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991.
992.
PEX5 protein binds monomeric catalase blocking its tetramerization and releases it upon binding the N-terminal domain of PEX14 总被引:1,自引:0,他引:1
Freitas MO Francisco T Rodrigues TA Alencastre IS Pinto MP Grou CP Carvalho AF Fransen M Sá-Miranda C Azevedo JE 《The Journal of biological chemistry》2011,286(47):40509-40519
Newly synthesized peroxisomal matrix proteins are targeted to the organelle by PEX5. PEX5 has a dual role in this process. First, it acts as a soluble receptor recognizing these proteins in the cytosol. Subsequently, at the peroxisomal docking/translocation machinery, PEX5 promotes their translocation across the organelle membrane. Despite significant advances made in recent years, several aspects of this pathway remain unclear. Two important ones regard the formation and disruption of the PEX5-cargo protein interaction in the cytosol and at the docking/translocation machinery, respectively. Here, we provide data on the interaction of PEX5 with catalase, a homotetrameric enzyme in its native state. We found that PEX5 interacts with monomeric catalase yielding a stable protein complex; no such complex was detected with tetrameric catalase. Binding of PEX5 to monomeric catalase potently inhibits its tetramerization, a property that depends on domains present in both the N- and C-terminal halves of PEX5. Interestingly, the PEX5-catalase interaction is disrupted by the N-terminal domain of PEX14, a component of the docking/translocation machinery. One or two of the seven PEX14-binding diaromatic motifs present in the N-terminal half of PEX5 are probably involved in this phenomenon. These results suggest the following: 1) catalase domain(s) involved in the interaction with PEX5 are no longer accessible upon tetramerization of the enzyme; 2) the catalase-binding interface in PEX5 is not restricted to its C-terminal peroxisomal targeting sequence type 1-binding domain and also involves PEX5 N-terminal domain(s); and 3) PEX14 participates in the cargo protein release step. 相似文献
993.
Figueras MJ Collado L Levican A Perez J Solsona MJ Yustes C 《Systematic and applied microbiology》2011,34(2):105-109
Nineteen bacteria isolates recovered from shellfish samples (mussels and oysters) showed a new and specific 16S rDNA-RFLP pattern with an Arcobacter identification method designed to recognize all species described up to 2008. These results suggested that they could belong to a new species. ERIC-PCR revealed that the 19 isolates belonged to 3 different strains. The sequence of the 16S rRNA gene of a representative strain (F98-3T) showed 97.6% similarity with the closest species Arcobacter marinus followed by Arcobacter halophilus (95.6%) and Arcobacter mytili (94.7%). The phylogenetic analysis with the16S rRNA, rpoB, gyrB and hsp60 genes placed the shellfish strains within the same cluster as the three species mentioned (also isolated from saline habitats) but they formed an independent phylogenetic line. The DDH results between strain F98-3T and A. marinus (54.8% ± 1.05), confirmed that it represents a new species. Several biochemical tests differentiated the shellfish isolates from all other Arcobacter species. Although the new species was different from A. mytili, they shared not only the same habitat (mussels) but also the characteristic of being so far the only Arcobacter species that are simultaneously negative for urea and indoxyl acetate hydrolysis. All results supported the classification of the shellfish strains as a new species, for which the name Arcobacter molluscorum sp. nov. with the type strain F98-3T is proposed (=CECT 7696T = LMG 25693T). 相似文献
994.
Johnson JS Meliton V Kim WK Lee KB Wang JC Nguyen K Yoo D Jung ME Atti E Tetradis S Pereira RC Magyar C Nargizyan T Hahn TJ Farouz F Thies S Parhami F 《Journal of cellular biochemistry》2011,112(6):1673-1684
Stimulation of bone formation by osteoinductive materials is of great clinical importance in spinal fusion surgery, repair of bone fractures, and in the treatment of osteoporosis. We previously reported that specific naturally occurring oxysterols including 20(S)-hydroxycholesterol (20S) induce the osteogenic differentiation of pluripotent mesenchymal cells, while inhibiting their adipogenic differentiation. Here we report the characterization of two structural analogues of 20S, Oxy34 and Oxy49, which induce the osteogenic and inhibit the adipogenic differentiation of bone marrow stromal cells (MSC) through activation of Hedgehog (Hh) signaling. Treatment of M2-10B4 MSC with Oxy34 or Oxy49 induced the expression of osteogenic differentiation markers Runx2, Osterix (Osx), alkaline phosphatase (ALP), bone sialoprotein (BSP), and osteocalcin (OCN), as well as ALP enzymatic activity and robust mineralization. Treatment with oxysterols together with PPARγ activator, troglitazone (Tro), inhibited mRNA expression for adipogenic genes PPARγ, LPL, and aP2, and inhibited the formation of adipocytes. Efficacy of Oxy34 and Oxy49 in stimulating bone formation in vivo was assessed using the posterolateral intertransverse process rat spinal fusion model. Rats receiving collagen implants with Oxy 34 or Oxy49 showed comparable osteogenic efficacy to BMP2/collagen implants as measured by radiography, MicroCT, and manual inspection. Histological analysis showed trabecular and cortical bone formation by oxysterols and rhBMP2 within the fusion mass, with robust adipogenesis in BMP2-induced bone and significantly less adipocytes in oxysterol-induced bone. These data suggest that Oxy34 and Oxy49 are effective novel osteoinductive molecules and may be suitable candidates for further development and use in orthopedic indications requiring local bone formation. 相似文献
995.
Background:
Metabolic syndrome refers to a constellation of conditions that increases a person’s risk of diabetes and cardiovascular disease. We describe the prevalence of metabolic syndrome and its components in relation to sociodemographic factors in the Canadian adult population.Methods:
We used data from cycle 1 of the Canadian Health Measures Survey, a cross-sectional survey of a representative sample of the population. We included data for respondents aged 18 years and older for whom fasting blood samples were available; pregnant women were excluded. We calculated weighted estimates of the prevalence of metabolic syndrome and its components in relation to age, sex, education level and income.Results:
The estimated prevalence of metabolic syndrome was 19.1%. Age was the strongest predictor of the syndrome: 17.0% of participants 18–39 years old had metabolic syndrome, as compared with 39.0% of those 70–79 years. Abdominal obesity was the most common component of the syndrome (35.0%) and was more prevalent among women than among men (40.0% v. 29.1%; p = 0.013). Men were more likely than women to have an elevated fasting glucose level (18.9% v. 13.6%; p = 0.025) and hypertriglyceridemia (29.0% v. 20.0%; p = 0.012). The prevalence of metabolic syndrome was higher among people in households with lower education and income levels.Interpretation:
About one in five Canadian adults had metabolic syndrome. People at increased risk were those in households with lower education and income levels. The burden of abdominal obesity, low HDL (high-density lipoprotein) cholesterol and hypertriglyceridemia among young people was especially of concern, because the risk of cardiovascular disease increases with age.Chronic disease contributes significantly to morbidity and mortality in the Canadian population.1 As such, the economic costs are substantial. Metabolic syndrome refers to a constellation of conditions that approximately doubles a person’s risk of cardiovascular disease, independently of other risk factors.2–5 The cause of metabolic syndrome has not been fully elucidated; a summary of the current proposed mechanisms is discussed elsewhere.6Several sets of criteria have been established for the detection of metabolic syndrome, many of which have been continually updated.6–8 The set of criteria most commonly used in the past was published in the third report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III criteria).9 Recently, the International Diabetes Federation, the American Heart Association, the National Heart, Lung, and Blood Institute, and other organizations collaborated to release a unified set of criteria.10The Canadian Health Measures Survey, conducted in 2007–2009, was the first cross-sectional survey of a representative sample of Canadians that collected biological samples since the Canadian Heart Health Surveys about 20 years ago.11 We used data from the Canadian Health Measures Survey to describe the prevalence of metabolic syndrome and its components by age, sex, education level and income adequacy in a sample of the Canadian adult population. Because different studies have used various criteria in the past to define metabolic syndrome, and because there is continuing controversy as to the appropriate criteria, we calculated the prevalence according to several types of criteria to better facilitate comparison to findings from past and future studies. 相似文献996.
Esther Fernández-Miñano Clara Ortiz Ascensión Vicente José L. Calvo Antonio J. Ortiz 《Biometals》2011,24(5):935-941
Although the metal devices used in orthodontic treatments are manufactured highly resistance to corrosion, they may still
suffer some localized corrosion resulting from the oral cavity conditions. The corrosion causes the release of metals from
the alloys used for their manufacture. In this report, we evaluated the in vivo metal ions release of three alloys (stainless
steel, titanium and nickel-free) usually used in the orthodontics treatments and its genotoxicity. We applied to 15 patients,
between 12 and 16 years, 4 tubes and 20 brackets. Samples from oral mucosa were taken before the treatment and 30 days later.
The concentration of the titanium, chromium, manganese, cobalt, nickel, molybdenum and iron were detected using inductively
coupled plasma mass spectrometry (ICP-MS). The genotoxicity was measured with a comet assay (Olive moment). The oral mucosa
cells in contact with the stainless steel alloy displayed the greatest titanium and manganese concentrations and those in
contact with the nickel-free alloy presented the greatest concentration of chromium and iron. Both alloys, stainless steel
and nickel-free, induced a higher DNA damage in the oral mucosa cells than the titanium alloy, in which the Olive moment was
similar to controls. Based on the results of our study, we can conclude that titanium brackets and tubes are the most biocompatible
of the three alloys. 相似文献
997.
Raquel O. Vasconcelos Paulo J. Fonseca M. Clara P. Amorim Friedrich Ladich 《Proceedings. Biological sciences / The Royal Society》2011,278(1707):826-834
Many fishes rely on their auditory skills to interpret crucial information about predators and prey, and to communicate intraspecifically. Few studies, however, have examined how complex natural sounds are perceived in fishes. We investigated the representation of conspecific mating and agonistic calls in the auditory system of the Lusitanian toadfish Halobatrachus didactylus, and analysed auditory responses to heterospecific signals from ecologically relevant species: a sympatric vocal fish (meagre Argyrosomus regius) and a potential predator (dolphin Tursiops truncatus). Using auditory evoked potential (AEP) recordings, we showed that both sexes can resolve fine features of conspecific calls. The toadfish auditory system was most sensitive to frequencies well represented in the conspecific vocalizations (namely the mating boatwhistle), and revealed a fine representation of duration and pulsed structure of agonistic and mating calls. Stimuli and corresponding AEP amplitudes were highly correlated, indicating an accurate encoding of amplitude modulation. Moreover, Lusitanian toadfish were able to detect T. truncatus foraging sounds and A. regius calls, although at higher amplitudes. We provide strong evidence that the auditory system of a vocal fish, lacking accessory hearing structures, is capable of resolving fine features of complex vocalizations that are probably important for intraspecific communication and other relevant stimuli from the auditory scene. 相似文献
998.
999.
Background and Aims
Due in part to biophysical sized-related constraints, insects unlike vertebrates are seldom expected to act as primary seed dispersers via ingestion of fruits and seeds (endozoochory). The Mediterranean parasitic plant Cytinus hypocistis, however, possesses some characteristics that may facilitate endozoochory by beetles. By combining a long-term field study with experimental manipulation, we tested whether C. hypocistis seeds are endozoochorously dispersed by beetles.Methods
Field studies were carried out over 4 years on six populations in southern Spain. We recorded the rate of natural fruit consumption by beetles, the extent of beetle movement, beetle behaviour and the relative importance of C. hypocistis fruits in beetle diet.Key Results
The tenebrionid beetle Pimelia costata was an important disperser of C. hypocistis seeds, consuming up to 17·5 % of fruits per population. Forty-six per cent of beetles captured in the field consumed C. hypocistis fruits, with up to 31 seeds found in individual beetle frass. An assessment of seeds following passage through the gut of beetles indicated that seeds remained intact and viable and that the proportion of viable seeds from beetle frass was not significantly different from that of seeds collected directly from fruits.Conclusions
A novel plant–animal interaction is revealed; endozoochory by beetles may facilitate the dispersal of viable seeds after passage through the gut away from the parent plant to potentially favourable underground sites offering a high probability of germination and establishment success. Such an ecological role has until now been attributed only to vertebrates. Future studies should consider more widely the putative role of fruit and seed ingestion by invertebrates as a dispersal mechanism, particularly for those plant species that possess small seeds. 相似文献1000.
Francesconi G Francesconi do Valle AC Passos SL de Lima Barros MB de Almeida Paes R Curi AL Liporage J Porto CF Galhardo MC 《Mycopathologia》2011,171(5):349-354