首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4309篇
  免费   34篇
  国内免费   13篇
安全科学   55篇
废物处理   274篇
环保管理   256篇
综合类   696篇
基础理论   880篇
环境理论   4篇
污染及防治   1504篇
评价与监测   422篇
社会与环境   257篇
灾害及防治   8篇
  2023年   46篇
  2022年   134篇
  2021年   132篇
  2020年   52篇
  2019年   54篇
  2018年   165篇
  2017年   118篇
  2016年   221篇
  2015年   116篇
  2014年   249篇
  2013年   429篇
  2012年   263篇
  2011年   263篇
  2010年   204篇
  2009年   151篇
  2008年   237篇
  2007年   240篇
  2006年   216篇
  2005年   149篇
  2004年   120篇
  2003年   109篇
  2002年   93篇
  2001年   59篇
  2000年   47篇
  1999年   34篇
  1998年   15篇
  1997年   12篇
  1996年   11篇
  1995年   24篇
  1994年   16篇
  1993年   12篇
  1991年   8篇
  1990年   10篇
  1989年   9篇
  1982年   10篇
  1970年   7篇
  1967年   8篇
  1966年   11篇
  1965年   16篇
  1964年   28篇
  1963年   13篇
  1962年   17篇
  1961年   13篇
  1960年   13篇
  1959年   30篇
  1958年   30篇
  1957年   20篇
  1956年   18篇
  1955年   18篇
  1954年   7篇
排序方式: 共有4356条查询结果,搜索用时 15 毫秒
861.
Environmental Science and Pollution Research - Copper (Cu) can be toxic to vegetables when it is absorbed and accumulated at large concentrations, a fact that increases the risk of excessive...  相似文献   
862.

Heterogeneous photocatalysis is highlighted to treat volatile organic compound (VOC) emission. Then, this work analysed the influence of palladium (Pd) content loaded in TiO2 on n-octane and iso-octane photodegradation. For this, TiO2 was loaded with Pd in different contents: 0.4%, 0.7%, and 1.0%. The samples were characterized, and the photodegradation experiments were conducted by Pd/TiO2/UV process. The characterization analyses showed that the metal presence did not change the catalyst structure or its surface area; however, it reduced the bandgap energy. The photocatalytic results proved that palladium improved n-octane degradation from 62% (pure TiO2) to 92.6% (0.4%Pd/TiO2) and, iso-octane degradation enhanced from 59% (pure TiO2) to 90.6% (0.7%Pd/TiO2); all results were obtained in the space time of 39 s. Therefore, 0.4%Pd/TiO2 and 0.7%Pd/TiO2 showed better oxidation results to degradation n-octane and iso-octane, respectively. The kinetic model of pseudo-first order showed a good fit for the data of both VOCs. Heterogeneous photocatalysis with Pd/TiO2 showed to be an adequate technique to reduce VOCs emission.

  相似文献   
863.
Environmental Science and Pollution Research - The following work provides a perspective on the potential application of solar heterogeneous photocatalysis, which is a nonselective advanced...  相似文献   
864.

During gestation, essential and non-essential trace elements are transferred from the pregnant females to embryos. This study aimed to determine and compare the concentrations of seven essential trace elements (Fe, Zn, Se, Cu, Mn, Cr, Co) and six non-essential trace elements (As, Cd, V, U, Tl, Ag) in the muscle and the liver of a Munk’s pygmy devil ray pregnant female, Mobula munkiana, and its embryo. Transfer evidence of essential and non-essential trace elements was detected in M. munkiana tissues. Arsenic was found in elevated concentrations in the pregnant female and the embryo tissues. Elevated levels of Cd, V, U, and Ag were found in the pregnant female liver, but were minimal in the embryo tissue. This is the first study to investigate maternal transfer of essential and non-essential trace elements in these species and their reproductive strategy.

  相似文献   
865.
Environmental Science and Pollution Research - Activated carbon prepared from grape branches was used as a remarkable adsorbent to uptake naproxen and treat a synthetic mixture from aqueous...  相似文献   
866.
Environmental Science and Pollution Research - Mycotoxins are toxic metabolites of filamentous fungi; they are common contaminants in numerous foods and beverages. Cyclodextrins are ring-shaped...  相似文献   
867.
Environmental Science and Pollution Research - Cadmium (Cd) is known for its many toxic effects on male population such as hypogonadism and fertility difficulties, which are oftenly associated with...  相似文献   
868.
Environmental Science and Pollution Research - This paper discussed the possibility of replacing the internal combustion engine of the series plug-in hybrid electric vehicle (PHEV) powered by...  相似文献   
869.
Environmental Modeling & Assessment - Evapotranspiration (ET) plays an important role in agricultural water management and crop modeling. The highest mean annual ET values (889–1016 mm)...  相似文献   
870.
Temporally variable production of seed crops by perennial plants (masting) has been hypothesized to be a valuable mechanism in the reduction of seed predation by satiating and starving seed consumers. To achieve these benefits, coexisting species subjected to the same predator would benefit from a similar pattern of seeding fluctuation over time that could lead to a reduction in predation at the within-species level. We tested for the existence of an environmental factor enforcing synchrony in acorn production in two sympatric Mediterranean oaks (Quercus ilex and Q. humilis) and the consequences on within-species and between-species acorn predation, by monitoring 15 mixed forests (450 trees) over seven years. Acorn production in Q. ilex and Q. humilis was highly variable among years, with high population variability (CVp) values. The two species exhibited a very different pattern across years in their initial acorn crop size (sum of aborted, depredated, and sound acorns). Nevertheless, interannual differences in summer water stress modified the likelihood of abortion during acorn ripening and enforced within- and, particularly, between-species synchrony and population variability in acorn production. The increase in CVp from initial to mature acorn crop (after summer) accounted for 33% in Q. ilex, 59% in Q. humilis, and 60% in the two species together. Mean yearly acorn pre-dispersal predation by invertebrates was considerably higher in Q. humilis than in Q. ilex. Satiation and starvation of predators was recorded for the two oaks, and this effect was increased by the year-to-year variability in the size of the acorn crop of the two species combined. Moreover, at a longer time scale (over seven years), we observed a significant reduction in the mean proportion of acorns depredated for each oak and the variability in both species' acorn production combined. Therefore, our results demonstrate that similar patterns of seeding fluctuation over time in coexisting species mediated by an environmental cue (summer drought) may contribute to the reduction of the impact of seed predation at a within-species level. Future research should be aimed at addressing whether this process could be a factor assisting in the coexistence of Q. ilex and Q. humilis.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号