全文获取类型
收费全文 | 1637篇 |
免费 | 6篇 |
国内免费 | 42篇 |
专业分类
安全科学 | 45篇 |
废物处理 | 105篇 |
环保管理 | 150篇 |
综合类 | 245篇 |
基础理论 | 345篇 |
环境理论 | 1篇 |
污染及防治 | 524篇 |
评价与监测 | 117篇 |
社会与环境 | 147篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 13篇 |
2022年 | 46篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 15篇 |
2018年 | 55篇 |
2017年 | 22篇 |
2016年 | 29篇 |
2015年 | 49篇 |
2014年 | 38篇 |
2013年 | 119篇 |
2012年 | 62篇 |
2011年 | 89篇 |
2010年 | 65篇 |
2009年 | 80篇 |
2008年 | 96篇 |
2007年 | 99篇 |
2006年 | 66篇 |
2005年 | 58篇 |
2004年 | 92篇 |
2003年 | 72篇 |
2002年 | 51篇 |
2001年 | 106篇 |
2000年 | 45篇 |
1999年 | 25篇 |
1998年 | 16篇 |
1997年 | 12篇 |
1996年 | 10篇 |
1995年 | 21篇 |
1994年 | 7篇 |
1993年 | 9篇 |
1992年 | 15篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 10篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1985年 | 8篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1980年 | 6篇 |
1975年 | 8篇 |
1974年 | 10篇 |
1973年 | 7篇 |
1972年 | 12篇 |
1971年 | 5篇 |
1966年 | 5篇 |
1965年 | 5篇 |
1959年 | 5篇 |
1957年 | 5篇 |
排序方式: 共有1685条查询结果,搜索用时 31 毫秒
21.
The nature of the cosmic redshift is one of the most fundamental questions in modern science. Hubble's discovery of the apparent Expansion of the Universe is derived from observations on a small number of galaxies at very low redshifts. Today, quasar redshifts have a range more than 1000 times greater than those in Hubble's sample, and represent more than 100 times as many objects. A recent comprehensive compilation of published measurements provides the basis for a study indicating that quasar observations are not in good agreement with the original predictions of the Expanding Universe theory, but are well fit by the predictions of an alternative theory having fewer adjustable parameters. 相似文献
22.
23.
24.
25.
26.
Urinary tract anomalies are common. Prenatal diagnosis is important and enables either special obstetric management or termination of pregnancy and probably in the future, intrauterine intervention. Transvaginal sonography (TVS) allows visualization of the normal and anomalous fetal urinary tract at an early stage. One thousand nine hundred and forty women were examined via TVS at an early stage of pregnancy between 10 and 16 weeks from the last menstrual period (LMP) and 35 anomalies (1·8 per cent) were clearly identified: 29 cases of low urinary tract obstruction, 2 cases of multicystic dysplastic kidney, 2 cases of polycystic kidney (infantile type), 1 case of double collecting system, and 1 case of horseshoe kidney. Potter syndrome could be ruled out in three patients who had delivered fetuses suffering from this anomaly in previous pregnancies. The concise and early identification of anomalies makes TVS an important aid in the hands of the obstetrician, ultrasonographer, and neonatologist. 相似文献
27.
ZHANG Tian-zhu 《环境科学学报(英文版)》2001,13(3):346-350
IntroductionCleanerproduction (CP)holdsgreatpromiseasaneffectivestrategyinthefaceofdoublechallengesofenvironmentalprotectionandeconomicdevelopment.In 1993,ademonstrationproject (B 4project) ,designedandexecutedbytheStateEnvironmentalProtectionAdministration (… 相似文献
28.
The discussion on the possible increase of solar UV on earth due to the destruction of the stratospheric ozone has led to a renewed interest in the action of ultraviolet radiation on biological systems. The paper deals with changes at the cellular level stressing particularly molecular alterations in deoxyribonucleic acid, the carrier of genetic information. The most important repair processes by which lesions are removed or bypassed are described. It is also discussed whether the effectivity of a complex spectrum can be predicted on the basis of measurements with monochromatic radiation. Furthermore, possible consequences on human health are outlined which may be derived from cellular studies. 相似文献
29.
Grant R. Sutherland Elizabeth Baker Stuart Purvis-Smith Athel Hockey Ed Krumins Sam Z. Eichenbaum 《黑龙江环境通报》1987,7(3):197-202
Eleven pregnancies in ten patients at risk for the fragile X were monitored by amniocentesis or chorion villus biopsy and induction of the fragile site using thymidine, methotrexate and FUdR. Three female fetuses and one male fetus were found to have the fragile X. The results obtained using thymidine induction were superior to those using methotrexate induction and probably better than those obtained using FUdR induction. 相似文献
30.