全文获取类型
收费全文 | 6610篇 |
免费 | 47篇 |
国内免费 | 33篇 |
专业分类
安全科学 | 139篇 |
废物处理 | 273篇 |
环保管理 | 561篇 |
综合类 | 981篇 |
基础理论 | 1379篇 |
环境理论 | 3篇 |
污染及防治 | 1615篇 |
评价与监测 | 543篇 |
社会与环境 | 1167篇 |
灾害及防治 | 29篇 |
出版年
2022年 | 69篇 |
2021年 | 87篇 |
2020年 | 41篇 |
2019年 | 57篇 |
2018年 | 121篇 |
2017年 | 140篇 |
2016年 | 170篇 |
2015年 | 110篇 |
2014年 | 224篇 |
2013年 | 540篇 |
2012年 | 245篇 |
2011年 | 290篇 |
2010年 | 232篇 |
2009年 | 267篇 |
2008年 | 317篇 |
2007年 | 352篇 |
2006年 | 279篇 |
2005年 | 268篇 |
2004年 | 247篇 |
2003年 | 227篇 |
2002年 | 212篇 |
2001年 | 247篇 |
2000年 | 199篇 |
1999年 | 90篇 |
1998年 | 67篇 |
1997年 | 74篇 |
1996年 | 61篇 |
1995年 | 81篇 |
1994年 | 66篇 |
1993年 | 56篇 |
1992年 | 57篇 |
1991年 | 59篇 |
1990年 | 71篇 |
1989年 | 54篇 |
1988年 | 42篇 |
1987年 | 38篇 |
1986年 | 46篇 |
1985年 | 46篇 |
1984年 | 51篇 |
1983年 | 36篇 |
1982年 | 46篇 |
1981年 | 36篇 |
1980年 | 44篇 |
1979年 | 44篇 |
1975年 | 30篇 |
1974年 | 30篇 |
1973年 | 33篇 |
1972年 | 39篇 |
1971年 | 30篇 |
1969年 | 31篇 |
排序方式: 共有6690条查询结果,搜索用时 15 毫秒
221.
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
222.
223.
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
224.
Dr. Mertin haben wir für seine Hilfe bei der Interpretation der elektronenmikroskopischen Aufnahmen, der Deutschen Forschungsgemeinschaft und dem Fonds der Chemischen Industrie für ihre finanzielle Unterstützung zu danken. 相似文献
225.
226.
227.
228.
229.
I. Shagina H. L. Dadali V. P. Sitnikov V. V. Pugachev N. A. Malygina O. V. Evgrafov 《黑龙江环境通报》1995,15(1):27-34
Ninety-two families with spinal muscular atrophy (SMA) applied for genetic counselling and further prenatal diagnosis. To minimize expenses, only one tightly linked informative marker was determined in the course of preliminary examination, and non-radioactive allele detection was preferably used. Four prenatal diagnoses of SMA type I, four of SMA type II, and one of SMA type III were made. This trial programme shows the considerable requirements, importance, and potential effectiveness of prenatal prediction of SMA in Russia. 相似文献
230.
N. H. Ravindranath Rajiv K. Chaturvedi N. V. Joshi R. Sukumar Jayant Sathaye 《Mitigation and Adaptation Strategies for Global Change》2011,16(2):211-227
Climate change is projected to impact forest ecosystems, including biodiversity and Net Primary Productivity (NPP). National
level carbon forest sector mitigation potential estimates are available for India; however impacts of projected climate change
are not included in the mitigation potential estimates. Change in NPP (in gC/m2/yr) is taken to represent the impacts of climate change. Long term impacts of climate change (2085) on the NPP of Indian
forests are available; however no such regional estimates are available for short and medium terms. The present study based
on GCM climatology scenarios projects the short, medium and long term impacts of climate change on forest ecosystems especially
on NPP using BIOME4 vegetation model. We estimate that under A2 scenario by the year 2030 the NPP changes by (−5) to 40% across
different agro-ecological zones (AEZ). By 2050 it increases by 15% to 59% and by 2070 it increases by 34 to 84%. However,
under B2 scenario it increases only by 3 to 25%, 3.5 to 34% and (−2.5) to 38% respectively, in the same time periods. The
cumulative mitigation potential is estimated to increase by up to 21% (by nearly 1 GtC) under A2 scenario between the years
2008 and 2108, whereas, under B2 the mitigation potential increases only by 14% (646 MtC). However, cumulative mitigation
potential estimates obtained from IBIS—a dynamic global vegetation model suggest much smaller gains, where mitigation potential
increases by only 6% and 5% during the period 2008 to 2108. 相似文献