全文获取类型
收费全文 | 14795篇 |
免费 | 100篇 |
国内免费 | 65篇 |
专业分类
安全科学 | 288篇 |
废物处理 | 760篇 |
环保管理 | 1186篇 |
综合类 | 2274篇 |
基础理论 | 3363篇 |
环境理论 | 7篇 |
污染及防治 | 4029篇 |
评价与监测 | 1218篇 |
社会与环境 | 1774篇 |
灾害及防治 | 61篇 |
出版年
2023年 | 102篇 |
2022年 | 252篇 |
2021年 | 235篇 |
2020年 | 104篇 |
2019年 | 138篇 |
2018年 | 309篇 |
2017年 | 296篇 |
2016年 | 445篇 |
2015年 | 271篇 |
2014年 | 538篇 |
2013年 | 1244篇 |
2012年 | 589篇 |
2011年 | 702篇 |
2010年 | 578篇 |
2009年 | 571篇 |
2008年 | 718篇 |
2007年 | 751篇 |
2006年 | 671篇 |
2005年 | 546篇 |
2004年 | 523篇 |
2003年 | 490篇 |
2002年 | 430篇 |
2001年 | 512篇 |
2000年 | 365篇 |
1999年 | 210篇 |
1998年 | 116篇 |
1997年 | 141篇 |
1996年 | 118篇 |
1995年 | 153篇 |
1994年 | 141篇 |
1993年 | 123篇 |
1992年 | 117篇 |
1991年 | 122篇 |
1990年 | 140篇 |
1989年 | 111篇 |
1988年 | 97篇 |
1987年 | 93篇 |
1986年 | 98篇 |
1985年 | 91篇 |
1984年 | 96篇 |
1983年 | 82篇 |
1982年 | 96篇 |
1980年 | 75篇 |
1979年 | 78篇 |
1977年 | 58篇 |
1974年 | 62篇 |
1973年 | 60篇 |
1972年 | 67篇 |
1964年 | 69篇 |
1958年 | 66篇 |
排序方式: 共有10000条查询结果,搜索用时 342 毫秒
11.
Francisco M. Baena-Moreno Mónica Rodríguez-Galán Fernando Vega Luis F. Vilches Benito Navarrete 《International Journal of Green Energy》2019,16(5):401-412
Biomethane production through biogas upgrading is a promising renewable energy for some industries which could be part of the equilibrium needed with fossil fuels consumption to achieve a sustainable society. This paper presents a comprehensive list of biogas upgrading technologies focused on carbon dioxide removal as well as recent advances reported by researcher with wide expertise in this topic. Additionally, an extensive costs–performance comparison among the technologies studied is discussed. Among the different alternatives, chemical scrubbing stood out to achieve high biomethane purities while cryogenic technologies proved to be effective against methane losses. Regarding the different costs, water scrubbing and membrane separation seem to be the most affordable techniques. 相似文献
12.
Goettems-Fiorin Pauline Brendler Costa-Beber Lilian Corrêa dos Santos Jaíne Borges Friske Paula Taís Sulzbacher Lucas Machado Frizzo Matias Nunes Ludwig Mirna Stela Rhoden Cláudia Ramos Heck Thiago Gomes 《Environmental science and pollution research international》2019,26(20):20581-20594
Environmental Science and Pollution Research - The reduction of estrogen levels, as a result of menopause, is associated with the development of metabolic diseases caused by alterations in... 相似文献
13.
Rui Galhano dos Santos Noemi F. Acero Sandro Matos Ricardo Carvalho Mário Vale Ana C. Marques João C. Bordado Maria M. Mateus 《Journal of Polymers and the Environment》2018,26(1):91-100
The use of petroleum-derived products should be avoided regarding the principles of green and sustainable chemistry. The work reported herein, is aimed at the liquefaction of pine shavings for the production of an environmentally-friendly polyol suitable to be used in the formulations of sprayable polyurethane foams. The biopolyols were obtained in high yield and were used to replace those derived from fossil sources, to produce more “greener” polyurethane foams and therefore, less dependent on petroleum sources, since the polyol component was substituted by products resulting from biomass liquefaction. The partial and fully exchange of the polyols was accomplished, and the results compared with a reference foam. The foams were afterward, chemical, physical, morphological, and mechanically characterized. The complete replacement of polyether polyol and polyol polyester has presented some similar characteristics as that used as a reference, validating that the path chosen for the development of more sustainable materials is on the right track for the contribution to a cleaner world. 相似文献
14.
V. Vijayasree Hebsy Bai S. Naseema Beevi Thomas Biju Mathew Thomas George George Xavier 《Environmental monitoring and assessment》2015,187(5):299
Dissipation and decontamination of chlorantraniliprole (Coragen 18.5 SC) in brinjal and okra fruits were studied following field application at single and double doses of 30 and 60 g ai ha?1, and the residues of the insecticide was estimated using LC-MS/MS. Initial residues of chlorantraniliprole at single and double doses on the fruits of brinjal were 0.72 and 1.48 mg kg?1, while on okra fruits, the residues were 0.48 and 0.91 mg kg?1, respectively. The residues reached below detectable level of 0.01 mg kg?1 on the 10th day. Half-life of chlorantraniliprole at 30 and 60 g ai ha?1 on brinjal was 1.58 and 1.80 days with the calculated waiting period of 0.69 and 2.38 days, whereas on okra, the values were 1.60 and 1.70 and 0 and 1.20 days, respectively. The extent of removal of chlorantraniliprole using simple decontaminating techniques at 2 h and 3 days after spraying was 40.99–91.37 % and 29.85–89.12 %, respectively, from brinjal fruits and 47.78–86.10 % and 41.77–86.48 %, respectively, from okra fruits. 相似文献
15.
The effects of Cu2+, Cd2+, and Ni2+ at low and high concentrations (0.025 and 0.25 mg/ml) on the accumulation capacity, the state of the pigment complex, and photosynthesis rate have been studied in model experiments with three floating hydrophytes (Hydrocharis morsus-ranae L., Lemna gibba L., and Potamogeton natans L.) and four submerged hydrophytes (Elodea canadensis Michx., Lemna trisulka L., Ceratophyllum demersum L., and Potamogeton lucens L.). Copper and cadmium are especially toxic at the concentrations studied. The effect of Cu2+ was the strongest in hydatophytes, and the effect of Cd2+, in pleustophytes. It is hypothesized that the differences between hydrophytes with respect to accumulation of metals and decrease in photosynthesis rate may cause predominant elimination of submerged species. Therefore, changes in the species structure of hydrophyte communities may be expected in waters polluted with metals. 相似文献
16.
Quantitative methods have been applied to the study of floristic structure and diversity in Samarskaya Luka. The results show that Samarskaya Luka is a floristically heterogeneous area in which six elementary floras can be distinguished. This area has been assessed as a floristically autonomous formation, and its floristic representativeness was estimated. 相似文献
17.
F. Pricope Ştefănescu G. Tiţescu I. Cărăuş D. Ureche 《Environmental Chemistry Letters》2003,1(2):149-151
During the artificial reproduction of salmonides, the fecundity can be increased either by improving the viability of spermatozoa,
or by extending the time period during which a roe micropile remains open, thus allowing its fecundation. Practically, this
can be achieved by the use of some fertilising techniques suitable for fish species. Here, we show that the reproduction of
rainbow trout in a 1:1 solution of deuterium-depleted water and distilled water led to a significant increase in survival
of roes during their embryonic development. Moreover, the addition of glucose and fructose into the deuterium-depleted fertilising
solutions led to a further increase in roe survival during embryonic development. The increase in survival is mainly explained
by an increase in the motility of spermatozoa. 相似文献
18.
19.
A transition zone in the otoliths of orange roughy (Hoplostethus atlanticus) is described where annulus width decreases markedly. For fish sampled at spawning time, the relationship between gonad stage
and the presence or absence of a transition zone is consistent with the hypothesis that this zone marks the onset of maturity,
if allowance is made for some error in gonad staging and identification of the zone. Another data set from a non-spawning
area after the spawning season is not consistent with the hypothesis. However, these latter data are considered less reliable
because of the small size of the fish in the sample and difficulties in determining, outside the spawning season, whether
a fish has been reproductively active. This hypothesis was used to provide estimates of the median age (30 yr) and length
(31 cm) at the onset of maturity for the Chatham Rise, New Zealand population. These estimates are unaffected by the biases
associated with the usual ogive method of estimation.
Received: 27 June 1997 / Accepted: 1 July 1997 相似文献
20.
I Chu D C Villeneuve B McDonald V E Secours V E Valli 《Journal of environmental science and health. Part. B》1987,22(3):303-317
Pentachlorotoluene (PCT) and pentabromotoluene (PBT) are environmental contaminants detected in the Great Lakes ecosystem. In view of the paucity of toxicity data and the potential for human exposure, a subacute (28 day) and a subchronic (91 day) study were conducted in the rat. In the subacute study, groups of 10 male and 10 female rats were fed the diet containing PCT or PBT at 0, 0.5, 5.0, 50 or 500 ppm for 28-days. In the subchronic study, the group size was increased to 15, the dose levels were 0, 0.05, 0.5, 5.0, 50 and 500 ppm in the diet and the exposure period was 91 days. Growth rate and food consumption were not affected by exposure to either chemical in the subacute and subchronic study. Clinical observations revealed no abnormalities. Decreased hemoglobin was observed in female rats fed 5.0 ppm PCT and higher levels in the subacute (28 day) study. In the same study the hematocrit value and erythrocyte numbers of females fed 5.0 or 500 ppm PCT diets were significantly lower than the control. In both subacute and subchronic studies mild dose-dependent histopathological changes were observed in the thyroid, liver and kidney of rats fed PCT and PBT diets. In general male rats were more susceptible than females to the treatment of PCT and PBT. Based on these data, it was concluded that the no observable adverse effect level for PCT was 50 ppm in the diet (3.5 mg/kg b.w./day) and that of PBT was 5.0 ppm (0.35 mg/kg b.w./day). 相似文献