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81.
溶胶-凝胶法固定胆固醇氧化酶偶联普鲁士蓝化学修饰电极的研究 总被引:9,自引:0,他引:9
用溶胶-凝胶法将胆固醇氧化酶固定在普鲁士蓝修饰的玻碳电极表面,制成了一种新型胆固醇传感器,实现了低电位下对胆固醇的间接测定,胆固醇的测定范围伏安法为5×10-7~8×10-5mol/L,安培法为5×10-6~5×10-4mol/L.伏安法检出限为1.2×10-7mol/L,是目前所见灵敏度最高的胆固醇传感器之一,该传感器对胆固醇的测定可避免常规电化学传感器测定中由于样品中大量存在的易氧化物质所带来的干扰,该传感器的寿命长,使用次数在300次以上. 相似文献
82.
以18-冠-6和4-碘-苯铵盐,二苯并30-冠-10和3-氟-4-氯-苯铵盐为超分子阳离子构建单元,分别引入到Keggin型[SMo12O40]2-中,使用H管扩散法和溶剂挥发法合成了无机-有机杂化材料[(4-I-Anis)([18]crown-6)]2[SMo12O40]·CH3CN(1)和[(3-F-4-Cl-Anis)2(DB[30]crown-10)][SMo12O40]·2CH3CN(2)(4-I-Anis=4-碘-苯铵盐;3-F-4-Cl-Anis=3-氟-4-甲基苯铵盐;DB[30]crown-10=二苯并30-冠-10)。通过红外光谱、元素分析、热重分析、固态漫反射光谱和X射线单晶结构分析对化合物进行了表征。结构分析表明,晶体1和2通过非共价键自组装作用构建而成,冠醚基超分子阳离子是通过N-H…O氢键作用形成。晶体1中,在bc平面,每个[SMo12O40]2-多酸阴离子被6个超分子阳离子(4-I-Anis)([18]crown-6)围绕,形成六边形的结构;晶体2中,在bc平面,每个[SMo12O40]2-多酸阴离子被4个大的超分子阳离子(3-F-4-Cl-Anis)2(DB[30]crown-10)围绕,形成四边形的结构。热重分析表明,氢键在维持晶体1和2的稳定性上起着主要的作用。固态漫反射光谱表明,[SMo12O40]2-和冠醚基超分子阳离子之间存在电荷转移作用。 相似文献
83.
Lorne Tallet Emilie Frisch Mgane Bornerie Claire Medemblik Benoît Frisch Philippe Lavalle Gilles Guichard Cline Douat Antoine Kichler 《Molecules (Basel, Switzerland)》2022,27(5)
There is an urgent need to develop new therapeutic strategies to fight the emergence of multidrug resistant bacteria. Many antimicrobial peptides (AMPs) have been identified and characterized, but clinical translation has been limited partly due to their structural instability and degradability in physiological environments. The use of unnatural backbones leading to foldamers can generate peptidomimetics with improved properties and conformational stability. We recently reported the successful design of urea-based eukaryotic cell-penetrating foldamers (CPFs). Since cell-penetrating peptides and AMPs generally share many common features, we prepared new sequences derived from CPFs by varying the distribution of histidine- and arginine-type residues at the surface of the oligourea helix, and evaluated their activity on both Gram-positive and Gram-negative bacteria as well as on fungi. In addition, we prepared and tested new amphiphilic block cofoldamers consisting of an oligourea and a peptide segment whereby polar and charged residues are located in the peptide segment and more hydrophobic residues in the oligourea segment. Several foldamer sequences were found to display potent antibacterial activities even in the presence of 50% serum. Importantly, we show that these urea-based foldamers also possess promising antifungal properties. 相似文献
84.
制备了脱乙酰基魔芋葡甘聚糖(d-KGM)的溶胶-凝胶,用红外光谱表征了其脱乙酰基前后的结构转化.探讨了d-KGM溶胶-凝胶的制备条件对其成膜性能及酶固定化的影响.在此基础上将d-KGM用于电极表面葡萄糖氧化酶的固定,制备了相应的葡萄糖传感器,并对传感器的工作条件进行了优化.所制备的传感器灵敏度为240 nA/mmol/L,线性范围为0.1~8 mmol/L,表观米氏常数KM为19.6 mmol/L,稳定性好,寿命长.实验结果表明d-KGM是一种可用于生物传感器中酶固定化的优良材料. 相似文献
85.
DING Ya-mei YUAN Xiao-yan ZHAO Jin GUO Wan-chun WANG Xiu-kui 《高等学校化学研究》2007,23(3):366-369
Ultrafine apatite fibers were prepared by electrospinning of sol-gel precursor/poly( vinyl pyrrolidone) (PVP) solutions followed by subsequent calcination. The as-electrospun and calcinated fibers were observed under a scanning electron microscope and an optical polarizing microscope. Results show that the morphology and the diameter of as-electrospun fibers strongly depend on the viscosity and the surface tension of sol-gel precursor/PVP solutions. After calcination, the smooth as-electrospun fibers shrink and the fiber diameter decreases because of the removal of the polymer. The chemical evolution upon the transformation of the precursor from a gel to the final apatite fibers was investigated by thermogravimetric-differenfial thermal analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. It is thus suggested that the crystalline structure of the calcined fibers is largely influenced by the calcination temperature. After being calcined at 600 ℃, the apatite fibers with a diameter of about 280 nm containing β-tricalcium phosphate were obtained. 相似文献
86.
Structural, morphological and optical properties of rare earth ions (RE3+=Sm3+ or Dy3+) activated Ca3Ga2Si3O12 (CaGaSi) phosphors synthesized by the sol-gel method are reported. XRD results confirmed the cubic phase structure of RE3+:CaGaSi phosphors. From the SEM images of RE3+:CaGaSi phosphors, it is observed that the particles are agglomerated. Photoluminescence spectra of Sm3+:CaGaSi phosphors have shown bright orange red emission at 598 nm (4G5/2→6H7/2) with an excitation wavelength of λexci=401 nm. In the case of Dy3+:CaGaSi phosphors bright yellow emission has been observed at 574 nm (4F9/2→ 6H13/2) with λexci=451 nm. From the PL spectral results, the rare earth ion concentration of CaGaSi phosphors is optimized. 相似文献
87.
" 在Pt/Ti/SiO2/Si基片上用溶胶-凝胶法与快速退火工艺制备了300 nm厚的锆钛酸铅Pb(Zr0:95Ti0:05)O3 (PZT95/5)反铁电薄膜.结果显示600~700 ℃晶化处理的钙钛矿PZT95/5薄膜具有高度(111)取向生长特性.薄膜的电性能测量采用金属-铁电-金属电容器结构.在20 V电压作用下,600~700 ℃晶化处理的PZT95/5薄膜显示出饱和电滞回线.在1 kHz下,600、650和700 ℃晶化的薄膜介电常数与损耗分别为519与0.028、677与0.029、987 相似文献
88.
By using metal nitrates as starting materials and citric acid as complexing agent, GdCaAl3O7:Eu3+ and GdCaAl3O7:Tb3+ powder phosphors were prepared by a citrate-gel method. Thermal analysis (TG-DTG), X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM), photoluminescence excitation and emission, as well as kinetic decays were employed to characterize the resulting samples. The results of the XRD indicated the precursor samples began to crystallize at 800 °C and the crystallinity increased with elevation the annealing temperature. TEM images showed that the phosphor particles were basically of spherical shape, with good dispersion about a particle size of around 40-70 nm. Upon excitation with UV irradiation, it is shown that there is a strong emission at around 617 nm corresponding to the forced electric dipole 5D0-7F2 transition of Eu3+, and at around 543 nm corresponding to the 5D4-7F5 transition of Tb3+. The dependence of photoluminescence intensity on Eu3+ (or Tb3+) concentration and annealing temperature were also studied in detail. 相似文献
89.
D. Milivojevi?B. Babi?-Stoji? V. Jokanovi?Z. Jagli?i? D. Makovec 《Journal of magnetism and magnetic materials》2011,323(6):805-812
Samples of Mn-oxide nanoparticles dispersed in an amorphous SiO2 matrix with manganese concentration 0.7 and 3 at% have been synthesized by a sol-gel method. Transmission electron microscopy analysis has shown that the samples contain agglomerates of amorphous silica particles 10-20 nm in size. In silica matrix two types of Mn-rich particles are dispersed, smaller nanoparticles with dimensions between 3 and 10 nm, and larger crystalline areas consisting of aggregates of the smaller nanoparticles. High-temperature magnetic susceptibility study reveals that dominant magnetic phase at higher temperatures is λ-MnO2. At temperatures below TC=43 K strong ferrimagnetism originating from the minor Mn3O4 phase masks the relatively weak magnetism of λ-MnO2 with antiferromagnetic interactions. Magnetic field dependence of the maximum in the zero-field-cooled magnetization for both the samples in the vicinity of 40 K, and a frequency shift of the real component of the ac magnetic susceptibility in the sample with 3 at% Mn suggest that the magnetic moments of the smaller Mn3O4 nanoparticles with dimensions below 10 nm are exposed to thermally activated blocking process just below the Curie temperature TC. Appearance of a maximum in the zero-field-cooled magnetization for both the samples below 10 K indicates possible spin glass freezing of the magnetic moments at low temperatures which might occur in the geometrically frustrated Mn sublattice of the λ-MnO2 crystal structure. 相似文献
90.