全文获取类型
收费全文 | 227篇 |
免费 | 11篇 |
出版年
2023年 | 1篇 |
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 11篇 |
2013年 | 13篇 |
2012年 | 27篇 |
2011年 | 14篇 |
2010年 | 11篇 |
2009年 | 13篇 |
2008年 | 14篇 |
2007年 | 16篇 |
2006年 | 13篇 |
2005年 | 8篇 |
2004年 | 11篇 |
2003年 | 15篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有238条查询结果,搜索用时 31 毫秒
81.
Spasic S Culic M Grbic G Martac L Sekulic S Mutavdzic D 《Bulletin of mathematical biology》2008,70(4):1235-1249
The cerebellum, even when not directly damaged, is potentially interesting for understanding the adaptive responses to brain
injury. Cerebellar electrocortical activity (ECoG) in rats was studied using spectral and fractal analysis after single and
repeated unilateral injury of the parietal cortex. Local field potentials of cerebellar paravermal cortex were recorded before
brain injury, in the acute phase (up to 2.5 hours) after a first injury of anesthetized rats, and then before and after second,
third, and, in some cases, fourth injury. Relative gamma power (32.1–128.0 Hz) and fractal dimension of ECoGs were temporarily
increased after the first injury. However, there was a permanent mild increase in gamma activity and a mild increase in the
fractal dimension of cerebellar activity as a chronic change after repeated remote brain injury. There was a negative linear
correlation between the normalized difference in fractal dimensions and normalized difference in gamma powers of cerebellar
activity only in the case of repeated brain injury. This is the first study showing that correlation between the parameters
of spectral and fractal analyses of cerebellar activity can discriminate between single and repeated brain injuries, and is,
therefore, a promising approach for identifying specific pathophysiological states. 相似文献
82.
Dragana Stanojević Ljiljana Čomić Olgica Stefanović 《Central European Journal of Biology》2010,5(4):491-495
The aim of the present study is to investigate the antibacterial activity of Salvia officinalis L. aqueous extracts and its synergistic action with preservatives sodium nitrite, sodium benzoate and potassium sorbate in vitro against selected food spoiling bacteria. Synergy was assessed by the checkerboard assay method and quantitatively represented
by the FIC index. Synergistic action was established for aqueous extract/ sodium benzoate, aqueous extract/ potassium sorbate,
aqueous extract/ sodium nitrite combinations. Synergy was detected in relation to: Agrobacterium tumefaciens, Bacillus subtilis and Proteus sp. Synergy was established at plant extract and preservative concentrations corresponding up to 1/8 MIC values. 相似文献
83.
84.
85.
Effects of sex, age, body mass, and capturing method on hematologic values of brown bears in Croatia
Kusak J Rafaj RB Zvorc Z Huber D Forsek J Bedrica L Mrljak V 《Journal of wildlife diseases》2005,41(4):843-847
Effects of various intrinsic and extrinsic factors on 17 hematologic values from 56 brown bears (Ursus arctos) sampled in Croatia from 1981 to 2005 were evaluated. Differences between female and male bears were detected for number of erythrocytes, sedimentation rate after 30 min, and number of leukocytes and segmented neutrophils. Significant differences between free-living vs. captive and snared vs. not snared bears were detected for the same three parameters: leukocytes, segmented neutrophils, and eosinophils. It was concluded that the physical exertion of bears snared by leg, rather than their free-living status, influenced differences of results among these groups. The obtained mean values are useful reference values for the species. 相似文献
86.
Serman L Serman A Lauc G Milić A Latin V Aleksandrova A Serman D 《Collegium antropologicum》2004,28(1):301-308
Contemporary understanding of missed abortion, as the case of spontaneous abortion where embryo is retained in uterus for four-weeks or more after its death, is very poor. Aiming to improve the level of knowledge about this process, we have compared glycosylation patterns of placental proteins in normal pregnancy and missed abortion. Oligosaccharide branches were detected by Western-blot using SNA, DBA and PHA-E lectins. The comparison of samples of the same gestational age enabled identification of changes in protein glycosylation between normal and pathological placentas. Lectin DBA detects in normal placenta the glycoprotein GP 105 during the eleventh week, which is absent in missed abortion. PHA-E identifies GP 71 during fourteenth week only in normal placenta. However GP 25 recognized by SNA in missed abortion was not found in normal pregnancy at tenth week. These results indicate that abnormal placental development is associated with changes in glycoprotein structures, and that glycoconjugates might have an important role in placental development. 相似文献
87.
Cell-autonomous death of cerebellar purkinje neurons with autophagy in Niemann-Pick type C disease 总被引:1,自引:0,他引:1
Niemann-Pick type C is a neurodegenerative lysosomal storage disorder caused by mutations in either of two genes, npc1 and npc2. Cells lacking Npc1, which is a transmembrane protein related to the Hedgehog receptor Patched, or Npc2, which is a secreted cholesterol-binding protein, have aberrant organelle trafficking and accumulate large quantities of cholesterol and other lipids. Though the Npc proteins are produced by all cells, cerebellar Purkinje neurons are especially sensitive to loss of Npc function. Since Niemann-Pick type C disease involves circulating molecules such as sterols and steroids and a robust inflammatory response within the brain parenchyma, it is crucial to determine whether external factors affect the survival of Purkinje cells (PCs). We investigated the basis of neurodegeneration in chimeric mice that have functional npc1 in only some cells. Death of mutant npc1 cells was not prevented by neighboring wild-type cells, and wild-type PCs were not poisoned by surrounding mutant npc1 cells. PCs undergoing cell-autonomous degeneration have features consistent with autophagic cell death. Chimeric mice exhibited a remarkable delay and reduction of wasting and ataxia despite their substantial amount of mutant tissue and dying cells, revealing a robust mechanism that partially compensates for massive PC death. 相似文献
88.
Jovana Jasnic-Savovic Sabine Krause Slobodan Savic Ana Kojic Vlado Kovcic Srdjan Boskovic Aleksandra Nestorovic Ljiljana Rakicevic Olivia Schreiber-Katz Johannes G. Vogel Benedikt G. Schoser Maggie C. Walter Giorgio Valle Dragica Radojkovic Georgine Faulkner Snezana Kojic 《Histochemistry and cell biology》2016,146(5):569-584
89.
Fabio Bulleri Lisandro Benedetti‐Cecchi Andrej Jaklin Ljiljana Ivea 《Ecology and evolution》2016,6(7):2010-2021
Biological invasions threaten biodiversity worldwide. Nonetheless, a unified theory linking disturbance and resistance to invasion through a mechanistic understanding of the changes caused to biodiversity is elusive. Building on different forms of the disturbance‐biodiversity relationship and on the Biotic Resistance Hypothesis (BRH), we constructed conceptual models showing that, according to the main biodiversity mechanism generating invasion resistance (complementary vs. identity effects), disturbance can either promote or hinder invasion. Following the Intermediate Disturbance Hypothesis (IDH), moderate levels of disturbance (either frequency or intensity) are expected to enhance species richness. This will promote invasion resistance when complementarity is more important than species identity. Negative effects of severe disturbance on invasion resistance, due to reductions in species richness, can be either overcompensated or exacerbated by species identity effects, depending on the life‐traits becoming dominant within the native species pool. Different invasion resistance scenarios are generated when the diversity‐disturbance relationship is negative or positive monotonic. Predictions from these models were experimentally tested on rocky reefs. Macroalgal canopies differing in species richness (1 vs. 2 vs. 3) and identity, were exposed to either a moderate or a severe pulse disturbance. The effects of different canopy‐forming species on the seaweed, Caulerpa cylindracea, varied from positive (Cystoseira crinita) to neutral (Cystoseira barbata) to negative (Cystoseira compressa). After 2 years, severely disturbed plots were monopolized by C. compressa and supported less C. cylindracea. Our study shows that the effects of disturbance on invasion depend upon its intensity, the main mechanism through which biodiversity generates invasion resistance and the life‐traits selected within the native species pool. Disturbance can sustain invasion resistance when promoting the dominance of competitively subordinate species possessing traits that allow outperforming invaders. 相似文献
90.
Mihovil Brlek Ljiljana Iveša Vlatko Brčić Ana Santos Stjepan Ćorić Monika Milošević Radovan Avanić Massimo Devescovi Đurđica Pezelj Ivan Mišur Mirjana Miknić 《Facies》2018,64(3):25
Badenian (Middle Miocene) transgressive deepening-upward successions located in the NE part of Mt. Medvednica (North Croatian Basin, Pannonian Basin System) unconformably overlie Mesozoic basement. Triassic and Upper Cretaceous limestone pebbles, cobbles, and boulders of the Badenian basal conglomerates display abundant in situ bivalve borings of Gastrochaenolites and sponge borings of Entobia. This Gastrochaenolites-Entobia ichnoassemblage is related to the Entobia subichnofacies of the Trypanites ichnofacies, characterizing littoral rocky-shore environments (wave-cut platforms and marine transgressive surfaces with a low or null rate of sedimentation). Gastrochaenolites torpedo, Gastrochaenolites lapidicus, and Entobia recorded in Badenian basal conglomerates (compared with modern Northern Adriatic rocky-shore environments), enabled more precise palaeoenvironmental interpretations. The occurrence of G. torpedo (produced by lithophaginid bivalves) on all sides of individual limestone lithoclasts in the Gornje Ore?je basal conglomerate, coupled with truncation of the formation (possibly indicating multiphase colonization), reflect gravel transport, roll-over, overturning and erosion by wave action in high-energy rocky-shore settings. Gornje Psarjevo-2 basal conglomerate boulders were probably not subjected to significant movement and abrasion, as suggested by good preservation of both G. lapidicus (potentially produced by gastrochaenid bivalves), associated G. torpedo, as well as abundant shallow Entobia borings. The Badenian Gastrochaenolites-Entobia ichnoassemblage also could be the result of a composite development. However, direct cross-cutting relationships between G. torpedo and G. lapidicus and/or Entobia were rarely observed. In addition, Badenian boring tracemakers might have coexisted at the same water depth. Northeast Mt. Medvednica Badenian successions probably formed during different Central Paratethys transgressive pulses (NN5 and NN6 Zones). However, exact timing of Badenian transgressions, stratigraphic correlations and tectono-eustatic implications are unresolved, due to sparsely integrated biostratigraphic and high-precision geochronological studies of Early–Middle Miocene North Croatian Basin deposits and due to the absence of a uniform biostratigraphic zonation and regional chronostratigraphic division of Central Paratethys. 相似文献