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951.
Collopy-Junior I Kneipp LF da Silva FC Rodrigues ML Alviano CS Meyer-Fernandes JR 《Archives of microbiology》2006,185(5):355-362
In this work, we characterized an ecto-ATPase activity in intact mycelial forms of Fonsecaea pedrosoi, the primary causative agent of chromoblastomycosis. In the presence of 1 mM EDTA, fungal cells hydrolyzed adenosine-5′-triphosphate (ATP) at a rate of 84.6 ± 11.3 nmol Pi h−1 mg−1 mycelial dry weight. The ecto-ATPase activity was increased at about five times (498.3 ± 27.6 nmol Pi h−1 mg−1) in the presence of 5 mM MgCl2, with values of V
max and apparent K
m for Mg-ATP2−corresponding to 541.9 ± 48.6 nmol Pi h−1 mg−1 cellular dry weight and 1.9 ± 0.2 mM, respectively. The Mg2+-stimulated ecto-ATPase activity was insensitive to inhibitors of intracellular ATPases such as vanadate (P-ATPases), bafilomycin A1 (V-ATPases), and oligomycin (F-ATPases). Inhibitors of acid phosphatases (molybdate, vanadate, and fluoride) or alkaline phosphatases (levamizole) had no effect on the ecto-ATPase activity. The surface of the Mg2+-stimulated ATPase in F. pedrosoi was confirmed by assays in which 4,4′-diisothiocyanostylbene-2,2′-disulfonic acid (DIDS), a membrane impermeant inhibitor, and suramin, an inhibitor of ecto-ATPase and antagonist of P2 purinoreceptors. Based on the differential expression of ecto-ATPases in the different morphological stages of F. pedrosoi, the putative role of this enzyme in fungal biology is discussed. 相似文献
952.
Mariângela S.S. Diz André O. Carvalho Rosana Rodrigues Ana Gisele C. Neves-Ferreira Maura Da Cunha Elias Walter Alves Anna L. Okorokova-Façanha Marco Antônio Oliveira Jonas Perales Olga L.T. Machado Valdirene M. Gomes 《Biochimica et Biophysica Acta (BBA)/General Subjects》2006
During the last few years, a growing number of cysteine-rich antimicrobial peptides has been isolated from plants and particularly from seeds. It has become increasingly clear that these peptides play an important role in the protection of plants against microbial infection. In this work, proteins from chilli pepper (Capsicum annuum L.) seeds were extracted in phosphate buffer, pH 5.4 and peptides purification were performed by employing ion-exchange chromatographies on DEAE, CM-Sepharose, Sephacryl S-100 and reverse phase in HPLC. Three peptide enriched fractions, namely F1, F2 and F3, were obtained after the CM-Sepharose chromatography. The F1 fraction, mainly composed of three peptides ranging from 6 to 10 kDa, was submitted to N-terminal amino acid sequencing. The closer to 10 kDa peptide showed high sequence homology to lipid transfer proteins (LTPs) previously isolated from others seeds. F1 fraction exhibited strong fungicidal activity against Candida albicans, Saccharomyces cerevisiae and Schizosaccharomyces pombe and also promoted several morphological changes to C. albicans, including the formation of pseudohyphae, as revealed by scanning electron micrography. F1 fraction also reduced the glucose stimulated acidification of the medium mediated by H+-ATPase of S. cerevisiae cells in a dose-dependent manner and caused the permeabilization of yeast plasma membrane to the dye SYTOX Green, as verified by confocal laser microscopy. 相似文献
953.
BACKGROUND AND AIMS: Nectar production in the Bignoniaceae species lacking a nectariferous functional disc is ascribed to trichomatic glands around the ovary base and/or on the inner corolla wall. Nevertheless, knowledge about the secretion and function of these glands is very incomplete. The purpose of this paper is to study, from a developmental viewpoint, the ultrastructure, histochemistry and secretory process of the peltate trichomes on the ovary of Zeyheria montana, a species in the Bignoniaceae which has a rudimentary disc. METHODS: Samples of the gynoecium at various developmental stages were fixed and processed for light and electron microscopy. Histochemistry and cytochemistry tests were performed to examine the chemical composition of exudates. Thin layer chromatography was used to determine the presence of alkaloids and terpenes in gynoecium and fruit extracts, and in fresh nectar stored in the nectar chamber. KEY RESULTS: Peltate trichomes at different developmental stages appear side by side from floral budding up to pre-dispersal fruit. Large plastids with an extensive internal membrane system consisting of tubules filled with lipophilic material, abundant smooth endoplasmic reticulum, few Golgi bodies, lipophilic deposits in the smooth endoplasmic reticulum and mitochondria, and scattered cytoplasmic oil droplets are the main characteristics of mature head cells. The secretion which accumulates in the subcuticular space stains positively for hydrophilic and lipophilic substances, with lipids prevailing for fully peltate trichomes. Histochemistry and thin layer chromatography detected terpenes and alkaloids. Fehling's test to detect of sugars in the secretion was negative. CONCLUSIONS: The continuous presence and activity of peltate trichomes on the ovary of Z. montana from early budding through to flowering and fruiting set, and its main chemical components, alkaloids and terpenes, suggest that they serve a protective function and are not related to the floral nectar source or to improving nectar quality. 相似文献
954.
Degradation of Aroclor 1242 Dechlorination Products in Sediments by Burkholderia xenovorans LB400(ohb) and Rhodococcus sp. Strain RHA1(fcb) 总被引:1,自引:0,他引:1 下载免费PDF全文
Jorge L. M. Rodrigues C. Alan Kachel Michael R. Aiello John F. Quensen Olga V. Maltseva Tamara V. Tsoi James M. Tiedje 《Applied microbiology》2006,72(4):2476-2482
Burkholderia xenovorans strain LB400, which possesses the biphenyl pathway, was engineered to contain the oxygenolytic ortho dehalogenation (ohb) operon, allowing it to grow on 2-chlorobenzoate and to completely mineralize 2-chlorobiphenyl. A two-stage anaerobic/aerobic biotreatment process for Aroclor 1242-contaminated sediment was simulated, and the degradation activities and genetic stabilities of LB400(ohb) and the previously constructed strain RHA1(fcb), capable of growth on 4-chlorobenzoate, were monitored during the aerobic phase. The population dynamics of both strains were also followed by selective plating and real-time PCR, with comparable results; populations of both recombinants increased in the contaminated sediment. Inoculation at different cell densities (104 or 106 cells g−1 sediment) did not affect the extent of polychlorinated biphenyl (PCB) biodegradation. After 30 days, PCB removal rates for high and low inoculation densities were 57% and 54%, respectively, during the aerobic phase. 相似文献
955.
Spatial Patterns of Benthic Macroinvertebrates in Intertidal Areas of a Southern European Estuary: The Tagus, Portugal 总被引:2,自引:2,他引:0
Ana Maria Rodrigues Sónia Meireles Teresa Pereira Alice Gama Victor Quintino 《Hydrobiologia》2006,555(1):99-113
This study characterizes the composition and spatial distribution patterns of the benthic macrofauna in the intertidal mudflats
of the Tagus estuary, western Portugal. A total of 68 species, more than 226,000 specimens with a total wet weight biomass
of approximately 1170 g were identified in 380 sites. The species Streblospio shrubsolii, Cyathura carinata, Tharyx sp., Hydrobia ulvae and Tubificids were the most common and abundant. Scrobicularia plana strongly dominated the biomass. The invertebrate macrofauna of the Tagus estuary shows similarities to what is known from
other temperate mudflats. The diversity of species, their overall abundance and the ratio of Molluscs plus Crustaceans to
Polychaete species corroborate the distinctiveness between temperate and tropical mudflats and sandflats. The spatial distribution
of the fauna reflects the sediment characteristics but the relationship between the environmental and the biological data
is not as strong as obtained for sublittoral areas. This relationship diminishes from the sublittoral shelf to sublittoral
estuarine areas, showing minimum values in this study, suggesting that such a relationship is less straightforward as natural
disturbance increases. Nevertheless, a mixture of grain-size, elevation (inundation time) and particular habitats (relic oyster
beds) form the best explanatory factors for the spatial distribution patterns of the intertidal benthic macrofauna of the
Tagus estuary. 相似文献
956.
Diabetes is a significant risk factor for cardiovascular diseases with the majority of these complications being attributed to coronary vascular pathology. However, both in humans and animal models of diabetes, an additional heart muscle specific disease in the absence of any vascular pathology has also been described. Even though diverse mechanisms have been suggested to explain the etiology of this diabetic heart disease, important roles of oxidative stress and cell death have been implicated behind this disorder. Apart from hyperglycemia, cardiac lipid overload is currently believed to be responsible for oxidative stress and cell death in the diabetic heart. Although lipotoxicity is considered a major player in precipitating cardiac cell death, most of the existing work revolves around saturated and monounsaturated fatty acids. Looking at the current western diet with its preponderance of omega-6 polyunsaturated fatty acids (PUFA), more emphasis should be placed on its role in the diabetic heart. In this review, we shall highlight the most intriguing and updated findings of the differential fatty acid classes including omega-6 PUFA and their established/probable roles on diabetic myocardial cell death. 相似文献
957.
Rodrigues AP da Fonseca LM de Faria Oliveira OM Brunetti IL Ximenes VF 《Biochimica et biophysica acta》2006,1760(12):1755-1761
Horseradish peroxidase (HRP) is a plant enzyme widely used in biotechnology, including antibody-directed enzyme prodrug therapy (ADEPT). Here, we showed that HRP is able to catalyze the autoxidation of acetylacetone in the absence of hydrogen peroxide. This autoxidation led to generation of methylglyoxal and reactive oxygen species. The production of superoxide anion was evidenced by the effect of superoxide dismutase and by the generation of oxyperoxidase during the enzyme turnover. The HRP has a high specificity for acetylacetone, since the similar beta-dicarbonyls dimedon and acetoacetate were not oxidized. As this enzyme prodrug combination was highly cytotoxic for neutrophils and only requires the presence of a non-human peroxidase and acetylacetone, it might immediately be applied to research on the ADEPT techniques. The acetylacetone could be a starting point for the design of new drugs applied in HRP-related ADEPT techniques. 相似文献
958.
Rodrigues ML Archer M Martel P Miranda S Thomaz M Enguita FJ Baptista RP Pinho e Melo E Sousa N Cravador A Carrondo MA 《Biochimica et biophysica acta》2006,1764(1):110-121
The crystal structure of the elicitin beta-cinnamomin (beta-CIN) was determined in complex with ergosterol at 1.1 A resolution. beta-CIN/ergosterol complex crystallized in the monoclinic space group P2(1), with unit cell parameters of a = 31.0, b = 62.8, c = 50.0 A and beta = 93.4 degrees and two molecules in the asymmetric unit. Ligand extraction with chloroform followed by crystallographic analysis yielded a 1.35 A structure of beta-CIN (P4(3)2(1)2 space group) where the characteristic elicitin fold was kept. After incubation with cholesterol, a new complex structure was obtained, showing that the protein retains, after the extraction procedure, its ability to complex sterols. The necrotic effect of beta-CIN on tobacco was also shown to remain unchanged. Theoretical docking studies of the triterpene lupeol to beta-CIN provided an explanation for the apparent inability of beta-CIN to bind this ligand, as observed experimentally. 相似文献
959.
960.
An D Rodrigues B 《American journal of physiology. Heart and circulatory physiology》2006,291(4):H1489-H1506
In patients with diabetes, an increased risk of symptomatic heart failure usually develops in the presence of hypertension or ischemic heart disease. However, a predisposition to heart failure might also reflect the effects of underlying abnormalities in diastolic function that can occur in asymptomatic patients with diabetes alone (termed diabetic cardiomyopathy). Evidence of cardiomyopathy has also been demonstrated in animal models of both Type 1 (streptozotocin-induced diabetes) and Type 2 diabetes (Zucker diabetic fatty rats and ob/ob or db/db mice). During insulin resistance or diabetes, the heart rapidly modifies its energy metabolism, resulting in augmented fatty acid and decreased glucose consumption. Accumulating evidence suggests that this alteration of cardiac metabolism plays an important role in the development of cardiomyopathy. Hence, a better understanding of this dysregulation in cardiac substrate utilization during insulin resistance and diabetes could provide information as to potential targets for the treatment of cardiomyopathy. This review is focused on evaluating the acute and chronic regulation and dysregulation of cardiac metabolism in normal and insulin-resistant/diabetic hearts and how these changes could contribute toward the development of cardiomyopathy. 相似文献