全文获取类型
收费全文 | 383篇 |
免费 | 19篇 |
国内免费 | 46篇 |
专业分类
安全科学 | 38篇 |
环保管理 | 34篇 |
综合类 | 225篇 |
基础理论 | 102篇 |
环境理论 | 1篇 |
污染及防治 | 17篇 |
评价与监测 | 10篇 |
社会与环境 | 9篇 |
灾害及防治 | 12篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 17篇 |
2012年 | 9篇 |
2011年 | 32篇 |
2010年 | 12篇 |
2009年 | 14篇 |
2008年 | 16篇 |
2007年 | 17篇 |
2006年 | 28篇 |
2005年 | 20篇 |
2004年 | 23篇 |
2003年 | 18篇 |
2002年 | 16篇 |
2001年 | 13篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 14篇 |
1994年 | 15篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1991年 | 17篇 |
1990年 | 3篇 |
1989年 | 14篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 4篇 |
排序方式: 共有448条查询结果,搜索用时 656 毫秒
391.
The condition of coral reefs in South Florida (2000) using coral disease and bleaching as indicators 总被引:2,自引:0,他引:2
Santavy DL Summers JK Engle VD Harwell LC 《Environmental monitoring and assessment》2005,100(1-3):129-152
The destruction of coral reef habitats has occurred at unprecedented levels during the last three decades. Coral disease and bleaching in the Caribbean and South Florida have caused extensive coral mortality with limited recovery, often coral reefs are being replaced with turf algae. Acroporids were once dominant corals and have diminished to the state where they are being considered as endangered species. Our survey assessed the condition of reef corals throughout South Florida. A probability-based design produced unbiased estimates of the spatial extent of ecological condition, measured as the absence or presence and frequency or prevalence of coral diseases and bleaching intensity over large geographic regions. This approach allowed us to calculate a quantifiable level of uncertainty. Coral condition was estimated for 4100 hectares (ha) (or 41.0 km2) of coral reefs in South Florida, including reefs in the Florida Keys National Marine Sanctuary (FKNMS), New Grounds, Dry Tortugas National Park (DTNP), and Biscayne National Park (BNP). The absence or presence of coral disease, causal coral bleaching, partial bleaching and coral paling were not good indicators of overall coral condition. It was more useful to report the prevalence of anomalies that indicated a compromised condition at both the population and community levels. For example, 79% of the area in South Florida had less than 6% of the coral colonies diseased, whereas only 2.2% (97.15 ha) of the sampled area had a maximum prevalence of 13% diseased coral colonies at any single location. The usefulness of causal bleaching might be more important when considering the prevalence of each of the three different states at a single location. For example, paling was observed over the entire area, whereas bleaching and partial bleaching occurred at 19 and 41% of the area, respectively. An index for coral reef condition might integrate the prevalence and species affected by each bleaching state at individual locations. By establishing these baselines, future surveys can examine changes and trends in the spatial distribution of coral conditions in South Florida and able to score the reefs as to their health status. 相似文献
392.
An investigation on the organic degradation products and selenium in the pathogenesis of Kaschin-Beck disease was carried out. The results demonstrated that the organic degradation products existed in food and drinking water were the pathogens of the KBD; their leading pathological process of cells would be "membrane injury" due to peroxide. As GSH-Px is a selenium contained enzyme, therefore insufficient selenium would be one of the most important conditions to cause KBD. 相似文献
393.
The effect of exposure to crude oil contaminated diet on the blood antioxidant defence system, lipid peroxidation, lipid profile
as well as possible protective roles of vitamins E and C were studied in rabbits. Oxidative stress induction by crude oil
was indicated by significantly (P < 0.05) increased lipid peroxidation and a non-significant (P < 0.05) decrease in superoxide dismutase and catalase activities. A similar pattern was also detected in the lipid profile:
total cholesterol and LDL-cholesterol insignificantly (P < 0.05) increased while HDL-cholesterol and triglyceride significantly decreased relative to rabbits fed normal diet. The
reciprocal relationship between HDL-cholesterol and LDL-cholesterol in addition to compromised antioxidant enzymes could predispose
exposed animals to coronary heart disease. However, pre-treatment of the diet with vitamins C and E exhibited a protective
role on the toxic effect of crude oil on lipid profile, lipid peroxidation as well as antioxidant enzymes. The order of protection
was vitamin E + C > vitamin E > vitamin C. These observations seemed to suggest that the protective role of vitamins C and
E is synergistic. The protective role of the vitamins is probably time-dependent as significant (P < 0.05) restoration of lipid profile as well as antioxidant enzymes activities to control values was effected after four
weeks of exposure. It is therefore suggested that toxic effect of crude oil may be reduced by dietary supplementation of vitamins
C and E. 相似文献
394.
黑龙江省森林病虫害防治工作存在的问题及对策 总被引:2,自引:0,他引:2
简述了黑龙江省森林病虫害防治工作存在的主要问题,分析了制约我省森林病虫害防治的主要因素,提出了病虫害防治的具体方法及对策. 相似文献
395.
Dennis J. Lye 《Journal of the American Water Resources Association》2002,38(5):1301-1306
ABSTRACT: Rainwater harvesting is receiving increased attention worldwide as an alternative source of drinking water. Although collected rainwater is typically consumed without any type of disinfection, the microbial quality of this type of water source can be poor. Around the world, consumers of collected and stored rainwater may be at considerable risk to a variety of infectious diseases. This review presents studies attributing specific risks of diseases to the consumption of contaminated rainwater. Diseases attributed to the consumption of untreated rainwater include bacterial diarrheas due to Salmonella and Campylobacter, bacterial pneumonia due to Legionella, botulism due to Clostridium, tissue helminths, and protozoal diarrheas from Giardia and Cryptosporidium. Simple indicator systems such as fecal coliform measurements may prove to be inadequate for determining microbial risks associated with consumption of water from rainwater catchment systems. 相似文献
396.
The damage effects of oxy free radical and fulvic acid on cultivated chicken embryo chondrocytes were studied. The results show that the growrth of chondrocytes is inhibited and the morphology of the cells altered. The collagen synthesizing capability of the damaged cell changes somewhat. A noteworthy change of the type of collagen synthesized by the abnormal cells was observed by CMC-chromatography and amino acid analysis. The results indicated that the abnonml cells tend to synthesize type I instead of type II collagen, which is synthesized and secreted by the intact chondrocyte. 相似文献
397.
A study on "selenium-health" database in China 总被引:1,自引:0,他引:1
A database for "Se and health" has been established using DATA-TRIEVE data management system on a VAX-11/780 computer. Over 5000 pieces of information including 300 kinds of samples from 28 provinces in China were stored. The information relates to endemk diseases such as Keshan disease, Kaschin-Beck disease, Se-poison disease, cancers, heart disease and so on. The database can be accessed through keywords: samples, province, county, analytical method and the Se-content values can be obtained in tabulated form. The output includes primary statistics of the retrieved data sets. A multi-variable statistic program package featuring in pattern recognition is attached to the system. 相似文献
398.
Kaschin-Beck disease (KBD) could be exogeneous free radical induced endemic osteoarthropathy under conditions of lacking necessary antioxidant defences.especially selenium-cored defence in Chinese eco-en-vironment. Experimental evidences have been provided for the internal relations among previously suggested pathologic factors, i.e., selenium deficiency, organic matters of drinking waterand mycotoxins from contaminated grains, based on the facts that the former is a preventory factor while the others are exogenous freeradical carriers. ESR spectrum shows that these exogenous free radical carriers have a property of semi-quinone compounds and are toxic in in-vitro cartilage cell culture and animal tests in inducing lipid peroxidation process. 相似文献
399.
G. Novelli Dr M. Frontali D. Baldini C. Bosman B. Dallapiccola A. Pachì F. Torcia 《黑龙江环境通报》1989,9(11):759-767
A prenatal diagnosis of adult polycystic kidney disease by DNA testing is reported. Evidence showing a linkage between the disease and the 3′HVR and 24.1 restriction fragment length polymorphisms (RFLPs) on chromosome 16 was obtained in the proband's family by linkage analysis of data and homogeneity testing with Italian families of the linked type. Fetal genotype prediction based on both flanking markers was confirmed by histological and ultrastructural findings in fetal kidneys. 相似文献
400.
Thomas J. Simpson Mitsuhiko Koresawa W. Allen Hogge Wolfgang Holzgreve Dr. Mitchell S. Golbus 《黑龙江环境通报》1987,7(9):639-652
A reliable and sensitive microassay for the measurement of liver glucose-6-phosphatase is described. Human fetal liver was assayed for glucose-6-phosphatase activity from 7.5 to 24 weeks of gestation and was found to have a mean activity of 2.11 nmol per min per mg of protein. This was approximately 30 per cent of the postnatal controls assayed by the same method, but there was no evidence of a change in activity during the gestational period examined. If fetal liver tissue can be reliably obtained, it may be possible to determine a deficiency of glucose-6-phosphatase in fetuses who are at risk. 相似文献