全文获取类型
收费全文 | 1405篇 |
免费 | 119篇 |
出版年
2023年 | 9篇 |
2022年 | 19篇 |
2021年 | 27篇 |
2020年 | 20篇 |
2019年 | 26篇 |
2018年 | 24篇 |
2017年 | 21篇 |
2016年 | 37篇 |
2015年 | 82篇 |
2014年 | 87篇 |
2013年 | 100篇 |
2012年 | 154篇 |
2011年 | 120篇 |
2010年 | 113篇 |
2009年 | 82篇 |
2008年 | 85篇 |
2007年 | 95篇 |
2006年 | 90篇 |
2005年 | 71篇 |
2004年 | 73篇 |
2003年 | 57篇 |
2002年 | 60篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 10篇 |
1998年 | 9篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 3篇 |
1965年 | 1篇 |
1952年 | 1篇 |
排序方式: 共有1524条查询结果,搜索用时 31 毫秒
921.
Key impact of Vgt1 on flowering time adaptation in maize: evidence from association mapping and ecogeographical information 下载免费PDF全文
Ducrocq S Madur D Veyrieras JB Camus-Kulandaivelu L Kloiber-Maitz M Presterl T Ouzunova M Manicacci D Charcosset A 《Genetics》2008,178(4):2433-2437
An association study conducted on 375 maize inbred lines indicates a strong relationship between Vgt1 polymorphisms and flowering time, extending former quantitative trait loci (QTL) mapping results. Analysis of allele frequencies in a landrace collection supports a key role of Vgt1 in maize altilatitudinal adaptation. 相似文献
922.
923.
A better knowledge of the nitrogen nutrition of Medicago truncatula at the whole plant level and its modulation by environmental factors is a crucial step to reach a complete understanding of legume nitrogen nutrition. This study was based on the symbiotic system that is the most commonly used by the research community (M. truncatula cv. Jemalong A17 x Rhizobium meliloti strain 2011). Plant nitrogen nutrition was analysed in relation to carbon nutrition, under a range of nitrate concentrations in the nutrient solution and different light conditions. This study shows that this 'model symbiotic association' does not allow the plant to meet its nitrogen requirements, when dinitrogen fixation is the main nitrogen source for plant growth. A strong interaction between nitrogen and carbon nutrition was shown: when plant nitrogen requirements were not sustained, plant leaf area was much affected whereas photosynthesis per unit leaf area remained relatively stable. Both total nitrogen uptake and leaf area increased with increasing nitrate concentration in the nutrient solution; the magnitude of these responses varied according to the light conditions. Interestingly, the plant nitrogen nutrition level remained nearly unaffected by the light conditions. The observed nitrogen-limitation in this 'model symbiotic association' is an important finding for the research community. Based on practical recommendations regarding both the experimental conditions and the phenotypic traits to consider, a methodological framework was proposed to (i) help genomicists to assess plant nitrogen nutrition better, and (ii) assist in the detection of new genetic variants affected for nitrogen uptake in large-scale phenotyping studies. 相似文献
924.
Dumestre-Pérard C Lamy B Aldebert D Lemaire-Vieille C Grillot R Brion JP Gagnon J Cesbron JY 《Journal of immunology (Baltimore, Md. : 1950)》2008,181(10):7100-7105
Innate immunity is the major host defense against invasive aspergillosis. To determine whether the collectin mannan-binding lectin (MBL) is involved in the initial protective immunity through complement activation against opportunistic fungal infections caused by Aspergillus, we performed in vitro studies on 29 different strains of Aspergillus conidia from five different species. Incubation of Aspergillus conidia in human normal serum leads to activation of the alternative pathway, whereas neither the classical nor the lectin pathways through C4 and C2 cleavage are activated. Complement response to conidia was investigated using a MBL-deficient serum and reconstitution experiments were conducted with MBL/MASPs complexes. We found that MBL can directly support C3 activation by a C2 bypass mechanism. Finally, a stronger activation of the alternative pathway was observed for the clinical strains isolated from patients with invasive aspergillosis, compared with the environmental strains. 相似文献
925.
Delphine Haesaerts John A. Finlay Maureen E. Callow James A. Callow Philippe Grosjean Michel Jangoux 《Biofouling》2013,29(5-6):229-235
Abstract A turbulent channel flow apparatus was used to determine the adhesion strength of the three perimetamorphic stages of the asteroid Asterina gibbosa, i.e. the brachiolaria larvae, the metamorphic individuals and the juveniles. The mean critical wall shear stresses (wall shear stress required to dislodge 50% of the attached individuals) necessary to detach larvae attached by the brachiolar arms (1.2 Pa) and juveniles attached by the tube feet (7.1 Pa) were one order of magnitude lower than the stress required to dislodge metamorphic individuals attached by the adhesive disc (41 Pa). This variability in adhesion strength reflects differences in the functioning of the adhesive organs for these different life stages of sea stars. Brachiolar arms and tube feet function as temporary adhesion organs, allowing repetitive cycles of attachment to and detachment from the substratum, whereas the adhesive disc is used only once, at the onset of metamorphosis, and is responsible for the strong attachment of the metamorphic individual, which can be described as permanent adhesion. The results confirm that the turbulent water channel apparatus is a powerful tool to investigate the adhesion mechanisms of minute organisms. 相似文献
926.
Zied Riahi Hassen Hammami Houyem Ouragini Habib Messai Rim Zainine Yosra Bouyacoub Lilia Romdhane Donia Essaid Rym Kefi Mohsen Rhimi Monia Bedoui Afef Dhaouadi Delphine Feldmann Laurence Jonard Ghazi Besbes Sonia Abdelhak 《Gene》2013
Hearing loss is the most frequent sensory disorder. It affects 3 in 1000 newborns. It is genetically heterogeneous with 60 causally-related genes identified to date. Mutations in GJB2 gene account for half of all cases of non-syndromic deafness. The aim of this study was to determine the relative frequency of GJB2 allele variants in Tunisia. In this study, we screened 138 patients with congenital hearing loss belonging to 131 families originating from different parts of Tunisia for mutations in GJB2 gene. GJB2 mutations were found in 39% of families (51/131). The most common mutation was c.35delG accounting for 35% of all cases (46/131). The second most frequent mutation was p.E47X present in 3.8% of families. Four identified mutations in our cohort have not been reported in Tunisia; p.V37I, c.235delC, p.G130A and the splice site mutation IVS1+1G>A (0.76%). These previously described mutations were detected only in families originating from Northern and not from other geographical regions in Tunisia. In conclusion we have confirmed the high frequency of c.35delG in Tunisia which represents 85.4% of all GJB2 mutant alleles. We have also extended the mutational spectrum of GJB2 gene in Tunisia and revealed a more pronounced allelic heterogeneity in the North compared to the rest of the country. 相似文献
927.
Sylvain Ferrandon Paul Saultier Julien Carras Priscillia Battiston-Montagne Gersende Alphonse Michael Beuve Céline Malleval Jérôme Honnorat Tania Slatter Noelyn Hung Janice Royds Claire Rodriguez-Lafrasse Delphine Poncet 《Molecular neurobiology》2013,47(1):64-76
Despite a standard of care combining surgery, radiotherapy (RT), and temozolomide chemotherapy, the average overall survival (OS) of glioblastoma patients is only 15 months, and even far lower when the patient cannot benefit from this combination. Therefore, there is a strong need for new treatments, such as new irradiation techniques. Against this background, carbon ion hadrontherapy, a new kind of irradiation, leads to a greater biological response of the tumor, while minimizing adverse effects on healthy tissues in comparison with RT. As carbon ion hadrontherapy is restricted to RT-resistant patients, photon irradiation resistance biomarkers are needed. Long telomeres and high telomerase activity have been widely associated with photon radioresistance in other cancers. Moreover, telomere protection, telomere function, and telomere length (TL) also depend on the shelterin protein complex (TRF1, TRF2, TPP1, POT1, TIN2, and hRAP1). We thus decided to evaluate an enlarged telomeric status (TL, telomerase catalytic subunit, and the shelterin component expression level) as a potential radioresistance biomarker in vitro using cellular models and ex vivo using patient tumor biopsies. In addition, nothing was known about the role of telomeres in carbon ion response. We thus evaluated telomeric status after both types of irradiation. We report here a significant correlation between TL and the basal POT1 expression level and photon radioresistance, in vitro, and a significant increase in the OS of patients with long telomeres or a high POT1 level, in vivo. POT1 expression was predictive of patient response irrespective of the TL. Strikingly, these correlations were lost, in vitro, when considering carbon irradiation. We thus propose (1) a model of the implications of telomeric damage in the cell response to both types of irradiation and (2) assessment of the POT1 expression level and TL using patient tumor biopsies to identify radioresistant patients who could benefit from carbon hadrontherapy. 相似文献
928.
Delphine Martiny Alain Visscher Boudewijn Catry Sonia Chatellier Olivier Vandenberg 《Journal of microbiological methods》2013
Growth conditions – including growth medium and incubation temperature – may influence the identification of Campylobacter by MALDI-TOF MS. 相似文献
929.
Many species of phytoplankton are susceptible to parasitism by fungi from the phylum Chytridiomycota (i.e. chytrids). However, few studies have reported the effects of fungal parasites on filamentous cyanobacterial blooms. To investigate the missing components of bloom ecosystems, we examined an entire field bloom of the cyanobacterium Anabaena macrospora for evidence of chytrid infection in a productive freshwater lake, using a high resolution sampling strategy. A. macrospora was infected by two species of the genus Rhizosiphon which have similar life cycles but differed in their infective regimes depending on the cellular niches offered by their host. R. crassum infected both vegetative cells and akinetes while R. akinetum infected only akinetes. A tentative reconstruction of the developmental stages suggested that the life cycle of R. crassum was completed in about 3 days. The infection affected 6% of total cells (and 4% of akinètes), spread over a maximum of 17% of the filaments of cyanobacteria, in which 60% of the cells could be parasitized. Furthermore, chytrids may reduce the length of filaments of Anabaena macrospora significantly by “mechanistic fragmentation” following infection. All these results suggest that chytrid parasitism is one of the driving factors involved in the decline of a cyanobacteria blooms, by direct mortality of parasitized cells and indirectly by the mechanistic fragmentation, which could weaken the resistance of A. macrospora to grazing. 相似文献
930.
Federica Defendi Delphine Charignon Arije Ghannam Remi Baroso Fran?oise Csopaki Marion Allegret-Cadet Denise Ponard Bertrand Favier Sven Cichon Brigitte Nicolie Olivier Fain Ludovic Martin Christian Drouet 《PloS one》2013,8(8)