全文获取类型
收费全文 | 91935篇 |
免费 | 1239篇 |
国内免费 | 1211篇 |
专业分类
安全科学 | 3770篇 |
废物处理 | 3410篇 |
环保管理 | 14062篇 |
综合类 | 21214篇 |
基础理论 | 26387篇 |
环境理论 | 72篇 |
污染及防治 | 15613篇 |
评价与监测 | 5570篇 |
社会与环境 | 3729篇 |
灾害及防治 | 558篇 |
出版年
2022年 | 841篇 |
2021年 | 843篇 |
2020年 | 665篇 |
2019年 | 878篇 |
2018年 | 1165篇 |
2017年 | 1188篇 |
2016年 | 2206篇 |
2015年 | 1844篇 |
2014年 | 2604篇 |
2013年 | 9268篇 |
2012年 | 2267篇 |
2011年 | 2554篇 |
2010年 | 3278篇 |
2009年 | 3428篇 |
2008年 | 2131篇 |
2007年 | 2002篇 |
2006年 | 2373篇 |
2005年 | 2331篇 |
2004年 | 2662篇 |
2003年 | 2513篇 |
2002年 | 2038篇 |
2001年 | 2435篇 |
2000年 | 2090篇 |
1999年 | 1528篇 |
1998年 | 1372篇 |
1997年 | 1363篇 |
1996年 | 1486篇 |
1995年 | 1580篇 |
1994年 | 1467篇 |
1993年 | 1334篇 |
1992年 | 1309篇 |
1991年 | 1292篇 |
1990年 | 1234篇 |
1989年 | 1206篇 |
1988年 | 1047篇 |
1987年 | 986篇 |
1986年 | 989篇 |
1985年 | 1062篇 |
1984年 | 1161篇 |
1983年 | 1170篇 |
1982年 | 1171篇 |
1981年 | 1100篇 |
1980年 | 943篇 |
1979年 | 937篇 |
1978年 | 821篇 |
1977年 | 722篇 |
1976年 | 645篇 |
1975年 | 605篇 |
1973年 | 639篇 |
1972年 | 643篇 |
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
51.
52.
Tanay B. Yıldırım Tutku Ak Zuhal Ölmez 《Environment, Development and Sustainability》2008,10(6):871-881
While the world is going into different tourism expectations, the tourism understanding in Turkey is defined as tourism in the sea-sand-sun triangle. However, it is possible to contribute to the income and local development of the indigenous people by developing nature-based tourism. Besides, with the sustainable use and preservation of the natural-cultural assets, the damage of the traditional tourism industry on the natural and cultural environment could be reduced. In this study, it is aimed to bring up the nature-based tourism concept in Çanakkale by evaluating the nature-based tourism industry in the general of Turkey and assessing the natural-cultural resources that Çanakkale comprehends. The most important areas that have a nature-based tourism potential in Çanakkale and the tourism activities that are most suitable for these areas have been determined. 相似文献
53.
Molecular phylogeny and population structure of tideland snails in the genus Cerithidea around Japan
Phylogenetic relationships and genetic population structures were analyzed for tideland gastropods in the genus Cerithidea around Japan on the basis of partial sequence of the mitochondrial COI gene. Large genetic divergence was shown between individuals of Cerithidea cingulata in the southern Ryukyus and those in the central Ryukyus and the Japanese Islands. Haplotypes of C. cingulata from the Japanese Islands were paraphyletic with the exclusion of a monophyletic group from the central Ryukyus. Genetic differentiation of C. cingulata was also detected between Amami-Oshima Island and Okinawajima Island. No genetic divergence was found between Cerithidea rhizophorarum in the Japanese Islands and its subspecies C. rhizophorarum morchii in the Ryukyu Islands. The lack of genetic divergence of Cerithidea largillierti between continental China and Japan suggests relatively recent migration between the Japanese Islands and the Asian continent. For all three Cerithidea species distributed in both the Japanese Islands and the Ryukyu Islands, the Tokara Gap and the Kerama Gap were shown to have acted as barriers to the dispersal. 相似文献
54.
55.
56.
57.
58.
59.
Greg R. J. Sutherland Joachim Haselbach Steven D. Aust 《Environmental science and pollution research international》1997,4(1):16-20
Two synthetic superabsorbent crosslinked acrylic polymers were mineralized by the white-rot fungusPhanerochaete chrysosporium. The amount of polymer converted to CO2 increased as the amount of polymer added to the cultures increased. In the presence of sufficiently large amounts of the superabsorbents, such that all of the culture fluid was absorbed and a gelatinous matrix was formed, the fungus still grew and mineralization was observed. Neither the polymers, nor their degradation products were toxic to the fungus. While the rates of mineralization were low, all of the polymers incubated in the liquid fungal cultures were completely depolymerized to water soluble products within 15–18 days. The depolymerization of the polymers was observed only in nitrogen limited cultures of the fungus which secrete the lignin degradation system, however, the water soluble products of depolymerization were mineralized in both nutrient limited and sufficient cultures of the fungus. The rate of mineralization of the depolymerized metabolites was more than two times greater in nutrient sufficient cultures. Following longer incubation periods, most (> 80 %) of the radioactivity was recovered in the fungal mycelial mat suggesting that carbon of the polymer had been converted to fungal metabolites. 相似文献
60.
We examined the impact of seven species of mobile mushroom corals (Fungiidae) on the community structure of sheltered reef slopes in terms of their patterns of migration, habitat use and competition with other benthic organisms. On fringing reefs at Eilat, Red Sea, polyps detached at 1 to 6 cm length, and grew to 11–55 cm length. Attached mushroom corals were oriented vertically in reef cavities. Detached corals migrated downward on the reef slope and onto rubble or soft substratum at the reef base, at 29 to 71 cmyr–1. Mobility decreased with corallum size and extent of undersurface ornamentation. In aquaria, small corals righted themselves and migrated up to 6 cm d–1 by nocturnally inflating and pushing their tissues against the substratum. Autonomous coral behavior and storm-generated water motion appeared to account for most fungiid mobility at Eilat. Mushroom corals did not damage each other upon contact, even in multi-species aggregations, but unilaterally damaged non-fungiid scleractinian corals. Their dominance during contact interactions retards overgrowth by larger attached scleractinians, and mobility allows them to colonize soft substrata not accessible to most other reef corals. 相似文献