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281.
The spread of the international AIDS pandemic has drawn attention to the urgent need for data on human sexual behavior; yet the lack of an established tradition of theory and method in sex research has limited the development of research initiatives in this area. This has been particularly true in the study of homosexual and bisexual behavior, which has relied heavily on the use of quantitative survey methods that largely fail to address cross‐cultural differences in the structure and meaning of same‐sex sexual experience. More qualitative approaches offer the possibility of investigating homosexual and bisexual behavior within a broader social and cultural context and can therefore play an important role in developing a framework for the comparative analysis of behavioral data. This article seeks to contribute to the development of theory and method in sex research by outlining key research issues and possible methodologies for the qualitative investigation of homosexual and bisexual behavior in relation to HIV/AIDS.  相似文献   
282.
Nowadays, the majority of human beings live in urban ecosystems, with this proportion expected to continue increasing in the future. With the growing importance of urban rat-associated issues (e.g. damages to urban infrastructures, costs of rat-control programs, rat-associated health risks), it is becoming indispensable to fill the identified gaps in knowledge on the urban brown rat regarding, among others, its density, home range, genetic structure, and infectious status. In this context, live-trapping is a crucial prerequisite to any scientific investigation. This paper assesses the main constraints and challenges regarding the urban field and describes the major steps to be considered when planning research on urban rats. The primary challenges are i) the characterization of the urban experimental unit; ii) the choice of a trapping design: the use of live-trapping in capture-mark-recapture design, in association with modern statistics, is highly recommended to answer ecological questions (although these methods, mostly developed in natural ecosystems, need to be implemented for the urban field); iii) the potential ethical considerations with regard to animal welfare and field-worker safety; iv) the building of mutually-beneficial collaborations with city stakeholders, pest control professionals, and citizens. Emphasis must be put on communication to the public and education of field-workers. One major need of modern urban rat research is a peer-validated field methodology allowing reproducibility, repeatability, and inference from urban field studies and enabling researchers to answer long-standing key questions about urban rat ecology.  相似文献   
283.
284.
Much research to date has tended to view vulnerability by discipline or sector, despite the fact that individuals and households experience multiple, interacting and sometimes compound vulnerabilities. However, cross-disciplinary thinking on vulnerability has emerged. At the same time, also emergent is an alternative to traditional thinking on poverty, which shifts the focus away from poverty as a static set of deprivations towards poverty as a dynamic set of interacting material, relational and subjective aspects of life in a human wellbeing perspective. The contribution of this paper is to bring together these two strands of thinking in order to explore the ways in which a human wellbeing conceptual framework might contribute to the analysis of vulnerability in terms of better capturing the multidimensionality of vulnerability.  相似文献   
285.

A survey is given of the use of modern statistical techniques in event history analysis, and in particular in the study of multi‐state life‐tables in demography. Emphasis is placed on the interplay between partial likelihood and nonparametric maximum likelihood based methods, a) when analysing semi‐Markov models or models with repeated spells, and b) in frailty models for inobservable heterogeneity.  相似文献   
286.
A tank car derailment in northern California in 1991 spilled metam sodium into the Sacramento River, and released its breakdown product, methyl isothiocyanate (MITC), into the air. This paper describes the risk evaluation process used. Over 240 individuals reported symptoms such as eye and throat irritation, dizziness, and shortness of breath. Reference exposure levels (RELs) for 1 hr were developed for MITC and compared to exposure concentrations. Ocular irritation in cats was the most sensitive endpoint reported. The no observed adverse effect level (NOAEL), divided by an uncertainty factor (UF) of 100, produced an REL of 0.5 ppb of MITC in air to prevent discomfort. An REL to prevent disability was estimated to be 40 ppb. An REL to prevent life-threatening injury was estimated to be 150 ppb. Measured MITC levels ranged from 0.2-37 ppb and estimated peak levels ranged from 140-1600 ppb. The usefulness of RELs for emergency planning is discussed.  相似文献   
287.
This article describes how a risk-return portfolio analysis, as originally developed in economics and finance, can be applied to product-line decisions. This approach uses direct estimates of return, and explicitly considers risk, or variation in return; most of the product portfolio models in use today forecast return by correlation, and lack explicit treatment of risk. The approach provides guidance for new product development activities as well as for allocating resources among a corporation's existing product lines. The article explains how organizations can apply this approach to their own product portfolio decisions, and includes a detailed example of how one company used this model.  相似文献   
288.
Traditional risk assessments, including those involving the United States Department of Energy (USDOE), are often criticized for producing useless or noncredible management responses because they did not meaningfully involve the public. The first step to involve the public is to identify appropriate active participants (stakeholders). This study was done to understand the processes used to identify stakeholders to serve on advisory boards established at the two largest remediation sites in the United States: the Hanford Nuclear Reservation in Washington state and the Savannah River Site in South Carolina. The Hanford stakeholder identification process produced an interest-based board whereas the Savannah River Site strategy produced population-based representation. The basic goals of the stakeholder advisory groups were similar. However, different processes were used to identify the participants for the groups in part because of distinctly different social and cultural conditions in the areas affected by the operations of the two facilities, and in part because of the different level of trust of the USDOE and their contractors at Hanford compared with Savannah River. The discussion analyzes their different needs and potential for successful citizen participation.  相似文献   
289.
Morton L. Mandel, CEO of Cleveland-based Premier Industrial Corporation, with brothers Jack and Joe, started selling automotive fasteners out of garage 50 years ago. Today, Premier's sales are running at a record $650m clip. The market value of the Mandel brothers' publicly-traded Premier shares earns all three a place on Forbes' list of the 400 wealthiest Americans. The family still holds about 60 per cent of the stock. Mort Mandel believes that gives the company independence and the ability to concentrate on nuts and bolts rather than politics. Mandel's nuts and bolts approach to managing has created stunning success—after-tax margins twice the average of Premier's industry, return on assets of 24 per cent, return on investment above 30 per cent, earnings per share compounded in excess of 17 per cent for the past 5 years, shareholders' equity that has grown close to 10 per cent annually for 20 years, and debt of less than 3 per cent of net worth. Mandel says it's simple: Treat customers as though they have the ‘right’ to superior service. Behave ethically, professionally and personally. Do good. Invest in people. Execute, execute, execute. What he calls Management 101. We suspected it wasn't quite that simple, and we wanted to know how he created a company that repeatedly outperforms its industry and many others, how he sustains a culture that generates 5000 written profit improvement ideas a year from Premier's 5400 employees. So we asked him some questions about his views on management and leadership that produced refreshing insights into the power, purity and timeless applicability of ‘management basics’. This interview was conducted at Premier's unpretentious executive offices, located in the Midtown Corridor of Cleveland, Ohio, a privately-sponsored urban renewal project inspired by Mort Mandel, who practices his preachings about ‘doing good’.  相似文献   
290.
The purpose of this paper is to examine a type of resource allocation problem arising in the context of research and development activities. The particular problem analyzed involves scheduling a group of projects in such a way that total cost is minimized while several precedence relations are satisfied and specific completion times are maintained. The primary difficulty results from the existence of commonalities that allow the successful completion of a particular project to be applied to several different purposes. A solution approach is developed which combines a one-pass network algorithm to deal with the precedence and time restrictions and a dynamic programming procedure to allocate the resources to each project.  相似文献   
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