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261.
262.
α、β、γ、δ-四(4-三甲氨基苯基)卟啉与钌(Ⅲ)显色反应的研究 总被引:4,自引:0,他引:4
本文研究了α、β、γ、δ-四(4-三甲氨基苯基)卟啉(简称TAPP)和钌的显色反应。其最大的吸收波长位于436nm,表观摩尔吸光系数为5。25×10~5L·mol~(-1)·cm~(-1),钉的浓度在0~2.5μg/10ml范围内服从比尔定律,络合物的组成比为Ru:TAPP=1:1。该法用于合成矿样分析,结果满意。 相似文献
263.
We investigate the flocking conditions of a group coupling system with time delays, in which the communication between particles includes inter-group and intra-group interactions, and the time delay comes from the theory of moving object observation. As an effective model, we introduce a system of nonlinear functional differential equations to describe its dynamic evolution mechanism. By constructing two differential inequalities on velocity and velocity fluctuation from a continuity argument, and using the Lyapunov functional approach, we present some sufficient conditions for the existence of asymptotic flocking solutions to the coupling system, in which an upper bound of the delay allowed by the system is quantitatively given to ensure the emergence of flocking behavior. All results are novel and can be illustrated by using some specific numerical simulations. 相似文献
264.
Matthias Rösslein Sergio Rezzonico Roman Hedinger Marco Wolf 《Accreditation and quality assurance》2007,12(8):425-434
Various publications stress the importance of the repeatability (i.e. precision) of the calculation of the measurement of
uncertainty. We reveal by detailing an example from production control in the pharmaceutical industry that the effect of other
influence quantities should not be neglected, because their magnitude is even larger than the contribution of repeatability.
We review the role of repeatability within the calculation of measurement uncertainty for several common validation and day-to-day
measurement scenarios. They show that measurement models need to consider the measurement sequences of the various scenarios.
Otherwise the size and effect of the repeatability might be overestimated. At the end Monte Carlo simulations were used to
investigate the determination of the repeatability under certain restrictions. The simulation uncovered a significant bias
toward the common formula for calculating the standard deviation when it is based on a duplicated measurement of a sample.
Papers published in this section do not necessarily reflect the opinion of the Editors, the Editorial Board and the Publisher 相似文献
265.
I. Leito E. Koort Koit Herodes Ivari Kaljurand 《Accreditation and quality assurance》2002,7(4):159-162
The introduction of MiC (Metrology in Chemistry) into the Chemistry Curriculum at the University of Tartu using a two-stage
approach is described. As the first stage the topics of MiC are first touched at the beginning of the first analytical chemistry
lecture course in the 3rd semester. The emphasis there is on the measurement uncertainty (MU) and its practical estimation
(based on the ISO GUM approach). The main purpose of this is to make it clear from the beginning that MU is an integral part
of any measurement and to enable the students to estimate MU in the laboratory courses of analytical chemistry (3rd and 4th
semesters). As the second stage, MiC is treated in more detail in a dedicated course where also topics, such as reference
materials, interlaboratory comparisons, standardization, quality management, accreditation, etc are covered.
Received: 6 November 2001 Accepted: 6 December 2001 相似文献
266.
Lauri?Jalukse Ivo?LeitoEmail author Aleksei?Mashirin Toomas?Tenno 《Accreditation and quality assurance》2004,9(6):340-348
A procedure for the estimation of measurement uncertainty of dissolved oxygen (DO) concentration measurement based on the ISO approach is presented. It is based on a mathematical model that involves 14 input parameters. The uncertainty of DO concentration strongly depends on changes in experimental details (temperature difference between calibration and measurement, the time interval between calibration and measurement, etc.). The relative measurement uncertainty is, however, practically independent of the DO concentration itself. The uncertainty is the lowest if the calibration and the measurement are done at the same temperature and on the same day. A calculation tool is provided (in the form of a GUM Workbench file) for practitioners that can be used for uncertainty calculation of DO concentrations at very different experimental conditions.Electronic Supplementary Material The uncertainty calculation example is available as a GUM Workbench calculation file C_O2_meas.smu (GUM Workbench ver. 1.3.3, Metrodata GmbH) together with its data file Input_values.xls (MS Excel 97). For those users who do not have GUM Workbench, the full report of the GUM Workbench calculation is available as a PDF file C_O2_meas.pdf. This material is available via the Internet at . 相似文献
267.
运用浓度比较法, 对25 ℃时V-H2O体系进行热力学分析和电化学分析, 编程计算出各溶解组分浓度, 以及固相和液相、各固相间边界线, 确定固相区和液相区的位置. 在此基础上, 绘制出了总V浓度cT(V)=1.0×10-5 mol·L-1时V-H2O体系的溶解组分优势区域图和电势-pH图以及cT(V)=1.0×10-7 mol·L-1时V-H2O体系的电势-pH图. 电势-pH图结果表明在一定温度和压力下, 各相稳定区取决于体系中溶液态物质的总浓度. 随cT(V)的减小, 溶液稳定区增大, 各固相稳定区均不同程度减小. 相似文献
268.
An automated gas chromatographic subsystem for the provision of fast and reliable concentration profile data for distillation column control is presented. The subsystem consists of a gas chromatograph, equipment for sample conditioning and a PC/AT compatible computer communicating with the supervisory process computer. A fast separation time is obtained through the use of a liquid chromatographic packing material and a high pressure drop across the column. Preliminary results show separation times below 10 s for the water-methanol-isopropanol system. Peak areas are quantified by use of parameter estimation in the frequency domain, a method that does not demand complete peak separation. 相似文献
269.
Compliance with legal requirements: definition of limits, sampling and measurement uncertainty 总被引:1,自引:0,他引:1
Hermann Glaeser 《Accreditation and quality assurance》2002,7(10):388-391
In many cases compositional requirements for foodstuffs (e.g. limits for the fat, protein, dry matter, or water content) are
established by legislation. Adequate compliance testing is possible only if limits are clearly defined, taking measurement
and sampling uncertainty into consideration. Furthermore, decisions on compliance must be based on samples which reflect the
composition of the quantity to be evaluated. The resulting sample sizes are normally regarded by food inspection authorities
as being much larger than acceptable. Consequently, an alternative strategy should be developed. Autocontrol data (i.e. inspection
results obtained by the factory) in principle provide an adequate data basis for decisions on compliance. However, they must
be reliable and the food inspection authority must have access to these data on request. Using these data and on condition
that they show an approximate normal distribution, an inspection strategy based on arithmetic mean and standard deviation
can be developed. Reliable and transparent decisions on compliance can thus be made. In many cases an adequate verification
of food authenticity requires a comparison of raw material and product composition. Maximum acceptable differences, taking
the relevant sources of variation into consideration, have to be defined and should be used instead of limits.
Received: 17 April 2002 Accepted: 23 June 2002 相似文献
270.
This article deals with a linear stability analysis of electrodeposition. The surface energy is disregarded in order to focus on the possible effects of the finite width of the electric double layer and the finite electrode reaction rate upon the wavelength selection. It is found that in the absence of electroconvection the fastest growing perturbation mode is that with a wavelength equal to the geometric average of the Debye length and the reaction diffusion length, which is the ratio of diffusivity to the electrode reaction rate. This wavelength is one–two orders of magnitude greater than that selected by the capillarity mechanism based on the surface energy estimates. This shift of the selected wavelength towards long waves is enhanced by another order of magnitude by electroconvection in the regime of the nonequilibrium electroosmosis developing upon the emergence of the extended space charge. 相似文献