全文获取类型
收费全文 | 54658篇 |
免费 | 4238篇 |
国内免费 | 4346篇 |
专业分类
63242篇 |
出版年
2024年 | 132篇 |
2023年 | 695篇 |
2022年 | 1652篇 |
2021年 | 2954篇 |
2020年 | 1904篇 |
2019年 | 2394篇 |
2018年 | 2355篇 |
2017年 | 1621篇 |
2016年 | 2288篇 |
2015年 | 3367篇 |
2014年 | 3981篇 |
2013年 | 4264篇 |
2012年 | 5029篇 |
2011年 | 4464篇 |
2010年 | 2789篇 |
2009年 | 2366篇 |
2008年 | 2777篇 |
2007年 | 2453篇 |
2006年 | 2242篇 |
2005年 | 1912篇 |
2004年 | 1536篇 |
2003年 | 1339篇 |
2002年 | 1110篇 |
2001年 | 948篇 |
2000年 | 858篇 |
1999年 | 892篇 |
1998年 | 513篇 |
1997年 | 507篇 |
1996年 | 520篇 |
1995年 | 442篇 |
1994年 | 470篇 |
1993年 | 354篇 |
1992年 | 411篇 |
1991年 | 348篇 |
1990年 | 290篇 |
1989年 | 256篇 |
1988年 | 174篇 |
1987年 | 151篇 |
1986年 | 129篇 |
1985年 | 112篇 |
1984年 | 85篇 |
1983年 | 70篇 |
1982年 | 46篇 |
1981年 | 18篇 |
1980年 | 9篇 |
1979年 | 13篇 |
1976年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
Yihao Yang Ziyan Shen Youguang Li Chenda Xu Han Xia Hao Zhuang Shengyuan Sun Min Guo Changjie Yan 《植物学报(英文版)》2022,64(10):1860-1865
Rice eating and cooking quality(ECQ) is a major concern of breeders and consumers, determining market competitiveness worldwide. Rice grain protein content(GPC) is negatively related to ECQ,making it possible to improve ECQ by manipulating GPC. However, GPC is genetically complex and sensitive to environmental conditions; therefore, little progress has been made in traditional breeding for ECQ. Here, we report that CRISPR/Cas9-mediated knockout of genes encoding the grain storage protein gluteli... 相似文献
112.
Jun Ma Qiang Li Lei Zhang Sen Cai Yuanyuan Liu Juncheng Lin Rongfeng Huang Yongqiang Yu Mingzhang Wen Tongda Xu 《植物学报(英文版)》2022,64(12):2425-2437
Callus induction,which results in fate transition in plant cells,is considered as the first and key step for plant regeneration.This process can be stimulated in different tissues by a callus-inducing medium(CIM),which contains a high concentration of phytohormone auxin.Although a few key regulators for callus induction have been identified,the multiple aspects of the regulatory mechanism driven by high levels of auxin still need further investigation.Here,we find that high auxin induces callus ... 相似文献
113.
114.
Yiwen Liu Jianfang Gao Min Xu Qianqian Zhou Zhongxiao Zhang Jiaxin Ye Rui Li 《Journal of cellular and molecular medicine》2022,26(13):3616
Congenital heart disease (CHD) is the most common birth defect, affecting approximately 1% of live births. Genetic and environmental factors are leading factors to CHD, but the mechanism of CHD pathogenesis remains unclear. Circular RNAs (circRNAs) are kinds of endogenous non‐coding RNAs (ncRNAs) involved in a variety of physiological and pathological processes, especially in heart diseases. In this study, three significant differently expressed circRNA between maternal embryonic day (E) E13 and E17 was found by microarray assay. Among them, the content of circ‐RCCD increases with the development of heart and was enriched in primary cardiomyocytes of different species, which arouses our attention. Functional experiments revealed that inhibition of circ‐RCCD dramatically suppressed the formation of beating cell clusters, the fluorescence intensity of cardiac differentiation marker MF20, and the expression of the myocardial‐specific markers CTnT, Mef2c, and GATA4. Next, we found that circ‐RCCD was involved in cardiomyocyte differentiation through negative regulation of MyD88 expression. Further experiments proved that circ‐RCCD inhibited MyD88 levels by recruiting YY1 to the promoter of MyD88; circ‐RCCD inhibited nuclear translocation of YY1. These results reported that circ‐RCCD promoted cardiomyocyte differentiation by recruiting YY1 to the promoter of MyD88. And, this study provided a potential role and molecular mechanism of circ‐RCCD as a target for the treatment of CHD. 相似文献
115.
116.
117.
富营养化河水灌溉对稻田土壤氮磷养分贡献的影响——以太湖地区黄泥土为例 总被引:7,自引:1,他引:6
以太湖地区主要稻田土壤类型黄泥土为对象,利用当地富营养化河水对回填土柱和植稻原状土渗漏池进行模拟稻田灌溉试验,系统研究了灌溉水对稻田土壤氮磷营养的贡献.在回填土柱灌溉试验中,在试验初期,不同形态的氮素均有较高的淋失量,以后逐渐降低,表明初期淋失的氮素主要来自土壤,而不是灌溉河水.在整个水稻生长季,均观测到有可溶性有机氮淋失,表明富营养化河水灌溉条件下可溶性有机氮是稻田土壤主要的氮素淋失形态.在本试验中,磷素的淋失动态与氮素的淋失动态截然相反,淹水后很长一段时间内均没有土壤磷素淋失,但在淹水灌溉后期有大量的土壤磷素淋失损失,这可能是淹水后期土壤对磷的吸持已达到饱和状态,不能继续固持土壤中多余的磷所致.与回填土柱模拟灌溉淋洗试验相比,在当前供肥条件下,原状土渗漏池试验氮磷淋失量远低于回填土柱试验,而灌溉水对土壤氮磷养分的贡献远高于回填土柱.通过富营养化河水灌溉带入当季稻田的N量达到每公顷56.3 kg,其中有55.8 kg N可被土壤吸持和作物吸收,表明太湖地区稻田土壤对氮磷养分来说是一个环境友好的生态系统.在利用当地富营养化河水进行稻田土壤灌溉时可适量减少肥料施用量、优化氮磷肥料管理. 相似文献
118.
为实现高通量识别新的药物-长链非编码RNA(Long non-coding RNA, lncRNA)关联,本文提出了一种基于图卷积网络模型来识别潜在药物-lncRNA关联的方法DLGCN(Drug-LncRNA graph convolution network)。首先,基于药物的结构信息和lncRNA的序列信息分别构建了药物-药物和lncRNA-lncRNA相似性网络,并整合实验证实的药物-lncRNA关联构建了药物-lncRNA异质性网络。然后,将注意力机制和图卷积运算应用于该网络中,学习药物和lncRNA的低维特征,基于整合的低维特征预测新的药物-lncRNA关联。通过效能评估,DLGCN的受试者工作特性曲线下面积(Area under receiver operating characteristic, AUROC)达到0.843 1,优于经典的机器学习方法和常见的深度学习方法。此外,DLGCN预测到姜黄素能够调控lncRNA MALAT1的表达,已被最近的研究证实。DLGCN能够有效预测药物-lncRNA关联,为肿瘤治疗新靶点的识别和抗癌药物的筛选提供了重要参考。 相似文献
119.
Human C1orf27 protein interacts with α2A-adrenergic receptor and regulates its anterograde transport
The molecular mechanisms underlying the anterograde surface transport of G protein–coupled receptors (GPCRs) after their synthesis in the endoplasmic reticulum (ER) are not well defined. In C. elegans, odorant response abnormal 4 has been implicated in the delivery of olfactory GPCRs to the cilia of chemosensory neurons. However, the function and regulation of its human homolog, C1orf27, in GPCR transport or in general membrane trafficking remain unknown. Here, we demonstrate that siRNA-mediated knockdown of C1orf27 markedly impedes the ER-to-Golgi export kinetics of newly synthesized α2A-adrenergic receptor (α2A-AR), a prototypic GPCR, with the half-time being prolonged by more than 65%, in mammalian cells in retention using the selective hooks assays. Using modified bioluminescence resonance energy transfer assays and ELISAs, we also show that C1orf27 knockdown significantly inhibits the surface transport of α2A-AR. Similarly, C1orf27 knockout by CRISPR-Cas9 markedly suppresses the ER–Golgi-surface transport of α2A-AR. In addition, we demonstrate that C1orf27 depletion attenuates the export of β2-AR and dopamine D2 receptor but not of epidermal growth factor receptor. We further show that C1orf27 physically associates with α2A-AR, specifically via its third intracellular loop and C terminus. Taken together, these data demonstrate an important role of C1orf27 in the trafficking of nascent GPCRs from the ER to the cell surface through the Golgi and provide novel insights into the regulation of the biosynthesis and anterograde transport of the GPCR family members. 相似文献
120.
LRG‐1 promotes fat graft survival through the RAB31‐mediated inhibition of hypoxia‐induced apoptosis
Chiakang Ho Danning Zheng Jiaming Sun Dongsheng Wen Shan Wu Li Yu Ya Gao Yifan Zhang Qingfeng Li 《Journal of cellular and molecular medicine》2022,26(11):3153
Autologous adipose tissue is an ideal soft tissue filling material, and its biocompatibility is better than that of artificial tissue substitutes, foreign bodies and heterogeneous materials. Although autologous fat transplantation has many advantages, the low retention rate of adipose tissue limits its clinical application. Here, we identified a secretory glycoprotein, leucine‐rich‐alpha‐2‐glycoprotein 1 (LRG‐1), that could promote fat graft survival through RAB31‐mediated inhibition of hypoxia‐induced apoptosis. We showed that LRG‐1 injection significantly increased the maintenance of fat volume and weight compared with the control. In addition, higher fat integrity, more viable adipocytes and fewer apoptotic cells were observed in the LRG‐1‐treated groups. Furthermore, we discovered that LRG‐1 could reduce the ADSC apoptosis induced by hypoxic conditions. The mechanism underlying the LRG‐1‐mediated suppression of the ADSC apoptosis induced by hypoxia was mediated by the upregulation of RAB31 expression. Using LRG‐1 for fat grafts may prove to be clinically successful for increasing the retention rate of transplanted fat. 相似文献