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991.
Bernard Prévosto Anne Bousquet-Mélou Christian Ripert Catherine Fernandez 《Plant Ecology》2011,212(4):627-638
Biodiversity maintenance is a key component of Mediterranean forest management, yet studies on the effects of silvicultural
treatments on plant diversity are scarce. Our experiment assessed the impact of five different site preparation treatments
on the composition, diversity, ecological traits (life-form, pollination mode, leaf morphology, seed dispersal mode), indicator
values (shade tolerance, nutrients demand) of the understory vegetation in a mature thinned Pinus halepensis stand in southern France. The treatments—chopping, chopping followed by scarification in one or two directions, prescribed
burning, control—were replicated four times and applied on a total of 40 plots. Vegetation relevés were performed on each
plot in the first, second and fourth year following treatment applications. Plant diversity, measured by the species richness
or Shannon’s index, increased in the non-control treatment plots in the first year but then decreased through time. Vegetation
composition differed between treatments, with the chopping treatment exhibiting composition and ecological trait values more
comparable to those of control plots than the other treatments. The burning and scarification treatments led to higher abundance
of therophytes, plants with malacophyllous leaves and insect-pollinated plants, and shade-intolerant and nutrient-demanding
species. However, these changes were transient in time, the shade-intolerant species remained abundant but the ruderal species
decreased while the ligneous species increased indicating a gradual return to a forest vegetation composition. For the Mediterranean
area, most of the findings were similar to those in temperate forests subjected to the same site preparation treatments. 相似文献
992.
Michelle Keightley Stephanie Green Nick Reed Sabrina Agnihotri Amy Wilkinson Nancy Lobaugh 《Journal of visualized experiments : JoVE》2011,(47)
One of the most commonly reported injuries in children who participate in sports is concussion or mild traumatic brain injury (mTBI)1. Children and youth involved in organized sports such as competitive hockey are nearly six times more likely to suffer a severe concussion compared to children involved in other leisure physical activities2. While the most common cognitive sequelae of mTBI appear similar for children and adults, the recovery profile and breadth of consequences in children remains largely unknown2, as does the influence of pre-injury characteristics (e.g. gender) and injury details (e.g. magnitude and direction of impact) on long-term outcomes. Competitive sports, such as hockey, allow the rare opportunity to utilize a pre-post design to obtain pre-injury data before concussion occurs on youth characteristics and functioning and to relate this to outcome following injury. Our primary goals are to refine pediatric concussion diagnosis and management based on research evidence that is specific to children and youth. To do this we use new, multi-modal and integrative approaches that will:1.Evaluate the immediate effects of head trauma in youth
2.Monitor the resolution of post-concussion symptoms (PCS) and cognitive performance during recovery
3.Utilize new methods to verify brain injury and recoveryTo achieve our goals, we have implemented the Head Impact Telemetry (HIT) System. (Simbex; Lebanon, NH, USA). This system equips commercially available Easton S9 hockey helmets (Easton-Bell Sports; Van Nuys, CA, USA) with single-axis accelerometers designed to measure real-time head accelerations during contact sport participation 3 - 5. By using telemetric technology, the magnitude of acceleration and location of all head impacts during sport participation can be objectively detected and recorded. We also use functional magnetic resonance imaging (fMRI) to localize and assess changes in neural activity specifically in the medial temporal and frontal lobes during the performance of cognitive tasks, since those are the cerebral regions most sensitive to concussive head injury 6. Finally, we are acquiring structural imaging data sensitive to damage in brain white matter.Download video file.(44M, mov) 相似文献
993.
994.
Sharma K Åkerström S Sharma AK Chow VT Teow S Abrenica B Booth SA Booth TF Mirazimi A Lal SK 《PloS one》2011,6(5):e19436
BACKGROUND: 9b is an accessory protein of the SARS-CoV. It is a small protein of 98 amino acids and its structure has been solved recently. 9b is known to localize in the extra-nuclear region and has been postulated to possess a nuclear export signal (NES), however the role of NES in 9b functioning is not well understood. PRINCIPAL FINDINGS/METHODOLOGY: In this report, we demonstrate that 9b in the absence of any nuclear localization signal (NLS) enters the nucleus by passive transport. Using various cell cycle inhibitors, we have shown that the nuclear entry of 9b is independent of the cell cycle. Further, we found that 9b interacts with the cellular protein Crm1 and gets exported out of the nucleus using an active NES. We have also revealed that this NES activity influences the half-life of 9b and affects host cell death. We found that an export signal deficient SARS-CoV 9b protein induces apoptosis in transiently transfected cells and showed elevated caspase-3 activity. CONCLUSION/SIGNIFICANCE: Here, we showed that nuclear shuttling of 9b and its interaction with Crm1 are essential for the proper degradation of 9b and blocking the nuclear export of this protein induces apoptosis. This phenomenon may be critical in providing a novel role to the 9b accessory protein of SARS-CoV. 相似文献
995.
RING finger protein 13 (RNF13) is a ubiquitously expressed, highly regulated ubiquitin ligase anchored in endosome membranes. A RING domain located in the cytoplasmic half of this type 1 membrane protein mediates ubiquitination in vitro but physiological substrates have not yet been identified. The protein localized in endosomal membranes undergoes extensive proteolysis in a proteasome-dependent manner, but the mRNA level can be increased and the encoded protein stabilized under specific physiological conditions. The cytoplasmic half of RNF13 is released from the membrane by regulatory proteases and therefore has the potential to mediate ubiquitination at distant sites independent of the full-length protein. In response to protein kinase C activation, the full-length protein is stabilized and moves to recycling endosomes and to the inner nuclear membrane, which exposes the RING domain to the nucleoplasm. Thus RNF13 is a ubiquitin ligase that can potentially mediate ubiquitination in endosomes, on the plasma membrane, in the cytoplasm, in the nucleoplasm or on the inner nuclear membrane, with the site(s) regulated by signaling events that modulate protein targeting and proteolysis. 相似文献
996.
997.
998.
Madec Y Germanaud D Moya-Alvarez V Alkassoum W Issa A Amadou M Tchiombiano S Pizzocolo C Huber F Diallo S Abdoulaye-Mamadou R 《PloS one》2011,6(7):e22787
Background
In developing countries, malnutrition is a contributing factor in over 50% of child deaths. Mortality rates are higher in underweight children, and HIV-infection is known to increase underweight. Our goals were to evaluate the prevalence of HIV among children hospitalised for severe malnutrition (SM) at the Niamey national hospital (Niger), and to compare renutrition and mortality by HIV-status.Methods
Retrospective study based on all children <5 years hospitalised for SM between January 1st 2008 and July 1st 2009. HIV-prevalence was the ratio of HIV+ children on the number of children tested. Duration of renutrition and mortality were described using survival curves.Results
During the study period, 477 children were hospitalised for SM. HIV testing was accepted in 470 (98.5%), of which 40 were HIV+ (HIV prevalence (95% confidence interval) of 8.6% (6.2–11.5)). Duration of renutrition was longer in HIV+ than HIV− children (mean: 22 vs. 15 days; p = 0.003). During renutrition, 8 (20%) and 61 (14%) HIV+ and HIV− children died, respectively (p = 0.81).Conclusion
Around 9% of children hospitalised for severe malnutrition were HIV infected, while in Niger HIV prevalence in adults is estimated at 0.8%. This pleads for wider access to HIV testing in this population. 相似文献999.
Pawlowski DR Metzger DJ Raslawsky A Howlett A Siebert G Karalus RJ Garrett S Whitehouse CA 《PloS one》2011,6(3):e17585
Yersinia pestis, the causative agent of plague, has caused several pandemics throughout history and remains endemic in the rodent populations of the western United States. More recently, Y. pestis is one of several bacterial pathogens considered to be a potential agent of bioterrorism. Thus, elucidating potential mechanisms of survival and persistence in the environment would be important in the event of an intentional release of the organism. One such mechanism is entry into the viable but non-culturable (VBNC) state, as has been demonstrated for several other bacterial pathogens. In this study, we showed that Y. pestis became nonculturable by normal laboratory methods after 21 days in a low-temperature tap water microcosm. We further show evidence that, after the loss of culturability, the cells remained viable by using a variety of criteria, including cellular membrane integrity, uptake and incorporation of radiolabeled amino acids, and protection of genomic DNA from DNase I digestion. Additionally, we identified morphological and ultrastructural characteristics of Y. pestis VBNC cells, such as cell rounding and large periplasmic spaces, by electron microscopy, which are consistent with entry into the VBNC state in other bacteria. Finally, we demonstrated resuscitation of a small number of the non-culturable cells. This study provides compelling evidence that Y. pestis persists in a low-temperature tap water microcosm in a viable state yet is unable to be cultured under normal laboratory conditions, which may prove useful in risk assessment and remediation efforts, particularly in the event of an intentional release of this organism. 相似文献
1000.
Gaudin F Nasreddine S Donnadieu AC Emilie D Combadière C Prévot S Machelon V Balabanian K 《PloS one》2011,6(7):e21546