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81.
Iron oxide catalyst with spinel structure used for dehydrogenation of ethylbenzene is one kind of important catalyst in petrochemical industry. In this work several series of industrial catalyst were prepared with different components and different manufacturing processes. Mössbauer Spectroscopy has been used to determine the optimal components and the better manufacturing process for spinel structure formation. The results may prove useful for producing the industrial dehydrogenation catalyst with better catalytic property. 相似文献
82.
小试金富集ICP-AES法同时测定试样中的铂、钯、金 总被引:16,自引:0,他引:16
文章报道了用小试金富集ICP AES法同时测定试样中的铂、钯和金 ,将 1 0~ 2 0g试样中的铂、钯、金富集在毫克量的银合粒中 ,制成溶液后用ICP AES法同时测定铂、钯和金。该方法的检出限 (μg·mL-1 )Pt,Pd ,Au分别为 0 0 1 ,0 0 0 5 ,0 0 1 ,相对标准偏差 (RSD ,n =1 0 )分别为 0 1 % ,0 1 2 % ,0 0 9% ,标准回收率均在 97%以上。生产实践表明 ,本方法是一种快速、简便、准确的分析方法 ,已被我们应用于测定样品中的铂 ,钯和金 相似文献
83.
催化动力学荧光法测定中草药对羟基自由基的清除率 总被引:11,自引:1,他引:11
苯甲酸具有很弱的荧光,在Co2+的催化下,过氧化氢能氧化苯甲酸发出强的荧光。中草药提取物可以清除溶液中的·OH, 使产物的生成量减少, 从而使溶液的荧光增加程度降低。据此原理建立了一种测定中草药对羟基自由基清除率的催化动力学荧光新体系。当中草药的浓度为4.0 mg(干重)·mL-1时,测得紫花地丁、苍术和赤芍对羟基自由基的清除率分别为60.8%,40.1%和94.3%。该方法与分光光度法测定结果相比无显著性差异。 相似文献
84.
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86.
Some studies on quantum dots (QD) as donors that enhance the fluorescence of a dye as an acceptor through fluorescence resonance energy transfer (FRET) have been reported. However, in the present work we discovered that CdS quantum dots sharply quenched the fluorescence of acridine orange (AO). Also, DNA enhanced the fluorescent signals of AO quenched by CdS. The extents of enhancement were in good proportion to the DNA concentrations. Based on this, a sensitive method was employed to determine DNA with both good selectivity and sensitivity. The calibration curve was linear over 60-4,000 ng mL(-1) and the determination limit (3sigma) was 4.39 ng mL(-1). 相似文献
87.
P. Dietrich F. Michalik R. Schmidt C. Gahl G. Mao M. Breusing M. B. Raschke B. Priewisch T. Elsässer R. Mendelsohn M. Weinelt K. Rück-Braun 《Applied Physics A: Materials Science & Processing》2008,93(2):285-292
A mild and efficient procedure has been developed to obtain covalently attached self-assembled monolayers (SAMs) on Si(111)
with photochromic azobenzene head-groups. Starting from neat or diluted carboxylic acid functionalized monolayers on-chip
coupling reactions were applied to attach hydroxyl-functionalized azobenzene units to the SAMs by ester bond formation. The
modified surfaces were characterized by high-resolution X-ray photoelectron spectroscopy (XPS), transmission Fourier transform
infrared spectroscopy (FT-IR), and contact angle measurements. Reversible cis
↔
trans isomerizations of photoswitchable SAMs were monitored by wettability measurements.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users.
Dedicated with respect and compliments to Professor Helmut Schwarz on the occasion of his 65th birthday. 相似文献
88.
89.
报导了Yb :FAP和Yb :C3S2 _FAP晶体在不同温度下的吸收光谱和荧光光谱实验结果 ,研究发现由于电子_声子近共振耦合作用 ,Yb :FAP和Yb :C3S2 _FAP晶体均存在有明显的振动谱 ,Yb :FAP晶体的零声子线在低温下还劈裂为相差 10cm- 1 的两条线 .采用激光选择激发技术研究了Yb3 离子在FAP和C3S2 _FAP晶体中的格位特征 ,结果表明Yb3 离子在这两种基质中都只占据Ca(Ⅱ )格位 ,但由于CaF2 的挥发 ,导致了Ca(Ⅱ )格位的局部畸变 . 相似文献
90.
Based on the state equation of an ideal quantum gas, the regenerative loss of a
Stirling engine cycle working with an ideal quantum gas is calculated. Thermal
efficiency of the cycle is derived. Furthermore, under the condition of quantum
degeneracy, several special thermal efficiencies are discussed. Ratios of thermal
efficiencies versus the temperature ratio and volume ratio of the cycle are made. It
is found that the thermal efficiency of the cycle not only depends on high and low
temperatures but also on maximum and minimum volumes. In a classical gas state
the thermal efficiency of the cycle is equal to that of the Carnot cycle. In an ideal
quantum gas state the thermal efficiency of the cycle is smaller than that of the
Carnot cycle. This will be significant for deeper understanding of the gas Stirling
engine cycle. 相似文献