全文获取类型
收费全文 | 6921篇 |
免费 | 491篇 |
国内免费 | 1篇 |
出版年
2023年 | 38篇 |
2022年 | 105篇 |
2021年 | 186篇 |
2020年 | 138篇 |
2019年 | 164篇 |
2018年 | 210篇 |
2017年 | 160篇 |
2016年 | 284篇 |
2015年 | 452篇 |
2014年 | 441篇 |
2013年 | 582篇 |
2012年 | 662篇 |
2011年 | 628篇 |
2010年 | 347篇 |
2009年 | 313篇 |
2008年 | 394篇 |
2007年 | 369篇 |
2006年 | 337篇 |
2005年 | 305篇 |
2004年 | 265篇 |
2003年 | 214篇 |
2002年 | 235篇 |
2001年 | 44篇 |
2000年 | 30篇 |
1999年 | 43篇 |
1998年 | 55篇 |
1997年 | 30篇 |
1996年 | 34篇 |
1995年 | 23篇 |
1994年 | 30篇 |
1993年 | 23篇 |
1992年 | 28篇 |
1991年 | 17篇 |
1990年 | 15篇 |
1989年 | 15篇 |
1988年 | 12篇 |
1987年 | 13篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 14篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 8篇 |
1980年 | 14篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 6篇 |
1974年 | 7篇 |
1973年 | 15篇 |
排序方式: 共有7413条查询结果,搜索用时 31 毫秒
231.
Transcriptional reprogramming underpins enhanced plant growth promotion by the biocontrol fungus Trichoderma hamatum GD12 during antagonistic interactions with Sclerotinia sclerotiorum in soil 下载免费PDF全文
232.
Arik Kershenbaum Daniel T. Blumstein Marie A. Roch Çağlar Akçay Gregory Backus Mark A. Bee Kirsten Bohn Yan Cao Gerald Carter Cristiane Cäsar Michael Coen Stacy L. DeRuiter Laurance Doyle Shimon Edelman Ramon Ferrer‐i‐Cancho Todd M. Freeberg Ellen C. Garland Morgan Gustison Heidi E. Harley Chloé Huetz Melissa Hughes Julia Hyland Bruno Amiyaal Ilany Dezhe Z. Jin Michael Johnson Chenghui Ju Jeremy Karnowski Bernard Lohr Marta B. Manser Brenda McCowan Eduardo Mercado III Peter M. Narins Alex Piel Megan Rice Roberta Salmi Kazutoshi Sasahara Laela Sayigh Yu Shiu Charles Taylor Edgar E. Vallejo Sara Waller Veronica Zamora‐Gutierrez 《Biological reviews of the Cambridge Philosophical Society》2016,91(1):13-52
Animal acoustic communication often takes the form of complex sequences, made up of multiple distinct acoustic units. Apart from the well‐known example of birdsong, other animals such as insects, amphibians, and mammals (including bats, rodents, primates, and cetaceans) also generate complex acoustic sequences. Occasionally, such as with birdsong, the adaptive role of these sequences seems clear (e.g. mate attraction and territorial defence). More often however, researchers have only begun to characterise – let alone understand – the significance and meaning of acoustic sequences. Hypotheses abound, but there is little agreement as to how sequences should be defined and analysed. Our review aims to outline suitable methods for testing these hypotheses, and to describe the major limitations to our current and near‐future knowledge on questions of acoustic sequences. This review and prospectus is the result of a collaborative effort between 43 scientists from the fields of animal behaviour, ecology and evolution, signal processing, machine learning, quantitative linguistics, and information theory, who gathered for a 2013 workshop entitled, ‘Analysing vocal sequences in animals’. Our goal is to present not just a review of the state of the art, but to propose a methodological framework that summarises what we suggest are the best practices for research in this field, across taxa and across disciplines. We also provide a tutorial‐style introduction to some of the most promising algorithmic approaches for analysing sequences. We divide our review into three sections: identifying the distinct units of an acoustic sequence, describing the different ways that information can be contained within a sequence, and analysing the structure of that sequence. Each of these sections is further subdivided to address the key questions and approaches in that area. We propose a uniform, systematic, and comprehensive approach to studying sequences, with the goal of clarifying research terms used in different fields, and facilitating collaboration and comparative studies. Allowing greater interdisciplinary collaboration will facilitate the investigation of many important questions in the evolution of communication and sociality. 相似文献
233.
The rat ErbB2 tyrosine kinase receptor produced in plants is immunogenic in mice and confers protective immunity against ErbB2+ mammary cancer 下载免费PDF全文
Slavica Matić Elena Quaglino Lucia Arata Federica Riccardo Mattia Pegoraro Marta Vallino Federica Cavallo Emanuela Noris 《Plant biotechnology journal》2016,14(1):153-159
The rat ErbB2 (rErbB2) protein is a 185‐kDa glycoprotein belonging to the epidermal growth factor‐related proteins (ErbB) of receptor tyrosine kinases. Overexpression and mutations of ErbB proteins lead to several malignancies including breast, lung, pancreatic, bladder and ovary carcinomas. ErbB2 is immunogenic and is an ideal candidate for cancer immunotherapy. We investigated the possibility of expressing the extracellular (EC) domain of rErbB2 (653 amino acids, aa) in Nicotiana benthamiana plants, testing the influence of the 23 aa transmembrane (TM) sequence on protein accumulation. Synthetic variants of the rErbB2 gene portion encoding the EC domain, optimized with a human codon usage and either linked to the full TM domain (rErbB2_TM, 676 aa), to a portion of it (rErbB2‐pTM, 662 aa), or deprived of it (rErbB2_noTM, 653 aa) were cloned in the pEAQ‐HT expression vector as 6X His tag fusions. All rErbB2 variants (72–74.5 kDa) were transiently expressed, but the TM was detrimental for rErbB2 EC accumulation. rERbB2_noTM was the most expressed protein; it was solubilized and purified with Nickel affinity resin. When crude soluble extracts expressing rErbB2_noTM were administered to BALB/c mice, specific rErbB2 immune responses were triggered. A potent antitumour activity was induced when vaccinated mice were challenged with syngeneic transplantable ErbB2+ mammary carcinoma cells. To our knowledge, this is the first report of expression of rErbB2 in plants and of its efficacy in inducing a protective antitumour immune response, opening interesting perspectives for further immunological testing. 相似文献
234.
Marc D Tambini Marta Pera Ellen Kanter Hua Yang Cristina Guardia‐Laguarta David Holtzman David Sulzer Estela Area‐Gomez Eric A Schon 《EMBO reports》2016,17(1):27-36
In addition to the appearance of senile plaques and neurofibrillary tangles, Alzheimer''s disease (AD) is characterized by aberrant lipid metabolism and early mitochondrial dysfunction. We recently showed that there was increased functionality of mitochondria‐associated endoplasmic reticulum (ER) membranes (MAM), a subdomain of the ER involved in lipid and cholesterol homeostasis, in presenilin‐deficient cells and in fibroblasts from familial and sporadic AD patients. Individuals carrying the ε4 allele of apolipoprotein E (ApoE4) are at increased risk for developing AD compared to those carrying ApoE3. While the reason for this increased risk is unknown, we hypothesized that it might be associated with elevated MAM function. Using an astrocyte‐conditioned media (ACM) model, we now show that ER–mitochondrial communication and MAM function—as measured by the synthesis of phospholipids and of cholesteryl esters, respectively—are increased significantly in cells treated with ApoE4‐containing ACM as compared to those treated with ApoE3‐containing ACM. Notably, this effect was seen with lipoprotein‐enriched preparations, but not with lipid‐free ApoE protein. These data are consistent with a role of upregulated MAM function in the pathogenesis of AD and may help explain, in part, the contribution of ApoE4 as a risk factor in the disease. 相似文献
235.
236.
237.
Marta I. Sánchez Inès Pons Mónica Martínez-Haro Mark A. Taggart Thomas Lenormand Andy J. Green 《PLoS pathogens》2016,12(3)
Parasites and pollutants can both affect any living organism, and their interactions can be very important. To date, repeated studies have found that parasites and heavy metals or metalloids both have important negative effects on the health of animals, often in a synergistic manner. Here, we show for the first time that parasites can increase host resistance to metalloid arsenic, focusing on a clonal population of brine shrimp from the contaminated Odiel and Tinto estuary in SW Spain. We studied the effect of cestodes on the response of Artemia to arsenic (acute toxicity tests, 24h LC50) and found that infection consistently reduced mortality across a range of arsenic concentrations. An increase from 25°C to 29°C, simulating the change in mean temperature expected under climate change, increased arsenic toxicity, but the benefits of infection persisted. Infected individuals showed higher levels of catalase and glutathione reductase activity, antioxidant enzymes with a very important role in the protection against oxidative stress. Levels of TBARS were unaffected by parasites, suggesting that infection is not associated with oxidative damage. Moreover, infected Artemia had a higher number of carotenoid-rich lipid droplets which may also protect the host through the “survival of the fattest” principle and the antioxidant potential of carotenoids. This study illustrates the need to consider the multi-stress context (contaminants and temperature increase) in which host-parasite interactions occur. 相似文献
238.
Simon P. Fletcher Daniel J. Chin Lore Gruenbaum Hans Bitter Erik Rasmussen Palanikumar Ravindran David C. Swinney Fabian Birzele Roland Schmucki Stefan H. Lorenz Erhard Kopetzki Jade Carter Miriam Triyatni Linta M. Thampi Junming Yang Dalal AlDeghaither Marta G. Murreddu Paul Cote Stephan Menne 《PLoS pathogens》2016,12(3)
239.
Xudong Liu Chuan-En Wang Yan Hong Ting Zhao Guohao Wang Marta A. Gaertig Miao Sun Shihua Li Xiao-Jiang Li 《PLoS genetics》2016,12(5)
The Huntington’s disease (HD) protein, huntingtin (HTT), is a large protein consisting of 3144 amino acids and has conserved N-terminal sequences that are followed by a polyglutamine (polyQ) repeat. Loss of Htt is known to cause embryonic lethality in mice, whereas polyQ expansion leads to adult neuronal degeneration. Whether N-terminal HTT is essential for neuronal development or contributes only to late-onset neurodegeneration remains unknown. We established HTT knock-in mice (N160Q-KI) expressing the first 208 amino acids of HTT with 160Q, and they show age-dependent HTT aggregates in the brain and neurological phenotypes. Importantly, the N-terminal mutant HTT also preferentially accumulates in the striatum, the brain region most affected in HD, indicating the importance of N-terminal HTT in selective neuropathology. That said, homozygous N160Q-KI mice are also embryonic lethal, suggesting that N-terminal HTT alone is unable to support embryonic development. Using Htt knockout neurons, we found that loss of Htt selectively affects the survival of developing neuronal cells, but not astrocytes, in culture. This neuronal degeneration could be rescued by a truncated HTT lacking the first 237 amino acids, but not by N-terminal HTT (1–208 amino acids). Also, the rescue effect depends on the region in HTT known to be involved in intracellular trafficking. Thus, the N-terminal HTT region may not be essential for the survival of developing neurons, but when carrying a large polyQ repeat, can cause selective neuropathology. These findings imply a possible therapeutic benefit of removing the N-terminal region of HTT containing the polyQ repeat to treat the neurodegeneration in HD. 相似文献
240.
Marta Boccazzi Davide Lecca Davide Marangon Fabio Guagnini Maria P. Abbracchio Stefania Ceruti 《Purinergic signalling》2016,12(4):661-672
Oligodendrocyte precursor cells (OPCs, also called NG2 cells) are scattered throughout brain parenchyma, where they function as a reservoir to replace lost or damaged oligodendrocytes, the myelin-forming cells. The hypothesis that, under some circumstances, OPCs can actually behave as multipotent cells, thus generating astrocytes and neurons as well, has arisen from some in vitro and in vivo evidence, but the molecular pathways controlling this alternative fate of OPCs are not fully understood. Their identification would open new opportunities for neuronal replace strategies, by fostering the intrinsic ability of the brain to regenerate. Here, we show that the anti-epileptic epigenetic modulator valproic acid (VPA) can promote the generation of new neurons from NG2+ OPCs under neurogenic protocols in vitro, through their initial de-differentiation to a stem cell-like phenotype that then evolves to “hybrid” cell population, showing OPC morphology but expressing the neuronal marker βIII-tubulin and the GPR17 receptor, a key determinant in driving OPC transition towards myelinating oligodendrocytes. Under these conditions, the pharmacological blockade of the P2Y-like receptor GPR17 by cangrelor, a drug recently approved for human use, partially mimics the effects mediated by VPA thus accelerating cells’ neurogenic conversion. These data show a co-localization between neuronal markers and GPR17 in vitro, and suggest that, besides its involvement in oligodendrogenesis, GPR17 can drive the fate of neural precursor cells by instructing precursors towards the neuronal lineage. Being a membrane receptor, GPR17 represents an ideal “druggable” target to be exploited for innovative regenerative approaches to acute and chronic brain diseases. 相似文献