全文获取类型
收费全文 | 1101篇 |
免费 | 12篇 |
国内免费 | 20篇 |
专业分类
安全科学 | 24篇 |
废物处理 | 68篇 |
环保管理 | 116篇 |
综合类 | 131篇 |
基础理论 | 271篇 |
环境理论 | 4篇 |
污染及防治 | 357篇 |
评价与监测 | 91篇 |
社会与环境 | 62篇 |
灾害及防治 | 9篇 |
出版年
2023年 | 17篇 |
2022年 | 47篇 |
2021年 | 47篇 |
2020年 | 22篇 |
2019年 | 21篇 |
2018年 | 44篇 |
2017年 | 53篇 |
2016年 | 54篇 |
2015年 | 32篇 |
2014年 | 77篇 |
2013年 | 102篇 |
2012年 | 59篇 |
2011年 | 90篇 |
2010年 | 69篇 |
2009年 | 50篇 |
2008年 | 55篇 |
2007年 | 64篇 |
2006年 | 48篇 |
2005年 | 27篇 |
2004年 | 26篇 |
2003年 | 30篇 |
2002年 | 22篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有1133条查询结果,搜索用时 375 毫秒
691.
Juliana Ferreira Floriano Natan Roberto de Barros José Luiz Ferreira Cinman Rosangela Gonçalves da Silva Augusto Villela Loffredo Felipe Azevedo Borges Ana Maria Queiros Norberto Ana Laura Destro Chagas Bruna Cambraia Garms Carlos Frederico de Oliveira Graeff Rondinelli Donizetti Herculano 《Journal of Polymers and the Environment》2018,26(6):2281-2289
Ketoprofen is an analgesic with potent anti-inflammatory activity against acute inflammation, subacute inflammation, for the acute and long-term treatment of various inflammatory pathologies, as rheumatoid arthritis and colonic adenocarcinoma. In order to minimize the incidence of systemic events related to ketoprofen, the transdermal drug delivery system development has been most important. The advantages of using natural rubber latex membranes include not only the reduction of adverse systemic events, but also the suitability of the low cost of the material together with its physicochemical properties such as flexibility, mechanical stability, surface porosity and water vapor permeability, and besides being a biocompatible material also presents biological activity to stimulate the angiogenesis, being able to be used in tissue repair. This study demonstrated that ketoprofen was successfully incorporated into natural latex membranes for drug delivery. FTIR indicated that the drug did not interact chemically with the membrane. Moreover, the natural latex membranes released 60% of the ketoprofen incorporated in 50 h. SEM images indicated that a portion of the drug was present on the membrane surface, being this portion responsible for the burst release. The tensile tests showed that the addition of the drug into the natural latex membrane did not influence on the polymer mechanical behavior. In addition, drug-natural latex membranes presented no red blood cell damaging effects. Our data shows that the ketoprofen loaded natural latex membranes is a promising system for sustained drug delivery which can be used to minimize the adverse side effects of high dose systemic drug delivery. 相似文献
692.
693.
Cláudia B. Lopes Joana R. Oliveira Luciana S. Rocha Daniela S. Tavares Carlos M. Silva Susana P. Silva Niels Hartog Armando C. Duarte E. Pereira 《Environmental science and pollution research international》2014,21(3):2108-2121
The technical feasibility of using stopper-derived cork as an effective biosorbent towards bivalent mercury at environmentally relevant concentrations and conditions was evaluated in this study. Only 25 mg/L of cork powder was able to achieve 94 % of mercury removal for an initial mercury concentration of 500 μg/L. It was found that under the conditions tested, the efficiency of mercury removal expressed as equilibrium removal percentage does not depend on the amount of cork or its particle size, but is very sensitive to initial metal concentration, with higher removal efficiencies at higher initial concentrations. Ion exchange was identified as one of the mechanisms involved in the sorption of Hg onto cork in the absence of ionic competition. Under ionic competition, stopper-derived cork showed to be extremely effective and selective for mercury in binary mixtures, while in complex matrices like seawater, moderate inhibition of the sorption process was observed, attributed to a change in mercury speciation. The loadings achieved are similar to the majority of literature values found for other biosorbents and for other metals, suggesting that cork stoppers can be recycled as an effective biosorbent for water treatment. However, the most interesting result is that equilibrium data show a very rare behaviour, with the isotherm presenting an almost square convex shape to the concentration axis, with an infinite slope for an Hg concentration in solution around 25 μg/L. 相似文献
694.
Isolation and characterization of a Pseudomonas aeruginosa from a virgin Brazilian Amazon region with potential to degrade atrazine 总被引:1,自引:0,他引:1
Ana Flavia Tonelli Fernandes Michelle Barbosa Partata da Silva Vinicius Vicente Martins Carlos Eduardo Saraiva Miranda Eliana Guedes Stehling 《Environmental science and pollution research international》2014,21(24):13974-13978
The use of pesticides to increase agricultural production can result in the contamination of the environment, causing changes in the genetic structure of organisms and in the loss of biodiversity. This practice is also inducing changes in the rainforest ecosystem. In this work, a Pseudomonas aeruginosa isolated from a preservation soil area of the Brazilian Amazon Forest, without usage of any pesticide, was evaluated for its potential to degrade atrazine. This isolate presented all responsible genes (atzA, atzB, atzC, atzD, atzE, and atzF) for atrazine mineralization and demonstrated capacity to use atrazine as a nitrogen source, having achieved a reduction of 44 % of the initial concentration of atrazine after 24 h. These results confirm gene dispersion and/or a possible contamination of the area with the herbicide, which reinforces global concern of the increase and intensive use of pesticides worldwide. 相似文献
695.
María Oliveira Rosa M. Crujeiras Alberto Rodríguez-Casal 《Environmental and Ecological Statistics》2014,21(1):143-159
Smoothing methods and SiZer (SIgnificant ZERo crossing of the derivatives) are useful tools for exploring significant underlying structures in data samples. An extension of SiZer to circular data, namely CircSiZer, is introduced. Based on scale-space ideas, CircSiZer presents a graphical device to assess which observed features are statistically significant, both for density and regression analysis with circular data. The method is intended for analyzing the behavior of wind direction in the atlantic coast of Galicia (NW Spain) and how it has an influence over wind speed. The performance of CircSiZer is also checked with some simulated examples. 相似文献
696.
697.
Ecological interaction networks are a valuable approach to understanding plant-pollinator interactions at the community level. Highly structured daily activity patterns are a feature of the biology of many flower visitors, particularly provisioning female bees, which often visit different floral sources at different times. Such temporal structure implies that presence/absence and relative abundance of specific flower-visitor interactions (links) in interaction networks may be highly sensitive to the daily timing of data collection. Further, relative timing of interactions is central to their possible role in competition or facilitation of seed set among coflowering plants sharing pollinators. To date, however, no study has examined the network impacts of daily temporal variation in visitor activity at a community scale. Here we use temporally structured sampling to examine the consequences of daily activity patterns upon network properties using fully quantified flower-visitor interaction data for a Kenyan savanna habitat. Interactions were sampled at four sequential three-hour time intervals between 06:00 and 18:00, across multiple seasonal time points for two sampling sites. In all data sets the richness and relative abundance of links depended critically on when during the day visitation was observed. Permutation-based null modeling revealed significant temporal structure across daily time intervals at three of the four seasonal time points, driven primarily by patterns in bee activity. This sensitivity of network structure shows the need to consider daily time in network sampling design, both to maximize the probability of sampling links relevant to plant reproductive success and to facilitate appropriate interpretation of interspecific relationships. Our data also suggest that daily structuring at a community level could reduce indirect competitive interactions when coflowering plants share pollinators, as is commonly observed during flowering in highly seasonal habitats. 相似文献
698.
Patricia N. Pochelon Teresa Lopes da Silva Alberto Reis Antonina dos Santos Henrique Queiroga Ricardo Calado 《Marine Biology》2011,158(12):2825-2833
The present study investigated the existence of inter-individual and within-brood variability in the fatty acid (FA) profile
of developing embryos of Nephrops norvegicus. In all surveyed females (n = 5), the quantitatively most important FAs were as follows: 22:6n-3 (20.8 ± 3.9% average of total FA ± standard error),
18:1n-9 (19.5 ± 2.0%), 16:0 (15.2 ± 3.4%), 20:5n-3 (10.2 ± 1.4%), 16:1n-7 (8.9 ± 1.6%), and 18:1n-7 (5.7 ± 1.3%). Differences
in FA profiles of embryos in the same clutch were assessed using brooding chamber side (left and right) and pleopod (1st and
2nd, 3rd and 4th, and 5th) as predictive factors. There were no significant differences in the FA composition of embryos sampled
from both sides of the brooding chamber in 4 of the 5 surveyed females. However, all females exhibited significant differences
in the FA profiles of embryos sampled from different pleopods. Both saturated FA (SFA) and highly unsaturated FA (HUFA) present
in developing embryos exhibited marked differences along the breeding chamber. Overall, FA reserves appeared to vary significantly
within broods, which can ultimately be reflected on early larval survival. A potential cause for the within-brood variation
recorded in the FA profile of developing embryos include (1) differential female investment during ovarian maturation, mainly
due to variation in food quality/availability; (2) differential lipid catabolism during the incubation period of developing
embryos, as a consequence of embryos position within the female’s brooding chamber; or (3) differential female investment
during ovarian maturation amplified by differential lipid catabolism during the incubation period. 相似文献
699.
Hatchery rearing of the scallop Argopecten purpuratus has resulted in successive generations of scallops not exposed to predators that are less sensitive to and escape more slowly
from predators than wild scallops. The present study examined whether conditioning hatchery-reared A. purpuratus to its natural predator, the sea star Meyenaster gelatinosus, improved its escape responses. Both juvenile and adult A. purpuratus from Tongoy Bay, Chile, were exposed for 7 days to different conditions: (1) continuous predator odor, (2) predator contact
for 30 min three times a day, (3) a combination of the two previous conditions, and (4) no exposure to the predator (control).
After conditioning, we evaluated scallop’s escape responses: reaction time, total clap number, duration of the clapping response,
clapping rate, and the time scallops spent closed when exhausted. Conditioning with contact and odor plus contact (i.e., high
predation risk) resulted in 25 and 50% shorter reaction times of juveniles and adults, respectively. Further, these stimuli
caused juveniles to increase the number of claps and clapping rate. For adults, the time spent closed after exhaustion decreased
by 50 and 63% after conditioning with contact and odor plus contact, respectively. Therefore, it is shown for the first time
that exposure of scallops to increasing predator stimuli enhances escape responses, evidence of threat-sensitive predator
avoidance. 相似文献
700.
Ana Paula Madeira Di Beneditto Cristina Maria Magalhães de Souza Helena Amaral Kehrig Carlos Eduardo Rezende 《Marine Biology》2011,158(10):2209-2217
The feeding preferences of the coastal dolphins Pontoporia blainvillei and Sotalia guianensis in south-eastern Brazil (21o18′S–22o25′S) were assessed through the prey’s index of relative importance (IRI), total mercury
concentration (Hgtot), and stable isotopic (δ15N and δ13C) to compare their efficiency in the discrimination of prey contribution to the predators’ diet. The IRI was the best tool
to describe the dolphins’ preference, while Hgtot and δ15N seemed to be efficient as a trophic marker when the diet is made up of prey of varying sizes, as observed in S. guianensis. Both dolphins presented lighter δ15N than their prey species, which is an unusual pattern. However, as the sample size to isotope ratios analysis was small,
especially to the dolphins, the results should be considered with caution, and further studies are necessary to corroborate
these findings. The δ13C values characterized a typical coastal food chain, confirming the preferential area of these species. 相似文献