全文获取类型
收费全文 | 6869篇 |
免费 | 48篇 |
国内免费 | 40篇 |
专业分类
安全科学 | 149篇 |
废物处理 | 282篇 |
环保管理 | 587篇 |
综合类 | 1006篇 |
基础理论 | 1418篇 |
环境理论 | 3篇 |
污染及防治 | 1736篇 |
评价与监测 | 571篇 |
社会与环境 | 1176篇 |
灾害及防治 | 29篇 |
出版年
2022年 | 100篇 |
2021年 | 107篇 |
2020年 | 52篇 |
2019年 | 70篇 |
2018年 | 127篇 |
2017年 | 157篇 |
2016年 | 185篇 |
2015年 | 115篇 |
2014年 | 235篇 |
2013年 | 564篇 |
2012年 | 251篇 |
2011年 | 305篇 |
2010年 | 238篇 |
2009年 | 275篇 |
2008年 | 328篇 |
2007年 | 358篇 |
2006年 | 287篇 |
2005年 | 274篇 |
2004年 | 256篇 |
2003年 | 235篇 |
2002年 | 214篇 |
2001年 | 250篇 |
2000年 | 202篇 |
1999年 | 91篇 |
1998年 | 68篇 |
1997年 | 74篇 |
1996年 | 61篇 |
1995年 | 81篇 |
1994年 | 67篇 |
1993年 | 57篇 |
1992年 | 57篇 |
1991年 | 60篇 |
1990年 | 72篇 |
1989年 | 54篇 |
1988年 | 43篇 |
1987年 | 38篇 |
1986年 | 46篇 |
1985年 | 47篇 |
1984年 | 51篇 |
1983年 | 37篇 |
1982年 | 46篇 |
1981年 | 36篇 |
1980年 | 44篇 |
1979年 | 45篇 |
1977年 | 31篇 |
1975年 | 31篇 |
1974年 | 31篇 |
1973年 | 33篇 |
1972年 | 39篇 |
1969年 | 31篇 |
排序方式: 共有6957条查询结果,搜索用时 15 毫秒
931.
932.
Philippe Louâpre Stéphanie Llopis Véronique Martel Joan van Baaren 《Die Naturwissenschaften》2014,101(11):875-882
In many insect species, sperm-depleted males (SDMs, i.e. males that have exhausted their sperm after a given number of matings) remain sexually active and continue to mate females. Here, we investigated the behavioural modifications that occur in both sexes of the parasitoid Asobara tabida Nees (Hymenoptera: Braconidae), after matings by fertile males and sperm-depleted males. We show that (i) virgin females, mated females and females mated to a SDM exhibited different behaviours and that (ii) males responded differently to females depending on whether the females had previously mated with an SDM or not. Our findings demonstrate that SDM influenced the reproductive behaviour of both males and females, especially with regard to male responsiveness and female attractiveness. These findings are discussed in the context of adaptive behaviour and fitness maximization in both males and females. 相似文献
933.
934.
935.
936.
937.
N. V. Kovganko Zh. N. Kashkan Yu. G. Chernov S. K. Ananich S. N. Sokolov et al. 《Die Naturwissenschaften》1995,82(5):252-252
XII Ecdysone Workshop July 22–26, 1996 Barcelona, Spain 相似文献
938.
European scale application of atmospheric reactive nitrogen measurements in a low-cost approach to infer dry deposition fluxes 总被引:1,自引:0,他引:1
Y.S. Tang I. Simmons N. van Dijk C. Di Marco E. Nemitz U. Dmmgen K. Gilke V. Djuricic S. Vidic Z. Gliha D. Borovecki M. Mitosinkova J.E. Hanssen T.H. Uggerud M.J. Sanz P. Sanz J.V. Chorda C.R. Flechard Y. Fauvel M. Ferm C. Perrino M.A. Sutton 《Agriculture, ecosystems & environment》2009,133(3-4):183
A European scale network was established in 2006 as part of the NitroEurope Integrated Project to infer reactive nitrogen (Nr) dry deposition fluxes, based on low-cost sampling of gaseous and aerosol species and inferential modelling. The network provides monthly measurements of NH3, NH4+, HNO3 and NO3−, as well as SO2, SO42−, HCl, Cl− and base cations at 58 sites. Measurements are made with an established low-cost denuder methodology (DELTA) as a basis to: (1) examine temporal trends and spatial patterns across Europe, (2) improve and calibrate inferential modelling techniques to estimate exchange of Nr species, (3) provide best estimates of atmospheric dry N deposition, and (4) permit an analysis of net GHG exchange in relation to atmospheric and agricultural N inputs at the European scale. Responsibility for measurements is shared among seven European laboratories. An inter-comparison of the DELTA implementation by 6 laboratories at 4 test sites (Montelibretti, Italy; Braunschweig, Germany; Paterna, Spain and Auchencorth, UK) from July to October 2006 provided training for the laboratories and showed that good agreement was achieved in different climatic conditions (87% of laboratory site-means within 20% of the inter-laboratory median). Results obtained from the first year of measurements show substantial spatial variability in atmospheric Nr concentrations, illustrating the major local (NH3) and regional (HNO3, NO3−, and NH4+) differences in Nr concentrations. These results provide the basis to develop future estimates of site-based Nr dry deposition fluxes across Europe, and highlight the role of NH3, largely of agricultural origin, which was the largest single constituent and will dominate dry Nr fluxes at most sites. 相似文献
939.
C.R. Rodríguez Pleguezuelo V.H. Durn Zuazo J.L. Muriel Fernndez F.J. Martín Peinado D. Franco Tarifa 《Agriculture, ecosystems & environment》2009,134(1-2):79-88
On the coast of Granada (SE, Spain), an economically important area for subtropical fruit cultivation, the crops are grown on orchard terraces. Also, high amounts of fertilizers, often excessive, are used in this type of intensive agriculture. However, each year significant fractions of nutrients taken up by the trees return to the soil by fallen leaves. Using a litter-bag technique, we assessed the decomposition rates and N-release in various types of litter. Our main purpose was to compare two different agroecosystem scenarios: (1) an unaltered slope consisting mainly of a mixture of herbaceous plants (Papaver rhoeas, Convolvulus sp., Malva sylvestris, Reseda phyteuma, Anacyclus sp., Sinapis arvensis, Medicago sp.) among spontaneous perennial woody shrubs (Genista umbellata, Olea europaea, Lavandula officinalis, Phlomis purpurea, Retama sphaerocarpa), and (2) an altered slope cultivated with subtropical trees on terraces: loquat (Eriobotrya japonica), mango (Mangifera indica), avocado (Persea americana), and cherimoya (Annona cherimola), with groundcover plantings of aromatic, medicinal, and melliferous plants (AMMPs) on the taluses of the terraces, which are usually used for erosion control: Lavandula dentata, Thymus mastichina, Satureja obovata, Rosmarinus officinalis, Anthyllis cytisoides. In the leaves from the subtropical crops, we found the highest decomposition rates in cherimoya and the lowest in mango (1.30 and 0.64 years−1, respectively). Leaves from mango and loquat registered initial peaks of N immobilization and later N-release, which was highest in cherimoya and avocado leaves (71.2 and 56.8% of the initial remaining N). In the spontaneous woody shrubs, O. europaea and G. umbellata were the slowest in decomposing (1.18 and 1.01 years−1, respectively) contrary to L. officinalis, which decomposed fastest (2.22 years−1). Only L. officinalis and P. purpurea registered a net N-release at the end of the study. The AMMPs showed different decomposition patterns: L. dentata registered the highest decomposition rates and Rosmarinus the lowest (1.9 and 1.1 years−1, respectively). T. mastichina, L. dentata, and S. obovata had the highest N-release, whereas R. officinalis and A. cytisoides showed N immobilization (183 and 122% of the initial N). Knowledge of the dynamics of nutrient release and litter decomposition will be useful for predicting nutrient availability and nutrient cycles in these types of agroecosystems where subtropical orchards are grown on terraces. 相似文献
940.