全文获取类型
收费全文 | 30718篇 |
免费 | 475篇 |
国内免费 | 1135篇 |
专业分类
安全科学 | 993篇 |
废物处理 | 1376篇 |
环保管理 | 3909篇 |
综合类 | 5869篇 |
基础理论 | 8336篇 |
环境理论 | 12篇 |
污染及防治 | 8067篇 |
评价与监测 | 1963篇 |
社会与环境 | 1536篇 |
灾害及防治 | 267篇 |
出版年
2022年 | 352篇 |
2021年 | 344篇 |
2020年 | 281篇 |
2019年 | 291篇 |
2018年 | 476篇 |
2017年 | 501篇 |
2016年 | 685篇 |
2015年 | 590篇 |
2014年 | 848篇 |
2013年 | 2405篇 |
2012年 | 1031篇 |
2011年 | 1367篇 |
2010年 | 1112篇 |
2009年 | 1116篇 |
2008年 | 1374篇 |
2007年 | 1368篇 |
2006年 | 1250篇 |
2005年 | 1023篇 |
2004年 | 958篇 |
2003年 | 1011篇 |
2002年 | 944篇 |
2001年 | 1226篇 |
2000年 | 882篇 |
1999年 | 532篇 |
1998年 | 408篇 |
1997年 | 419篇 |
1996年 | 444篇 |
1995年 | 500篇 |
1994年 | 435篇 |
1993年 | 373篇 |
1992年 | 390篇 |
1991年 | 381篇 |
1990年 | 400篇 |
1989年 | 377篇 |
1988年 | 332篇 |
1987年 | 312篇 |
1986年 | 272篇 |
1985年 | 281篇 |
1984年 | 324篇 |
1983年 | 282篇 |
1982年 | 337篇 |
1981年 | 278篇 |
1980年 | 233篇 |
1979年 | 257篇 |
1978年 | 218篇 |
1977年 | 190篇 |
1975年 | 187篇 |
1974年 | 200篇 |
1973年 | 197篇 |
1972年 | 180篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
591.
Consanguineous partners had a boy with campomelic dysplasia who died of increasing respiratory distress soon after birth. The next pregnancy was monitored frequently by ultrasonography and a healthy male infant was born at term. During a further pregnancy, ultrasonography suggested campomelic dysplasia in the 16th week of gestation. This was confirmed in the 18th week. The pregnancy was terminated and the fetus showed the typical radiological, anatomical and histological findings. 相似文献
592.
J. G. Hooker M. Lucas B. A. Richards I. M. Shirley B. D. Thompson R. H. T. Ward 《黑龙江环境通报》1984,4(1):29-33
Estimation of maternal serum alpha-fetoprotein (AFP) was used as a screening method for the detection of neural tube defects (NTDs) in 6344 women over three years. Of 88 (1.4 per cent) who had one or more serum AFP levels equal to, or greater than, 2.5 multiples of the median (MoM) for the relevant gestational age, 43 (0.68 per cent) underwent amniocentesis. There were eight NTDs. Four of these were screened by serum AFP, and all cases of spina bifida had serum AFP levels greater than 3.0 MoM, including one small open defect which was not seen on ultrasound. The other four cases of NTD, which were not screened, were identified by ultrasound. Of 64 singleton pregnancies 32 (50 per cent) had serum AFP levels between 2.5 and 3.0 MoM, and low birthweight (⪕2500 g) occurred in 29 per cent. Because of improvements in ultrasound techniques and the apparent falling incidence of NTD, the role of serum AFP as the primary screening procedure should be regularly reviewed. Effective screening is dependent on mothers booking early. 相似文献
593.
True microcephaly can be diagnosed at an early stage of gestation by serial measurements of fetal head growth as demonstrated by this case report in which the diagnosis of genetic microcephaly was made but termination refused. True microcephaly was evident at birth. 相似文献
594.
595.
596.
597.
598.
599.
洛阳分公司恶臭污染调查及防治 总被引:2,自引:0,他引:2
程俊梅 《石油化工环境保护》2005,28(1):31-33,i002
分析了洛阳分公司恶臭污染源,提出了解决恶臭污染的常用方法及对洛阳分公司恶臭污染源的控制及治理途径。 相似文献
600.
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