全文获取类型
收费全文 | 325篇 |
免费 | 20篇 |
国内免费 | 56篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 8篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 18篇 |
2014年 | 14篇 |
2013年 | 22篇 |
2012年 | 33篇 |
2011年 | 26篇 |
2010年 | 24篇 |
2009年 | 18篇 |
2008年 | 39篇 |
2007年 | 25篇 |
2006年 | 29篇 |
2005年 | 32篇 |
2004年 | 23篇 |
2003年 | 17篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1991年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有401条查询结果,搜索用时 46 毫秒
1.
2.
Forskolin(FSK)是一种植物二萜类化合物,为腺苷酸环化酶的特异激活剂,实验发现:FSK和作为参照的诱导分化剂维甲酸(RA)单独或联合应用均可升高胞浆蛋白激酶C(PKC)活性,并降低膜PKC活性,FSK可使表皮生长因子(EGF)诱导的细胞内三磷酸肌醇(IP3-1,4,5)水平降低至对照组的44.4%至67%;FSK与RA合用可显著降低成骨样细胞特征蛋白碱性磷酸酶(AKP)的活性。以上结果表明,FSK对成骨样细胞内磷脂酰肌醇信息传递体系有深刻影响,可能与其调节细胞的增殖分化有关。 相似文献
3.
Jun-Wen Qiao∗ Xiao-Ou Su∗ Yu-Xing Li Jian-Min Yang Yi-Qin Wang Mohammed Kouadir 《Animal biotechnology》2013,24(3):151-155
The 37-kDa laminin receptor precursor/67-kDa laminin receptor (LRP/LR, also known as ribosomal protein SA, RPSA) has been reported to be involved in cancer development and prion internalization. Previous studies have shown that the LRP/LR is expressed in a wide variety of tissues. In particular, expression of LRP/LR mRNA may be closely related to the degree of PrPSc propagation. This study presents a detailed investigation of the LRP/LR mRNA expression levels in eleven normal ovine tissues. Using real-time quantitative PCR, the highest LRP/LR expression was found in neocortex (p < 0.05). Slightly lower levels were found in the heart and obex. Intermediate levels were seen in hippocampus, cerebellum, spleen, thalamus, mesenteric lymph node, and the lowest levels were present in liver, kidney, and lung. In general, the LRP/LR mRNA levels were much higher in neuronal tissues than in peripheral tissues. The observation that differences in LRP/LR mRNA expression levels are consistent with the corresponding variation in PrPSc accumulation suggests that the 37-kDa/67-kDa laminin receptor may be involved in the regulation of PrPSc propagation. 相似文献
4.
Kai-Jun Zhao Yi-Bin Fang Qing-Hai Huang Yi Xu Bo Hong Qiang Li Jian-Min Liu Wen-Yuan Zhao Ben-Qiang Deng 《PloS one》2013,8(6)
Introduction
Few studies focused on predictors of unfavorable outcomes (modified Rankin Scale, 2–6) after reconstructive treatment of the ruptured intracranial spontaneous vertebral artery dissection aneurysms (ris-VADAs), which was evaluated based on 57 reconstructed lesions in this study.Methods
Results of 57 consecutive patients (M:F = 29∶28; median age, 48 years; range, 27 to 69 years) harboring 57 ris-VADAs, which were treated with coils combined with single stent(n = 32), double overlapping stents (n = 16), and triple overlapping stents (n = 9) between October 2000 to March 2011, were retrospectively reviewed and analyzed.Results
The available (n = 54) mean durations of angiographic and clinical follow-ups were 27 months (range, 12 to 78) and 62 months (range, 12 to 132), respectively. The involvement of PICA (p = 0.004), size of lesions (p = 0.000), quantity of stent (p = 0.001), and coil type (p = 0.002) affected the immediate obliteration grade, which was only risk factor for angiographic recurrences (p = 0.031). Although the post-treatment outcomes did not differ between single stent and multiple stents (p = 0.434), 5 angiographic recurrences, 1 rebleeding and 1 suspected rebleeding, all occurred in partial obliteration after single-stent-assisted coiling. Progressive thrombosis and in-stent obliteration were not detected on follow-up angiograms. Older age (odds ratio [OR] = 1.090; 95% confidence interval [CI], 1.004–1.184; p = 0.040) and unfavorable Hunt-Hess scale (OR = 4.289; 95%CI, 1.232–14.933; p = 0.022) were independent predictors of unfavorable outcomes in the reconstructed ris-VADAs.Conclusions
Immediate obliteration grade was only risk factor for angiographic recurrence after reconstructive treatment. Unfavorable Hunt-Hess grade and older age were independent predictors of unfavorable outcomes in ris-VADAs. 相似文献5.
Geng-Qing Huang Wen Li Wei Zhou Jian-Min Zhang Deng-Di Li Si-Ying Gong Xue-Bao Li 《Plant Growth Regulation》2013,71(2):101-112
6.
Bharat Thyagarajan Renwei Wang Heather Nelson Helene Barcelo Woon-Puay Koh Jian-Min Yuan 《PloS one》2013,8(6)
Mitochondrial DNA (mtDNA) copy number in peripheral blood is associated with increased risk of several cancers. However, data from prospective studies on mtDNA copy number and breast cancer risk are lacking. We evaluated the association between mtDNA copy number in peripheral blood and breast cancer risk in a nested case-control study of 183 breast cancer cases with pre-diagnostic blood samples and 529 individually matched controls among participants of the Singapore Chinese Health Study. The mtDNA copy number was measured using real time PCR. Conditional logistic regression analyses showed that there was an overall positive association between mtDNA copy number and breast cancer risk (Ptrend = 0.01). The elevated risk for higher mtDNA copy numbers was primarily seen for women with <3 years between blood draw and cancer diagnosis; ORs (95% CIs) for 2nd, 3rd, 4th, and 5th quintile of mtDNA copy number were 1.52 (0.61, 3.82), 2.52 (1.03, 6.12), 3.12 (1.31, 7.43), and 3.06 (1.25, 7.47), respectively, compared with the 1st quintile (Ptrend = 0.004). There was no association between mtDNA copy number and breast cancer risk among women who donated a blood sample ≥3 years before breast cancer diagnosis (Ptrend = 0.41). This study supports a prospective association between increased mtDNA copy number and breast cancer risk that is dependent on the time interval between blood collection and breast cancer diagnosis. Future studies are warranted to confirm these findings and to elucidate the biological role of mtDNA copy number in breast cancer risk. 相似文献
7.
Kai-Jun Zhao Yong-Wei Zhang Yi Xu Bo Hong Qing-Hai Huang Wen-Yuan Zhao Peng-Fei Yang Jian-Min Liu 《PloS one》2013,8(2)
Introduction
We aimed to evaluate the feasibility, safety, efficacy, and predictors for outcome of reconstructive treatment with Solitaire™ AB stent(s) based on 54 cases of saccular aneurysms and 14 of acute symptomatic dissecting aneurysms.Methods
Fifty-eight consecutive patients (M/F = 28/30; median age, 53 years) harbouring 68 aneurysms (ruptured/unruptured = 12/56) underwent treatment with Solitaire™ AB stent(s) implantation between April 2010 and August 2011 in our institution. The data were retrospectively reviewed and analysed.Results
The technical success rate of Solitaire™ AB stenting was 100%. The rates of the overall and the treatment-related adverse events were 9% (6/68) and 6% (4/68), respectively, and the recurrent rate was 1% (1/68). All of the adverse events (n = 6) occurred in tiny (n = 1, ≤3 mm) or small (n = 5, >3 to ≤10 mm) aneurysms. The majority (75%, 3/4) of thromboembolic events (thrombus, n = 2; infarction, n = 2) occurred in ruptured lesions, and 2 intraprocedural aneurysm ruptures occurred in the course of coiling when the stent(s) was/were applied within 6 months. Subarachnoid haemorrhages (SAH, p<0.05) and immediate occlusion grades (p<0.05) were predictors for overall adverse events by univariate analysis. Compared with the immediate post-treatment angiographic results, the follow-up angiographic imaging (mean, 13 months; range, 6–25 months) revealed that stent(s) implantation enhanced the rate of class I occlusion from 34% (23/68) to 93% (63/68). SAH was the only predictor for unfavourable outcomes (the modified Rankin Scale score [mRS], 2–6) during the mean 19-month (range, 12–27 months) of clinical follow-ups (p<0.05).Conclusions
Although the complete obliteration of tiny and small aneurysms without complications remains a challenge, stent(s) implantation could lead to further occlusion of incompletely coiled aneurysms. SAH and the occlusion grade were the primary predictors for adverse events. SAH was the only predictor for unfavourable outcomes by univariate analysis. 相似文献8.
正2013年7月9日,在河南省洛阳市栾川县老君山主峰西侧追梦谷(33°45′26″N,111°38′33″E,海拔830 m),进行蜻蜓多样性专项调查时,偶遇当地村民手中抓着两只漂亮的小鸟。经过仔细观察和辨认,鉴定为红胸啄花鸟(Dicaeum ignipectus),一雌一雄。我们将其带回"河南省林业厅林业有害生物防控重点实验室"精心喂养。两只红胸啄花鸟标本现保存于河南林业职业学院野生动物标本馆。经过查阅《中国鸟类分类与分布名录(第二版)》(郑光美2011)、《中国鸟类分布名录》(郑作新1976)、《中 相似文献
9.
该研究在江西省瑞昌市设置9个淡竹林样地,调查和测定了淡竹林密度、淡竹各构件的生物量和总生物量,以及土壤含水率、土层厚度、林下裸岩率、pH、电导率、全氮和全磷等7个土壤环境因子,并对竹林密度、土壤环境因子和淡竹生物量分配指标进行了相关分析和回归分析。结果表明:(1)密度与淡竹蔸比重相关系数r达0.66( P=0.02<0.05),而与叶比重、枝比重、秆比重、鞭比重、根比重及根冠比均无显著相关关系;土壤环境因子与生物量分配指标有密切相关,环境主成分Z1与叶比重、秆比重及蔸比重均显著相关(P<0.05),Z2与鞭比重显著相关(P=0.034<0.05)。(2)密度与土壤环境因子密切相关(P<0.05),控制土壤环境因子的偏相关分析显示密度与淡竹生物量分配不显著相关( P>0.05),而控制密度时,土壤环境因子与淡竹生物量分配仍有显著相关关系(P<0.05);逐步回归分析也验证了偏相关分析的结果,密度被排除出回归方程。分析认为,土壤含水率、土层厚度及土壤养分等环境因子是影响石灰岩山地优势种淡竹生物量分配的主因,密度对生物量分配的影响实为土壤环境因子的间接作用。该研究结果为石灰岩地区植被恢复提供了理论支撑。 相似文献
10.
Luo Lilan He Yajun Zhao Yannan Xu Qian Wu Jian Ma Haiyan Guo Hongyan Bai Lin Zuo Jianru Zhou Jian-Min Yu Hong Li Jiayang 《中国科学:生命科学英文版》2019,62(8):991-1002
Reactive oxygen species(ROS) play a crucial role in numerous biological processes in plants, including development, responses to environmental stimuli, and programmed cell death(PCD). Deficiency in MOSAIC DEATH 1(MOD1), a plastid-localized enoyl-ACP reductase essential for de novo fatty acid biosynthesis in Arabidopsis thaliana, leads to the increased malate export from chloroplasts to mitochondria, and the subsequent accumulation of mitochondria-generated ROS and PCD. In this study, we report the identification and characterization of a mod1 suppressor, som592. SOM592 encodes mitochondrion-localized NAD~+ transporter 2(NDT2). We show that the mitochondrial NAD pool is elevated in the mod1 mutant. The som592 mutation fully suppressed mitochondrial NADH hyper-accumulation, ROS production, and PCD in the mod1 mutant, indicating a causal relationship between mitochondrial NAD accumulation and ROS/PCD phenotypes. We also show that in wild-type plants, the mitochondrial NAD+uptake is involved in the regulation of ROS production in response to continuous photoperiod. Elevation of the alternative respiration pathway can suppress ROS accumulation and PCD in mod1, but leads to growth restriction. These findings uncover a regulatory mechanism for mitochondrial ROS production via NADH homeostasis in Arabidopsis thaliana that is likely important for growth regulation in response to altered photoperiod. 相似文献