全文获取类型
收费全文 | 18106篇 |
免费 | 143篇 |
国内免费 | 112篇 |
专业分类
安全科学 | 424篇 |
废物处理 | 653篇 |
环保管理 | 1978篇 |
综合类 | 6015篇 |
基础理论 | 3614篇 |
环境理论 | 2篇 |
污染及防治 | 4114篇 |
评价与监测 | 882篇 |
社会与环境 | 616篇 |
灾害及防治 | 63篇 |
出版年
2018年 | 200篇 |
2017年 | 188篇 |
2016年 | 287篇 |
2015年 | 219篇 |
2014年 | 319篇 |
2013年 | 1185篇 |
2012年 | 370篇 |
2011年 | 517篇 |
2010年 | 498篇 |
2009年 | 558篇 |
2008年 | 578篇 |
2007年 | 600篇 |
2006年 | 526篇 |
2005年 | 467篇 |
2004年 | 504篇 |
2003年 | 468篇 |
2002年 | 443篇 |
2001年 | 617篇 |
2000年 | 412篇 |
1999年 | 283篇 |
1998年 | 214篇 |
1997年 | 199篇 |
1996年 | 194篇 |
1995年 | 280篇 |
1994年 | 283篇 |
1993年 | 243篇 |
1992年 | 247篇 |
1991年 | 252篇 |
1990年 | 281篇 |
1989年 | 245篇 |
1988年 | 209篇 |
1987年 | 202篇 |
1986年 | 195篇 |
1985年 | 189篇 |
1984年 | 210篇 |
1983年 | 198篇 |
1982年 | 203篇 |
1981年 | 210篇 |
1980年 | 170篇 |
1979年 | 185篇 |
1978年 | 147篇 |
1976年 | 144篇 |
1974年 | 151篇 |
1973年 | 155篇 |
1968年 | 156篇 |
1967年 | 184篇 |
1966年 | 154篇 |
1965年 | 148篇 |
1964年 | 151篇 |
1963年 | 141篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
321.
322.
323.
324.
Dr M. Buscaglia L. Ghisoni M. Bellotti A. M. Marconi P. Zamperini L. Stripparo A. Molinari M. G. Grimoldi F. Rossella 《黑龙江环境通报》1995,15(1):17-19
We present a technique to aspirate amniotic fluid from both sacs in biamniotic twin pregnancies using a single abdominal insertion with a spinal needle. It was successful in 48 out of 55 cases of biamniotic twin pregnancies referred to our perinatal unit between 1985 and 1994. The single insertion technique was used when the inter-amniotic membrane was clearly evident and two separate free amniotic fluid pools could be reached by the operator with a single puncture. An adequate amount of amniotic fluid was sampled from both sacs to make a cytogenetic diagnosis in all cases. There were four fetuses with trisomy 21 in three twin pregnancies. In two cases, only one twin was affected whilst the co-twin was normal, so that a selective feticide was performed. No miscarriages due to genetic amniocentesis were reported. After 1990, all genetic amniocenteses in biamniotic twin pregnancies (except for one case due to late booking) were performed between 14 and 15 weeks of gestation and with all cases except one, it was possible to sample both twins by a single puncture. We suggest that early amniocentesis (14–15 weeks) by a single abdominal puncture could be a reliable and safe alternative to first-trimester chorionic villus sampling in twin pregnancies. 相似文献
325.
326.
IntroductionTheprocessofmunicipalsolidwaste(MSW)isoneofthemostseriousissuesintermsofenvironmentalprotection.ProcessingofMSWwithoutfurtherdisastrouscontaminationcanbeachievedonlyinmodernizedmeasures,suchasincineratingandenergygeneratingconcurrently(Shen… 相似文献
327.
Chinese life cycle impact assessment factors 总被引:5,自引:0,他引:5
IntroductionLifecycleassessment(LCA)isanenvironmentalmanagementtoolthatisusedtoexamineandevaluatetheenvironmentalimpactsassociatedwiththeexistenceofproducts(Jensen,1998;Weidema,1997;Wenzel,1997).ThefocusofLCAisontheentirelifecycleoftheproduct,i.e.fromtheextracti… 相似文献
328.
Three cases of unusual chromosomal mosaicism are reported for which the cytogenetic data show inconsistent findings between CVS and AC or fetal tissue, and which cannot be explained simply by non-disjunction. For case 1, in CVS the karyotype was 46,XY, whereas lymphocytes and fibroblasts revealed 69,XXY. DNA fingerprinting indicated one paternal and two maternal chromosome sets, the latter most probably due to omission of maternal meiosis II. For case 2, in CVS mos 46,XX/47,XX,+mar de novo was observed. Amniotic fluid cells had the karyotype 46,XX. The origin of the marker chromosome might be explained by at least two events of unknown order (a somatic chromosome/chromatid deletion and non-disjunction of the homologous chromosome). In case 3 (CVS: mos 46,XY/46,XY,19q+ de novo; amniotic fluid cells, lymphocytes, and fibroblasts: 46,XY), the surplus of chromosome material in 19q+ might be explained on the basis of a somatic translocation. The idea of a chimera is less convincing, as the mosaic finding is restricted to one tissue. Furthermore, there was no hint of a vanishing twin. Hitherto, no case of structural chromosome mosaicism in CVS has been reconfirmed in fetal tissues. 相似文献
329.
D. J. H. Brock 《黑龙江环境通报》1994,14(13):1243-1252
A number of different models of CF carrier screening have now been tested in pilot trials. Apart from opportunistic and cascade testing (which are strictly speaking not true forms of screening), the major programmes have been directed either to young adults in primary care or to pregnant women in antenatal clinics. Only in the latter form of screening has sufficient data been collected to allow conclusions to be reached on the optimum mode of delivery. It seems very probable that when CF carrier screening passes into routine service, it will be the antenatal couple model that is used. 相似文献
330.
We report the first prenatal diagnosis of an affected fetus with Chediak-Higashi syndrome (CHS). Diagnosis was accomplished via fetal blood sampling at 17 menstrual weeks and was confirmed after birth. Retrospective measurement of the largest acid phosphatase-positive lysosomes in cultured amniotic fluid cells and chorionic villus cells showed that in CHS these lysosomes are significantly larger than those in normal cells. This method may be used for prenatal diagnosis of CHS by amniocentesis and chorionic villus sampling (CVS). 相似文献