全文获取类型
收费全文 | 3699篇 |
免费 | 356篇 |
专业分类
4055篇 |
出版年
2024年 | 10篇 |
2023年 | 40篇 |
2022年 | 90篇 |
2021年 | 170篇 |
2020年 | 65篇 |
2019年 | 109篇 |
2018年 | 117篇 |
2017年 | 96篇 |
2016年 | 188篇 |
2015年 | 251篇 |
2014年 | 242篇 |
2013年 | 263篇 |
2012年 | 370篇 |
2011年 | 308篇 |
2010年 | 180篇 |
2009年 | 159篇 |
2008年 | 214篇 |
2007年 | 208篇 |
2006年 | 177篇 |
2005年 | 162篇 |
2004年 | 171篇 |
2003年 | 116篇 |
2002年 | 135篇 |
2001年 | 14篇 |
2000年 | 19篇 |
1999年 | 16篇 |
1998年 | 28篇 |
1997年 | 16篇 |
1996年 | 14篇 |
1995年 | 8篇 |
1994年 | 16篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1974年 | 4篇 |
1970年 | 3篇 |
1967年 | 2篇 |
1902年 | 1篇 |
1900年 | 2篇 |
1899年 | 1篇 |
排序方式: 共有4055条查询结果,搜索用时 0 毫秒
41.
42.
Cerian Tatchley Heather Paton Emma Robertson Jeroen Minderman Nicholas Hanley Kirsty Park 《PloS one》2016,11(3)
Small Wind Turbines (SWTs) are a growing micro-generation industry with over 870,000 installed units worldwide. No research has focussed on public attitudes towards SWTs, despite evidence the perception of such attitudes are key to planning outcomes and can be a barrier to installations. Here we present the results of a UK wide mail survey investigating public attitudes towards SWTs. Just over half of our respondents, who were predominantly older, white males, felt that SWTs were acceptable across a range of settings, with those on road signs being most accepted and least accepted in hedgerows and gardens. Concern about climate change positively influenced how respondents felt about SWTs. Respondent comments highlight visual impacts and perceptions of the efficiency of this technology are particularly important to this sector of the UK public. Taking this into careful consideration, alongside avoiding locating SWTs in contentious settings such as hedgerows and gardens where possible, may help to minimise public opposition to proposed installations. 相似文献
43.
Hyperalgesia to mechanical and thermal stimuli are characteristics of a range of disorders such as tennis elbow, whiplash and fibromyalgia. This study evaluated the presence of local and widespread mechanical and thermal hyperalgesia in individuals with knee osteoarthritis, compared to healthy control subjects. Twenty-three subjects with knee osteoarthritis and 23 healthy controls, matched for age, gender and body mass index, were recruited for the study. Volunteers with any additional chronic pain conditions were excluded. Pain thresholds to pressure, cold and heat were tested at the knee, ipsilateral heel and ipsilateral elbow, in randomized order, using standardised methodology. Significant between-groups differences for pressure pain and cold pain thresholds were found with osteoarthritic subjects demonstrating significantly increased sensitivity to both pressure (p = .018) and cold (p = .003) stimuli, compared with controls. A similar pattern of results extended to the pain-free ipsilateral ankle and elbow indicating widespread pressure and cold hyperalgesia. No significant differences were found between groups for heat pain threshold, although correlations showed that subjects with greater sensitivity to pressure pain were also likely to be more sensitive to both cold pain and heat pain. This study found widespread elevated pain thresholds in subjects with painful knee osteoarthritis, suggesting that altered nociceptive system processing may play a role in ongoing arthritic pain for some patients. 相似文献
44.
Emma Tham Anna Lindstrand Avni Santani Helena Malmgren Addie Nesbitt Holly?A. Dubbs Elaine?H. Zackai Michael?J. Parker Francisca Millan Kenneth Rosenbaum Golder?N. Wilson Ann Nordgren 《American journal of human genetics》2015,96(3):507-513
Through a multi-center collaboration study, we here report six individuals from five unrelated families, with mutations in KAT6A/MOZ detected by whole-exome sequencing. All five different de novo heterozygous truncating mutations were located in the C-terminal transactivation domain of KAT6A: : c.3116_3117 delCT, p.(Ser1039∗); c.3830_3831insTT, p.(Arg1278Serfs∗17); c.3879 dupA, p.(Glu1294Argfs∗19); c.4108G>T p.(Glu1370∗) and c.4292 dupT, p.(Leu1431Phefs∗8). An additional subject with a 0.23 MB microdeletion including the entire KAT6A reading frame was identified with genome-wide array comparative genomic hybridization. Finally, by detailed clinical characterization we provide evidence that heterozygous mutations in KAT6A cause a distinct intellectual disability syndrome. The common phenotype includes hypotonia, intellectual disability, early feeding and oromotor difficulties, microcephaly and/or craniosynostosis, and cardiac defects in combination with subtle facial features such as bitemporal narrowing, broad nasal tip, thin upper lip, posteriorly rotated or low-set ears, and microretrognathia. The identification of human subjects complements previous work from mice and zebrafish where knockouts of Kat6a/kat6a lead to developmental defects. NM_001099412.1相似文献
45.
Bode A. Olukolu Guan-Feng Wang Vijay Vontimitta Bala P. Venkata Sandeep Marla Jiabing Ji Emma Gachomo Kevin Chu Adisu Negeri Jacqueline Benson Rebecca Nelson Peter Bradbury Dahlia Nielsen James B. Holland Peter J. Balint-Kurti Gurmukh Johal 《PLoS genetics》2014,10(8)
Much remains unknown of molecular events controlling the plant hypersensitive defense response (HR), a rapid localized cell death that limits pathogen spread and is mediated by resistance (R-) genes. Genetic control of the HR is hard to quantify due to its microscopic and rapid nature. Natural modifiers of the ectopic HR phenotype induced by an aberrant auto-active R-gene (Rp1-D21), were mapped in a population of 3,381 recombinant inbred lines from the maize nested association mapping population. Joint linkage analysis was conducted to identify 32 additive but no epistatic quantitative trait loci (QTL) using a linkage map based on more than 7000 single nucleotide polymorphisms (SNPs). Genome-wide association (GWA) analysis of 26.5 million SNPs was conducted after adjusting for background QTL. GWA identified associated SNPs that colocalized with 44 candidate genes. Thirty-six of these genes colocalized within 23 of the 32 QTL identified by joint linkage analysis. The candidate genes included genes predicted to be in involved programmed cell death, defense response, ubiquitination, redox homeostasis, autophagy, calcium signalling, lignin biosynthesis and cell wall modification. Twelve of the candidate genes showed significant differential expression between isogenic lines differing for the presence of Rp1-D21. Low but significant correlations between HR-related traits and several previously-measured disease resistance traits suggested that the genetic control of these traits was substantially, though not entirely, independent. This study provides the first system-wide analysis of natural variation that modulates the HR response in plants. 相似文献
46.
Stephanie G. Gardner Emma F. Camp David J. Smith Tim Kahlke Eslam O. Osman Gilberte Gendron Benjamin C. C. Hume Claudia Pogoreutz Christian R. Voolstra David J. Suggett 《Ecology and evolution》2019,9(3):938-956
Repeat marine heat wave‐induced mass coral bleaching has decimated reefs in Seychelles for 35 years, but how coral‐associated microbial diversity (microalgal endosymbionts of the family Symbiodiniaceae and bacterial communities) potentially underpins broad‐scale bleaching dynamics remains unknown. We assessed microbiome composition during the 2016 heat wave peak at two contrasting reef sites (clear vs. turbid) in Seychelles, for key coral species considered bleaching sensitive (Acropora muricata, Acropora gemmifera) or tolerant (Porites lutea, Coelastrea aspera). For all species and sites, we sampled bleached versus unbleached colonies to examine how microbiomes align with heat stress susceptibility. Over 30% of all corals bleached in 2016, half of which were from Acropora sp. and Pocillopora sp. mass bleaching that largely transitioned to mortality by 2017. Symbiodiniaceae ITS2‐sequencing revealed that the two Acropora sp. and P. lutea generally associated with C3z/C3 and C15 types, respectively, whereas C. aspera exhibited a plastic association with multiple D types and two C3z types. 16S rRNA gene sequencing revealed that bacterial communities were coral host‐specific, largely through differences in the most abundant families, Hahellaceae (comprising Endozoicomonas), Rhodospirillaceae, and Rhodobacteraceae. Both Acropora sp. exhibited lower bacterial diversity, species richness, and community evenness compared to more bleaching‐resistant P. lutea and C. aspera. Different bleaching susceptibility among coral species was thus consistent with distinct microbiome community profiles. These profiles were conserved across bleached and unbleached colonies of all coral species. As this pattern could also reflect a parallel response of the microbiome to environmental changes, the detailed functional associations will need to be determined in future studies. Further understanding such microbiome‐environmental interactions is likely critical to target more effective management within oceanically isolated reefs of Seychelles. 相似文献
47.
Biodegradable polyesters such as poly(epsilon-caprolactone) (PCL) have a number of biomedical applications; however, their usage is often limited by a lack of biological functionality. In this paper, a PCL-based polymer containing pendent groups activated by 4-nitrophenyl chloroformate (NPC) and reactive toward primary amines has been cast into thin films. The reactivity of the films toward poly(l-lysine) and the cell adhesion peptide, GRGDS, was assessed, and their cell adhesive capabilities were characterized. ATR-FTIR analysis found that NPC functional groups were present on the surface of the cast film, and the synthesis, conjugation, and visualization of a fluorescent molecule on these films further demonstrated the success of this functionalization methodology. The immersion of these films into a solution of either poly(l-lysine) (PLL) or GRGDS in PBS (pH 7.4) and subsequent 3T3 fibroblast adhesion studies demonstrated significant improvement in cell adhesion and spreading over films cast from unmodified PCL. This investigation has shown that this novel NPC-containing polymer can be utilized in many applications where increased cellular adhesion is required, or the coupling of specific molecules to polymer surfaces is of interest. 相似文献
48.
Bo Wang Daniele Ramazzotti Luca De Sano Junjie Zhu Emma Pierson Serafim Batzoglou 《Proteomics》2018,18(2)
SIMLR (S ingle‐cell I nterpretation via M ulti‐kernel L eaR ning), an open‐source tool that implements a novel framework to learn a sample‐to‐sample similarity measure from expression data observed for heterogenous samples, is presented here. SIMLR can be effectively used to perform tasks such as dimension reduction, clustering, and visualization of heterogeneous populations of samples. SIMLR was benchmarked against state‐of‐the‐art methods for these three tasks on several public datasets, showing it to be scalable and capable of greatly improving clustering performance, as well as providing valuable insights by making the data more interpretable via better a visualization. SIMLR is available on https://github.com/BatzoglouLabSU/SIMLR GitHub in both R and MATLAB implementations. Furthermore, it is also available as an R package on http://bioconductor.org 相似文献
49.
Inorganic carbon (Ci) uptake and efflux has been investigated in the marine microalga Nannochloropsis gaditana Lubian by monitoring CO2 fluxes in cell suspensions using mass spectrometry. Addition of H13CO3
− to cell suspensions in the dark caused a transient increase in the CO2 concentration in the medium far in excess of the equilibrium CO2 concentration. The magnitude of this release was dependent on the length of time the cells had been kept in the dark. Once
equilibrium between the Ci species had been achieved, a CO2 efflux was observed after saturating light intensity was applied to the cells. External carbonic anhydrase (CA) was not detected
nor does this species demonstrate a capacity to take up CO2 by active transport. Photosynthetic O2 evolution and the release CO2 in the dark depend on HCO3
− uptake since both were inhibited by the anion exchange inhibitor, 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (DIDS).
The bicarbonate uptake mechanism requires light but can also continue for short periods in the dark. Ethoxyzolamide, a CA
inhibitor, markedly inhibited CO2 efflux in the dark, indicating that CO2 efflux was dependent upon the intracellular dehydration of HCO3
−. These results indicate that Nannochloropsis possesses a bicarbonate uptake system which causes the accumulation of high intracellular Ci levels and an internal CA which
maintains the equilibrium between CO2 and HCO3
− and thus causes a subsequent release of CO2 to the external medium.
Received: 20 September 1999 / Accepted: 25 October 1999 相似文献
50.
Relationship between body mass,lean mass,fat mass,and limb bone cross‐sectional geometry: Implications for estimating body mass and physique from the skeleton 下载免费PDF全文