全文获取类型
收费全文 | 613篇 |
免费 | 27篇 |
出版年
2023年 | 3篇 |
2020年 | 6篇 |
2019年 | 13篇 |
2018年 | 12篇 |
2017年 | 18篇 |
2016年 | 24篇 |
2015年 | 10篇 |
2014年 | 15篇 |
2013年 | 187篇 |
2012年 | 14篇 |
2011年 | 13篇 |
2010年 | 16篇 |
2009年 | 9篇 |
2008年 | 10篇 |
2007年 | 10篇 |
2006年 | 11篇 |
2005年 | 10篇 |
2004年 | 14篇 |
2003年 | 13篇 |
2002年 | 9篇 |
2001年 | 15篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 10篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 5篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 11篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1969年 | 4篇 |
排序方式: 共有640条查询结果,搜索用时 15 毫秒
11.
12.
13.
The advent of new techniques of dental ageing has permitted inferences about the age-structures of ancient animal populations on the basis of faunal remains. Unfortunately, inference from archaeological populations of faunal elements to the age-structure of ancient herds is fraught with both sampling problems and logical difficulties. The relationship between a living herd—a dynamic system characterized by growth—and a static archaeological population is more complex than that assumed by current models based on kill-off patterns and survivorship curves. Using a computer simulation, these logical relationships are explored, and the effects of herd growth on the composition of live and death populations are evaluated. By employing the simulation within a deductive framework, constrained by ethnographically derived criteria for reproduction, mortality, and economic viability in the Near East, it is possible to determine whether certain archaeological kill-off patterns could represent viable herding systems. Examples were found to vary widely in terms of both demographic plausibility and economic viability. Some implications for the possible course of ova-caprine domestication in the Near East are discussed. 相似文献
14.
Roger M. A. Allen 《Muslim world (Hartford, Conn.)》1972,62(2):115-125
15.
16.
17.
Road safety research is a data-rich field with large social impacts. Like in medical research, the ambition is to build knowledge around risk factors that can save lives. Unlike medical research, road safety research generates empirical findings from messy observational datasets. Records of road crashes contain numerous intersecting categorical variables, dominating patterns that are complicated by confounding and, when conditioning on data to make inferences net of this, observed effects that are subject to uncertainty due to diminishing sample sizes. We demonstrate how visual data analysis approaches can inject rigor into exploratory analysis of such datasets. A framework is presented whereby graphics are used to expose, model and evaluate spatial patterns in observational data, as well as protect against false discovery. Evidence for the framework is presented through an applied data analysis of national crash patterns recorded in STATS19, the main source of road crash information in Great Britain. Our framework moves beyond typical depictions of exploratory data analysis and transfers to complex data analysis decision spaces characteristic of modern geographical analysis. 相似文献
18.
An increasingly salient policy innovation pursued by LGBT+ rights groups and socially liberal policy entrepreneurs is the right of trans people to bring their legally recorded sex in line with their lived gender by way of self-identification. In response to these moves toward trans inclusion, a unique coalition of trans-exclusionary (gender critical) feminists and traditionalist conservatives has emerged to challenge these reforms. This coalition of policy opponents, mirroring historical issue frames that present homosexuals as predatory sexual deviants, campaign on a salient issue frame that presents transgender individuals and the expansion of trans rights as an inimical threat to the security, safety, and welfare of (cisgender) women, particularly in single-sex spaces. In this paper, we address two questions. First, we ask: do trans-exclusionary “protect women” issue frames over the alleged threat of trans persons to (cis) women shape mass public opinion? Second, we ask: in a relatively LGBT+ friendly policy environment, who supports the right to self-identification for trans individuals? We answer these questions via an original pre-registered survey experiment embedded within the 2021 Scottish Election Study. We find that trans-exclusionary issue frames appealing to (cis) women's safety significantly depress support for trans rights, particularly among women respondents. Highlighting these concerns is an effective means of increasing already robust opposition to reforms designed to improve the welfare of transgender individuals, which should be of concern for proponents of self-identification policies. 相似文献
19.
T he technological prowess of the U nited S tates was symbolized by what became known as the space shuttle, which the National Aeronautics and Space Administration (NASA) began to work on in the late 1960s. With the shuttle program NASA planned to facilitate its aggressive space-exploration effort by providing low-cost, reusable transportation to and from Earth's orbit. NASA officials compared the space program's traditional use of expendable launch vehicles to throwing away a railroad locomotive after every train trip, whereas a reusable shuttle would offer cost-effective, routine access to space. Approval of the shuttle initiative required complex political maneuvering by NASA and its supporters between 1969 and 1972. The twists and turns in the approval process actually shaped the final direction that the shuttle program took, demonstrating the pitfalls of decision making by compromise and the challenges of managing large-scale technology programs within the federal government.1 相似文献
20.