全文获取类型
收费全文 | 697篇 |
免费 | 23篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 32篇 |
废物处理 | 10篇 |
环保管理 | 173篇 |
综合类 | 57篇 |
基础理论 | 218篇 |
环境理论 | 1篇 |
污染及防治 | 138篇 |
评价与监测 | 57篇 |
社会与环境 | 22篇 |
灾害及防治 | 18篇 |
出版年
2023年 | 7篇 |
2022年 | 7篇 |
2021年 | 9篇 |
2020年 | 14篇 |
2019年 | 8篇 |
2018年 | 21篇 |
2017年 | 27篇 |
2016年 | 35篇 |
2015年 | 22篇 |
2014年 | 21篇 |
2013年 | 71篇 |
2012年 | 33篇 |
2011年 | 41篇 |
2010年 | 35篇 |
2009年 | 32篇 |
2008年 | 40篇 |
2007年 | 33篇 |
2006年 | 35篇 |
2005年 | 16篇 |
2004年 | 28篇 |
2003年 | 17篇 |
2002年 | 15篇 |
2001年 | 8篇 |
2000年 | 12篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 10篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 12篇 |
1993年 | 8篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1974年 | 2篇 |
1968年 | 1篇 |
1954年 | 1篇 |
1930年 | 1篇 |
排序方式: 共有726条查询结果,搜索用时 15 毫秒
671.
672.
Aishwarya Arjunan Holly Bellerose Raul Torres Rotem Ben-Shachar Jodi D. Hoffman Brad Angle Robert Nathan Slotnick Brittany N. Simpson Andrea M. Lewis Pilar L. Magoulas Kelly Bontempo Jeanine Schulze Jennifer Tarpinian Jessica A. Bucher Richard Dineen Allison Goetsch Gabriel A. Lazarin Katherine Johansen Taber 《黑龙江环境通报》2020,40(10):1246-1257
Background
Disease severity is important when considering genes for inclusion on reproductive expanded carrier screening (ECS) panels. We applied a validated and previously published algorithm that classifies diseases into four severity categories (mild, moderate, severe, and profound) to 176 genes screened by ECS. Disease traits defining severity categories in the algorithm were then mapped to four severity-related ECS panel design criteria cited by the American College of Obstetricians and Gynecologists (ACOG).Methods
Eight genetic counselors (GCs) and four medical geneticists (MDs) applied the severity algorithm to subsets of 176 genes. MDs and GCs then determined by group consensus how each of these disease traits mapped to ACOG severity criteria, enabling determination of the number of ACOG severity criteria met by each gene.Results
Upon consensus GC and MD application of the severity algorithm, 68 (39%) genes were classified as profound, 71 (40%) as severe, 36 (20%) as moderate, and one (1%) as mild. After mapping of disease traits to ACOG severity criteria, 170 out of 176 genes (96.6%) were found to meet at least one of the four criteria, 129 genes (73.3%) met at least two, 73 genes (41.5%) met at least three, and 17 genes (9.7%) met all four.Conclusion
This study classified the severity of a large set of Mendelian genes by collaborative clinical expert application of a trait-based algorithm. Further, it operationalized difficult to interpret ACOG severity criteria via mapping of disease traits, thereby promoting consistency of ACOG criteria interpretation.673.
674.
The Microbial Assay for Risk Assessment (MARA) is an innovative system based on an array of 11 different microbial species freeze-dried in a 96-well micro-titre plate format. Developed for testing the toxicity of chemicals, mixtures and environmental samples, the assay employs species of a taxonomically diverse range. In addition to ten prokaryotic species, a eukaryote (yeast) is included in the range. The MARA's innate scope of a multi-dimensional test allows determination of toxicity based on a unique assay fingerprint or index, numerically expressed as the mean Microbial Toxic Concentration (MTC). The most significant potential of the test is in the additional inference that can be conveyed to the toxicity evaluation because of the presence of each of the constituent species. In view of the fact that conventional aquatic bioassays, like fish or cladoceran tests, are expensive and impractical, the MARA could provide a cost-effective solution for routine ecotoxicological testing. The performance of the MARA was evaluated to ascertain its capability and potential scope. Sensitivity to toxicants and different environmental samples was assessed. Evaluation included comparison with other tests: namely Microtox, invertebrate (Daphnia magna and Thamnocephalus platyurus) microbiotests, and respiration-inhibition and nitrification-inhibition tests. The most sensitive invertebrate test was found to be the T. platyurus microbiotest for three of the four metals tested. The LC(50) values for this test for Cd(ii), Cr(vi) and As(iii) were 0.2, 0.018 and 0.3 mg l(-1), respectively; and the corresponding most sensitive MARA species MTC values were 4.4, 2.8 and 17 mg l(-1), respectively. 相似文献
675.
Daniella Rogerson Anna Alkelai Jessica Giordano Madhulatha Pantrangi Meng-Chang Hsiao Chia-Ling Nhan-Chang Joshua E. Motelow Vimla Aggarwal David Goldstein Ron Wapner Carrie J. Shawber 《黑龙江环境通报》2023,43(6):703-716
Objective
Congenital lymphatic anomalies (LAs) arise due to defects in lymphatic development and often present in utero as pleural effusion, chylothorax, nuchal and soft tissue edema, ascites, or hydrops. Many LAs are caused by single nucleotide variants, which are not detected on routine prenatal testing.Methods
Demographic data were compared between two subcohorts, those with clinically significant fetal edema (CSFE) and isolated fetal edema. A targeted variant analysis of LA genes was performed using American College of Medical Genetics criteria on whole exome sequencing (WES) data generated for 71 fetal edema cases who remained undiagnosed after standard workup.Results
CSFE cases had poor outcomes, including preterm delivery, demise, and maternal preeclampsia. Pathogenic and likely pathogenic variants were identified in 7% (5/71) of cases, including variants in RASopathy genes, RASA1, SOS1, PTPN11, and a novel PIEZO1 variant. Variants of uncertain significance (VOUS) were identified in 45% (32/71) of cases. In CSFEs, VOUS were found in CELSR1, EPHB4, TIE1, PIEZO1, ITGA9, RASopathy genes, SOS1, SOS2, and RAF1.Conclusions
WES identified pathogenic and likely pathogenic variants and VOUS in LA genes in 51% of fetal edema cases, supporting WES and expanded hydrops panels in cases of idiopathic fetal hydrops and fluid collections. 相似文献676.
Symbion americanus was recently described as the second species in the phylum Cycliophora, living commensally on the American commercial lobster
Homarus americanus. A previous genetic analysis of American and European populations of cycliophorans suggested that haplotype divergence in
S. americanus was much greater than in its European counterpart S. pandora. This study examined the population structure and demographics of 169 individuals thought to belong to S. americanus collected from lobsters over 13 North American localities (Nova Scotia, Canada to Maryland, USA) between October 2003 and
January 2006. Cytochrome c oxidase subunit I sequence data clearly suggested the presence of three cryptic lineages in a species complex, often co-occurring
in the same lobster specimens. One of these lineages, named the “G” lineage, was represented by very few individuals and therefore
was excluded from subsequent statistical analyses. The other two sympatric lineages, named the “T” and “C” lineages, showed
different population structure and demography. Although limited geographic structure was found in the T lineage, the C lineage
showed higher nucleotide and haplotype diversity values, as well as more variation between localities. The data also indicated
that the T lineage underwent a recent population expansion, suggesting that the C and T lineages may have speciated in allopatry
but a subsequent population expansion may have been responsible for their current sympatric distribution. Studies on the anatomy
and ecology of the sympatric lineages of this species complex should provide further information on the identity of the holotype
of S. americanus, which currently cannot be ascribed to any of the three cryptic lineages. 相似文献
677.
Despite the importance of the gills in the acquisition of food by suspension-feeding bivalve mollusks, there is almost no
information on gill organogenesis. By means of a series of stereoscan electron micrographs, this paper describes gill development
in the Chilean oyster, Ostrea chilensis, from the brooded larval stages to 1-month-old spat. A single gill rudiment was observed on each side of the mantle at a
shell length of 320 μm, and the rudiments increased in number and size until the end of the brooding period. During metamorphosis
the gill filaments increased in number from 5 or 6 to between 7 and 9. The loss of the velum and the absence of functional
gill filaments during metamorphosis are consistent with previous observations of weight loss during this critical period of
the life history, because the newly settled juvenile lacks the ability to remove particles from suspension. The end of metamorphosis
(100% of spat with dissoconch edge) was reached 36 h after larval settlement, when the gill filaments began to grow cilia,
which increased in density and differentiated as the spat developed and acquired the capability of suspension-feeding, accounting
for the increase in body weight previously recorded during this stage. The larval rudiments gave rise to the inner demibranchs.
The outer demibranchs were observed 10 days after settlement, located between the inner demibranch and the mantle. In 1-month-old
spat, the gill did not show differentiation between primary and secondary filaments, indicating that the heterorhabdic condition
characteristic of adult oysters had yet to be attained.
Received: 11 December 1998 / Accepted: 21 August 2000 相似文献
678.
W.A Thompson C.S Holling D Kira C.C Huang I Vertinskf 《Journal of Environmental Economics and Management》1979,6(1):51-68
A major difficulty in choosing a forest management policy that regulates yearly spraying and logging levels is the fact that such a choice involves comparisons among risky alternatives. Practical and theoretical constraints often make the specification of a utility function for the system infeasible. This paper demonstrates that by making reasonable and easily verifiable assumptions about some properties of preference profiles of participants in the system, it is possible to produce an effective algorithm for forest policy evaluation. The method proposed and applied to the case of the New Brunswick forests consists of: (1) construction of a forest simulation to generate policy contingent distributions of outcomes, and (2) employment of stochastic dominance to identify a nondominated set of policies. 相似文献
679.
Mytilus trossulus Gould and M. edulis L. coexist in mixed populations in Atlantic Canadian waters. Although there is evidence that the two species hybridize in
natural populations and that hybrids produce progeny through backcrosses, no study of the microgeographic distribution of
the two forms and their hybrids has been made. Here we examine subtidal samples of mussels taken in July 1997 from two locations
in eastern Newfoundland (Canada) and from wave-exposed and protected environments within each location. Shell lengths ranged
from 15 to about 90 mm. Mussels were classified as pure forms or hybrids (F1, F2 and from backcrosses) based on four diagnostic markers, two allozyme loci (Mpi and Est-D) and two nuclear PCR-based DNA markers (ITS and Glu-5). In addition, a PCR-based mtDNA marker (COIII) was used to characterize the distribution of mtDNA mitotypes among pure and hybrid individuals. There were differences in
the proportions of pure M. edulis and M. trossulus between sites and between environments at one location. M. trossulus was the predominant species at one of the two exposed sites. In all four samples, M. trossulus was also the predominant form among small individuals. The frequency of hybrids was 26% overall and did not differ among
samples. Hybrids consisted mostly of backcrosses that were M. trossulus-biased among small mussels and M. edulis-biased among large ones. We conclude that both intrinsic genetic factors and extrinsic environmental factors influence the
relative frequency of M. edulis, M. trossulus and their hybrids.
Received: 29 June 1998 / Accepted: 4 November 1998 相似文献
680.
Borth Priscila Liane Biesdorf Perin Jessica Klarosk Helenas Torrecilhas Arthur Ribeiro Pan Nicole Caldas Kuroda Emília Kiyomi Fernandes Fernando 《Journal of Material Cycles and Waste Management》2021,23(5):1974-1983
Journal of Material Cycles and Waste Management - The objective of this study is to evaluate the influence of the addition of garden waste (GW) on the performance of food waste (FW) anaerobic... 相似文献