全文获取类型
收费全文 | 922篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 36篇 |
废物处理 | 29篇 |
环保管理 | 89篇 |
综合类 | 180篇 |
基础理论 | 254篇 |
环境理论 | 1篇 |
污染及防治 | 214篇 |
评价与监测 | 70篇 |
社会与环境 | 50篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 6篇 |
2022年 | 3篇 |
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 17篇 |
2017年 | 31篇 |
2016年 | 24篇 |
2015年 | 25篇 |
2014年 | 22篇 |
2013年 | 51篇 |
2012年 | 36篇 |
2011年 | 50篇 |
2010年 | 39篇 |
2009年 | 34篇 |
2008年 | 54篇 |
2007年 | 53篇 |
2006年 | 47篇 |
2005年 | 27篇 |
2004年 | 25篇 |
2003年 | 38篇 |
2002年 | 31篇 |
2001年 | 20篇 |
2000年 | 28篇 |
1999年 | 12篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 14篇 |
1994年 | 9篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 14篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 17篇 |
1978年 | 9篇 |
1977年 | 13篇 |
1976年 | 12篇 |
1975年 | 9篇 |
1974年 | 3篇 |
排序方式: 共有928条查询结果,搜索用时 46 毫秒
21.
A protocol for easy storage and later expansion of lymphocyte populations is given. Compared with methods using transformed cell lines, the method has a number of advantages for repeated production of cells for the isolation of DNA in amounts sufficient for use in diagnostic DNA technology. 相似文献
22.
Finn Stener Jørgensen MD 《黑龙江环境通报》1995,15(5):419-429
The aim of the study was to describe the opinion of pregnant women who had accepted or declined an alpha-fetoprotein (AFP) test, not only on AFP screening in general, but also on whether every pregnant woman should be offered amniocentesis (AC)/chorionic villus sampling (CVS) and an ultrasound scan for fetal malformations. An additional aim was to describe pregnant women's attitudes concerning continued research in the prenatal field. The study was performed as a questionnaire study in two regions over a 1-year period from 1 October 1988 to 30 September 1989. Results are based on answers from 3331 women who had taken an AFP test and 336 women who had declined the offer of a test. A total of 79 per cent of the women thought that an AFP test, 70 per cent that an ultrasound scan for fetal malformations, and 26 per cent that AC or CVS should be offered to all pregnant women. Fifty-nine per cent of the women were positive towards continued research in the prenatal field. Women who had had an AFP test were generally much more positive towards screening and research than women who had declined, who were generally against. Women who had left school without a high school degree were on average more positive towards the screening issues than women who had this degree. In conclusion, the results obtained in this study strongly suggest that women's attitudes are very dependent on how the prenatal screening programme is already organized in their local area. 相似文献
23.
24.
Christian Klixbüll Jørgensen 《Die Naturwissenschaften》1982,69(9):420-427
The “constituents” quarks and leptons of matter (with rest-mass) are compared with the historical development of “elements” in chemistry. If unsaturated quarks induce high (and at the moment unpredictable) rest-masses above l0GeV, we have a new view of nuclei comprising (2Z + N) u-quarks and (Z +2N) d-quarks in their low-energy states, without any reference to protons and neutrons as permanent building-blocks. Recent studies of quarks and possible rishons (sub-quarks) and technicolour hadrons are reviewed, and the rôle of identity and cardinality in quantum mechanics analyzed. 相似文献
25.
26.
Niels Gregersen Vibeke Winter Peter K. A. Jensen Anni Holmskov Steen Kølvraa Brage S. Andresen Ernst Christensen Peter Bross Jytte B. Lundemose Dr Markil Gregersen 《黑龙江环境通报》1995,15(1):82-86
Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is a potentially fatal inherited disease with a carrier frequency of approximately 1:100 in most Caucasian populations. The disease is implicated in sudden unexpected death in childhood. A prevalent disease-causing point mutation (A985G) in the MCAD gene has been characterized, thus rendering diagnosis easy in the majority of cases. Since the clinical spectrum of MCAD deficiency ranges from death in the first days of life to an asymptomatic life, there are probably other genetic factors—in addition to MCAD mutations—involved in the expression of the disease. Thus, families who have experienced the death of a child from MCAD deficiency might have an increased risk of a seriously affected subsequent child. In such a family we have therefore performed a prenatal diagnosis on a chorionic villus sample by a highly specific and sensitive polymerase chain reaction (PCR) assay for the G985 mutation. The analysis was positive and resulted in abortion. We verified the diagnosis by direct analysis on blood spots and other tissue material from the aborted fetus and from family members. 相似文献
27.
Methane oxidation in slurry storage surface crusts 总被引:1,自引:0,他引:1
Livestock manure is a significant source of atmospheric methane (CH4), especially during liquid storage. In liquid manure (slurry) storages a surface crust may form naturally, or an artificial surface crust can be established. We investigated whether there is a potential for CH4 oxidation in this environment. Surface crust materials were sampled from experimental storages with cattle slurry (with natural crust) or anaerobically digested cattle slurry (with straw layer) that had been stored with or without a wooden cover. Extracts of surface crust material were incubated with 5.6% CH4 in the headspace, and methanotrophic activity was demonstrated in all four treatments following a 4- to 10-d lag phase. Subsequent incubation of field-moist surface crust material with 350 microL L(-1) CH4 also showed CH4 oxidation, indicating a potential for CH4 removal under practical storage conditions. There was no CH4 oxidation activity during incubation of autoclaved samples. Methane oxidation rates were 0.1 to 0.5 mg kg(-1) organic matter (OM) h(-1), which is comparable with the activity in wetlands and rice paddies. Partial drying increased CH4 oxidation to 0.2 to 1.4 mg kg(-1) OM h(-1), probably as a result of improved diffusivity within the surface crust. Rewetting reversed the stimulation of methanotrophic activity in some treatments, but not in others, possibly due to a decline in CH4 production in anaerobic volumes, or to growth of methanotrophs during incubation. This study presents direct evidence for methanotrophic activity in slurry storages. Measures to ensure crust formation with or without a solid cover appear to be a cost-effective greenhouse gas mitigation option. 相似文献
28.
29.
30.
Anders Malmendal Jesper Givskov Sørensen Johannes Overgaard Martin Holmstrup Niels Chr. Nielsen Volker Loeschcke 《Die Naturwissenschaften》2013,100(5):417-427
We investigated the global metabolite response to artificial selection for tolerance to stressful conditions such as cold, heat, starvation, and desiccation, and for longevity in Drosophila melanogaster. Our findings were compared to data from other levels of biological organization, including gene expression, physiological traits, and organismal stress tolerance phenotype. Overall, we found that selection for environmental stress tolerance changes the metabolomic 1H NMR fingerprint largely in a similar manner independent of the trait selected for, indicating that experimental evolution led to a general stress selection response at the metabolomic level. Integrative analyses across data sets showed little similarity when general correlations between selection effects at the level of the metabolome and gene expression were compared. This is likely due to the fact that the changes caused by these selection regimes were rather mild and/or that the dominating determinants for gene expression and metabolite levels were different. However, expression of a number of genes was correlated with the metabolite data. Many of the identified genes were general stress response genes that are down-regulated in response to selection for some of the stresses in this study. Overall, the results illustrate that selection markedly alters the metabolite profile and that the coupling between different levels of biological organization indeed is present though not very strong for stress selection at this level. The results highlight the extreme complexity of environmental stress adaptation and the difficulty of extrapolating and interpreting responses across levels of biological organization. 相似文献