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951.
Development and accuracy of projections of population and households in the united states 总被引:1,自引:1,他引:1
Jacob S. Siegel 《Demography》1972,9(1):51-68
The history of the official U. S. projections of population and house-holds in recent decades is briefly reviewed, with particular attention to methodology and the relation of the methodology to the accuracy of the projections. The introduction of the cohort-component procedure in the 1930’s opened the way for separate analysis of the trend of the components of births, deaths, and net immigration in connection with making population projections. As a further development, the period-fertility method of projecting births gave way in the 1960’s to the cohort-fertility method. Consideration is now being given to various methods involving parity-progression procedures. Some alternative methods and problems of measuring the accuracy of population projections are then considered. The percent “error” in the projected population growth, by components and age, and the range from high to low expressed as a percent should also be examined in addition to the percent “error” in the total population. However accuracy is measured, the projections made in the 1930’s and 1940’s were often wide of the mark, and those made in the 1950’s and 1960’s failed to anticipate the sharp changes which occurred, even though the actual figures usually fell within the range projected. Elaboration of projection methodology has not resulted in any great increase in the precision of the projections, largely because birth rates have fluctuated widely, and the fluctuations have proven difficult, if not impossible, to predict. The projections of households have had a roughly similar history, and the methods and problems of evaluation are somewhat similar. Their development has been characterized by the introduction of alternative and changing “headship” rates and increasing disaggregation of the data and procedures. The paper concludes with some generalizations based on U. S. experience. Although refinement of methods may contribute little to accuracy, accuracy is only one aspect of the usefulness of projections. The need for conditional projections and their analytical usefulness are such that there is no question that we should confidently continue to make them. 相似文献
952.
Abstract This research had two primary objectives: 1) to broaden the sociological construct of community attachment to incorporate both social and natural environment dimensions of attachment, and 2) to examine how variations in attachment relate to two dimensions of well‐being in natural amenity‐rich rural communities. The specific dimensions of well‐being measured are two important factors identified in previous research—collective action and perceptions of open communication. Factor analysis of fourteen measures of attachment indicated social attachment and attachment to the natural environment are distinct dimensions of the broader concept of community attachment. Participation in collective action and perceptions of open communication within a respondent's community explained only a small portion of the variance in levels of both social and natural environment attachment. Religious affiliation and length of residence were strongly associated with social attachment, supporting findings from previous empirical work. However, length of residence and religious affiliation were not statistically associated with levels of attachment to the natural environment, further reinforcing the distinction between the two dimensions of attachment. 相似文献
953.
K Smith H Hamerton S Hunt RJ Sargisson 《Kōtuitui : New Zealand Journal of Social Sciences Online》2016,11(1):1-10
Following the MV Rena grounding and oil spill in the Bay of Plenty, New Zealand in October 2011, the Māori community of Maketū were quick to respond to the arrival of oil on their beaches. They asserted their rangatiratanga by establishing their marae as a base and successfully coordinated a clean-up by more than 450 volunteers, feeding these volunteers every day. We interviewed 11 clean-up leaders and volunteers in Maketū to gather information about how the oil spill affected people in the community and how they ensured the success of their clean-up efforts. Many volunteers returned to help with the clean-up day after day over several weeks. Concepts of kaitiakitanga and manaakitanga underpinned the work of the Maketū clean-up organisers. Participants attributed the success of the Maketū clean-up to the speed with which they responded, the support they received from their community and local businesses, and their local knowledge. 相似文献
954.
S. R. Lipsitz J. Ibrahim & G. Molenberghs 《Journal of the Royal Statistical Society. Series C, Applied statistics》2000,49(3):287-296
We analyse longitudinal data on CD4 cell counts from patients who participated in clinical trials that compared two therapeutic treatments: zidovudine and didanosine. The investigators were interested in modelling the CD4 cell count as a function of treatment, age at base-line and disease stage at base-line. Serious concerns can be raised about the normality assumption of CD4 cell counts that is implicit in many methods and therefore an analysis may have to start with a transformation. Instead of assuming that we know the transformation (e.g. logarithmic) that makes the outcome normal and linearly related to the covariates, we estimate the transformation, by using maximum likelihood, within the Box–Cox family. There has been considerable work on the Box–Cox transformation for univariate regression models. Here, we discuss the Box–Cox transformation for longitudinal regression models when the outcome can be missing over time, and we also implement a maximization method for the likelihood, assumming that the missing data are missing at random. 相似文献
955.
In this investigation we examined partners' responses to unmet intimacy needs in hopes of better understanding how these responses may affect intimacy satisfaction and overall relationship satisfaction. Eighty-four married couples, plus four additional husbands and 12 additional wives, were recruited from the community and completed measures of relationship satisfaction, intimacy need satisfaction, and attributional and communication responses to unmet intimacy needs. Consistent with the proposed mediational model, less negative attributional and communication responses to unmet intimacy needs were found to be beneficial for overall intimacy satisfaction and relationship satisfaction. In addition, more positive communication responses contributed to greater intimacy satisfaction. Limitations and clinical implications of the current study and directions for future work are discussed. 相似文献
956.
The present study evaluated the subjective happiness of Lebanese college youth using a multi-item rather than a single-item subjective happiness measure. An Arabic translation of the Subjective Happiness Scale (SHS) was administered to 273 Lebanese college youth from state- and private-run higher institutions of learning, as was the Arabic Adult Parental Acceptance-Rejection Questionnaire (Arabic PARQ). The reliability and validity of the Arabic SHS was tested in terms of factor analysis, internal consistency, and correlation with Arabic PARQ scores, as was the factorial invariance and relation of the scale across age, sex, marital status, birth order, and college campus. The Arabic SHS showed a reliable unitary structure similar to those found in other cultures, and factorial invariance across sex, marital status, birth order and college campus. While age, sex, marital status and birth order were independent of happiness scores, college students attending the private university reported greater happiness than those from the state-run academic setting. It was concluded that the Lebanese Arabic SHS is a reliable and valid measure of global subjective happiness, its factor structure is similar across other translated versions of the scale, and its scores are independent of age, sex, marital status and birth order. 相似文献
957.
M. H. Akhbari R. Hasni O. Favaron H. Karami S. M. Sheikholeslami 《Journal of Combinatorial Optimization》2013,26(1):10-18
A set S of vertices of a graph G is an outer-connected dominating set if every vertex not in S is adjacent to some vertex in S and the subgraph induced by V?S is connected. The outer-connected domination number $\widetilde{\gamma}_{c}(G)$ is the minimum size of such a set. We prove that if δ(G)≥2 and diam?(G)≤2, then $\widetilde{\gamma}_{c}(G)\le (n+1)/2$ , and we study the behavior of $\widetilde{\gamma}_{c}(G)$ under an edge addition. 相似文献
958.
A set S of vertices of a graph G=(V,E) without isolated vertex is a total dominating set if every vertex of V(G) is adjacent to some vertex in S. The total domination number γ t (G) is the minimum cardinality of a total dominating set of G. The total domination subdivision number $\mathrm{sd}_{\gamma_{t}}(G)$ is the minimum number of edges that must be subdivided (each edge in G can be subdivided at most once) in order to increase the total domination number. Favaron, Karami, Khoeilar and Sheikholeslami (J. Comb. Optim. 20:76–84, 2010a) conjectured that: For any connected graph G of order n≥3, $\mathrm{sd}_{\gamma_{t}}(G)\le \gamma_{t}(G)+1$ . In this paper we use matching to prove this conjecture for graphs with no 3-cycle and 5-cycle. In particular this proves the conjecture for bipartite graphs. 相似文献
959.
Salvatore Greco Benedetto Matarazzo Roman Słowiński 《Zeitschrift für Betriebswirtschaft》2013,83(1):29-60
The paper is about portfolio selection in a non-Markowitz way, involving uncertainty modeling in terms of a series of meaningful quantiles of probabilistic distributions. Considering the quantiles as evaluation criteria of the portfolios leads to a multiobjective optimization problem which needs to be solved using a Multiple Criteria Decision Aiding (MCDA) method. The primary method we propose for solving this problem is an Interactive Multiobjective Optimization (IMO) method based on so-called Dominance-based Rough Set Approach (DRSA). IMO-DRSA is composed of two phases: computation phase, and dialogue phase. In the computation phase, a sample of feasible portfolio solutions is calculated and presented to the Decision Maker (DM). In the dialogue phase, the DM indicates portfolio solutions which are relatively attractive in a given sample; this binary classification of sample portfolios into ‘good’ and ‘others’ is an input preference information to be analyzed using DRSA; DRSA is producing decision rules relating conditions on particular quantiles with the qualification of supporting portfolios as ‘good’; a rule that best fits the current DM’s preferences is chosen to constrain the previous multiobjective optimization in order to compute a new sample in the next computation phase; in this way, the computation phase yields a new sample including better portfolios, and the procedure loops a necessary number of times to end with the most preferred portfolio. We compare IMO-DRSA with two representative MCDA methods based on traditional preference models: value function (UTA method) and outranking relation (ELECTRE IS method). The comparison, which is of methodological nature, is illustrated by a didactic example. 相似文献
960.
Many durable products provide value only when used together with contingent services or consumable components, e.g. light fixtures (bulbs), printers (ink), electronics (batteries). Consumers need only have access to the contingent consumable components to continue to derive service from a durable. In fact, many firms rely primarily upon the revenues generated from the contingent services or consumables as the primary source of profitability, e.g. giving away the razors to make money on the blades. Such firms often invest considerable effort into making sure that consumers of their durables are held captive to their own branded consumables by impeding their access to generically available consumables. They do so by designing their products in such a way that they are not readily compatible with the generic consumables. We consider the implications of competition from third-party manufacturers that can provide generic consumables and the manufacturer’s production decisions of a durable good under such contingencies. This allows us to draw managerial insights about how a firm should decide on his product compatibility and production quantity when the generic contingent consumables enter the market. 相似文献