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排序方式: 共有151条查询结果,搜索用时 15 毫秒
1.
Jan Christian Habel Marc Meyer Abdelhamid El Mousadik Thomas Schmitt 《Organisms Diversity & Evolution》2008,8(2):121-129
Climatic oscillations influence the distribution of species in time. Thermophilic species survived the ice ages in refugia around the Mediterranean. Northern Africa is one of the possibly important refugia. In this study we test the genetic differentiation between northern African and European populations, using the marbled white butterfly species complex, Melanargia galathea/M. lachesis, as a model. We studied 18 allozyme loci in 876 individuals from 23 populations representing a major part of Europe (northern Spain to Romania) and the western part of northern Africa (Atlas Mountains). The African populations resemble the European ones in allelic richness; their genetic diversity is higher than in Europe. Cluster analysis discriminated five European genetic groups: M. lachesis, a western European lineage, and three eastern European lineages. However, the African samples did not form a separate cluster within this phenogram, but clustered randomly within the Balkan/southeastern European groups. The genetic differentiation among the African populations (FST 8.8%) was higher than that within any of the European lineages (FST 2.6–5.5%). The high genetic diversity and the relatively strong differentiation of the four African populations sampled in a comparatively limited area of the Atlas Mountains indicate that the most probable origin of M. galathea is northern Africa, with its sibling species, M. lachesis, evolving in parallel in Iberia. Most probably, M. galathea colonised Europe first during the Eem interglacial, some 130 ky ago. Since M. lachesis must have existed on the Iberian peninsula during that period already, M. galathea should have reached Europe via Italy. The genetic differentiation to distinct groups in Europe most probably evolved during the following Würm glacial period. 相似文献
2.
Lawren VandeVrede Ramy Abdelhamid Zhihui Qin Jaewoo Choi Sujeewa Piyankarage Jia Luo John Larson Brian M. Bennett Gregory R. J. Thatcher 《PloS one》2013,8(8)
Selective estrogen receptor modulators (SERMs) are effective therapeutics that preserve favorable actions of estrogens on bone and act as antiestrogens in breast tissue, decreasing the risk of vertebral fractures and breast cancer, but their potential in neuroprotective and procognitive therapy is limited by: 1) an increased lifetime risk of thrombotic events; and 2) an attenuated response to estrogens with age, sometimes linked to endothelial nitric oxide synthase (eNOS) dysfunction. Herein, three 3rd generation SERMs with similar high affinity for estrogen receptors (ERα, ERβ) were studied: desmethylarzoxifene (DMA), FDMA, and a novel NO-donating SERM (NO-DMA). Neuroprotection was studied in primary rat neurons exposed to oxygen glucose deprivation; reversal of cholinergic cognitive deficit was studied in mice in a behavioral model of memory; long term potentiation (LTP), underlying cognition, was measured in hippocampal slices from older 3×Tg Alzheimer''s transgenic mice; vasodilation was measured in rat aortic strips; and anticoagulant activity was compared. Pharmacologic blockade of GPR30 and NOS; denudation of endothelium; measurement of NO; and genetic knockout of eNOS were used to probe mechanism. Comparison of the three chemical probes indicates key roles for GPR30 and eNOS in mediating therapeutic activity. Procognitive, vasodilator and anticoagulant activities of DMA were found to be eNOS dependent, while neuroprotection and restoration of LTP were both shown to be dependent upon GPR30, a G-protein coupled receptor mediating estrogenic function. Finally, the observation that an NO-SERM shows enhanced vasodilation and anticoagulant activity, while retaining the positive attributes of SERMs even in the presence of NOS dysfunction, indicates a potential therapeutic approach without the increased risk of thrombotic events. 相似文献
3.
Majida Charif Amina Bakhchane Omar Abidi Redouane Boulouiz Abdelmajid Eloualid Rachida Roky Hassan Rouba Mostafa Kandil Guy Lenaers Abdelhamid Barakat 《Gene》2013
Mutations in the CLDN14 gene, encoding the tight junction claudin 14 protein has been reported to date in an autosomal recessive form of isolated hearing loss DFNB29. In order to identify the contribution of CLDN14 to inherited deafness in Moroccan population, we performed a genetic analysis of this gene in 80 Moroccan familial cases. Our results show the presence of 7 mutations: 6 being conservative and one leading to a missense mutation (C11T) which was found at heterozygous and homozygous states, with a general frequency of 6.87%. The pathogenicity of the resulting T4M substitution is under discussion. 相似文献
4.
S Lewicka P Vecsei K Bige T Fisher J Winter S Abdelhamid U Heinrich V D Bokkenheuser 《Journal of steroid biochemistry》1988,29(3):333-339
Using tetrahydroaldosterone antibody a radioimmunoassay was developed to measure substance Kelly-M1 (K-M1) in human urine. The normal values were lower than observed by Kelly et al. who discovered the catabolite after giving large doses of exogenous aldosterone. While in essential hypertension the excretion of K-M1 was predominantly within the normal range, elevated values were found in most cases of 21-hydroxylase deficiency, both the simple virilizing and salt losing form, primary aldosteronism, renal hypertension and cystinosis. Our findings suggest that K-M1 may be formed from 21-deoxyaldosterone and/or by microbial intervention from aldosterone or its metabolites. 相似文献
5.
Influence of age,castration, and testosterone on T cell subsets in healthy and leukemia grafted mice 总被引:1,自引:0,他引:1
Aboudkhil S Zaîd A Henry L Bureau JP 《Biology of the cell / under the auspices of the European Cell Biology Organization》2003,95(1):9-16
The distribution of T cell subsets in pubertal (2 months) and post-pubertal (10 months) mice showed a significant decrease in the percentage of CD4+ splenocytes and peripheral blood lymphocytes (PBL) with age, unlike the percentage of CD8+ cells in PBL, which remained unchanged. The change in the distribution of T cell subsets in the spleen and blood occurred in 2 months old castrated mice, as in 10 months old animals. P388 tumor grew better in post-pubertal and in castrated mice than in young mice. The intact mice survived longer than the castrated ones. The relative number of CD4+, CD8+ and CD2+ splenocytes was lower in transplanted intact mice than that in controls. The CD8+ and CD2+ subsets in the blood of 2 months transplanted mice were higher than those in controls, whereas in PBL, in 10 months old and castrated mice, the T lymphocyte subsets remain unchanged. Depo-testosterone (DT) injection strongly reduced weight and tumor growth in all the intact and castrated animals. A significant correlation is observed between the tumor weight and testosterone level in the plasma of the 2 months old DT treated mice. Moreover, DT injection induced a significant increase in the percentage of blood CD8+ cells in all the batches. These data indicate that physiologically, androgens affect the age-related distribution of lymphocyte T subsets and suggest that they slow down tumor growth, besides causing a direct effect, through an immunological process. 相似文献
6.
7.
Khaoula Rochdi Cerino Mathieu Da Silva Nathalie Delague Valerie Nahili Halima Kriouile Yamna Gorokhova Svetlana Bartoli Marc Saïle Rachid Barakat Abdelhamid Krahn Martin 《Molecular biology reports》2021,48(10):6999-7006
Molecular Biology Reports - Congenital myasthenic syndromes (CMS) are associated with defects in the structure and the function of neuromuscular junctions. These rare disorders can result from... 相似文献
8.
The effect of NAD(P) and analogs of this nucleotide on nitrogenase activity in Rhodospirillum rubrum has been studied. Addition of NAD+ to nitrogen fixing Rsp. rubrum leads to inhibition of nitrogenase. NADP+ has the same effect but NADH or analogs modified in the nicotinamide portion do not cause inhibition. In contrast to ammonium
ions, addition of NAD+ leads to inhibition of nitrogenase in cells that have been N-starved under argon. The inhibitory effect of NAD+ is more pronounced at lower light intensities. Addition of NAD+ also leads to inhibition of glutamine synthetase, a phenomenon also occurring when “switchoff” is produced by the addition
of effectors such as ammonium ions or glutamine. It is also shown that NAD+ is taken up by Rsp. rubrum cells. 相似文献
9.
Involvement of Cd Bioaccumulation in Spinal Deformities Occurrence in Natural Populations of Mediterranean Killifish 总被引:1,自引:0,他引:1
The aim of this study was to investigate the possible influence of environmental exposure to cadmium (Cd) on the spinal deformities
occurrence in the Mediterranean killifish, Aphanius fasciatus (Pisces: Cyprinodontidae). For this purpose, some indicators of skeletal bone mineralization, Cd, and calcium (Ca) concentrations
in spinal column as well as bioaccumulation of Cd from the water and the sediment have been compared in normal and deformed
fish collected from polluted (S1) and nonpolluted (S2) areas in the Gulf of Gabès in Tunisia. When compared to the normal
fish, the deformed fish showed signs of spinal column demineralization such as significant decrease in the ash weight/dry
weight ratio, percentage of nonorganic components content, and Ca concentration. Cd concentrations in spinal column and liver
were significantly higher in deformed fish than in normal fish. A highly significant negative correlation (r = −0.915, p < 0.01) between Cd and Ca concentrations was noted in spinal column of deformed fish. Bioaccumulation factors of Cd in the
liver from the water and the sediment in deformed fish were also significantly higher (p < 0.0001) than in normal fish from S1 and S2. These findings suggest that the ability to accumulate large amount of Cd may
represent a potential risk to induce spinal deformities in natural populations of Mediterranean killifish. 相似文献
10.
Mariem Khouja Rita C. Alves Diana Melo Anabela S. G. Costa M. Antonia Nunes Abdelhamid Khaldi M. Beatriz P. P. Oliveira Chokri Messaoud 《化学与生物多样性》2021,18(6):e2100071
The lipid fraction of seeds from different pine species and populations was studied regarding total lipid content, fatty acid profile and vitamin E composition. The investigated seeds contained a high percentage of lipid (13.6 to 31.5 %). Lipid fractions were found to be rich in vitamin E, which varied significantly among species and populations. P. halepensis (Ph−Hn) showed the highest content of vitamin E (256.3 mg/kg of seeds) and the uppermost content of α-tocopherol (44 mg/kg). However, P. halepensis (Ph−Kas) was the richest in γ-tocopherol (204.9 mg/kg). Lipid fractions had a low content of δ-tocopherol (1.2 to 3.6 mg/kg. The highest content of γ-tocotrienol (∼18 %) was determined for P. halepensis (Ph−Dc and Ph−Hn). Thirteen fatty acids were identified by GC-FID with significant variation between the investigated species. The linoleic acid was the major fatty acid followed by oleic acid and palmitic acid. The chemical differentiation among species for the composition of fatty acids and vitamin E was confirmed by PCA. Significant correlations were observed between the content of vitamin E and fatty acids and ecological parameters of P. halepensis populations. 相似文献