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排序方式: 共有390条查询结果,搜索用时 15 毫秒
81.
Bruno Filippi Laura Biondi Fernando Filira Raniero Rocchi Cecilia Bellini Giampietro Sarto 《Biopolymers》1983,22(1):575-578
The synthesis in solution of some modified (D)Ala2,Leu5-enkephalins has been carried out. The lipophilic properties of the parent compound have been modified by amidation of the carboxyl function with alkylamines of increasing hydrophilicity to increase permeability of the blood-brain barrier. Attempts to reduce enzymatic degradation have been carried out either by reductive glucosamination or by amidation of the carboxyl function with 2-amino-2-deoxy-β-D-glucopyranose. Esterification of the carboxyl function of (D)Ala2,Leu5-enkephalin with polyethylenglycole 1000 has also been carried out. The effects induced by these modifications have been evaluated by in vitro and in vivo tests. 相似文献
82.
G Tedeschi A Negri F Ceciliani P A Biondi C Secchi S Ronchi 《European journal of biochemistry》1992,205(1):127-132
Chemical modification of beef kidney D-aspartate oxidase by phenylglyoxal is a biphasic process involving the transient formation of an enzymatic species with a decreased activity versus dicarboxylic substrates, an increased activity versus D-proline and a new activity versus other monocarboxylic D-amino acids which is absent in the native protein. Prolonged incubation with the modifier causes complete inactivation of the enzyme. The presence of the competitive inhibitor L-tartrate in the incubation mixture prevents enzyme inactivation. Kinetic and structural data suggest that complete loss of activity is paralleled by modification of eight arginine residues, of which two are critical for the specificity and the activity of the enzyme. We propose that the two essential arginine residues are located in the substrate binding site of D-aspartate oxidase. 相似文献
83.
A M Vaccaro I Mandara F Ciaffoni G Biondi 《Anthropologischer Anzeiger; Bericht über die biologisch-anthropologische Literatur》1984,42(4):307-314
Four Albanian and three Croatian communities settled in Molise (Italy) have been investigated for galactose-1-phosphate uridyltransferase (GALT) polymorphism. To obtain a detailed identification of each phenotype, electrophoresis and quantitative enzymatic analysis were performed on all samples. In addition to this isoelectric focusing was utilized to confirm and the D and LA variants. The gene frequencies of the different GALT alleles turned out to be: N = 0.912 (Albanians) and N = 0.868 (Croatians); G = 0.004 (Albanians); D = 0.051 (Albanians) and D = 0.081 (Croatians); LA = 0.033 (Albanians) and LA = 0.051 (Croatians). Both variants show frequencies similar to that observed in other Caucasoid populations. 相似文献
84.
G Biondi V Calabró S Colonna-Romano M Giangregorio P Malaspina R Petrucci C Santolamazza P Santolamazza E Tramontano G Battistuzzi 《Anthropologischer Anzeiger; Bericht über die biologisch-anthropologische Literatur》1989,47(2):155-174
In the present paper we report on new data of the frequency of common and rare variants in the Italian population for ADA, AK-1, 6-PGD, EsA, EsB, EsD, PGM-1, PGM-2, SOD-A, AcP, GPT, and PGI. Moreover we present a comprehensive review of the available data on the electrophoretic variants of red cell enzymes in Italians. We find a considerable degree of genetic heterogeneity between the various populations living in the Peninsula and between the population of the Peninsula and of Sardinia. We also find that the estimates of the average heterozygosity are considerably smaller for the population of Sardinia as compared to Peninsula and Sicily. Finally, we report on the occurrence of several uncommon enzyme variants, which overall frequency is very similar to previously reported estimates for North European populations (Harris et al. 1974). 相似文献
85.
E. Biondi A. Galeone N. Kuzmanović S. Ardizzi C. Lucchese A. Bertaccini 《The Annals of applied biology》2013,162(1):60-70
The rapid spreading of the disease during last few years highlighted the need of a quick, sensitive and reliable method for Pseudomonas syringae pv. actinidiae (Psa) detection, to find possible inoculum sources and limit the pathogen spreading. A PCR method, using new primers designed on the gene encoding a putative outer membrane protein P1, was developed to detect Psa in symptomatic and asymptomatic tissue; a nested‐PCR was also applied. Bleeding sap samples, collected in early spring from orchards with symptomatic and asymptomatic trees, were used both for PCR assays and for pathogen isolation and identification. The PCR and nested PCR methods were able to detect Psa presence at very low concentration from plant and pollen extracts; RFLP analyses with BclI on PCR and nested PCR amplicons confirmed the assay specificity, while the digestion with BfmI and AluI allowed to discriminate Psa strains isolated before 2008 from those isolated after 2008. Furthermore, the PCR and nested PCR on crude bleeding sap samples detected the presence of the pathogen in 3 and 5 of the 15 assayed samples, respectively. Direct isolation from the same samples and bacterial identification confirmed the results of molecular analysis. 相似文献
86.
F Cicirata R Biondi A Scrofani M Cioni 《Bollettino della Società italiana di biologia sperimentale》1983,59(9):1350-1356
The research was performed in order to study: 1) paleo and neocerebellar contributions in the sleep organization and 2) the electrical sleep activities at different time intervals during the functional compensation which follows the cerebellar lesion. Polygraphic sleep records (EEG, EMG, EOG) were performed on four subjects with surgical lesions more than 6 months old in cerebellar cortex (two subjects in paleo and two in neocerebellum). Another subject was studied before a surgical paleocerebellar lesion and at different time intervals after that (8th, 30th, 60th, and 90th day). Paleo and neocerebellar lesions showed different sleep abnormalities. The former induced both quantitative and qualitative alterations in the cyclic sleep organization, the latter did not show significant alterations in this organization but rather in transition between sleeping and waking and in sleep maintenance. The acute paleocerebellar lesion showed at the 8th and 30th day a strong reduction of the synchronized sleep (SS) and an increase of the desynchronized one (DS). In the successive records, 30th and 90th day, the SS/DS ratio increased to the values observed in the chronic paleocerebellar lesioned subjects. 相似文献
87.
Laura Lunghi Maria E Ferretti Silvia Medici Carla Biondi Fortunato Vesce 《Reproductive biology and endocrinology : RB&E》2007,5(1):6-14
The trophoblast, i.e. the peripheral part of the human conceptus, exerts a crucial role in implantation and placentation.
Both processes properly occur as a consequence of an intimate dialogue between fetal and maternal tissues, fulfilled by membrane
ligands and receptors, as well as by hormone and local factor release. During blastocyst implantation, generation of distinct
trophoblast cell types begins, namely the villous and the extravillous trophoblast, the former of which is devoted to fetal-maternal
exchanges and the latter binds the placental body to the uterine wall. Physiological placentation is characterized by the
invasion of the uterine spiral arteries by extravillous trophoblast cells arising from anchoring villi. Due to this invasion,
the arterial structure is replaced by amorphous fibrinoid material and endovascular trophoblastic cells. This transformation
establishes a low-resistance, high-capacity perfusion system from the radial arteries to the intervillous space, in which
the villous tree is embedded. The physiology of pregnancy depends upon the orderly progress of structural and functional changes
of villous and extravillous trophoblast, whereas a derangement of such processes can lead to different types of complications
of varying degrees of gravity, including possible pregnancy loss and maternal life-threatening diseases. In this review we
describe the mechanisms which regulate trophoblast differentiation, proliferation, migration and invasiveness, and the alterations
in these mechanisms which lead to pathological conditions. Furthermore, based on the growing evidence that proper inflammatory
changes and oxidative balance are needed for successful gestation, we explain the mechanisms by which agents able to influence
such processes may be useful in the prevention and treatment of pregnancy disorders. 相似文献
88.
4‐Cyano‐α‐methyl‐l‐phenylalanine as a Spectroscopic Marker for the Investigation of PeptaibioticMembrane Interactions 下载免费PDF全文
Marta De Zotti Sara Bobone Annalisa Bortolotti Edoardo Longo Barbara Biondi Cristina Peggion Fernando Formaggio Claudio Toniolo Andrea Dalla Bona Bernard Kaptein Lorenzo Stella 《化学与生物多样性》2015,12(4):513-527
Two analogs of the ten‐amino acid residue, membrane‐active lipopeptaibiotic trichogin GA IV, mono‐labeled with 4‐cyano‐α‐methyl‐L ‐phenylalanine, a potentially useful fluorescence and IR absorption probe of the local microenvironment, were synthesized by the solid‐phase methodology and conformationally characterized. The single modification was incorporated either at the N‐terminus (position 1) or near the C‐terminus (position 8) of the peptide main chain. In both cases, the replaced amino acid was the equally helicogenic α‐aminoisobutyric acid (Aib) residue. We performed a solution conformational analysis by use of FT‐IR absorption, CD, and 2D‐NMR spectroscopies. The results indicate that both labeled analogs essentially maintain the overall helical propensity of the naturally occurring lipopeptaibiotic. Peptide? membrane interactions were assessed by fluorescence and ATR‐IR absorption techniques. Analogies and differences between the two peptides were highlighted. Taken together, our data confirm literature results that some of the spectroscopic parameters of the 4‐cyanobenzyl chromophore are sensitive markers of the local microenvironment. 相似文献
89.
90.
L. Zappalà G. Siscaro A. Biondi O. Mollá J. González‐Cabrera A. Urbaneja 《Journal of Applied Entomology》2012,136(6):401-409
The South American tomato pinworm, Tuta absoluta (Meyrick), is one of the major pests of tomato crop. Since its detection in the Mediterranean basin, it has been commonly controlled using chemical insecticides. However, inoculation and conservation of predatory mirids, integrated with sprays of selective insecticides, has been demonstrated to be a cost‐effective strategy for controlling this pest. In this work, we tested the efficacy of two sulphur formulations, dustable and wettable powder, for controlling T. absoluta on tomato under greenhouse and open‐field conditions. In addition, the side effects of both sulphur formulations on the predator, Nesidiocoris tenuis (Reuter), were evaluated under laboratory conditions. Dustable sulphur, applied weekly on tomato seedlings artificially infested with T. absoluta in greenhouse conditions, significantly reduced the infestation levels and was demonstrated to have a repellent effect on oviposition. Wettable sulphur was not effective for controlling T. absoluta populations in both greenhouse and open‐field experiments. In the side effect trials conducted with N. tenuis, only dustable sulphur resulted in being moderately harmful as a fresh residue and slightly harmful as a 7‐day‐old residue; no effects were recorded exposing the predator to 14‐day‐old sulphur residues. In contrast, wettable sulphur was classified as harmless to N. tenuis. Our results suggest that the use of sulphur, especially as dustable powder, could be considered as a tool in T. absoluta management strategies, although its side effects on N. tenuis should be taken into account. The implications of these results for the use of sulphur formulations in pest and disease management programmes in tomato crops are discussed. 相似文献