全文获取类型
收费全文 | 7200篇 |
免费 | 1352篇 |
国内免费 | 1213篇 |
专业分类
化学 | 5944篇 |
晶体学 | 80篇 |
力学 | 383篇 |
综合类 | 83篇 |
数学 | 787篇 |
物理学 | 2488篇 |
出版年
2024年 | 7篇 |
2023年 | 146篇 |
2022年 | 211篇 |
2021年 | 281篇 |
2020年 | 355篇 |
2019年 | 407篇 |
2018年 | 303篇 |
2017年 | 280篇 |
2016年 | 396篇 |
2015年 | 405篇 |
2014年 | 452篇 |
2013年 | 573篇 |
2012年 | 701篇 |
2011年 | 667篇 |
2010年 | 415篇 |
2009年 | 426篇 |
2008年 | 459篇 |
2007年 | 369篇 |
2006年 | 362篇 |
2005年 | 322篇 |
2004年 | 281篇 |
2003年 | 247篇 |
2002年 | 330篇 |
2001年 | 268篇 |
2000年 | 167篇 |
1999年 | 150篇 |
1998年 | 128篇 |
1997年 | 74篇 |
1996年 | 82篇 |
1995年 | 62篇 |
1994年 | 64篇 |
1993年 | 50篇 |
1992年 | 80篇 |
1991年 | 50篇 |
1990年 | 50篇 |
1989年 | 30篇 |
1988年 | 22篇 |
1987年 | 23篇 |
1986年 | 23篇 |
1985年 | 12篇 |
1984年 | 8篇 |
1983年 | 11篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1971年 | 1篇 |
1959年 | 2篇 |
1957年 | 2篇 |
1936年 | 3篇 |
排序方式: 共有9765条查询结果,搜索用时 15 毫秒
991.
Wen CZ Hu QH Guo YN Gong XQ Qiao SZ Yang HG 《Chemical communications (Cambridge, England)》2011,47(21):6138-6140
Single-crystalline TiOF(2) crystals with cubical morphology were prepared via a facile solvothermal method and their transformation to anatase TiO(2) under different calcination conditions such as pure argon, moist argon and pure hydrogen sulfide (H(2)S) was explored by using XRD/Raman/UV-Vis/SEM/TEM/SAED. The non-metal sulfur doping was successfully fulfilled and the doped TiO(2) microcubes showed the best photocatalytic H(2) evolution property. 相似文献
992.
West NP Cergol KM Xue M Randall EJ Britton WJ Payne RJ 《Chemical communications (Cambridge, England)》2011,47(18):5166-5168
The first targeted inhibitors of an essential M. tuberculosis cell wall lipase, Rv3802c, are described. Lead compounds exhibited nanomolar inhibition of the enzyme, and encouraging antibacterial activity against M. tuberculosis in vitro, supporting Rv3802c as a novel TB drug target. 相似文献
993.
Nearly monodispersed magnetic Fe(3)O(4)@DFUR-LDH submicro particles containing the anticancer agent DFUR were prepared via a coprecipitation-calcination-reconstruction strategy of LDH materials over the surface of Fe(3)O(4) particles, and present well-defined core-shell structure, strong magnetization and obvious magnetically controlled drug delivery and release properties. 相似文献
994.
Qi H Bi N Chen Y Zheng X Zhang H Wang X Chen Y Tian Y 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,81(1):769-773
The DNA was determined based on resonance light scattering (RLS) spectrometry and the localized surface plasmon resonance. The gold bipyramids were used as the probes and synthesized by a seed-mediated method. Cetyltrimethylammonium bromide was used as stabilizing agent. DNA can be bound to the gold bipyramids due to electrostatic interaction and aggregates, which results in a strong enhancement of the RLS intensity. Under the optimal conditions, the intensity of RLS is directly proportional to the concentration of DNA in the range from 0.1 to 2.0 μg mL(-1). 相似文献
995.
Xue F Liang J Han H 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,83(1):348-352
A non-cadmium and water-soluble Mn-doped ZnO(x)S(1-x) QDs was synthesized with denatured bovine serum albumin (dBSA) as stabilizer under nitrogen atmosphere, and the as-prepared products were characterized by X-ray powder diffraction (XRD), UV-vis absorption spectroscopy, fluorescence (FL) emission spectroscopy, high resolution transmission electronmicroscopy (HRTEM) and Raman spectrum. XRD patterns indicate that the Mn-doped ZnO(x)S(1-x) QDs have a zinc-blende structure, and that manganese emerges in the form of divalent manganese (Mn(2+)) and trivalent manganese (Mn(3+)) (the intermediate of the reaction). The size of Mn-doped ZnO(x)S(1-x) QDs is about 3.2±0.7 nm according to HRTEM imaging. The FL spectra reveal that the Mn-doped ZnO(x)S(1-x) QDs have two distinct emission bands: the defect-related emission and the Mn(2+)-related emission, which exhibit a competing process. A good FL signal of the transition of Mn(2+) ((4)T(1)-(6)A(1)) is observed when the doping amounts are 1.0% and 20% respectively, and the as-prepared solutions are stable for more than 6 months at 4°C. This method has the advantages of good stability and environment-friendly stabilizer, for involving no heavy metal ions or toxic reagents. 相似文献
996.
Zhang HM Zhou QH Xue MG Wang YQ 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(3):1018-1022
The interaction between triphenyltin (TPT) and humic acid (HA) was investigated using UV-vis and fluorescence spectra techniques. The experimental results showed that the fluorescence quenching of HA by TPT was a result of the interaction of TPT with HA. The binding constant K(b) and corresponding thermodynamic parameters were measured at different temperatures. The binding of TPT molecule to HA is a spontaneous molecular interaction procedure in which entropy increased and Gibbs free energy decreased. Hydrophobic interaction force plays a major role in stabilizing the TPT-HA complex. The three-dimensional fluorescence contour spectra revealed that TPT could enter into the hydrophobic cavities in some domain of HA. 相似文献
997.
Zheng X Chen Y Bi N Qi H Chen Y Wang X Zhang H Tian Y 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,81(1):578-582
Based on the surface-enhanced Raman scattering (SERS) sodium 2-mercaptoethanesulfonate (mesna) was determined using unmodified gold colloid as the probe. The Raman scattering intensity was obviously enhanced in the presence of sodium chloride. The influence of experimental parameters, such as incubation time, sodium chloride concentration and pH value on SERS performance was examined. Under the optimum conditions, the SERS intensity is proportional to the concentration of mesna in the range of 9.0×10(-8) to 9.0×10(-7) mol/L and detection limit (S/N=3) is 1.16×10(-8) mol/L. The corresponding correlation coefficient of the linear equation is 0.996, which indicates that there is a good linear relationship between SERS intensity and mesna concentration. The experimental results indicate that the proposed method is a viable method for determination of mesna. The real samples were analyzed and the results obtained were satisfactory. 相似文献
998.
Thermal behavior of 1,2,3-triazole nitrate 总被引:1,自引:0,他引:1
Liang Xue Feng-Qi Zhao Xiao-Ling Xing Zhi-Ming Zhou Kai Wang Hong-Xu Gao Jian-Hua Yi Si-Yu Xu Rong-Zu Hu 《Journal of Thermal Analysis and Calorimetry》2011,104(3):999-1004
The thermal decomposition behaviors of 1,2,3-triazole nitrate were studied using a Calvet Microcalorimeter at four different
heating rates. Its apparent activation energy and pre-exponential factor of exothermic decomposition reaction are 133.77 kJ mol−1 and 1014.58 s−1, respectively. The critical temperature of thermal explosion is 374.97 K. The entropy of activation (ΔS
≠), the enthalpy of activation (ΔH
≠), and the free energy of activation (ΔG
≠) of the decomposition reaction are 23.88 J mol−1 K−1, 130.62 kJ mol−1, and 121.55 kJ mol−1, respectively. The self-accelerating decomposition temperature (T
SADT) is 368.65 K. The specific heat capacity was determined by a Micro-DSC method and a theoretical calculation method. Specific
heat capacity equation is
C\textp ( \textJ mol - 1 \text K - 1 ) = - 42.6218 + 0.6807T C_{\text{p}} \left( {{\text{J mol}}^{ - 1} {\text{ K}}^{ - 1} } \right) = - 42.6218 + 0.6807T (283.1 K < T < 353.2 K). The adiabatic time-to-explosion is calculated to be a certain value between 98.82 and 100.00 s. The critical
temperature of hot-spot initiation is 637.14 K, and the characteristic drop height of impact sensitivity (H
50) is 9.16 cm. 相似文献
999.
1000.
Zhu J Xue M Zhao D Zhang M Duan L Qiu Y Cao T 《Angewandte Chemie (International ed. in English)》2011,50(52):12478-12482
You crack me up: A topographically patterned PDMS stamp was coated with thin metal film and swelled under organic vapor to induce the tunable cracking of the brittle film into metallic nanostructures (see SEM images, scale bars 1?μm). UV/Vis spectra, OLED efficiency, and SERS spectra demonstrate the fine controllability of the metallic nanostructures, the well-ordered and highly regulable surface plasmons, and the facile fabrication process. 相似文献