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排序方式: 共有381条查询结果,搜索用时 8 毫秒
371.
Sprong T van der Ley P Steeghs L Taw WJ Verver-Janssen TJ Netea MG van der Meer JW van Deuren M 《European cytokine network》2002,13(4):411-417
Fulminant meningococcal sepsis (FMS) is considered the prototypical Gram-negative sepsis. Lipopolysaccharide (LPS) is thought to be the main toxic element that induces pro-inflammatory cytokine production after interaction with CD14 and toll-like receptor 4 (TLR4). However, there is increasing evidence that LPS is not the sole toxic element of meningococci. The aim of the present study was to determine the role of CD14 and TLR4 in pro-inflammatory cytokine induction by meningococci. To this end, cytokine induction by isolated meningoccal LPS, wild-type N. meningitidis H44/76 (LPS+-meningococci) matched for concentrations of LPS and LPS-deficient N. meningitidis H44/76lpxA (LPS - -meningococci) was studied in human PBMCs and murine peritoneal macrophages (PMs). Pre-incubation of PBMCs with WT14, a monoclonal antibody against CD14, abolished TNF-alpha and IL-1beta induction by E. coli LPS, while cytokine induction by meningococcal LPS was only partially inhibited. When LPS+- and LPS - -meningococci at higher concentrations were used as stimuli, anti-CD14 had a minimal effect. In C3H/HeJ murine PMs, devoid of a functional TLR4, minimal IL-1alpha, IL-6 and TNF-alpha production was seen after stimulation with 10 ng/mL E. coli or meningococcal LPS. However, at higher concentrations (1000 ng LPS/mL) the production of TNF-alpha, but not IL-1alpha or IL-6, occurred also independently of TLR4. The expression of a functional TLR4 in murine PMs had no effect on the cytokine induction by LPS+- or LPS - -meningococci. It is concluded that pro-inflammatory cytokine induction by N. meningitidis can occur independently of CD14 and TLR4. 相似文献
372.
Ziouzenkova O Asatryan L Tetta C Wratten ML Hwang J Sevanian A 《Free radical biology & medicine》2002,33(2):248-258
The high cardiovascular mortality in patients receiving hemodialysis (HD) has been attributed, in part, to oxidative stress. Here we examined the effectiveness of antioxidants introduced by means of a novel hemolipodialysis (HLD) procedure in terms of reducing oxidative stress during ex vivo blood circulation. Oxidative stress was studied in a model HD system resembling the extracorporeal circulation of blood during clinical HD. Blood circulation produced an increase of up to 280% in free hemoglobin levels and an increase of 320% in electronegative LDL (LDL(-)) subfraction. A significant correlation between LDL(-) and free hemoglobin levels confirmed previous findings that LDL(-) formation during ex vivo circulation of blood can be mediated by the oxidative activity of free hemoglobin. These effects were significantly attenuated during HLD using a dialysis circuit containing vitamin E with or without vitamin C. By contrast, HLD with vitamin C alone had a marked pro-oxidant effect. TBARS, lipid hydroperoxides, vitamin E and beta-carotene content in LDL were not significantly altered by the HD procedure. These findings demonstrate the occurrence of oxidative stress in human plasma where lipoproteins are a target and indicate antioxidant-HLD treatment as a specific new approach to decreasing the adverse oxidative stress frequently associated with cardiovascular complications in high-risk populations of uremic patients. 相似文献
373.
Justin P. Suraci Michael Clinchy Liana Y. Zanette Christopher C. Wilmers 《Ecology letters》2019,22(10):1578-1586
Apex predators such as large carnivores can have cascading, landscape‐scale impacts across wildlife communities, which could result largely from the fear they inspire, although this has yet to be experimentally demonstrated. Humans have supplanted large carnivores as apex predators in many systems, and similarly pervasive impacts may now result from fear of the human ‘super predator’. We conducted a landscape‐scale playback experiment demonstrating that the sound of humans speaking generates a landscape of fear with pervasive effects across wildlife communities. Large carnivores avoided human voices and moved more cautiously when hearing humans, while medium‐sized carnivores became more elusive and reduced foraging. Small mammals evidently benefited, increasing habitat use and foraging. Thus, just the sound of a predator can have landscape‐scale effects at multiple trophic levels. Our results indicate that many of the globally observed impacts on wildlife attributed to anthropogenic activity may be explained by fear of humans. 相似文献
374.
375.
Burton R. Andersen Liana Harvath 《Biochimica et Biophysica Acta (BBA)/General Subjects》1979,584(1):164-173
A simple chemical system consisting of FeSO4 and H2O2 (Fenton's reagent) was shown to emit light (chemiluminescence). The addition of tryptophan to the reaction markedly enhanced light production. Very little chemiluminescence was observed when H2O2 was omitted from the reaction and when ferric, instead of ferrous, ions were used. Hydroxyl radical (OH.) and singlet oxygen (1ΔgO2) quenchers suppressed chemiluminescence of the FeSO4 + tryptophan + H2O2 system; and, deuterium oxide (2H2O) enhanced chemiluminescence of both FeSO4 reactions. These observations suggest that a radical chain reaction involving both OH. and 1ΔgO2 is responsible for the chemiluminescent reactions. Six iron-containing proteins, some of which are located within granulocytes, all emitted light in the presence of H2O2. Since iron and H2O2 are present in metabolically stimulated granulocytes, it is likely that chemiluminescent reactions similar to the ones demonstrated in this study account for part of the chemiluminescence of activated granulocytes. 相似文献
376.
377.
First experience in clinical application of hyperspectral endoscopy for evaluation of colonic polyps
Jonghee Yoon James Joseph Dale J. Waterhouse Charlie Borzy Kyla Siemens Sarah Diamond Vassiliki Liana Tsikitis Sarah E. Bohndiek 《Journal of biophotonics》2021,14(9):e202100078
Early detection and resection of adenomatous polyps prevents their progression to colorectal cancer (CRC), significantly improving patient outcomes. Polyps are typically identified and removed during white-light colonoscopy. Unfortunately, the rate of interval cancers that arise between CRC screening events remains high, linked to poor visualization of polyps during screening and incomplete polyp removal. Here, we sought to evaluate the potential of a hyperspectral endoscope (HySE) to enhance polyp discrimination for detection and resection. We designed, built and tested a new compact HySE in a proof-of-concept clinical study. We successfully collected spectra from three tissue types in seven patients undergoing routine colonoscopy screening. The acquired spectral data from normal tissue and polyps, both pre- and post- resection, were subjected to quantitative analysis using spectral angle mapping and machine learning, which discriminated the data by tissue type, meriting further investigation of HySE as a clinical tool. 相似文献
378.
Abstract The effect of various substances on parasitic protozoa was tested on Eucoccidium dinophili , which is a specific parasite in archiannelidium Dinophilus gyrociliatus . Most of the tested substances were toxic for the host, and inactive against Eucoccidium . Seven of the tested substances caused a delay and two of them caused a complete inhibition of the infection. 相似文献
379.
Liana Harvath Janis K. Lazdins Enrica Alteri Edward J. Leonard 《Biochemical and biophysical research communications》1982,108(1):392-398
Human peripheral blood monocytes comprise two subpopulations. Whereas one subpopulation migrates to a variety of chemoattractants , the remaining subpopulation fails to respond to chemoattractants. The subpopulations were isolated with a chemotaxis separation chamber and their superoxide generation was studied. Superoxide production was continuously monitored during monocyte exposure to phorbol myristate acetate, N-formyl-methionyl-leucyl-phenylalanine and N-formyl-norleucyl-leucyl-phenylalanine. Superoxide production by nonmigrating monocytes was less than 33% of the migrating subpopulations' production. Thus, the subpopulation of monocytes which fails to migrate to chemoattractants also demonstrates defective superoxide production. 相似文献
380.