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61.
This study reports the magnetic properties of newly reported nickel(II) complex of the antiprine Schiff base of 3-formylsalicylic
acid. Using the isotropic magnetic interaction model it is suggested that there is a strong antiferromagnetic interactions
between metal centers in dimeric units. It is also suggested that the system become demagnetized below a certain temperature.
An erratum to this article can be found at 相似文献
62.
Zobi F Spingler B Alberto R 《Chembiochem : a European journal of chemical biology》2005,6(8):1397-1405
We have synthesized and fully characterized four new complexes comprising the fac-[Re(CO)3]+ moiety and the ligands NH3, L-proline (Pro), or N,N-dimethylglycine (dmGly). The reaction of [Re(H2O)3(CO)3]+ with the two amino acids gives trinuclear complexes of general formula [Re(L)(CO)3]3 (where L = amino acid). We have studied the in vitro behavior of these compounds with guanine and DNA in order to understand whether the cytotoxicity exhibited by certain rhenium complexes based on the fac-[Re(CO)3]+ core is due to the formation of nucleobase complexes and inter- or intrastrand links between DNA bases. We have performed model studies with guanine and studied the structural effects induced by different rhenium(I) tricarbonyl complexes on PhiX174 plasmid DNA by electrophoretic methods. Our results show that rhenium complexes with two available coordination sites interact with plasmid DNA to form a stable adduct that is likely to involve two bases. 相似文献
63.
Yinfeng Liu Lai Chen Bei Su Aiming Huang Jiadong Hua Wenbin Sang Jiahua Min Zhongyan Meng 《应用聚合物科学杂志》2002,84(6):1263-1268
In this article nano‐sized CdS crystal embedded in a PEO matrix was successfully prepared by a complex transformation method that is universal for preparing nanosized compounds containing transition metals. The size of embedded CdS particles was in the nanoscale from 2 to 10 nm determined by X‐ray diffusion. The nanosized CdS displayed the expected blue shift of the onset absorbance in the UV spectrum. The amount of blue shift depends upon the dipping time of the PEO–cadmium complex film in a sodium sulfide solution as well as its concentration. The most effective means for adjusting the size of CdS nanocrystals is to change the ratio of the oxygen along with the PEO chain to the cadmium ion in the complex film. The alkali salt in the film would contribute to the conductivity of the composite film. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1263–1268, 2002; DOI 10.1002/app.10459 相似文献
64.
Hydrogen-bonded complexes of poly(acrylic acid) and poly(ethyl oxazoline) (PEOx) were prepared by photopolymerization of acrylic acid in which PEOx was dissolved. The glass transition temperatures (Tg) of the complexes are not only higher than those of the blends but also higher than the Tg value of either component polymer. The complexes dissolve in strong proton-accepting solvents like dimethyl formamide or dimethyl sulphoxide (DMSO), are swollen to various degrees in water and methanol, but are resistant to swelling by dioxane. When the density of hydrogen bond donor groups in the chain is reduced by 50% with the use of a copolymer of acrylic acid and methyl methacrylate, intermolecular association still takes place, although the affinity of complexation is reduced to some extent. When interpenetrating networks (semi-IPNs) are prepared by this method, about half of the PEOx can be extracted by DMSO after 4 days. The incomplete removal is probably a result of topographical constraints against diffusion. 相似文献
65.
Alaa?S.?Abd-El-AzizEmail author Nelson?M.?Pereira Waleed?Boraie Erin?K.?Todd Tarek?H.?Afifi Wes?R.?Budakowski Ken?J.?Friesen 《Journal of Inorganic and Organometallic Polymers and Materials》2005,15(4):497-509
The synthesis of the title complexes was achieved via the reaction of
-p-dichlorobenzene-
-cyclopentadienyliron cations with 4,4′-bis(4-hydroxyphenyl)valeric acid to produce the diiron complexes which were then reacted with a number of arylazo dyes to give cationic bis(cyclopentadienyliron)arene complexes containing the arylazo dyes. These iron-containing monomers were subsequently polymerized via nucleophilic aromatic substitution using 1,8-octanedithiol, 4,4′-thiobisbenzenethiol, or bisphenol A to produce the desired coloured cationic organoiron polymers. The weight – average molecular weights were estimated to range from 11,800 to 31,600. UV–vis studies conducted in dimethylformamide (DMF) showed that the metallated polymers exhibited
of 412–491 nm. Addition of HCl to the polymer solution caused a bathochromic shift into the range of 515–530 nm. Thermogravimetric analysis (TGA) revealed that the iron moieties were cleaved between 205 and 248 °C while the polyether/thioether backbone degraded between 380 and 613 °C. Differential scanning calorimetry (DSC) showed that the polymers exhibited glass transition temperatures (Tg) ranging from 106 to 184°C.This paper is dedicated to Professor Richard J. Puddephatt in recognition of his outstanding contribution to the field of metal-containing polymers. 相似文献
66.
Alaa S. Abd-El-Aziz T. Christopher Corkery Erin K. Todd Tarek H. Afifi Guozhang Ma 《Journal of Inorganic and Organometallic Polymers》2003,13(3):113-130
The synthesis of an aromatic ether complex of cyclopentadienyliron containing two terminal aldehyde groups was achieved via metal-mediated nucleophilic aromatic substitution reactions. This dialdehyde monomer was subsequently reacted with a variety of aliphatic and aromatic diamines to produce the corresponding soluble cationic organoiron polyether-imines. These cationic organometallic polymers were characterized using IR, 1H, and 13C NMR, viscosity and thermogravimetric analysis. Viscosity measurements showed that these polymers exhibited polyelectrolyte effects in DMSO solutions. Thermogravimetric analysis showed that decoordination of the iron moieties occurred at about 300°C for polymers with aliphatic spacers in their backbones, while the cyclopentadienyliron moieties were cleaved from the polymers with aromatic spacers in their backbones at about 200°C. Photolytic demetallation of the organoiron polymers resulted in the removal of the pendent cyclopentadienyliron moieties and allowed for the isolation of their organic analogs. While the organoiron polymers were soluble in polar organic solvents, the corresponding organic polymers exhibited very limited solubilities or were insoluble. The organic polymers had glass transition temperatures between 101 and 120°C 相似文献
67.
伴随超标准巨震、极端暴雨洪水、巨型滑坡等灾害频繁发生,极端载荷作用下梯级水电枢纽群的灾害风险分析与防控等问题成为当前水利工程领域的研究热点。为分析梯级水电枢纽群巨灾风险研究现状,绘制了国内外水库大坝溃坝事件的时间序列图,分析了梯级水电枢纽群的风险特征,总结评述了梯级水电枢纽群巨灾风险分析和巨灾防控研究进展,主要结论如下:1)梯级水电枢纽群巨灾风险是我国水利水电工程风险防控面临的主要问题;2)梯级水电枢纽群风险分析方面主要聚焦于梯级水库连溃概率的分析和计算,对于溃决可能产生的巨灾损失的量化研究不足,缺乏对巨灾因子及其相关影响作用下巨灾风险的评估;3)缺乏对梯级枢纽群灾害链的阻断技术研究和应急避险方案设计研究。为此提出了梯级水电枢纽群可能最大灾难(Probable Maximum Disaster, PMD)的科学内涵,考虑可能遭遇的多种致灾因子和承灾体特征,分析相互因果关系和极端荷载组合情况,初步建立了PMD评估的理论模型,为绘制梯级水电枢纽群在巨灾情景下的灾难空间外包线和估算PMD损失上限值提供科学依据,为梯级水电枢纽群巨灾风险分析和防控提供理论基础和技术支持。 相似文献
68.
蛋白质复合物识别对分析蛋白质网络的结构特征和模块功能具有重要意义。通常在蛋白质网络中挖掘稠密子图或模块来识别其中的蛋白质复合物,限制了其应用范围和识别的准确性。针对该问题,提出了一种基于加权网络和局部适应度的蛋白质复合物识别算法,该算法综合稠密子图的密度指标和模块性定义了新的局部适应度函数,并基于边聚集系数构建加权的蛋白质网络,根据权值选择边,在加权蛋白质网络中将种子边不断聚类扩展,从而获取具有最大综合适应度的子图作为蛋白质复合物。在酵母蛋白质等多个实际网络中试验表明,该算法能够有效提升蛋白质复合物识别的准确性。 相似文献
69.
合成了系列钆钐双核稀土有机配合物GdxSm1-x(TTA)3phen(x=0~0.9).红外光谱(IR)、X射线衍射(XRD)、热重(TG)结果推测了配合物可能的分子结构;紫外可见光谱(UV/vis)结果表明,该系列稀土有机配合物能有效的吸收紫外光,吸收峰主要来自于有机配体TTA和phen(270nm和351nm处);荧光光谱(FS)结果表明,Gd3+对于Sm3+具有荧光增效,当Gd3+的摩尔分数为0.6时,Gd0.6Sm0.4(TTA)3phen类配合物的特征荧光(562nm,596nm和643nm处)强度均达到最大. 相似文献
70.
SynthesisandCharacterizationofHeteropolyComplexesofIndiumwithMetal-centredUndecatungstateLigandsWuQingyin(吴庆银)(LiaoningUniver... 相似文献