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281.
The cytogenetic effect of malathion residues in wheat grains stored for different periods of time (4, 12, 24 weeks) was evaluated in Swiss mice. The studies included: (1) chromosomal aberrations analysis in bone-marrow and spermatocyte cells; (2) chromosomal aberrations and sister chromatid exchange (SCE) analysis in spleen cell culture from mice fed with stored wheat grains. The tested doses were 8.36 (applied dose), 25.08 and 41.80 mg malathion kg(-1) wheat grains. The results demonstrated that the cytogenetic effect induced in different mouse tissues by malathion residues was dose-dependent and increased with increasing of both feeding and storage periods.Feeding mice with wheat grains stored for 4 weeks had a non-significant effect with respect to the induction of chromosomal aberrations or SCEs. Significant chromosome damage and increase of SCEs were observed in mice fed with wheat grains stored for 12 weeks. The maximum effect was recorded in mice fed for 12 weeks with the grains treated with the highest tested dose and stored for 24 weeks. However, mitomycin C i.p.-injected in mice at 1 mg kg(-1) body weight (b.w.) (positive control) induced a higher effect. The percentage of chromosome aberrations reached 13.60+/-0.98, 13.60+/-0.77 and 11.73+/-0.98 (P<0.01) in bone-marrow, cultured spleen cells and spermatocytes, respectively. The significant increase of abnormalities in spermatocytes was seen for univalent formation only, predominantly of the sex chromosomes. The frequency of SCEs was 10.76+/-0.62 per cell (P<0.01) in cultured spleen cells compared with 5.46+/-0.45 per cell for control and 14.66+/-0.54 per cell for the positive control.The obtained results indicate that malathion residues in stored wheat grains have potential genotoxic effect in mice under the conditions tested.  相似文献   
282.
The enzyme sterol 24-C-methyltransferase (SMT) belongs to the family of transferases, specifically to the one-carbon transferring methyltransferases. SMT has been found playing a major role during the production of steroids, especially for the biosynthesis of ergosterol, which is the major membrane sterol in leishmania parasites, causing leishmaniasis. However, SMT and ergosterol are not found in mammals, so, an extensive study has been carried out over the susceptible SMT protein, which is found to be highly conserved among all the Leishmania species and holds a significant anti-leishmanial drug target. To date, there is no computational data available for SMT, due to its highly unexplored profile. In this work, a complete set of structural attributes have been examined through the available computational procedures, along with an attempt to characterize the most capable modeling server available. The exploration ranges from physicochemical characterization, pairwise alignment, secondary structure prediction, to active site detection. With this information, a docking study was carried out to find the compound that best binds into the active site. Moreover, molecular dynamics simulation was conducted to examine the stability of the homology modeled protein and the ligand–enzyme complex. The results indicate that the ligand–enzyme complex is more stable.  相似文献   
283.
Bone repair after trauma or surgical intervention involves a tightly regulated cascade of events that starts with hemostasis and an inflammatory response, which are critical for successful healing. Nonsteroidal anti-inflammatory drugs (NSAID) are routinely prescribed for pain relief despite their potential inhibitory effect on bone repair. The goal of this study was to determine the impact of administration of the non-selective NSAID diclofenac in the inflammatory phase of bone repair in mice with or without lipopolysaccharide-induced systemic inflammation. Repair of femoral window defects was characterized using micro computed tomography imaging and histological analyses at 2 weeks postoperative. The data indicate (a) impaired bone regeneration associated with reduced osteoblast, osteoclast, and macrophage activity; (b) changes in the number, activity, and distribution of mast cells in regenerating bone; and (c) impaired angiogenesis due to a direct toxic effect of diclofenac on vascular endothelial cells. The results of this study provide strong evidence to support the conjecture that administration of NSAIDs in the first 2 weeks after orthopaedic surgery disrupts the healing cascade and exacerbates the negative effects of systemic inflammation on the repair process.  相似文献   
284.
Bee products have been used since ancient times to treat many diseases, including respiratory ailments. The present study aimed to examine the modulatory effect of honey, royal jelly, and propolis extract on peripheral blood leukocytes and lung inflammation in a mouse conalbumin-induced asthma model. The mice in group I were not sensitised or treated; they were kept as controls. The mice in group II were sensitised and challenged with conalbumin. Twenty-four hours after the first challenge with antigen, the mice in group III received 0.5 mg/kg of dexamethasone intraperitoneally per day for 18 consecutive days and kept as positive controls. The mice in groups IV, V, and VI received 650, 1000, and 30 mg/kg of honey, royal jelly, and propolis (aqueous and ethanolic extract), respectively, once per day for 18 consecutive days. Blood was collected from all of the mice for white blood cell differentiation, and the lungs were removed for histopathological studies. The groups treated with propolis extract exhibited considerable ameliorative effects against asthma, which might be explained by the flavonoids and phenolics found in propolis, which might have antioxidative effects. Otherwise, the sensitised and honey- or royal jelly-treated groups exhibited an increased incidence of asthma cascade events due to increased inflammatory cells. These results might be due to the immunostimulatory and vasodilatory effects of royal jelly and honey, which are antagonistic to bronchial asthma cases. Histopathological examination revealed that the sensitised treated propolis extract groups had significant decreases in inflammatory scores compared with other treatments and the sensitised untreated group. These results confirmed the previous data of peripheral blood cells.  相似文献   
285.
This study was conducted on 100 one-day-old broiler chicks to evaluate the effect of Poulvac E. coli vaccine in reduction of clinical signs and complications after concurrent infectious bronchitis virus (variant 02) and virulent E. coli O78 challenges. The birds were evaluated for clinical signs, mortality for 7?days post-infection, PM lesion score, average body weight and serological evaluation. Re-isolation and RT-PCR for the challenging infectious bronchitis virus (IBV) variant 02 were conducted thereafter. The results showed that the Poulvac E. coli at one-day old chicks in the presence of co-infection with virulent E. coli and IBV variant 02 provides better body weight gain at 35?days than the other groups. The challenge with IBV variant 02 alone in non-vaccinated birds doesn’t give any mortality; this indicated that the severity of IBV variant 02 increased by the presence of co-infection with Avian Pathogenic E. coli (APEc). The mortality percentage associated with both E. coli and IBV variant 02 infections in the none vaccinated group by Poulvac E. coli was 25% while this percentage was 10% of the vaccinated group. The Poulvac E. coli is not negatively affecting the immune response against different concurrent viral vaccines like Infectious bursal disease (IBD), and moreover, it improves the immune response against some others like Newcastle disease virus (NDV), Avian Influenza (AI) H5 and IBV.  相似文献   
286.
Uterine leiomyoma (UL) is the most common gynaecologic tumour, affecting an estimated 70 to 80% of women. Leiomyomas develop from the transformation of myometrial stem cells into leiomyoma stem (or tumour‐initiating) cells. These cells undergo self‐renewal and differentiation to mature cells, both are necessary for the maintenance of tumour stem cell niche and tumour growth, respectively. Wnt/β‐catenin and TGF‐β/SMAD pathways, both overactive in UL, promote stem cell self‐renewal, crosstalk between stem and mature cells, cellular proliferation, extracellular matrix (ECM) accumulation and drive overall UL growth. Recent evidence suggests that simvastatin, an antihyperlipidemic drug, may have anti‐leiomyoma properties. Herein, we investigated the effects of simvastatin on UL stem cells. We isolated leiomyoma stem cells by flow cytometry using DyeCycle Violet staining and Stro‐1/CD44 surface markers. We found that simvastatin inhibits proliferation and induces apoptosis in UL stem cells. In addition, it also suppressed the expression of the stemness markers Nanog, Oct4 and Sox2. Simvastatin significantly decreased the production of the key ECM proteins, collagen 1 and fibronectin. Finally, it inhibited genes and/or proteins expression of TGF‐β1, 2 and 3, SMAD2, SMAD4, Wnt4, β‐Catenin, LRP6, AXIN2 and Cyclin D1 in UL stem cells, all are key drivers of the TGF‐β3/SMAD2 and Wnt4/β‐Catenin pathways. Thus, we have identified a novel stem cell‐targeting anti‐leiomyoma simvastatin effect. Further studies are needed to replicate these findings in vivo.  相似文献   
287.
Nanotechnology has received much attention because of its distinctive properties and many applications in various fields. Nanotechnology is a new approach to increase agricultural production with premium quality, environmental safety, biological support, and financial stability. Ecofriendly technology is becoming progressively important in modern agricultural applications as alternatives to traditional fertilizers and pesticides. Nanotechnology offers an alternative solution to overcome the disadvantages of conventional agriculture. Therefore, recent developments in using nanoparticles (NPs) in agriculture should be studied. This review presented a novel overview about the biosynthesis of NPs, using NPs as nano-fertilizers and nano-pesticides, the applications of NPs in agriculture, and their role in enhancing the function of biofactors. We also, show recent studies on NPs-plant interactions, the fate and safety of nanomaterials in plants, and NPs' function in alleviating the adverse effects of abiotic stress and heavy metal toxicity. Nano-fertilizers are essential to reduce the use of inorganic fertilizers and reduce their antagonistic effects on the environment. Nano-fertilizers are more reactive, can penetrate the epidermis allowing for gradual release, and targeted distribution, and thus reducing nutrients surplus, enhancing nutrient use efficiency. We also, concluded that NPs are crucial in alleviating abiotic stress and heavy metal toxicity. However, some studies reported the toxic effects of NPs on higher plants by induction of oxidative stress signals via depositing NPs on the cell surface and in organelles. The knowledge in our review article is critical in defining limitations and future perspectives of using nano-fertilizers as an alternative to conventional fertilizers.  相似文献   
288.
289.
Emergence of multidrug resistant bacteria has made the search for novel bioactive compounds from natural and unexplored habitats a necessity. Actinobacteria have important bioactive substances. The present study investigated antimicrobial activity of Actinobacteria isolated from soil samples of Egypt. One hundred samples were collected from agricultural farming soil of different governorates. Twelve isolates have produced activity against the tested microorganisms (S. aureus, Bacillus cereus, E. coli, K. pneumoniae, P. aeruginosa, S. Typhi, C. albicans, A. niger and A. flavus). By VITEK 2 system version: 07.01 the 12 isolates were identified as Kocuria kristinae, Kocuria rosea, Streptomyces griseus, Streptomyces flaveolus and Actinobacteria. Using ethyl acetate extraction method the isolates culture’s supernatants were tested by diffusion method against indicator microorganisms. These results indicate that Actinobacteria isolated from Egypt farms could be sources of antimicrobial bioactive substances.  相似文献   
290.
Information on the genetic diversity of wild rice species in Sri Lanka is relatively meagre, though it plays a key role in crop improvement programs of cultivated rice (Oryza sativa L.). The present study was carried out to identify the morphological variation pattern of the wild populations of O. nivara in Sri Lanka. Seven populations (P1 to P7) collected from different agro-ecological regions were characterized in a common garden based on nine morphological traits. The findings revealed a high level of phenotypic variation between populations when compared to within a population. The most variable traits were the flag leaf panicle neck length (FLPNL) and flag leaf angle (FLA), whereas the least variable trait was the flag leaf length (FLL). Box plots clearly illustrated the large differentiation of phenotypic traits in the entire distribution of wild rice populations. The cumulative values of the two principal components, i.e., FLPNL and FLA, explained 58.7% of the total variance. Populations from similar natural habitats clustered together. The P7 was adapted to intercept more sunlight by increasing flag leaf width (FLW) and FLA to compete with weeds and other shrubs. P2 and P5 were the most closely related populations representing approximately similar ecological conditions of the dry zone. The P3 population from the intermediate zone showed a vigorous plant growth with the highest plant height, culm girth and awn length (P < 0.05). Knowledge of such morphological diversity would facilitate designing conservation strategies and basic information for the proper utilization of wild resources in rice genetic improvement.  相似文献   
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