全文获取类型
| 收费全文 | 1594篇 |
| 免费 | 35篇 |
| 国内免费 | 16篇 |
专业分类
| 安全科学 | 61篇 |
| 废物处理 | 65篇 |
| 环保管理 | 357篇 |
| 综合类 | 158篇 |
| 基础理论 | 493篇 |
| 环境理论 | 4篇 |
| 污染及防治 | 297篇 |
| 评价与监测 | 106篇 |
| 社会与环境 | 83篇 |
| 灾害及防治 | 21篇 |
出版年
| 2024年 | 7篇 |
| 2023年 | 20篇 |
| 2022年 | 30篇 |
| 2021年 | 38篇 |
| 2020年 | 33篇 |
| 2019年 | 45篇 |
| 2018年 | 38篇 |
| 2017年 | 52篇 |
| 2016年 | 59篇 |
| 2015年 | 55篇 |
| 2014年 | 57篇 |
| 2013年 | 129篇 |
| 2012年 | 72篇 |
| 2011年 | 124篇 |
| 2010年 | 71篇 |
| 2009年 | 89篇 |
| 2008年 | 104篇 |
| 2007年 | 97篇 |
| 2006年 | 79篇 |
| 2005年 | 56篇 |
| 2004年 | 55篇 |
| 2003年 | 52篇 |
| 2002年 | 33篇 |
| 2001年 | 17篇 |
| 2000年 | 17篇 |
| 1999年 | 20篇 |
| 1998年 | 15篇 |
| 1997年 | 14篇 |
| 1996年 | 18篇 |
| 1995年 | 16篇 |
| 1994年 | 20篇 |
| 1993年 | 14篇 |
| 1992年 | 16篇 |
| 1991年 | 8篇 |
| 1990年 | 6篇 |
| 1989年 | 8篇 |
| 1988年 | 7篇 |
| 1987年 | 3篇 |
| 1986年 | 5篇 |
| 1985年 | 2篇 |
| 1984年 | 3篇 |
| 1983年 | 6篇 |
| 1982年 | 6篇 |
| 1981年 | 6篇 |
| 1980年 | 7篇 |
| 1978年 | 4篇 |
| 1976年 | 2篇 |
| 1975年 | 3篇 |
| 1973年 | 2篇 |
| 1957年 | 1篇 |
排序方式： 共有1645条查询结果，搜索用时 15 毫秒
991.
992.
993.
Jarcho–Levin syndrome (JLS) or spondylothoracic dysotosis causes early newborn death from respiratory insufficiency. Prenatal diagnosis is possible using fetal ultrasound, but requires a high level of suspicion and definitive diagnosis may be delayed well into the second trimester. We present a case in which a combination of three-dimensional ultrasound and measurement of nuchal translucency thickness allowed successful detection of recurrent JLS at 12 weeks' gestation. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
994.
995.
The developmental process of neurulation involves a series of coordinated morphological events, which result in conversion of the flat neural plate into the neural tube, the primordium of the entire central nervous system (CNS). Failure of neurulation results in neural tube defects (NTDs), severe abnormalities of the CNS, which are among the commonest of congenital malformations in humans. In order to gain insight into the embryological basis of NTDs, such as spina bifida and anencephaly, it is necessary to understand the morphogenetic processes and molecular mechanisms underlying neural tube closure. The mouse is the most extensively studied mammalian experimental model for studies of neurulation, while considerable insight into underlying developmental mechanisms has also arisen from studies in other model systems, particularly birds and amphibians. We describe the process of neural tube formation, discuss the cellular mechanisms involved and highlight recent findings that provide links between molecular signaling pathways and morphogenetic tissue movements. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
996.
Abdallah M. Adra M.D. Andres A. Mejides Fawwaz A. Salman Helain J. Landy Andrew W. Helfgott 《黑龙江环境通报》1994,14(9):865-867
We report a case of fetal hydrocephalus secondary to a third ventricle choroid plexus papilloma detected by ultrasound at 33 weeks' gestation. The prenatal sonographic and colour flow Doppler findings of this rare fetal intracranial tumour are discussed. 相似文献
997.
998.
Edward Wright Andrew M. Robbins Martha M. Robbins 《Behavioral ecology and sociobiology》2014,68(6):957-970
Socioecological models predict that contest competition for clumped foods can lead to higher energy intake and lower energy expenditure for higher-ranking individuals. Here, we examine the relationships between dominance rank and energy intake and expenditure of female mountain gorillas in Bwindi Impenetrable National Park, Uganda (Gorilla beringei beringei). Bwindi gorillas have weak dominance relationships, feed on nonreproductive plant parts throughout the year, and consume fruit when it is seasonally available. We used behavioral observations on one group of gorillas and nutritional analysis of their major food items to calculate energy intake rates and estimated energy expenditure. Using linear mixed models, we found a significant positive relationship between dominance rank and energy intake rates, due to higher-ranking females having faster ingestion rates, rather than consuming foods with higher energy concentrations. Lower-ranking females did not spend significantly more time feeding to compensate for their lower energy intake rates. Lower-ranking females spent significantly more time traveling than higher-ranking females, leading to a negative relationship between dominance rank and energy expenditure. The combined results revealed a significant positive relationship between dominance rank and energy balance. Higher-ranking females did not spend longer feeding on fruit than lower-ranking ones, and the relationship between dominance rank and energy intake rates was not stronger when fruit was available. According to socioecological models, these results suggest that contest competition may be occurring with both fruit and nonreproductive plant parts, which would be consistent with growing evidence that nonreproductive plant parts can be contestable. 相似文献
999.
Quan H. Nguyen Dung D. Tran Khoi K. Dang Dorien Korbee Luan D. M. H. Pham Lan T. Vu Tang T. Luu Loc H. Ho Phat T. Nguyen Trang T. T. Ngo Dung T. K. Nguyen Andrew Wyatt Maaike van Aalst Thong A. Tran William B. Sea 《Sustainable Development》2020,28(3):448-467
The Vietnamese Mekong Delta (VMD) is one of the most examined deltas in the world given its dynamics, complexity, and vulnerability. In the past decades, the VMD has changed rapidly, especially the land use in relation with the socioeconomic development. National policy has profoundly influenced these changes and the changes have significantly affected local livelihoods. However, these changes are not well reported systematically. In this study, we investigate land‐use changes based on institutional analyses across multiple scales, that is, from national, provincial, to local livelihood based on institutional and sustainability analysis. The results show a strong relationship between legal settings over the last 30 years on land use and livelihood transitions. In addition, the constraints of implementing national legal frameworks at provincial level in practice were identified including effects to local livelihoods. We offer some recommendations for sustainable livelihoods in the VMD, with a focus on increasing socioecological resilience. 相似文献
1000.