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21.
After TCR cross-linking, naive CD4(+)CD45RA(+) T cells switch to the expression of the CD45RO isoform and acquire effector functions. In this study we have shown that cAMP-elevating agents added to anti-CD3- and anti-CD28-stimulated cultures of T lymphocytes prevent acquisition of the CD45RO(+) phenotype and lead to the generation of a new subpopulation of primed CD4(+)CD45RA(+) effector cells (cAMP-primed CD45RA). These cells displayed a low apoptotic index, as the presence of dibutyryl cAMP (dbcAMP)-rescued cells from CD3/CD28 induced apoptosis. Inhibition of CD45 splicing by dbcAMP was not reverted by addition of exogenous IL-2. cAMP-primed CD45RA cells had a phenotype characteristic of memory/effector T lymphocytes, as they showed an up-regulated expression of CD2, CD44, and CD11a molecules, while the levels of CD62L Ag were down-regulated. These cells also expressed the activation markers CD30, CD71, and HLA class II Ags at an even higher level than CD3/CD28-stimulated cells in the absence of dbcAMP. In agreement with this finding, cAMP-primed CD45RA cells were very efficient in triggering allogenic responses in a MLR. In addition, cAMP-primed CD45RA cells produce considerable amounts of the Th2 cytokines, IL-4, IL-10, and IL-13, whereas the production of IFN-gamma and TNF-alpha was nearly undetectable. The elevated production of IL-13 by neonatal and adult cAMP-primed CD45RA cells was specially noticeable. The cAMP-dependent inhibition of CD45 splicing was not caused by the production of immunosuppressor cytokines. These results suggest that within the pool of CD4(+)CD45RA(+) cells there is a subpopulation of effector lymphocytes generated by activation in the presence of cAMP-elevating agents. 相似文献
22.
José Antonio López-Sáez Lourdes López-Merino Francisca Alba-Sánchez Sebastián Pérez-Díaz Daniel Abel-Schaad José S. Carrión 《Plant Ecology》2010,206(2):195-209
This article describes the patterns and processes of vegetation change and fire history in the Late Holocene (c. 2400 calendar year
BP) palaeoecological sequence of Lanzahíta, Sierra de Gredos in central Spain, and provides the first Iberian pollen sequence
undertaken within a monospecific Pinus pinaster woodland. These new data reassess not only the autochthonous nature of this pine species in the region and the Iberian Peninsula,
but also the naturalness of well-developed cluster pine forests. Conflicts of palaeoecological evidence with phytosociological
models of vegetation dynamics in the study region, and the relationships of P. pinaster with fire occurrence in Mediterranean-type ecosystems, are discussed. 相似文献
23.
Lourdes Hernandez-Apaolaza 《Planta》2014,240(3):447-458
Silicon protects plants against various biotic and abiotic stresses, including metal toxicity. Under a high metal concentration, Si can externally decrease metal availability to the plant by its precipitation in the growth media, and Si also affects the metal distribution inside the plant, diminishing the damage. Could Si also protect plants against metal deficiency stress? Recently, the physiological role of Si in relation to micronutrients deficiency symptoms has been assessed in several plant species in hydroponics. In cucumber, Si supply mitigated the symptoms of Fe deficiency, but this effect was not clear under Zn- or Mn-deficiency conditions. The main factor controlling this beneficial effect seems to be the Si contribution to the formation of metal deposits in the root and/or leaves apoplast and its role in their following remobilization when required. The enhancement of the content of long-distance transport molecules (such as citrate) due to Si addition should also contribute to the metal transport from root to shoot, which will diminish deficiency symptoms. 相似文献
24.
Tracking down human contamination in ancient human teeth 总被引:1,自引:0,他引:1
Sampietro ML Gilbert MT Lao O Caramelli D Lari M Bertranpetit J Lalueza-Fox C 《Molecular biology and evolution》2006,23(9):1801-1807
DNA contamination arising from the manipulation of ancient calcified tissue samples is a poorly understood, yet fundamental, problem that affects the reliability of ancient DNA (aDNA) studies. We have typed the mitochondrial DNA hypervariable region I of the only 6 people involved in the excavation, washing, and subsequent anthropological and genetic study of 23 Neolithic remains excavated from Granollers (Barcelona, Spain) and searched for their presence among the 572 clones generated during the aDNA analyses of teeth from these samples. Of the cloned sequences, 17.13% could be unambiguously identified as contaminants, with those derived from the people involved in the retrieval and washing of the remains present in higher frequencies than those of the anthropologist and genetic researchers. This finding confirms, for the first time, previous hypotheses that teeth samples are most susceptible to contamination at their initial excavation. More worrying, the cloned contaminant sequences exhibit substitutions that can be attributed to DNA damage after the contamination event, and we demonstrate that the level of such damage increases with time: contaminants that are >10 years old have approximately 5 times more damage than those that are recent. Furthermore, we demonstrate that in this data set, the damage rate of the old contaminant sequences is indistinguishable from that of the endogenous DNA sequences. As such, the commonly used argument that miscoding lesions observed among cloned aDNA sequences can be used to support data authenticity is misleading in scenarios where the presence of old contaminant sequences is possible. We argue therefore that the typing of those involved in the manipulation of the ancient human specimens is critical in order to ensure that generated results are accurate. 相似文献
25.
Facchini FD Vici AC Benassi VM Freitas LA Reis RA Jorge JA Terenzi HF Polizeli Mde L 《Bioprocess and biosystems engineering》2011,34(8):1027-1038
Fibrolytic enzyme production by Aspergillus japonicus C03 was optimized in a medium containing agro-industrial wastes, supplemented with peptone and yeast extract. A 23 full factorial composite and response surface methodology were used to design the experiments and analysis of results. Tropical
forages were hydrolyzed by A. japonicus C03 enzymatic extract in different levels, and they were also tested as enzymatic substrate. Optimal production to xylanase
was obtained with soybean bran added to crushed corncob (1:3), 0.01% peptone, and 0.2% yeast extract, initial pH 5.0, at 30 °C
under static conditions for 5 days of incubation. Optimal endoglucanase production was obtained with wheat bran added to sugarcane
bagasse (3:1), 0.01% peptone, and 0.2% yeast extract, initial pH 4.0, at 30 °C, for 6 days, under static conditions. Addition
of nitrogen sources as ammonium salts either inhibited or did not influence xylanase production. This enzymatic extract had
a good result on tropical forage hydrolyzes and showed better performance in the Brachiaria genera, due to their low cell wall lignin quantity. These results represent a step forward toward the use of low-cost agricultural
residues for the production of valuable enzymes with potential application in animal feed, using fermentation conditions. 相似文献
26.
Madhavan L. Raghavan Mauro M. Hanaoka Jarin A. Kratzberg Maria de Lourdes Higuchi Erasmo Simao da Silva 《Journal of biomechanics》2011,44(13):2501-2507
PurposeTo test the hypothesis that ruptured abdominal aortic aneurysms (AAA) are globally weaker than unruptured ones.MethodsFour ruptured and seven unruptured AAA specimens were harvested whole from fresh cadavers during autopsies performed over an 18-month period. Multiple regionally distributed longitudinally oriented rectangular strips were cut from each AAA specimen for a total of 77 specimen strips. Strips were subjected to uniaxial extension until failure. Sections from approximately the strongest and weakest specimen strips were studied histologically and histochemically. From the load-extension data, failure tension, failure stress and failure strain were calculated. Rupture site characteristics such as location, arc length of rupture and orientation of rupture were also documented.ResultsThe failure tension, a measure of the tissue mechanical caliber was remarkably similar between ruptured and unruptured AAA (group mean±standard deviation of within-subject means: 11.2±2.3 versus 11.6±3.6 N/cm; p=0.866 by mixed model ANOVA). In post-hoc analysis, there was little difference between the groups in other measures of tissue mechanical caliber as well such as failure stress (95±28 versus 98±23 N/cm2; p=0.870), failure strain (0.39±0.09 versus 0.36±0.09; p=0.705), wall thickness (1.7±0.4 versus 1.5±0.4 mm; p=0.470) , and % coverage of collagen within tissue cross section (49.6±12.9% versus 60.8±9.6%; p=0.133). In the four ruptured AAA, primary rupture sites were on the lateral quadrants (two on left; one on left-posterior; one on right). Remarkably, all rupture lines had a longitudinal orientation and ranged from 1 to 6 cm in length.ConclusionThe findings are not consistent with the hypothesis that ruptured aortic aneurysms are globally weaker than unruptured ones. 相似文献
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29.
Raimundo Fernandes de Araújo Júnior Tatiana Oliveira Souza Caroline Addison Xavier de Medeiros Lélia Batista de Souza Maria de Lourdes Freitas Hévio Freitas de Lucena Maria do Socorro Costa Feitosa Alves Aurigena Antunes de Araújo 《PloS one》2013,8(7)
Periodontal diseases are initiated primarily by Gram-negative, tooth-associated microbial biofilms that elicit a host response that causes osseous and soft tissue destruction. Carvedilol is a β-blocker used as a multifunctional neurohormonal antagonist that has been shown to act not only as an anti-oxidant but also as an anti-inflammatory drug. This study evaluated whether Carvedilol exerted a protective role against ligature-induced periodontitis in a rat model and defined how Carvedilol affected metalloproteinases and RANKL/RANK/OPG expression in the context of bone remodeling. Rats were randomly divided into 5 groups (n = 10/group): (1) non-ligated (NL), (2) ligature-only (LO), and (3) ligature plus Carvedilol (1, 5 or 10 mg/kg daily for 10 days). Periodontal tissue was analyzed for histopathlogy and using immunohistochemical analysis characterized the expression profiles of MMP-2, MMP-9, COX-2, and RANKL/RANK/OPG and determined the presence of IL-1β, IL-10 and TNF-α, myeloperoxidase (MPO), malonaldehyde (MDA) and, glutathione (GSH). MPO activity in the group with periodontal disease was significantly increased compared to the control group (p<0.05). Rats treated with 10 mg/kg Carvedilol presented with significantly reduced MPO and MDA concentrations (p<0.05) in addition to presenting with reduced levels of the pro-inflammatory cytokines IL-1 β and TNF-α (p<0.05). IL-10 levels in Carvedilol-treated rats remained unaltered. Immunohistochemical analysis demonstrated reduced expression of MMP-2, MMP-9, RANK, RANKL, COX-2, and OPG in rats treated with 10 mg/kg Carvedilol. This study demonstrated that Carvedilol affected bone formation/destruction and anti-inflammatory activity in a rat model of periodontitis. 相似文献
30.
Leonardo P. Farias Greice Krautz-Peterson Cibele A. Tararam Bogar O. Araujo-Montoya Tatiana R. Fraga Henrique K. Rofatto Floriano P. Silva-Jr Lourdes Isaac Akram A. Da'dara R. Alan Wilson Charles B. Shoemaker Luciana C. C. Leite 《PLoS neglected tropical diseases》2013,7(10)