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81.
Synthesis of CuI Trifluoromethylselenates for Trifluoromethylselenolation of Aryl and Alkyl Halides 下载免费PDF全文
Chaohuang Chen Li Ouyang Quanfu Lin Yanpin Liu Chuanqi Hou Prof. Dr. Yaofeng Yuan Prof. Dr. Zhiqiang Weng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(3):657-661
The development of new strategies for synthesis of trifluoromethylthiolate compounds is of considerable importance in pharmaceuticals, agrochemicals, and advanced materials. Accordingly, currently much attention is being devoted to the development of effective methods and reagents for their synthesis. In contrast, considerably less effort has been afforded to the development of preparing C?SeCF3 bonds. Herein we report a concise route to synthesize a family of copper(I) trifluoromethylselenolate reagents by the reaction of CuI with the Ruppert’s reagent (Me3SiCF3), KF, and elemental selenium in the presence of dinitrogen ligands in CH3CN at room temperature. The reagent [Cu(bpy)(SeCF3)]2 was proven to be air‐stable and highly efficient for nucleophilic trifluoromethylthselenolation of a broad range of (hetero)aryl halides and alkyl halides. This method represents a powerful protocol for the construction trifluoromethylselenolate compounds. 相似文献
82.
We report the chemical design and development of 3-aryl-substituted 7-alkoxy-4-methylcoumarins with enhanced fluorogenic properties. The 3-aryl substituents are installed via an optimized Suzuki–Miyaura cross-coupling (SMC) reaction between a 7-alkoxy-3-bromo-4-methylcoumarin and aryl boronic MIDA esters using Pd(OAc)2/XPhos in a catalytic system with K2CO3 in aqueous THF. Under these conditions, an exocyclic ester functionality is found to be unaffected. Subsequent saponification revealed a carboxylic acid functionality that is suitable for conjugation reactions. Evaluation of their fluorescence properties indicated that the installed 3-heteroaryl substituent, particularly benzofuran-2-yl, resulted in a significant red shift of both the excitation and emission wavelengths. 相似文献
83.
Bixia Yao Fengping Zhan Guangyan Yu Zhifen Chen Wenjing Fan Xiongping Zeng Qingle Zeng Wen Weng 《Journal of chromatography. A》2009,1216(28):5429-5435
In this work, the enantioseparations of 1,1′-bi-2-naphthol (BINOL) and its three derivatives were performed on an immobilized polysaccharide-based chiral stationary phase, Chiralpak IA, under normal-phase mode. The effects of the content of polar modifier in the mobile phase and the column temperature on the retention and enantioseparation were investigated in detail. Temperature-induced inversion of elution order for BINOL was observed directly when n-hexane/2-propanol (92/8, v/v) was used as mobile phase. The isoenantioselective temperature (Tiso) was calculated to be 31.4 °C. When n-hexane/2-propanol/THF (93/2/5, v/v/v) was used as mobile phase, the Tiso value decreased to −8.2 °C. Entropically driven enantioseparation which had practical application was obtained successfully (separation factor being 1.189 and 1.332 at 25 °C and 50 °C, respectively). The corresponding thermodynamic parameters for other three binaphthyl compounds were compared with that for BINOL. Some inferences about chiral recognition mechanism were stressed. 相似文献
84.
Qian Qiao Guo‐Qiang Wu Tian‐Di Tang Seik Weng Ng 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(4):m146-m148
In the title PbII coordination polymer, [Pb(C16H10O4)(C14H8N4)(C3H7NO)]n, each PbII atom is eight‐coordinated by two chelating N atoms from one pyrazino[2,3‐f][1,10]phenanthroline (L) ligand, one dimethylformamide (DMF) O atom and five carboxylate O atoms from three different 4,4′‐ethylenedibenzoate (eedb) ligands. The eedb dianions bridge neighbouring PbII centres through four typical Pb—O bonds and one longer Pb—O interaction to form a two‐dimensional structure. The C atoms from the L and eedb ligands form C—H...O hydrogen bonds with the O atoms of eedb and DMF ligands, which further stabilize the structure. The title compound is the first PbII coordination polymer incorporating the L ligand. 相似文献
85.
为了寻找生物活性良好的噻唑基丙烯腈类化合物, 利用2-[4-(2,6-二氟苯基)噻唑-2-基]乙腈(3)分别与取代氯甲酸酯4和取代苯基异氰酸酯6在碱存在下反应, 合成了8个2-[4-(2,6-二氟苯基)噻唑-2-基]-3-羟基-3-烃氧基丙烯腈化合物5和7个2-[4-(2,6-二氟苯基)噻唑-2-基]-3-羟基-3-取代苯胺基丙烯腈化合物7, 均为首次报道的丙烯腈类化合物. 化合物结构经1H NMR, IR, MS和元素分析表征. 初步生物活性测定结果表明, 在试验浓度下, 目标化合物均具有一定的杀虫和抑菌活性, 其中化合物5f和5h在100 mg/L浓度下对炭疽病菌的抑制率达95%; 化合物5g和7d在250 mg/L浓度下对棉红蜘蛛的致死率达85%. 相似文献
86.
Weizhong Lv Zhongkuan Luo Wenjian Weng Hui Yang 《Journal of Sol-Gel Science and Technology》2009,51(1):58-62
A series of organic–inorganic hybrid coatings consisting of organic waterborne polyurethane (WPU) and inorganic nanosized
bismuth-doped tin dioxide were successfully synthesized by the in situ polymerization approach. Bi0.1Sn0.9O2 nano-powders were prepared via a new route of sol–gel combustion hybrid method using acetylene black as the fuel. The formed
nano-powders were characterized by transmission electron microscopy and X-ray diffraction (XRD). Bi0.1Sn0.9O2–WPU was then fabricated with isophorone diisocyanate, 2,2-bis(hydroxymethyl) propionic acid and nano-Bi0.1Sn0.9O2-poly(ε-caprolactone) (PCL) as the starting materials. Organic–inorganic hybrid coatings are always achieved with adjustable
contents of Bi0.1Sn0.9O2. The hybrid coatings with Bi0.1Sn0.9O2 loading on the glass substrate exhibited good heat insulation efficiency. The tensile strength and breaking extensibility
of nanocomposite film containing 1.0% of the nano-Bi0.1Sn0.9O2 were measured as 9.35 MPa and 248%, respectively. The transmittance of visible light was above 80%. The heat insulation of
glass coated with nano-Bi0.1Sn0.9O2–WPU hybrid was over 60 °C in contrast to the commercial blank glass. 相似文献
87.
Replication of microstructures from a mold onto a curved surface is difficult. The conformal contact between the mold and the substrate has to be ensured. The present study proposes an innovative mechanism, which employs an electromagnetic disk to provide magnetic force and a PDMS flexible mold with a layer compounded magnetic powder. This mechanism provides not only the gradual contact from center to edge to avoid air entrapment but also conformal contact between the mold and the substrate during the imprinting operation. A system based on this electromagnetic soft imprinting technology has been implemented, and imprinting to replicate microstructures from the mold onto a curved surface has been carried out. The results reveal that the PDMS magnetic mold and the electromagnetic disk‐controlled magnetic force can successfully perform the imprinting and accurately replicate the microstructures onto the large‐area, curved surface glass. The PDMS flexible magnetic mold incorporated with the magnetic disk can be employed to achieve the conformal contact between the mold and the substrate. In addition, due to the low surface free energy of the PDMS, the de‐molding without sticking can be easily accomplished. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
88.
Guo-Bin Jung Cheng-Hsin Tu Pei-Hung Chi Ay Su Fang-Bor Weng Yur-Tsai Lin Yu-Chun Chiang Chi-Yuan Lee Wei-Mon Yan 《Journal of Solid State Electrochemistry》2009,13(9):1455-1465
An experimental and simulation research had been performed to investigate the performance as well as the flow distribution
in the cathode flow field in the case of direct methanol fuel cells (DMFCs). The gas was well distributed in serpentine flow
field, whereas stagnation of the gas was observed in parallel flow field. These would contribute to the cell performance greatly
due to mass transfer effect when the cells start operating. In addition, the durability test of DMFC was drastically affected
in parallel flow field due to poor ability to drain flooded water produced electrochemically at cathode and crossover from
anode. In addition, pressure drops of different flow fields were also investigated to evaluate their contribution and feasibility
as an economic application for DMFC. DMFC with serpentine flow field featuring higher pressure difference resulted in a larger
parasitic energy demand. However, the optimal flow field designs are needed to balance the performance and pressure loss to
achieve a uniform fluid distribution and simultaneously minimize energy demand for mass transport. Consequently, flow field
with grid pattern appears to be the optimal design for the DMFC cathode. 相似文献
89.
高硅煤中Si-Al-Fe-Ca四元体系碳热反应研究 《燃料化学学报》2017,45(11):1296-1302
研究了不同温度条件下高硅煤中矿物组成比例下的Si-Al-Fe-Ca多元体系的碳热反应以及其影响因素。通过XRD和FESEM-EDS技术对各还原产物进行分析。结果表明,Fe_2O_3对含硅矿物的碳热反应起促进作用,Fe可以有效提高Si反应活性。CaO在较低温度时与灰中的Al_2O_3和SiO_2反应形成致密的Ca-Al-Si相共熔体CaAl_2Si_2O_8,阻碍含硅矿物碳热反应的进行。随着温度的升高,继续反应生成SiC、CaAl_4O_7和CaSiO_3。热力学模拟计算与实验结果基本吻合。 相似文献
90.
In order to shorten the evaluation cycle of cobalt catalyst before the optimized catalyst is fixed on, a mathematical method is proposed to calculate weight percentage of C5+ hydrocarbons. Based on the carbide polymerization mechanism and the main hydrocarbons being linear alkanes and α-olefins, the correlation between hydrocarbon distribution and the molecular mass ratio of water to hydrocarbons is discussed. The result shows the ratio was within the range of 1.125-1.286 and the lower the ratio, the more gaseous hydrocarbons were obtained. Moreover, a linear equation between the weight percentage of C5+ hydrocarbons and the weight ratio of C5+ hydrocarbons to the total water is established. These results are validated by corresponding experiments. The weight percentage of C5+ hydrocarbons could be immediately calculated by this linear equation without detailed gas chromatography (GC) analysis of them. 相似文献