全文获取类型
收费全文 | 19087篇 |
免费 | 597篇 |
国内免费 | 2199篇 |
专业分类
安全科学 | 860篇 |
废物处理 | 791篇 |
环保管理 | 2217篇 |
综合类 | 6060篇 |
基础理论 | 4361篇 |
环境理论 | 9篇 |
污染及防治 | 4911篇 |
评价与监测 | 1182篇 |
社会与环境 | 1207篇 |
灾害及防治 | 285篇 |
出版年
2023年 | 228篇 |
2022年 | 527篇 |
2021年 | 476篇 |
2020年 | 447篇 |
2019年 | 403篇 |
2018年 | 498篇 |
2017年 | 520篇 |
2016年 | 621篇 |
2015年 | 643篇 |
2014年 | 758篇 |
2013年 | 1541篇 |
2012年 | 884篇 |
2011年 | 1034篇 |
2010年 | 848篇 |
2009年 | 912篇 |
2008年 | 993篇 |
2007年 | 861篇 |
2006年 | 809篇 |
2005年 | 662篇 |
2004年 | 598篇 |
2003年 | 620篇 |
2002年 | 568篇 |
2001年 | 704篇 |
2000年 | 549篇 |
1999年 | 336篇 |
1998年 | 252篇 |
1997年 | 248篇 |
1996年 | 241篇 |
1995年 | 253篇 |
1994年 | 246篇 |
1993年 | 211篇 |
1992年 | 182篇 |
1991年 | 197篇 |
1990年 | 190篇 |
1989年 | 175篇 |
1988年 | 134篇 |
1987年 | 120篇 |
1986年 | 130篇 |
1985年 | 100篇 |
1984年 | 122篇 |
1983年 | 119篇 |
1982年 | 131篇 |
1981年 | 115篇 |
1980年 | 101篇 |
1979年 | 117篇 |
1978年 | 80篇 |
1977年 | 78篇 |
1975年 | 84篇 |
1973年 | 80篇 |
1972年 | 80篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
881.
J. Altenburger Th. Dielacher P. Eder H. Ferner M. Fegerl J. Fresner O. Gelinek A. Kogler J. Jantschgi M. Nussbaumer B. Russegger H. Schnitzer K. Schauer B. Sebesta J. Seiler F. Sprenger H. Widenmeyer 《Journal of Cleaner Production》1994,2(3-4)
The paper focuses upon the organization of a federal state-funded pollution prevention project in the Styrian industry. The project includes 13 companies from the textile, pulp and paper, machine building, wood working and printed circuit board manufacturing industries, covering most of the sectors and sizes in the Styrian industry. It started in January 1994 and will last for one year. It will demonstrate the possibilities of pollution prevention and the need for further research work. This project will make use of the methods and tools that were refined in the Austrian Prepare project. As a first step, a systematic balance of all the inputs and outputs of a company is made, after which the weak points and inefficiencies of material and energy use are identified and the options for improvements, both economical and ecological, are defined. Consequently, modifications in products and production lead to a situation with less waste and emissions. The preliminary lessons from these projects are presented: as a rule, the utilities (consumption of process materials and water, cleaning, energy, preparatory and finishing steps) are treated as black boxes and usually represent a considerable optimization potential. In these areas especially there is usually a lack of information and coordination as well as a need for a systematic and comprehensive approach. Leadership in the company and creative consultants are needed for starting lasting successful pollution prevention projects. 相似文献
882.
883.
884.
885.
886.
R. G. Tiessen A. M. W. van Elsacker-Niele Chr. Vermeij-Keers D. Oepkes J. van Roosmalen M. C. B. Gorsira 《黑龙江环境通报》1994,14(3):173-176
A fetus with multiple structural defects was seen at prenatal ultrasound examination. After termination of the pregnancy a bilateral cleft lip, alveolus, and palate; micrognathia; and webbed joints were seen. Fetal tissues showed indications of infection, intranuclear inclusion bodies, chronic stress, haemolysis, arterial wall damage, and profuse haemorrhage. Parvovirus B19 DNA was detected in fetal tissues by dot hybridization after polymerase chain reaction. The possibility of parvovirus B19 infection leading to congenital malformations is discussed. 相似文献
887.
Foci of calcification were observed at autopsy in the liver of a fetus with complete trisomy 9 on which two cordocenteses had been performed. It is suggested that liver calcifications are a possible complication of the procedure. As several other cases of calcifications in the liver and other organs of fetuses with autosomal trisomies have been described without a history of cordocentesis, further studies should be carried out to determine whether fetuses with chromosomal anomalies are more prone to thrombus formation and embolization. 相似文献
888.
We report our cytogenetic experience of 1554 early amniocenteses between weeks 11 and 14 of gestation, of which 44 per cent were performed prior to week 14. The mean culture time was 14·5 days. Karyotyping was successful in 99·7 per cent of cases. In 9·9 per cent of cases, there was pseudomosaicism with a high rate of loss of an X-chromosome and structural aberration of chromosome 1, which may be due to the Chang medium. The mosaic rate was 0·5 per cent. The overall aberration rate was 2·8 per cent. Our data confirm the reliability of early amniocentesis, which is a serious alternative to standard amniocentesis and chorionic villus sampling (CVS). 相似文献
889.
J. M. Martinez A. Fortuny C. Comas B. Puerto A. Borrell M. Palacio O. Coll 《黑龙江环境通报》1994,14(8):669-672
A case of body stalk anomaly diagnosed prenatally by ultrasound during the 24th week of pregnancy in a cocaine abusing mother is presented. Accurate visualization of the fetal organs was difficult due to the severe oligohydramnios caused by premature rupture of membranes, probably related to the cocaine use. The sonographic findings were an omphalocoele, fetal attachment to the placenta, kyphoscoliosis, and absence of a floating umbilical cord. The prenatal diagnosis of the syndrome and the possible relationship with cocaine abuse are discussed. 相似文献
890.
Maternal serum alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (βhCG) measurements taken prior to chorionic villus sampling (CVS) in 21 patients who subsequently miscarried were compared with measurements in a control group of 113 patients with uneventful pregnancies. Patients with AFP levels of 10 iu/ml or more prior to the CVS had a 4·3 times greater risk of miscarriage (95 per cent confidence interval 1·3–13·6). AFP levels obtained 1 week after the CVS in the 13 patients with late miscarriages were higher than in the control group (P = 0·06). Patients miscarrying had a greater rise in AFP (P = 0·06) and a greater fall in βhCG levels (P = 0·04) following the CVS procedure, compared with the control subjects. Each 10-unit change in the difference between AFP or βhCG levels prior to and 1 week following the CVS was associated with a significantly increased risk for late miscarriage. Elevated maternal serum AFP levels early in pregnancy and changes in AFP and βhCG levels following CVS may predict an increased risk for subsequent miscarriage. 相似文献