全文获取类型
收费全文 | 308篇 |
免费 | 7篇 |
专业分类
安全科学 | 14篇 |
环保管理 | 35篇 |
综合类 | 128篇 |
基础理论 | 63篇 |
环境理论 | 1篇 |
污染及防治 | 48篇 |
评价与监测 | 10篇 |
社会与环境 | 10篇 |
灾害及防治 | 6篇 |
出版年
2020年 | 4篇 |
2018年 | 7篇 |
2016年 | 9篇 |
2015年 | 5篇 |
2013年 | 11篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 8篇 |
2009年 | 11篇 |
2008年 | 10篇 |
2007年 | 12篇 |
2006年 | 14篇 |
2005年 | 4篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 10篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1989年 | 4篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1974年 | 5篇 |
1971年 | 4篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1967年 | 6篇 |
1966年 | 3篇 |
1965年 | 4篇 |
1964年 | 4篇 |
1961年 | 7篇 |
1960年 | 4篇 |
1958年 | 2篇 |
1957年 | 4篇 |
1956年 | 4篇 |
1955年 | 3篇 |
1948年 | 4篇 |
1940年 | 3篇 |
1938年 | 2篇 |
1937年 | 3篇 |
1928年 | 3篇 |
1927年 | 2篇 |
1920年 | 5篇 |
1916年 | 3篇 |
1913年 | 3篇 |
排序方式: 共有315条查询结果,搜索用时 15 毫秒
211.
Tight junction strands are lipidic cylinders 总被引:1,自引:0,他引:1
H. W. Meyer 《Die Naturwissenschaften》1983,70(5):251-252
212.
D. L. Meyer C. A. LaHaye N. D. Holland A. C. Arneson J. R. Strickler 《Marine Biology》1984,78(2):179-184
Aspects of feather star behavior and ecology were recorded by time-lapse cinematography approximately 1 frame min-1 on the Great Barrier Reef, Australia over a 1 mo period in 1983. The current regime influenced body postures of most species studied, whether nocturnal or not. Moreover, feather stars of several species crawled on the substratum with their arms; each crawling episode lasted roughly 10 min, and the maximum speed attained was about 1 arm length min-1. Nocturnal feather stars crawled to their nighttime feeding perches around dusk and crawled back to their daytime hiding places around dawn. Surprisingly, some species of feather stars living on the reef surface both day and night also crawled around at dawn and dusk for reasons that are not known. In the time-lapse films, and individual of Comanthus bennetti (sex undetermined) spawned for about 2 min just after dark on 5 July 1983. Another film showed possible predation on a feather star (Himerometra robustipinna) by a saddled coralfish (Chaetodon ephippium). 相似文献
213.
214.
Ingeborg Meyer 《Die Naturwissenschaften》1957,44(24):635-636
215.
D. L. Meyer 《Marine Biology》1971,9(3):235-241
A major adaptive problem among comatulid crinoids is the need for a system of articulation and muscularization of the skeleton which provides rigidity in the cirri, arms, and pinnules for maintaining position and feeding in moving water masses, and also the ability to undergo occasional rapid flexions. Most skeletal ossicles of comatulids are united by so-called ligament fibers, while arm articulations possess masses of muscle as well as ligament. Light and electron microscopic work shows that the ligament consists primarily of collagen fibers. Similarity of this dual system of crinoid arm musculature to the muscles and collagenous catch apparatus of echinoid spines suggests that the crinoid ligaments may provide the needed rigidity to the crinoid skeleton, in a manner similar to that by which the echinoid catch apparatus can hold the spine tightly to the test in one position. 相似文献
216.
217.
The Science of Nature - 相似文献
218.
Cassel T Ashbaugh L Flocchini R Meyer D 《Journal of the Air & Waste Management Association (1995)》2005,55(6):816-825
Ammonia emissions contribute to the formation of secondary particulate matter (PM) and violations of the National Ambient Air Quality Standard. Ammonia mass concentration measurements were made in February 1999 upwind and downwind of an open-lot dairy in California, using a combination of active bubbler and passive filter samplers. Ammonia fluxes were calculated from concentrations measured at 2, 4, and 10 m above ground at three locations on the downwind edge of the dairy, using micrometeorological techniques. A new method was developed to interpolate fluxes at six additional locations from ammonia concentrations measured at a single height, providing measurements at sufficient spatial resolution along the downwind border of the dairy to account for the heterogeneity of the source. PM measured up- and downwind of the dairy demonstrated insignificant ammonium particle formation in the immediate vicinity of the dairy and negligible contribution of dissociated ammonium nitrate to measured ammonia concentrations. Ammonium nitrate concentrations measured downwind of the dairy ranged from 26 to 0.26 microg m(-3) and from 2 to 43% of total PM2.5 mass concentrations. Measured ammonia fluxes showed that liquid manure retention ponds represented relatively minor sources of ammonia in winter on the dairy studied. Ammonia emission factors derived from the measurements ranged from 19 to 143 g head(-1) day(-1), showing an increase with warmer, drier weather and a decrease with increased relative humidity and lower temperatures. 相似文献
219.
Judy L. Meyer David L. Strayer J. Bruce Wallace Sue L. Eggert Gene S. Helfman Norman E. Leonard 《Journal of the American Water Resources Association》2007,43(1):86-103
Abstract: The diversity of life in headwater streams (intermittent, first and second order) contributes to the biodiversity of a river system and its riparian network. Small streams differ widely in physical, chemical, and biotic attributes, thus providing habitats for a range of unique species. Headwater species include permanent residents as well as migrants that travel to headwaters at particular seasons or life stages. Movement by migrants links headwaters with downstream and terrestrial ecosystems, as do exports such as emerging and drifting insects. We review the diversity of taxa dependent on headwaters. Exemplifying this diversity are three unmapped headwaters that support over 290 taxa. Even intermittent streams may support rich and distinctive biological communities, in part because of the predictability of dry periods. The influence of headwaters on downstream systems emerges from their attributes that meet unique habitat requirements of residents and migrants by: offering a refuge from temperature and flow extremes, competitors, predators, and introduced species; serving as a source of colonists; providing spawning sites and rearing areas; being a rich source of food; and creating migration corridors throughout the landscape. Degradation and loss of headwaters and their connectivity to ecosystems downstream threaten the biological integrity of entire river networks. 相似文献
220.