全文获取类型
收费全文 | 2622篇 |
免费 | 248篇 |
国内免费 | 1篇 |
专业分类
2871篇 |
出版年
2023年 | 16篇 |
2022年 | 34篇 |
2021年 | 104篇 |
2020年 | 47篇 |
2019年 | 66篇 |
2018年 | 67篇 |
2017年 | 57篇 |
2016年 | 88篇 |
2015年 | 143篇 |
2014年 | 173篇 |
2013年 | 210篇 |
2012年 | 238篇 |
2011年 | 224篇 |
2010年 | 125篇 |
2009年 | 135篇 |
2008年 | 166篇 |
2007年 | 151篇 |
2006年 | 125篇 |
2005年 | 114篇 |
2004年 | 66篇 |
2003年 | 77篇 |
2002年 | 71篇 |
2001年 | 38篇 |
2000年 | 30篇 |
1999年 | 29篇 |
1998年 | 19篇 |
1997年 | 15篇 |
1996年 | 11篇 |
1995年 | 19篇 |
1994年 | 18篇 |
1993年 | 16篇 |
1992年 | 13篇 |
1991年 | 16篇 |
1990年 | 20篇 |
1989年 | 13篇 |
1988年 | 10篇 |
1987年 | 5篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1974年 | 5篇 |
1973年 | 11篇 |
1972年 | 4篇 |
1970年 | 4篇 |
1969年 | 9篇 |
1968年 | 4篇 |
排序方式: 共有2871条查询结果,搜索用时 0 毫秒
91.
Claire Périlleux Alexandra Pieltain Guillaume Jacquemin Frédéric Bouché Nathalie Detry Maria D'Aloia Laura Thiry Pierre Aljochim Martin Delansnay Anne‐Sophie Mathieu Stanley Lutts Pierre Tocquin 《The Plant journal : for cell and molecular biology》2013,75(3):390-402
Root chicory (Cichorium intybus var. sativum) is a biennial crop, but is harvested to obtain root inulin at the end of the first growing season before flowering. However, cold temperatures may vernalize seeds or plantlets, leading to incidental early flowering, and hence understanding the molecular basis of vernalization is important. A MADS box sequence was isolated by RT‐PCR and named FLC‐LIKE1 (CiFL1) because of its phylogenetic positioning within the same clade as the floral repressor Arabidopsis FLOWERING LOCUS C (AtFLC). Moreover, over‐expression of CiFL1 in Arabidopsis caused late flowering and prevented up‐regulation of the AtFLC target FLOWERING LOCUS T by photoperiod, suggesting functional conservation between root chicory and Arabidopsis. Like AtFLC in Arabidopsis, CiFL1 was repressed during vernalization of seeds or plantlets of chicory, but repression of CiFL1 was unstable when the post‐vernalization temperature was favorable to flowering and when it de‐vernalized the plants. This instability of CiFL1 repression may be linked to the bienniality of root chicory compared with the annual lifecycle of Arabidopsis. However, re‐activation of AtFLC was also observed in Arabidopsis when a high temperature treatment was used straight after seed vernalization, eliminating the promotive effect of cold on flowering. Cold‐induced down‐regulation of a MADS box floral repressor and its re‐activation by high temperature thus appear to be conserved features of the vernalization and de‐vernalization responses in distant species. 相似文献
92.
Guillaume Sarrabayrouse Christine Pich Rapha?l Moriez Virginie Armand-Labit Philippe Rochaix Gilles Favre Anne-Fran?oise Tilkin-Mariamé 《PloS one》2010,5(2)
Background
Suboptimal activation of T lymphocytes by melanoma cells is often due to the defective expression of class I major histocompatibility antigens (MHC-I) and costimulatory molecules. We have previously shown that geranylgeranyl transferase inhibition (done with GGTI-298) stimulates anti-melanoma immune response through MHC-I and costimulatory molecule expression in the B16F10 murine model [1].Methodology/Principal Findings
In this study, it is shown that vaccination with mIFN-gand GGTI-298 pretreated B16F10 cells induces a protection against untreated tumor growth and pulmonary metastases implantation. Furthermore, using a human melanoma model (LB1319-MEL), we demonstrated that in vitro treatment with hIFN-γ and GGTI-298 led to the up regulation of MHC-I and a costimulatory molecule CD86 and down regulation of an inhibitory molecule PD-1L. Co-culture experiments with peripheral blood mononuclear cells (PBMC) revealed that modifications induced by hIFN-γ and GGTI-298 on the selected melanoma cells, enables the stimulation of lymphocytes from HLA compatible healthy donors. Indeed, as compared with untreated melanoma cells, pretreatment with hIFN-γ and GGTI-298 together rendered the melanoma cells more efficient at inducing the: i) activation of CD8 T lymphocytes (CD8+/CD69+); ii) proliferation of tumor-specific CD8 T cells (MelanA-MART1/TCR+); iii) secretion of hIFN-γ; and iv) anti-melanoma specific cytotoxic cells.Conclusions/Significance
These data indicate that pharmacological treatment of melanoma cell lines with IFN-γ and GGTI-298 stimulates their immunogenicity and could be a novel approach to produce tumor cells suitable for vaccination and for stimulation of anti-melanoma effector cells. 相似文献93.
Identification of ciliary and ciliopathy genes in Caenorhabditis elegans through comparative genomics 总被引:2,自引:0,他引:2
94.
ádám Z. Lendvai Mathieu Giraudeau Veronika Bókony Frédéric Angelier Olivier Chastel 《Biology letters》2015,11(7)
A crucial problem for every organism is how to allocate energy between competing life-history components. The optimal allocation decision is often state-dependent and mediated by hormones. Here, we investigated how age, a major state variable affects individuals'' hormonal response to a standardized stressor: a trait that may reflect allocation between self-maintenance and reproduction. We caught free-living house sparrows and measured their hormonal (corticosterone) response to capture stress in consecutive years. Using a long-term ringing dataset, we determined the age of the birds, and we partitioned the variation into within- and among-individual age components to investigate the effects of plasticity versus selection or gene flow, respectively, on the stress response. We found large among-individual variation in the birds'' hormone profiles, but overall, birds responded less strongly to capture stress as they grew older. These results suggest that stress responsiveness is a plastic trait that may vary within individuals in an adaptive manner, and natural selection may act on the reaction norms producing optimal phenotypic response in the actual environment and life-history stage. 相似文献
95.
Fe homeostasis in plant cells: Does nicotianamine play multiple roles in the regulation of cytoplasmic Fe concentration? 总被引:14,自引:0,他引:14
Axel Pich Renate Manteuffel Stefan Hillmer Günter Scholz Wolfgang Schmidt 《Planta》2001,213(6):967-976
The cellular and intracellular localization of the non-proteogenic amino acid nicotianamine (NA) in leaves and root elongation zones was immunochemically investigated in pea (Pisum sativum L.) and tomato (Lycopersicon esculentum Mill.) plants grown under various iron regimes and in three mutants defective in the regulation of iron uptake. Strongest immunostaining was observed in the over-accumulating pea mutants brz and dgl, and in iron-loaded wild-type plants. Fe concentration and NA level paralleled staining intensity, indicating that NA synthesis is induced by high iron availability. While label was mainly present in the cytoplasm under normal (10 microM) Fe supply and under Fe deprivation, most of the labeling was present in the vacuole in iron-loaded plants. This pattern resembled the distribution of NA in Fe over-accumulating mutants, indicating the possible importance of vacuolar sequestration in the detoxification of excess Fe. Based on the dependence of the cellular distribution of NA on the iron nutritional status of the plant, a possible role of NA in buffering free Fe in root and leaf cells was inferred. We show here for the first time that the NA concentration is increased in response to iron overload, indicating that, besides other classes of intracellular metal-binding ligands, NA may play an essential role in iron tolerance. 相似文献
96.
97.
98.
99.
Farshid Bahrami Mathieu Maisonneuve Michel Meunier Arthur O. Montazeri Yujin Kim Nazir P. Kherani J. Stewart Aitchison Mo Mojahedi 《Journal of biophotonics》2017,10(2):271-277
A plasmon waveguide resonance (PWR) sensor is proposed for studying the interaction between gold nanoparticles and proteins. The ability of the PWR sensor to operate in both TM and TE Polarizations, i.e. its polarization diversity, facilitates the simultaneous spectroscopy of the nanoparticles surface reactions using both polarizations. The response of each polarization to streptavidin‐biotin binding at the surface of gold nanoparticles is investigated in real time. Finally, using the principles of multimode spectroscopy, the nanoparticle's surface reactions are decoupled from the bulk solution refractive index variations.
100.