全文获取类型
收费全文 | 20565篇 |
免费 | 211篇 |
国内免费 | 311篇 |
专业分类
安全科学 | 583篇 |
废物处理 | 901篇 |
环保管理 | 2719篇 |
综合类 | 2921篇 |
基础理论 | 5437篇 |
环境理论 | 6篇 |
污染及防治 | 6050篇 |
评价与监测 | 1355篇 |
社会与环境 | 980篇 |
灾害及防治 | 135篇 |
出版年
2022年 | 182篇 |
2021年 | 189篇 |
2020年 | 121篇 |
2019年 | 176篇 |
2018年 | 344篇 |
2017年 | 287篇 |
2016年 | 464篇 |
2015年 | 405篇 |
2014年 | 579篇 |
2013年 | 1758篇 |
2012年 | 669篇 |
2011年 | 886篇 |
2010年 | 709篇 |
2009年 | 816篇 |
2008年 | 947篇 |
2007年 | 1010篇 |
2006年 | 860篇 |
2005年 | 719篇 |
2004年 | 755篇 |
2003年 | 720篇 |
2002年 | 685篇 |
2001年 | 929篇 |
2000年 | 653篇 |
1999年 | 359篇 |
1998年 | 266篇 |
1997年 | 258篇 |
1996年 | 290篇 |
1995年 | 299篇 |
1994年 | 289篇 |
1993年 | 266篇 |
1992年 | 230篇 |
1991年 | 210篇 |
1990年 | 228篇 |
1989年 | 218篇 |
1988年 | 200篇 |
1987年 | 183篇 |
1986年 | 164篇 |
1985年 | 160篇 |
1984年 | 192篇 |
1983年 | 195篇 |
1982年 | 186篇 |
1981年 | 181篇 |
1980年 | 145篇 |
1979年 | 171篇 |
1978年 | 117篇 |
1977年 | 107篇 |
1976年 | 92篇 |
1975年 | 106篇 |
1973年 | 100篇 |
1972年 | 109篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Rate-temperature responses in scyphozoan medusae and polyps 总被引:1,自引:0,他引:1
The effects of temperature on oxygen consumption and spontaneous rhythmic activity have been investigated in various stages of the life histories of 3 species of jellyfish from the Chesapeake Bay, USA. All 3 species clearly show the ability to acclimate positively to temperature change. Thermal sensitivity of metabolism in the winter medusa Cyanea capillata fulva is fairly low at temperature intervals which are experienced in nature. Polyps of the two summer medusae, Chrysaora quinquecirrha and Aurelia aurita, show reduced metabolic sensitivity at temperatures normally accompanying high developmental activity and the onset of strobilation. 相似文献
82.
83.
84.
85.
86.
87.
88.
Interactions between the red algaPlocamium hamatum J. Agardh (Rhodophyta) and other benthic organisms including the alcyonacean soft coralSinularia cruciata (Tixier-Durivault) were investigated on an inshore fringing reef environment in whichP. hamatum was the dominant large fleshy alga. Field observations of sessile reef organisms including octocorals and sponges living in close proximity toP. hamatum revealed that varying degrees of tissue necrosis were suffered by the invertebrates when in physical contact with the alga. In order to establish whether the chemical constituents of the alga, especially chloromertensene, played a role in this necrosis, manipulative field experiments were carried out in the Pelorus Channel, Palm Island group (18°34S; 146°29E), North Queensland, Australia, in November and December 1988. The first experiment involved the relocation of healthy plants and soft corals into contact and non-contact situations on a mesh grid. In all cases of contact betweenP. hamatum andS. cruciata, the soft coral suffered tissue necrosis (n=6,p=0.0022). The second experiment had the same design, but involved the use of artificial plants both uncoated and coated with natural levels of chloromertensene, in contact withS. cruciata. In all cases of contact with coated treatments, necrosis was observed inS. cruciata (n=4,p=0.025). In cases where uncoated artificial fronds were placed in contact with soft corals,S. cruciata showed minor abrasion effects, but no appreciable necrosis. Coated treatments were not fouled by epiphytes during the experiment and were not consumed by predators. Uncoated treatments were rapidly reduced in size by predation and any remaining material was biofouled. These experiments thus demonstrated that the deleterious effects observed in soft corals in the field were caused by contact with the algaP. hamatum, that these effects were indeed chemically mediated by chloromertensene, and that physical contact without chemical intervention caused no such deleterious effects. This is the first experimental evidence which conclusively demonstrates allelopathy between an alga and other marine organisms and identifies the compound responsible for the observed allelopathic effects. 相似文献
89.
Monitoring of airborne dust in Delhi during May to July 1985 revealed residues of DDT varying from 1.3 to 7.14 ng mg(-1) (4.06-22.31 ng m(-2) day(-1)) with an average of 3.32 ng mg(-1) (10.38 ng m(-2) day(-1)), and HCH which ranged from 0.46 to 2.35 ng mg(-1) (1.44-7.34 ng m(-2) day(-1)) with a mean of 1.16 ng mg(-1) (3.63 ng m(-2) day(-1)). The concentration of total DDT was almost 3 times greater than that of HCH. 相似文献
90.
Hiraoka Y 《Environmental pollution (Barking, Essex : 1987)》1991,70(3):209-217
Cultured oysters from Hiroshima Bay were analysed to determine the content of nine trace elements, cadmium (Cd), lead (Pb), chromium (Cr), arsenic (As), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), and iron (Fe) and compared with oysters treated for 48 h in both artificial sea water and a solution of 0.5% ethylenediaminetetraacetic acid (EDTA) in artificial sea water. It was found that the values of As and Fe in both groups of treated oysters were significantly lower than in the untreated oysters and that the Pb and Mn levels tended to be lower. It was also found that oysters treated in 0.5% EDTA solution in artificial sea water had lower levels of Cd and Cu than the oysters treated only in artificial sea water. 相似文献