全文获取类型
收费全文 | 266篇 |
免费 | 0篇 |
专业分类
系统科学 | 3篇 |
理论与方法论 | 1篇 |
现状及发展 | 36篇 |
研究方法 | 32篇 |
综合类 | 174篇 |
自然研究 | 20篇 |
出版年
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 12篇 |
2011年 | 39篇 |
2010年 | 2篇 |
2009年 | 3篇 |
2008年 | 12篇 |
2007年 | 6篇 |
2006年 | 22篇 |
2005年 | 12篇 |
2004年 | 17篇 |
2003年 | 11篇 |
2002年 | 16篇 |
2001年 | 4篇 |
2000年 | 6篇 |
1999年 | 2篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1971年 | 4篇 |
1970年 | 7篇 |
1969年 | 4篇 |
1968年 | 3篇 |
1967年 | 1篇 |
1965年 | 3篇 |
1961年 | 1篇 |
1959年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有266条查询结果,搜索用时 15 毫秒
261.
Howard J. Berna 《西北部美国博物学家》2011,50(2)
Observations of 23 dwarf shrews ( Sorex nanus ) at Fracas Lake in Arizona extend the range of this uncommon shrew northward on the Kaibab Plateau and provide further information regarding the ecology and habitat requirements of this species. Shrews were captured in a previously unreported habitat type (Rocky Mountain montane conifer forest; Brown 1982). This study illustrates the usefulness of intensive, long-term studies and faunal surveys using pitfall traps. 相似文献
262.
Howard E. Evans 《西北部美国博物学家》2011,47(2)
Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Three species of predators and parasites were found associated with western spruce budworm ( Choristoneura occidentalis Freeman) (Lepidoptera, Tortricidae) in Larimer Co., Colorado. These were: Ancistrocerus antilope (Panzer) (Hymenoptera, Vespidae), Goniozus gracilicornis (Kieffer) (Hymenoptera, Bethylidae), and Ceromasia auricaudata Townsend (Diptera, Tachinidae). The first two species stored caterpillars in wooden trap nests, while the third was reared from final instar budworms. 相似文献
263.
Jeffrey Howard Black 《西北部美国博物学家》2011,36(4)
Desert Tortoises ( Gopherus agassizi ) from Utah showed courtship behavior consisting of a complex series of behavioral elements. 相似文献
264.
Moapa dace ( Moapa coriacea ) is a federally listed endangered fish endemic to the spring-fed headwaters of the Muddy River, Clark County, Nevada. Species life history, abundance, and distribution were studied from March 1984 to January 1989. Reproduction, which was observed year-round, peaked in spring and was lowest in fall. It occurred in headwater tributaries of the Muddy River within 150 m of warm water spring discharge in water temperatures ranging from 30 to 32 C. Females matured between 41 and 45 mm in fork length (FL). Egg abundance increased with female size ( r 2 = .93); counts ranged from 60 for a 45-mm-FL female to 772 for one 90-mm FL. The oldest of eight fish, aged by the opercle method, was a 90-mm-FL, 4+-year-old female. Adults are omnivorous but tended toward carnivory; 75% of matter by volume consumed was invertebrates and 25% plants and detritus. Fish size was generally commensurate with flow, the largest fish occurring in the greatest flow. Adults were near bottom, in focal velocities ranging from 0 to 55 cm/s. Juveniles occupied a narrower range of depths and velocities than adults, and larvae occupied slack water. From December 1984 to September 1987, the total adult population ranged from 2600 to 2800. Although these numbers are higher than previously believed for Moapa dace, they are still sufficiently low to warrant its endangered status. The dependency of Moapa dace's different life history stages to various areas and habitat types of the Warm Springs area suggests that all remaining habitat is necessary for their survival. 相似文献
265.
266.