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排序方式: 共有210条查询结果,搜索用时 15 毫秒
51.
KTP和7.5mol%Nb:KTP晶体在Nd:YAG激光中的倍频和和频 总被引:1,自引:1,他引:0
本文在获得精确的7.5mol%Nb:KTP晶体的Sellmeier主折射率色散方程的基础上,计算7.5mol%Nb:KTP晶体对1.0642μm和1.3188μmNd:YAG激光的倍频和和频的型相位匹配曲线.通过研究KTP和7.5mol%Nb:KTP晶体的主折射率,双折射率和相位匹配,可以看出Nb掺入KTP晶体后产生的折射率和双折射率的色散和各向异型的变化是引起KTP晶体相位变化的根本原因. 相似文献
52.
Wenzhi Hu Paul R. Haddad Kyioshi Hasebe Helmy A. Cook James S. Fritz 《Analytical and bioanalytical chemistry》2000,367(7):641-644
The inability to separate fluoride, phosphate and sulfate by electrostatic ion chromatography (EIC) was overcome by using an ODS silica column coated with mixed zwitterionic-cationic surfactants as the stationary phase. The best results were obtained using the zwitterionic surfactant, 3-(N,N-dimethylmyristylammonium)-propanesulfonate (C19H41NO3S), and the cationic surfactant, myristyltrimethylammonium, CH3(CH2)13N+(CH3)3, in a 10:1 molar ratio in the column coating solution. With a dilute solution of sodium tetraborate as the eluent the model analyte anions were completely separated in the following elution order: F–, HPO4 2–, SO4 2–, Cl–, NO2 –, Br–, NO3 –. The very early elution of phosphate and sulfate is most unusual and is unique to this system. Detection limits better than 1.1 × 10–4 mM and linear calibration plots up to 7.0 mM were obtained with a suppressed conductivity system. 相似文献
53.
直读光谱法快速测定无锡薄钢板铬层镀铬量 总被引:2,自引:1,他引:1
本文提出了直读光谱仪测定无锡薄钢板铬层铬量的新方法。通过选用基体元素的内标元素,引入Id/I0×100%来判断原板痕量铬对实验结果的影响程度,选择合适条件,解决了薄板易击穿,确保不同铬量无锡薄板的内标元素光强直稳定性等技术关键,采用比色法制作一套不同镀铬量的标准无镀锡薄板,绘制校准曲线,方法精度RSD小于3.0%,准确度为150±5mg/m^2与经典方法比较该法操作简单,分析速度快。 相似文献
54.
Wenxuan Zhang Zhanpeng Liu Chengjian Xu Wenzhi He Guangming Li Juwen Huang Haochen Zhu 《Research on Chemical Intermediates》2018,44(9):5075-5089
The wide use of lithium ion batteries (LIBs) has created much waste, which has become a global issue. It is vital to recycle waste LIBs considering their environmental risks and resource characteristics. Anode graphite from spent LIBs still possess a complete layer structure and contain some oxygen-containing groups between layers, which can be reused to prepare high value-added products. Given the intrinsic defect structure of anode graphite, copper foils in LIB anode electrodes, and excellent properties of graphene, graphene oxide–copper composite material was prepared in this work. Anode graphite was firstly purified to remove organic impurities by calcination and remove lithium. Purified graphite was used to prepare graphene oxide–copper composite material after oxidation to graphite oxide, ultrasonic exfoliation to graphene oxide (GO), and Cu2+ adsorption. Compared with natural graphite, preparing graphite oxide using anode graphite consumed 40% less concentrated H2SO4 and 28.6% less KMnO4. Cu2+ was well adsorbed by 1.0 mg L?1 stable GO suspension at pH 5.3 for 120 min. Graphene oxide–copper composite material could be successfully obtained after 6 h absorption, 3 h bonding between GO and Cu2+ with 3/100 of GO/CuSO4 mass ratio. Compared to CuO, graphene oxide–copper composite material had better catalytic photodegradation performance on methylene blue, and the electric field further improved the photodegradation efficiency of the composite material. 相似文献
55.
Ito K Takayama Y Ikedo M Mori M Taoda H Xu Q Hu W Sunahara H Hayashi T Sato S Hirokawa T Tanaka K 《Journal of chromatography. A》2004,1039(1-2):141-145
The determination of seven aliphatic carboxylic acids, formic, acetic, propionic, isobutyric, n-butyric, isovaleric and n-valeric acids in anaerobic digestion process waters was examined using ion-exclusion chromatography with conductimetric detection. The analysis of these biologically important carboxylic acids is necessary as a measure for evaluating and controlling the process. The ion-exclusion chromatography system employed consisted of polymethacrylate-based weakly acidic cation-exchange resin columns (TSKgel OApak-A or TSKgel Super IC-A/C). weakly acidic eluent (benzoic acid), and conductimetric detection. Particle size and cation-exchange capacity were 5 microm and 0.1 meq./ml for TSKgel OApak-A and 3 microm and 0.2 meq./ml for TSKgel Super IC-A/C, respectively. A dilute eluent (1.0-2.0 mM) of benzoic acid was effective for the high resolution and highly conductimetric detection of the carboxylic acids. The good separation of isobutyric and n-butyric acids was performed using the TSKgel Super IC-A/C column (150 mm x 6.0 mm i.d. x 2). The simple and good chromatograms were obtained by the optimized ion-exclusion chromatography conditions for real samples from mesophilic anaerobic digestors, thus the aliphatic carboxylic acids were successfully determined without any interferences. 相似文献
56.
57.
An electrostatic ion chromatographic (IC) method for rapid and direct determination of iodide in seawater is reported. Separation was achieved using a reversed-phase ODS packed column (250x4.6 mm I.D.) modified by coating with Zwittergent-3-14 micelles, with an eluent comprising an aqueous solution containing 0.2 mM NaClO4 and 0.3 mM Zwittergent-3-14 and using UV detection at 210 nm. Samples prepared by dissolving NaIO3, NaNO2, NaBr, NaBrO3, NaNO3, NaI, and NaSCN in artificial or real seawaters were analyzed using this IC system. Nitrite, iodate, bromide, bromate, and nitrate showed very little or no retention, while iodide and thiocyanate were well separated, being eluted within 6 and 16 min, respectively. The detection limit for iodide obtained by injecting 400 microL of sample was 0.011 microM (S/N = 3), and the precision values obtained by analyzing samples containing 0.1 or 0.3 microM iodide in real seawater samples were 2.3% RSD and 1.2% RSD, respectively. Direct determination of iodide in real seawater samples was possible using this proposed IC system. 相似文献
58.
Wenzhi Sun 《Archive for Mathematical Logic》1993,32(6):429-442
Summary This paper will define a new cardinal called aStationary Cardinal. We will show that every weakly
1
1
-indescribable cardinal is a stationary cardinal, every stationary cardinal is a greatly Mahlo cardinal and every stationary set of a stationary cardinal reflects. On the other hand, the existence of such a cardinal is independent of that of a
1
1
-indescribable cardinal and the existence of a cardinal such that every stationary set reflects is also independent of that of a stationary cardinal. As applications, we will show thatV=L implies
1
holds if is
1
1
-indescribable and so forth. 相似文献
59.