全文获取类型
收费全文 | 22043篇 |
免费 | 79篇 |
国内免费 | 84篇 |
专业分类
安全科学 | 283篇 |
废物处理 | 1318篇 |
环保管理 | 2726篇 |
综合类 | 3436篇 |
基础理论 | 5993篇 |
环境理论 | 5篇 |
污染及防治 | 4668篇 |
评价与监测 | 1722篇 |
社会与环境 | 2000篇 |
灾害及防治 | 55篇 |
出版年
2022年 | 91篇 |
2021年 | 98篇 |
2019年 | 70篇 |
2018年 | 1698篇 |
2017年 | 1591篇 |
2016年 | 1445篇 |
2015年 | 296篇 |
2014年 | 254篇 |
2013年 | 825篇 |
2012年 | 788篇 |
2011年 | 1857篇 |
2010年 | 1152篇 |
2009年 | 1073篇 |
2008年 | 1443篇 |
2007年 | 1871篇 |
2006年 | 431篇 |
2005年 | 443篇 |
2004年 | 411篇 |
2003年 | 509篇 |
2002年 | 510篇 |
2001年 | 446篇 |
2000年 | 327篇 |
1999年 | 212篇 |
1998年 | 140篇 |
1997年 | 123篇 |
1996年 | 108篇 |
1995年 | 154篇 |
1994年 | 148篇 |
1993年 | 123篇 |
1992年 | 130篇 |
1991年 | 149篇 |
1990年 | 119篇 |
1989年 | 127篇 |
1988年 | 132篇 |
1987年 | 114篇 |
1986年 | 83篇 |
1985年 | 99篇 |
1984年 | 141篇 |
1983年 | 134篇 |
1982年 | 123篇 |
1981年 | 97篇 |
1980年 | 93篇 |
1979年 | 106篇 |
1978年 | 89篇 |
1977年 | 84篇 |
1976年 | 78篇 |
1975年 | 90篇 |
1974年 | 101篇 |
1972年 | 69篇 |
1965年 | 74篇 |
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
131.
132.
Recent drinking water regulations have lowered the disinfection by-product standards as well as added new disinfection by-products for regulation. Natural organic matter (NOM) plays a major role in the formation of undesirable organic by-products following disinfection/oxidation of drinking water. It is suspected that most precursors to disinfection by-products are humic, although nonhumic substances are also suspected of contributing to these by-products. Many of the disinfection by-products have adverse health effects in humans (i.e., carcinogenic or mutagenic effects). The primary chlorinated disinfection by-products of concern include trihalomethanes, haloacetic acids, and haloacetonitrile. Fluorescence spectroscopy was used to study humic and fulvic acids. The two fractions of humic substances, humic and fulvic acids, were characterized by a double-peak phenomena in an overlapping fluorescing region. Disinfection by-product formation potentials of humic and fulvic acids have been correlated with total organic carbon, UV absorbance at 254 nm, specific absorbance and fluorescence. River humic and fulvic acid was found to have the highest reactivity to disinfection by-product formation as compared to soil and peat humic and fulvic acid. Fluorescence spectroscopy has shown to be a rapid and predictive tool for disinfection by-products formation potential of humic and fulvic acids. 相似文献
133.
E. Lamla F. Boschke G. Traving G. Pfotzer H. Wolter W. Walcher H. D. Dahmen H. J. Queisser W. W. Klingbeil K. Beyermann O. Müller R. R. Ernst D. Reinen H. Muth W. Becker G. Wunsch G. I. Distler L. Jaenicke H. G. v. Schnering H. Werner F. Reiff H. Schimassek W. Höll H. K. Vasil W. F. Angermeier W. Ruppel J. C. Eccles G. Spiteller H. Oettel W. Vogell P. Brosche K. J. Hsü H. -U. Schmincke 《Die Naturwissenschaften》1975,62(3):143-143
134.
135.
136.
Chorionic villus sampling: Improved method for preparation of karyotypes after short-term incubation
A method for the isolation and trypsin-Giemsa banding of metaphases obtained after short-term incubation (48 h) of cytotrophoblast cells from chorionic villus sample is described. A new slide-making instrument, developed expressly to enhance the spreading of chromosomes from metaphases released from small tissue pieces, is responsible for the increase yield of analysable metaphases in this protocol. 相似文献
137.
138.
Gulzar Kassam Andrew T. L. Chen Marshall F. Goldberg Suzanne Trusler Godfrey P. Oakley Jr. 《黑龙江环境通报》1984,4(3):213-216
Although prenatal genetic diagnosis can usually provide prospective parents with information as to whether their fetus is affected with certain genetic conditions, the presence of twins and the uncertainty about the phenotype of some chromosome variations pose a major dilemma and make genetic counselling very difficult. Here, a case report of an unusual chromosome aberration (pericentric inversion of chromosome no. 17) in a twin pregnancy which was originally suspected to be monoamniotic but later proved to have two sacs was presented. 相似文献
139.
140.