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941.
采用高温固相法合成了绿色荧光粉Ca3Y2Si3O12:Tb3+.XRD检测结果显示,荧光粉主晶相为Ca3Y2Si3O12,属单斜晶系.荧光光谱分析表明:Ca3Y2Si3O12:Tb3+硅酸盐荧光粉可以被370 nm的近紫外光激发,发射绿光,主发射峰位于490 nm(5D4→7F6),544 nm(5D4→7F5),585 nm(5D4→7F4)和621 nm(5D4→7F3).用544 nm最强峰监测,得到主激发峰位于370 nm的激发光谱,此光谱覆盖了300~450 nm的波长范围.研究了煅烧条件、掺杂浓度及Ce3+共掺杂对荧光粉发光性能的影响:在1 400 ℃下经二次煅烧 6 h得到的样品的发光性能最佳,Tb3+离子的最佳掺杂浓度为20mol%,Ce3+离子共掺杂能够提高荧光粉的发光强度,其最佳掺杂量为4mol%,说明存在Ce3+→Tb3+的能量传递. 相似文献
942.
通过高效的反应精确合成功能分子已成为现代化学发展的趋势之一。基于呋喃/马来酰亚胺(MI)之间的Diels-Alder(D-A)反应作为一种高效的和高选择性的点击反应,克服了铜催化的叠氮/炔之间的1,3-偶极环化加成(CuAAC)反应中引起的金属污染等缺点,为生物医药载体、功能性材料的制备提供更可行的途径。同时,呋喃/MI之间的D-A反应具备原料易得、反应条件温和及易发生retro D-A(rD-A)反应等优点,在制备响应性材料领域备受关注。本文综述了近年基于呋喃/MI的可逆D-A反应在响应性聚合物合成、智能材料、生物分子及表面修饰等方面的应用,并展望了D-A反应的发展前景。 相似文献
943.
944.
HPLC-AFS联用测定海产品中砷的形态 总被引:2,自引:0,他引:2
建立了高效液相色谱-原子荧光分光光度法测定海产品中无机砷(As V,AsⅢ)、有机砷(DMA,MMA,AsB)含量的方法.样品经含10%(体积分数)HC1的提取液振荡提取、离心分离、二路形态分析预处理、高效液相色谱分离,用原子荧光光度计检测As(Ⅲ),DMA,MMA,As(v);四路条件(过氧化氢氧化和开启紫外灯)形态分析预处理装置处理,高效液相色谱分离,原子荧光光度计测定AsB.As(Ⅲ)线性范围为0~100.00 μg/L,r2=0.9997;DMA线性范围为0~100.00 μg/L,r2=0.9993;MMA线性范围为0~100.00 μg/L,r2=0.9990;As(Ⅴ)线性范围为0~100.00 μg/L,r2=0.999 1;AsB线性范围为0~200.00 μg/L,,r2=0.9994.3个样品加标回收率为As(Ⅲ)86.7%~89.4%,DMA 111.2%~117.0%,MMA 109.7%~111.6%,As(Ⅴ) 83.8%~90.7%,AsB 88.3%~90.4%.用该方法测定虾仁(干)5个价态测定结果的相对标准偏差为3.07%~9.93%(n=6).5个价态的检出限(S/N=2)为As(Ⅲ)0.29 μg/L,DMA 0.36 μg/L,MMA 0.27 μg/L,As(V) 0.56 μg/L,AsB l.46 μg/L.该方法适用于海产品中As(Ⅲ),DMA,MMA,As(V),AsB含量的测定. 相似文献
945.
946.
947.
A modified glassy carbon (GC) electrode was developed for the amperometric detection of biogenic amines, particularly histamine. The electrode was modified with the co‐enzyme pyrroloquinoline quinone (PQQ) by entrapment during electropolymerziation of pyrrole to form polypyrrole (PPy). This method formed a thin film on the electrode surface possessing very good stability with a shelf‐life exceeding one month without loss of signal. Optimal conditions for the PQQ/PPy electrode were determined and a linear response was found for histamine in phosphate buffer (pH 6) at +550 mV from 40 to 170 mg L?1 with a limit of detection (S/N≥3) of 38 mg L?1. The practical linear range offered by this method suggests ideal use for spoilage detection in fermented foods. 相似文献
948.
Hankun Zhou Si Chen Ning Gan Tianhua Li Yuting Cao Qianli Jiang 《Electroanalysis》2013,25(10):2384-2393
A novel sandwich‐type electrochemiluminescence (ECL) immunosensor was developed to enable the sensitive detection of HIV‐1 antibodies. This system incorporated mesoporous silica (mSiO2) complexed with quantum dots (QDs) and nano‐gold particles, which were assembled to enhance signal detection. Magnetic beads were used by immobilizing the secondary anti‐IgG antibody. This was first employed to capture HIV‐1 antibody (Ab) to form a Fe3O4/anti‐IgG/Ab complex. A high loading and signal‐enhanced nanocomposite (hereafter referred to as Au‐mSiO2‐CdTe) was used as a HIV‐1 antigen label. The Au‐mSiO2‐CdTe nanocomposite was conjugated with the Fe3O4/anti‐IgG/Ab complex to form an immunocomplex (hereafter referred to as Fe3O4/anti‐IgG/Ab/HIV‐1/CdTe‐mSiO2‐Au). This complex could be further separated by an external magnetic field to produce ECL signals. Due to the large specific surface area and pore volume of mSiO2, the loading of the CdTe QDs was markedly increased. Thus, the loaded QDs released a powerful chemiluminescent signal with a concordantly increased sensitivity of the immunosensor. The immunosensor was highly sensitive, and displayed a linear range of responses for HIV‐1 antibody across a dilution range of 1 : 1500 through 1 : 50 with the detection limit of 1 : 4500. The immunoassay can be a promising candidate in early diagnosis of HIV infection. 相似文献
949.
Yue-Wei Zhang Hai-Yu Yan Ping Fu Fei Jiang Yao Zhang Wen-Xue Wu Jin-Xiang Li 《Analytical and bioanalytical chemistry》2013,405(16):5549-5555
The recognition of targets such as biomacromolecules, viruses and cells by their aptamers is crucial in aptamer-based biosensor platforms and research into protein function. However, it is difficult to evaluate the binding constant of aptamers and their targets that are hard to purify and quantify, especially when the targets are undefined. Therefore, we aimed to develop a modified capillary electrophoresis based method to determine the dissociation constant of aptamers whose targets are hard to quantify. A protein target, human thrombin, and one of its aptamers were used to validate our modified method. We demonstrated that the result calculated by our method, only depending on the aptamer’s concentrations, was consistent with the classical method, which depended on the concentrations of both the aptamers and the targets. Furthermore, a series of DNA aptamers binding with avian influenza virus H9N2 were confirmed by a four-round selection of capillary electrophoresis–systematic evolution of ligands by exponential enrichment, and we identified the binding constant of these aptamers by directly using the whole virus as the target with the modified method. In conclusion, our modified method was validated to study the interaction between the aptamer and its target, and it may also advance the evaluation of other receptor–ligand interactions. 相似文献
950.
Tingting Wang Zhenghua Liu Jacques Crommen Zhengjin Jiang 《Journal of separation science》2013,36(9-10):1568-1574
In this study, the partial filling technique on both polycationic polymer hexadimethrine bromide (HDB) modified capillary and eCAP neutral capillary were systematically compared in order to enhance the enantioseparation ability of bromobalhimycin as CE additive. The separation conditions, such as pH, the plug length, and the concentration of bromobalhimycin, etc., were optimized in order to obtain satisfactory separations. As expected, for all tested 28 N‐benzoylated amino acids, up to five times higher enantioresolutions were obtained on the eCAP neutral capillary compared to that on the polycationic polymer hexadimethrine bromide modified capillary. Moreover, 26 of 28 tested racemic compounds were almost baseline‐ resolved without observing any interference from the front of the plug of bromobalhimycin. Although the limitation of longer running time on the neutral capillary, it allows the use of higher content of bromobalhimycin in the running buffer without any interference on the detection of analytes when enantioseparations are more difficult to obtain. 相似文献