全文获取类型
收费全文 | 449篇 |
免费 | 26篇 |
国内免费 | 1篇 |
出版年
2023年 | 7篇 |
2022年 | 11篇 |
2021年 | 21篇 |
2020年 | 11篇 |
2019年 | 15篇 |
2018年 | 11篇 |
2017年 | 11篇 |
2016年 | 23篇 |
2015年 | 26篇 |
2014年 | 26篇 |
2013年 | 32篇 |
2012年 | 31篇 |
2011年 | 41篇 |
2010年 | 10篇 |
2009年 | 10篇 |
2008年 | 23篇 |
2007年 | 32篇 |
2006年 | 13篇 |
2005年 | 18篇 |
2004年 | 9篇 |
2003年 | 14篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 6篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1967年 | 2篇 |
排序方式: 共有476条查询结果,搜索用时 31 毫秒
81.
82.
Jae-Hoon HwangJeong-A Choi Reda A.I. Abou-Shanab Booki MinHocheol Song Yongje Kim Eung Seok LeeByong-Hun Jeon 《Bioresource technology》2011,102(2):1051-1058
Anaerobic fermentation for hydrogen (H2) production was studied in a two-stage fermentation system fed with different ripened fruit feedstocks (apple, pear, and grape). Among the feedstocks, ripened apple was the most efficient substrate for cumulative H2 production (4463.7 mL-H2 L−1-culture) with a maximum H2 yield (2.2 mol H2 mol−1 glucose) in the first stage at a hydraulic retention time (HRT) of 18 h. The additional cumulative biohydrogen (3337.4 mL-H2 L−1-culture) was produced in the second stage with the reused residual substrate from the first stage. The major byproducts in this study were butyrate, acetate, and ethanol, and butyrate was dominant among them in all test runs. During the two-stage system, the energy efficiency (H2 conversion) obtained from mixed ripened fruits (RF) increased from 4.6% (in the first stage) to 15.5% (in the second stage), which indicated the energy efficiency can be improved by combined hydrogen production process. The RF could be used as substrates for biohydrogen fermentation in a two-stage (dark/dark) fermentation system. 相似文献
83.
84.
Mapping stakeholder viewpoints in biodiversity management: an application in Niger using Q methodology 总被引:1,自引:0,他引:1
Issa Hamadou Nassim Moula Seyni Siddo Moumouni Issa Hamani Marichatou Pascal Leroy Nicolas Antoine-Moussiaux 《Biodiversity and Conservation》2016,25(10):1973-1986
The purpose of this paper is to examine the viewpoints of stakeholders in the management and conservation of farm animal biodiversity in Niger. The research applies Q methodology in order to reveal consensual and divergent discourses. After the development of the set of items on the topic of biodiversity (Q sample), the statements were sorted by the respondents through a 7-grade scale, from ?3 to +3. The analysis of Q-sort data with the qmethod package under the R software highlighted three distinct stakeholder viewpoints on the importance of biodiversity in agriculture and animal husbandry, the balance between progress and preservation and the effectiveness of different methods of conservation. The study shows an apparent consensus on the importance of biodiversity that is obviously a promoted topic in the country. Behind the consensus, different discourses are defined that all appear divided by the same dilemma between conservation and economic development. Understanding the different answers and weight attributed to each of the components of the dilemma will guide awareness-raising campaigns and help to pinpoint divergent interests among stakeholders. 相似文献
85.
Lynn Grignard Bronner P. Gonçalves Angela M. Early Rachel F. Daniels Alfred B. Tiono Wamdaogo M. Guelbéogo Alphonse Ouédraogo Elke M. van Veen Kjerstin Lanke Amidou Diarra Issa Nebie Sodiomon B. Sirima Geoff A. Targett Sarah K. Volkman Daniel E. Neafsey Dyann F. Wirth Teun Bousema Chris Drakeley 《International journal for parasitology》2018,48(8):671-677
Plasmodium falciparum malaria infections often comprise multiple distinct parasite clones. Few datasets have directly assessed infection complexity in humans and mosquitoes they infect. Examining parasites using molecular tools may provide insights into the selective transmissibility of isolates. Using capillary electrophoresis genotyping and next generation amplicon sequencing, we analysed complexity of parasite infections in human blood and in the midguts of mosquitoes that became infected in membrane feeding experiments using the same blood material in two West African settings. Median numbers of clones in humans and mosquitoes were higher in samples from Burkina Faso (4.5, interquartile range 2–8 for humans; and 2, interquartile range 1–3 for mosquitoes) than in The Gambia (2, interquartile range 1–3 and 1, interquartile range 1–3, for humans and mosquitoes, respectively). Whilst the median number of clones was commonly higher in human blood samples, not all transmitted alleles were detectable in the human peripheral blood. In both study sample sets, additional parasite alleles were identified in mosquitoes compared with the matched human samples (10–88.9% of all clones/feeding assay, n?=?73 feeding assays). The results are likely due to preferential amplification of the most abundant clones in peripheral blood but confirm the presence of low density clones that produce transmissible sexual stage parasites. 相似文献
86.
Lukas?J.?MotlochEmail author Tina?Gebing Sara?Reda Astrid?Schwaiger Martin?Wolny Uta?C.?Hoppe 《The Journal of membrane biology》2016,249(4):577-584
Mitochondrial Ca2+ uptake (mCa2+ uptake) is thought to be mediated by the mitochondrial Ca2+ uniporter (MCU). UCP2 and UCP3 belong to a superfamily of mitochondrial ion transporters. Both proteins are expressed in the inner mitochondrial membrane of the heart. Recently, UCP2 was reported to modulate the function of the cardiac MCU related channel mCa1. However, the possible role of UCP3 in modulating cardiac mCa2+ uptake via the MCU remains inconclusive. To understand the role of UCP3, we analyzed cardiac mCa1 single-channel activity in mitoplast-attached single-channel recordings from isolated murine cardiac mitoplasts, from adult wild-type controls (WT), and from UCP3 knockout mice (UCP3–/–). Single-channel registrations in UCP3?/? confirmed a murine voltage-gated Ca2+ channel, i.e., mCa1, which was inhibited by Ru360. Compared to WT, mCa1 in UCP3?/? revealed similar single-channel characteristics. However, in UCP3?/? the channel exhibited decreased single-channel activity, which was insensitive to adenosine triphosphate (ATP) inhibition. Our results suggest that beyond UCP2, UCP3 also exhibits regulatory effects on cardiac mCa1/MCU function. Furthermore, we speculate that UCP3 might modulate previously described inhibitory effects of ATP on mCa1/MCU activity as well. 相似文献
87.
Abdulrahman Nabeel Jaballah Maiy Poomakkoth Noufira Riaz Sadaf Abdelaziz Somaia Issa Aya Mraiche Fatima 《Molecular and cellular biochemistry》2016,420(1-2):21-28
88.
Sixty-eight bacterial cultures were isolated from 5 archaeological soils in Egypt. It is necessary to characterize bacteria from ancient temples to develop protection programs for such archaeological places. Purified bacterial cultures were then tested for their capability to inhibit some multi-drug resistant (MDR) pathogenic bacteria including Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Escherichia coli and Klebsiella pneumoniae. Among the most active 10 antibacterial isolates, only one isolate designated as S5I4 was selected, characterized and identified as belonging to Bacillus amyloliquefaciens. The strain identification was confirmed by amplification of its 16S rRNA gene. The partial nucleotide sequence of the amplified 16S rRNA gene of the tested strain was submitted in GenBank with accession number AB813716. The physical and nutritional parameters were optimized to improve the production of antimicrobial agents by the B. amyloliquefaciens S5I4. The maximum antagonistic effect of this strain against the tested MDR pathogenic bacteria was achieved in presence of 1% galactose and 0.5% yeast extract at 37°C and pH 7.0 after 48 h incubation. The antibacterial compounds of B. amyloliquefaciens S5I4 were extracted, purified and characterized using spectroscopic analysis (IR, UV, proton NMR and MS). The compound having inhibitory activity was identified as butanedioic acid, octadecyl,1(1carboxy1methylethyl) 4octyl ester. 相似文献
89.
The present study demonstrated the growth of two species of cyanobacteria on wastewater isolated from sewage plant in Aswan, Egypt. We evaluated their efficiency for eliminating nitrogen, phosphorus, chemical oxygen demand (COD) and heavy metals (Fe2+, Pb2+, Cu2+, and Mn2+). The growth of Cyanosarcina fontana has supported wastewater as a growth medium than Anabaena oryzae compared to standard medium. The nutrients concentration such as COD, NO3–N and PO4–P were decreased by the growth of A. oryzae and C. fontana in the wastewater after primary settling and centrate. However, the reduction of COD was less efficient than the other nutrients. The reduction percentage of COD, NO3–N and PO4–P reached 39.3, 84.1 and 90.7% as well as 54.6, 83.1, and 89.8%, in cultures of A. oryzae and C. fontana grown in the wastewater after primary settling, respectively. The reduction amounted to 10.1, 76.8, and 63.0% by A. oryzae and 43.2, 62.1, and 74.8% by C. fontana, grown in the centrate, respectively. Cyanobacteria species have the ability to accumulate the heavy metals from the wastewater to level far than the exceeding metal level in the water. Whereas, the heavy metals biosorption performance of C. fontana was higher in accumulating Fe2+ (93.95%), Pb2+ (81.21%), Cu2+ (63.9%), and Mn2+ (48.49%) compared to A. oryzae. The biosorption ability is dependent on the nature of the adsorbent studied and the type of wastewater treated. Therefore, removal of heavy metals and nutrients by the tested algae is strongly recommended as a powerful technique for the removal of pollutants from wastewater. 相似文献
90.
Souma?la Pagabeleguem Geoffrey Gimonneau Momar Talla Seck Marc J. B. Vreysen Baba Sall Jean-Baptiste Rayaissé Issa Sidibé Jérémy Bouyer Sophie Ravel 《PLoS neglected tropical diseases》2016,10(2)