全文获取类型
收费全文 | 162篇 |
免费 | 9篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 3篇 |
环保管理 | 48篇 |
综合类 | 21篇 |
基础理论 | 48篇 |
环境理论 | 3篇 |
污染及防治 | 21篇 |
评价与监测 | 6篇 |
社会与环境 | 8篇 |
灾害及防治 | 8篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 8篇 |
2017年 | 13篇 |
2016年 | 11篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 16篇 |
2012年 | 6篇 |
2011年 | 14篇 |
2010年 | 10篇 |
2009年 | 3篇 |
2008年 | 12篇 |
2007年 | 16篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 1篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1991年 | 1篇 |
1987年 | 1篇 |
排序方式: 共有173条查询结果,搜索用时 31 毫秒
161.
162.
163.
Kate F. Lankin Myron A. Peck Lawrence J. Buckley David A. Bengtson 《Marine Biology》2008,155(5):461-472
Rates of routine respiration (R
R, μl O2 fish−1 h−1) and total ammonia nitrogen excretion (E
R, μg NH4–N + NH3–N fish−1 h−1) were measured on larval and juvenile haddock (Melanogrammus aeglefinus) to ascertain how energy losses due to metabolism were influenced by temperature (T), dry body mass (M
D, mg) and specific growth rate (SGR, % per day). R
R and E
R increased with M
D according to y = a · M
D
b
with b-values of 0.96, 0.98, 1.14, and 0.89, 0.78, 0.74, respectively, at 10, 7, and 4°C, respectively. Multiple regressions explained
98% of the variability in the combined effects of M
D and T on R
R and E
R in larval haddock: R
R = 0.97 · M
D
0.98 · e0.092 · T
; E
R = 0.06 · M
D
0.79 · e0.092 · T
. In young juvenile (24–30 mm standard length) haddock, R
R tended to decline (P = 0.06) and E
R significantly declined (P = 0.02) with increasing SGR. O:N ratios significantly increased with increasing SGR suggesting that N was spared in relatively
fast-growing individuals. Our results for young larval and juvenile haddock suggest: (1) nearly isometric scaling of R
R with increasing body size, (2) allometric scaling of E
R with increasing body size, (3) Q
10 values of 2.5 for both R
R and E
R, (4) metabolic differences in substrate utilization between relatively fast- and slow-growing individuals, and (5) that rates
of routine energy loss and growth were not positively related. The measurements in this study will provide robust parameter
estimates for individual-based models that are currently being utilized to investigate how variability in climatic forcing
influences the vital rates of early life stages of haddock. Our results also stress that inter-individual differences in rates
of energy loss should not be overlooked as a factor influencing growth variability among individuals. 相似文献
164.
165.
Petra Quillfeldt Inga Träger Kate Griffiths Katherine L. Buchanan Juan F. Masello 《Behavioral ecology and sociobiology》2007,61(5):793-800
Mass differences between the sexes of dimorphic bird species often appear early in the nestling development. But how do adults know how much to feed a chick in a sexually dimorphic species? Do chicks of the heavier sex beg more? We studied begging in Cory’s shearwaters Calonectris diomedea, a species with heavier adult and juvenile males than females. We found that begging rates and call numbers were not different between male and female chicks, but parameters of begging intensity differed between the sexes in their relationship to chick body condition. For the same body condition, males had significantly higher begging call numbers and rates. Acoustical parameters, which were analysed semi-automatically, included the lengths of call and silence intervals, the minimum, mean and maximum frequency in a call and the number of frequency peaks within a call. We found no consistent differences of acoustic begging call elements between the sexes. Male and female chicks did not differ in the levels of the steroid hormones testosterone or corticosterone in the second quarter of the nestling period, and the mechanism leading to sex-related differences in begging rates for a given body condition remains unknown. 相似文献
166.
Fu-Lin Evelyn Chu Eric D. Lund Paul R. Littreal Kate E. Ruck Ellen Harvey Jean-René Le Coz Yanic Marty Jeanne Moal Philippe Soudant 《Marine Biology》2009,156(2):155-169
The kinetics and efficiency of sterol production and bioconversion of phytosterols in two heterotrophic protists Oxyrrhis marina and Gyrodinium dominans were examined by feeding them two different algal species (Rhodomonas salina and Dunaliella tertiolecta) differing in sterol profiles. R. salina contains predominantly brassicasterol (≅99%) and <2% cholesterol. The major sterols in D. tertiolecta are ergosterol (45–49%), 7-dehydroporiferasterol (29–31%) and fungisterol (21–26%). O. marina fed R. salina metabolized dietary brassicasterol to produce 22-dehydrocholesterol and cholesterol. O. marina fed D. tertiolecta metabolized dietary sterols to produce cholesterol, 22-dehydrocholesterol, brassicasterol and stigmasterol. G. dominans fed either R. salina or D. tertiolecta metabolized dietary sterols to make cholesterol, brassicasterol and a series of unknown sterols. When protists were fed R. salina, which contains cholesterol, the levels of cholesterol were increased to a magnitude of nearly 5- to 30-fold at the phytoplankton-heterotrophic
protist interface, equivalent to a production of 172.5 ± 16.2 and 987.7 ± 377.7 ng cholesterol per mg R. salina carbon consumed by O. marina and G. dominans, respectively. When protists were fed D. tertiolecta, which contains no cholesterol, a net production of cholesterol by the protists ranged from 123.2 ± 30.6 to 871.8 ± 130.8 ng
per mg algal C consumed. Cholesterol is not only the dominant sterol, but a critical precursor for many physiologically functional
biochemicals in higher animal. As intermediates, these heterotrophic protists increase the amount of cholesterol at the phytoplankton–zooplankton
interface available to higher trophic levels relative to zooplankton feeding on algae directly. 相似文献
167.
168.
Ashmore J Babister E Corsellis T Fowler J Kelman I McRobie A Manfield P Spence R Vitale A Battilana R Crawford K 《Disasters》2003,27(4):273-287
The diversity of shelters used in transitional settlements for internally displaced persons (IDPs) in Herat, Afghanistan is described. The information is based on a field survey undertaken in March 2002 and highlights the adaptation techniques, which IDPs undertake to improve any provided shelter. Potential areas for improvement are indicated; for example, the possibility for using insulated, demountable liners to prevent cold-related deaths without sacrificing shelter flexibility along with the likely need for better agency coordination of the shelter responses they provide. The wider context in which the technical recommendations would be implemented must also be considered. Such issues include agency resources, political impediments to providing the desired option, and the preference of many IDPs that the best shelter would be their home. 相似文献
169.
Kate Millar 《Journal of Agricultural and Environmental Ethics》2007,20(4):407-410
170.
Kate Millar Erik Thorstensen Sandy Tomkins Ben Mepham Matthias Kaiser 《Journal of Agricultural and Environmental Ethics》2007,20(1):53-63
A number of EU institutions and government committees across Europe have expressed interest in developing methods and decision-support
tools to facilitate consideration of the ethical dimensions of biotechnology assessment. As part of the work conducted in
the EC supported project on ethical tools (Ethical Bio-TA Tools), a number of ethical frameworks with the potential to support
the work of public policy decision-makers has been characterized and evaluated. One of these potential tools is the Delphi
method. The Delphi method was originally developed to assess variables that are intangible and/or shrouded in uncertainty
by drawing on the knowledge and abilities of a diverse group of experts through a form of anonymous and iterative consultation.
The method has hitherto been used by a diversity of practitioners to explore issues such as technology assessment, environmental
planning, and public health measures. From the original (classical) Delphi, a family of Delphi-related processes has emerged.
As a result of the evaluation of the various Delphi processes, it is proposed that the classical method can be further developed
and applied as a form of ethical framework to assist policy-makers. Through a series of exercises and trials, an Ethical Delphi
has been developed as a potential approach for characterizing ethical issues raised by the use of novel biotechnologies. Advantages
and disadvantages of the method are discussed. Further work is needed to develop the procedural aspects of the Ethical Delphi
method and to test its use in different cultural contexts. However, utilizing an ethical framework of this type combines the
advantages of a methodical approach to capture ethical aspects with the democratic virtues of transparency and openness to
criticism. Ethical frameworks such as the Ethical Delphi should contribute to better understanding of and decision-making
on issues that involve decisive ethical dimensions. 相似文献