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We examined the utility of a monolithic capillary column in the analysis of pyridylaminated oligosaccharides. Fluorescence detection and mass spectrometry were used to monitor a series of oligosaccharides. Although the total-ion chromatogram appeared similar to that obtained with fluorescence detection, the sensitivity of this technique was limited, especially in the case of smaller oligosaccharides. This limitation was overcome by applying selected ion current monitoring. Further, the capillary column also exhibited good reproducibility. We showed that the retention times obtained by using the monolithic capillary column could be converted into the standard data to enable comparison of the experimental data with the existing data. Furthermore, our studies revealed an important difference in the separation profile, i.e., the monolithic capillary column could resolve smaller oligosaccharides to a greater extent. 相似文献
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Takeshi Kumazawa Koichi Saeki Isao Yanagisawa Seisaku Uchigasaki Chika Hasegawa Hiroshi Seno Osamu Suzuki Keizo Sato 《Analytical and bioanalytical chemistry》2009,394(4):1161-1170
This paper describes a fully automated on-line method combining in-tube solid-phase microextraction (SPME) in which sample
clean-up and enrichment are conducted through an open tubular fused-silica capillary column and high-performance liquid chromatography
(HPLC)/tandem mass spectrometry (MS/MS) detection for the determination of six butyrophenone derivatives (moperone, floropipamide,
haloperidol, spiroperidol, bromperidol, and pimozide) in human plasma samples. The six butyrophenones were extracted by repeatedly
aspirating and dispensing plasma sample solutions on a DB-17 capillary column (60 cm × 0.32 mm i.d., film thickness 0.25 μm).
The analytes retained on the inner surface of the capillary column were then eluted into an acetonitrile-rich mobile phase
using a gradient separation technique. Extraction efficiencies ranged from 12.7% to 31.8% for moperone, spiroperidol, and
pimozide, and from 1.08% to 4.86% for floropipamide, haloperidol, and bromperidol. The regression equations for all compounds
showed excellent linearity, ranging from 0.05 to 50 ng/0.1 mL of plasma, except for moperone and spiroperidol (0.01 to 50 ng/0.1 mL).
The limits of detection and quantification in plasma for each drug were 0.03–0.2 and 0.1–0.5 ng/mL, respectively. The intra-
and inter-day coefficients of variation for all compounds in plasma were not greater than 13.7%. 相似文献
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The Ni-catalyzed cross-coupling of 2-bromo-3,3,3-trifluoropropene and aryl Grignard reagents was investigated. When NiCl2(PPh3)2 was used as a catalyst, the highest yield of α-trifluoromethylstyrene (89%) from 2-bromo-3,3,3-trifluoropropene and PhMgBr was obtained in 1,3-dimethyl-2-imidazolidinone at 50 °C for 30 min. Various α-trifluoromethylstyrene derivatives could be produced in satisfactory yields by NiCl2(PPh3)2-catalyzed coupling using aryl Grignard reagents. 相似文献
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Xiulan Hu Xin Zhang Xiaodong Shen Hongtao Li Osamu Takai Nagahiro Saito 《Plasma Chemistry and Plasma Processing》2014,34(5):1129-1139
Fiber-shaped cupric oxide (CuO) nanoparticles and flower-shaped ZnO nanoparticles were facilely synthesized by plasma-induced technique directly from copper and zinc electrode pair in water, respectively. The phase composition, morphologies and optical property of nanoparticles have been investigated by energy dispersive X-ray analysis, X-ray powder diffraction, transmission electron microscopy and UV–vis. The in situ analysis by an optical emission spectroscopy clarified the formation mechanism. Plasma was generated from the discharge between a metal electrode pair in water by a pulse direct current power. CuO and ZnO nanoparticles were synthesized via almost the same formation mechanism, which were prepared via the rapid energetic radicals’ bombardment to electrodes’ surface, atom vapour diffusion, plasma expansion, solution medium condensation, and in situ oxygen reaction and further growth. This novel plasma-induced technique will become a potential application in nanomaterials synthesis. 相似文献
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Osamu Yamashita Kouji Satou Hirotaka Odahara Shoichi Tomiyoshi 《Journal of Physics and Chemistry of Solids》2005,66(7):1287-1293
The p-type (Bi0.25Sb0.75)2Te3 doped with 3-12 wt% excess Te alone and n-type Bi2(Te0.94Se0.06)3 codoped with 0.017-0.026 wt% Te and 0.068-0.102 wt% I were prepared by the Bridgman method, to produce intentionally polycrystalline. Some of the as-grown specimens were annealed, in order to prepare specimens with much different ρ. These polycrystalline specimens have almost the same degree of alignment of the c plane parallel to the freezing direction. The electrical rersistivity ρ and thermal conductivity κ were measured at 298 K along the freezing direction and κ was plotted as a function of ρ. As a result, the lattice components κph obtained by subtracting the electronic component κel from the observed κ were found to decrease almost linearly with a decrease of ρ in both p- and n-type specimens, where κel was calculated using Wiedemann-Franz law. This tendency is consistent with the conventional result that κph becomes negligible small in metals. The significant decrease in κph with decrease in ρ is considered to be caused predominantly by the phonon scattering due to dopants. The relationship between κph and ρ was first clarified in the intermediate region between the metal and insulator. 相似文献
59.
Yutaka Miura Toshifumi Satoh Atsushi Narumi Osamu Nishizawa Yoshio Okamoto Toyoji Kakuchi 《Journal of polymer science. Part A, Polymer chemistry》2006,44(4):1436-1446
The copper‐mediated atom transfer radical polymerization of methyl methacrylate (MMA) in 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) was studied to simultaneously control the molecular weight and tacticity. The polymerization using tris[2‐(dimethylamino)ethyl]amine (Me6TREN) as a ligand was performed even at ?78°C with a number‐average molecular weight (Mn) of 13,400 and a polydispersity (weight‐average molecular weight/number‐average molecular weight) of 1.31, although the measured Mn's were much higher than the theoretical ones. The addition of copper(II) bromide (CuBr2) apparently affected the early stage of the polymerization; that is, the polymerization could proceed in a controlled manner under the condition of [MMA]0/[methyl α‐bromoisobutyrate]0/[CuBr]0/[CuBr2]0/[Me6TREN]0 = 200/1/1/0.2/1.2 at ?20°C with an MMA/HFIP ratio of 1/4 (v/v). For the field desorption mass spectrum of CuIBr/Me6TREN in HFIP, there were [Cu(Me6TREN)Br]+ and [Cu(Me6TREN)OCH(CF3)2]+, indicating that HFIP should coordinate to the CuI/Me6TREN complex. The syndiotacticity of the obtained poly(methyl methacrylate)s increased with the decreasing polymerization temperature; the racemo content was 84% for ?78°C, 77% for ?30°C, 75% for ?20°C, and 63% for 30°C. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1436–1446, 2006 相似文献
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