全文获取类型
收费全文 | 9219篇 |
免费 | 436篇 |
国内免费 | 3010篇 |
专业分类
安全科学 | 592篇 |
废物处理 | 570篇 |
环保管理 | 702篇 |
综合类 | 4623篇 |
基础理论 | 1601篇 |
污染及防治 | 3436篇 |
评价与监测 | 398篇 |
社会与环境 | 388篇 |
灾害及防治 | 355篇 |
出版年
2024年 | 12篇 |
2023年 | 159篇 |
2022年 | 459篇 |
2021年 | 378篇 |
2020年 | 287篇 |
2019年 | 296篇 |
2018年 | 321篇 |
2017年 | 383篇 |
2016年 | 412篇 |
2015年 | 435篇 |
2014年 | 650篇 |
2013年 | 906篇 |
2012年 | 735篇 |
2011年 | 773篇 |
2010年 | 598篇 |
2009年 | 543篇 |
2008年 | 665篇 |
2007年 | 514篇 |
2006年 | 514篇 |
2005年 | 366篇 |
2004年 | 311篇 |
2003年 | 351篇 |
2002年 | 317篇 |
2001年 | 269篇 |
2000年 | 295篇 |
1999年 | 289篇 |
1998年 | 233篇 |
1997年 | 223篇 |
1996年 | 192篇 |
1995年 | 154篇 |
1994年 | 120篇 |
1993年 | 118篇 |
1992年 | 106篇 |
1991年 | 86篇 |
1990年 | 34篇 |
1989年 | 36篇 |
1988年 | 28篇 |
1987年 | 18篇 |
1986年 | 15篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1979年 | 3篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1956年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
961.
陈吉余 《长江流域资源与环境》1995,4(2):106-109
探讨了连接上海,崇明和江苏海门的长江河口桥隧工程在连接河口岛屿间交通,发挥崇明的区位优势,促进地区经济发展以及在上海港建设中的作用。详细论述了越江工程完成后上海新港的扩建,根据河口河水岸线的分布,提出了在横沙岛东滩修建人工岛的设想,最后对几种越江方案进行了分析比较,提出了作者的看法。 相似文献
962.
963.
Sediment cores were collected from two remote subalpine lakes: the rather shallow (1.5 m) Little Ghost Lake at 2040 m elevation and the deeper, Great Ghost Lake (40 m) at 2150 m elevation. Different early diagenesis of metals were observed. the seasonally anoxic hypolimnion drives the annual iron redox cycle and causes the remobilization of metals in the mobile fractions of sediments in the Great Ghost Lake. These result in the redistribution of metals in the mobile fractions of sediment and poor correlation between metal concentrations. in the Little Ghost Lake, the shallow water column is always oxic with less change of metals in the mobile fractions of sediments. As a result, most metals have strong positive correlations with each other.
The distributions of metal/Al ratios, total metal contents and acid-leached metal concentrations in the near-surface sediments of these two lakes suggest that the anthropogenic inputs from the atmospheric fallouts in recent decades are one of the major factors affecting the distributions of metals such as cadmium, lead and, to a lessor extent, zinc. the Pb-206/Pb-207 ratios confirm the anthropogenic lead input in these surface sediments. 相似文献
The distributions of metal/Al ratios, total metal contents and acid-leached metal concentrations in the near-surface sediments of these two lakes suggest that the anthropogenic inputs from the atmospheric fallouts in recent decades are one of the major factors affecting the distributions of metals such as cadmium, lead and, to a lessor extent, zinc. the Pb-206/Pb-207 ratios confirm the anthropogenic lead input in these surface sediments. 相似文献
964.
A laboratory experiment was conducted to test whether anti-predator responses could be induced in the green mussel, Perna viridis, on exposure to waterborne cues from two predators, the muricid gastropod, Thais clavigera, and the portunid crab, Thalamita danae, and from damaged conspecifics. There were five treatments in this study. Aquaria of two treatments housed either Thalamita danae or Thais clavigera. Another three treatments housed only intact mussels, broken and intact mussels, or no mussels. No significant differences were found among these five treatments in final shell weight and tissue dry weight. Induced defensive responses were predator-specific. Experimental mussels exposed to waterborne cues of T. clavigera had a higher percentage increase in shell length, height and width, whereas those exposed to waterborne cues of T. danae had a higher percentage increase in shell width and height. Mussels raised in the presence of crabs developed thicker shell at the umbo and lip margin, whereas mussels raised in the presence of gastropods had thicker shell lip. Predator preference for mussels from the control group and for those pre-exposed to waterborne cues of either of the predators was studied. T. clavigera preferentially selected mussels from the control group, whereas no prey preference was found for T. danae, although shell breaking time for mussels exposed to a crab was longer than that for the control. While the present results should be viewed with caution in the absence of a dietary control, this was the first time that prey handling was shown to be affected by defensive changes in the morphology of mussels.Communicated by T. Ikeda, Hakodate 相似文献
965.
Chen B Li Y Huang GH Huang Y Li Y 《Journal of environmental science and health. Part. B》2004,39(4):613-626
A GIS-aided pesticide loss model (PeLM) was developed to simulate pesticide losses through surface runoff and sediment transport in watershed systems. The PeLM could tackle the movement of eroded soil along with surface runoff as well as the pesticide losses in adsorbed and dissolved phases. The contributions of different soil types in the sediment were also examined. The model was applied to the Kintore Creek Watershed of southern Ontario, Canada. The simulation results were verified through observed data, indicating a correlation level of 0.89-0.98. The results also showed that clay particles usually held the largest share of contributions to pesticide losses through soil erosion. This study is significant in the efforts for modeling nonpoint source pollution in watershed systems. It provides useful information and support for the related decisions of watershed management. 相似文献
966.
Kalingan AE Liao CM Chen JW Chen SC 《Journal of environmental science and health. Part. B》2004,39(1):185-198
The purpose of this research was to neutralize livestock-generated ammonia by using biofilters packed with inexpensive inorganic and organic packing material combined with multicultural microbial load at typical ambient temperatures. Peat and inorganic supporting materials were used as biofiltration matrix packed in a perfusion column through which gas was transfused. Results show the ammonia removal significantly fell in between 99 and 100% when ammonia concentration of 200 ppmv was used at different gas flow rates ranged from 0.030 to 0.060 m3 h(-1) at a fluctuating room temperature of 27.5 +/- 4.5 C (Mean +/- SD). Under these conditions, the emission concentration of ammonia that is liberated after biofiltration is less than 1 ppmv (0.707 mg m(-3)) over the period of our study, suggesting the usage of low-cost biofiltration systems for long-term function is effective at wider ranges of temperature fluctuations. The maximum (100%) ammonia removal efficiency was obtained in this biofilter was having an elimination capacity of 2.217 g m(-3) h(-1). This biofilter had high nitrification efficiencies and hence controlled ammonia levels with the reduced backpressure. The response of this biofilter to shut down and start up operation showed that the biofilm has a superior stability. 相似文献
967.
Biological responses of workplace particles and their association with adverse health effects on miners 总被引:2,自引:0,他引:2
Chen W Stempelmann K Rehn S Diederichs H Rehn B Bruch J 《Journal of environmental monitoring : JEM》2004,6(12):967-972
Epidemiological research has demonstrated the relationship between exposure to quartz dust and an elevated risk of pneumoconiosis and possible elevated risk of cancer. The current study was designed to evaluate the biological responses of workplace particles containing crystalline silica using an in vitro cell test. Respirable particle samples were sampled from four tin mines, where the standardized mortality ratio (SMR) for pneumoconiosis was 51.6 and SMR for lung cancer was 2.2 in dust-exposed miners. Alveolar macrophages (AM) are considered as the target cells for primary dust effects. The samples were then measured at 15, 30, 60 and 120 microg particle per 10(6) AM for cytoxicity with the release of glucuronidase, lactate dehydrogenase, for reactive oxygen damage with H(2)O(2) release, and for ability to induce fibrosis using the secretion of tumor necrosis factor-alpha (TNF-alpha). Pure quartz (DQ12) and corundum were used as controls. The results showed the samples from tin mines caused a higher cytoxicity when compared to corundum, yet lower when compared to quartz. However, reactive oxygen species release (148-177 nmol/3 x 10(5) AM in high concentration of 120 microg/10(6) AM) induced by the samples were significantly higher than that induced by quartz (57 nmol/3 x 10(5) AM) and corundum (62 nmol/3 x 10(5) AM). Furthermore, particle samples induced higher TNF-alpha secretion than corundum, the samples from Limu tin mine induced much higher TNF-alpha levels than that induced by DQ12 quartz. The results from the in vitro tests help elucidate the degree of hazard of dust particles in tin mines. The in vitro reaction patterns of AM also constitute a powerful tool to monitor biological and pathogenic responses of humans following dust particle exposure. 相似文献
968.
Quang NH Long NQ Lieu DB Mai TT Ha NT Nhan DD Hien PD 《Journal of environmental radioactivity》2004,75(3):329-337
Fallout 239+240Pu, 238Pu, 90Sr and 137Cs inventories in surface soils were measured for 20 locations in northern Vietnam yielding the mean values (+/- standard error) of 26.5+/-3.8 Bq m(-2) for 239+240Pu, 1048+/-143 Bq m(-2) for 137Cs and 212+/-28 Bq m(-2) for 90Sr. The concentrations of 137Cs and plutonium isotopes strongly correlate with each other resulting in a stable 239+240Pu/137Cs inventory ratio of 0.025+/-0.002. Among soil parameters, organic matter and fulvic acids strongly correlate with caesium and plutonium isotopes, especially in the 0-10 cm layer. 137Cs and 239+240Pu are distributed rather similarly over the 0-10 cm and 10-20 cm layers. At locations with high contents of sand (82-93%) along the South China Sea coast, the downward percolation by rainwater results in a higher accumulation of 239+240Pu and 137Cs in the 10-20 cm layer. The mean 137Cs/ 90Sr inventory ratio is 9.3+/-2.2, and the correlation is weak between these isotopes. 相似文献
969.
Integrated effects of applied pressure,time, and polymer doses on alum sludge dewatering behaviour 总被引:2,自引:0,他引:2
In this study, combinations of applied pressure, pressing time and polymer dose were examined in an air pressure plate apparatus to explore their integrated influence on the dewatering of an alum sludge. Results of the investigation demonstrated that dewatering can be enhanced by increases in pressure and time. However, a point is reached at which continued increases in pressure and time offer little benefit. The data also confirmed that polymer affects the rate of water release rather than the extent of dewatering. Increased rates of water release due to increasing polymer dose can be attributed to the aggregation of sludge particles by polymer addition. It was also evident in this study that the initial sludge depth has a major impact on the average cake moisture content at a given dewatering time. It was apparent that once the initial sludge thickness exceeds about 2 cm, the water release follows a fairly similar pattern, which can be represented by a simple empirical model. 相似文献
970.
Chen Guojie 《中国减灾(英文版)》2002,(3)
Bytheendofthe 2 0thcentury ,themajorityofmountainregionsinChina ,especiallythosepoverty strickenareas,hadsolvedtheproblemsoffoodandclothing .Theyarenowmarchingtowardthegoaloflivingawell offlife .Newchallengesthatthemountainregionsarefacedwithinthe 2 1stcentur… 相似文献