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1.
Milk is the best, complete food important for the development and nourishment of a neonate. Except for nutrients, milk contains biologically active opioid peptides derived from beta-casein, named beta-casomorphins (BCMs), which can exert effects in the gastrointestinal tract as well as in the whole body of neonates. The content of beta-casomorphins in human milk during maturation phases has not been studied so far. The aim of this study was to determine the content of beta-casomorphin-5 and -7 in human milk in different phases of lactation. A significantly higher concentration of both beta-casomorphins was found in colostrum than in mature milk. The concentration of beta-casomorphin in milk collected in the second month of lactation was similar to the level obtained in the fourth month of lactation. The content of beta-casomorphins in human milk was observed with the period of lactation. The level of opioid peptides may depend on the function of these peptides in neonate's body and may be associated with the maturation process.  相似文献   
2.
Several plant species defend themselves indirectly from herbivores by producing herbivore-induced volatile compounds that attract the natural enemies of herbivores. Here we tested the effects of elevated atmospheric CO(2) (720 micromol mol(-1)) concentration on this indirect defense, physiological properties, and constitutive and induced emissions of white cabbage (Brassica oleracea ssp. capitata, cvs Lennox and Rinda). We monitored the orientation behavior of the generalist predator Podisus maculiventris (Heteroptera: Pentatomidae) and the specialist parasitoid Cotesia plutellae (Hymenoptera: Braconidae) to plants damaged by Plutella xylostella (Lepidoptera: Plutellidae) in the Y-tube olfactometer. Elevated CO(2) levels did not affect stomatal densities but reduced specific leaf area and increased leaf thickness in cv Lennox. In addition to enhanced constitutive monoterpene emission, P. xylostella-damaged cabbages emitted homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene, sesquiterpene (E,E)-alpha-farnesene, and (Z)-3-hexenyl acetate. Growth at elevated CO(2) had no significant effect on the emissions expressed per leaf area, while minor reduction in the emission of homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene and (E,E)-alpha-farnesene was observed at elevated CO(2) in one of two experiments. The generalist predator P. maculiventris discriminated only between the odors of intact and P. xylostella-damaged cv Rinda plants grown at ambient CO(2) concentration, preferring the odor of the damaged plants. The specialist parasitoid C. plutellae preferred the odor of damaged plants of both cultivars grown at ambient CO(2) but did not detect damaged cv Lennox plants grown at elevated CO(2). The results suggest that elevated atmospheric CO(2) concentration could weaken the plant response induced by insect herbivore feeding and thereby lead to a disturbance of signaling to the third trophic level.  相似文献   
3.
Genetic variations in xenobiotic metabolizing genes can influence susceptibility to many environmentally induced cancers. Inheritance of the N-acetyltransferase 1 allele (NAT1*10), linked with increased metabolic activation of pro-carcinogens, is associated with an increased susceptibility to many cancers in which cigarette- or meat-derived carcinogens have been implicated in their etiology. The role of NAT1*10 in prostate cancer is under studied. Although cigarette smoking is not considered a risk factor for prostate cancer, a recent review suggests it may play a role in disease progression. Consequently, we examined the association of NAT1*10 with prostate cancer risk, grade, and stage among 400 Finnish male smokers using a case-control study design. Following genotyping of 206 patients and 196 healthy controls, our results do not support the role of NAT1*10 in relation to prostate cancer risk (OR?=?1.28; 95% CI, 0.66-2.47), aggressive disease (OR?=?0.58; 95% CI, 0.13-2.67), or advanced disease (OR?=?1.19; 95% CI, 0.49-2.91).  相似文献   
4.
5.
    
The crystal structure of aclacinomycin oxidoreductase (AknOx), a tailoring enzyme involved in the biosynthesis of the polyketide antibiotic aclacinomycin, was determined to 1.65 Å resolution by multiwavelength anomalous diffraction using data from selenomethionine‐substituted crystals. The crystals belong to space group P21, with unit‐cell parameters a = 68.2, b = 264.5, c = 68.2 Å, β = 119°. Analysis of the intensity statistics clearly showed the presence of pseudomerohedral twinning. The data set could also be indexed and scaled with an Rsym of 0.072 in the orthorhombic space group C2221 (unit‐cell parameters a = 69.7, b = 117.5, c = 264.4 Å), indicating the possibility of pseudomerohedral twinning along the diagonal between the monoclinic a and c directions. Refinement using this twin operator resulted in an Rfree of 24.2%. A monoclinic lattice with a = c and β close to 120° can emulate a hexagonal metric, with the possibility of a threefold twin operator along the b axis and three twin domains. Refinement assuming three‐domain twinning gave a final Rfree of 26.5%. The structure of AknOx can be thus refined with comparable Rfree values using either of the twin operators separately, suggesting the possibility that crystals of AknOx contain six twin domains generated by the twofold and threefold twin operators perpendicular to each other. Both twin operators coincide with noncrystallographic symmetry axes that may promote twinning.  相似文献   
6.

Background

α/β-hydrolase domain containing (ABHD)12 is a recently discovered serine hydrolase that acts in vivo as a lysophospholipase for lysophosphatidylserine. Dysfunctional ABHD12 has been linked to the rare neurodegenerative disorder called PHARC (polyneuropathy, hearing loss, ataxia, retinosis pigmentosa, cataract). In vitro, ABHD12 has been implicated in the metabolism of the endocannabinoid 2-arachidonoylglycerol (2-AG). Further studies on ABHD12 function are hampered as no selective inhibitor have been identified to date. In contrast to the situation with the other endocannabinoid hydrolases, ABHD12 has remained a challenging target for inhibitor development as no crystal structures are available to facilitate drug design.

Methodology/Principal Findings

Here we report the unexpected discovery that certain triterpene-based structures inhibit human ABHD12 hydrolase activity in a reversible manner, the best compounds showing submicromolar potency. Based on structure activity relationship (SAR) data collected for 68 natural and synthetic triterpenoid structures, a pharmacophore model has been constructed. A pentacyclic triterpene backbone with carboxyl group at position 17, small hydrophobic substituent at the position 4, hydrogen bond donor or acceptor at position 3 accompanied with four axial methyl substituents was found crucial for ABHD12 inhibitor activity. Although the triterpenoids typically may have multiple protein targets, we witnessed unprecedented selectivity for ABHD12 among the metabolic serine hydrolases, as activity-based protein profiling of mouse brain membrane proteome indicated that the representative ABHD12 inhibitors did not inhibit other serine hydrolases, nor did they target cannabinoid receptors.

Conclusions/Significance

We have identified reversibly-acting triterpene-based inhibitors that show remarkable selectivity for ABHD12 over other metabolic serine hydrolases. Based on SAR data, we have constructed the first pharmacophore model of ABHD12 inhibitors. This model should pave the way for further discovery of novel lead structures for ABHD12 selective inhibitors.  相似文献   
7.
Boreal and subarctic peatlands have been extensively studied for their major role in the global carbon balance. However, study efforts have so far neglected the contribution of these ecosystems to the non-methane biogenic volatile organic compound (BVOC) emissions, which are important in the atmospheric chemistry and feedbacks on climate change. We aimed at estimating the BVOC emissions from a subarctic peatland in northern Finland. Furthermore, our aim was to assess how these emissions are affected by enhanced UV-B radiation, the amount of which has increased especially at high latitudes as a result of stratospheric ozone depletion. The contribution of BVOC emissions to the total net carbon exchange and correlations between the emission of different BVOCs and net ecosystem CO2 exchange, CH4 emission, total green leaf area, and abiotic factors were also studied. The UV-B exposure, simulating a 20% depletion of stratospheric ozone, was started in 2003, and measurements were performed during the growing seasons of 2006 and 2008. The subarctic peatland proved to be a small source of BVOCs and the dominant moss, Warnstorfia exannulata, emitted a diverse compound spectrum. The water table level exerted a major influence on the BVOC emissions surpassing the effect of enhanced UV-B. In fact, no overall UV-B effect was established on the BVOC emissions, apart from toluene and 1-octene, emissions of which were doubled and tripled by enhanced UV-B in 2008, respectively. The contribution of BVOCs to the total net carbon exchange was below 1%.  相似文献   
8.
Summary This study describes Finnish university students' knowledge and attitudes towards HIV and AIDS, homosexuality and sexual risk behaviour. Finnish-speaking students were randomly selected from all registered students at two universities in Finland (N=9715, n=950). The data were collected by using a modified version of the State University of New York at Buffalo School of Nursing AIDS Study Questionnaire on sexual risk behaviour developed by Held and Chng. The total response rate was 35% (n=333). The data were analysed using quantitative statistical methods. Normally distributed data were analysed by t-test and one-way ANOVA, with Bonferroni corrections. Non-normally distributed data were analysed using the Mann-Whitney U-test and Kruskal-Wallis test, followed by a post-hoc test. The majority of students were familiar with HIV and AIDS, including its mode of transmission. However, there were still some misconceptions concerning HIV and AIDS. The oldest students and women had a more positive attitude towards people living with HIV and AIDS (PLWHA). Of patients with HIV or AIDS, intravenous drug users were perceived most negatively. Male students had more homophobic attitudes. Students who reported that religion had an important role in their lives had significantly stricter attitudes towards sexual risk behaviour. Students' knowledge correlated positively with general attitudes towards HIV and AIDS. Knowledge about HIV and AIDS will lead to more positive attitudes towards HIV and AIDS as a disease, towards those infected as well as homosexual people. There is a need to focus on preventive health care and sexual health promotion by educating young people and changing their attitudes towards sexual risk behaviour.  相似文献   
9.
Cirsium rivulare is a perennial plant that forms patches consisting of ramets resulting from sexual reproduction by seeds and asexual propagation by rhizome fragmentation. We examined the relationship between the size of patches and genetic differentiation of ramets within and between patches. Ramet genotypes were identified using microsatellites. From among 216 ramets examined in the studied population, 123 had a unique genotype, while 93 were clonal, i.e., their genotype was present in at least two ramets. The frequency of ramets with clonal genotypes was 43% and the frequency of unique genotypes was 57%. Ramets with identical genotypes were dominant in small patches. Large patches consisted of ramets with both unique and clonal genotypes, usually with the predominance of the latter. A molecular variance analysis showed the highest level of variance between ramets and the lowest between patches. Additionally, 21.02% of the total variance was recorded between ramets and within patches. The size of patches was correlated with the number of clonal ramets and the number of unique ramets, but it was not correlated with the clonality index. This population of C. rivulare is currently in a phase of decline from 30 years of vegetation transformation, and there appears to have been an increase in sexual propagation based growth over clonal propagation based growth. Hence, a predominance of ramets with unique genotypes was observed. This can happen as a result of disintegration of large patches and formation of gaps between them. These gaps become convenient places for seed germination and the subsequent development of seedlings.  相似文献   
10.
    
When plants are damaged by herbivorous insects they emit a blend of volatile organic compounds (VOCs) which include a range or terpenoids and green leaf volatiles (GLVs) formed via different metabolic pathways. The precise timing of these emissions upon the onset of herbivore feeding has not been fully elucidated, and the information that is available has been mainly obtained through laboratory based studies. We investigated emissions of VOCs from Populus tremula L. ×P. tremuloides Michx. during the first 20 h of feeding by Epirrita autumnata (autumnal moth) larvae in a field site. The study was conducted using Proton Transfer Reaction‐Mass Spectrometry (PTR‐MS) to measure emissions online, with samples collected for subsequent analysis by complementary gas chromatography‐mass spectrometry for purposes of compound identification. GLV emission peaks occurred sporadically from the outset, indicating herbivore activity, while terpene emissions were induced within 16 h. We present data detailing the patterns of monoterpene (MT), GLV and sesquiterpene (SQT) emissions during the early stages of herbivore feeding showing diurnal MT and SQT emission that is correlated more with temperature than light. Peculiarities in the timing of SQT emissions prompted us to conduct a thorough characterization of the equipment used to collect VOCs and thus corroborate the accuracy of results. A laboratory based analysis of the throughput of known GLV, MT and SQT standards at different temperatures was made with PTR‐MS. Enclosure temperatures of 12, 20 and 25°C had little influence on the response time for dynamic measurements of a GLV or MT. However, there was a clear effect on SQT measurements. Elucidation of emission patterns in real‐time is dependent upon the dynamics of cuvettes at different temperatures.  相似文献   
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