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排序方式: 共有159条查询结果,搜索用时 18 毫秒
91.
Abdelhamid Mtioui Lucienne Gourdoux Robert Moreau Bernard Fournier 《Archives of insect biochemistry and physiology》1996,32(2):209-223
Adenylyl cyclase activity in mealworm larval fat body and its dependence on external Ca2+ concentrations and glucose catabolism pathways in vitro were analyzed for their response to intestinal insulin-like peptide (ILP) and synthetic locust adipokinetic hormone I (AKH-I). Dose-response curve for cAMP accumulation was obtained with increasing doses of ILP. The effects of ILP were ten-fold lower than those of AKH-I. Forskolin and IBMX provoked very high levels of cAMP accumulation but IBMX did not potentiate the effects of ILP on cAMP accumulation. Accumulation of cAMP after a treatment with ILP involves a Ca2+ influx via the opening of L-type voltage gated channels. The cyclic AMP analogue chlorophenyl thio-cAMP as well as AKH-I induced a decrease in the utilization of the pentose cycle while the effects of ILP were totally opposite. Finally, the antagonism between ILP and AKH-I on glucose metabolism results from a participation of different transduction pathways (Ca2+-dependent and Ca2+-independent, respectively), probably located in the same target cells, thus suggesting the involvement of mechanisms similar to those existing in mammals. © 1996 Wiley-Liss, Inc. 相似文献
92.
S Lewicka J Winter V D Bokkenheuser P Vecsei S Abdelhamid U Heinrich 《Journal of steroid biochemistry》1986,24(2):581-586
A radioimmunoassay of 21-deoxytetrahydroaldosterone was developed. Normal daily excretion of the unconjugated metabolite was 1.2 +/- 1.3 micrograms and of the glucuronized metabolite, 11.9 +/- 7 micrograms. The tetrahydroaldosterone/21-deoxytetrahydroaldosterone ratio varied more in patients with primary aldosteronism than in control subjects. Thus, measurements of the urinary excretion of the tetrahydroaldosterone or 21-deoxytetrahydroaldosterone alone did not provide an accurate expression for aldosterone production. Their sum correlated well with the clinical condition, i.e. clear-cut elevation in patients with primary aldosteronism. The diminished tetrahydroaldosterone/21-deoxytetrahydroaldosterone ratio found in patients with 21-hydroxylase deficiency may be attributed to increased bacterial conversion of tetrahydroaldosterone to 21-deoxytetrahydroaldosterone but could also stem from a deficiency implicating zona glomerulosa (aldosterone biosynthesis) regardless of the stage and clinical presentation of the disease. 相似文献
93.
Manar Hassan Mahmoud Abdelhamid Olodia Aied Nassef Mohamed Abdel Harith 《Soil & Sediment Contamination》2018,27(6):485-500
Total Petroleum Hydrocarbons (TPH) are one of the most common groups of persistent environmental toxic organic contaminants to many organisms as well as to humans. In the present work, oil-polluted soil samples were phyto-remediated and analyzed. The investigated soil samples were collected from a location close to the oil petroleum production site in Ras-Gharib, Red Sea, Egypt. The phytoremediation process through TPH reduction and/or removal was carried out using Helianthus annuus (sunflower plant) based on its efficiency as a phytoremediator for organic pollutants. A preliminary four-week scheme of Helianthus annuus remediation, supported by twice quantized fertilization, provided a result of ~56% clean soil. Contaminated and phyto-remediated samples were diagnosed and analyzed through particle size distribution, Carbon-Hydrogen-Sulfur-Nitrogen elemental analysis (CHSN), Organic Matter content (OM%), Total Petroleum Hydrocarbons determination (%) and spectroscopically through Laser Induced Breakdown Spectroscopy (LIBS) and Laser Induced Fluorescence (LIF). Promising results have been achieved indicating the feasibility of planting sunflower for effective TPH remediation of the polluted soil and also the possibility of in situ monitoring of the remediation with easy, cost effective and fast spectrochemical analytical techniques, namely LIBS and LIF. 相似文献
94.
Eloualid A Abidi O Charif M El Houate B Benrahma H Louanjli N Chadli E Ajjemami M Barakat A Bashamboo A McElreavey K Rhaissi H Rouba H 《PloS one》2012,7(3):e34111
The methylenetetrahydrofolate reductase (MTHFR) gene is one of the main regulatory enzymes involved in folate metabolism, DNA synthesis and remethylation reactions. The influence of MTHFR variants on male infertility is not completely understood. The objective of this study was to analyze the distribution of the MTHFR C677T and A1298C variants using PCR-Restriction Fragment Length Polymorphism (RFLP) in a case group consisting of 344 men with unexplained reduced sperm counts compared to 617 ancestry-matched fertile or normozoospermic controls. The Chi square test was used to analyze the genotype distributions of MTHFR polymorphisms. Our data indicated a lack of association of the C677T variant with infertility. However, the homozygous (C/C) A1298C polymorphism of the MTHFR gene was present at a statistically high significance in severe oligozoospermia group compared with controls (OR = 3.372, 95% confidence interval CI = 1.27–8.238; p = 0.01431). The genotype distribution of the A1298C variants showed significant deviation from the expected Hardy-Weinberg equilibrium, suggesting that purifying selection may be acting on the 1298CC genotype. Further studies are necessary to determine the influence of the environment, especially the consumption of diet folate on sperm counts of men with different MTHFR variants. 相似文献
95.
Through monthly samplings of grasshoppers taken from five sites in oases and two in steppes in the area of Biskra, 45 species could be recorded. Four assemblages of species can be defined, two in the oasian zones, one in the stony steppe and a last one in the sandy steppe. The two oasian assemblages are interpreted in the light of a gradient of salinity and humidity determined by the vegetation. In each type of steppe, there is a spring sub-assemblage and a summer-autumnal one, but such a distinction is not possible in the anthropised sites. The steppe stations are moreover characterized by a larger diversity determined by the Shannon index and a weaker density than in the oases, in spite of a comparable richness. The comparative analysis of species phenology between the different assemblages allows discussing their adaptation toward seasonal variations of dryness in these arid environments. 相似文献
96.
Senda Kahloul Imen HajSalah El Beji Aurélia Boulaflous Ali Ferchichi Hongzhi Kong Said Mouzeyar Mohamed Fouad Bouzidi 《DNA research》2013,20(1):67-78
The degradation of proteins by the 26S proteasome is initiated by protein polyubiquitination mediated by a three-step cascade. The specific ubiquitination of different target proteins is mediated by different classes of E3 ubiquitin ligases, among which the best known are Skp1-Cullin-F-box complexes. Whereas protists, fungi and some vertebrates have a single SKP1 gene, many animal and plant species possess multiple SKP1 homologues. In this paper, we report on the structure, phylogeny and expression of the complete set of rice SKP1 genes (OSKs, Oryza sativa SKP1-like genes). Our analyses indicated that OSK1 and OSK20 belong to a class of SKP1 genes that contain one intron at a conserved position and are highly expressed. In addition, our yeast two-hybrid results revealed that OSK proteins display a differing ability to interact with F-box proteins. However, OSK1 and OSK20 seemed to interact with most of the nine F-box proteins tested. We suggest that rice OSK1 and OSK20 are likely to have functions similar to the Arabidopsis ASK1 and ASK2 genes. 相似文献
97.
98.
Amel ben Anes Hamadi Fetoui Sarra Bchir Hela ben Nasr Hassiba Chahdoura Elyes Chabchoub Saloua Yacoub Abdelhamid Garrouch Mohamed Benzarti Zouhair Tabka Karim Chahed 《Biological trace element research》2014,161(1):20-31
This study was aimed to evaluate the oxidant–antioxidant imbalance in the pathogenesis of chronic obstructive pulmonary disease (COPD) in Tunisians. We assessed 16 parameters related to the oxidative status that include malondialdehyde (MDA), total protein carbonyls (PCs), and advanced oxidation protein products (AOPP). We also examined the activity of glutathione peroxydase (GSH-Px), catalase, and superoxide dismutase (SOD) in the plasma and erythrocytes. Levels of total thiols, reduced glutathione (GSH), total antioxidant status (TAS), hydrogen peroxide, ascorbic acid, iron, and protein sulfhydryls were determined using spectrophotometry. We also evaluated the level of nitric oxide (NO) and peroxynitrite in plasma from COPD patients and healthy controls. Estimation of DNA damage was determined using the comet assay. Pulmonary functional tests were performed by body plethysmography. Levels of MDA, PC, DNA damage, and AOPP were significantly increased while total thiols, GSH, and TAS were decreased in COPD patients. GSH-Px activity was higher in COPD patients while no difference was found for catalase and SOD. We also observed a lower level of NO and peroxynitrite in COPD patients. Decreased levels of peroxynitrite were found to correlate with disease progression, as well as with forced expiratory volume in 1 s/forced vital capacity among COPD patients. Multivariate analysis revealed that NO is associated with pathological pathways that help to predict patient outcome independently of the degree of airflow obstruction. These results indicate the presence of a systemic oxidative stress and highlight the importance of NO and peroxynitrite as major effectors in COPD development and airflow obstruction. 相似文献
99.
100.
Josef Deutscher Francine Moussan Désirée Aké Meriem Derkaoui Arthur Constant Zébré Thanh Nguyen Cao Houda Bouraoui Takfarinas Kentache Abdelhamid Mokhtari Eliane Milohanic Philippe Joyet 《Microbiology and molecular biology reviews》2014,78(2):231-256