全文获取类型
收费全文 | 11435篇 |
免费 | 2004篇 |
国内免费 | 6509篇 |
出版年
2024年 | 54篇 |
2023年 | 428篇 |
2022年 | 703篇 |
2021年 | 741篇 |
2020年 | 774篇 |
2019年 | 868篇 |
2018年 | 606篇 |
2017年 | 548篇 |
2016年 | 604篇 |
2015年 | 782篇 |
2014年 | 1066篇 |
2013年 | 927篇 |
2012年 | 1269篇 |
2011年 | 1245篇 |
2010年 | 1016篇 |
2009年 | 1037篇 |
2008年 | 1087篇 |
2007年 | 1034篇 |
2006年 | 918篇 |
2005年 | 806篇 |
2004年 | 626篇 |
2003年 | 542篇 |
2002年 | 487篇 |
2001年 | 468篇 |
2000年 | 377篇 |
1999年 | 239篇 |
1998年 | 111篇 |
1997年 | 68篇 |
1996年 | 52篇 |
1995年 | 76篇 |
1994年 | 45篇 |
1993年 | 38篇 |
1992年 | 38篇 |
1991年 | 30篇 |
1990年 | 23篇 |
1989年 | 28篇 |
1988年 | 24篇 |
1987年 | 28篇 |
1986年 | 23篇 |
1985年 | 24篇 |
1984年 | 18篇 |
1983年 | 14篇 |
1982年 | 23篇 |
1981年 | 10篇 |
1979年 | 2篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1950年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Cheng Qian MD Danqi Chang MD Hang Li MD Yanggan Wang 《Journal of cellular biochemistry》2019,120(5):7771-7777
Heart failure (HF) remains a common complication after acute ST-segment elevation myocardial infarction (STEMI). Here, we aim to identify critical genes related to the developed HF in patients with STEMI using bioinformatics analysis. The microarray data of GSE59867, including peripheral blood samples from nine patients with post-infarct HF and eight patients without post-infarct HF, were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) between HF and non-HF groups were screened by LIMMA package. Functional enrichment analyses of DEGs were conducted, followed by construction of a protein-protein interaction (PPI) network. The dynamic messenger RNA (mRNA) level of the hub genes during the follow-up was analyzed to further elucidate their role in HF development. A total of 58 upregulated and 75 downregulated DEGs were screen out. They were mainly enriched in biological processes about inflammatory response, extracellular matrix organization, response to cAMP, immune response, and positive regulation of cytosolic calcium ion concentration. Pathway analysis revealed that the DEGs were also involved in hematopoietic cell lineage, pathways in cancer, and extracellular matrix-receptor interaction. In the PPI network consisting of 58 nodes and 72 interactions, CXCL8 (degree = 15), THBS1 (degree = 8), FOS (degree = 7), and ITGA2B (degree = 6) were identified as the hub genes. In the comparison of patients with and without post-infarct HF, the mRNA level of these hub genes were all higher within 30 days but reached similar at 6 months after STEMI. In conclusion, CXCL8, THBS1, FOS, and ITGA2B may play important roles in the development of HF after acute STEMI. 相似文献
5.
【目的】从兰州唐古特白刺根际分离得到对植物有潜在促生效果的功能微生物,为研发相关菌种制剂的研究奠定基础。【方法】通过平板划线法从其根际分离纯化出6株细菌,并对菌株进行形态特征观察、革兰氏染色等一系列生理生化试验。用藜麦检测各菌株的促生功能,并对具有优良促生作用的1个菌株16S rRNA基因进行分子鉴定及基因草图绘制。【结果】根据生化鉴定结果,6株细菌分别属于不动杆菌属(Acinetobacter)、土壤杆菌属(Agrobacterium)、类芽孢杆菌属(Paenibacillus)、芽孢杆菌属(Bacillus)、鞘氨醇单胞菌属(Sphingomonas)和假单胞菌属(Pseudomonas)。其中,16S rRNA基因鉴定BC4属于肠杆菌属(Enterobacter),具有较好的促生效果。【结论】BC4具有较好的促生效果,为兰州唐古特白刺菌种资源的开发和利用提供了一定的理论依据。 相似文献
6.
7.
8.
9.
10.
Ting‐Hang Liu Chia‐Lin Chyan Feng‐Yin Li Ying‐Jie Chen Jason T. C. Tzen 《Biotechnology progress》2011,27(6):1760-1767
It has been demonstrated that caleosin alone is sufficient to stabilize artificial oil bodies. A series of recombinant caleosins, mutated with 3, 5, 8, 11, 13, 15, and 17 extra Lys residues and over‐expressed in Escherichia coli, were used as carrier proteins to render biotin as a hapten on the surface of artificial oil bodies for antibody production. Biotinylation levels of the recombinant caleosins were step‐wisely elevated as the number of extra Lys residues increased, and the biotinylated Lys residues were identified by mass spectrometric analysis. Polyclonal antibodies against biotin were successfully generated in rats injected with artificial oil bodies constituted with each of the biotinylated caleosins. Moreover, those generated via the biotinylated caleosins with eight or more extra Lys residues no longer recognized caleosin. It appears that engineered Lys‐rich caleosins are suitable carrier proteins for the production of antibodies against small molecules. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011 相似文献