全文获取类型
收费全文 | 1827篇 |
免费 | 157篇 |
国内免费 | 191篇 |
专业分类
2175篇 |
出版年
2024年 | 11篇 |
2023年 | 27篇 |
2022年 | 54篇 |
2021年 | 91篇 |
2020年 | 81篇 |
2019年 | 86篇 |
2018年 | 59篇 |
2017年 | 60篇 |
2016年 | 72篇 |
2015年 | 113篇 |
2014年 | 134篇 |
2013年 | 144篇 |
2012年 | 166篇 |
2011年 | 144篇 |
2010年 | 107篇 |
2009年 | 88篇 |
2008年 | 119篇 |
2007年 | 69篇 |
2006年 | 63篇 |
2005年 | 54篇 |
2004年 | 46篇 |
2003年 | 39篇 |
2002年 | 42篇 |
2001年 | 35篇 |
2000年 | 34篇 |
1999年 | 37篇 |
1998年 | 17篇 |
1997年 | 12篇 |
1996年 | 14篇 |
1995年 | 22篇 |
1994年 | 18篇 |
1993年 | 10篇 |
1992年 | 12篇 |
1991年 | 15篇 |
1990年 | 10篇 |
1989年 | 14篇 |
1988年 | 14篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1973年 | 1篇 |
1967年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有2175条查询结果,搜索用时 15 毫秒
951.
Yan‐Xiang Qi Jin‐Ji Pu Xin Zhang He Zhang Ying Lu Qun‐Fang Yu Hui‐Qiang Zhang Yi‐Xian Xie 《Journal of Phytopathology》2013,161(10):735-738
During 2009–2011, a dieback disease of mango (Mangifera indica) has recently emerged on mango trees in Panzhihua City, Sichuan province of China. The disease is characterized by large irregular brown‐coloured speckles on the petioles and twigs, vascular necrosis and dry leaves and complete twig mortality. Fusarium species were isolated repeatedly from the infected petioles and twigs. The species was identified as Fusarium decemcellulare Brick based on morphology and sequence analysis of Translation Elongation Factor‐1alpha (TEF‐1α) gene. Koch's postulates were fulfilled by pathogenicity tests on potted mango seedlings. To our knowledge, this is the first record of dieback on mango caused by F. decemcellulare in China. 相似文献
952.
Qingqing Xiao Xinyu Che Bin Cai Zhenyu Tao Hengyuan Zhang Qin Shao Jun Pu 《Journal of cellular and molecular medicine》2020,24(1):260-275
The vulnerable plaque is a key distinguishing feature of atherosclerotic lesions that can cause acute atherothrombotic vascular disease. This study was designed to explore the effect of autophagy on mitochondria‐mediated macrophage apoptosis and vulnerable plaques. Here, we generated the mouse model of vulnerable carotid plaque in ApoE?/? mice. Application of ApoE?/? mice with rapamycin (an autophagy inducer) inhibited necrotic core formation in vulnerable plaques by decreasing macrophage apoptosis. However, 3‐methyladenine (an autophagy inhibitor) promoted plaque vulnerability through deteriorating these indexes. To further explore the mechanism of autophagy on macrophage apoptosis, we used macrophage apoptosis model in vitro and found that 7‐ketocholesterol (7‐KC, one of the primary oxysterols in oxLDL) caused macrophage apoptosis with concomitant impairment of mitochondria, characterized by the impairment of mitochondrial ultrastructure, cytochrome c release, mitochondrial potential dissipation, mitochondrial fragmentation, excessive ROS generation and both caspase‐9 and caspase‐3 activation. Interestingly, such mitochondrial apoptotic responses were ameliorated by autophagy activator, but exacerbated by autophagy inhibitor. Finally, we found that MAPK‐NF‐κB signalling pathway was involved in autophagy modulation of 7‐KC–induced macrophage apoptosis. So, we provide strong evidence for the potential therapeutic benefit of macrophage autophagy in regulating mitochondria‐mediated apoptosis and inhibiting necrotic core formation in vulnerable plaques. 相似文献
953.
954.
955.
本研究通过以东亚钳蝎毒腺为研究材料,采用TRIzol法分离透明质酸酶的全基因序列,并从中分离出4个东亚钳蝎透明质酸酶序列,分别命名为BmHYⅠ、BmHYⅡ、BmHYⅢ和BmHYⅣ。BmHYⅠcDNA全长是1423 bp,包括42 bp的5’非翻译区,1230 bp的开放阅读框,编码了一个410个氨基酸,还有151 bp的3’非翻译区;BmHYⅠ中包含5个糖基化位点;与其它物种蛋白质比对结果显示,BmHYⅠ中有10个高度保守半胱氨酸残基形成5个二硫键。BmHYⅠ在二级结构中形成了13个螺旋和14个折叠,其中折叠主要分布在N端和C端。系统进化树结构表明,东亚钳蝎BmHYⅠ与其它蝎子物种透明质酸酶亲缘关系最近,其次是蜘蛛,最后是脊椎动物。而BmHYⅡ、BmHYⅢ和BmHYⅣ序列缺少终止密码子,蛋白序列与BmHYⅠ具有高度同源性。本研究结果为进一步透明质酸酶的功能提供数据参考。 相似文献
956.
Shi‐Xin Zhou Yong Zhu Liang‐Fang Wang Ya‐Ping Zheng Jin‐Feng Chen Ting‐Ting Li Xue‐Mei Yang He Wang Xu‐Pu Li Xiao‐Chun Ma Ji‐Qun Zhao Mei Pu Hui Feng Yan Li Jing Fan Ji‐Wei Zhang Yan‐Yan Huang Wen‐Ming Wang 《植物学报(英文版)》2020,62(8):1213-1226
MicroRNAs (miRNAs) are known to fine‐tune growth, development, and stress‐induced responses. Osa‐miR1873 is a rice‐specific miRNA targeting LOC_Os05g01790. Here, we show that Osa‐miR1873 fine‐tunes rice immunity against Magnaporthe oryzae and yield traits via LOC_Os05g01790. Osa‐miR1873 was significantly upregulated in a susceptible accession but downregulated in a resistance accession at 24 h post‐inoculation (hpi) of M. oryzae. Overexpressing Osa‐miR1873 enhanced susceptibility to M. oryzae and compromised induction of defense responses. In contrast, blocking Osa‐miR1873 through target mimicry compromised susceptibility to M. oryzae and enhanced induction of defense responses. Altered expression of Osa‐miR1873 also resulted in some defects in yield traits, including grain numbers and seed setting rate. Moreover, overexpression of the target gene LOC_Os05g01790 increased rice blast disease resistance but severely penalized growth and yield. Taken together, we demonstrate that Osa‐miR1873 fine‐tunes the rice immunity‐growth trade‐off via LOC_Os05g01790, and blocking Osa‐miR1873 could improve blast disease resistance without significant yield penalty. Thus, the Osa‐miR1873‐LOC_Os05g01790 regulatory module is valuable in balancing yield traits and blast resistance. 相似文献
957.
Xiangyan Dai Deyong Pu Liping Wang Xinkai Cheng Xiaoqin Liu Zhan Yin Zhijian Wang 《Journal of fish biology》2021,99(3):1071-1078
The presence of breeding tubercles (BTs) on the pectoral fins has been investigated as a typical male secondary sexual characteristic (SSC) that distinguish males from females in adult zebrafish. Nonetheless, the earliest occurrence of these tubercles and its association with puberty onset and body growth remain unclear. In this study, using morphological, histological and statistical analyses, the authors examined the first appearance of BTs and puberty onset in male zebrafish, with particular emphasis on the potential impact of body growth on them. The results of this study revealed that BTs distributed along the first five branched pectoral fin rays were the earliest manifestation of male SSCs, which is significantly strongly correlated with body weight (R2 = 0.9609, P < 0.001), and could be used as a “gold standard” for the earliest sex distinction (<0.1 g in weight). Using the first appearance of BTs (<0.20 mm2) as a metric, the authors established that male puberty commenced at a body weight of c. 0.056 ± 0.015 g or a standard length of 10.99 ± 1.051 mm (mean ± S.D. ). In this study, the authors thus established a simple method that can be used to sex live zebrafish at the pubertal stage and provides the first evidence for the relationship of BTs and male puberty initiation with body growth. These findings will accordingly lay a foundation for exploring mechanisms of the SSCs and male puberty onset in zebrafish and other teleost fish. 相似文献
958.
Shao-guang Huang Le-le Zhang Qin Niu Gui-ming Xiang Lin-lin Liu Dong-neng Jiang Fei Liu Yi Li Xiaoyun Pu 《PloS one》2013,8(10)
Glioma pathogenesis related-2 (GLIPR-2) belongs to pathogenesis related-1 (PR-1) family whose function remains unknown. In our previous studies, GLIPR-2 was found to be a novel potent stimulator of epithelial-to-mesenchymal transition (EMT) in renal fibrosis which has been classified as type 2 EMT. However, whether GLIPR-2 could induce type 3 EMT in carcinogenesis needs further investigation. In this study, we showed that GLIPR-2 was expressed in hepatocellular carcinoma (HCC) tissues, hypoxia could upregulate the expression of GLIPR-2 in HepG2 and PLC/PRF/5 cells in vitro, overexpression of this protein promoted migration and invasion via EMT, knockdown of GLIPR-2 attenuated migration and invasion of HepG2 and PLC/PRF/5 cells in hypoxia. Moreover, extracellular signal-regulated kinases 1 and 2 (ERK1/2) are positively regulated by GLIPR-2. Taken together, we provide evidence for a hypoxia/GLIPR-2/EMT/migration and invasion axis in HCC cells and it provides novel insights into the mechanism of migration and invasion of hepatocellular carcinoma cells in hypoxia condition. 相似文献
959.
Kai-Ming T. Pu Parid Sava Anjelica L. Gonzalez 《The Yale journal of biology and medicine》2013,86(4):537-554
Fibrosis is characterized by excessive extracellular matrix deposition and is the
pathological outcome of repetitive tissue injury in many disorders. The
accumulation of matrix disrupts the structure and function of the native tissue
and can affect multiple organs including the lungs, heart, liver, and skin.
Unfortunately, current therapies against the deadliest and most common fibrosis
are ineffective. The pathogenesis of fibrosis is the result of aberrant wound
healing, therefore, the microvasculature plays an important role, contributing
through regulation of leukocyte recruitment, inflammation, and angiogenesis.
Further exacerbating the condition, microvascular endothelial cells and
pericytes can transdifferentiate into matrix depositing myofibroblasts. The
contribution of the microvasculature to fibrotic progression makes its cellular
components and acellular products attractive therapeutic targets. In this
review, we examine many of the cytokine, matrix, and cellular microvascular
components involved in fibrosis and discuss their potential as targets for
fibrotic therapies with a particular focus on developing nanotechnologies. 相似文献
960.
Su-Feng Zhao Ping Zhan Xu-Dong Yang Ming-Xing Lu Guo-Wen Sun Yu-Xin Wang Yin-Kai Zhang Yu-Mei Pu En-Yi Tang 《Molecular biology reports》2013,40(12):6637-6643
Many studies have examined the association between the VEGF +936C/T (rs833061) and +460C/T (rs3025039) gene polymorphisms and oral cancer risk in various populations, but their results have been inconsistent. To assess this relationship more precisely, we performed a meta-analysis. The PubMed, Embase, Web of Science, and China National Knowledge Infrastructure databases were searched for case–control studies that were published up to January 2013. Data were extracted and pooled odds ratios (ORs) with 95 % confidence intervals (CIs) were calculated. Ultimately, six studies were included, comprising 1006 oral cancer cases and 1016 controls. Overall, the pooled OR for VEGF +936 T allele carriers (TC + TT) versus the wild-type homozygotes (CC) was 1.28 (95 % CI 1.04–1.58; P = 0.228 for heterogeneity), the pooled OR for TT versus CC was 1.64 (95 % CI 1.34–1.98; P = 0.315 for heterogeneity), and the pooled OR for the T allele versus the C allele was 1.42 (95 % CI 1.22–1.76; P = 0.286 for heterogeneity). In the stratified analysis by ethnicity, significant risks were found among Caucasians but not Asians. However, there were no associations between VEGF +460C/T and oral cancer risk in only two of the included studies. In conclusion, this meta-analysis demonstrates that the VEGF +936 T allele may be associated with an increased risk of oral cancer, especially among Caucasian populations. 相似文献