全文获取类型
收费全文 | 345篇 |
免费 | 27篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 10篇 |
2021年 | 22篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 15篇 |
2017年 | 13篇 |
2016年 | 15篇 |
2015年 | 14篇 |
2014年 | 17篇 |
2013年 | 25篇 |
2012年 | 50篇 |
2011年 | 40篇 |
2010年 | 16篇 |
2009年 | 17篇 |
2008年 | 20篇 |
2007年 | 23篇 |
2006年 | 16篇 |
2005年 | 12篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 8篇 |
2001年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
排序方式: 共有372条查询结果,搜索用时 15 毫秒
351.
Coordination numbers of alkali metal ions in aqueous solutions 总被引:2,自引:0,他引:2
352.
Alterations in both cell-cell and cell-matrix interactions are associated with the activation of endothelial cells that initiate angiogenesis. Cell-matrix interactions are affected by changes in both cell surface receptors for matrix proteins and the composition of ECM. One of the molecular mechanisms involved in changes in these components is the action of neutral proteinases, particularly matrix metalloproteinases. To understand the involvement of MMPs in angiogenic processes, the in vitro model of human umbilical vein endothelial cells in culture was used. Zymography and ELISA showed that, as cell-cell contact and network-like structures were formed, there was down regulation of MMP-2 and MMP-9 associated with high levels of their endogenous inhibitors TIMP-1 and TIMP-2. On treatment with aspirin, which inhibited the cell-cell contact and network-like structure formation, there was no down regulation of MMPs and cells continued to produce MMP-2 and MMP-9. These results indicate a temporal relationship between MMP-2 and MMP-9 production by endothelial cells and the onset of angiogenic event. 相似文献
353.
Noor M. Shaik Manish Arha A. Nookaraju Sushim K. Gupta Sameer Srivastava Arun K. Yadav Pallavi S. Kulkarni O. U. Abhilash Rishi K. Vishwakarma Somesh Singh Rajeshri Tatkare Kannan Chinnathambi Shuban K. Rawal Bashir M. Khan 《Physiology and Molecular Biology of Plants》2009,15(4):311-318
Leucaena leucocephala is a fast growing multipurpose legume tree used for forage, leaf manure, paper and pulp. Lignin in Leucaena pulp adversely influences the quality of paper produced. Developing transgenic Leucaena with altered lignin by genetic engineering demands an optimized regeneration system. The present study deals with optimization of regeneration system for L. leucocephala cv. K636. Multiple shoot induction from the cotyledonary nodes of L. leucocephala was studied in response to cytokinins, thidiazuron (TDZ) and N6-benzyladenine (BA) supplemented in half strength MS (½-MS) medium and also their effect on in vitro rooting of the regenerated shoots. Multiple shoots were induced from cotyledonary nodes at varied frequencies depending on the type and concentration of cytokinin used in the medium. TDZ was found to induce more number of shoots per explant than BA, with a maximum of 7 shoots at an optimum concentration of 0.23 µM. Further increase in TDZ concentration resulted in reduced shoot length and fasciation of the shoots. Liquid pulse treatment of the explants with TDZ did not improve the shoot production further but improved the subsequent rooting of the shoots that regenerated. Regenerated shoots successfully rooted on ½-MS medium supplemented with 0.54 µM α-naphthaleneacetic acid (NAA). Rooted shoots of Leucaena were transferred to coco-peat and hardened plantlets showed ≥ 90 % establishment in the green house.Key words: Cotyledonary nodes, Multiple shoot induction, Pulse treatment, TDZ 相似文献
354.
Chris P. Verschoor Sameer D. Pant Flavio S. Schenkel Bhawani S. Sharma Niel A. Karrow 《Mammalian genome》2009,20(7):447-454
Altering the balance between pro- and anti-inflammatory responses can influence an animal’s susceptibility to acute or chronic
inflammatory disease; bovine mastitis is no exception. Genetic variation in the form of single nucleotide polymorphisms (SNPs)
may alter the function and expression of genes that regulate inflammation, making them important candidates for defining an
animal’s risk of developing acute or chronic mastitis. The objective of the present study was to identify SNPs in genes that
regulate anti-inflammatory responses and test their association with estimated breeding values (EBVs) for somatic cell score
(SCS), a trait highly correlated with the incidence of mastitis. These genes included bovine interleukin-10 (IL-10) and its
receptor (IL-10R), and transforming growth factor β1 (TGF-β1) and its receptor (TGF-βR). Sequencing-pooled DNA allowed for
the identification of SNPs in IL-10 (n = 2), IL-10Rα (n = 6) and β (n = 2), and TGF-β1 (n = 1). These SNPs were subsequently genotyped in a cohort of Holstein (n = 500), Jersey (n = 83), and Guernsey (n = 50) bulls. Linear regression analysis identified significant SNP effects for IL-10Rα 1185C>T with SCS. Haplotype IL-10Rα
AAT showed a significant effect on increasing SCS compared to the most common haplotype. The results presented here indicate
that SNPs in IL-10Rα may contribute to variation in the SCS of dairy cattle. Although functional studies are necessary to
ascertain whether these SNPs are causal polymorphisms or merely in linkage with the true causal SNP(s), a selection program
incorporating these markers could have a beneficial influence on the average SCS and productivity of a dairy herd. 相似文献
355.
356.
357.
Samer Salah Walid Naser Omar Jaber Yacob Saleh Rawan Mustafa Ramiz Abuhijlih Fawzi Abuhijla Taleb Ismaeel Sameer Yaser Iyad Sultan Nour Mustafa Abdelghani Tbakhi 《Reports of Practical Oncology and Radiotherapy》2022,27(5):759
BackgroundThere remains an unmet need to identify molecular biomarkers in Ewing sarcoma (ES). We sought to assess the influence of the O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation on response and progression-free survival (PFS) following initiation of irinotecan and temozolomide (IT), PFS following initiation of vincristine, doxorubicin, and cyclophosphamide alternating with ifosfamide and etoposide (VDC-IE), and overall survival (OS).Materials and methodsData of advanced ES patients, treated with IT were retrospectively collected. Patients were required to have progression after prior VDC-IE. MGMT promoter methylation was assessed on non-decalcified Formalin-fixed paraffin embedded (FFPE) tissue using methylation sensitive restriction enzyme-quantitative PCR (MSRE-qPCR). Survival was estimated by the Kaplan-Meier method.ResultsA total of 20 ES patients underwent MGMT promoter methylation testing, and were eligible for analysis. Five patients (25%) had methylated MGMT, whereas the remaining (15; 75%) had unmethylated promoter. Five (25%) had objective response to IT, with no observed difference by promoter methylation (p = 0.76). Median PFS from initiation of IT for methylated vs. unmethylated MGMT patients was 4.9 and 1.2 months, respectively, p = 0.69. Median PFS from date of initiation of VDC-IE was significantly superior in the methylated group; 27.8 vs. 8.6 months, p = 0.034. Median OS was superior but not statistically significant in the methylated group.ConclusionMGMT-promoter methylation did not correlate with clinical activity or outcomes following the IT regimen for advanced ES. However, methylated MGMT predicted significantly superior PFS following initiation of the standard VDC-IE protocol. 相似文献
358.
Riyaz A. Mir Aditya Bele Sameer Mirza Shashank Srivastava Appolinaire A. Olou Shalis A. Ammons Jun Hyun Kim Channabasavaiah B. Gurumurthy Fang Qiu Hamid Band Vimla Band 《Molecular and cellular biology》2016,36(6):886-899
Ecdysoneless (ECD) is an evolutionarily conserved protein whose germ line deletion is embryonic lethal. Deletion of Ecd in cells causes cell cycle arrest, which is rescued by exogenous ECD, demonstrating a requirement of ECD for normal mammalian cell cycle progression. However, the exact mechanism by which ECD regulates cell cycle is unknown. Here, we demonstrate that ECD protein levels and subcellular localization are invariant during cell cycle progression, suggesting a potential role of posttranslational modifications or protein-protein interactions. Since phosphorylated ECD was recently shown to interact with the PIH1D1 adaptor component of the R2TP cochaperone complex, we examined the requirement of ECD phosphorylation in cell cycle progression. Notably, phosphorylation-deficient ECD mutants that failed to bind to PIH1D1 in vitro fully retained the ability to interact with the R2TP complex and yet exhibited a reduced ability to rescue Ecd-deficient cells from cell cycle arrest. Biochemical analyses demonstrated an additional phosphorylation-independent interaction of ECD with the RUVBL1 component of the R2TP complex, and this interaction is essential for ECD''s cell cycle progression function. These studies demonstrate that interaction of ECD with RUVBL1, and its CK2-mediated phosphorylation, independent of its interaction with PIH1D1, are important for its cell cycle regulatory function. 相似文献
359.
Arguably, 2020 was the year of high-accuracy protein structure predictions, with AlphaFold 2.0 achieving previously unseen accuracy in the Critical Assessment of Protein Structure Prediction (CASP). In 2021, DeepMind and EMBL-EBI developed the AlphaFold Protein Structure Database to make an unprecedented number of reliable protein structure predictions easily accessible to the broad scientific community. We provide a brief overview and describe the latest developments in the AlphaFold database. We highlight how the fields of data services, bioinformatics, structural biology, and drug discovery are directly affected by the influx of protein structure data. We also show examples of cutting-edge research that took advantage of the AlphaFold database. It is apparent that connections between various fields through protein structures are now possible, but the amount of data poses new challenges. Finally, we give an outlook regarding the future direction of the database, both in terms of data sets and new functionalities. 相似文献
360.