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991.
AbstractEffective extraction of phyto-biomolecules insures retaining maximum functionality along with higher recovery. In this study, ultrasound-solvent assisted extraction (USAE) was employed for optimal extraction of phyto-biomolecules from Sesamum indicum (sesame) leaves using the approach of Response Surface Methodology (RSM). The optimized condition of 200?W power, 59% methanol concentration with 1:14?g/mL solid–liquid ratio and 15?min of extraction time yielded 367.39?±?1.85?mg GAE/100?g of total phenolic content, 96.72?±?3.27% of free radical scavenging activity and 81.20?±?2.87% of iron chelating activity respectively. The extract consist of essential phytocomponents like gallic acid, chlorogenic acid, and quercetin with lipid peroxidation activities of >50% over incubation time of 48?h. Also, showed antimicrobial activity against various Gram’s negative and positive food borne pathogens. The results of this study implied the importance of USAE for effective and optimum recovery of phyto-biomolecules from Sesame leaves with retained functional properties. 相似文献
992.
Headspace solid‐phase microextraction is a solvent‐free sample preparation technique that is based on the equilibrium among a three‐phase system, i.e., sample‐headspace‐fiber. A compromise between sensitivity and extraction time is usually needed to optimize the sample throughput, especially when a large number of samples are analyzed, as usually the case in cross‐samples studies. This work explores the capability of multiple‐cumulative trapping solid‐phase microextraction on the characterization of the aroma profiling of olive oils, exploiting the automation capability of a novel headspace autosampler. It was shown that multiple‐cumulative solid‐phase microextraction has the potential to improve the overall sensitivity and burst the level of information for cross‐sample studies by using cumulative shorter extraction times. 相似文献
993.
Yinan Guo Wei Wei Ying Zhang Yuanyuan Dai Weiping Wang Aijun Wang 《Journal of separation science》2020,43(17):3499-3508
An aptamer (Apt) functionalized magnetic material was prepared by covalently link Apt to Fe3O4/graphene oxide (Fe3O4/GO) composite by 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide hydrochloride and N‐hydroxysuccinimide, and then characterized by FTIR spectroscopy, X‐ray diffraction, and vibration sample magnetometry. The obtained composite of Fe3O4/GO/Apt was employed as magnetic solid‐phase extraction adsorbent for the selective preconcentration of sulfadimethoxine prior to analysis by high‐performance liquid chromatography. Under the optimal conditions (sample pH of 4.0, sorbent dosage of 20 mg, extraction time of 3 h, and methanol‐5% acetic acid solution as eluent), a good linear relationship was obtained between the peak area and concentration of sulfadimethoxine in the range of 5.0 to 1500.0 µg/L with correlation coefficient of 0.9997. The limit of detection (S/N = 3) was 3.3 µg/L. The developed method was successfully applied to the analysis of sulfadimethoxine in milk with recoveries in the range of 75.9‐92.3% and relative standard deviations less than 8.1%. The adsorption mechanism of Fe3O4/GO/Apt toward sulfadimethoxine was studied through the adsorption kinetics and adsorption isotherms, and the results show that the adsorption process fits well with the pseudo‐second‐order kinetic model and the adsorbate on Fe3O4/GO/Apt is multilayer and heterogeneous. 相似文献
994.
Zeinab Akbarzadeh 《Green Chemistry Letters and Reviews》2020,13(2):141-154
ABSTRACT A novel mesoporous Al-SBA-15 modified by N,N'-(1,2-phenylene)bis(2-aminobenzamide) dichloro cobalt has been prepared and applied as a reusable catalyst in the 3-cinnamoyl coumarins synthesis via three-component reaction between benzaldehydes, salicylaldehydes and ethyl acetoacetate by the assist of ultrasonic irradiation. By using of the nanocatalyst and also ultrasound irradiation, the easiness and velocity of the abovementioned reaction were enhanced and an environment friendly condition was provided to synthesis of various 3-cinnamoyl coumarin compounds. The properties and structure of nanocatalyst have been specified by methods including powder X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), nitrogen adsorption–desorption analysis and scanning electronic microscopy (SEM). Superiority of this novel and viable method is due to mild reaction condition, short reaction times, high yields of 3-cinnamoyl coumarins, environmentally benign, recoverability of the CoCl2N,N'-(1,2-phenylene)bis(2-aminobenzamide)/Al-SBA-15 catalyst and reusability with important preservation in its catalytic activity. 相似文献
995.
在线分析技术由于其具有实时、准确、高效的特点,近年来得到快速发展,已被广泛应用于环境、矿业、冶金、生物医药和食品等领域。重点介绍了国内X射线荧光光谱、激光诱导击穿光谱、瞬发γ中子活化、双能量γ射线透射、原子荧光光谱、近红外光谱和质谱法等在线分析技术近十年来的发展和应用情况,并对在线分析技术未来发展趋势进行了展望。 相似文献
996.
针对光纤级高纯四氯化锗(99.999999%)中痕量含氢杂质吸收峰红外透过率检测(FTIR)用试样的采集,以及痕量金属杂质的电感耦合等离子体质谱法(ICP-MS)测定用试样的制备方法进行了系统研究。设计开发了用于检测痕量含氢杂质吸收峰红外透过率的样品采集实验装置,实现了含氢杂质(如—OH、—CH、HCl等)吸收峰的红外透过率在线连续测试,试样采集过程全密闭进行,避免了采样过程的二次污染,采样过程流程简短,操作简便;实验优选了在制备ICP-MS法测定痕量金属杂质用的试样过程中消除四氯化锗基体干扰、防止砷等易挥发杂质损失以及防止样品处理过程污染试样的制样方法,实现了试样制备过程二次污染源的有效控制,制样过程试剂消耗量少,制备时间短,待测元素无损失。 相似文献
997.
Dr. Andrea Marraffa Dr. Piero Presenti Prof. Beatrice Macchi Dr. Francesca Marino-Merlo Prof. Mariella Mella Prof. Paolo Quadrelli 《ChemistryOpen》2020,9(5):528-537
Two new families of N,O-nucleoside analogues containing the anthracene moiety introduced through the nitrosocarbonyl ene reaction with allylic alcohols were prepared. The core structure is an isoxazolidine heterocycle that introduces either atom either a phenyl ring or dimethyl moiety at the C3 carbon. Different heterobases were inserted at the position 5 of the heterocyclic ring. One of the synthesized compounds demonstrated a good capacity to induce cell death and an appreciable nuclear fragmentation was evidenced in treated cells. 相似文献
998.
Kirill T. Kalinin Dr. Nikita G. Sedush Petr V. Dmitryakov Prof. Sergei N. Chvalun 《ChemistryOpen》2020,9(10):1027-1032
The kinetic of D,L-lactide polymerization in presence of biocompatible zirconium acetylacetonate initiator was studied by differential scanning calorimetry in isothermal mode at various temperatures and initiator concentrations. The enthalpy of D,L-lactide polymerization measured directly in DSC cell was found to be ΔH=−17.8±1.4 kJ mol−1. Kinetic curves of D,L-lactide polymerization and propagation rate constants were determined for polymerization with zirconium acetylacetonate at concentrations of 250–1000 ppm and temperature of 160–220 °C. Using model or reversible polymerization the following kinetic and thermodynamic parameters were calculated: activation energy Ea=44.51±5.35 kJ mol−1, preexponential constant lnA=15.47±1.38, entropy of polymerization ΔS=−25.14 J mol−1 K−1. The effect of reaction conditions on the molecular weight of poly(D,L-lactide) was shown. 相似文献
999.
Fang-Hua Zhao Zhong-Lin Li Shu-Fang Zhang Jian-Hui Han Mei Zhang Jun Han Yu-Wen Lin Jin-Mao You 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(2):148-158
Two new metal–organic frameworks (MOFs), namely, three‐dimensional poly[diaquabis{μ2‐1,4‐bis[(2‐methyl‐1H‐imidazol‐1‐yl)methyl]benzene}bis(μ2‐glutarato)dinickel(II)] monohydrate], {[Ni2(C5H6O4)2(C16H18N4)2(H2O)2]·H2O}n or {[Ni2(Glu)2(1,4‐mbix)2(H2O)2]·H2O}n, ( I ), and two‐dimensional poly[[{μ2‐1,4‐bis[(2‐methyl‐1H‐imidazol‐1‐yl)methyl]benzene}(μ2‐glutarato)zinc(II)] tetrahydrate], {[Zn(C5H6O4)(C16H18N4)]·4H2O}n or {[Zn(Glu)(1,4‐mbix)]·4H2O}n ( II ), have been synthesized hydrothermally using glutarate (Glu2?) mixed with 1,4‐bis[(2‐methyl‐1H‐imidazol‐1‐yl)methyl]benzene (1,4‐mbix), and characterized by single‐crystal X‐ray diffraction, IR and UV–Vis spectroscopy, powder X‐ray diffraction, and thermogravimetric and photoluminescence analyses. NiII MOF ( I ) shows a 4‐connected 3D framework with point symbol 66, but is not a typical dia network. ZnII MOF ( II ) displays a two‐dimensional 44‐ sql network with one‐dimensional water chains penetrating the grids along the c direction. The solid‐state photoluminescence analysis of ( II ) was performed at room temperature and the MOF exhibits highly selective sensing toward Fe3+ and Cr2O72? ions in aqueous solution. 相似文献
1000.
Zhong-Xuan Xu Guo-Guo Chen Li-Feng Li 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(2):125-132
The reactions of (R)‐ and (S)‐4‐(1‐carboxyethoxy)benzoic acid (H2CBA) with 1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene (1,3‐BMIB) ligands afforded a pair of homochiral coordination polymers (CPs), namely, poly[[[μ‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene][μ‐(S)‐4‐(1‐carboxylatoethoxy)benzoato]zinc(II)] monohydrate], {[Zn(C10H8O5)(C14H14N4)]·H2O}n or {[Zn{(S)‐CBA}(1,3‐BMIB)]·H2O}n ( 1‐L ), and poly[[[μ‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene][μ‐(R)‐4‐(1‐carboxylatoethoxy)benzoato]zinc(II)] monohydrate] ( 1‐D ). Three kinds of helical chains exist in compounds 1‐D and 1‐L , which are constructed from ZnII atoms, 1,3‐BMIB ligands and/or CBA2? ligands. When the as‐synthesized crystals of 1‐L and 1‐D were further heated in the mother liquor or air, poly[[μ‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene][μ‐(S)‐4‐(1‐carboxylatoethoxy)benzoato]zinc(II)], [Zn(C10H8O5)(C14H14N4)]n or [Zn{(S)‐CBA}(1,3‐BMIB)]n ( 2‐L ), and poly[[μ‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene][μ‐(R)‐4‐(1‐carboxylatoethoxy)benzoato]zinc(II)] ( 2‐D ) were obtained, respectively. The single‐crystal structure analysis revealed that 2‐L and 2‐D only contained one type of helical chain formed by ZnII atoms and 1,3‐BMIB and CBA2? ligands, which indicated that the helical chains were reconstructed though solid‐to‐solid transformation. This result not only means the realization of helical transformation, but also gives a feasible strategy to build homochiral CPs. 相似文献