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   2260篇
  免费   173篇
  国内免费   2篇
  2024年   3篇
  2023年   6篇
  2022年   27篇
  2021年   34篇
  2020年   21篇
  2019年   44篇
  2018年   57篇
  2017年   59篇
  2016年   108篇
  2015年   153篇
  2014年   154篇
  2013年   166篇
  2012年   211篇
  2011年   202篇
  2010年   141篇
  2009年   121篇
  2008年   150篇
  2007年   141篇
  2006年   118篇
  2005年   108篇
  2004年   135篇
  2003年   87篇
  2002年   65篇
  2001年   18篇
  2000年   18篇
  1999年   23篇
  1998年   11篇
  1997年   11篇
  1996年   3篇
  1995年   2篇
  1994年   2篇
  1993年   5篇
  1992年   4篇
  1991年   4篇
  1990年   2篇
  1989年   4篇
  1988年   1篇
  1987年   1篇
  1985年   3篇
  1984年   1篇
  1983年   1篇
  1975年   1篇
  1973年   1篇
  1971年   1篇
  1969年   1篇
  1968年   2篇
  1967年   1篇
  1857年   1篇
  1856年   2篇
排序方式: 共有2435条查询结果,搜索用时 15 毫秒
61.
5-Hydroxytryptamine (5-HT) induces proliferation of cancer cells and vascular cells. In addition to 5-HT production by several cancer cells including gastrointestinal and breast cancer, a significant level of 5-HT is released from activated platelets in the thrombotic environment of tumors, suggesting that inhibition of 5-HT signaling may constitute a new target for antiangiogenic anticancer drug discovery. In the current study we clearly demonstrate that 5-HT-induced angiogenesis was mediated through the 5-HT1 receptor-linked Gβγ/Src/PI3K pathway, but not through the MAPK/ERK/p38 pathway. In addition, 5-HT induced production of NADPH oxidase (NOX)-derived reactive oxygen species (ROS). In an effort to develop new molecularly targeted anticancer agents against 5-HT action in tumor growth, we demonstrate that BJ-1108, a derivative of 6-amino-2,4,5-trimethylpyridin-3-ol, significantly inhibited 5-HT-induced angiogenesis. In addition, BJ-1108 induced a significant reduction in the size and weight of excised tumors in breast cancer cell-inoculated CAM assay, showing proportionate suppression of tumor growth along with inhibition of angiogenesis. In human umbilical vein endothelial cells (HUVECs), BJ-1108 significantly suppressed 5-HT-induced ROS generation and phosphorylation of PI3K/Akt but not of Src. Unlike NOX inhibitors, BJ-1108, which showed better antioxidant activity than vitamin C, barely suppressed superoxide anion induced by mevalonate or geranylgeranyl pyrophosphate which directly activates NOX without help from other signaling molecules in HUVECs, implying that the anti-angiogenic action of BJ-1108 was not mediated through direct action on NOX activation, or free radical scavenging activity. In conclusion, BJ-1108 inhibited 5-HT-induced angiogenesis through PI3K/NOX signaling but not through Src, ERK, or p38.  相似文献   
62.
63.
Objectives: To provide a simple method to make a stable ΔF508-CFTR-expressing T84 cell line that can be used as an efficient screening model system for ΔF508-CFTR rescue. Results: CFTR knockout cell lines were generated by Cas9 with a single-guide RNA (sgRNA) targeting exon 1 of the CFTR genome, which produced indels that abolished CFTR protein expressions. Next, stable ΔF508-CFTR expression was achieved by genome integration of ΔF508-CFTR via the lentivirus infection system. Finally, we showed functional rescue of ΔF508-CFTR not only by growing the cells at a low temperature, but also incubating with VX-809, a ΔF508-CFTR corrector, in the established T84 cells expressing ΔF508-CFTR. Conclusions: This cell system provides an appropriate screening platform for rescue of ΔF508-CFTR, especially related to protein folding, escaped from endoplasmic-reticulum-associated protein degradation, and membrane transport.  相似文献   
64.
65.
66.
67.
68.
69.
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   
70.
A mechanosensitive, visco‐poroelastic polymer ion pump that can rapidly establish a dense electrical double layer via mechanical pressure, thereby significantly enhancing output performance of an ionic triboelectric nanogenerator (iTENG), is described. A working mechanism of an iTENG using a highly mechanosensitive, visco‐poroelastic ion pump is suggested and the optimal characteristics of the polymer ion pump are reported by investigating optical, mechanical, electrical, and electrochemical properties. Surprisingly, the pressure sensitivity of the iTENG reaches 23.3 V kPa?1, which is tens of times the record value. To achieve controlled high‐frequency pulses from an iTENG, kinematic systems using a gear train and a cam are integrated with a single grounded iTENG, which produces a maximum of 600 V and 22 mA (≈2.2 W cm?2) at an input frequency of 1.67 Hz; after power transforming, those values are converted to 1.42 V and 225 mA. A capacitor of 1 mF can be fully charged to 2 V in only 60 s, making it possible to continuously operate a wireless‐communicating self‐powered humidity sensor. Also, due to the high transparency and deformability of the polymer ion pump, a self‐powered transparent tactile sensor is successfully assembled using a 5 × 5 iTENG array.  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