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1.
Boris Šobot 《Annals of Pure and Applied Logic》2021,172(1):102857
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《Mendeleev Communications》2022,32(5):597-600
Calorimetric monitoring of the autoclave reaction N2O4 + C2H4 at –85 to +10 °C under argon pressure 10–30 bar revealed that the exothermic chemical reaction started at temperatures above –52 °C at 10 bar, whereas an intensive exothermic reaction started at –85 °C and pressure of 30 bar. IR study showed that oligo/polynitroethylene was formed at 30 bar, while carbonyl and hydroxy compound as well as nitrate R–ONO2 formation occurred upon processing at 10 bar. 相似文献
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将一种人工合成的无机聚合物——蒙脱石皂石黏土(smectite,Sm)应用于基质辅助激光解吸电离飞行时间质谱分析(matrix-assisted laser desorption/ionization time of flight mass spectrometry, MALDI-TOF-MS),以检测糖类化合物。 将传统的有机基质2,4,6-三羟基苯乙酮(trihydroxyacetophenone, THAP)与阳离子交换后的皂石黏土混合制备成新型复合基质,应用于糖类化合物的检测。通过比较不同的制样方法,测定不同分子直径的糖类化合物,发现由于受复合基质晶面间距的限制,只有小分子糖类化合物能进入晶面间隙充分接触有机基质并被离子化,从而实现对小分子糖类化合物的选择性检测。 相似文献
6.
Hua‐Ming Xiao Xian Wang Xing Yang Feng Zheng Yu‐Qi Feng 《Journal of mass spectrometry : JMS》2019,54(3):239-249
Hydralazine has been widely employed in the development of drugs, derivatization reagents, and ligands. In the present work, we reported a new type of dehydrogenated ion [M ? H]+ that was produced from the hydralazine derivative of hexanal in electrospray ionization mass spectrometry (ESI‐MS). The formation of [M ? H]+ ions in the ESI‐MS was found to be independent on the mobile phase composition of the liquid chromatography and ESI source parameters. A series of hydralazine derivatives of aldehyde were investigated to confirm this phenomenon. The results showed that hydralazine derivatives of aldehydes that contained an sp3 hybridization carbon with a hydrogen at the α‐position of aldehydes could form the unexpected [M ? H]+ ions, whereas hydralazine derivative of acetone could only generate [M + H]+ ion in the ESI‐MS. We proposed the possible formation mechanism of [M ? H]+ ion for the hydralazine derivatives of aldehydes: the [M ? H]+ ion was possibly formed by the loss a hydrogen molecule (H2) from the protonated ion [M + H]+. The results obtained from density functional theory (DFT) calculations supported this proposed formation mechanism of [M ? H]+ ion. 相似文献
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The effect of the properties of sulphur and selenium atoms, the composition and location of substituents (―CH3, ―OCH3, ―C2H5, and ―C3H6―((N+Br?)C5H5)), and the charge state on the collision induced dissociation (CID) behaviour of ions generated by electrospray ionization (ESI) of thiocarbocyanine and selenocarbocyanine dyes have been investigated. The results show that, for of all the examined singly charged ions, the main dissociation channel was related to the formation of distonic ions, generated as a result of cleavages within the dimethine bridge. In the case of doubly charged ions (with propyl‐pyridinium substituents), competition between fragmentation processes related to charges located at different nitrogen atoms has been observed. The S/Se replacement also has an impact on the CID behaviour of the examined carbocyanine dyes. On the basis of the performed CID MS/MS experiments, general rules for the CID of thiocarbocyanine and selenocarbocyanine dyes have been proposed. 相似文献
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Electrospray ionization mass spectrometry (ESI‐MS) is a useful technique for solving organometallic and coordination chemistry characterization problems that are difficult to address using traditional methods. However, assigning the ESI mass spectra of such compounds can be challenging, and the considerations involved in doing so are quite different from assigning the mass spectra of purely organic samples. This is a tutorial article for organometallic/coordination chemists using ESI‐MS to analyze pure compounds or reaction mixtures. The fundamentals of assigning ESI mass spectra are discussed within the context of organometallic and coordination systems. The types of ions commonly observed by ESI‐MS are categorized and described. Finally, a step‐by‐step guide for the assignment of organometallic and coordination chemistry ESI mass spectra is provided along with two case studies. 相似文献
9.
大气压空气电火花激波等离子体射流的电子密度在亚微秒时间尺度上瞬变,其电子密度的测定很难.基于微波瑞利散射原理,本文测量了空气电火花冲击波流注放电等离子体射流的时变电子密度.实验结果表明:测量系统的标定参数A为1.04 × 105 V·Ω·m–2;空气流注放电等离子体射流的电子密度与等离子体射流的半径和长度有关,结合高速放电影像展示的等离子体射流的等效半径和等效长度,测定的电子密度在1020 m–3的量级,且随时间先快速增长至峰值再成指数衰减.此外,本文还探讨了等离子体射流的不同等效尺度对测定结果的影响;分析结果表明,采用时变等效半径和时变等效长度的计算结果最有效,且第1个快速波峰是由光电离的电离波导致的. 相似文献
10.
利用密度泛函理论(DFT)研究3d过渡金属掺杂硅团簇的几何结构和稳定性,计算了绝热电子亲和能和垂直电离能,内嵌双金属间距,自旋磁矩等.结果表明内嵌的Sc、Ti、V、Mn金属二聚体和十二面体硅笼构成了稳定的富勒烯结构,随着d电子数目的增加其内嵌的富勒烯构型有部分畸变,总体而言Si_(20)团簇掺杂双金属后稳定性得到了提高. 相似文献