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排序方式: 共有46条查询结果,搜索用时 31 毫秒
1.
Statistics and Computing - Variable clustering is important for explanatory analysis. However, only few dedicated methods for variable clustering with the Gaussian graphical model have been... 相似文献
2.
Aging leads to significant losses in muscle mass, strength, and the ability to independently perform activities of daily living (ADL). Typically, standard resistance training (RT) has been used to reduce these losses in function by maintaining or even increasing muscle strength in older adults. Increasing strength does not necessarily, however, result in an increase in the ability to perform ADL. There is now research suggesting that muscle power is more closely associated with the performance of ADL than muscle strength is, so training for muscle power might lead to more beneficial results in functional performance. This review of studies investigating the effect of training on ADL performance in older adults indicated that standard RT is effective in increasing strength in older adults, but power training that contains high-velocity contractions might be a more optimal means of training older adults when the emphasis is on increasing the performance of ADL. 相似文献
3.
Models of Career Advancement in Organizations 总被引:1,自引:0,他引:1
4.
Ishida H 《The British journal of sociology》2001,52(4):579-604
This study examines intergenerational class mobility in Japan using cross-national comparisons with Western nations and cross-temporal comparisons of five national surveys conducted in postwar Japan. Cross-national comparisons highlight the similarity in relative mobility pattern between Japan and Western nations and at the same time the Japanese distinctiveness in absolute mobility rates especially regarding the demographic character of the Japanese manual working class. The results of cross-temporal comparisons of mobility pattern report some systematic trends in total mobility, inflow and outflow rates, reflecting the Japanese experience of late but rapid industrialization. The pattern of association between class origin and class destination, however, was stable in postwar Japan. It is therefore the combination of distinctive absolute mobility rates and similar relative mobility rates that characterizes the Japanese mobility pattern in comparison with the Western experience. Furthermore, Japan's distinctive pattern of postwar social mobility is characterized by a combination of rapidly changing absolute mobility rates and comparatively stable relative mobility rates. 相似文献
5.
This paper questions whether personal income comparison explains the distributive gap between income and class identification by exploring the following two issues: empirical validity of income comparison as the determinant of class identification, and theoretical validity of income comparison for the distributive gap. For the first issue, we conduct a statistical analysis using data from the Social Stratification and Social Mobility surveys (1975–2005), and the Stratification and Social Psychology-I survey (2010). We find that the criteria for choosing reference groups changed historically from residential proximity to occupational equality. In addition, income comparison with sensitive to lower-income possessors and a distorted perception of income difference significantly affected class identification, except for the year of 1985. The simulation analysis employed to examine the second issue clarified that income comparison with the above-mentioned features yields a less skewed distribution compared to that of class identification. The data also indicates that the empirical conditions of income are satisfied for realization of this result. Thus, we could ascertain empirical and theoretical validity of income comparison as explanation for the distributive gap between income and class identification. 相似文献
6.
In sequencing problems for mixed-model assembly line in JIT production system, the Goal Chasing method (GC) is widely used for parts used leveling goal. The difference in assembly time of each product is not taken into consideration in the Goal Chasing method. Assembly time usually varies with product types. In recent years, the Time-Based Goal Chasing method (TBGC) has been proposed. The advantage of TBGC is to consider the influence of different assembly time of each product and idle time in production period. TBGC, however, has been only applied to single work station problems. In this paper, TBGC is applied to an assembly line problem with multiple work stations. Furthermore, the sequencing method and use of Simulated Annealing (SA) or Local Search (LS) for this problem are proposed. 相似文献
7.
8.
InMenida scotti aduts which mate during hibernation, we examined the effect of photoperiod on diapause induction in terms of the developmental
degree of reproductive organs and corpora allata. In a hibernating population, mating season and physiological changes related
to dipause were investigated. When newly emerged adults were reared under long- or short-day conditions, reservoir of the
ectodermal accessory gland and corpora allata in males developed, while the developments of ovary and corpora allata in females
were suppressed under both conditions. This suggests that diapause of this species is induced only in females independently
photoperiodic conditions during adult stage. In a hibernating population, mating was observed from early to late November
and from late March to early May. Observations of the development of reproductive organs and corpora allata suggest that diapause
is induced only in females in the former period, while both sexes are not in diapause in the latter period. 相似文献
9.
Kenji Fujisaki 《Researches on Population Ecology》1986,28(2):219-230
Summary Responses to nymphal density in the determination of wing form were compared between the offspring from brachypter x brachypter
crosses and those from macropter x macropter crosses of the oriental chinch bug,Cavelerius saccharivorus.
In the offspring from crosses between macropters, there was a strong tendency for macropters to increase to a rather high
level with increasing nymphal density in both sexes. In contrast to this, in the offspring from crosses between brachypters,
the appearance rate of macropters attained a maximum value in moderately crowded conditions and conversely decreased to a
lower level in more crowded conditions in both sexes. Thus density response patterns concerning the determination of wing
form were quite different between the offspring from different crosses in the wing form, indicating that there is a genetic
basis underlying wing polymorphism in this species.
As for the body size of emerged adults, macropters tended to be larger than brachypters in the same crowded condition. Moreover,
the rate of decrease of body size with nymphal density was lower in the offspring from crosses between macropters than in
the offspring from crosses between brachypters. This indicated that the former offspring are more tolerant of nymphal crowding
than the latter. The difference in such a tolerance against nymphal crowding between the offspring from different crosses
was considered to be related to the difference in the appearance of macropters in the crowded conditions between them. 相似文献
10.
Evaluation of the mortality impact of nationwide disease-prevention efforts is complicated by potential endogeneity: programme recipients may have unobserved characteristics that simultaneously make them both more likely to become recipients and more likely to survive as a result of other health practices. This population-based study assesses the mortality impact of a nationwide programme that distributed insecticide-treated nets (ITNs) to mothers of children aged 9-59 months in Togo. By comparing mortality rates before and after the programme according to households' eligibility status, we demonstrate that a one-time programme that restricts eligibility to households with a surviving child excludes some households with a high risk of child mortality. We then apply simultaneous estimation models to untangle the mortality impact of ITNs from the effects of unobserved confounders and show that among eligible households, living in a household with ITNs significantly reduces mortality for children aged 20-59 months, even after controlling for endogeneity. 相似文献