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991.
Olusegun S. Ajala Andrew M. PiggottFabien Plisson Zeinab KhalilXiao-cong Huang Sunday A. AdesegunHerbert A.B. Coker Robert J. Capon 《Tetrahedron letters》2011,52(52):7125-7127
Chemical investigations into samples of Hunteria umbellata (K. Schum) collected in Osun State, Nigeria, led to the discovery of a new indole alkaloid, ikirydinium A, featuring an unprecedented 3-alkylpyridinium-indole-2-carboxylate scaffold. Ikirydinium A was found to exhibit antimicrobial activity (IC50 0.6 μM) against Bacillus subtilis ATCC 6051. The involvement of a common intermediate in the biosynthesis of ikirydinium A and vinblastine is hypothesized. 相似文献
992.
The synthesis of a generation 5 (G5) poly(amidoamine) (PAMAM) dendrimer platform having cyclooctyne ligands that were subsequently be used for a copper-free Huisgen 1,3-dipolar cycloaddition (click reaction) with azido modified methotrexate is described. The G5 PAMAM dendrimer was first partially (70%) acetylated and then coupled with 20 cyclooctyne ligands through amide bonds. The remaining primary amine groups on the dendrimer surface were neutralized by acetylation. The platform was then ‘clicked’ with different numbers (5, 10, and 17) of γ-azido functionalized methotrexate. The copper-free click reactions were stoichiometric with excellent yields. 相似文献
993.
994.
The reaction of the thiocarbamoyl‐molybdenum complex [Mo(CO)2(η2‐SCNMe2)(PPh3)2Cl] 1 , with EtOCS2K and C4H8NCS2NH4 in dichloromethane at room temperature yielded the seven coordinated ethyldithiocarbonate thiocarbamoyl‐molybdenum complex [Mo(CO)2(η2‐S2COEt)(η2‐SCNMe2)(PPh3)] 2 , and the dithiocarbamate thiocarbamoyl‐molybdenum complex [Mo(CO)2(η2‐S2CNC4H8)(η2‐SCNMe2)(PPh3)] 3 . The geometry around the metal atom of compounds 2 and 3 are capped octahedrons as revealed by X‐ray diffraction analyses. The thiocarbamoyl and ethyldithiocarbonate or pyrrolidinyldithiocarbamate ligands coordinate to the molybdenum metal center through the carbon and sulfur and two sulfur atoms, respectively. Structure parameters, NMR, IR and Mass spectra are in agreement with the crystal chemistry of the two compounds. 相似文献
995.
A new iridoid, torrilliolide ( 1 ), and a new pyridine alkaloid, torricelline ( 2 ), were isolated from the stem barks of Torricellia tiliifolia. Their structures were determined by analysis of their spectroscopic data. Both compounds exhibited cytotoxicity against Spodoptera litura cell line. 相似文献
996.
Ping‐Tsung Huang Cheng‐Wei Chou Mei‐Ying Chang Wen‐Yao Huang Chih‐Chien Lee Yu‐Kai Han Shun‐Wei Liu 《中国化学会会志》2011,58(3):326-331
The performance of a blue polymer light‐emitting diodes (PLED) was significantly improved by doping a controlled amount (<1%) of a hole transport molecule N,N′‐bis‐(1‐naphthyl)‐N,N′‐diphenyl‐1,1′‐biphenyl‐4,4″‐diamine (NPB) into the emitting layer. Hole carrier mobility of the blue emitting polymer, BP105 (trade name of The Dow Chemicals Co.), increased from 5.27 × 10‐7 cm‐2/Vs of the pristine BP105 to 1.80 × 10‐6 cm‐2/Vs with the addition of 1% NPB in BP105. The enhanced carrier mobility greatly promoted performance of a blue PLED device with a device structure of ITO/PEDOT:PSS/BP105+x% NPB/LiF/Ca/Al. Luminance increased from 573 cd/m2 to 2,720 cd/m2 at 6V and efficiency increased from 1.1 lm/W to 1.6 lm/W at 1,000 cd/m2 with 1% NPB in BP105. The most important improvement was an increase in the lifetime of the blue device from 80 to 120 hours at an initial luminance of 400 cd/m2. We found that by choosing the appropriate dopant with good energy alignment and controlled dopant concentration, the performance of a blue PLED device could be greatly improved. 相似文献
997.
New mesoporous organic?Cinorganic spheres were prepared by one step co-condensation of trialkoxysilylated camphorsulfonamide (CSA) and 1,2-bis(triethoxysilyl)ethane (BTSE) using octadecyltrimethylammonium chloride (C18TMACl) as template and ethanol as co-solvent in basic medium. The materials have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), nitrogen sorption measurement, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and elemental analysis (EA). Then the mesoporous organic?Cinorganic spheres were demonstrated to be novel packing materials for potential application in the normal-phase high performance liquid chromatography (HPLC). 相似文献
998.
Ziming Chen Hongbo Huang Yuchan Chen Zhongwen Wang Junying Ma Bo Wang Weimin Zhang Changsheng Zhang Jianhua Ju 《Helvetica chimica acta》2011,94(9):1671-1676
Two new cytochalasins, 18‐deoxycytochalasin Q ( 1 ) and 21‐O‐deacetylcytochalasin Q ( 2 ), together with four known analogues, cytochalasin Q ( 3 ), 19,20‐epoxycytochalasin Q ( 4 ), 21‐O‐deacetyl‐19,20‐epoxycytochalasin Q ( 5 ), and cytochalasin D ( 6 ), were isolated from the fungus Xylaria sp. SCSIO156 originated from the South China Sea marine sediment. The structures of 1 and 2 were elucidated by MS and 1D‐ and 2D‐NMR data analyses, and comparison with known compounds. The known compounds 3 – 6 were identified by comparison of their MS and NMR data with those reported in the literature. In the in vitro antitumor assay, compounds 2 – 6 showed mild cytotoxicity against three tumor cell lines (MCF‐7, SF‐268, and NCI‐H460). 相似文献
999.
New crown ether carrying two fluorionophores of cis‐dibenzothiazolyldibenzo‐24‐crown‐8 was synthesized from cis‐diformyldibenzo‐24‐crown‐8 and 2‐aminobenzenethiol. The binding behavior and the optical properties of the crown ether were examined through UV‐visible spectroscopy and fluorescence spectroscopy. When complexed with Na+, K+, Rb+, and Cs+ ions, it led to intramolecular charge transfer and caused the changes of the fluorescence spectra. The protonation of the crown ether was also studied. With protonation using CF3COOH, the absorption bands and the fluorescence spectroscopy changed, the maximal fluorescence wavelengths red shifted and the fluorescence intensity with the maximum at 433 nm enhanced strongly. J. Heterocyclic Chem., (2011). 相似文献
1000.
Phase diagram, crystal chemistry and thermoelectric properties of compounds in the Ca-Co-Zn-O system
W. Wong-Ng T. Luo W.H. Tang Q. Huang S. Chattopadhyay T. Tritt 《Journal of solid state chemistry》2011,184(8):2159-2166
In the Ca-Co-Zn-O system, we have determined the tie-line relationships and the thermoelectric properties, solid solution limits, and structures of two low-dimensional cobaltite series, Ca3(Co, Zn)4O9−z and Ca3(Co,Zn)2O6−z at 885 °C in air. In Ca3(Co,Zn)4O9−z, which has a misfit layered structure, Zn was found to substitute in the Co site to a limit of Ca3(Co3.8Zn0.2)O9−z. The compound Ca3(Co,Zn)2O6−z (n=1 member of the homologous series, Can+2(Co,Zn)n(Co,Zn)′O3n+3−z) consists of one-dimensional parallel (Co,Zn)2O66− chains that are built from successive alternating face-sharing (Co,Zn)O6 trigonal prisms and ‘n’ units of (Co,Zn)O6 octahedra along the hexagonal c-axis. Zn substitutes in the Co site of Ca3Co2O6 to a small amount of approximately Ca3(Co1.95Zn0.05)O6−z. In the ZnO-CoOz system, Zn substitutes in the tetrahedral Co site of Co3O4 to the maximum amount of (Co2.49Zn0.51)O4−z and Co substitutes in the Zn site of ZnO to (Zn0.94Co0.06)O. The crystal structures of (Co2.7Zn0.3)O4−z, (Zn0.94Co0.06)O, and Ca3(Co1.95 Zn0.05)O6−z are described. Despite the Ca3(Co, Zn)2O6−z series having reasonably high Seebeck coefficients and relatively low thermal conductivity, the electrical resistivity values of its members are too high to achieve high figure of merit, ZT. 相似文献