全文获取类型
收费全文 | 4006篇 |
免费 | 33篇 |
国内免费 | 11篇 |
专业分类
安全科学 | 43篇 |
废物处理 | 265篇 |
环保管理 | 244篇 |
综合类 | 636篇 |
基础理论 | 818篇 |
环境理论 | 4篇 |
污染及防治 | 1418篇 |
评价与监测 | 374篇 |
社会与环境 | 240篇 |
灾害及防治 | 8篇 |
出版年
2023年 | 44篇 |
2022年 | 125篇 |
2021年 | 120篇 |
2020年 | 46篇 |
2019年 | 50篇 |
2018年 | 147篇 |
2017年 | 105篇 |
2016年 | 203篇 |
2015年 | 109篇 |
2014年 | 228篇 |
2013年 | 387篇 |
2012年 | 245篇 |
2011年 | 240篇 |
2010年 | 186篇 |
2009年 | 140篇 |
2008年 | 229篇 |
2007年 | 230篇 |
2006年 | 210篇 |
2005年 | 145篇 |
2004年 | 120篇 |
2003年 | 106篇 |
2002年 | 92篇 |
2001年 | 60篇 |
2000年 | 44篇 |
1999年 | 34篇 |
1998年 | 14篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1995年 | 23篇 |
1994年 | 16篇 |
1993年 | 12篇 |
1992年 | 7篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1985年 | 6篇 |
1970年 | 6篇 |
1967年 | 7篇 |
1966年 | 11篇 |
1965年 | 15篇 |
1964年 | 28篇 |
1963年 | 12篇 |
1962年 | 17篇 |
1961年 | 11篇 |
1960年 | 9篇 |
1959年 | 26篇 |
1958年 | 25篇 |
1957年 | 17篇 |
1956年 | 13篇 |
1955年 | 18篇 |
1954年 | 7篇 |
排序方式: 共有4050条查询结果,搜索用时 15 毫秒
951.
Mária Szabó Ákos Münnich Farkas Teichmann Mariann Huszka Lajos Veress Professor Zoltán Papp 《黑龙江环境通报》1990,10(12):761-769
We have analysed the sensitivity, specificity, and reliability of biochemical diagnosis based on microvillar membrane enzyme assay and using discriminant analysis in amniotic fluid samples obtained from 54 pregnancies at high risk for cystic fibrosis and 125 normal pregnancies. Our results show that amniotic fluid trehalase, alkaline phosphatase, alkaline phosphatase isoenzymes and gamma-glutamyltransferase enzyme activities measured during 16–20 gestational weeks, in spite of their non-specificity for cystic fibrosis, have a very good predictive value for fetal cystic fibrosis or exclude the possibility of the disease. Overall enzyme activity analysis provided over 90 per cent reliability of the method. 相似文献
952.
953.
954.
Apesteguía S 《Die Naturwissenschaften》2004,91(10):493-497
Ornithischian and theropod dinosaurs were morphologically diverse during the Cretaceous. In contrast, sauropods were relatively more conservative. The anatomy of Bonitasaura salgadoi, a new 9-m titanosaurian sauropod from Upper Cretaceous beds of Patagonia, suggests that sauropod anatomical diversity would have included unexpected items. Its unusual, rectangular lower jaw possesses narrow, anteriorly restricted teeth and shows evidence of a sharp keratinous sheath over the non-dentigerous region that probably worked to guillotine plant material. This discovery definitely demonstrates that titanosaurs acquired a mandibular configuration similar to that of some basal diplodocoids, as had already been suggested by the lower jaw of the controversial genus Antarctosaurus. This oral configuration, plus the beak-like structure and the skull shape, resemble some traits more commonly seen in Laurasian ornithischians, mostly unexpressed in southern continents. A high sauropod morphological diversity seems to be in agreement with the poorly represented ornithischian clades of the southern hemisphere.Communicated by G. Mayr 相似文献
955.
Unai?IriarteEmail author Jon?I?aki?álvarez-Uriarte Rubén?López-Fonseca Juan?Ramón?González-Velasco 《Environmental Chemistry Letters》2003,1(1):57-61
The relatively recent discovery of disinfection by-products has driven the main regulatory organisms to set maximum contaminant
levels for certain substances in drinking water. Trihalomethanes can be deemed as the most important group of by-products
in chlorinated surface waters. The present work has focused on trihalomethane formation in a full-scale water treatment plant.
We studied the effect of several factors, including ozonation, on trihalomethane levels in chlorinated treated water. The
treatment scheme also includes an ozonation step.
Electronic Publication 相似文献
956.
957.
958.
959.
960.