全文获取类型
收费全文 | 232篇 |
免费 | 13篇 |
国内免费 | 9篇 |
专业分类
254篇 |
出版年
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 5篇 |
2015年 | 20篇 |
2014年 | 13篇 |
2013年 | 12篇 |
2012年 | 11篇 |
2011年 | 36篇 |
2010年 | 13篇 |
2009年 | 11篇 |
2008年 | 7篇 |
2007年 | 7篇 |
2006年 | 10篇 |
2005年 | 3篇 |
2004年 | 8篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 7篇 |
2000年 | 2篇 |
1999年 | 7篇 |
1998年 | 9篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 7篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1982年 | 2篇 |
1977年 | 2篇 |
1955年 | 1篇 |
1954年 | 2篇 |
排序方式: 共有254条查询结果,搜索用时 0 毫秒
41.
人肺腺癌细胞分化相关基因cDNAs的克隆 总被引:2,自引:0,他引:2
在用10-5 mol/L全反式维甲酸(RA)诱导人肺腺癌细胞系GLC-82分化的基础上,以M13噬菌粒pSPORT1为载体,应用定向克隆技术,分别构建了未经RA诱导和RA诱导1d及4d细胞的3个cDNA文库.以含重组子的诱导文库单链DNA为靶标(Target)同未诱导文库的cDNA驱除子(Driver)进行消减杂交,富集RA特异性单链DNA,将富集的单链DNA回复为双链后转化感受态菌,建立细胞诱导分化过程中活化表达基因的cDNA消减文库,得到124个cDNA消减克隆.经同源性分析和与文库总cDNA作Southern印迹杂交,进而与RA诱导前后细胞的RNA作Northern印迹杂交,筛选出2个(RA5,RA28)诱导后呈早期瞬时表达和1个(RA42)呈早期并持续表达的cDNA克隆,cDNA全长分别为1.8,1.5和0.7kb.序列测定及初步功能分析结果表明,RA5,RA28和RA42这3个首次报道的序列,可能是人肺腺癌细胞分化相关基因的cDNA克隆. 相似文献
42.
Sarah Jamali Annick Salzmann Nader Perroud Magali Ponsole-Lenfant Jennifer Cillario Patrice Roll Nathalie Roeckel-Trevisiol Ariel Crespel Jorg Balzar Kurt Schlachter Ursula Gruber-Sedlmayr Ekaterina Pataraia Christoph Baumgartner Alexander Zimprich Fritz Zimprich Alain Malafosse Pierre Szepetowski 《PloS one》2010,5(9)
43.
Adorian Taida Juliana Jamali Hadi Farsani Hamed Ghafari Darvishi Paria Hasanpour Soleiman Bagheri Tahereh Roozbehfar Reza 《Probiotics and antimicrobial proteins》2019,11(1):248-255
Probiotics and Antimicrobial Proteins - This study was conducted to evaluate different doses of two species of Bacillus (Bacillus licheniformis and Bacillus subtilis), on growth parameters,... 相似文献
44.
在人参(Panax ginseng C.A.Meyer)悬浮细胞质膜上测出了NAD(P)H氧化酶活性。这类NAD(P)H氧化酶活性可以被金瓜炭疽细胞壁激发子(Cle)诱导。Cle处理还能诱导人参悬浮细胞的氧进发、促进人参悬浮细胞的皂苷合成、提高苯丙氨酸解氨酶(PAL)的活力、以及诱导查尔式酮酶(CHS)的累积和细胞壁上抗性相关蛋白基因脯氨酸富裕蛋白基因hrgp(Hydroxyprolin-rich glycoproleins)的表达。当用哺乳动物白细胞质膜NADPH氧化酶的特异性抑制剂二亚苯基碘(Diphenylene iodonium,DPI)与奎吖因(quinacrine)预处理人参悬浮细胞30 min 后,Cle诱导的H2O2释放与Cle激活的质膜NAD(P)H氧化酶活性被抑制,同时Cle诱导的PAL活性及CHS的积累下降,皂苷合成与hrgp的表达被抑制。由此推测:人参细胞质膜NAD(P)H氧化酶与哺乳动物白细胞质膜NADPH氧化酶有很大的相似性。在Cle激发人参悬浮细胞产生氧进发的过程中,NAD(P)H氧化酶活性被诱导从而导致H2O2的产生,H2O2作为第二信使,激活苯丙氨酸途径,诱发人参皂苷的合成及hrgp防御基因的表达。这一过程中还涉及到Ca2+内流,胞内Ca2+浓度的升高,蛋白磷酸化与去磷酸化。人参细胞质膜NAD(P)H氧化酶在人参细胞对Cle的反应过程中起一种介导作用。因此可能存在由Cle刺激,NAD(P)H氧化酶被诱导,H2O2释放,到人 相似文献
45.
Genetic tailoring of N-linked oligosaccharides: the role of glucose residues in glycoprotein processing of Saccharomyces cerevisiae in vivo 总被引:1,自引:0,他引:1
In higher eukaryotes a quality control system monitoring the folding state
of glycoproteins is located in the ER and is composed of the proteins
calnexin, calreticulin, glucosidase II, and UDP-glucose: glycoprotein
glucosyltransferase. It is believed that the innermost glucose residue of
the N- linked oligosaccharide of a glycoprotein serves as a tag in this
control system and therefore performs an important function in the protein
folding pathway. To address this function, we constructed Saccharomyces
cerevisiae strains which contain nonglucosylated (G0), monoglucosylated
(G1), or diglucosylated (G2) glycoproteins in the ER and used these strains
to study the role of glucose residues in the ER processing of
glycoproteins. These alterations of the oligosaccharide structure did not
result in a growth phenotype, but the induction of the unfolded protein
response upon treatment with DTT was much higher in G0 and G2 strains as
compared to wild-type and G1 strains. Our results provide in vivo evidence
that the G1 oligosaccharide is an active oligosaccharide structure in the
ER glycoprotein processing pathway of S.cerevisiae. Furthermore, by
analyzing N- linked oligosaccharides of the constructed strains we can
directly show that no general glycoprotein glucosyltransferase exists in S.
cerevisiae.
相似文献
46.
47.
Stimulation of poly(ADP-ribose) synthesis by free radicals in C3H10T1/2 cells: relationship with NAD metabolism and DNA breakage 总被引:1,自引:0,他引:1
D Lautier D Poirier A Boudreau M A Alaoui Jamali A Castonguay G Poirier 《Biochimie et biologie cellulaire》1990,68(3):602-608
We have studied the effect of H2O2 and O2- produced by xanthine and xanthine oxidase on NAD catabolism, poly(ADP-ribose) synthesis, and production of DNA single-strand breaks in C3H10T1/2 cells. The results show a correlation between the induction of DNA single-strand breaks, the decrease of NAD pool, and the accumulation of polymer. New techniques, based on affinity chromatography and reversed-phase high pressure liquid chromatography, have allowed an accurate determination of polymer contents and showed a 20-fold stimulation of polymer biosynthesis induced by active oxygen species. Inhibition experiments performed with 3-aminobenzamide have shown that the decrease in NAD levels after exposure of cells to active oxygen species was caused by stimulation of poly(ADP-ribosyl)ation and of another cellular process. 相似文献
48.
东亚飞蝗hunchback基因在卵子形成和胚胎发育过程中的原位表达 总被引:1,自引:0,他引:1
hb(hunchback)基因是昆虫胚胎前后轴模式形成的关键基因.对东亚飞蝗(Locusta migratoria manilensis,Meyen)hb基因的功能已有报道,但其表达模式还不清楚.为了研究胁基因在东亚飞蝗卵子形成和胚胎发育过程中的时空表达情况,本研究采用免疫组化方法在蛋白质水平上检测了hb基因的时空表达模式.在卵子形成过程中,hb基因局限在卵细胞核区中表达,随着卵子的发育逐渐移至卵细胞的后端;卵受精后,核区里的Hb蛋白向外扩散,在卵后端形成浓度梯度;胚盘期,hb基因在胚盘中央呈带状表达;胚盘分化为原头和原躯干后,表达条带变宽,并呈现出梯度表达,该表达区域将形成颌、胸部的部分体节;随着腹节开始形成,hb基因在颌胸部的表达逐渐减弱,而在腹部后端的“生长区”表达,并呈现出不连续性.经比较,hb易基因在昆虫颌胸部的表达较为保守,而在卵子形成过程中和腹部的表达具有较大的变异性.与黑腹果蝇等长胚带昆虫相比,东亚飞蝗hb基因在体节形成的基因级联调控中具有更重要、更直接的调控作用. 相似文献
49.
50.
Hassan Imran Afridi Tasneem Gul Kazi Naveed Kazi Ghulam Abbas Kandhro Jameel Ahmed Baig Mohammad Khan Jamali Mohammad Balal Arain Abdul Qadir Shah 《Biological trace element research》2011,139(3):368-268
The pathogenesis of some cardiovascular diseases (CVDs) has been altered with changes in the balance of certain trace and
toxic elements. The aim of the present study was to assess the role of zinc (Zn) and cadmium (Cd) in smoker and nonsmoker
male CVD patients (n = 457) of two age groups (31–45) and (46–60). The both elements were determined in biological samples (scalp hair, blood,
and urine) of CVD patients and healthy referents for comparison purpose. The concentrations of Zn and Cd were measured by
atomic absorption spectrophotometer prior to microwave-assisted acid digestion. It was observed that the mean values of Cd
were significantly higher in the biological samples of smokers CVD as compared to nonsmoker CVD patients, while the level
of Zn was lower in both smoker and nonsmoker patients. The concentrations of Zn in whole blood and scalp hair samples were
lower in CVD patients as compared to referents (p > 0.001). Results showed significant changes of levels of Cd and Zn in blood and scalp hair samples of CVD patients when
compared with healthy referents, while reverse in the case of urine samples. It was observed that low Zn levels were associated
with both smoker and nonsmoker CVD patients, while increased cadmium accumulation was observed in smoker patients as compared
to nonsmoker patients (p > 0.025). 相似文献