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981.
J. Pill J. Aufenanger K. Stegmeier F. H. Schmidt D. Müller 《Fresenius' Journal of Analytical Chemistry》1987,327(5-6):558-560
Summary The investigation methods of the action of xenobiotics on sterol biosynthesis from 14C-acetate in rat hepatocyte cultures can be developed, with regard to extraction using Extrelut and the separation of the sterol pattern by thin-layer chromatography, in such a way that they are suitable for wider application, e.g., screening. Good visualisation and recognition of changes in the sterol pattern are possible using autoradiography of the thin-layer chromatogram.
Dedicated to Dr. E. Roesch on occasion of his 65th birthday 相似文献
Dünnschicht-Chromatographie von radioaktiv markiertem Cholesterin und Vorstufen aus biologischem Material. Eine einfache und empfindliche Methode zur Untersuchung einer Beeinflussung des Sterolbiosynthesewegs
Dedicated to Dr. E. Roesch on occasion of his 65th birthday 相似文献
982.
983.
984.
应用马尔科夫状态转移链的作战航空综合体效能评估 总被引:1,自引:0,他引:1
文章阐述了作战航空综合体的相关概念及组成,应用马尔科夫状态转移链建立了作战航空综合体完成典型作战任务时的数学模型,确定了作战效能的评估指标,最后通过具体算例检验了模型的正确性和可行性. 相似文献
985.
氟氧化物陶瓷的多谱线上转换发光 总被引:1,自引:0,他引:1
以氧化硅、氟化铅为基质制备了Er3 :Yb3 共掺杂氟氧化物陶瓷 ,X 射线分析表明陶瓷中存在着 β PbF2 晶相 ,沉积在其中的稀土离子由于具有很低的无辐射跃迁几率而显示出良好的上转换性能。Er3 ,Yb3 离子之间存在的多种能量传递通道 ,导致稀土离子十分丰富的上转换谱线的出现。 相似文献
986.
水合乙酸锌脱水反应的动力学 总被引:3,自引:0,他引:3
用等温热重法和非等温热重法研究了Zn(CH3COO) 2·2H2 O的脱水反应 .在 61.1、62 .8、66.2、69.9℃下的等温热重数据 ,由等转化率下的lnt=E/RT +ln[g(α) /A]进行拟合 ,确定了活化能的大小 ;升温速率为 10℃ /min的非等温热重曲线显示 ,Zn(CH3COO) 2·2H2 O的脱水反应发生在 71~ 10 2℃间 ,其数据通过Doyle Zsako法进行拟合 ,以线性相关系数为判据 ,并结合等温热分析拟合结果 ,得到该脱水反应的积分动力学模式函数g(α) =[-ln( 1-α) ]2 / 3、活化能E =10 0 .8kJ/mol、指前因子ln(A/s-1) =3 6.0 9、动力学补偿效应方程为lnA =0 .3 3 3 9E + 2 .0 10 . 相似文献
987.
T. V. Ramakrishnan H. R. Krishnamurthy S. R. Hassan G. Venketeswara Pai 《Journal of Chemical Sciences》2003,115(5-6):767-774
Manganites of the LA1−x
Ca
x
MnO3 family show a variety of new and poorly understood electronic, magnetic and structural effects. Here we outline a new approach
recently proposed by us, where we argue that due to strong Jahn-Teller (JT) coupling with phonons the twofold degeneratee
g
states at the Mn sites dynamically reorganize themselves into localised, JT polaronsl with exponentially small inter-site hopping, and band-like, nonpolaronic statesb, leading to anew 2-band model for manganites which includes strong Coulomb and Hund’s couplings. We also discuss some results from a dynamical mean-field theory treatment
of the model which explains quantitatively a wide variety of experimental results, including insulator-metal transitions and
CMR, in terms of the influence of physical conditions on the relative energies and occupation of thel andb states. We argue that this microscopic coexistence of the two types of electronic states, and their relative occupation and
spatial correlation is the key to manganite physics.
Dedicated to Professor C N R Rao on his 70th birthday 相似文献
988.
Summary A screening model (CISP) is presented for the calculation of maximum predicted concentrations from a single point source,
which is particularly useful in situations where on-site meteorological measurements are limited or unavailable. CISP utilizes
an analytical solution of the advection diffusion equation which is non-Gaussian in form. CISP performance in evaluating maximum
ground-level concentrations was compared with that of the Environmental Protection Agency (EPA) Regulatory PTPLU2 Gaussian
model. 相似文献
989.
H. W. Wenz W. J. Lichtenberg H. Katterwe 《Fresenius' Journal of Analytical Chemistry》1991,341(3-4):155-165
Summary When a shot is fired, the projectile and the cartridge case are released from the weapon, as well as components of the priming charge and propellant, the so-called powder-gunshot residues. In order to solve firearm offences, it is therefore very important to determine the topography of trace-bearing areas on the bullet and the cartridge case, as well as the chemical composition of gunshot residue particles. Gunshot residue particles are made visible with the scanning electron microscope (SEM) and are analysed by means of energy-dispersive X-ray spectroscopy (EDXS) and lately also by means of wavelength-dispersive X-ray spectroscopy (WDXS). In addition to this, analyses of these particles are displayed by means of Auger electron spectroscopy (AES) and secondary ion mass spectroscopy (SIMS) and depth profiles are prepared. To determine the local distributions of gunshot residue elements with regard to their quantity, the direct Zeeman atomic absorption spectroscopy (DZ-AAS) is employed. Besides the determination of the chemical composition, the topography of the trace-bearing areas on the bullet and cartridge case plays an important part. For the detection of these surfaces, light optical and electron-optical methods are employed. Moreover, the use of opto-electronical testing systems has been attracting more and more attention recently. 相似文献
990.
The existence and semiclassical limit of the solution to one-dimensional transient quantum drift-diffusion model in semiconductor
simulation are discussed. Besides the proof of existence of the weak solution, it is also obtained that the semiclassical
limit of this solution solves the classical drift-diffusion model. The key estimates rest on the entropy inequalities derived
from separation of quantum quasi-Fermi level. 相似文献