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71.
W. Pauwels P. B. Farmer S. Osterman-Golkar M. Severi R. Cordero E. Bailey H. Veulemans 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,702(1-2)
A ring-test was organised between three laboratories using different versions of the modified Edman degradation technique for the gas chromatographic-mass spectrometric determination of N-terminal valine adducts of styrene 7,8-oxide. The analyses were performed on a sample of human haemoglobin reacted in vitro with styrene 7,8-oxide and on a set of five haemoglobin samples from mice dosed by i.p. injection of styrene. Strong correlations between the haemoglobin adduct determinations of the different laboratories were observed. However, covariance analysis revealed different slopes for the dose-response curves, indicating differences for the calibration of the reference globin or reference peptide. 相似文献
72.
73.
Photosynthetic responses to temperature of two tropical rainforest tree species from Costa Rica 总被引:1,自引:0,他引:1
Annual mean temperature increases will cause alterations in many ecosystem processes, which affect plants given their physiological sensitivity to temperature. That is closely related with plant growing conditions, genotype and plasticity. We studied the photosynthetic responses to instantaneous temperature changes and functional leaf traits in two tropical tree species associated with different successional positions, Zygia longifolia (early successional) and Dipteryx oleifera (late successional), in the northern lowlands of Costa Rica. We found that D. oleifera had thicker leaves and lower stomatal density, but similar specific leaf area to Z. longifolia. Maximum photosynthetic rate (A max) and maximum RuBP saturate rate of carboxylation were higher in Z. longifolia than in D. oleifera. At 37 °C, only Z. longifolia reduced A max and water use efficiency (WUE). But D. panamensis presented more severe effects on the quantum yield, respiration and light compensation points. The temperature response curves showed a similar optimum temperature near 27 °C for both species. On the other hand, the low and high temperature compensation points were different, with D. oleifera showing a narrower range than Z. longifolia. As a whole, we found two different strategies to avoid temperature stress: one reducing WUE (Z. longifolia), and the other one increasing metabolic rates (D. oleifera). However, the ability to withstand stressful situations may, in a larger context, negatively affect ecosystem water and carbon fluxes. Also, functional plasticity in response to temperature changes may relatively affect the ecosystem by causing long-term variations in their representation within the complex diversity mosaic of their forest habitats. 相似文献
74.
75.
English ivy (Hedera helix) plants were assessed for the applicability of the plastochron index (PI). Juvenile ivy satisfied all requirements for the use of the PI and showed a plastochron of 4.23 days. Mature ivy grown under long day conditions flowered after 11–12 leaves. Two distinct groups of leaves were produced with different plastochrons (0.83 and 3.2 days, respectively) and leaf morphologies. Long-day-grown ivy did not satisfy the requirements for the use of the PI. Short-day-grown mature ivy continued production of leaves beyond the 12th leaf. Vegetative growth was perpetuated for at least 25 plastochrons. By 19 plastochrons (ca. 41 days after budbreak) a linear PI vs. time relationship was established with a plastochron of 3.16 days. This newly acquired ability to maintain vegetative growth in mature ivy plants may allow a direct comparison with the vegetative indeterminant juvenile in order to assess possible anatomical factors responsible for phase stability and phase change using the PI as a basis for comparison. 相似文献
76.
77.
Juan M. Suárez-Rivero Mario de la Mata Ana Delgado Pavón Marina Villanueva-Paz Suleva Povea-Cabello David Cotán Mónica Álvarez-Córdoba Irene Villalón-García Patricia Ybot-González Joaquín J. Salas Ovidio Muñiz Mario D. Cordero José A. Sánchez-Alcázar 《生物化学与生物物理学报:疾病的分子基础》2018,1864(12):3697-3713
Familial Hypercholesterolemia (FH) is an autosomal co-dominant genetic disorder characterized by elevated low-density lipoprotein (LDL) cholesterol levels and increased risk for premature cardiovascular disease. Here, we examined FH pathophysiology in skin fibroblasts derived from FH patients harboring heterozygous mutations in the LDL-receptor.Fibroblasts from FH patients showed a reduced LDL-uptake associated with increased intracellular cholesterol levels and coenzyme Q10 (CoQ10) deficiency, suggesting dysregulation of the mevalonate pathway.Secondary CoQ10 deficiency was associated with mitochondrial depolarization and mitophagy activation in FH fibroblasts. Persistent mitophagy altered autophagy flux and induced inflammasome activation accompanied by increased production of cytokines by mutant cells. All the pathological alterations in FH fibroblasts were also reproduced in a human endothelial cell line by LDL-receptor gene silencing.Both increased intracellular cholesterol and mitochondrial dysfunction in FH fibroblasts were partially restored by CoQ10 supplementation. Dysregulated mevalonate pathway in FH, including increased expression of cholesterogenic enzymes and decreased expression of CoQ10 biosynthetic enzymes, was also corrected by CoQ10 treatment.Reduced CoQ10 content and mitochondrial dysfunction may play an important role in the pathophysiology of early atherosclerosis in FH. The diagnosis of CoQ10 deficiency and mitochondrial impairment in FH patients may also be important to establish early treatment with CoQ10. 相似文献
78.
Myogenic Differentiation Potential of Mesenchymal Stem Cells Derived from Fetal Bovine Bone Marrow 总被引:1,自引:0,他引:1
Lucas Hidenori Okamura Paloma Cordero Jaime Palomino Victor Hugo Parraguez Cristian Gabriel Torres 《Animal biotechnology》2018,29(1):1-11
The myogenic potential of bovine fetal MSC (bfMSC) derived from bone marrow (BM) remains unknown; despite its potential application for the study of myogenesis and its implications for livestock production. In the present study, three protocols for in vitro myogenic differentiation of bfMSC based on the use of DNA methyltransferase inhibitor 5-Aza-2′-deoxycytidine (5-Aza), myoblast-secreted factor Galectin-1 (Gal-1), and myoblast culture medium SkGM-2 BulletKit were used. Plastic-adherent bfMSC were isolated from fetal BM collected from abattoir-derived fetuses. Post-thaw viability analyses detected 85.6% bfMSC negative for propidium iodine (PI). Levels of muscle regulatory factors (MRF) MYF5, MYF6, MYOD, and DES mRNA were higher (P?0.05) in bfMSC cultured under 100?µM of 5-Aza compared to 1 and 10?µM. Treatment of bfMSC with 10?µM of 5-Aza resulted in down-regulation of MYOD mRNA (Days 7 to 21) and up-regulation of MYF6 (Day 7), MYF5, and DES mRNA (Day 21). Gal-1 and SkGM-2 BulletKit induced sequential down-regulation of early MRF (MYF5) and up-regulation of intermediate (MYOD) and late MRF (DES) mRNA. Moreover, DES and MYF5 were immunodetected in differentiated bfMSC. In conclusion, protocols evaluated in bfMSC induced progress into myogenic differentiation until certain extent evidenced by changes in MRF gene expression. 相似文献
79.
Maren Wellenreuther Jesús Muñoz Jesús R. Chávez‐Ríos Bengt Hansson Adolfo Cordero‐Rivera Rosa A. Sánchez‐Guillén 《Ecology and evolution》2018,8(10):4793-4806
Many species are currently changing their distributions and subsequently form sympatric zones with hybridization between formerly allopatric species as one possible consequence. The damselfly Ischnura elegans has recently expanded south into the range of its ecologically and morphologically similar sister species Ischnura graellsii. Molecular work shows ongoing introgression between these species, but the extent to which this species mixing is modulated by ecological niche use is not known. Here, we (1) conduct a detailed population genetic analysis based on molecular markers and (2) model the ecological niche use of both species in allopatric and sympatric regions. Population genetic analyses showed chronic introgression between I. elegans and I. graellsii across a wide part of Spain, and admixture analysis corroborated this, showing that the majority of I. elegans from the sympatric zone could not be assigned to either the I. elegans or I. graellsii species cluster. Niche modeling demonstrated that I. elegans has modified its environmental niche following hybridization and genetic introgression with I. graellsii, making niche space of introgressed I. elegans populations more similar to I. graellsii. Taken together, this corroborates the view that adaptive introgression has moved genes from I. graellsii into I. elegans and that this process is enabling Spanish I. elegans to occupy a novel niche, further facilitating its expansion. Our results add to the growing evidence that hybridization can play an important and creative role in the adaptive evolution of animals. 相似文献
80.
The yeast Yarrowia lipolytica was shown to be sensitive to the aminoglycoside antibiotic hygromycin B. Spontaneous resistants appeared at a frequency of
(2–5)×10-7 in media containing 100 mg/l drug. In order to develop a new selective marker for the transformation of this yeast, we constructed
new plasmids expressing the Escherichia coli hygromycin-resistance gene (hph) under the control of the promoter and terminator sequences of the strongly expressed XPR2 gene of Y. lipolytica. Direct selection of hygromycin-B-resistant transformants on complete medium was very efficient and resulted in transformation
frequencies comparable to those observed with conventional auxotrophic markers. This new marker can be used for integrating
single copies of plasmid and for gene disruption and provides a convenient tag for genetic studies.
Received: 16 February 1996/Received revision: 12 April 1996/Accepted: 15 April 1996 相似文献