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991.
François Biollaz Nadia Bruyndonckx Grégory Beuneux Mauro Mucedda Jérôme Goudet Philippe Christe 《Journal of Biogeography》2010,37(8):1557-1569
Aim We investigate the population genetic structure of the Maghrebian bat, Myotis punicus, between the mainland and islands to assess the island colonization pattern and current gene flow between nearby islands and within the mainland. Location North Africa and the Mediterranean islands of Corsica and Sardinia. Methods We sequenced part of the control region (HVII) of 79 bats across 11 colonies. The phylogeographical pattern was assessed by analysing molecular diversity indices, examining differentiation among populations and estimating divergence time. In addition, we genotyped 182 bats across 10 colonies at seven microsatellite loci. We used analysis of molecular variance and a Bayesian approach to infer nuclear population structure. Finally, we estimated sex‐specific dispersal between Corsica and Sardinia. Results Mitochondrial analyses indicated that colonies between Corsica, Sardinia and North Africa are highly differentiated. Within islands there was no difference between colonies, while at the continental level Moroccan and Tunisian populations were highly differentiated. Analyses with seven microsatellite loci showed a similar pattern. The sole difference was the lack of nuclear differentiation between populations in North Africa, suggesting a male‐biased dispersal over the continental area. The divergence time of Sardinian and Corsican populations was estimated to date back to the early and mid‐Pleistocene. Main conclusions Island colonization by the Maghrebian bats seems to have occurred in a stepping‐stone manner and certainly pre‐dated human colonization. Currently, open water seems to prevent exchange of bats between the two islands, despite their ability to fly and the narrowness of the strait of Bonifacio. Corsican and Sardinian populations are thus currently isolated from any continental gene pool and must therefore be considered as different evolutionarily significant units (ESU). 相似文献
992.
Nadia Ponts Leslie Couedelo Laetitia Pinson-Gadais Marie-Noëlle Verdal-Bonnin Christian Barreau & Florence Richard-Forget 《FEMS microbiology letters》2009,293(2):255-262
The present study aims at clarifying the impact of oxidative stress on type B trichothecene production. The responses to hydrogen peroxide (H2 O2 ) of an array of Fusarium graminearum and Fusarium culmorum strains were compared, both species carrying either the chemotype deoxynivalenol (DON) or nivalenol (NIV). In both cases, levels of in vitro toxin production are greatly influenced by the oxidative parameters of the medium. A 0.5 mM H2 O2 stress induces a two- to 50-fold enhancement of DON and acetyldeoxynivalenol production, whereas the same treatment results in a 2.4- to sevenfold decrease in NIV and fusarenone X accumulation. Different effects of oxidative stress on toxin production are the result of a variation in Fusarium 's antioxidant defence responses according to the chemotype of the isolate. Compared with DON strains, NIV isolates have a higher H2 O2 -destroying capacity, which partially results from a significant enhancement of catalase activity induced by peroxide stress. A 0.5 mM H2 O2 treatment leads to a 1.3- to 1.7-fold increase in the catalase activity of NIV isolates. Our data, which show the higher adaptation to oxidative stress developed by NIV isolates, are consistent with the higher virulence of these Fusarium strains on maize compared with DON isolates. 相似文献
993.
Paolo de Girolamo Nadia Arcamone Annamaria Rosica G. Gargiulo 《Cell and tissue research》1998,293(3):567-571
Pituitary adenylate cyclase-activating peptide (PACAP) is a novel vasoactive intestinal peptide (VIP)-like peptide isolated from ovine hypothalamus. It is present in neuronal elements of a number of peripheral organs. We have examined whether PACAP occurs in the gill arch of Carassius auratus L. in which our recent studies have shown the presence of VIP-like peptide. Immunohistochemistry has revealed PACAP-like immunoreactivity in the anterior branches of the post-trematic glossopharyngeal and vagus nerves. PACAP-immunoreactive nerve cell bodies and fibers are present in connective tissue on the oral side of the gill arch. Colocalization studies carried out by the application of double immunofluorescence show that a PACAP-like peptide coexists with VIP in the same nerve cell bodies and fibers. The localization pattern of PACAP in the gill arch of goldfish suggests its possible involvement in the regulation of secretory activities. 相似文献
994.
Substitution of an Alanine Residue for Glycine 146 in TMP Kinase from Escherichia coli Is Responsible for Bacterial Hypersensitivity to Bromodeoxyuridine
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Lise Tourneux Nadia Bucurenci Ioan Lascu Hiroshi Sakamoto Gilbert Briand Anne-Marie Gilles 《Journal of bacteriology》1998,180(16):4291-4293
The wild-type TMP kinases from Escherichia coli and from a strain hypersensitive to 5-bromo-2′-deoxyuridine were characterized comparatively. The mutation at codon 146 causes the substitution of an alanine residue for glycine in the enzyme, which is accompanied by changes in the relative affinities for 5-Br-UMP and TMP compared to those of the wild-type TMP kinase. Plasmids carrying the wild-type tmk gene from Escherichia coli or Bacillus subtilis, but not the defective tmk gene, restored the resistance to bromodeoxyuridine of an E. coli mutant strain. 相似文献
995.
Nadia B. Fröbisch Jennifer C. Olori Rainer R. Schoch Florian Witzmann 《Seminars in cell & developmental biology》2010,21(4):424-431
Ontogenetic series of extinct taxa are extremely rare and when preserved often incomplete and difficult to interpret. However, the fossil record of amphibians includes a number of well-preserved ontogenetic sequences for temnospondyl and lepospondyl taxa, which have provided valuable information about the development of these extinct groups. Here we summarize the current knowledge on fossil ontogenies of amphibians, their potential and limitations for relationship assessments, and discuss the insights they have provided for our understanding of the anatomy, life history, and ecology of extinct amphibians. 相似文献
996.
997.
Nadia Chowhan Aditi Shreeya Bali Harminder Pal Singh Daizy R. Batish Ravinder Kumar Kohli 《Acta Physiologiae Plantarum》2014,36(12):3137-3146
We investigated the effect of β-pinene on reactive oxygen species (ROS: lipid peroxidation, membrane integrity, hydrogen peroxide and superoxide ions) generation and activity of antioxidant defense system during early hours of treatment (4, 8, 16 and 24 h) in hydroponically grown Triticum aestivum (wheat). β-Pinene reduced the root and shoot growth of the hydroponically grown wheat. However, the reduction was more pronounced in root length than in shoot length. β-Pinene enhanced ROS generation as indicated by increased levels of malondialdehyde (20–87 %), hydrogen peroxide (9–45 %) and superoxide ion (23–179 %) content, thereby suggesting lipid peroxidation and induction of oxidative stress in a time- and concentration-dependent manner. The oxidative damage was more pronounced at ≥10 µM β-pinene and at ≥8 h after exposure. β-Pinene caused a severe electrolyte leakage from wheat roots indicating membrane disruption and loss of integrity. Enhanced lipid peroxidation and loss of membrane integrity were confirmed by in situ histochemical studies. β-Pinene provoked increase in the activity of lipoxygenase and upregulation in the activities of antioxidant enzymes: catalases, superoxide dismutases, ascorbate peroxidases, guaiacol peroxidases and glutathione reductases. The enhanced activity of lipoxygenases evoked by β-pinene paralleled higher accumulation of MDA, thereby suggesting that antioxidant defense mechanism was not able to prevent β-pinene-induced lipid peroxidation. 相似文献
998.
Leonardo Sorci Lucia Brunetti Lucia Cialabrini Francesca Mazzola Marat D. Kazanov Sabato D’Auria Silverio Ruggieri Nadia Raffaelli 《FEBS letters》2014
NMN deamidase (PncC) is a bacterial enzyme involved in NAD biosynthesis. We have previously demonstrated that PncC is structurally distinct from other known amidohydrolases. Here, we extended PncC characterization by mutating all potential catalytic residues and assessing their individual roles in catalysis through kinetic analyses. Inspection of these residues’ spatial arrangement in the active site, allowed us to conclude that PncC is a serine-amidohydrolase, employing a Ser/Lys dyad for catalysis. Analysis of the PncC structure in complex with a modeled NMN substrate supported our conclusion, and enabled us to propose the catalytic mechanism. 相似文献
999.
Nadia Jrad-Battikh Amira Souii Rym Hadhri Mahjoub Aouni Jawhar Gharbi Manel Ben M’hadheb-Gharbi 《Biologia》2014,69(1):113-121
We have previously addressed the question of whether the attenuating mutations of domain V of the Poliovirus IRES were specific for a given genomic context or whether they could be extrapolated to a genomic related virus, the Coxsackievirus B3 (CVB3). Accordingly, we have described that Sabin3-like mutation (U473→C) introduced in the CVB3 genome led to a defective mutant with a serious reduction in translation efficiency. In this study, we assessed the protection provided by the Sabin3-like mutant against CVB3 infection. For this purpose, we analyzed, in vivo, the Sabin3-like phenotype in Swiss mice inoculated with CVB3 and CVB4 E2 prototype strains either by oral or intraperitoneal (i.p) routes and explored the capacity of this mutant to act as a vaccine vector after the challenge. The Sabin3-like RNA was detected by semi-nested PCR in different organs: heart, pancreas and intestine at 10 days post-inoculation with both oral and i.p routes. Additionally, we did not observe any histological alterations in heart and intestine tissues. RNA was detected in the different organs of all mice immunized with the Sabin3-like strain and challenged with either CVB3 or CVB4 E2 by oral route at 7 days post-challenge. In contrast, no histological alteration of heart or pancreas tissues was observed after challenge with both wild-strains. Interestingly, the detection of viral RNA in heart, pancreas and intestine of mice immunized by i.p route was negative at 7 days post-challenge with CVB3 and CVB4 E2, and mice were protected from myocarditis and pancreatitis. 相似文献
1000.
Boris Schwartz Mohamed Amine Benadjaoud Enora Cléro Nadia Haddy Chiraz El-Fayech Catherine Guibout Cécile Teinturier Odile Oberlin Cristina Veres Hélène Pacquement Martine Munzer Tan Dat N’Guyen Pierre-Yves Bondiau Delphine Berchery Anne Laprie Mike Hawkins David Winter Dimitri Lefkopoulos Jean Chavaudra Carole Rubino Ibrahima Diallo Jacques Bénichou Florent de Vathaire 《Radiation and environmental biophysics》2014,53(2):381-390
Bone sarcoma as a second malignancy is rare but highly fatal. The present knowledge about radiation-absorbed organ dose–response is insufficient to predict the risks induced by radiation therapy techniques. The objective of the present study was to assess the treatment-induced risk for bone sarcoma following a childhood cancer and particularly the related risk of radiotherapy. Therefore, a retrospective cohort of 4,171 survivors of a solid childhood cancer treated between 1942 and 1986 in France and Britain has been followed prospectively. We collected detailed information on treatments received during childhood cancer. Additionally, an innovative methodology has been developed to evaluate the dose–response relationship between bone sarcoma and radiation dose throughout this cohort. The median follow-up was 26 years, and 39 patients had developed bone sarcoma. It was found that the overall incidence was 45-fold higher [standardized incidence ratio 44.8, 95 % confidence interval (CI) 31.0–59.8] than expected from the general population, and the absolute excess risk was 35.1 per 100,000 person-years (95 % CI 24.0–47.1). The risk of bone sarcoma increased slowly up to a cumulative radiation organ absorbed dose of 15 Gy [hazard ratio (HR) = 8.2, 95 % CI 1.6–42.9] and then strongly increased for higher radiation doses (HR for 30 Gy or more 117.9, 95 % CI 36.5–380.6), compared with patients not treated with radiotherapy. A linear model with an excess relative risk per Gy of 1.77 (95 % CI 0.6213–5.935) provided a close fit to the data. These findings have important therapeutic implications: Lowering the radiation dose to the bones should reduce the incidence of secondary bone sarcomas. Other therapeutic solutions should be preferred to radiotherapy in bone sarcoma-sensitive areas. 相似文献