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921.
Melissa A. Milkie Marybeth J. Mattingly Kei M. Nomaguchi Suzanne M. Bianchi John P. Robinson 《Journal of marriage and the family》2004,66(3):739-761
Policy makers, parents, and the public are concerned with perceived declines in parents’ time with children. Data from two national surveys (N = 1,159 and N = 821) used in this study show that nearly half of parents report feeling too little time with children. Work hours are strongly related to these feelings, even controlling for time spent with children, and explain why fathers more than mothers feel time strain. For fathers, those whose youngest child is an adolescent feel more strain than similarly situated mothers. Controlling for work hours, single parents are not more likely than married parents to feel that they spend insufficient time with children. 相似文献
922.
Julian D. Taylor Arnas P. Verbyla 《Australian & New Zealand Journal of Statistics》2006,48(4):465-476
Elimination of a nuisance variable is often non‐trivial and may involve the evaluation of an intractable integral. One approach to evaluate these integrals is to use the Laplace approximation. This paper concentrates on a new approximation, called the partial Laplace approximation, that is useful when the integrand can be partitioned into two multiplicative disjoint functions. The technique is applied to the linear mixed model and shows that the approximate likelihood obtained can be partitioned to provide a conditional likelihood for the location parameters and a marginal likelihood for the scale parameters equivalent to restricted maximum likelihood (REML). Similarly, the partial Laplace approximation is applied to the t‐distribution to obtain an approximate REML for the scale parameter. A simulation study reveals that, in comparison to maximum likelihood, the scale parameter estimates of the t‐distribution obtained from the approximate REML show reduced bias. 相似文献
923.
924.
Momentum and the growth-free segment of a population 总被引:1,自引:0,他引:1
In the scenario of a sudden drop in fertility to replacement level. Preston (1986) argued that the population segment under age T, the length of generation, remained growth-free. Here we first present a new relationship for the momentum of any observed population as the ratio of 1) the proportion of the observed population under the mean age at childbearing to 2) the proportion of its life table population under that mean age. We then use that relationship to demonstrate Preston's approximation. Growth factors for other population segments are also presented. When the initial population is stable, momentum can be approximated as a function of the net reproduction rate alone. 相似文献
925.
A sample of 1,004 eighth and tenth grade students in twenty-three small Central/East Texas communities was assessed to determine 1) their perception of the number of their friends who use drugs, 2) the amount of information they received about drugs from their friends, and 3) the connection between those perceptions and drug use. A multiple regression model which included grade, gender, the degree to which friends are perceived to use drugs and the amount of information about drugs received from friends explained 39 percent of the variance in the degree to which rural adolescents were involved in drug use. An item specific analysis of the subcomponents of these composite variables explained 44 percent of the variance in the degree to which rural adolescents were involved in drug use. This same four-factor model accurately classified over 81 percent of non-drug-users and 67 percent of users using discriminant analysis. Students who perceived a higher degree of drug use among their friends and who received more information about drugs from their friends used drugs more frequently. Lower marijuana use in these rural areas as compared to the nation, both as a peer perception and as a fact, may protect these students to a degree from broader patterns of drug use. The findings of this study support the theory that peer pressure is related to drug abuse, even in rural areas. 相似文献
926.
Clearly, the necessary changes in the law and culture will not come easily or quickly. But, transcending all forms of these
labor market segments is a set of concerns that arguably should spur a search for common ground between labor and management.
The proliferation of automated technologies, together with the continuing impact of foreign competition with cheap labor markets,
has led some to predict that, over the next quarter century, we will witness the elimination of the blue-collar, mass assembly-line
worker from the production process.14
Moreover, the theory that those losing jobs in the manufacturing sector will be generally absorbed into the service sector
is losing currency as it is becoming clear that service jobs are, themselves, not invulnerable either to offshore outsourcing
(e.g., telephone operators, data processors) or to automated technology (e.g., bank tellers, office secretaries).
Nor is it realistic to expect the new “knowledge sector” to absorb more than a fraction of the unemployed and underemployed
casualties of this transformation. As a result, the widening gap between the haves and have nots will only continue to grow.
As the trend accelerates, certain possibilities for a labor-management accommodation emerge. For one thing, although corporations
may be enjoying short-term gains from present wage stagnation, downsizing, outsourcing, and casting off of permanent employees,
the longer term effects include a work force with considerably diminished consumer purchasing power. In some industries, corporations
are already acknowledging the adverse effects of this trend.
Furthermore, as employers are contributing into pension funds on behalf of fewer and fewer “employees,” the forced savings
pool that has for many years constituted a primary financing source of capital investments in our economy, will gradually
be depleted.15
At the same time as employers are coming face to face with the disadvantages of the union-free environment they have so long
sought, employers are also rediscovering the contributions to productivity, quality, and efficiency that can be gained from
a truly empowered work force with an independent voice in the workplace. All of this should lead an enlightened management
to place less currency on resisting unionization and other legitimate forms of independent employee representation, and to
join labor in advocating strong labor standards and effective labor law for all four of the labor market segments that exist
today and will exist tomorrow.
The authors wish to convey their deep appreciation for the invaluable contributions to this paper made by David Silberman
of Bredhoff & Kaiser and Craig Becker, Associate General Counsel, Service Employees International Union. Another version of
this paper was published in Labor Lawyer. 相似文献
927.
928.
929.
The ratio of a country's foreign trade (i.e., exports plus imports) to its GNP has a known tendency to decrease with country size. Previous studies have used a single year's data; but trade fluctuates greatly from year to year. This paper makes available a compilation of 1953–1972 export/GNP and import/GNP figures for 110 countries. The average import/GNP figure is found to correlate strongly with population size; the simple expression, Imports/GNP = 40 , applies, within a factor of 2, in 94% of cases. No correlation with development level can be seen. The United States data throughout its history (1799–1972) follow the same inverse cube root pattern, but with a constant of 20 instead of 40. Correlation is much poorer in the case of export/GNP ration. Export and import figures are only marginally correlated to each other. 相似文献
930.