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排序方式: 共有223条查询结果,搜索用时 15 毫秒
11.
Terryn N Heijnen L De Keyser A Van Asseldonck M De Clercq R Verbakel H Gielen J Zabeau M Villarroel R Jesse T Neyt P Hogers R Van Den Daele H Ardiles W Schueller C Mayer K Déhais P Rombauts S Van Montagu M Rouzé P Vos P 《FEBS letters》1999,445(2-3):237-245
As part of the European Scientists Sequencing Arabidopsis program, a contiguous region (396607 bp) located on chromosome 4 around the APETALA2 gene was sequenced. Analysis of the sequence and comparison to public databases predicts 103 genes in this area, which represents a gene density of one gene per 3.85 kb. Almost half of the genes show no significant homology to known database entries. In addition, the first 45 kb of the contig, which covers 11 genes, is similar to a region on chromosome 2, as far as coding sequences are concerned. This observation indicates that ancient duplications of large pieces of DNA have occurred in Arabidopsis. 相似文献
12.
An overview of the development of anti-tumor organotin derivatives, sometimes as active in vitro as doxorubicin, is presented and discussed. Solubility in water is an important issue, dominating the in vivo testing of compounds with promising in vitro properties. Several water-soluble organotin compounds gave the best in vitro activities. Novel, useful organotin anti-tumor compounds should be designed toward improved water solubility. 相似文献
13.
Christoph Börgers Martin Krupa Stan Gielen 《Journal of computational neuroscience》2010,28(3):509-526
A population of uncoupled neurons can often be brought close to synchrony by a single strong inhibitory input pulse affecting
all neurons equally. This mechanism is thought to underlie some brain rhythms, in particular gamma frequency (30–80 Hz) oscillations
in the hippocampus and neocortex. Here we show that synchronization by an inhibitory input pulse often fails for populations
of classical Hodgkin–Huxley neurons. Our reasoning suggests that in general, synchronization by inhibitory input pulses can
fail when the transition of the target neurons from rest to spiking involves a Hopf bifurcation, especially when inhibition
is shunting, not hyperpolarizing. Surprisingly, synchronization is more likely to fail when the inhibitory pulse is stronger
or longer-lasting. These findings have potential implications for the question which neurons participate in brain rhythms,
in particular in gamma oscillations. 相似文献
14.
Susy M Braun Jolanda C van Haastregt Anna J Beurskens Alexandra I Gielen Derick T Wade Jos M Schols 《BMC neurology》2010,10(1):74
Background
Within a multi-centre randomised controlled trial in three nursing homes, a process evaluation of a mental practice intervention was conducted. The main aims were to determine if the intervention was performed according to the framework and to describe the therapists' and participants' experiences with and opinions on the intervention. 相似文献15.
16.
Valère J. Goossens Steve A. de Jager Gert E. Grauls Marij Gielen Robert F. Vlietinck Catherine A. Derom Ruth J.F. Loos Sander S. Rensen Wim A. Buurman Jan W. Greve Marleen A. van Baak Petra F. Wolffs Cathrien A. Bruggeman Christian J.P.A. Hoebe 《Obesity (Silver Spring, Md.)》2011,19(1):220-221
Adenovirus infection has been shown to increase adiposity in chickens, mice, and nonhuman primates. Adenovirus type 36 (Ad‐36) DNA was detected in adipose tissues in these animal trials. In the United States, Ad‐36 significantly correlates with obesity as illustrated by an Ad‐36 seroprevalence of 30% in obese individuals and 11% in nonobese individuals. We investigated the possibility of a similar correlation of Ad‐36 in Dutch and Belgian persons. In total, 509 serum samples were analyzed for Ad‐36 antibodies using a serum neutralization assay. In addition, PCR was used to detect adenoviral DNA in visceral adipose tissue of 31 severely obese surgical patients. Our results indicated an overall Ad‐36 seroprevalence of 5.5% increasing with age. BMI of Ad‐36 seropositive humans was not significantly different from seronegative humans. No adenoviral DNA could be found using PCR on visceral adipose tissue. In conclusion, this first Ad‐36 study in the Netherlands and in Belgium indicates that Ad‐36 does not play a role as a direct cause of BMI increase and obesity in humans in Western Europe. 相似文献
17.
In the past decades, many studies have focussed on the relation between the input and output of neurons with the aim to understand
information processing by neurons. A particular aspect of neuronal information, which has not received much attention so far,
concerns the problem of information transfer when a neuron or a population of neurons receives input from two or more (populations
of) neurons, in particular when these (populations of) neurons carry different types of information. The aim of the present
study is to investigate the responses of neurons to multiple inputs modulated in the gamma frequency range. By a combination
of theoretical approaches and computer simulations, we test the hypothesis that enhanced modulation of synchronized excitatory
neuronal activity in the gamma frequency range provides an advantage over a less synchronized input for various types of neurons.
The results of this study show that the spike output of various types of neurons [i.e. the leaky integrate and fire neuron,
the quadratic integrate and fire neuron and the Hodgkin–Huxley (HH) neuron] and that of excitatory–inhibitory coupled pairs
of neurons, like the Pyramidal Interneuronal Network Gamma (PING) model, is highly phase-locked to the larger of two gamma-modulated
input signals. This implies that the neuron selectively responds to the input with the larger gamma modulation if the amplitude
of the gamma modulation exceeds that of the other signals by a certain amount. In that case, the output of the neuron is entrained
by one of multiple inputs and that other inputs are not represented in the output. This mechanism for selective information
transmission is enhanced for short membrane time constants of the neuron. 相似文献
18.
Cadmium stress: an oxidative challenge 总被引:5,自引:0,他引:5
Ann Cuypers Michelle Plusquin Tony Remans Marijke Jozefczak Els Keunen Heidi Gielen Kelly Opdenakker Ambily Ravindran Nair Elke Munters Tom J. Artois Tim Nawrot Jaco Vangronsveld Karen Smeets 《Biometals》2010,23(5):927-940
At the cellular level, cadmium (Cd) induces both damaging and repair processes in which the cellular redox status plays a crucial role. Being not redox-active, Cd is unable to generate reactive oxygen species (ROS) directly, but Cd-induced oxidative stress is a common phenomenon observed in multiple studies. The current review gives an overview on Cd-induced ROS production and anti-oxidative defense in organisms under different Cd regimes. Moreover, the Cd-induced oxidative challenge is discussed with a focus on damage and signaling as downstream responses. Gathering these data, it was clear that oxidative stress related responses are affected during Cd stress, but the apparent discrepancies observed in between the different studies points towards the necessity to increase our knowledge on the spatial and temporal ROS signature under Cd stress. This information is essential in order to reveal the exact role of Cd-induced oxidative stress in the modulation of downstream responses under a diverse array of conditions. 相似文献
19.
dsRNA-mediated resistance to Beet Necrotic Yellow Vein Virus infections in sugar beet (Beta vulgaris L. ssp. vulgaris) 总被引:1,自引:0,他引:1
Britt-Louise Lennefors Eugene I. Savenkov Jan Bensefelt Elisabeth Wremerth-Weich Petra van Roggen Stig Tuvesson Jari P. T. Valkonen Jan Gielen 《Molecular breeding : new strategies in plant improvement》2006,18(4):313-325
Rhizomania, one of the most devastating diseases in sugar beet, is caused by Beet Necrotic Yellow Vein Virus (BNYVV) belonging to the genus Benyvirus. Use of sugar beet varieties with resistance to BNYVV is generally considered as the only way to maintain a profitable yield on rhizomania-infested fields. As an alternative to natural resistance, we explored the transgenic expression of viral dsRNA for engineering resistance to rhizomania. Transgenic plants expressing an inverted repeat of a 0.4 kb fragment derived from the BNYVV replicase gene displayed high levels of resistance against different genetic strains of BNYVV when inoculated using the natural vector, Polymyxa betae. The resistance was maintained under high infection pressures and over prolonged growing periods in the greenhouse as well as in the field. Resistant plants accumulated extremely low amounts of transgene mRNA and high amounts of the corresponding siRNA in the roots, illustrative of RNA silencing as the underlying mechanism. The transgenic resistance compared very favourably to natural sources of resistance to rhizomania and thus offers an attractive alternative for breeding resistant sugar beet varieties. 相似文献
20.
Remans T Thijs S Truyens S Weyens N Schellingen K Keunen E Gielen H Cuypers A Vangronsveld J 《Annals of botany》2012,110(2):239-252