全文获取类型
收费全文 | 1461篇 |
免费 | 143篇 |
国内免费 | 60篇 |
专业分类
1664篇 |
出版年
2024年 | 5篇 |
2023年 | 24篇 |
2022年 | 46篇 |
2021年 | 75篇 |
2020年 | 47篇 |
2019年 | 52篇 |
2018年 | 56篇 |
2017年 | 35篇 |
2016年 | 55篇 |
2015年 | 91篇 |
2014年 | 105篇 |
2013年 | 103篇 |
2012年 | 123篇 |
2011年 | 125篇 |
2010年 | 59篇 |
2009年 | 57篇 |
2008年 | 74篇 |
2007年 | 58篇 |
2006年 | 46篇 |
2005年 | 59篇 |
2004年 | 37篇 |
2003年 | 34篇 |
2002年 | 27篇 |
2001年 | 19篇 |
2000年 | 27篇 |
1999年 | 29篇 |
1998年 | 7篇 |
1997年 | 14篇 |
1996年 | 21篇 |
1995年 | 9篇 |
1994年 | 16篇 |
1993年 | 3篇 |
1992年 | 19篇 |
1991年 | 10篇 |
1990年 | 16篇 |
1989年 | 12篇 |
1988年 | 12篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有1664条查询结果,搜索用时 15 毫秒
51.
Liang Guo Jia-Xin Huang Yuan Liu Xi Li Shui-Rong Zhou Shu-Wen Qian Yang Liu Hao Zhu Hai-Yan Huang Yong-Jun Dang Qi-Qun Tang 《Molecular and cellular biology》2013,33(16):3180-3190
Autophagy is a highly conserved self-digestion pathway involved in various physiological and pathophysiological processes. Recent studies have implicated a pivotal role of autophagy in adipocyte differentiation, but the molecular mechanism for its role and how it is regulated during this process are not clear. Here, we show that CCAAT /enhancer-binding protein β (C/EBPβ), an important adipogenic factor, is required for the activation of autophagy during 3T3-L1 adipocyte differentiation. An autophagy-related gene, Atg4b, is identified as a de novo target gene of C/EBPβ and is shown to play an important role in 3T3-L1 adipocyte differentiation. Furthermore, autophagy is required for the degradation of Klf2 and Klf3, two negative regulators of adipocyte differentiation, which is mediated by the adaptor protein p62/SQSTM1. Importantly, the regulation of autophagy by C/EBPβ and the role of autophagy in Klf2/3 degradation and in adipogenesis are further confirmed in mouse models. Our data describe a novel function of C/EBPβ in regulating autophagy and reveal the mechanism of autophagy during adipocyte differentiation. These new insights into the molecular mechanism of adipose tissue development provide a functional pathway with therapeutic potential against obesity and its related metabolic disorders. 相似文献
52.
Can Chen Yi Wang Sally S. L. Goh Jing Yang Dang Hoang Lam Yukti Choudhury Felix Chang Tay Shouhui Du Wee Kiat Tan Yovita Ida Purwanti Weimin Fan Shu Wang 《Journal of neurochemistry》2013,126(3):318-330
The breakthrough in derivation of human‐induced pluripotent stem cells (hiPSCs) provides an approach that may help overcome ethical and allergenic challenges posed in numerous medical applications involving human cells, including neural stem/progenitor cells (NSCs). Considering the great potential of NSCs in targeted cancer gene therapy, we investigated in this study the tumor tropism of hiPSC‐derived NSCs and attempted to enhance the tropism by manipulation of biological activities of proteins that are involved in regulating the migration of NSCs toward cancer cells. We first demonstrated that hiPSC‐NSCs displayed tropism for both glioblastoma cells and breast cancer cells in vitro and in vivo. We then compared gene expression profiles between migratory and non‐migratory hiPSC‐NSCs toward these cancer cells and observed that the gene encoding neuronal nitric oxide synthase (nNOS) was down‐regulated in migratory hiPSC‐NSCs. Using nNOS inhibitors and nNOS siRNAs, we demonstrated that this protein is a relevant regulator in controlling migration of hiPSC‐NSCs toward cancer cells, and that inhibition of its activity or down‐regulation of its expression can sensitize poorly migratory NSCs and be used to improve their tumor tropism. These findings suggest a novel application of nNOS inhibitors in neural stem cell‐mediated cancer therapy. 相似文献
53.
Dang Lelamurni Abd Razak Noorlidah Abdullah Norjuliza Mohd Khir Johari Vikineswary Sabaratnam 《Applied microbiology and biotechnology》2013,97(7):3207-3213
The potential for using agricultural and industrial by-products as substrate for the production of the edible mushroom, Auricularia polytricha, was evaluated using several formulations of selected palm oil wastes mixed with sawdust and further supplemented with selected nitrogen sources. The best substrate formulations were sawdust (SD) mixed with oil palm frond (OPF; 90:10) added with 15 % spent grain (SG) and sawdust mixed with empty fruit bunch (EFB; 50:50) added with 10 % spent grain (SG) with mycelia growth rate of 8 mm/day and 7 mm/day respectively. These two substrate formulations were then subjected to different moisture content levels (65 %, 75 % and 85 %). Highest total fresh sporophore yield at 0.43 % was obtained on SD?+?OPF (90:10)?+?15 % SG at 85 % moisture content, followed closely by SD?+?EFB (50:50)?+?10 % SG with 0.40 % total yield, also at 85 % moisture content. Each of the substrate formulations at 85 % moisture content gave the highest biological efficiency (BE) at 288.9 % and 260.7 %, respectively. Both yield and biological efficiency of A. polytricha on these two formulations were almost three times higher when compared to sawdust substrate alone, thus proving the potential of these formulations to improve yield of this mushroom. 相似文献
54.
Qiao Sun Yiwu Yao Chunping Liu Hua Li Hequan Yao Xiaowen Xue Jinsong Liu Zhengchao Tu Sheng Jiang 《Bioorganic & medicinal chemistry letters》2013,23(11):3295-3299
We report the design, synthesis, and biological evaluation of a new series of HDAC1 inhibitors using click chemistry. Compound 17 bearing a phenyl ring at meta-position was identified to show much better selectivity for HDAC1 over HDAC7 than SAHA. The compond 17 also showed better in vitro anticancer activities against several cancer cell lines than that of SAHA. This work could serve as a foundation for further exploration of selective HDAC inhibitors using the compound 17 molecular scaffold. 相似文献
55.
56.
57.
58.
3-Hydroxy-4(4H)-pyridone (3,4-DHP), a degraded product of mimosine [β-[N-(3-hydroxy-4-oxypyridyl)]-α-aminopropionic acid], is known to cause goiters, loss of hair, and infertility in animals, but limits of 3,4-DHP on separation and purification have prevented efforts on investigating other toxicity and biological properties of 3,4-DHP. By this study, a novel and simple isolation of 3,4-DHP was developed either from Leucaena leaves using an ion-exchanged resin or mimosine degraded in high temperature (110°C, 6?h). The inhibition of mimosine on the growth of barnyardgrass was approximately fourfold higher (IC50?=?0.04?mg?g?1) than that of 3,4-DHP (IC50?=?0.15?mg?g?1). In general, the antifungal activity of mimosine is much stronger than that of 3,4-DHP, but it differs depending on the kind of fungi. The 1,1-diphyenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of 3,4-DHP, in contrast with the growth inhibitory activity, is about fourfold stronger [EC50?=?2.4?mg?g?1 gallic acid equivalent (GAE)] than that of mimosine [EC50?=?10.3?mg?g?1 GAE]. This study is the first to report on the herbicidal, antifungal, and antioxidant activities of 3,4-DHP. 相似文献
59.
MicroRNAs (miRNAs) are endogenous small noncoding RNA molecules that negatively regulate gene expression. Herein, we investigated a selective number of miRNAs for their expression in skin tissue of Liaoning Cashmere goat during hair follicle cycles, and their intracellular regulatory networks were constructed based on bioinformatics analysis. The relative expression of six miRNAs (mir-103-3p, -15b-5p, 17-5p, -200b, -25-3p, and -30c-5p) at anagen phase is significantly higher than that at catagen and/or telogen phases. In comparison to anagen, the relative expression of seven miRNAs (mir-148a-3p, -199a-3p, -199a-5p, -24-3p, -30a-5p, -30e-5p, and -29a-3p) was revealed to be significantly up-regulated at catagen and/or telogen stages. The network analyses of miRNAs indicated those miRNAs investigated might be directly or indirectly involved in several signaling pathways through their target genes. These results provided a foundation for further insight into the roles of these miRNAs in skin tissue of Liaoning Cashmere goat during hair follicle cycles. 相似文献
60.
Caws M Dang TM Torok E Campbell J Do DA Tran TH Nguyen vV Nguyen TC Farrar J 《PloS one》2007,2(11):e1173