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   437篇
  免费   20篇
  国内免费   44篇
化学   318篇
力学   24篇
综合类   11篇
数学   56篇
物理学   92篇
  2024年   3篇
  2023年   26篇
  2022年   26篇
  2021年   35篇
  2020年   19篇
  2019年   19篇
  2018年   15篇
  2017年   11篇
  2016年   15篇
  2015年   19篇
  2014年   23篇
  2013年   19篇
  2012年   39篇
  2011年   28篇
  2010年   17篇
  2009年   25篇
  2008年   24篇
  2007年   23篇
  2006年   17篇
  2005年   11篇
  2004年   12篇
  2003年   6篇
  2002年   9篇
  2001年   11篇
  2000年   5篇
  1999年   7篇
  1998年   6篇
  1997年   12篇
  1996年   6篇
  1995年   4篇
  1994年   1篇
  1993年   1篇
  1992年   3篇
  1991年   1篇
  1988年   1篇
  1985年   1篇
  1968年   1篇
排序方式: 共有501条查询结果,搜索用时 46 毫秒
31.
Aptamer is an oligonucleotide chain with specific binding ability to protein and other targets,which is widely used in ma ny fields.Because of its ability to screen the premise of unknown targets,it can be used to discover some novel tumor markers,i.e.,membrane proteins that are specifically highly expressed on the surface of tumor cells.Tumor markers can be used in many fields such as early diagnosis and treatment,and a new type of tumor marker proved to be effective can significantly improve the therapeutic effect of such tumors.However,further characterization of newly acquired membrane proteins is essential for their clinical use as tumor markers.This review first briefly introduced the process of obtaining novel tumor markers from nucleic acid aptamers.Next,the commonly used protein characterization methods could be used as a technical means to identify membrane protein targets corresponding to tumor cell aptamers,to clarify the principles,advantages and disadvantages of various means,and to analyze the most suitable situations for various experimental methods.Finally,the outlook was made and the characterization methods that should be used in such experiments were summarized.  相似文献   
32.
We observed the polymorphism distribution and coaction of uncoupling protein 3(UCP3)-55C/T,adiponectin(APN)+45T/G and tumor necrosis factor(TNF)-a-308G/A on the onset and development of T2DM in a North...  相似文献   
33.
Multi-functionalized single walled carbon nanotubes (SWNTs) were prepared and applied as tumor cell targeting biological transporters. A positive charge was introduced on SWNTs to get high loading efficiency of fluorescein (FAM) labeled short double strands DNA (20 base pairs). The SWNTs were encapsulated with the folic acid modified phospholipids for active targeting into tumor cell. The tumor cell-targeting properties of these multi-functionalized SWNTs were investigated by active targeting into mouse ovarian surface epithelial cells. The experimental results show that these multi-functionalized SWNTs have good tumor cell targeting property.  相似文献   
34.
Ethyl glucuronide (EtG) is a marker of recent alcohol consumption. For the optimization of the analysis of EtG by CZE with indirect absorbance detection, the use of capillaries with permanent and dynamic wall coatings, the composition of the BGE, and various sample preparation procedures, including dilution with water, ultrafiltration, protein precipitation, and SPE, were investigated. Two validated screening assays for the determination of EtG in human serum, a CZE‐based approach and an enzyme immunoassay (EIA), are described. The CZE assay uses a coated capillary, 2,4‐dimethylglutaric acid as an internal standard, and a pH 4.65 BGE comprising 9 mM nicotinic acid, ε‐aminocaproic acid and 10% v/v ACN. Proteins are removed via precipitation with ACN prior to analysis and the LOQ is 0.50 mg/L. The EIA is based upon commercial reagents which are promoted for the determination of urinary EtG. Krebs–Ringer solution containing 5% BSA is used as a calibration matrix. All samples are ultrafiltered prior to analysis of the ultrafiltrate on a Mira Plus analyzer. Assay calibration ranged between 0 and 2 mg/L and the upper reference limit was determined to be 0.05 mg/L. Both assays proved to be suitable for the analysis of samples from different individuals. For EtG levels above 0.50 mg/L, good agreement was observed for the comparison of the results of the two methods.  相似文献   
35.
<正>The chemokine CXCR4 receptor is over-expressed in a wide variety of tumors.In this study,AMD3100,which was a prototype non-peptide antagonist of CXCR4 receptor,was labeled with ~(99m)Tc.~(99m)Tc-AMD3100 was verified by thin layer radio chromatography(TLRC).The tumor-localizing properties of ~(99m)Tc-AMD3100 were evaluated and proved in mice bearing Hep-G2 tumor xenograft.~(99m)Tc-AMD3100 was a promising,novel receptor-specific radiopharmaceutical with potential application in the imaging of human tumors.  相似文献   
36.
37.
应用FTIR分析经染色处理的妇科肿瘤组织切片及常规红外切片,将二者的红外光谱图与正常组织的红外光谱图对照.结果显示,经染色处理的肿瘤组织的各特征峰与未经染色的肿瘤组织的特征峰大体一致,二者与正常组织的红外光谱相比,都具有明显且有规律的差异,说明FTIR直接对经染色处理的肿瘤组织切片进行红外分析以作为肿瘤诊断的依据是可行...  相似文献   
38.
《偏微分方程通讯》2013,38(3-4):517-560
Abstract

In this article, we study a free boundary problem for a system of two partial differential equations, one parabolic and other elliptic. The system models the growth of a tumor with arbitrary initial shape. We establish the existence and uniqueness of a solution for some time interval. In the special case where we only have the elliptic equation, the problem coincides with the Hele–Shaw problem.  相似文献   
39.
肿瘤组织自体荧光光谱测量与分析   总被引:4,自引:2,他引:2  
首先介绍了对人工培养鼠肿瘤组织的激光诱导荧光光谱的实验测量结果,并与同一机体正常组织的自体荧光光谱进行了比较,然后对肿瘤组织自体荧光的来源,与正常组织光谱特征差异的本质进行了详细分析,从而得出结论,生物组织自体荧光光谱能够反映肿瘤组织的特异性,可以作为组织诊断的依据。  相似文献   
40.
该文研究根据Byrne和Chaplain的思想建立的一个描述抑制物作用下无坏死核肿瘤生长的数学模型, 这个模型是一个非线性反应扩散方程组的自由边界问题. 作者运用反应扩散方程理论中的上下解方法结合自由边界问题的迭代技巧, 研究了解的渐近性态, 在营养物消耗函数f、抑制物消耗函数g和肿瘤细胞繁衍函数S的一些一般条件下,证明当常数c1,c2(肿瘤细胞分裂速率和营养物、抑制物扩散速率的比值)都非常小时,在一定的初边值条件下肿瘤趋于消失,在另外一些初边值条件下肿瘤半径趋于一个常数,进而时变解将趋于一个稳态解.  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