting, twisted structure of C2 symmetry. 相似文献
168.
K. Svoboda J. Lezama J. Tendilla F. Melichar M. Tympl 《Journal of Radioanalytical and Nuclear Chemistry》1985,96(4):405-412
A new concept of prefabricated99mTc generator has been experimentally tested as a possible procedure for local production of99mTc for medical purposes by means of the ININ-Salazar /Mexico/ Triga-Mark III reactor working at 1 MW.Temporarily at ININ as IAEA expert. 相似文献
169.
170.
Osvaldo Goscinski Jiri Müller Enrique Poulain Hans Siegbahn 《Chemical physics letters》1978,55(3):407-412
Ab initio calculations within the Hartree-Fock formation have been carried out on potential energy surfaces of the ground and the F1s hole states of CH3F and CF4 in order to investigate linewidths of their ESCA spectra. The calculations show that potential energy surfaces of both hole states have dissociative character and can be approximated by straight lines in the region of interest. A simple formula for the ESCA fwhm linewidth is derived which yields results in good agreement with experiment. Theoretically derived relaxation and Koopmans' energies have been investigated as a function of geometry. 相似文献