全文获取类型
收费全文 | 535篇 |
免费 | 36篇 |
国内免费 | 1篇 |
出版年
2023年 | 6篇 |
2022年 | 11篇 |
2021年 | 34篇 |
2020年 | 21篇 |
2019年 | 13篇 |
2018年 | 28篇 |
2017年 | 21篇 |
2016年 | 23篇 |
2015年 | 24篇 |
2014年 | 38篇 |
2013年 | 51篇 |
2012年 | 47篇 |
2011年 | 37篇 |
2010年 | 28篇 |
2009年 | 24篇 |
2008年 | 27篇 |
2007年 | 20篇 |
2006年 | 21篇 |
2005年 | 9篇 |
2004年 | 14篇 |
2003年 | 15篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
排序方式: 共有572条查询结果,搜索用时 19 毫秒
91.
The relative availability of inorganic carbon and inorganic nitrogen influences the response of the dinoflagellate Protoceratium reticulatum to elevated CO2
下载免费PDF全文
![点击此处可从《Journal of phycology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
This work originates from three facts: (i) changes in CO2 availability influence metabolic processes in algal cells; (ii) Spatial and temporal variations of nitrogen availability cause repercussions on phytoplankton physiology; (iii) Growth and cell composition are dependent on the stoichiometry of nutritional resources. In this study, we assess whether the impact of rising pCO2 is influenced by N availability, through the impact that it would have on the C/N stoichiometry, in conditions of N sufficiency. Our experiments used the dinoflagellate Protoceratium reticulatum, which we cultured under three CO2 regimes (400, 1,000, and 5,000 ppmv, pH of 8.1) and either variable (the NO3? concentration was always 2.5 mmol · L?1) or constant (NO3? concentration varied to maintain the same Ci/NO3? ratio at all pCO2) Ci/NO3? ratio. Regardless of N availability, cells had higher specific growth rates, but lower cell dry weight and C and N quotas, at elevated CO2. The carbohydrate pool size and the C/N was unaltered in all treatments. The lipid content only decreased at high pCO2 at constant Ci/NO3? ratio. In the variable Ci/NO3? conditions, the relative abundance of Rubisco (and other proteins) also changed; this did not occur at constant Ci/NO3?. Thus, the biomass quality of P. reticulatum for grazers was affected by the Ci/NO3? ratio in the environment and not only by the pCO2, both with respect to the size of the main organic pools and the composition of the expressed proteome. 相似文献
92.
<正>Dear Editor,Porcine reproductive and respiratory syndrome virus(PRRSV),a member of the family Arteriviridae,represents one of the most challenging pathogens in the swine industry,with serious economic impact.Unfortunately,despite widespread application,vaccination has not been 相似文献
93.
Chiara Merigliano Romina Burla Mattia La Torre Simona Del Giudice Hsiangling Teo Chong Wai Liew Alexandre Chojnowski Wah Ing Goh Yolanda Olmos Klizia Maccaroni Maria Giubettini Irene Chiolo Jeremy G. Carlton Domenico Raimondo Fiammetta Vernì Colin L. Stewart Daniela Rhodes Graham D. Wright Brian E. Burke Isabella Saggio 《PLoS genetics》2021,17(8)
To complete mitosis, the bridge that links the two daughter cells needs to be cleaved. This step is carried out by the endosomal sorting complex required for transport (ESCRT) machinery. AKTIP, a protein discovered to be associated with telomeres and the nuclear membrane in interphase cells, shares sequence similarities with the ESCRT I component TSG101. Here we present evidence that during mitosis AKTIP is part of the ESCRT machinery at the midbody. AKTIP interacts with the ESCRT I subunit VPS28 and forms a circular supra-structure at the midbody, in close proximity with TSG101 and VPS28 and adjacent to the members of the ESCRT III module CHMP2A, CHMP4B and IST1. Mechanistically, the recruitment of AKTIP is dependent on MKLP1 and independent of CEP55. AKTIP and TSG101 are needed together for the recruitment of the ESCRT III subunit CHMP4B and in parallel for the recruitment of IST1. Alone, the reduction of AKTIP impinges on IST1 and causes multinucleation. Our data altogether reveal that AKTIP is a component of the ESCRT I module and functions in the recruitment of ESCRT III components required for abscission. 相似文献
94.
Quantifying patterns of fine root dynamics is crucial to the understanding of ecosystem structure and function, and in predicting
how ecosystems respond to disturbance. Part of this understanding involves consideration of the carbon lost through root turnover.
In the context of the rainfall pattern in the tropics, it was hypothesised that rainfall would strongly influence fine root
biomass and longevity. A field study was conducted to determine root biomass, elemental composition and the influence of rainfall
on longevity of fine roots in a tropical lowland evergreen rainforest at Danum Valley, Sabah, Malaysia. A combination of root
coring, elemental analysis and rhizotron observation methods were used. Fine (less than 2 mm diameter) root biomass was relatively
low (1700 kg ha −1) compared with previously described rainforest data. Standing root biomass was positively correlated with
preceding rainfall, and the low fine root biomass in the dry season contained higher concentrations of N and lower concentrations
of P and K than at other times. Observations on rhizotrons demonstrated that the decrease in fine root biomass in the dry
season was a product of both a decrease in fine root length appearance and an increase in fine root length disappearance.
Fitting an overall model to root survival time showed significant effects of rainfall preceding root disappearance, with the
hazard of root disappearance decreasing by 8 for each 1 mm increase in the average daily (30 day) rainfall preceding root
disappearance. While it is acknowledged that other factors have a part to play, this work demonstrates the importance of rainfall
and soil moisture in influencing root biomass and root disappearance in this tropical rainforest. 相似文献
95.
96.
97.
A computational procedure to identify significant overlap of differentially expressed and genomic imbalanced regions in cancer datasets
下载免费PDF全文
![点击此处可从《Nucleic acids research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
98.
Fabrizio de Mattia Caroline Gubser Michiel M.T. van Dommelen Henk-Jan Visch Felix Distelmaier Antonio Postigo Tomas Luyten Jan B. Parys Humbert de Smedt Geoffey L. Smith Peter H.G.M. Willems Frank J.M. van Kuppeveld 《Molecular biology of the cell》2009,20(16):3638-3645
Golgi antiapoptotic protein (GAAP) is a novel regulator of cell death that is highly conserved in eukaryotes and present in some poxviruses, but its molecular mechanism is unknown. Given that alterations in intracellular Ca2+ homeostasis play an important role in determining cell sensitivity to apoptosis, we investigated if GAAP affected Ca2+ signaling. Overexpression of human (h)-GAAP suppressed staurosporine-induced, capacitative Ca2+ influx from the extracellular space. In addition, it reduced histamine-induced Ca2+ release from intracellular stores through inositol trisphosphate receptors. h-GAAP not only decreased the magnitude of the histamine-induced Ca2+ fluxes from stores to cytosol and mitochondrial matrices, but it also reduced the induction and frequency of oscillatory changes in cytosolic Ca2+. Overexpression of h-GAAP lowered the Ca2+ content of the intracellular stores and decreased the efficacy of IP3, providing possible explanations for the observed results. Opposite effects were obtained when h-GAAP was knocked down by siRNA. Thus, our data demonstrate that h-GAAP modulates intracellular Ca2+ fluxes induced by both physiological and apoptotic stimuli. 相似文献
99.
Silvia Castelli Alessia Campagna Cinzia Tesauro Pietro Tagliatesta Mattia Falconi Hemanta K Majumder 《Archives of biochemistry and biophysics》2009,486(2):103-112
Conjugated eicosapentaenoic acid (cEPA) has been found to have antitumor effects which has been ascribed to their ability to inhibit DNA topoisomerases and DNA polymerases. We here show that cEPA inhibits the catalytic activity of human topoisomerase I, but unlike camptothecin it does not stabilize the cleavable complex, indicating a different mechanism of action. cEPA inhibits topoisomerase by impeding the catalytic cleavage of the DNA substrate as demonstrated using specific oligonucleotide substrates, and prevents the stabilization of the cleavable complex by camptothecin. Preincubation of the inhibitor with the enzyme is required to obtain complete inhibition. Molecular docking simulations indicate that the preferred cEPA binding site is proximal to the active site with the carboxylic group strongly interacting with the positively charged K443 and K587. Taken together the results indicate that cEPA inhibitor does not prevent DNA binding but inhibits DNA cleavage, binding in a region close to the topoisomerase active site. 相似文献
100.
Alessandra Abenavoli Mattia Lorenzo DiFrancesco Indra Schroeder Svetlana Epimashko Sabrina Gazzarrini Ulf Peter Hansen Gerhard Thiel Anna Moroni 《The Journal of general physiology》2009,134(3):219-229
Kcv from the chlorella virus PBCV-1 is a viral protein that forms a tetrameric, functional K+ channel in heterologous systems. Kcv can serve as a model system to study and manipulate basic properties of the K+ channel pore because its minimalistic structure (94 amino acids) produces basic features of ion channels, such as selectivity, gating, and sensitivity to blockers. We present a characterization of Kcv properties at the single-channel level. In symmetric 100 mM K+, single-channel conductance is 114 ± 11 pS. Two different voltage-dependent mechanisms are responsible for the gating of Kcv. “Fast” gating, analyzed by β distributions, is responsible for the negative slope conductance in the single-channel current–voltage curve at extreme potentials, like in MaxiK potassium channels, and can be explained by depletion-aggravated instability of the filter region. The presence of a “slow” gating is revealed by the very low (in the order of 1–4%) mean open probability that is voltage dependent and underlies the time-dependent component of the macroscopic current. 相似文献