全文获取类型
收费全文 | 9660篇 |
免费 | 710篇 |
国内免费 | 805篇 |
出版年
2024年 | 14篇 |
2023年 | 119篇 |
2022年 | 332篇 |
2021年 | 628篇 |
2020年 | 355篇 |
2019年 | 470篇 |
2018年 | 463篇 |
2017年 | 318篇 |
2016年 | 447篇 |
2015年 | 683篇 |
2014年 | 792篇 |
2013年 | 780篇 |
2012年 | 922篇 |
2011年 | 850篇 |
2010年 | 496篇 |
2009年 | 448篇 |
2008年 | 496篇 |
2007年 | 414篇 |
2006年 | 325篇 |
2005年 | 265篇 |
2004年 | 232篇 |
2003年 | 241篇 |
2002年 | 197篇 |
2001年 | 147篇 |
2000年 | 113篇 |
1999年 | 128篇 |
1998年 | 72篇 |
1997年 | 68篇 |
1996年 | 63篇 |
1995年 | 50篇 |
1994年 | 36篇 |
1993年 | 25篇 |
1992年 | 39篇 |
1991年 | 22篇 |
1990年 | 21篇 |
1989年 | 37篇 |
1988年 | 14篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 21篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 2篇 |
1981年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
261.
Honglei Jia Jisheng Li Jingen Zhu Tingting Fan Dong Qian Yuelong Zhou Jiaojiao Wang Haiyun Ren Yun Xiang Lizhe An 《The Journal of biological chemistry》2013,288(45):32277-32288
Higher order actin filament structures are necessary for cytoplasmic streaming, organelle movement, and other physiological processes. However, the mechanism by which the higher order cytoskeleton is formed in plants remains unknown. In this study, we identified a novel actin-cross-linking protein family (named CROLIN) that is well conserved only in the plant kingdom. There are six isovariants of CROLIN in the Arabidopsis genome, with CROLIN1 specifically expressed in pollen. In vitro biochemical analyses showed that CROLIN1 is a novel actin-cross-linking protein with binding and stabilizing activities. Remarkably, CROLIN1 can cross-link actin bundles into actin networks. CROLIN1 loss of function induces pollen germination and pollen tube growth hypersensitive to latrunculin B. All of these results demonstrate that CROLIN1 may play an important role in stabilizing and remodeling actin filaments by binding to and cross-linking actin filaments. 相似文献
262.
263.
Jia Zhou Minmin Liu Aaron M. Fleming Cynthia J. Burrows Susan S. Wallace 《The Journal of biological chemistry》2013,288(38):27263-27272
The telomeric DNA of vertebrates consists of d(TTAGGG)n tandem repeats, which can form quadruplex DNA structures in vitro and likely in vivo. Despite the fact that the G-rich telomeric DNA is susceptible to oxidation, few biochemical studies of base excision repair in telomeric DNA and quadruplex structures have been done. Here, we show that telomeric DNA containing thymine glycol (Tg), 8-oxo-7,8-dihydroguanine (8-oxoG), guanidinohydantoin (Gh), or spiroiminodihydantoin (Sp) can form quadruplex DNA structures in vitro. We have tested the base excision activities of five mammalian DNA glycosylases (NEIL1, NEIL2, mNeil3, NTH1, and OGG1) on these lesion-containing quadruplex substrates and found that only mNeil3 had excision activity on Tg in quadruplex DNA and that the glycosylase exhibited a strong preference for Tg in the telomeric sequence context. Although Sp and Gh in quadruplex DNA were good substrates for mNeil3 and NEIL1, none of the glycosylases had activity on quadruplex DNA containing 8-oxoG. In addition, NEIL1 but not mNeil3 showed enhanced glycosylase activity on Gh in the telomeric sequence context. These data suggest that one role for Neil3 and NEIL1 is to repair DNA base damages in telomeres in vivo and that Neil3 and Neil1 may function in quadruplex-mediated cellular events, such as gene regulation via removal of damaged bases from quadruplex DNA. 相似文献
264.
Tyler Schwend Zhigang Jin Kai Jiang Brian J. Mitchell Jianhang Jia Jing Yang 《The Journal of biological chemistry》2013,288(45):32809-32820
265.
Ya Meng Yue Yong Guang Yang Hanqing Ding Zhiqin Fan Yifen Tang Jia Luo Zun‐Ji Ke 《Journal of neurochemistry》2013,126(6):805-818
Thiamine deficiency (TD) causes mild impairment of oxidative metabolism and region‐selective neuronal loss in the brain, which may be mediated by neuronal oxidative stress, endoplasmic reticulum (ER) stress, and neuroinflammation. TD‐induced brain damage is used to model neurodegenerative disorders, and the mechanism for the neuronal death is still unclear. We hypothesized that autophagy might be activated in the TD brain and play a protective role in TD‐induced neuronal death. Our results demonstrated that TD induced the accumulation of autophagosomes in thalamic neurons measured by transmission electron microscopy, and the up‐regulation of autophagic markers LC3‐II, Atg5, and Beclin1 as measured with western blotting. TD also increased the expression of autophagic markers and induced LC3 puncta in SH‐SY5Y neuroblastoma cells. TD‐induced expression of autophagic markers was reversed once thiamine was re‐administered. Both inhibition of autophagy by wortmannin and Beclin1 siRNA potentiated TD‐induced death of SH‐SY5Y cells. In contrast, activation of autophagy by rapamycin alleviated cell death induced by TD. Intraperitoneal injection of rapamycin stimulated neuronal autophagy and attenuated TD‐induced neuronal death and microglia activation in the submedial thalamus nucleus (SmTN). TD inhibited the phosphorylation of p70S6 kinase, suggesting mTOR/p70S6 kinase pathway was involved in the TD‐induced autophagy. These results suggest that autophagy is neuroprotective in response to TD‐induced neuronal death in the central nervous system. This opens a potential therapeutic avenue for neurodegenerative diseases caused by mild impairment of oxidative metabolism.
266.
Na Yu Peiwei Huangyang Xiaohan Yang Xiao Han Ruorong Yan Hongti Jia Yongfeng Shang Luyang Sun 《The Journal of biological chemistry》2013,288(27):19633-19642
267.
Zhao Shan Qinglin Han Jia Nie Xuezhi Cao Zuojia Chen Shuying Yin Yayi Gao Fang Lin Xiaohui Zhou Ke Xu Huimin Fan Zhikang Qian Bing Sun Jin Zhong Bin Li Andy Tsun 《The Journal of biological chemistry》2013,288(49):35093-35103
Although lysine methylation is classically known to regulate histone function, its role in modulating antiviral restriction factor activity remains uncharacterized. Interferon-induced transmembrane protein 3 (IFITM3) was found monomethylated on its lysine 88 residue (IFITM3-K88me1) to reduce its antiviral activity, mediated by the lysine methyltransferase SET7. Vesicular stomatitis virus and influenza A virus infection increased IFITM3-K88me1 levels by promoting the interaction between IFITM3 and SET7, suggesting that this pathway could be hijacked to support infection; conversely, IFN-α reduced IFITM3-K88me1 levels. These findings may have important implications in the design of therapeutics targeting protein methylation against infectious diseases. 相似文献
268.
Bing Bing Jia 《Ocean Development & International Law》2013,44(4):266-280
This article discusses the issue of treaty regimes in parallel to the United Nations Convention on the Law of the Sea in respect of peaceful settlement of disputes concerning the interpretation or application of the Convention. The duality in relevancy of such disputes to two treaties at the same time would have begged the question about which treaty should be applied to settle them, but UNCLOS has a clear, conflict-of-law style rules in place to address the question. Article 281(1) is one such rule, and, with its exclusionary effect, stands out as a super provision of the Convention. 相似文献
269.
Yue Shen Chongxi Liu Xiangjing Wang Junwei Zhao Feiyu Jia Yuqin Zhang Liang Wang Deguang Yang Wensheng Xiang 《Antonie van Leeuwenhoek》2013,103(2):293-298
A novel actinomycete, designated strain NEAU-M9T, was isolated from soybean root (Glycine max (L.) Merr) and characterized using a polyphasic approach. 16S rRNA gene sequence similarity studies showed that strain NEAU-M9T belonged to the genus Actinoplanes, being most closely related to Actinoplanes campanulatus DSM 43148T (98.85 %), Actinoplanes capillaceus DSM 44859T (98.70 %), Actinoplanes lobatus DSM 43150T (98.30 %), Actinoplanes auranticolor DSM 43031T (98.23 %) and Actinoplanes sichuanensis 03-723T (98.06 %); similarity to other type strains of the genus Actinoplanes ranged from 95.87 to 97.56 %. The neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that the isolate formed a distinct phyletic line with A. campanulatus DSM 43148T and A. capillaceus DSM 44859T. This branching pattern was also supported by the tree constructed with the maximum-likelihood method. However, the low level of DNA–DNA relatedness allowed the isolate to be differentiated from the above-mentioned two Actinoplanes species. Moreover, strain NEAU-M9T could also be distinguished from the most closely related species by morphological, physiological and characteristics. Therefore, it is proposed that strain NEAU-M9T represents a novel Actinoplanes species, Actinoplanes hulinensis sp. nov. The type strain of Actinoplanes hulinensis is NEAU-M9T (= CGMCC 4.7036T = DSM 45728T). 相似文献
270.
Xu-Hong Gao Sheng Gao Yu Zhou Hui-Lin Guan Yun-Jiao Zhang Man Jia Hua-Wei Huang Dong-Xu Yang Wen-Jun Li Shu-Kun Tang 《Antonie van Leeuwenhoek》2013,103(1):207-215
A Gram-positive, moderately halotolerant, rod-shaped bacterium, designated YIM 94025T, was isolated from a soil sample from a salt lake in Xinjiang province, north-west China. Strain YIM 94025T was observed to grow at 25–45 °C (optimum 37 °C), 0–22 % NaCl (optimum 2–10 %) and pH 6.0–9.0 (optimum pH 8.0). Phylogenetic analyses based on 16S rRNA gene sequences revealed that the organism belongs to the genus Tenuibacillus and exhibited sequence similarity of 98.0 % to the closest type strain, Tenuibacillus multivorans AS 1.3442T. The predominant menaquinone was found to be MK-7; the cell-wall peptidoglycan diamino acid was meso-diaminopimelic acid; the polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, an unidentified phospholipid and an unknown lipid; and the major fatty acids were found to contain iso-C15:0, anteiso-C15:0 and iso-C16:0. The chemotaxonomic characteristics of strain YIM 94025T are consistent with those of the genus Tenuibacillus. The level of DNA–DNA relatedness value between YIM 94025T and T. multivorans AS 1.3442T was 36.6 ± 4.5 %. The G+C content of the strain YIM 94025T was determined to be 38.5 %. Based on the comparative analysis of physiological, biochemical and chemotaxonomic data, as well as DNA–DNA hybridization results, the isolate is considered to represent a novel species of the genus Tenuibacillus, for which the name Tenuibacillus halotolerans sp. nov., is proposed, with the type strain of YIM 94025T (=CCTCC AB 2012860T = KCTC 33046T). 相似文献