全文获取类型
收费全文 | 1918篇 |
免费 | 21篇 |
国内免费 | 29篇 |
专业分类
安全科学 | 80篇 |
废物处理 | 131篇 |
环保管理 | 175篇 |
综合类 | 292篇 |
基础理论 | 325篇 |
污染及防治 | 635篇 |
评价与监测 | 188篇 |
社会与环境 | 131篇 |
灾害及防治 | 11篇 |
出版年
2024年 | 2篇 |
2023年 | 29篇 |
2022年 | 68篇 |
2021年 | 77篇 |
2020年 | 37篇 |
2019年 | 33篇 |
2018年 | 82篇 |
2017年 | 79篇 |
2016年 | 103篇 |
2015年 | 61篇 |
2014年 | 94篇 |
2013年 | 190篇 |
2012年 | 132篇 |
2011年 | 140篇 |
2010年 | 102篇 |
2009年 | 83篇 |
2008年 | 119篇 |
2007年 | 96篇 |
2006年 | 106篇 |
2005年 | 88篇 |
2004年 | 62篇 |
2003年 | 39篇 |
2002年 | 32篇 |
2001年 | 13篇 |
2000年 | 6篇 |
1999年 | 11篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1979年 | 2篇 |
1966年 | 2篇 |
1962年 | 2篇 |
1961年 | 2篇 |
1960年 | 2篇 |
1959年 | 2篇 |
1953年 | 2篇 |
1929年 | 1篇 |
1928年 | 2篇 |
排序方式: 共有1968条查询结果,搜索用时 31 毫秒
421.
422.
Fetomaternal haemorrhage (FMH) was studied after 46 cordocenteses. α-Fetoprotein (AFP) concentration and Kleihauer staining of maternal blood, taken both before and after the procedure, revealed increases in AFP values of more than 40 per cent in 30 per cent of the patients examined; fetal haemorrhage of more than 0.25 ml was detected in 46 per cent of the cases by the Kleihauer test. In the second trimester of pregnancy both techniques are comparable, while in the third trimester the Kleihauer technique appears to be more sensitive in detecting FMH after cordocentesis. An anterior position of the placenta is a risk factor for FMH. 相似文献
423.
Plant Succession, Landscape Management, and the Ecology of Frugivorous Birds in Abandoned Amazonian Pastures 总被引:11,自引:0,他引:11
From towers constructed at the interface between second-growth forest and an active and an abandoned pasture, we observed inter-habitat movements of fruit-eating birds in eastern Amazônia. The abandoned pasture was composed of grasses and forbs with a scattering of shrubs and small trees. The active pasture contained a low, uniform bed of grass. A total of 47 frugivorous bird species was recorded in the second-growth forest. We observed that 18 of these species frequented the adjacent abandoned pasture but only 3 were found in the adjacent active pasture. Fruit-eating birds flying from second-growth forest typically spent only a few minutes in the abandoned pasture, and their movements were generally restricted to a pasture belt of 1–80 m along the border with the second-growth forest. Most inter-habitat movement occurred during the rainy season, which coincided with a peak in fruit availability in the abandoned pasture. Just three bird species, Ramphocelus carbo, Tachyphonus rufus , and Thraupis episcopus , accounted for an estimated 70% of the total movement of frugivores between the second-growth forest and the abandoned pasture. All three species spent most of their time in the abandoned pasture foraging on shrubs and trees but exhibited differences in their preference for specific habitat elements and in their seed-defecation habits. An understanding of bird behaviors in altered landscapes provides important information to planners and policy makers concerned with protecting regional biodiversity and maintaining landscape integrity. This research provides a rationale for placing limits on the size of clearings in the Brazilian Amazon. 相似文献
424.
425.
Maria Grazia Amoroso Antonio Luca Langellotti Valeria Russo Anna Martello Marina Monini Ilaria Di Bartolo Giovanni Ianiro Denise Di Concilio Giorgio Galiero Giovanna Fusco 《Food and environmental virology》2020,12(1):48-57
Bivalve mollusks as filter-feeders concentrate in their digestive tissue microorganisms likely present in the harvesting water, thus becoming risky food especially if consumed raw or poorly cooked. To eliminate bacteria and viruses eventually accumulated, they must undergo a depuration process which efficacy on viruses is on debate. To better clarify the worth of the depuration process on virus elimination from mussels, in this study we investigated rotavirus kinetics of accumulation and depuration in Mytilus galloprovincialis experimentally contaminated. Depuration process was monitored for 9 days and virus residual presence and infectivity were evaluated by real time quantitative polymerase chain reaction, cell culture and electron microscopy at days 1, 2, 3, 5, 7, 9 of depuration. Variables like presence of ozone and of microalgae feeding were also analyzed as possible depuration enhancers. Results showed a two-phase virus removal kinetic with a high decrease in the first 24 h of depuration and 5 days necessary to completely remove rotavirus. 相似文献
426.
427.
Maria Kobel 《Die Naturwissenschaften》1928,16(23):457-460
428.
429.
430.
Juggling work and family responsibilities when involuntarily working more from home: A multiwave study of financial sales professionals 下载免费PDF全文
Laurent M. Lapierre Elianne F. van Steenbergen Maria C. W. Peeters Esther S. Kluwer 《组织行为杂志》2016,37(6):804-822
Using multiwave survey data collected among 251 financial sales professionals, we tested whether involuntarily working more from home (teleworking) was related to higher time‐based and strain‐based work‐to‐family conflict (WFC). Employees' boundary management strategy (integration vs. segmentation) and work–family balance self‐efficacy were considered as moderators of these relationships. Data were collected one month before, three months after, and 12 months after the implementation of a new cost‐saving policy that eliminated employees' access to office space in a centralized work location. The policy resulted in employees being forced to work more from home. A voluntary telework program had been in effect before the new policy, implying that working more from home as a result of the new policy was involuntary in nature. Results revealed that involuntarily working more from home was associated with higher strain‐based WFC but not higher time‐based WFC. However, moderator analyses revealed that the positive association between involuntarily working more from home and both types of WFC was significantly stronger among employees with weaker self‐efficacy in balancing work and family. Boundary management strategy had no detectable moderating effect. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献