全文获取类型
收费全文 | 210篇 |
免费 | 13篇 |
专业分类
223篇 |
出版年
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 16篇 |
2014年 | 16篇 |
2013年 | 14篇 |
2012年 | 21篇 |
2011年 | 27篇 |
2010年 | 12篇 |
2009年 | 8篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 8篇 |
2005年 | 12篇 |
2004年 | 10篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1986年 | 1篇 |
1982年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1967年 | 1篇 |
1963年 | 1篇 |
1961年 | 3篇 |
排序方式: 共有223条查询结果,搜索用时 15 毫秒
11.
Basic personality traits and specific behavior characteristics were assess in 39 patients (12 to 15 years old) having chronic tension-type headache. Patients were referred for clinical examination to the Neural-pediatrics Ward of the Department of Pediatrics, Osijek, Croatia. Eysenck Personality Questionnaire--Juniors (EPQ-J), a new Croatian personality Questionnaire of domination, aggression, introversion and ambition (DAIA), were applied for the testing. The scores obtained by patients in personality questionnaires were compared with averages scores normal sample of healthy pupil same ages. Our patients were found to have no signs of emotional instability. Their behavior is prosocial, nonaggressive, and ambitious, aimed at the achievement of superior results at school and life although already quite successful in their studies. Tensions arising from the school setting seem to be important factors triggering tension-type headaches. 相似文献
12.
Villi arachnoidales undergoes in the course of life changes in relation to the skull bones and sinuses. Our aim was to determine the relations of the villi arachnoidales to the skull bone and/or sinuses from the neonatal period to adults. The investigations were performed on collection of 50 disarticulated macerated skull bones from the new-born to 30 years of age and on 20 skulls from individuals in the life period from 30 to 80 years of age. Villi arachnoidales produced imprints on the skull bones in the shape of holes and/or furrows corresponding to different shape of the villi arachnoidales. These imprints appeared very early in the period when the bony sprouts of the large skull bones received a thin covering of compact bone, the future lamina vitrea. At that time villi arachnoidales had no connection with the dural sinuses but with the diploe and with the diploic veins. By agglomeration of the villi in larger and large formations, granula meningea, Pacchionian granulations, the contact to sinuses was realized by means of short channels. The structural changes of villi arachnoidales may produce thrombophlebitis and hydrocephalus externus, especially in children. The fate and the relations of the villi arachnoidales are therefore of great importance for neurologist, neurosurgeon and otorhinolaryngologist. 相似文献
13.
Ilijin L Janković-Tomanić M Mitić M Vlahović M Lazarević J Perić-Maratuga V Prolić Z Nenadović V 《Folia biologica》2003,51(3-4):207-211
The response of Morimus funereus larvae to total starvation and refeeding with qualitatively different nutritive substrates (artificial diets supplemented with yeast as a source of B complex vitamins or with a digestibility reducer-tannic acid) was examined in this paper. Refeeding resulted in a compensatory increase of larval growth. Feeding and refeeding with qualitatively different nutritive substrates affected both quality and quantity of midgut and brain proteins. The observed differences suggest the possible switching of enzyme isoforms in M. funereus midgut and changes in synthesis/secretion of neurohormones, depending on food presence and its nutritional value. 相似文献
14.
Prolonged immobilization results in several physiological problems. It has been demonstrated that standing exercises can ameliorate many of these problems. Standing exercises can be performed efficiently with the help of functional electrical stimulation (FES). A novel robotic mechanism which aids the unsupported standing of paraplegics, providing balancing exercise has been developed. The balancing strategy is based on voluntary activity of the paraplegic's upper body and artificially controlled stiffness in the ankles. 相似文献
15.
Java editor for biological pathways 总被引:1,自引:0,他引:1
SUMMARY: A visual Java-based tool for drawing and annotating biological pathways was developed. This tool integrates the possibilities of charting elements with different attributes (size, color, labels), drawing connections between elements in distinct characteristics (color, structure, width, arrows), as well as adding links to molecular biology databases, promoter sequences, information on the function of the genes or gene products, and references. It is easy to use and system independent. The result of the editing process is a PNG (portable network graphics) file for the images and XML (extended markup language) file for the appropriate links. 相似文献
16.
Sturn A Mlecnik B Pieler R Rainer J Truskaller T Trajanoski Z 《Bioinformatics (Oxford, England)》2003,19(6):772-773
SUMMARY: We have developed a platform independent, flexible and scalable Java environment for high-performance large-scale gene expression data analysis, which integrates various computational intensive hierarchical and non-hierarchical clustering algorithms. The environment includes a powerful client for data preparation and results visualization, an application server for computation and an additional administration tool. The package is available free of charge for academic and non-profit institutions. 相似文献
17.
The effect of substances with different redox potentials in the phytochrome-controlled germination of Paulmtnia tomentosa seeds was examined. Up to 25% of water-imbibed seeds germinated upon irradiation with 5 min red light The seeds irradiated with 5 min red light and incubated in substances with redox potentials equal or higher than E'0 = 360 mV [potassium nitrate, potassium hexacyanoferrate (III) or potassium hexachloroiridate (IV)] and sodium nitroprusside germinated up to 80%. The optimal concentration was between 1 and 10 mM. Other electron acceptors such as 2.6-dichlorophenol-indoplhenol, phenazine methosulfate and methylene blue failed to produce and effect. The germination-promoting effect was obtained when the substances were supplied to the incubation medium from the onset of imbibition or at the onset of irradiation. Delay of application of these chemicals until after the red light treatment diminished their effectiveness and the effect was lost after 48 h. The escape from far-red reversibility was evident in the presence of substances which stimulated germination. The results presented support the view that phytochrome-broken dormancy of Paulownia tomentosa seeds is closely connected with redox changes. 相似文献
18.
Zlatko Petrin Emily G. Schilling Cynthia S. Loftin Frank Johansson 《Evolutionary ecology》2010,24(5):1003-1016
Predators strongly influence species assemblages and shape morphological defenses of prey. Interestingly, adaptations that
constitute effective defenses against one type of predator may render the prey susceptible to other types of predators. Hence,
prey may evolve different strategies to escape predation, which may facilitate adaptive radiation of prey organisms. Larvae
of different species in the dragonfly genus Leucorrhinia have various morphological defenses. We studied the distribution of these larvae in relation to the presence of predatory
fish. In addition, we examined the variation in morphological defenses within species with respect to the occurrence of fish.
We found that well-defended species, those with more and longer spines, were more closely associated with habitats inhabited
by predatory fish and that species with weakly developed morphological defenses were more abundant in habitats without fish.
The species predominantly connected to lakes with or without fish, respectively, were not restricted to a single clade in
the phylogeny of the genus. Our data is suggestive of phenotypic plasticity in morphological defense in three of the studied
species since these species showed longer spines in lakes with fish. We suggest that adaptive phenotypic plasticity may have
broadened the range of habitats accessible to Leucorrhinia. It may have facilitated colonization of new habitats with different types of predators, and ultimately, speciation through
adaptive radiation. 相似文献
19.
The purpose of this study was to characterize biomechanically three different crouch walking patterns, artificially induced in eight neurologically intact subjects and to compare them to selected cases of pathological crouch walking. The subjects were equipped with a lightweight mechanical exoskeleton with artificial muscles that acted in parallel with hamstrings and iliopsoas muscles. They walked at a speed of approximately 1m/s along the walkway under four experimental conditions: normal walking (NW), hamstrings contracture emulation (HAM), iliopsoas contracture emulation (IPS) and emulation of both hamstrings and iliopsoas contractures (IPSHAM). Reflective markers and force platform data were collected and ankle, knee and hip-joint angles, moments and powers were calculated. HAM and IPSHAM shifted ankle-angle rotation profiles into dorsiflexion during midstance compared to IPS and NW where ankle-angle trajectories were similar. HAM, IPS and IPSHAM shifted the knee angle of rotation profiles into flexion during stance, compared to NW. IPS and IPSHAM shifted hip angle of rotation profiles toward pronounced flexion while HAM shifted hip angle of rotation profile toward extension, compared to NW. HAM and IPSHAM significantly increased ankle moment during midstance, compared to IPS and NW where ankle moment profiles were similar. All experimental conditions exhibited similar behavior in the knee-moment profiles during midstance while IPS and IPSHAM knee-moment profiles exhibited significantly higher knee-extension moment during terminal stance and pre-swing. In the hip joint all experimental conditions exhibited similar shape of hip moment profiles throughout the gait cycle. HAM and IPS kinematic and kinetic patterns were qualitatively compared to two selected clinical cases, showing considerable similarity. This implies that distinct differences in kinematics and kinetics between HAM, IPS and IPSHAM may be clinically relevant in helping determine the relative contribution of hamstrings and iliopsoas muscles contractures to particular crouch walking. 相似文献
20.
Weiwei Wen Kun Li Saleh Alseekh Nooshin Omranian Lijun Zhao Yang Zhou Yingjie Xiao Min Jin Ning Yang Haijun Liu Alexandra Florian Wenqiang Li Qingchun Pan Zoran Nikoloski Jianbing Yan Alisdair R. Fernie 《The Plant cell》2015,27(7):1839-1856
Deciphering the influence of genetics on primary metabolism in plants will provide insights useful for genetic improvement and enhance our fundamental understanding of plant growth and development. Although maize (Zea mays) is a major crop for food and feed worldwide, the genetic architecture of its primary metabolism is largely unknown. Here, we use high-density linkage mapping to dissect large-scale metabolic traits measured in three different tissues (leaf at seedling stage, leaf at reproductive stage, and kernel at 15 d after pollination [DAP]) of a maize recombinant inbred line population. We identify 297 quantitative trait loci (QTLs) with moderate (86.2% of the mapped QTL, R2 = 2.4 to 15%) to major effects (13.8% of the mapped QTL, R2 >15%) for 79 primary metabolites across three tissues. Pairwise epistatic interactions between these identified loci are detected for more than 25.9% metabolites explaining 6.6% of the phenotypic variance on average (ranging between 1.7 and 16.6%), which implies that epistasis may play an important role for some metabolites. Key candidate genes are highlighted and mapped to carbohydrate metabolism, the tricarboxylic acid cycle, and several important amino acid biosynthetic and catabolic pathways, with two of them being further validated using candidate gene association and expression profiling analysis. Our results reveal a metabolite-metabolite-agronomic trait network that, together with the genetic determinants of maize primary metabolism identified herein, promotes efficient utilization of metabolites in maize improvement. 相似文献