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71.
焦炉煤气还原硫酸钠制硫化钠的研究 总被引:3,自引:0,他引:3
在固定床反应器内600~700℃的温度范围研究了焦炉煤气还原硫酸钠制硫化钠的反应速率和影响因素,在固定床内随着温度的提高,反应速率增大,并能达到较高的转化率.温度低于680℃,表现为催化反应,Fe2O3是活性较高的催化剂;在700℃以上表现为非催化反应。焦炉煤气中氢气的浓度和硫酸钠的颗粒直径对反应有一定的影响.在反应器内只要控制合适条件,往硫酸钠中加入脂肪酸的钠盐可以避免烧结,并能获得更高的反应速率。 相似文献
72.
陈丹英 《榆林高等专科学校学报》2005,15(1):52-55,59
依据国际法,主权国家可以对危害国际社会共同利益的国际罪行行使普遍管辖权。但是,从以往的国际实践来看,这种间接管辖的方式效果不尽人意。特别是对某些特定的国际罪行,如战争罪,侵略罪,种族灭绝罪,危害人类罪等等。在国际刑事法院建立之后,这些国际人道法中的罪行在法定条件下可以由国际刑事法院直接管辖。国际刑事法院必须尊重国内法院的管辖权,并符合相应的条件。本文试图讨论2003年的美伊战争中是否存在违反国际人道法的行为,这些行为是否可成为国际刑事法院管辖的对象。 相似文献
73.
明星制:中国影视业发展的有效途径 总被引:1,自引:0,他引:1
明星制是好莱坞电影工业化和社会化的重要标志。新世纪以来的中国电影电视业已走向产业化发展道路,中国明星制的建立完善已成为不可回避的问题。明星制中的明星打造、追星族的社会心理、明星双面效应以及中国本土明星制的完善健全等问题都值得我们探讨研究。 相似文献
74.
Point processes are the stochastic models most suitable for describing physical phenomena that appear at irregularly spaced
times, such as the earthquakes. These processes are uniquely characterized by their conditional intensity, that is, by the
probability that an event will occur in the infinitesimal interval (t, t+Δt), given the history of the process up tot. The seismic phenomenon displays different behaviours on different time and size scales; in particular, the occurrence of
destructive shocks over some centuries in a seismogenic region may be explained by the elastic rebound theory. This theory
has inspired the so-called stress release models: their conditional intensity translates the idea that an earthquake produces
a sudden decrease in the amount of strain accumulated gradually over time along a fault, and the subsequent event occurs when
the stress exceeds the strength of the medium. This study has a double objective: the formulation of these models in the Bayesian
framework, and the assignment to each event of a mark, that is its magnitude, modelled through a distribution that depends
at timet on the stress level accumulated up to that instant. The resulting parameter space is constrained and dependent on the data,
complicating Bayesian computation and analysis. We have resorted to Monte Carlo methods to solve these problems. 相似文献
75.
Cathy W. S. Chen F. C. Liu Mike K. P. So 《Australian & New Zealand Journal of Statistics》2008,50(1):29-51
To capture mean and variance asymmetries and time‐varying volatility in financial time series, we generalize the threshold stochastic volatility (THSV) model and incorporate a heavy‐tailed error distribution. Unlike existing stochastic volatility models, this model simultaneously accounts for uncertainty in the unobserved threshold value and in the time‐delay parameter. Self‐exciting and exogenous threshold variables are considered to investigate the impact of a number of market news variables on volatility changes. Adopting a Bayesian approach, we use Markov chain Monte Carlo methods to estimate all unknown parameters and latent variables. A simulation experiment demonstrates good estimation performance for reasonable sample sizes. In a study of two international financial market indices, we consider two variants of the generalized THSV model, with US market news as the threshold variable. Finally, we compare models using Bayesian forecasting in a value‐at‐risk (VaR) study. The results show that our proposed model can generate more accurate VaR forecasts than can standard models. 相似文献
76.
Michael S. Rendall Ryan Admiraal Alessandra DeRose Paola DiGiulio Mark S. Handcock Filomena Racioppi 《Statistical Methods and Applications》2008,17(4):519-539
In non-experimental research, data on the same population process may be collected simultaneously by more than one instrument.
For example, in the present application, two sample surveys and a population birth registration system all collect observations
on first births by age and year, while the two surveys additionally collect information on women’s education. To make maximum
use of the three data sources, the survey data are pooled and the population data introduced as constraints in a logistic
regression equation. Reductions in standard errors about the age and birth-cohort parameters of the regression equation in
the order of three-quarters are obtained by introducing the population data as constraints. A halving of the standard errors
about the education parameters is achieved by pooling observations from the larger survey dataset with those from the smaller
survey. The percentage reduction in the standard errors through imposing population constraints is independent of the total
survey sample size. 相似文献
77.
The phenotype of a quantitative trait locus (QTL) is often modeled by a finite mixture of normal distributions. If the QTL effect depends on the number of copies of a specific allele one carries, then the mixture model has three components. In this case, the mixing proportions have a binomial structure according to the Hardy–Weinberg equilibrium. In the search for QTL, a significance test of homogeneity against the Hardy–Weinberg normal mixture model alternative is an important first step. The LOD score method, a likelihood ratio test used in genetics, is a favored choice. However, there is not yet a general theory for the limiting distribution of the likelihood ratio statistic in the presence of unknown variance. This paper derives the limiting distribution of the likelihood ratio statistic, which can be described by the supremum of a quadratic form of a Gaussian process. Further, the result implies that the distribution of the modified likelihood ratio statistic is well approximated by a chi-squared distribution. Simulation results show that the approximation has satisfactory precision for the cases considered. We also give a real-data example. 相似文献
78.
79.
80.
Gayane Novikova 《Transition Studies Review》2004,11(3):213-223
The collapse of the USSR was accompanied by transformation of the South Caucasian latent ethnopolitical conflicts into local wars. Today the situation in the area of the conflicts is “neither war, nor peace”. Three unresolved conflicts of the South Caucasus can be considered as one of the most serious obstacles for establishing a regional security system.The article gives the general characteristics of these conflicts, the trends of their development, taking into account the time factor, and analyzes the behavioral models of the main players – de jure recognized and unrecognized de facto states of the South Caucasus. The basic objective of the main players should be to keep the situation on a level preventing the resumption of the armed conflicts. The attempts of forced resolution of the conflicts are fraught with destabilization of the situation not only in the area of any of these conflicts but in the whole region. 相似文献