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41.
n维理想玻色气体性质的普遍描述 总被引:6,自引:4,他引:6
给出了在T>Tc和T<Tc情况下能谱为ε=ap^s的n维简并理想玻色色体的内能、熵、状态程和热容量和普遍表达式。指出存在两种类型的玻以-爱因斯坦凝聚。 相似文献
42.
Zhong Changyong 《数学年刊B辑(英文版)》1989,10(3):351-360
In this paper, the author extends Nevanlinna's second fundamental theorem and establishes the following inequality:
Let $\[p(s,u) = {A_v}(s){u^v} + {A_1}(s){u^{v - 1}} + \cdots + {A_0}(s)\]$
be an irreducible two-variable polynomial and $f(s)$ a transcendental entire function, then
$$\[(\nu - 1)T(r,f) < N(r,\frac{1}{{p(z,f(z))}}) + S(r,f)\]$$
with
$$\[S(r,f) = O(\log (rT(r,f)))n.e\]$$
where an. "n.e" means that the estimation holds for all large r with possibly an exceptional of finite measure when f is of infinite order. 相似文献
43.
The thermal isomerization of tricyclo[4.1.0.0(2,7)]heptane and bicyclo[3.2.0]hept-6-ene was studied using ab initio methods at the multiconfiguration self-consistent field level. The lowest-energy pathway for thermolysis of both structures proceeds through the (E,Z)-1,3-cycloheptadiene intermediate. Ten transition states were located, which connect these three structures to the final product, (Z,Z)-1,3-cycloheptadiene. Three reaction channels were investigated, which included the conrotatory and disrotatory ring opening of tricyclo[4.1.0.0(2,7)]heptane and bicyclo[3.2.0]hept-6-ene and trans double bond rotation of (E,Z)-1,3-cycloheptadiene. The activation barrier for the conrotatory ring opening of tricyclo[4.1.0.0(2,7)]heptane to (E,Z)-1,3-cycloheptadiene was found to be 40 kcal mol(-1), while the disrotatory pathway to (Z,Z)-1,3-cyclohetpadiene was calculated to be 55 kcal mol(-1). The thermolysis of bicyclo[3.2.0]hept-6-ene via a conrotatory pathway to (E,Z)-1,3-cycloheptadiene had a 35 kcal mol(-1) barrier, while the disrotatory pathway to (Z,Z)-1,3-cyclohetpadiene had a barrier of 48 kcal mol(-1). The barrier for the isomerization of (E,Z)-1,3-cycloheptadiene to bicyclo[3.2.0]hept-6-ene was found to be 12 kcal mol(-1), while that directly to (Z,Z)-1,3-cycloheptadiene was 20 kcal mol(-1). 相似文献
44.
in this paper, we characterize the automorphism groups of Toeplitz algebras oncertain strongly pseudoconvex domains of Cn, and obtain a generalized BDF theorem for aspecial kind of essential normal operator tupies. 相似文献
45.
Cu-Pd/MCM-22催化剂上二甲醚低温水解反应 总被引:1,自引:0,他引:1
考察了分子筛的类型、硅铝比及Cu和Pd改性对分子筛催化剂上二甲醚低温水解活性的影响. 结果表明,酸性的MCM-22和HZSM-5分子筛催化剂具有较高的二甲醚水解活性,且其活性随着分子筛硅铝比的增加而降低. 这表明分子筛的类型及酸性对催化剂性能有重要影响,具有超笼结构的MCM-22分子筛上B酸中心的良好可接近性,使得该分子筛催化剂的水解活性较相同硅铝比的HZSM-5分子筛高. 与改性前相比, Cu和Pd改性后的MCM-22催化剂显示出更高的二甲醚水解活性. 相似文献
46.
47.
Changyong Oh Lawan Sriphong Minjung Kim Hoeil Chung Panida Asavapichayont 《Journal of Raman spectroscopy : JRS》2011,42(3):445-451
We present a reliable and nondestructive analytical method for the determination of urea concentration in a pharmaceutical cream formulation using Raman spectroscopy. A pharmaceutical cream is a highly viscous emulsion; therefore, its composition and physical mixing could be inhomogeneous on a microscopic scale. The local environment around the urea could vary, which could influence the molecular vibrations of the urea molecule. As expected, when Raman spectra were collected by focusing the laser onto a tiny area (∼2–3 µm), the position of the urea band at 1003 cm−1 varied as a result of the microscopic inhomogeneity within the sample. Therefore, acquisition of Raman spectra representative of the entire sample rather than a localized portion of it is very important for the analysis of pharmaceutical creams. Based on the preliminary Raman mapping results of a urea cream, a sample area of at least 750 × 750 µm should be covered for reliable quantitative analysis. In this study, we used a wide‐area illumination scheme capable of covering a sample area of 28.3 mm2 for Raman spectral collection in order to ensure a reliable representative sample. In addition, to simplify the measurements, Raman spectra of urea creams in plastic bottles were directly collected without further sampling, and partial least squares regression was used for quantitative analysis. The urea concentrations were accurately determined despite the spectral collection being performed through plastic bottles. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
48.
Yuchen Huang Longbao Feng Yi Zhang Liumin He Changyong Wang Jiake Xu Jianping Wu Thomas Brett Kirk Rui Guo Wei Xue 《先进技术聚合物》2017,28(9):1107-1114
Chitosan (CHI) is a versatile biological material that is well known for its hemostatic properties. This preliminary study evaluated several self‐assembling hydrophobically modified chitosan (HM–CHI) sponges to determine their efficacy on hemostasis . Fourier transform infrared (FT‐IR) spectroscopy was used to determine the successful graft of dodecyl groups onto the nitrogen atoms of CHI molecules. A platelet aggregation assay revealed that HM–CHI accelerated the platelet aggregation rate. Fluorescence spectroscopy showed that the HM–CHI changed the structure of fibrinogen in blood. Activated partial thromboplastin time, prothrombin time, fibrinogen time, and thromboelastographic assays were used to explore the effect of HM–CHI on the autologous blood coagulation pathway. Finally, a hemostatic sponge was made with HM–CHI and freeze‐dried zeolite composite film and was applied to the rat femoral artery hemostasis model. A hemostasis time of 86 ± 5 sec was achieved, which was significantly better than the one composed with pure CHI. The experimental results of the HM–CHI hemostatic materials are inspiring and will encourage the research and development of such materials. HM–CHI may be a strong candidate as a safe and effective hemostatic material. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
49.
利用YAG激光抽运的染料激光器将钾原子由基态 4S双光子共振激发到 6S态 ,研究了钾原子 4S 6S双光子共振三光子电离的电离谱与温度、激光强度的关系 ,发现电离流的强度随着温度的升高而增强 ,当温度在 370℃附近时达到最大值 ,此时温度继续升高电离流强度减弱。在温度不变的情况下 ,电离流强度随着激光能量的增强而增强 ,当激光强度为 4 5× 10 5W /mm2 时到达最大值 ,继续增加激光强度 ,电离流强度趋于饱和。实验中观测到对应于 6S 4P的自发辐射 相似文献
50.
偶奇qs相干态的非经典特性 总被引:6,自引:1,他引:6
利用数值计算方法研究了q和s畸变对双参数形变偶奇qs相干态量子统计特性的委现偶奇qs相干态与通常的偶奇相干态有着显著不同的量子统计性质,压缩效应和反聚束效应均可在一定条件下的两种双参数畸变态中出现,偶奇qs相干态和通常偶奇相干态的差异随q值偏离1越大和s的取值越小而越大。 相似文献