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591.
湖泊沉积物中邻苯二甲酸酯类的GC/MS分析 总被引:7,自引:1,他引:7
东湖沉积物阴干后用二氯甲烷溶剂萃取,用DB-5弹性石英毛细管柱GC/MS分离鉴定,并结合m/z149质量色谱图,确证东湖沉积物中含有9种邻苯二甲酸酯类化合物,它们是邻苯二甲酸二乙酯、二异丁酯、二正丁酯、二己酯、己基辛基酯、二-(2-乙基己基)酯、二辛酯、己基癸基酯和辛基癸基酯,其特征离子及峰度见表1。 相似文献
592.
593.
By utilizing nanomaterials including one-dimensional materials (1DMs) and two-dimensional materials (2DMs), the recent development for the determination of multiple biomolecules has been focused. 相似文献
594.
Single-crystal CdSe nanosaws 总被引:5,自引:0,他引:5
We report the first successful synthesis and characterization of single-crystal wurtzite CdSe nanoribbons through a simple thermal evaporation process. Asymmetric growth of the nanoribbons occurs, yielding a sawlike shape with sharp teeth on one side. This asymmetric growth is suggested to be induced by the polarization of the c-plane in the wurtzite crystal structure. 相似文献
595.
Busacca CA Lorenz JC Grinberg N Haddad N Hrapchak M Latli B Lee H Sabila P Saha A Sarvestani M Shen S Varsolona R Wei X Senanayake CH 《Organic letters》2005,7(19):4277-4280
[reaction: see text] Diisobutylaluminum hydride (DIBAL-H) and triisobutylaluminum have been found to be outstanding reductants for secondary phosphine oxides (SPOs). All classes of SPOs can be readily reduced, including diaryl, arylalkyl, and dialkyl members. Many SPOs can now be reduced at cryogenic temperatures, and conditions for preservation of reducible functional groups have been found. Even the most electron-rich and sterically hindered phosphine oxides can be reduced in a few hours at 50-70 degrees C. This new reduction has distinct advantages over existing technologies. 相似文献
596.
Gao L Shi L An Y Zhang W Shen X Guo S He B 《Langmuir : the ACS journal of surfaces and colloids》2004,20(12):4787-4790
In this letter we describe a simple physical method for the ordered aggregation of scattered single spherical polystyrene-b-poly(acrylic acid) (PS-b-PAA) micelles. First, narrow dispersed spindlelike aggregates, about 60 nm in diameter and 1.5 microm in length, are obtained from the aggregation of single spherical PS-b-PAA micelles at 0 degrees C on a glass slide. Then, the yielding spindlelike units can further aggregate into long-ranged, close-packed, flowerlike arrays after a given amount of freeze-thaw cycles. The formation of the interesting arrays is ascribed to the templated aggregation of micelles on the water polycrystal at the freezing point. 相似文献
597.
高分子表面改性剂的分子设计 总被引:15,自引:2,他引:15
简述高分子表面改性剂对聚合物进行表面改性的微观模型,讨论了高分子表面改性剂的分子结构、分子量以及加工工艺条件对表面改性效果的影响,提出了高分子表面改剂的分子设计原则。 相似文献
598.
Hua Zhang Meng Xu Xudong Shi Yuan Liu Zihui Li Justin C. Jagodinsky Min Ma Nathan V. Welham Zachary S. Morris Lingjun Li 《Chemical science》2021,12(23):8115
Elucidating the isomeric structure of free fatty acids (FAs) in biological samples is essential to comprehend their biological functions in various physiological and pathological processes. Herein, we report a novel approach of using peracetic acid (PAA) induced epoxidation coupled with mass spectrometry (MS) for localization of the C C bond in unsaturated FAs, which enables both quantification and spatial visualization of FA isomers from biological samples. Abundant diagnostic fragment ions indicative of the C C positions were produced upon fragmentation of the FA epoxides derived from either in-solution or on-tissue PAA epoxidation of free FAs. The performance of the proposed approach was evaluated by analysis of FAs in human cell lines as well as mapping the FA isomers from cancer tissue samples with MALDI-TOF/TOF-MS. Merits of the newly developed method include high sensitivity, simplicity, high reaction efficiency, and capability of spatial characterization of FA isomers in tissue samples.A structural lipidomics approach employs peracetic acid-induced epoxidation coupled with mass spectrometry for pinpointing C C bonds in unsaturated fatty acids, enabling both quantification and imaging of FA isomers from biological samples. 相似文献
599.
It is shown that 4,8‐diphenylazulene ( 1 ) can be easily prepared from azulene by two consecutive phenylation reactions with PhLi, followed by dehydrogenation with chloranil. Similarly, a Me group can subsequently be introduced with MeLi at C(6) of 1 (Scheme 2). This methylation led not only to the expected main product, azulene 2 , but also to small amounts of product 3 , the structure of which has been determined by X‐ray crystal‐structure analysis (cf. Fig. 1). As expected, the latter product reacts with chloranil at 40° in Et2O to give 2 in quantitative yields. Vilsmeier formylation of 1 and 2 led to the formation of the corresponding azulene‐1‐carbaldehydes 4 and 5 . Reduction of 4 and 5 with NaBH4/BF3 ? OEt2 in diglyme/Et2O 1 : 1 and BF3 ? OEt2, gave the 1‐methylazulenes 6 and 7 , respectively. In the same way was azulene 9 available from 6 via Vilsmeier formylation, followed by reduction of azulene‐1‐carbaldehyde 8 (Scheme 3). The thermal reactions of azulenes 1, 6 , and 7 with excess dimethyl acetylenedicarboxylate (ADM) in MeCN at 100° during 72 h afforded the corresponding heptalene‐4,5‐dicarboxylates 11, 12 , and 13 , respectively (Scheme 4). On the other hand, the highly substituted azulene 9 gave hardly any heptalene‐4,5‐dicarboxylate. 相似文献
600.