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161.
低共熔混合锂盐相图的绘制及应用 总被引:3,自引:0,他引:3
采用热分析法对不同组成的混合锂盐二元体系进行研究, 绘制了混合锂盐体系的步冷曲线和T-x相图, 结果表明体系均为具有最低共熔点的二元体系. LiOH-LiNO3、LiOH-LiCl、LiOH-Li2CO3及LiNO3-LiCl体系的最低共熔点分别为175.7、294.5、418.2及221.6 ℃. 利用低共熔混合物LiNO3-LiOH为锂盐与不同前驱体反应, 制备出了层状结构良好的锂离子电池正极材料LiNiO2、LiNi0.8Co0.2O2及LiNi1/3Co1/3Mn1/3O2. X射线衍射分析表明, 合成的材料具有规整的层状NaFeO2结构, 且XRD衍射峰强度之比I(003)/I(104)>2.0, 电性能测试表明, 在2.7-4.3 V(vs Li/Li+)的电压范围内进行0.1C倍率充放电, LiNiO2、LiNi0.8Co0.2O2、LiNi1/3Co1/3Mn1/3O2首次充电比容量分别达168.0、225.4、194.0 mAh·g-1, 放电比容量分别为138.4、165.8、157.7 mAh·g-1. 相似文献
162.
A series of A2Bi24Mo8X2O68 compounds, Ca2Bi24Mo8Cr2O68 (CBMC), Sr2Bi24Mo8Cr2O68 (SBMC), Pb2Bi24Mo8Cr2O68 (PBMC) and Ba2Bi24Mo8W2O68 (BBMW) have been synthesized by the solid-state method and characterized by single crystal X-ray diffraction. The compounds
index into the monoclinic P2/c system with a=11.687(4) ?, 5.784(2) ?, 24.728(9) ?, 101.911(6)°, Z=1; 11.673(6) ?, 5.775(3) ?, 24.670(2) ?, 101.757(8)°, Z=1; 11.638(3) ?, 5.790(1) ?, 24.655(6) ?, 101.716(4)°, Z=1 and 11.718(6) ?, 5.818(3) ?, 24.716(12) ?, 101.835(9)°, Z=1 for CBMC, SBMC, PBMC and BBMW, respectively. The structures were solved by direct methods and refined to R indices of 0.081,
0.065, 0.080 and 0.079 respectively. These compounds are isostructural with Bi26Mo10O69 and the structure consists of columns of [Bi12O14] along the b-axis, surrounded by Mo/Cr/WO4 tetrahedra. a.c. impedance studies indicate higher values of ionic conductivity for the tungsten-substituted compounds.
Supplementary material
The crystal data of CBMC, SBMC, PBMC and BBMW have been deposited at the Fachinformationszentrum Karlsruhe (FIZ) with the
numbers CSD 415143, CSD 415145, CSD 415144 and CSD 415142, respectively. 相似文献
163.
桑蚕丝素蛋白初始结构对其矿化作用的影响 总被引:4,自引:0,他引:4
以碱金属离子诱导桑蚕丝素蛋白溶液发生构象转变, 研究了蛋白质初始结构对其矿化作用的影响. FT-IR, XRD和SEM等测试结果显示, 未经任何处理的桑蚕丝素蛋白溶液矿化后形成片状复合物, 其无机相以二水磷酸氢钙(DCPD)为主; 而经过K+和Na+金属离子处理后, 桑蚕丝素溶液的结构由无规线团/螺旋构象向β-折叠发生转变, 矿化后成纤维状, 并相互结合呈现纳米级的三维多孔结构, 其无机相以热力学稳定的羟基磷灰石(HA)为主. 可以认为, 丝素蛋白结构转化为较伸展的β-折叠后, 使得更多的亲水基团暴露在外面, 在丝素蛋白分子不断凝聚成纤过程中, HA结晶快速生长并附着在这些微纤上, 最终形成纤维状的丝素蛋白/HA复合物. 该结果为阐明蛋白质的生物矿化过程及其调控机理提供了理论依据, 同时可以从矿化复合物的形成来反映这些微量元素可能对骨组织形成的影响, 为临床骨组织的修复提供一定的参考. 相似文献
164.
Stability constant for mercury binding by commercial and natural humic acids (HA) were determined using a new potentiometric mercury(II) sensor based on dithiosalicylic acid modified carbon paste electrode. The sensor present a high selective and sensitive response to mercury(II) ions, and a low detection limit of 1.8×10?8 M. The potentiometric titrations curves of humic acids against mercury(II) ions were modeled. For 1.00×10?7 to 3.00×10?4 M mercury(II) ion concentration levels the results are consistent with the presence of two different binding sites in the humic acid macromolecule. The strongest binding sites (log K1 ranging from 10.1 to 6.8) are probably due to interaction with carboxylic acid and amine groups in the molecule, whereas weakest binding sites (log K2 ranging from 8.8 to 4.5) can be associated to phenolic groups. 相似文献
165.
In aqueous H2SO4, Ce(IV) ion oxidizes rapidly Arnold's base((p-Me2NC6H4)2CH2, Ar2CH2) to the protonated species of Michler's hydrol((p-Me2NC6H4)2CHOH, Ar2CHOH) and Michler's hydrol blue((p-Me2NC6H4)2CH+, Ar2CH+). With Ar2CH2 in excess, the rate law of the Ce(IV)-Ar2CH2 reaction in 0.100 M H2SO4 is expressed -d[Ce(IV)]/dt = kapp[Ar2CH2]0[Ce(IV)] with kapp = 199 ± 8M?1s?1 at25°C. When the consumption of Ce(IV) ion is nearly complete, the characteristic blue color of Ar2CH+ ion starts to appear; later it fades relatively slowly. The electron transfer of this reaction takes place on the nitrogen atom rather than on the methylene carbon atom. The dissociation of the binuclear complex [Ce(III)ArCHAr-Ce(III)] is responsible for the appearance of the Ar2CH+ dye whereas the protonation reaction causes the dye to fade. In highly acidic solution, the rate law of the protonation reaction of Michler's hydrol blue is -d[Ar2CH+]/dt = kobs[Ar2CH+] where Kobs = ((ac + 1)[H*] + bc[H+]2)/(a + b[H+]) (in HClO4) and kobs= ((ac + 1 + e[HSO4?])[H+] + bc[H+]2 + d[HSO4?] + q[HSO4?]2/[H+])/(a + b[H+] + f[HSO4?] + g[HSO4?]/[H+]) (in H2SO4), and at 25°C and μ = 0.1 M, a = 0.0870 M s, b = 0.655 s, c = 0.202 M?1s?1, d = 0.110, e = 0.0070 M?1, f = 0.156 s, g = 0.156 s, and q = 0.124. In highly basic solution, the rate law of the hydroxylation reaction of Michler's hydrol blue is -d[Ar2CH+]/dt = kOH[OH?]0[Ar2CH+] with kOH = 174 ± 1 M?1s?1 at 25°C and μ = 0.1 M. The protonation reaction of Michler's hydrol blue takes place predominantly via hydrolysis whereas its hydroxylation occurs predominantly via the path of direct OH attack. 相似文献
166.
The effect of low-energy ion bombardment on CD4/O2 and CF3X (X=F, Cl, Br) plasma etching has been assessed by applying controlled rf bias voltages on polystyrene (PS) and polymethylmethacrylate (PMMA) samples. In both cases ion bombardment has been found to have a chemical effect. In the case of CF4/O2 discharges, ion bombardment has been found to change the relative etching efficiency of different mixtures. In the case of CF3X plasmas, ion bombardment has been found to alter PMMA and PS etch rates in a different way. In particular, the ratios between CF4 and CF3X (X=Cl, Br) etch rates of PS have been found to decrease with increasing bias voltage. This effect has been tentatively attributed to an ion bombardment-induced enhancement of the reaction between the aromatic ring and halogen molecules formed in CF3Cl and CF3Br discharges. 相似文献
167.
G. Gousset M. Touzeau M. Vialle C. M. Ferreira 《Plasma Chemistry and Plasma Processing》1989,9(2):189-206
A simple kinetic model predicting the concentration of oxygen atoms, metastable singlet molecules O2(a
1) and negative ions O — in the positive column of a DC glow discharge is developed. The calculated O and O2(a
1) concentrations are compared to previously reported measurements for pressuresp=0.2–2 Torr and discharge currentsI=10–80 mA. The electron density calculated from the continuity equationj=n
e
e v
d agrees well with experiment. The rate coefficients for electron impact processes used in the balance equations of O, O2(a
1), and O– were taken from the literature as a function of the reduced electric fieldE/N forE/N=40–80 Td. A reasonable agreement is obtained between the model and the experiment with a set of 10 reactions for the production and destruction of the above-mentioned species 相似文献
168.
169.
Utilization of a spiropyran derivative in a polymeric film optode for selective fluorescent sensing of zinc ion 总被引:1,自引:0,他引:1
ZHANG Ying SHAO Na YANG Ronghua LI Ke’an LIU Feng CHAN Winghong & MO Tian . College of Chemistry Molecular Engineering Peking University Beijing China . Department of Chemistry Hong Kong Baptist University Hong Kong China 《中国科学B辑(英文版)》2006,49(3):246-255
Spiropyrans are the most studied families of func- tional materials due to their reversible structural con- version in response to external optical, chemical, and thermal stimulation[1]. Irradiation with ultraviolet light causes formation of an extended π-conjugation open form (merocyanine form) by heterolytic cleavage of the C (spiro)-O bond, which generates an intense ab- sorption in the visible region. Under the irradiating of visible light, the opened form will come back to the closed spi… 相似文献
170.
以铜离子为模板的褐藻酸凝胶对铜离子的选择性富集研究 总被引:2,自引:0,他引:2
以铜离子为模板,制备了褐藻酸凝胶(Cu-alginate),通过吸附实验及过柱渗滤实验,试验了该吸附剂对铜离子的选择性吸附性能,并且采用该吸附剂富集了自来水中微量的Cu^2 ,结合原子吸收法测定了水样中Cu^2 的含量。结果表明:该吸附剂对Cu^2 有较高的选择性吸附性能,显著优于一些化学合成铜离子模板缩聚物及非铜模板褐藻酸凝胶(如Ca-alginate),非重金属离子(如K^ 、Na^ 、Ca^2 )及某些重金属离子(如Ni^2 、Cd^2 )等对Cu^2 的吸附均不产生明显干扰。用该吸附剂富集水中的微量铜离子,回收率可达97.7%。 相似文献