全文获取类型
收费全文 | 2152篇 |
免费 | 88篇 |
专业分类
2240篇 |
出版年
2024年 | 4篇 |
2023年 | 11篇 |
2022年 | 40篇 |
2021年 | 49篇 |
2020年 | 27篇 |
2019年 | 52篇 |
2018年 | 58篇 |
2017年 | 36篇 |
2016年 | 86篇 |
2015年 | 118篇 |
2014年 | 125篇 |
2013年 | 157篇 |
2012年 | 214篇 |
2011年 | 206篇 |
2010年 | 130篇 |
2009年 | 107篇 |
2008年 | 163篇 |
2007年 | 145篇 |
2006年 | 90篇 |
2005年 | 94篇 |
2004年 | 78篇 |
2003年 | 65篇 |
2002年 | 42篇 |
2001年 | 28篇 |
2000年 | 29篇 |
1999年 | 25篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 5篇 |
1992年 | 9篇 |
1991年 | 4篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1967年 | 3篇 |
1965年 | 1篇 |
排序方式: 共有2240条查询结果,搜索用时 15 毫秒
951.
Hydrobiologia - Anthropogenic habitat alteration can rapidly disturb native fish species by hybridization with introduced species. In Korea, the construction of water conduits has unilaterally... 相似文献
952.
Soh-Hyun Lee Sun-Ok Ha Ho-Jin Koh KilSoo Kim Seon-Min Jeon Myung-Sook Choi Oh-Shin Kwon Tae-Lin Huh 《Molecules and cells》2010,29(2):203-208
Hyperglycemia-induced oxidative stress is widely recognized as a key mediator in the pathogenesis of diabetic nephropathy,
a complication of diabetes. We found that both expression and enzymatic activity of cytosolic NADP+-dependent isocitrate dehydrogenase (IDPc) were upregulated in the renal cortexes of diabetic rats and mice. Similarly, IDPc
was induced in murine renal proximal tubular OK cells by high hyperglycemia, while it was abrogated by co-treatment with the
antioxidant N-Acetyl-Cysteine (NAC). In OK cells, increased expression of IDPc by stable transfection prevented hyperglycemia-mediated
reactive oxygen species (ROS) production, subsequent cellular oxidative stress and extracellular matrix accumulation, whereas
these processes were all stimulated by decreased IDPc expression. In addition, production of NADPH and GSH in the cytosol
was positively correlated with the expression level of IDPc in OK cells. These results together indicate that upregulation
of IDPc in response to hyperglycemia might play an essential role in preventing the progression of diabetic nephropathy, which
is accompanied by ROS-induced cellular damage and fibrosis, by providing NADPH, the reducing equivalent needed for recycling
reduced glutathione and low molecular weight antioxidant thiol proteins. 相似文献
953.
Jaejoon Jung Hyoju Seo Se Hee Lee Che Ok Jeon Woojun Park 《Applied microbiology and biotechnology》2013,97(10):4511-4521
The effects of malachite green (MG) on the bacterial community in Antarctic soil were assessed. Culture-independent community analysis using 16S rRNA gene pyrosequencing showed that, in the presence of MG, the relative abundance of Pseudomonas dramatically increased from 2.2 % to 36.6 % (16.6-fold), and Pseudomonas became the predominant genus. The reduction in bacterial biodiversity was demonstrated by diversity indices and rarefaction curves. MG-degrading Pseudomonas sp. MGO was isolated from Antarctic soil. MG tolerance and decolorization activity were confirmed by growth, spectrophotometric, high-performance liquid chromatography, and thin-layer chromatography analyses in high MG concentrations. Our data showed that the decolorization process occurred via biodegradation, while biosorption also occurred after some time during the fed-batch decolorization process. Significant inductions in laccase, nicotinamide adenine dinucleotide–2,6 dichlorophenol indophenol reductase, and MG reductase activities suggested their involvement in the decolorization process. We also showed that the high tolerance of strain MGO to toxic MG might be mediated by upregulation of oxidative stress defense systems such as superoxide dismutase and protease. Collectively, these results demonstrated the response of the Antarctic soil bacterial community to MG and provided insight into the molecular mechanism of MG-tolerant Pseudomonas strains isolated from Antarctic soil. 相似文献
954.
Electroconvulsive shock increases the phosphorylation of Pyk2 in the rat hippocampus 总被引:2,自引:0,他引:2
Jeon SH Oh SW Kang UG Ahn YM Bae CD Park JB Kim YS 《Biochemical and biophysical research communications》2001,282(4):1026-1030
Recently we reported the activation MAPKs, MEK, and Rafs by electroconvulsive shock (ECS) in the rat hippocampus. However, the upstream pathways for the activation of Raf-MEK-MAPK cascade after ECS have not been studied yet. Since the proline-rich tyrosine kinase 2 (Pyk2) and Src were reported to be involved in the activation of the MAPKs in neuronal cells, we examined tyrosine phosphorylation and activation of Pyk2 in the rat hippocampus after ECS. ECS transiently increased the phosphorylation of Pyk2 at multiple tyrosine residues (Tyr-402, Tyr-580, and Tyr-881). The phosphorylations reached the peak at 1 min and returned to basal level by 10 min after ECS. At 1 min after ECS, the binding of Pyk2 to Src and Grb2, and of Grb2 to Ras increased. These results suggested that ECS activates Pyk2, which then transmits the signal to MAPK cascade via Src, Grb2, and Ras in the rat hippocampus. 相似文献
955.
Soo Hyung Eo Woo-Shin Lee Byeong-Ju Lee Byung June Ko Jong U. Kim Jong Hoon Jeon 《Genes & genomics.》2016,38(4):351-357
Understanding the impacts of forest management practices on genetic diversity is essential for effective animal management and conservation. We characterized novel microsatellite loci in the Ussuri white-toothed shrew (Crocidura lasiura Dobson, 1890) to test the impacts of anthropogenic thinning of forest trees on the shrew populations and their genetic diversity. Using Ion Torrent sequencing technology, we characterized 611 potential microsatellite markers with complete di- to tetra-nucleotide motifs, identifying nine polymorphic loci. The observed and expected heterozygosities across the nine loci were 0.526 and 0.527, respectively. Mean allelic diversity was 5.2 alleles per locus, with the mean polymorphism information content at 0.498. In comparison among shrew populations, which inhabited in the forests thinned in 2004 (CLA; n = 10), 2008 (CLB; n = 9) and 2014 (CLC; n = 3), the observed heterozygosities are similar among the three populations (0.525 at CLA, 0.532 at CLB and 0.519 at CLC), whereas the expected heterozygosities were much lower in population of CLC (0.377) than that of CLA (0.509) and CLB (0.533). The small sample size at CLC limited effective comparison and evaluation of the impact of forest thinning on genetic diversity in this shrew population. Future application of the species-specific microsatellite markers described here to a larger sample size would be valuable in estimating the ecological parameters of shrew populations associated with existing forest management practices. 相似文献
956.
Jeon Jong-Min Song Hun-Suk Lee Doo-Geun Hong Ju Won Hong Yoon Gi Moon Yu-Mi Bhatia Shashi Kant Yoon Jeong-Jun Kim Wooseong Yang Yung-Hun 《Bioprocess and biosystems engineering》2018,41(8):1195-1204
Bioprocess and Biosystems Engineering - n-Butanol is considered as the next-generation biofuel, because its physiochemical properties are very similar to fossil fuels and it could be produced by... 相似文献
957.
Purpose
The objective of the present study was to conduct a systematic review and meta-analysis of published literature investigating the survivin expression and its effects on bladder cancer prognosis.Materials and Methods
We carefully searched online Pubmed, Cochrane Library and SCOPUS database from August 1997 to May 2013.Results
A total of 14 articles met the eligibility criteria for this systematic review. The eligible studies included a total of 2,165 patients with a median number of 155 patients per study (range: 17–726). Of the 14 studies, nine evaluated immunohistochemistry in formalin-fixed paraffin-embedded tissue blocks. In non-muscle invasive bladder tumor, the pooled hazard ratio (HR) was statistically significant for recurrence-free survival (pooled HR, 1.81; 95% confidence interval [CI], 1.30–2.52), progression-free survival (pooled HR, 2.12; 95% CI, 1.60–2.82), cancer-specific survival (pooled HR, 2.01; 95% CI, 1.32–3.06), and overall survival (pooled HR, 1.53; 95% CI, 1.02–2.29). The overall HRs by survivin status were robust across advanced stages. When only adjusted survival data were included, statistically significant differences were identified for all survival subgroup analyses. There was no between-study heterogeneity in the effect of survivin status on the majority of meta-analyses. There was no clear evidence of publication bias in this meta-analysis.Conclusions
Survivin expression indicates worse prognosis in patients with bladder cancer but the results should be interpreted with caution. It is necessary that better-designed studies with standardized assays need to provide a better conclusion about the relationship between survivin expression and the outcome of patients with bladder cancer. 相似文献958.
Posner GH Crawford KR Yang HW Kahraman M Jeon HB Li H Lee JK Suh BC Hatcher MA Labonte T Usera A Dolan PM Kensler TW Peleg S Jones G Zhang A Korczak B Saha U Chuang SS 《The Journal of steroid biochemistry and molecular biology》2004,(1-5):5-12
The new 24-phenylsulfone 4a, a low-calcemic analog of the natural hormone 1alpha,25-dihydroxyvitamin D(3), is a potent (IC(50) = 28nM) and highly selective inhibitor of the human 24-hydroxylase enzyme CYP24. 相似文献
959.
Yoon JW Jeon EJ Jung IH Min MJ Lee HY Kim MJ Baek JS Lee HS Park CS Oh S Park KH Moon TW 《Bioscience, biotechnology, and biochemistry》2003,67(3):525-531
This study was done to modify erythritol to change its physicochemical and sensory properties. Erythritol, a four-carbon sugar alcohol, was transglycosylated by Bacillus stearothermophilus maltogenic amylase with maltotriose as a donor molecule. The presence of various transglycosylation products of erythritol was confirmed by TLC and high performance ion exchange chromatography (HPIC). The major transfer product was purified by gel filtration chromatography on Bio-Gel P-2. Examination by LC-MS, matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF-MS), and 13C NMR showed that the major transfer product was maltosyl-erythritol. Results of 13C NMR of maltosyl-erythritol suggested that linkage was formed between the C1 carbon of glucose unit in maltose and either one of the two carbon atoms of the terminal hydroxyl groups of erythritol, so that a mixture of 1-O- and 4-O-alpha-maltosyl-erythritol was produced. The sweetness of maltosyl-erythritol was about 40% that of sucrose, and its negative sensory properties were less than those of erythritol. 相似文献
960.
Dudley H. McNitt Soo Jeon Choi Jessica L. Allen River A. Hames Scott A. Weed Livingston Van De Water Rita Berisio Slawomir Lukomski 《Molecular microbiology》2019,112(3):800-819
The human‐adapted pathogen group A Streptococcus (GAS) utilizes wounds as portals of entry into host tissue, wherein surface adhesins interact with the extracellular matrix, enabling bacterial colonization. The streptococcal collagen‐like protein 1 (Scl1) is a major adhesin of GAS that selectively binds to two fibronectin type III (FnIII) repeats within cellular fibronectin, specifically the alternatively spliced extra domains A and B, and the FnIII repeats within tenascin‐C. Binding to FnIII repeats was mediated through conserved structural determinants present within the Scl1 globular domain and facilitated GAS adherence and biofilm formation. Isoforms of cellular fibronectin that contain extra domains A and B, as well as tenascin‐C, are present for several days in the wound extracellular matrix. Scl1‐FnIII binding is therefore an example of GAS adaptation to the host's wound environment. Similarly, cellular fibronectin isoforms and tenascin‐C are present in the tumor microenvironment. Consistent with this, FnIII repeats mediate GAS attachment to and enhancement of biofilm formation on matrices deposited by cancer‐associated fibroblasts and osteosarcoma cells. These data collectively support the premise for utilization of the Scl1‐FnIII interaction as a novel method of anti‐neoplastic targeting in the tumor microenvironment. 相似文献