首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   498篇
  免费   30篇
  2023年   2篇
  2022年   2篇
  2021年   6篇
  2020年   6篇
  2019年   8篇
  2018年   8篇
  2017年   9篇
  2016年   11篇
  2015年   28篇
  2014年   40篇
  2013年   29篇
  2012年   39篇
  2011年   52篇
  2010年   30篇
  2009年   26篇
  2008年   29篇
  2007年   28篇
  2006年   25篇
  2005年   22篇
  2004年   30篇
  2003年   20篇
  2002年   22篇
  2001年   14篇
  2000年   8篇
  1999年   9篇
  1998年   8篇
  1997年   1篇
  1996年   2篇
  1995年   2篇
  1994年   1篇
  1993年   1篇
  1990年   3篇
  1988年   2篇
  1982年   1篇
  1981年   1篇
  1977年   2篇
  1953年   1篇
排序方式: 共有528条查询结果,搜索用时 93 毫秒
11.
As the importance of personalized therapeutics in aggressive papillary thyroid cancer (PTC) increases, accurate risk stratification is required. To develop a novel prognostic scoring system for patients with PTC (n = 455), we used mRNA expression and clinical data from The Cancer Genome Atlas. We performed variable selection using Network‐Regularized high‐dimensional Cox‐regression with gene network from pathway databases. The risk score was calculated using a linear combination of regression coefficients and mRNA expressions. The risk score and clinical variables were assessed by several survival analyses. The risk score showed high discriminatory power for the prediction of event‐free survival as well as the presence of metastasis. In multivariate analysis, the risk score and presence of metastasis were significant risk factors among the clinical variables that were examined together. In the current study, we developed a risk scoring system that will help to identify suitable therapeutic options for PTC.  相似文献   
12.
Kim HC  Jhoo WK  Kim WK  Shin EJ  Cheon MA  Shin CY  Ko KH 《Life sciences》2001,69(8):915-922
We examined the effects of a non-opioid antitussive, carbetapentane (CB) on kainic acid (KA)-induced neurotoxicity in rats. KA administration (10 mg/kg, i.p.) produced robust behavioral convulsions lasting 4 to 5 h. CB (12.5 and 25 mg/kg. i.p.) pretreatment consistently and in a dose-dependent manner reduced the KA-induced seizures, mortality, and marked loss of cells in regions CA1 and CA3 of the hippocampus. Consistently, CB pretreatment also significantly attenuated the KA-induced increase in Fos-related antigen immunoreactivity in the hippocampus. In contrast, pretreatment with the sigma-1 receptor antagonist BD1047 (1 and 2 mg/kg, i.p.) blocked, in a dose-related manner, the neuroprotection afforded by CB. These results suggest that CB provides neuroprotection against KA insult via sigma-1 receptor modulation.  相似文献   
13.
Keratinocyte growth factor (KGF) is an unusual fibroblast growth factor (FGF) family member in that its activity is largely restricted to epithelial cells, and added heparin/heparan sulfate inhibits its activity in most cell types. The effects of heparan sulfate proteoglycan (HSPG) on binding and signaling by acidic FGF (aFGF) and KGF via the KGFR were studied using surface-bound and soluble receptor isoforms expressed in wild type and mutant Chinese hamster ovary (CHO) cells lacking HSPG. Low concentrations of added heparin (1 microgram/mL) enhanced the affinity of ligand binding to surface-bound KGFR in CHO mutants, as well as ligand-stimulated MAP kinase activation and c-fos induction, but had little effect on binding or signaling in wild type CHO cells. Higher heparin concentrations inhibited KGF, but not aFGF, binding and signaling. In addition to the known interaction between HSPG and KGF, we found that the KGFR also bound heparin. The biphasic effect of heparin on KGF, but not aFGF, binding and signaling suggests that occupancy of the HSPG binding site on the KGFR may specifically inhibit KGF signaling. In contrast to events on the cell surface, added heparin was not required for high-affinity soluble KGF-KGFR interaction. These results suggest that high-affinity ligand binding is an intrinsic property of the receptor, and that the difference between the HSPG-dependent ligand binding to receptor on cell surfaces and the HSPG-independent binding to soluble receptor may be due to other molecule(s) present on cell surfaces.  相似文献   
14.
We have sequenced a cDNA clone encoding a 26-kDa ferritin subunit, which was heavy chain homologue (HCH), in fall webworm, Hyphantria cunea. The HCH cDNA was obtained from the screening of a cDNA library using a PCR product. H. cunea ferritin is composed of 221 amino acid residues and their calculated mass is 26,160 Da. The protein contains the conserved motifs for the ferroxidase center typical for heavy chains of vertebrate ferritin. The iron-responsive element sequence with a predicted stem-loop structure is present in the 5'-untranslated region of ferritin HCH mRNA. The sequence alignment of ferritin HCH shows 68.9 and 68.7% identity with Galleria mellonella HCH (26 kDa ferritin) and Manduca sexta HCH, respectively. While G type insect ferritin vertebrate light chain homologue (LCH) is distantly related to H. cunea ferritin HCH (17.2-20.8%), the Northern blot analysis revealed that H. cunea ferritin HCH was ubiquitously expressed in various tissues and all developmental stages. The ferritin expression of midgut is more responsive to iron-fed, compared to fat body in H. cunea.  相似文献   
15.
Yuk CS  Lee HK  Kim HT  Choi YK  Lee BC  Chun BH  Chung N 《Biotechnology letters》2004,26(20):1563-1568
A protein chip diagnostic kit was developed for the diagnosis of hepatitis C virus (HCV) based on the protein chip technique and the immuno-concentration method. This kit was designed for low-density protein chips and also for the availability of multiple sample screening. Applicability of the chip was evaluated using 96 blood specimens and the results were compared to results of an anti-HCV enzyme immunoassay (EIA) test. With further development, the technology associated with the development of this chip could be applied to the simultaneous detection of multiple protein-protein, protein-ligand interactions.  相似文献   
16.
For the development of safer anti-inflammatory agents, simple aromatic compounds containing propenone moiety were prepared and evaluated for their dual COX/5-LOX inhibitory activities. Among the 17 prepared compounds, most of the compounds exhibited considerable COX/5-LOX inhibitory activities. Especially compound C(15) showed the most significant dual COX/5-LOX inhibitory activity.  相似文献   
17.
The recombinant gene was amplified from the chromosomal DNA of genetically-modified (GM) soybeans and identified as epsps encoding 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) which renders glyphosate resistance. The epsps structural gene was introduced in the pET28(a) plasmid for its expression in Escherichia coli BL21(DE3). It was confirmed that the maximal productivity of the EPSPS protein was achieved when cultivating the recombinant strain in a LB broth for 2 h after supplementing 1 mM isopropylbeta-D-thiogalactopyranoside (IPTG) in a 2 h-culture broth. Since the expressed EPSPS protein was found as an insoluble form in the inclusion body, it was extracted by 6 M urea after sonication, and then purified through immobilized nickel-affinity column chromatography to isolate EPSPS having a molecular mass of 57 kDa. When incubated in simulated gastric fluid containing pepsin at pH 1.5, the purified EPSPS protein was completely digested within 1 min. In addition, the passive cutaneous anaphylaxis reaction of the purified EPSPS protein was not observed in the Sprague Dawley rat system that was administered either orally or subcutaneously. Furthermore, treatment of the EPSPS protein to the culture of the sensitized peritoneal mast cells, or unsensitized but antisera-labeled mast cells, showed neither a remarkable change in the histamine release nor a cytokine production, including interleukin-4 (IL-4) and tumor necrosis factor-alpha (TNF-alpha). Thus, it can be concluded that the EPSPS protein in the GM soybean showed no significant allergenicity in the Sprague Dawley rats.  相似文献   
18.
Jung KC  Kim NH  Park WS  Park SH  Bae Y 《FEBS letters》2003,554(3):478-484
The CD99 antigen has been implicated in various cellular processes, including apoptosis in T cells. Previously, we reported two monoclonal antibodies that recognize different epitopes of the CD99 molecule, named DN16 and YG32. In this study, we investigated the role of each CD99 epitope in T cell apoptosis. Unlike the DN16 epitope, CD99 ligation via the YG32 epitope failed to induce T cell death. Surprisingly, however, the YG32 signal enhanced Fas-mediated apoptosis in Jurkat T cells. Augmentation of Fas-mediated apoptosis by YG32 ligation was inhibited by treatment with either of the caspase inhibitors z-VAD-fmk or z-IETD-fmk, and YG32 ligation appeared to induce Fas oligomerization. These results suggest that each CD99 epitope plays a distinct role in T cell biology, especially in T cell apoptosis.  相似文献   
19.
In diagnostic pathology and immunocytochemical research, immunohistochemical techniques using the streptavidin–biotin–peroxidase system have played an extremely valuable role. This system, based on the high affinity of streptavidin for biotin, may, however, provoke false positive results because of endogenous streptavidin-binding sites in human tissues. With the advent of the antigen retrieval procedure and signal amplification method, this problem can be serious enough to cause mistakes in interpreting immunohistochemical staining results. Therefore, we examined the distribution of endogenous biotin-like molecules in various human tissues and the influence of various antigen retrieval procedures with or without signal amplification using biotinylated tyramine to reveal these biotin-like activities. We observed that endogenous biotin-like molecules were present in a wide range of tissues, and their activity was markedly enhanced by employing antigen retrieval procedures or signal amplification. Furthermore, the extent to which the activity of endogenous biotin-like activities was enhanced depended on the kinds of antigen retrieval procedures and signal amplification employed. Pressure cooking and tyramine amplification with microwave heating showed the highest activities. These results show that the antigen retrieval procedures and signal amplification with tyramine can enhance the activity of endogenous biotin or biotin-like molecules as well as antigenicity, which can be a pitfall in the interpretation of immunohistochemical data.  相似文献   
20.
Nine white-rot fungal strains were screened for biodecolourization of brilliant green, cresol red, crystal violet, congo red and orange II. Dichomitus squalens, Phlebia fascicularia and P. floridensis decolourized all of the dyes on solid agar medium and possessed better decolourization ability than Phanerochaete chrysosporium when tested in nitrogen-limited broth medium. Journal of Industrial Microbiology & Biotechnology (2002) 28, 201–203 DOI: 10.1038/sj/jim/7000222 Received 12 July 2001/ Accepted in revised form 22 October 2001  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号