全文获取类型
收费全文 | 4135篇 |
免费 | 332篇 |
国内免费 | 2篇 |
出版年
2023年 | 21篇 |
2022年 | 49篇 |
2021年 | 108篇 |
2020年 | 56篇 |
2019年 | 74篇 |
2018年 | 116篇 |
2017年 | 84篇 |
2016年 | 151篇 |
2015年 | 199篇 |
2014年 | 247篇 |
2013年 | 322篇 |
2012年 | 392篇 |
2011年 | 335篇 |
2010年 | 224篇 |
2009年 | 180篇 |
2008年 | 244篇 |
2007年 | 213篇 |
2006年 | 194篇 |
2005年 | 184篇 |
2004年 | 171篇 |
2003年 | 149篇 |
2002年 | 138篇 |
2001年 | 25篇 |
2000年 | 27篇 |
1999年 | 34篇 |
1998年 | 45篇 |
1997年 | 17篇 |
1996年 | 22篇 |
1995年 | 18篇 |
1994年 | 21篇 |
1993年 | 17篇 |
1992年 | 19篇 |
1991年 | 14篇 |
1990年 | 22篇 |
1989年 | 19篇 |
1988年 | 15篇 |
1987年 | 15篇 |
1985年 | 11篇 |
1984年 | 25篇 |
1983年 | 15篇 |
1982年 | 17篇 |
1981年 | 16篇 |
1980年 | 18篇 |
1979年 | 17篇 |
1978年 | 16篇 |
1977年 | 8篇 |
1973年 | 9篇 |
1968年 | 8篇 |
1964年 | 8篇 |
1962年 | 7篇 |
排序方式: 共有4469条查询结果,搜索用时 218 毫秒
931.
932.
Ana I. Manzano F. Javier Cañada Bárbara Cases Sofia Sirvent Irene Soria Oscar Palomares Enrique Fernández-Caldas Miguel Casanovas Jesús Jiménez-Barbero José L. Subiza 《Glycoconjugate journal》2016,33(1):93-101
Immunotherapy for treating IgE-mediated allergies requires high doses of the corresponding allergen. This may result in undesired side effects and, to avoid them, hypoallergenic allergens (allergoids) polymerized with glutaraldehyde are commonly used. Targeting allergoids to dendritic cells to enhance cell uptake may result in a more effective immunotherapy. Allergoids coupled to yeast mannan, as source of polymannoses, would be suitable for this purpose, since mannose-binding receptors are expressed on these cells. Conventional conjugation procedures of mannan to proteins use oxidized mannan to release reactive aldehydes able to bind to free amino groups in the protein; yet, allergoids lack these latter because their previous treatment with glutaraldehyde. The aim of this study was to obtain allergoids conjugated to mannan by an alternative approach based on just glutaraldehyde treatment, taking advantage of the mannoprotein bound to the polymannose backbone. Allergoid-mannan glycoconjugates were produced in a single step by treating with glutaraldehyde a defined mixture of allergens derived from Phleum pratense grass pollen and native mannan (non-oxidized) from Saccharomyces cerevisae. Analytical and structural studies, including 2D-DOSY and 1H-13C HSQC nuclear magnetic resonance spectra, demonstrated the feasibility of such an approach. The glycoconjugates obtained were polymers of high molecular weight showing a higher stability than the native allergen or the conventional allergoid without mannan. The allergoid-mannan glycoconjugates were hypoallergenic as detected by the IgE reactivity with sera from grass allergic patients, even with lower reactivity than conventional allergoid without mannan. Thus, stable hypoallergenic allergoids conjugated to mannan suitable for using in immunotherapy can be achieved using glutaraldehyde. In contrast to mannan oxidation, the glutaraldehyde approach allows to preserve mannoses with their native geometry, which may be functionally important for its receptor-mediated recognition. 相似文献
933.
934.
935.
Jolien Rijlaarsdam Irene Pappa Esther Walton Marian J. Bakermans-Kranenburg Viara R. Mileva-Seitz Ralph C.A. Rippe 《Epigenetics》2016,11(2):140-149
Prenatal maternal stress exposure has been associated with neonatal differential DNA methylation. However, the available evidence in humans is largely based on candidate gene methylation studies, where only a few CpG sites were evaluated. The aim of this study was to examine the association between prenatal exposure to maternal stress and offspring genome-wide cord blood methylation using different methods. First, we conducted a meta-analysis and follow-up pathway analyses. Second, we used novel region discovery methods [i.e., differentially methylated regions (DMRs) analyses]. To this end, we used data from two independent population-based studies, the Generation R Study (n = 912) and the Avon Longitudinal Study of Parents and Children (ALSPAC, n = 828), to (i) measure genome-wide DNA methylation in cord blood and (ii) extract a prenatal maternal stress composite. The meta-analysis (ntotal = 1,740) revealed no epigenome-wide (meta P <1.00e-07) associations of prenatal maternal stress exposure with neonatal differential DNA methylation. Follow-up analyses of the top hits derived from our epigenome-wide meta-analysis (meta P <1.00e-04) indicated an over-representation of the methyltransferase activity pathway. We identified no Bonferroni-corrected (P <1.00e-06) DMRs associated with prenatal maternal stress exposure. Combining data from two independent population-based samples in an epigenome-wide meta-analysis, the current study indicates that there are no large effects of prenatal maternal stress exposure on neonatal DNA methylation. Such replication efforts are essential in the search for robust associations, whether derived from candidate gene methylation or epigenome-wide studies. 相似文献
936.
Thermogenic respiratory processes drive the exponential increase of volatile organic compound emissions in Macrozamia cycad cones
下载免费PDF全文
![点击此处可从《Plant, cell & environment》网站下载免费的PDF全文](/ch/ext_images/free.gif)
L. Irene Terry Robert B. Roemer David T. Booth Chris J. Moore Gimme H. Walter 《Plant, cell & environment》2016,39(7):1588-1600
An important outcome of plant thermogenesis is increased emissions of volatiles that mediate pollinator behaviour. We investigated whether the large increase in emissions, mainly the monoterpene ß‐myrcene (>90%), during daily thermogenic events of Macrozamia macleayi and lucida cycad cones are due solely to the influence of high cone temperatures or are, instead, a result of increased respiratory rates during thermogenesis. We concurrently measured temperature, oxygen consumption and ß‐myrcene emission profiles during thermogenesis of pollen cones under typical environmental temperatures and during experimental manipulations of cone temperatures and aerobic conditions, all in the dark. The exponential rise in ß‐myrcene emissions never occurred without a prior, large increase in respiration, whereas an increase in cone temperature alone did not increase emissions. When respiration during thermogenesis was interrupted by anoxic conditions, ß‐myrcene emissions decreased. The increased emission rates are not a result of increased cone temperature per se (through increased enzyme activity or volatilization of stored volatiles) but are dependent on biosynthetic pathways associated with increased respiration during thermogenesis that provide the carbon, energy (ATP) and reducing compounds (NADPH) required for ß‐myrcene production through the methylerythritol phosphate (MEP) pathway. These findings establish the significant contribution of respiration to volatile production during thermogenesis. 相似文献
937.
Irene Zempi 《Ethnic and racial studies》2016,39(10):1738-1754
In the context of heightened suspicion and anti-Muslim stereotypes in a post-9/11 and 7/7 era, Muslim women who wear the niqab (face veil) are stigmatized, criminalized and marked as ‘dangerous’ to British/Western values. While the wearing of the niqab has elicited a good deal of media, political and public debates, little attention has been paid to the opinions of Muslim women who wear it. Drawing on individual and focus group interviews with Muslim women who wear the niqab in the UK, this article places at the centre of the debate the voices of those women who do wear it, and explores their reasons for adopting it. The findings show that the wearing of the niqab emerges as a personal choice, an expression of religious piety, public modesty and belonging to the ‘ummah’. It is also perceived as a form of agency, and non-conformity to Western consumerist culture and lifestyle. 相似文献
938.
939.
F1FO ATP Synthase Is Expressed at the Surface of Embryonic Rat Heart‐Derived H9c2 Cells and Is Affected by Cardiac‐Like Differentiation
下载免费PDF全文
![点击此处可从《Journal of cellular biochemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Marina Comelli Rossana Domenis Alessia Buso Irene Mavelli 《Journal of cellular biochemistry》2016,117(2):470-482
Taking advantage from the peculiar features of the embryonic rat heart‐derived myoblast cell line H9c2, the present study is the first to provide evidence for the expression of F1FO ATP synthase and of ATPase Inhibitory Factor 1 (IF1) on the surface of cells of cardiac origin, together documenting that they were affected through cardiac‐like differentiation. Subunits of both the catalytic F1 sector of the complex (ATP synthase‐β) and of the peripheral stalk, responsible for the correct F1‐FO assembly/coupling, (OSCP, b, F6) were detected by immunofluorescence, together with IF1. The expression of ATP synthase‐β, ATP synthase‐b and F6 were similar for parental and differentiated H9c2, while the levels of OSCP increased noticeably in differentiated cells, where the results of in situ Proximity Ligation Assay were consistent with OSCP interaction within ecto‐F1FO complexes. An opposite trend was shown by IF1 whose ectopic expression appeared greater in the parental H9c2. Here, evidence for the IF1 interaction with ecto‐F1FO complexes was provided. Functional analyses corroborate both sets of data. i) An F1FO ATP synthase contribution to the exATP production by differentiated cells suggests an augmented expression of holo‐F1FO ATP synthase on plasma membrane, in line with the increase of OSCP expression and interaction considered as a requirement for favoring the F1‐FO coupling. ii) The absence of exATP generation by the enzyme, and the finding that exATP hydrolysis was largely oligomycin‐insensitive, are in line in parental cells with the deficit of OSCP and suggest the occurrence of sub‐assemblies together evoking more regulation by IF1. J. Cell. Biochem. 9999: 1–13, 2015. © 2015 Wiley Periodicals, Inc. J. Cell. Biochem. 117: 470–482, 2016. © 2015 Wiley Periodicals, Inc. 相似文献
940.
Alexander D. Wright Michael Jarrett Irene Vavasour Elham Shahinfard Shannon Kolind Paul van Donkelaar Jack Taunton David Li Alexander Rauscher 《PloS one》2016,11(2)
Impact-related mild traumatic brain injuries (mTBI) are a major public health concern, and remain as one of the most poorly understood injuries in the field of neuroscience. Currently, the diagnosis and management of such injuries are based largely on patient-reported symptoms. An improved understanding of the underlying pathophysiology of mTBI is urgently needed in order to develop better diagnostic and management protocols. Specifically, dynamic post-injury changes to the myelin sheath in the human brain have not been examined, despite ‘compromised white matter integrity’ often being described as a consequence of mTBI. In this preliminary cohort study, myelin water imaging was used to prospectively evaluate changes in myelin water fraction, derived from the T2 decay signal, in two varsity hockey teams (45 players) over one season of athletic competition. 11 players sustained a concussion during competition, and were scanned at 72 hours, 2 weeks, and 2 months post-injury. Results demonstrated a reduction in myelin water fraction at 2 weeks post-injury in several brain areas relative to preseason scans, including the splenium of the corpus callosum, right posterior thalamic radiation, left superior corona radiata, left superior longitudinal fasciculus, and left posterior limb of the internal capsule. Myelin water fraction recovered to pre-season values by 2 months post-injury. These results may indicate transient myelin disruption following a single mTBI, with subsequent remyelination of affected neurons. Myelin disruption was not apparent in the athletes who did not experience a concussion, despite exposure to repetitive subconcussive trauma over a season of collegiate hockey. These findings may help to explain many of the metabolic and neurological deficits observed clinically following mTBI. 相似文献