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   512篇
  免费   14篇
  国内免费   21篇
化学   440篇
晶体学   1篇
力学   2篇
综合类   1篇
数学   20篇
物理学   83篇
  2023年   47篇
  2022年   18篇
  2021年   39篇
  2020年   31篇
  2019年   32篇
  2018年   14篇
  2017年   15篇
  2016年   23篇
  2015年   21篇
  2014年   23篇
  2013年   17篇
  2012年   24篇
  2011年   38篇
  2010年   13篇
  2009年   34篇
  2008年   29篇
  2007年   23篇
  2006年   17篇
  2005年   15篇
  2004年   12篇
  2003年   7篇
  2002年   9篇
  2001年   4篇
  2000年   2篇
  1999年   5篇
  1998年   6篇
  1997年   3篇
  1996年   3篇
  1995年   6篇
  1994年   3篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1990年   4篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
  1980年   1篇
  1977年   1篇
排序方式: 共有547条查询结果,搜索用时 343 毫秒
1.
2.
B. Piccoli  F. Castiglione   《Physica A》2006,370(2):672-680
Cancer immunotherapy aims at stimulating the immune system to react against cancer stealth capabilities. It consists of repeatedly injecting small doses of a tumor-associated molecule one wants the immune system to recognize, until a consistent immune response directed against the tumor cells is observed.

We have applied the theory of optimal control to the problem of finding the optimal schedule of injections of an immunotherapeutic agent against cancer. The method employed works for a general ODE system and can be applied to find the optimal protocol in a variety of clinical problems where the kinetics of the drug or treatment and its influence on the normal physiologic functions have been described by a mathematical model.

We show that the choice of the cost function has dramatic effects on the kind of solution the optimization algorithm is able to find. This provides evidence that a careful ODE model and optimization schema must be designed by mathematicians and clinicians using their proper different perspectives.  相似文献   

3.
Bionized nanoferrite (BNF) particles with high specific power absorption rates were synthesized in the size range of 20–100 nm by high-pressure homogenization for targeted cancer therapy with alternating magnetic fields. Several strategies were used to conjugate antibodies to the BNF particles. These strategies were compared using an immunoassay to find optimal conditions to reach a high immunoreactivity of the final antibody–particle conjugate.  相似文献   
4.
Tumor cells transduced with herpes simplex virus thymidine kinase gene have been intensively applied to the field of positron emission tomography via imaging of its substrate. As a pilot synthesis approach, a facile preparation of 5‐[125I] iodoarabinosyl uridine starting from commercially available uridine is reported herein.  相似文献   
5.
Zheng YF  Xu GW  Liu DY  Xiong JH  Zhang PD  Zhang C  Yang Q  Lv S 《Electrophoresis》2002,23(24):4104-4109
Thirteen normal and modified nucleosides, primarily degradation products of transfer ribonucleic acid (tRNA), were evaluated as potential tumor markers for cancer patients. Their urinary concentrations were determined by means of micellar electrokinetic capillary chromatography (MEKC) in the urine from 54 healthy adults and 70 cancer patients, then quantitatively expressed as a function of creatinine excretion. It was found that urinary nucleosides for cancer patients were on the average significantly higher than those for healthy controls, however, no significant differences were found between male and female or between different ages. Based on 13 urinary nucleoside concentrations, principal component analysis (PCA) could be used to classify 72% of cancer patients from the healthy controls. The present study shows that the precise measurement of urinary nucleosides by MEKC in combining with PCA technique may provide a clinically useful approach for diagnosis of cancer.  相似文献   
6.
α核素211At具有良好的辐射生物学性质,以对肿瘤细胞具有高亲和性的单克隆抗体或多肽类配体为载体则是实现211At肿瘤靶向治疗的最理想方式之一。本文介绍了211At标记蛋白质或多肽的方法的现状与进展,对存在的一些问题及今后的发展方向进行了讨论。  相似文献   
7.
We reported a simple and universal strategy for DNA-mediated assembly of CdTe quantum dots (QDs) and lanthanide-doped upconversion nanoparticles (UCNPs). Such DNA-QD/UCNPs heterostructures not only maintains both fluorescent properties of QDs and upconversion luminescence behaviors of UCNPs, but also offers a polyvalent DNA surface, allowing for targeted dual-modality imaging of cancer cells using an aptamer  相似文献   
8.
血清中Mo、Se、Mn、Cu、Zn与食管癌的关系探讨   总被引:1,自引:0,他引:1  
通过对18例食管癌患者以及80例对照组血清中Mo、Se、Mn、Cu、Zn的测定分析,发现食管瘤患者血硒含量明显低于对照组,二者之间有极显著性差异(P<0.01)。而血铜、铜/锌比值食管癌组明显高于对照组,差异有显著性(P<0.05)。Mo、Mn、Zn元素的含量在二组之间无显著性差异(P>0.05).提示血清硒铜与食管癌有关。  相似文献   
9.
A therapeutic method that selectively destroys malignant cells in the presence of normal cells is a highly valued goal of oncologists and the possible salvation of cancer patients afflicted with some incurable forms of the disease. Selective cell destruction is, in principle, possible with a binary therapeutic strategy based upon the neutron capture reaction observed with the 10B nucleus and a neutron of low kinetic energy (thermal neutron). This nuclear fission reaction produces both 4He and 7Li+ nuclei along with about 2.4 MeV of kinetic energy and weak γ-radiation. Since the energetic and cytotoxic product ions travel only about one cell diameter in tissue one may specify the cell type to be destroyed by placing innocent 10B nuclei on or within only the doomed cells. This article describes the current status of chemical research aimed at the eventual adoption of this therapeutic method (boron neutron capture therapy or BNCT). The multidisciplinary nature of this research effort involves chemistry, biology, nuclear physics, medicine, and related specialties. Methods devised for bringing 10B nuclei to tumor cells in therapeutic amounts are correlated with the structure of a generalized cell and the various cellular compartments available for boron localization. The synthesis methods employed for the creation of boron-containing biomolecules and drugs are presented along with representative data concerning their efficacy in tumor localization. The outlook for BNCT is especially bright at this time because of rapid developments in the fields of bioorganometallic chemistry, microbiology, immunology, and nuclear science, to name but a few. Very effective boron delivery vehicles have been demonstrated, and through the interaction of chemistry and biology these species are undergoing further improvement and evaluation of their suitability for BNCT.  相似文献   
10.
据不同地貌、地质条件在30个县市按剖面、同步、随机取土壤样品372份.测定硒等微量元素含量.作等级相关分析显示。土壤硒含量与消化系统癌呈负相关关系.作相对危险度、剂量-效应及多因素分析,认为此负相关关系并非偶然现象.  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