全文获取类型
收费全文 | 38290篇 |
免费 | 4636篇 |
国内免费 | 26635篇 |
专业分类
安全科学 | 1950篇 |
废物处理 | 1642篇 |
环保管理 | 4792篇 |
综合类 | 33028篇 |
基础理论 | 9788篇 |
环境理论 | 10篇 |
污染及防治 | 12375篇 |
评价与监测 | 3464篇 |
社会与环境 | 2099篇 |
灾害及防治 | 413篇 |
出版年
2023年 | 146篇 |
2022年 | 273篇 |
2021年 | 337篇 |
2020年 | 788篇 |
2019年 | 2095篇 |
2018年 | 2448篇 |
2017年 | 2452篇 |
2016年 | 2468篇 |
2015年 | 2707篇 |
2014年 | 3678篇 |
2013年 | 5470篇 |
2012年 | 3866篇 |
2011年 | 3688篇 |
2010年 | 3277篇 |
2009年 | 3289篇 |
2008年 | 3181篇 |
2007年 | 3139篇 |
2006年 | 2506篇 |
2005年 | 2055篇 |
2004年 | 1903篇 |
2003年 | 1672篇 |
2002年 | 1484篇 |
2001年 | 1654篇 |
2000年 | 1419篇 |
1999年 | 1051篇 |
1998年 | 803篇 |
1997年 | 809篇 |
1996年 | 844篇 |
1995年 | 869篇 |
1994年 | 656篇 |
1993年 | 541篇 |
1992年 | 645篇 |
1991年 | 614篇 |
1990年 | 560篇 |
1989年 | 521篇 |
1988年 | 438篇 |
1987年 | 318篇 |
1986年 | 324篇 |
1985年 | 302篇 |
1984年 | 325篇 |
1983年 | 303篇 |
1982年 | 319篇 |
1981年 | 267篇 |
1980年 | 170篇 |
1979年 | 186篇 |
1978年 | 167篇 |
1977年 | 140篇 |
1975年 | 139篇 |
1973年 | 170篇 |
1972年 | 149篇 |
排序方式: 共有10000条查询结果,搜索用时 947 毫秒
321.
盐酸付玫瑰苯胺是三苯甲烷类染料,分子中存在的共轭体系使其具有以下特性:1.本身带色;2.随介质的pH变化产生显著的颜色效应,pH值越高,颜色越深,pH值越低,颜色越浅;3.对光和水洗的坚牢度较差;4.可发生重氮化反应;5.杂质使其颜色加深。 相似文献
322.
对绵阳市的环境放射源基本情况进行了分析,弄清了放射源的品种、数量。摸索出放射性核素及X射线装置在地域、行业和剂量方面的分布规律,揭示出环境放射性管理工作的重点。 相似文献
323.
Alexandra E. Boekhold Sjoerd E. A. T. M. Van Der Zee 《Environmental monitoring and assessment》1994,29(1):1-15
CaCl2-extractable soil Cd and Zn contents have been suggested as a measure of bioavailability. To investigate the ability of this measure to reflect spatial patterns of Cd and Zn concentrations in barley (Hordeum vulgare L.) in an arable field, plant and soil samples were taken from a 0.5 ha area sandy soil contaminated with Cd and Zn. Cd and Zn contents in barley and yield were spatially variable. Yield was low, which may have been caused by Zn toxicity or atrazine turnover. For Cd, CaCl2-extractable soil contents explained only 17% of the variation in Cd contents in grain, and for Zn no significant correlation was observed. Nevertheless, surface plots of CaCl2-extractable soil contents and contents of barley grain illustrated their corresponding spatial patterns. Despite the poor linear correlation between CaCl2-extractable soil-Cd and grain-Cd, a stochastic model for long term behaviour of Cd in field soils predicted observed variability in Cd contents of barley grain well from spatial variability of soil pH and organic matter content. The probabilistic model predicted behaviour of Cd in terms of probability, and was more appropriate than the deterministic approach. 相似文献
324.
Static bioassays were carried out using two aquatic snails (Pilia sp. and Lanistes sp.) as test organisms in soft natural dilution water, with waste drilling fluid as the test material, at 28±2°C. Comparison of results for the control and different concentrations of the waste drilling fluid were made by means of the F-statistic method. The waste drilling fluid was practically non-toxic to the two aquatic snails. 相似文献
325.
326.
327.
通过对大气细菌数量、霉菌数量与风速相关性的研究,得出齐市地区冬季气候寒冷,无相关性;春季气候干燥,风沙大,有相关性;雨后大气细菌数量与风速无相关性,大气霉菌数量与风速相关。 相似文献
328.
为了筛选蚕豆叶尖微核监测技术敏感材料,以二甲苯为污染物,对甘肃产的10个蚕豆品种进行了测试。结果表明,蚕引8号微核出现率与二甲苯诱变剂浓度成正比,平均微核率差异极显著,是监测评价二甲苯污染的敏感品种。 相似文献
329.
Physical and chemical (nutrients and major ions) indicators of water quality monitored by Environment Canada between 1977 and 1987 in the Niagara River at Niagara-on-the-Lake and in the St. Lawrence River at Wolfe Island are analyzed for seasonal and annual variations. Parametric methods such as moving averages and linear regression and nonparametric methods (Spearman's rank coefficient) are used to test for the existence of trends in these data. The results indicate that specific conductivity, sodium and chloride have decreased significantly over the period of study. During the same period there is no significant trend for either discharge and nutrients. 相似文献
330.
Ports can generate large quantity of pollutants in the atmosphere due to various activities like loading and unloading,transportation, and construction operations. Determination of the character and quantity of emissions from individual sources is an essential step in any project to control and minimize the emissions.In this study a detailed emission inventory of total suspendedparticulate matter (TSP), particulate matter less than 10 m(PM10), sulfur dioxide (SO2) and nitrogen oxides (NOx) for a port and harbour project near Mumbai is compiled. Results show that the total annual average contributions of TSP and PM10 from all the port activitieswere 872 and 221 t yr-1, respectively. Annual average emissions of gaseous pollutants SO2 and NOxwere 56 and 397 t yr-1, respectively, calculatedby using emission factors for different port activities. The maximum TSP emission (419 t yr -1) was from paved roads, while the least (0.4 t yr-1) was from bulk handling activity. The maximum PM10 emission (123 t yr-1) was from unpaved roads and minimum (0.2 t yr-1) from bulk handling operations. Similarly the ratio of TSP and PM10 emission was highest (5.18) from paved roads and least (2.17) from bulk handling operations. Regression relation was derivedfrom existing emission data of TSP and PM10 from variousport activities. Good correlation was observed between TSP andPM10 having regression coefficient >0.8. 相似文献