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141.
13CT1 relaxation times for the different carbons of the sodium dodecyl sulphate chain in micellar systems have been measured, using Gd3+ as a paramagnetic relaxation reagent. The fluorescence decay of ω-(-naphthyl) dodecanoic acid, solubflized in the sodium dodecyl sulphate micelles was obtained in the presence of various amounts of counterion quencher Both series of experiments point to the occurrence of chain folding and to the fact that the terminal group can approach the Stern region of the micelle. 相似文献
142.
Mass spectrometric analysis of ceramide perturbations in brain and fibroblasts of mice and human patients with peroxisomal disorders 总被引:2,自引:0,他引:2
Pettus BJ Baes M Busman M Hannun YA Van Veldhoven PP 《Rapid communications in mass spectrometry : RCM》2004,18(14):1569-1574
In this study, the levels and composition of ceramides in brains of newborn mice lacking peroxisomes (Pex5-/-, Zellweger mice) were analyzed using normal-phase high-performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (HPLC/APCI-MS). Total ceramide compositions were found to be comparable to that of control animals. However, a minor ceramide species, containing hexacosanoic/hexacosenoic acid as the amide fatty acid, was 9-fold increased. Also, in the sphingomyelin-derived ceramides this species was elevated. Subsequent analysis of extracts from fibroblasts of Pex5-/- mice and mice with a defective peroxisomal beta-oxidation (lacking D-specific multifunctional protein 2 (MFP2)), revealed, again, a similar rise in this particular ceramide. Further, this ceramide was elevated in human X-ALD fibroblasts as well. Whether C26:1/0-ceramide is linked to some of the pathology seen in Zellweger syndrome remains to be investigated. However, an increase in this sphingolipid can be considered as a diagnostic criterion for diseases caused by defects in peroxisome biogenesis or peroxisomal beta-oxidation. 相似文献
143.
Lingyan Zhang Ruo Yuan Xiaoqing Huang Yaqing Chai Shurui Cao 《Electrochemistry communications》2004,6(12):1222-1226
A novel potentiometric immunosensor for detection of Japanese B encephalitis vaccine was developed by immobilizing antiserum of Japanese B encephalitis on nano-Au/polymerized o-phenylenediamine (o-PDA) film on the platinum (Pt) electrode. The performance and factors influencing the performance of the resulting immunosensor were studied. The immunosensor showed a specific response to Japanese B encephalitis vaccine in the range 1.1 × 10−8 to 2.0 × 10−6 lgpfu/ml (plaque forming unit) with a detection limit of 6 × 10−9 lgpfu/ml. The correlation coefficient is 0.9986. The incubation time, incubation temperature, pH, reproducibility and stability of the immunosensor were also studied. The present work supplied a promising test method for biological products. 相似文献
144.
Xiao-Bai Sun Pei-Hua Zhao Yang-Jun Xu Li-Mei Sun Mei-Ai Cao Cheng-Shan Yuan 《Chemistry of Natural Compounds》2007,43(5):563-566
Investigation of the roots of Polygonum bistorta L. afforded seven compounds including five triterpenoids, a coumarin, and a steroid, the structures of which were identified
by EIMS, 1H NMR, 13C NMR, DEPT, and HMBC experiments. All the compounds have been isolated from Polygonum genus for the first time.
Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 463–465, September–October, 2007. 相似文献
145.
Perfluoromethyl Element Ligands. XXIX. Preparation and Spectroscopic Investigation of M(CO)4L2 Complexes (M ? Cr, Mo, W; L ? Me2PSMe, Me2PSeMe, (CF3)2PSMe, (CF3)2PSMe) The complexes M(CO)4L2 (see Inhaltsübersicht) have been prepared by the reaction of tetracarbonyl norbornadiene metal compounds M(CO)4NBD with L at room temperature or 35°C, respectively. The cis-complexes formed in the first step undergo rearrangement to trans-isomers at higher temperatures. New compounds have been characterized by analytical and spectroscopic (IR, NMR, MS) methods. 相似文献
146.
H. L. L. M. Van Leengoed N. van der Veen A. A. C. Versteeg R. Ouellet J. E. van Lier W. M. Star 《Photochemistry and photobiology》1993,58(4):575-580
Six sulfonated metallophthalocyanines, chelated with either aluminum or zinc and sulfonated to different degrees, were studied in vivo for their photodynamic activity in a rat skin-fold chamber model. The chamber, located on the back of female WAG/Rij rats, contained a syngeneic mammary carcinoma implanted into a layer of subcutaneous tissue. Twenty-four hours after intravenous administration of 2.5 μmol/kg of one of the dyes, the chambers received a treatment light dose of 600 J/cm2 with monochromatic light of 675 nm at a power density of 100 mW/ cm2. During light delivery and up to a period of 7 days after treatment, vascular effects of tumor and normal tissue were scored. Tumor cell viability was determined by histology and by reimplantation of the chamber contents into the skin of the same animal, either 2 h after treatment or after the 7 day observation period. Vascular effects of both tumor and subcutaneous tissue were strongest with dyes with the lowest degree of sulfonation and decreased with increasing degree of sulfonation. Tumor regrowth did not occur with aluminum phthalocyanine mono- and disulfonate and with zinc phthalocyanine monosulfonate. With the protocol that was used, complete necrosis without recovery was only observed when reimplantation took place at the end of the 7 day follow-up period. Reimplantation 2 h after treatment always resulted in tumor regrowth. At this interval, the presence of viable tumor cells was confirmed histologically. In general tumor tissue vasculature was more susceptible to photodynamic damage than vasculature of the normal tissue. The effect on the circulation of both tumor and normal tissue increased with decreasing degree of sulfonation. Based on this study, the photodynamic effects using the six sulfonated metallophthalocyanines on the vasculature can be ranked from high to low as: AlPcS2= ZnPcS1 > AIPcS1 > AIPcS4 > ZnPcS2 > ZnPcS4. 相似文献
147.
The I-E response of the liquid membrane of the calcium selective electrode is studied under constant or linearly varying current and voltage. An increase in the membrane resistance, recorded when an electrical current crosses the membrane, is due to the outflow of Cl? ions initially present in the membrane. When calcium ions are replaced by alkaline ions inside the membrane at constant current, the decrease of the membrane resistance due to an ion exchange is in agreement with the conductivity measurements (Part II). When the applied voltage is imposed besides the ion exchange one must take into account the interfacial overpotential to explain the important rectification effect observed. The interfacial transfer constant rate of alkaline ions seems greater than that of Ca2+ ion. 相似文献
148.
Here we report the formation and spectroscopic properties of cadmium sulfide (CdS) nanocrystal systems: individual nanocrystal and CdS aggregates. The optical absorption and luminescence spectra of the aggregated CdS nanocrystals and individual nanocrystal show exciton aggregate and individual exciton characteristics. Although it is not Bose-Einstein condensation, such aggregated quantum dots (QDs) seem to supply us opportunity to study the interactions and condensation of excitons in multi-QDs system, not in the separated QDs system. 相似文献
149.
Pozzoli L Bolzacchini E Van Dingenen R Hjiorth J Dentener F Perrone G Rindone B Librando V 《Annali di chimica》2003,93(4):447-456
The model BAGS (Boxmodel for Aerosol and Gasphase Simulations) has been developed. It is composed of two major modules: the first one describes the system of the chemical reactions in the gaseous phase, the second one calculates the aerosol chemical composition and the dimensional distribution of the particles. The boxmodel has been developed with the introduction of new chemical and physical processes, not previously included, in particular the formation of Secondary Organic Aerosol. The other implemented processes are a module for the dynamic of the particle population, nucleation, coagulation and dry deposition. The last phase of the work has been a check of the BAGS capabilities by a series of tests, that have permitted to compare it with other models (MAPS and MADM). The tests in particular have concerned the aerosol water content prediction, the photochemistry, the condensation of the inorganic compounds and the formation of Secondary Organic Aerosol. 相似文献
150.
The controlled synthesis of SrCO3 nanostructures with different morphologies, such as rodlike, whiskerlike, ellipsoidlike, and spherelike, were successfully achieved by the cationic surfactant-CTAB-microemulsion-mediated solvothermal method. Various comparison experiments showed that fundamental experimental parameters, such as the molar ratio of H2O to CTAB and the concentration of reactants, played important roles in the morphological control of SrCO3 nanostructures. A lower molar ratio of H2O to CTAB favors rodlike products, whereas a higher molar ratio generally leads to the formation of spherical products. A rational mechanism based on fusion, aggregate, and coalescence of microemulsion droplets is proposed for the selective formation of various morphologies. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and field-emission scanning electron microscope (FE-SEM) were used to characterize the products. 相似文献