全文获取类型
收费全文 | 2623篇 |
免费 | 131篇 |
出版年
2023年 | 17篇 |
2020年 | 40篇 |
2019年 | 77篇 |
2018年 | 88篇 |
2017年 | 125篇 |
2016年 | 114篇 |
2015年 | 72篇 |
2014年 | 61篇 |
2013年 | 862篇 |
2012年 | 64篇 |
2011年 | 80篇 |
2010年 | 75篇 |
2009年 | 70篇 |
2008年 | 68篇 |
2007年 | 53篇 |
2006年 | 41篇 |
2005年 | 29篇 |
2004年 | 48篇 |
2003年 | 42篇 |
2002年 | 53篇 |
2001年 | 36篇 |
2000年 | 28篇 |
1999年 | 29篇 |
1998年 | 27篇 |
1997年 | 26篇 |
1996年 | 13篇 |
1995年 | 14篇 |
1994年 | 14篇 |
1993年 | 32篇 |
1992年 | 15篇 |
1991年 | 20篇 |
1990年 | 22篇 |
1989年 | 17篇 |
1988年 | 23篇 |
1987年 | 23篇 |
1986年 | 15篇 |
1985年 | 23篇 |
1984年 | 22篇 |
1983年 | 19篇 |
1982年 | 20篇 |
1981年 | 19篇 |
1980年 | 28篇 |
1979年 | 17篇 |
1978年 | 21篇 |
1977年 | 27篇 |
1976年 | 29篇 |
1975年 | 16篇 |
1973年 | 12篇 |
1971年 | 10篇 |
1970年 | 9篇 |
排序方式: 共有2754条查询结果,搜索用时 15 毫秒
991.
Inglehart's thesis of value change is one of the most widely discussed accounts of social and political change in advanced Western nations. This article offers a critique of Inglehart's thesis and a clarification of the Australian case. While critics of Inglehart have attacked the validity of his values measures, or sought to improve them, we use Inglehart's own values index to show that even if--as Inglehart claims--his measures are valid, the age/values predictions do not hold as the theory suggests in Australia. In a recent article, Inglehart and Abramson (1999, 673) cite Australia among a group of '28 high-income' countries that exhibit 'stronger relationships between values and age' than found in the United States. We dispute Inglehart and Abramson's findings in relation to Australia. We show that the relationship between age and values in Australia, like the United States, is very weak, highlight the problematic nature of assuming a linear relationship between age and values without evidence, and discover a new non-linear relationship between values and birth cohorts in Australia that has implications for the study of values research internationally. 相似文献
992.
P. Upton D. Craw T. G. Caldwell P. O. Koons Z. James P. E. Wannamaker G. J. Jiracek C. P. Chamberlain 《Geofluids》2003,3(1):1-12
The currently active fluid regime within the outboard region of the Southern Alps, New Zealand was investigated using a combination of field observations, carbon‐ and oxygen‐stable isotopes from fault‐hosted calcites and interpretation of magnetotelluric (MT) data. Active faulting in the region is dominated by NE striking and N striking, oppositely dipping thrust fault pairs. Stable isotopic analyses of calcites hosted within these fault zones range from 10 to 25‰δ18O and from ?33 to 0‰δ13C. These values reflect mixing of three parent fluids: meteoric water, carbon‐exchanged groundwater and minor deeper rock‐exchanged fluids, at temperatures of 10–90°C in the upper 3–4 km of the crust. A broad, ‘U‐shaped’ zone of high electrical conductivity (maximum depth c. 28 km) underlies the central Southern Alps. In the ductile region of the crust, the high‐conductivity zone is subhorizontal. Near‐vertical zones of high conductivity extend upward to the surface on both sides of the conductive zone. On the outboard side of the orogen, the conductive zone reaches the surface coincident with the trace of the active Forest Creek Faults. Near‐surface flow is shown to dominate the outboard region. Topographically driven meteoric water interacts, on a kilometre scale, with either carbon‐exchanged groundwater or directly with organic material within Pliocene gravels, resulting in a distinctive low 13C signal within fault‐hosted calcites of the outboard region. The high‐strain zone in the lower crust focuses the migration of deeply sourced fluids upward to the base of the brittle–ductile transition. Interconnected fluid is imaged as a narrow vertical zone of high conductivity in the upper crust, implying continuous permeability and possibly buoyancy‐driven flow of deeply sourced fluids to higher levels of the crust where they are detected by the isotopic analysis of the fault‐hosted calcites. 相似文献
993.
994.
995.
Mark Bauerlein 《Journal of the Historical Society》2002,2(3-4):361-362
Book reviewed in this article:
Victor Davis Hanson, John Heath, Bruce S. Thornton, Bonfire of the Humanities: Rescuing the Classics in an Impoverished Age 相似文献
Victor Davis Hanson, John Heath, Bruce S. Thornton, Bonfire of the Humanities: Rescuing the Classics in an Impoverished Age 相似文献
996.
Non-destructive chemical characterization of ceramic sherds from Shipwreck 31CR314 and Brunswick Town, North Carolina 总被引:1,自引:0,他引:1
Lisa S. Schleicher J. William Miller Sarah C. Watkins-Kenney Linda F. Carnes-McNaughton Mark U. Wilde-Ramsing 《Journal of archaeological science》2008,35(10):2824-2838
The purpose of this study was to chemically and texturally characterize ceramic oil jar sherds from North Carolina Shipwreck 31CR314 and to explore the utility of environmental scanning electron microscopy/X-ray energy dispersive spectrometry (SEM/EDS) for that purpose. The oil jar sherds, widely dispersed about Shipwreck 31CR314, are morphologically similar to each other, which suggests they could be from a single jar, but with so few joins this could not be concluded with certainty. Therefore, an aim of this study was to investigate whether chemical or textural characterization of the sherds might reveal unique attributes that could distinguish individual jars; results of characterization perhaps could give information on their origin and possibly site formation processes, such as whether environmental forces could have scattered sherds of a single jar during and after sinking of the ship. Previous studies have indicated this shipwreck is likely the remnants of the Queen Anne's Revenge, flagship of the pirate Blackbeard. Sherds from this shipwreck were compared with similar oil jar sherds excavated from a land site, Brunswick Town, North Carolina, to explore the use of composition and texture as hallmarks. The chemical components of the artifacts were determined by SEM/EDS. This method of analysis is valuable for archaeological research because it is rapid and non-destructive to the ceramic artifacts. Both groups of lead-glazed coarse red earthenware sherds were texturally similar except for the glazed sides of all 31CR314 sherds that exhibited small tracks of unique crescent-shaped marks. These marks may be due to manufacturing effects and immersion in seawater, and the marks may serve as hallmarks for individual jars or potentially individual manufacturers. The sherds were generally similar in composition, but the two groups exhibited distinct differences. Brunswick Town sherds consistently contained more phosphate on unglazed sides, an average 1.46 wt.% P2O5, and also contained trace elements not detected in the Shipwreck 31CR314 sherds. These distinct differences could be due to different manufacturing origins for Shipwreck 31CR314 and Brunswick Town ceramics but also could reflect their subjection to different environments during use and loss prior to archaeological recovery. 相似文献
997.
998.
999.
1000.