全文获取类型
收费全文 | 633篇 |
免费 | 44篇 |
国内免费 | 29篇 |
专业分类
系统科学 | 1篇 |
丛书文集 | 18篇 |
教育与普及 | 13篇 |
理论与方法论 | 1篇 |
现状及发展 | 87篇 |
综合类 | 586篇 |
出版年
2023年 | 10篇 |
2022年 | 11篇 |
2021年 | 15篇 |
2020年 | 8篇 |
2019年 | 12篇 |
2018年 | 9篇 |
2017年 | 11篇 |
2016年 | 13篇 |
2015年 | 29篇 |
2014年 | 33篇 |
2013年 | 20篇 |
2012年 | 23篇 |
2011年 | 33篇 |
2010年 | 24篇 |
2009年 | 27篇 |
2008年 | 37篇 |
2007年 | 29篇 |
2006年 | 26篇 |
2005年 | 37篇 |
2004年 | 45篇 |
2003年 | 29篇 |
2002年 | 49篇 |
2001年 | 25篇 |
2000年 | 21篇 |
1999年 | 14篇 |
1998年 | 20篇 |
1997年 | 5篇 |
1996年 | 11篇 |
1995年 | 9篇 |
1994年 | 12篇 |
1993年 | 13篇 |
1992年 | 13篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 1篇 |
排序方式: 共有706条查询结果,搜索用时 31 毫秒
61.
目的研究姜黄素对人低分化鼻咽癌细胞系亚克隆株CNE-2Z-H5裸鼠移植瘤生长和增殖的影响。方法复制人低分化鼻咽癌细胞系亚克隆株CNE-2Z-H5裸鼠移植瘤模型,观察姜黄素对移植瘤生长的影响。结果裸鼠体内实验显示姜黄素可以抑制移植瘤的生长。不同浓度姜黄素组移植瘤瘤重与溶剂对照组比较有降低趋势,高剂量组降低更明显,差异有极显著性(P<0.001),抑瘤率达59.75%。结论姜黄素可以抑制CNE-2Z-H5细胞裸鼠移植瘤的生长,其可能在鼻咽癌的治疗中具有一定的价值,值得进一步深入研究。 相似文献
62.
张易青 《青海师范大学学报(自然科学版)》2003,(3):80-81
2000—2002年进行颈部肿块细针吸取细胞学检查共600例,有病理组织学证实138例,其中恶性病变66例。淋巴结、甲状腺各占60.10%、23.50%。细胞学阳性158例,占26.33%,可疑恶性32例,占5.33%。和术后病理组织学诊断对照。恶性病变符合率80.30%,良性病变符合率为93.06%,总符合率为86.96%。敏感率(阳性 可疑)淋巴结、甲状腺分别为96.29%和90.00%。本文对假阳性、假阴性病例进行了分析。 相似文献
63.
64.
on the human tumor cell growth MA Yewei ZHOU Xiaoshan QIAN Xinlai ZHAO Qingzheng YANG Jun GAO Xin LI Yanchun LIU Yuying & WANG Zheng . Cancer Institute Peking Union Medical College Chinese Acad-emy of Medical Sciences Beijing China . Beijing Institute of Blood Transfusion Medicine Beijing China 《科学通报(英文版)》2003,(7)
The human adenovirus type 5 E1A, a tumor- suppressor gene[1], codes for two major related proteins of 243 amino acids (12S) and 289 amino acids (13S) by al-ternative splicing in two exons[2]. Studies have been shown that E1A can regulate expression of many genes and cell cycle[3]. Both in vitro and in vivo experiments indicated that E1A could induce tumor cells differentia-tion, convert tumor cells into an epithelial phenotype, in-hibit tumor cell growth and metastasis and strongly en-ha… 相似文献
65.
MAYewei ZHOUXiaoshan QIANXinlai ZHAOQingzheng YANGJun GAOXin LIYanchun LIUYuying WANGZheng 《科学通报(英文版)》2003,48(7):687-691
Adenovirus 5 type E1A as a tumor suppressor gene can inhibit tumor growth and enhance the censitivity of chemotherapy and radiotherapy.E1A have the ability to integrate into the host genome,resulting in long-time expres-sion that induces Rb gene inactivation and animal cells im-mortalization.This prompted us to select the E1A protein for treatment of cancer in order to overcome the limitations of E1A gene therapy.Thus,we firstly comstructed E1A eu-caryotic expression vector (pPIC9/E1A),transformated the pichia pastoris yeast cells(GS115) and screened the high-expressing recombinant strains.The positive yeast strains were cultured in the shake flask,and induced for 3d.The crude E1A protein was purified using two steps of col-umu chromatography on HiTrap Q and HiTrap SP.The pu-rified E1A protein was identified by SDS-PAGE and Western blot.E1A protein was mostly located at cellular unclear when Cheriot delivered E1A protein into cells.The analysis in vitro indicated that the E1A protein arrested LN686 cell cycle at G2/M phase,and significantly inhibited the growth of LN686 tumor cells.The current studies firstly provided an experimental basis to further develop E1A protein for tumor treatment. 相似文献
66.
MMP-2、MMP-9及其抑制剂在肺癌中的表达与临床意义 总被引:1,自引:0,他引:1
目的探讨肺癌组织中MMP2、MMP9及其抑制剂的表达与肺癌的生长、转移等临床特征及预后的关系.方法采用免疫组织化学法SP法检测45例肺癌组织中MMP2、MMP9及其抑制剂的表达,观察它们与肺癌的生长、TMN分期的关系.结果MMP2、MMP9、TIMP1和TIMP2在45例肺癌组织中的阳性表达率分别为57.78%(26/45)、37.78%(17/45)、35.56%(16/45)及51.11%(23/45);它们的表达与肺癌的原发灶范围、淋巴结转移、远处转移、TNM分期及平均生存时间有统计学意义(P<0.05).结论MMP2、MMP9及其抑制剂的表达与肺癌的TNM分期及平均生存时间关系密切,它们在组织中的高表达是判断肺癌预后的独立因素. 相似文献
67.
ZHONG Weirong SHAO Yuanzhi HE Zhenhui 《科学通报(英文版)》2005,50(20):2273-2275
Since half a century ago, nonlinear physics has changed our views of world drastically[1]. People expected to use it to solve the complexity of biology[2,3]. In the past decade, more and more evidence shows that noise plays an impor- tant role in nonlinear systems[4―10], such as noise-induced phase transitions, stochastic resonance (SR) and so on. Especially, SR uncovered a heap of complexities of biol- ogy[11,12]. For many years, the law of tumors growth has been a challenging subject. Sci… 相似文献
68.
Increasing evidence implies altered signaling through the neurotrophic receptor tyrosine kinase TrkB in promoting tumor formation
and metastasis. TrkB, sometimes in conjunction with its primary ligand BDNF, is often overexpressed in a variety of human
cancers, ranging from neuroblastomas to pancreatic ductal adenocarcinomas, in which it may allow tumor expansion and contribute
to resistance to anti-tumor agents. In vitro, TrkB acts as a potent suppressor of anoikis (detachment-induced apoptosis), which is associated with the acquisition of
an aggressive tumorigenic and metastatic phenotype in vivo. In view of its predicted contribution to tumorigenicity and metastasis in humans, TrkB corresponds to a potential drug target,
and preclinical models have already been established. The encouraging results of pharmacological Trk inhibitors in tumor xenograft
models suggest that TrkB inhibition may represent a promising novel anti-tumor therapeutic strategy. This hypothesis is currently
being evaluated in clinical trials. Here, we will discuss the latest developments on TrkB in these contexts as well as highlight
some critical questions that remain to be addressed for evaluating TrkB as a therapeutic target in cancer.
Received 12 October 2005; received after revision 19 December 2005; accepted 11 January 2006 相似文献
69.
槲皮素抗癌作用的分子机制 总被引:7,自引:0,他引:7
槲皮素是已知最强的抗癌剂之一。从分子水平的角度阐述了其抗癌作用机制的研究进展。其中包括结合雌激素受体,下调变异的P53蛋白,阻滞细胞周期,抑制酪氨酸激酶,促进凋亡,阻遏热休克蛋白和抑制Ras的表达等等。随着其分子机制的深入研究,可以为临床治疗提供更好的理论依据。 相似文献
70.
老年恶性肿瘤病人化疗中的静脉保护289例 总被引:2,自引:0,他引:2
李桂萍 《内蒙古民族大学学报(自然科学版)》2004,19(3):343-344
总结289例老年恶性肿瘤病人化疗中的静脉保护,化疗前的准备工作对静脉保护极为重要.同时,掌握好给药顺序,选择好静脉,加强巡视,及时排除输液中的故障,严格无菌操作,对化疗中的静脉炎及药物外漏起到了预防作用.并对3例静脉炎及5例药物外漏给予相应的对症处理,无局部组织溃疡、坏死等并发症,从而顺利完成了老年恶性肿瘤病人的全程静脉化疗,延长了病人的生存期,提高了治愈率. 相似文献