全文获取类型
收费全文 | 19101篇 |
免费 | 203篇 |
国内免费 | 172篇 |
专业分类
安全科学 | 561篇 |
废物处理 | 792篇 |
环保管理 | 2777篇 |
综合类 | 2561篇 |
基础理论 | 5119篇 |
环境理论 | 4篇 |
污染及防治 | 5394篇 |
评价与监测 | 1256篇 |
社会与环境 | 874篇 |
灾害及防治 | 138篇 |
出版年
2022年 | 137篇 |
2021年 | 176篇 |
2020年 | 111篇 |
2019年 | 153篇 |
2018年 | 266篇 |
2017年 | 266篇 |
2016年 | 439篇 |
2015年 | 368篇 |
2014年 | 524篇 |
2013年 | 1606篇 |
2012年 | 651篇 |
2011年 | 831篇 |
2010年 | 653篇 |
2009年 | 750篇 |
2008年 | 864篇 |
2007年 | 928篇 |
2006年 | 820篇 |
2005年 | 680篇 |
2004年 | 705篇 |
2003年 | 659篇 |
2002年 | 643篇 |
2001年 | 772篇 |
2000年 | 577篇 |
1999年 | 326篇 |
1998年 | 250篇 |
1997年 | 243篇 |
1996年 | 288篇 |
1995年 | 280篇 |
1994年 | 263篇 |
1993年 | 243篇 |
1992年 | 220篇 |
1991年 | 192篇 |
1990年 | 220篇 |
1989年 | 197篇 |
1988年 | 191篇 |
1987年 | 180篇 |
1986年 | 161篇 |
1985年 | 152篇 |
1984年 | 188篇 |
1983年 | 182篇 |
1982年 | 176篇 |
1981年 | 181篇 |
1980年 | 142篇 |
1979年 | 171篇 |
1978年 | 114篇 |
1977年 | 106篇 |
1976年 | 92篇 |
1975年 | 96篇 |
1973年 | 93篇 |
1972年 | 99篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
Joe Leigh Simpson James L. Mills George G. Rhoads George C. Cunningham Howard J. Hoffman Mary R. Conley 《黑龙江环境通报》1991,11(8):641-648
No clear answer concerning whether multivitamin/folate supplementation prevents neural tube defects (NTDs) is provided by three studies in the United States. All these studies are occurrence in nature, no recurrence studies having been conducted. The Atlanta Birth Defects Study is subject to pronounced memory and recall biases, the length between event and interview being as long as 16 years. In a second study (Boston University), objections can be raised to certain aspects of the experimental design, and the claim that 22 per cent of women started vitamins sufficiently early after pregnancy diagnosis to influence NTD formation is suspicious. Our NICHD case control study of 541 women in California and Illinois revealed no evidence for multivitamins or folic acid preventing NTDs. U.S. public policy-makers face difficulties in applying results of recurrence or occurrence studies in high-risk areas to low-risk areas in the U.S. 相似文献
972.
Dr. J. F. Bruch P. Metezeau N. Garcia-Fonknechten Y. Richard V. Tricottet B.-L. Hsi A. Kitzis C. Julien E. Papiernik 《黑龙江环境通报》1991,11(10):787-798
Three monoclonal antibodies (MAbs) against trophoblast (GB17, GB21, and GB25) and flow cytometry were used to sort trophoblast-like cells (TLCs) from peripheral blood of pregnant women. Sorted TLCs were processed for electron microscopy and fetal DNA amplification of the Y-specific sequences from mothers carrying male fetuses. At the ultra-structural level, most of the nucleated cells had the morphology of leucocytes, suggesting maternal contaminants, and we did not find the characteristic features of the free inter-villous trophoblast cells. Nevertheless, polymerase chain reaction (PCR) analysis showed an amplification of Y-specific sequences in two out of three samples of sorted TLCs. These results suggest that besides the maternal leucocytes, sufficient trophoblast nucleated fetal cells can be obtained using cell enrichment by sorting. This sensitive method holds promise for non-invasive prenatal diagnosis of fetal sex and if sufficient Y(positive) nuclei are found, for the diagnosis of selected numerical chromosome abnormalities. 相似文献
973.
E. Keller Dipl.-Biol. A. Andreas S. Scholz H. C. Dörr D. Knorr E. D. Albert 《黑龙江环境通报》1991,11(11):827-840
In 19 pregnancies at risk for 21-hydroxylase deficiency (21OHD) in 18 families with at lea one affected child, prenatal diagnosis was performed by RFLP analysis using the enzymi Taq I and EcoRI and the DNA probes specific for the 21 OH genes, the closely linke complement C4 genes and the highly polymorphic HLA class II genes DRB, DQB, and DPI For fetal DNA analysis either chorionic villi or cultivated amniotic cells were used. In all 1 cases, a clear prenatal diagnosis was possible either with the 21OH probe alone or in mo cases, by combining the results of the different closely linked loci. 相似文献
974.
Siegfried Rotmensch Marco Liberati Jia-Sen Luo Giovanni Tallin Maurice J. Mahoney John C. Hobbins 《黑龙江环境通报》1991,11(11):867-873
Many authors have suggested that individuals affected by a terminal 1q deletion display a phenotypically definable and recognizable syndrome. In all of the 27 cases reported to date, the breakpoints were at band q42 or distally to it. To our knowledge, we report the first case of a terminal 1q41 deletion. Diagnosis was made prenatally by amniocentesis, following ultrasonographic diagnosis of omphalocele, cerebral ventriculomegaly, and increased nuchal fold thickness in a 19-week female fetus. Multiple facial and extremity features were consistent with the proposed distal 1q deletion syndrome; omphalocele, however, has not been reported previously. The absence of liver herniation into the omphalocele sac in this case supports the previously reported association of this finding with chromosomal anomalies. 相似文献
975.
Introduction
This study examined the impact of the British Petroleum (BP) Baker Panel Report, reviewing the March 2005 BP-Texas City explosion, on the field of process safety.Method
Three hundred eighty-four subscribers of a process safety listserv responded to a survey two years after the BP Baker Report was published.Results
Results revealed respondents in the field of process safety are familiar with the BP Baker Report, feel it is important to the future safety of chemical processing, and believe that the findings are generalizable to other plants beyond BP-Texas City. Respondents indicated that few organizations have administered the publicly available BP Process Safety Culture Survey. Our results also showed that perceptions of contractors varied depending on whether respondents were part of processing organizations (internal perspective) or government or consulting agencies (external perspective).Conclusions
This research provides some insight into the beliefs of chemical processing personnel regarding the transportability and generalizability of lessons learned from one organization to another.Impact on Industry
This study has implications for both organizational scientists and engineers in that it reveals perceptions about the primary mechanism used to share lessons learned within one industry about one major catastrophe (i.e., investigation reports). This study provides preliminary information about the perceived impact of a report such as this one. 相似文献976.
Introduction
Falls in older Australians are a significant public health issue with one in three older people falling one or more times each year.Method
Many fall prevention randomized controlled trials have been conducted in Australia as well as across the world.Results
The findings of these studies now constitute a substantial evidence base that can provide direction for health and lifestyle interventions for preventing falls in older people. This research evidence has contributed to health policy in Australia to some extent, but is yet to be widely implemented into practice. This opinion piece overviews previous policy initiatives and describes a new Partnership research program funded by the Australian National Health and Medical Research Council (NHMRC), which seeks to further influence health policy and address the ongoing research-practice gap. 相似文献977.
Ahmad N. Abou Tayoun Nancy B. Spinner Heidi L. Rehm Robert C. Green Diana W. Bianchi 《黑龙江环境通报》2018,38(1):26-32
Clinical diagnostic laboratories are producing next-generation sequencing-based test results that are becoming increasingly incorporated into patient care. Whole genome and exome sequencing on fetal material derived from amniocytes, chorionic villi, or products of conception is starting to be offered clinically in specialized centers, but it has not yet become routine practice. The technical, interpretation, and ethical challenges are greatest in the area of prenatal medicine because the fetus has a limited health history, and the physical examination is only indirectly available via prenatal sonography. Here, we provide an overview of these challenges and highlight the clinical utility, reporting, and counseling issues associated with prenatal DNA sequencing. Future considerations are also discussed. © 2017 John Wiley & Sons, Ltd. 相似文献
978.
979.
980.
Adedibu C. Tell Samson O. Owalude Sunday J. Olatunji Vincent O. Adimul Sunday E. Elaigwu Lukman O. Alimi Peter A. Ajibade Oluwatobi S. Oluwafemi 《环境科学学报(英文版)》2018,30(2):264-275
We herein report the removal of amodiaquine, an emerging drug contaminant from aqueous solution using [Zn2(fum)2(bpy)] and [Zn4 O(bdc)3](fum = fumaric acid; bpy =4,4-bipyridine; bdc = benzene-1,4-dicarboxylate) metal–organic frameworks(MOFs) as adsorbents. The adsorbents were characterized by elemental analysis, Fourier transform infrared(FT-IR) spectroscopy, and powder X-ray diffraction(PXRD). Adsorption process for both adsorbents were found to follow the pseudo-first-order kinetics, and the adsorption equilibrium data fitted best into the Freundlich isotherm with the R~2 values of 0.973 and0.993 obtained for [Zn_2(fum)_2(bpy)] and [Zn_4 O(bdc)_3] respectively. The maximum adsorption capacities foramodiaquine in this study were found to be 0.478 and 47.62 mg/g on the[Zn_2(fum)_2(bpy)] and [Zn_4 O(bdc)_3] MOFs respectively, and were obtained at p H of 4.3 for both adsorbents. FT-IR spectroscopy analysis of the MOFs after the adsorption process showed the presence of the drug. The results of the study showed that the prepared MOFs could be used for the removal of amodiaquine from wastewater. 相似文献