全文获取类型
收费全文 | 141篇 |
免费 | 12篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 8篇 |
2014年 | 10篇 |
2013年 | 14篇 |
2012年 | 12篇 |
2011年 | 10篇 |
2010年 | 10篇 |
2009年 | 6篇 |
2008年 | 6篇 |
2007年 | 7篇 |
2006年 | 13篇 |
2005年 | 12篇 |
2004年 | 2篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1972年 | 1篇 |
1968年 | 2篇 |
排序方式: 共有153条查询结果,搜索用时 15 毫秒
111.
In this work we study a structured fishing model, basically displaying the two stages of the ages of a fish population, which are in our case juvenile, and adults. We associate to this model the maximization of the total discounted net revenues derived by the exploitation of the stock. The exploitation strategy of the optimal control problem is then developed and presented. 相似文献
112.
Feraud M Masclaux-Daubresse C Ferrario-Méry S Pageau K Lelandais M Ziegler C Leboeuf E Jouglet T Viret L Spampinato A Paganelli V Hammouda MB Suzuki A 《Planta》2005,222(4):667-677
GLU1 encodes the major ferredoxin-dependent glutamate synthase (Fd-GOGAT, EC 1.4.7.1) in Arabidopsis thaliana (ecotype Columbia). With the aim of providing clues on the role of Fd-GOGAT, we analyzed the expression of Fd-GOGAT in tobacco
(Nicotiana tabacum L. cv. Xanthi). The 5′ flanking element of GLU1 directed the expression of the uidA reporter gene in the palisade and spongy parenchyma of mesophyll, in the phloem cells of vascular tissue and in the roots
of tobacco. White light, red light or sucrose induced GUS expression in the dark-grown seedlings in a pattern similar to the GLU1 mRNA accumulation in Arabidopsis. The levels of GLU2 mRNA encoding the second Fd-GOGAT and NADH-glutamate synthase (NADH-GOGAT, EC 1.4.1.14) were not affected by light. Both
in the light and in darkness, 15NH4+ was incorporated into [5−15N]glutamine and [2−15N]glutamate by glutamine synthetase (GS, EC 6.3.1.2) and Fd-GOGAT in leaf disks of transgenic tobacco expressing antisense
Fd-GOGAT mRNA and in wild-type tobacco. In the light, low level of Fd-glutamate synthase limited the [2−15N]glutamate synthesis in transgenic leaf disks. The efficient dark labeling of [2−15N]glutamate in the antisense transgenic tobacco leaves indicates that the remaining Fd-GOGAT (15–20% of the wild-type activity)
was not the main limiting factor in the dark ammonium assimilation. The antisense tobacco under high CO2 contained glutamine, glutamate, asparagine and aspartate as the bulk of the nitrogen carriers in leaves (62.5%), roots (69.9%)
and phloem exudates (53.2%). The levels of glutamate, asparagine and aspartate in the transgenic phloem exudates were similar
to the wild-type levels while the glutamine level increased. The proportion of these amino acids remained unchanged in the
roots of the transgenic plants. Expression of GLU1 in mesophyll cells implies that Fd-GOGAT assimilates photorespiratory and primary ammonium. GLU1 expression in vascular cells indicates that Fd-GOGAT provides amino acids for nitrogen translocation.
The nucleotide sequence data of the GLU1 gene reported in the present study is available from GenBank with the following accession number: AY189525 相似文献
113.
Huimin Xu Houri Khalilian Mohamed Eweida Sam Squire Mounir G. Abouhaidar 《Plant cell reports》1995,15(1-2):91-96
The genes for the capsid protein (CP) and the 8K movement protein of PVX were introduced into potato (Solanum tuberosum L.) and expressed under the control of CaMV 35S promoter using a binary vector andAgrobacterium tumefaciens. Four commercial potato cultivars (Russet Burbank, Shepody, Desirée and Bintje) have been efficiently transformed. Eleven independent transgenic clones, with CP expression levels higher than 0.05% of the soluble leaf proteins, were analyzed for resistance to inoculation with PVX (5 and 50µg/ml). The resistance of the transgenic plants to PVX was observed with the lower titer of virus inoculation (5 µg/ml) but not with higher titer (50 µg/ml). A significant reduction in the accumulation of virus in the inoculated transgenic potato plants has been observed under greenhouse and field conditions. Furthermore, the CP gene is very stable and is transferred to new plants originated from stem cuttings or from tubers. The transgenic plants appeared to be phenotypically identical to the nontransformed controls.Abbreviations BAP
benzyl-aminopurine
- BCIP
5-bromo-4-chloro-3-indolylphosphate p-Toluidine salt
- CaMV
cauliflower mosaic virus
- CP
capsid protein
- GA3
gibberellic acid
- Kbp
kilobase pair
- NAA
naphthalene acetic acid
- NBT
nitroblue tetrazolium chloride
- NOS
nopaline synthase
- NPT II
neomycin phosphotransferase II
- PMSF
phenyl methyl sulfonyl fluoride
- PVX
potato virus X
- PVY
potato virus Y 相似文献
114.
Cyril Jousse Céline Dalle Isabelle Canet Marie Lagrée Mounir Traïkia Bernard Lyan Cédric Mendes Martine Sancelme Pierre Amato Anne-Marie Delort 《Metabolomics : Official journal of the Metabolomic Society》2018,14(1):11
Introduction
Active microorganisms have been recently discovered in clouds, thus demonstrating the capacity of microorganisms to exist in harsh environments, including exposure to UV and oxidants, osmotic and cold shocks, etc. It is important to understand how microorganisms respond to and survive such stresses at the metabolic level.Objectives
The objective of this work is to assess metabolome modulation in a strain of Pseudomonas syringae isolated from cloud water and facing temperature downshift from 17 to 5 °C by identifying key molecules and pathways of the response/adaptation to cold shock.Methods
Bacterial extracts from suspensions of cells grown at 17 °C and further incubated in microcosms at 5 and 17 °C to mimic cloud conditions were analysed by combining LC-MS and NMR; the results were evaluated in comparison to similar suspensions kept at constant temperature. The differences in the metabolome profiles were deciphered using multivariate statistics (PLS-DA).Results
Key cold shock biomarkers were observed, including cryoprotectants (trehalose, glucose, glycerol, carnitine, glutamate), antioxidants (glutathione and carnitine) and their precursors, alkaloids (bellendine and slaframine) and metabolites involved in energy metabolism (ATP, carbohydrates). Furthermore, new short peptides (nine dipeptides and a tetrapeptide) were found that have no known function.Conclusions
This study shows that in response to cold temperatures, Pseudomonas syringae PDD-32b-74 demonstrates numerous metabolism modifications to counteract the impacts of low temperatures.115.
Charles Coutton Guillaume Martinez Zine-Eddine Kherraf Amir Amiri-Yekta Magalie Boguenet Antoine Saut Xiaojin He Feng Zhang Marie Cristou-Kent Jessica Escoffier Marie Bidart Véronique Satre Béatrice Conne Selima Fourati Ben Mustapha Lazhar Halouani Ouafi Marrakchi Mounir Makni Habib Latrous Pierre F. Ray 《American journal of human genetics》2019,104(2):331-340
116.
Zoe Cournia Toby W. Allen Ioan Andricioaei Bruno Antonny Daniel Baum Grace Brannigan Nicolae-Viorel Buchete Jason T. Deckman Lucie Delemotte Coral del Val Ran Friedman Paraskevi Gkeka Hans-Christian Hege Jérôme Hénin Marina A. Kasimova Antonios Kolocouris Michael L. Klein Syma Khalid M. Joanne Lemieux Norbert Lindow Mahua Roy Jana Selent Mounir Tarek Florentina Tofoleanu Stefano Vanni Sinisa Urban David J. Wales Jeremy C. Smith Ana-Nicoleta Bondar 《The Journal of membrane biology》2015,248(4):611-640
117.
A novel function of eIF2alpha kinases as inducers of the phosphoinositide-3 kinase signaling pathway
下载免费PDF全文
![点击此处可从《Molecular biology of the cell》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kazemi S Mounir Z Baltzis D Raven JF Wang S Krishnamoorthy JL Pluquet O Pelletier J Koromilas AE 《Molecular biology of the cell》2007,18(9):3635-3644
Phosphoinositide-3 kinase (PI3K) plays an important role in signal transduction in response to a wide range of cellular stimuli involved in cellular processes that promote cell proliferation and survival. Phosphorylation of the alpha subunit of the eukaryotic translation initiation factor eIF2 at Ser51 takes place in response to various types of environmental stress and is essential for regulation of translation initiation. Herein, we show that a conditionally active form of the eIF2alpha kinase PKR acts upstream of PI3K and turns on the Akt/PKB-FRAP/mTOR pathway leading to S6 and 4E-BP1 phosphorylation. Also, induction of PI3K signaling antagonizes the apoptotic and protein synthesis inhibitory effects of the conditionally active PKR. Furthermore, induction of the PI3K pathway is impaired in PKR(-/-) or PERK(-/-) mouse embryonic fibroblasts (MEFs) in response to various stimuli that activate each eIF2alpha kinase. Mechanistically, PI3K signaling activation is indirect and requires the inhibition of protein synthesis by eIF2alpha phosphorylation as demonstrated by the inactivation of endogenous eIF2alpha by small interfering RNA or utilization of MEFs bearing the eIF2alpha Ser51Ala mutation. Our data reveal a novel property of eIF2alpha kinases as activators of PI3K signaling and cell survival. 相似文献
118.
Is long‐term protection useful for the regeneration of disturbed plant communities in dry areas?
下载免费PDF全文
![点击此处可从《African Journal of Ecology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mohamed Tarhouni Walid Ben Hmida Azaiez Ouled Belgacem Mounir Louhaichi Mohamed Neffati 《African Journal of Ecology》2017,55(4):509-517
In dry areas, natural plant communities are mainly affected by climatic stress and human disturbances – overgrazing, ploughing and biomass harvesting – that accelerate their degradation. Management techniques, including creation of national parks (fencing), are needed to conserve natural resources/biodiversity. The long‐term effects of protection on the plant communities should be monitored. This study assessed the results of long‐term protection on the composition and diversity of the natural plant communities of Sidi Toui National Park (southern Tunisia) using the point‐quadrat method and ecological indicators of the ecosystem structure. Comparison of these indicators for the period 1990–2011 inside (fenced) and outside (disturbed) the Park showed that regeneration of natural vegetation increased during the first decade of the fencing period (1990–2001), but declined during the period (2008–2011). After a long period of fencing, plant tufts were bigger and aged, and the ecosystem dynamics decreased. In the absence of animal activities, the hardpan at the soil surface impedes seedling emergence. This suggests that long‐term fencing is not recommended for conserving floral diversity in dryland ecosystems. To ensure and maintain the regeneration of these ecosystems, fencing periods alternating with controlled grazing (by introducing wild herbivores) are recommended. 相似文献
119.
Mounir El Guezzar Jean-Pierre Hornez Bernard Courtois Jean-Claude Derieux 《FEMS microbiology letters》1988,49(3):429-434
Abstract Rhizobium meliloti grows on fructose as sole carbon source. Following nitrosoguanidine mutagenesis, a mutant of R. meliloti M5N1 was isolated as unable to grow on fructose. Enzyme assays with cell-free extracts showed it to lack significative phosphoglucose isomerase activity. Other enzymes were present at low levels. Both fructose and fructose 6-phosphate were accumulated within this mutant. The in vitro inhibition of fructokinase by fructose 6-phosphate was show. Symbiotic properties remained unaffected in the mutant strain. 相似文献