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排序方式: 共有1372条查询结果,搜索用时 31 毫秒
31.
Martin Kemler María P. Martín M. Teresa Telleria Angela M. Schäfer Andrey Yurkov Dominik Begerow 《Organisms Diversity & Evolution》2013,13(2):111-126
Anther smuts in the genus Microbotryum often show very high host specificity toward their caryophyllaceous hosts, but some of the larger host groups such as Dianthus are crucially undersampled for these parasites so that the question of host specificity cannot be answered conclusively. In this study we sequenced the internal transcribed spacer (ITS) region of members of the Microbotryum dianthorum species complex as well as their Dianthus hosts. We compared phylogenetic trees of these parasites including sequences of anther smuts from other Caryophyllaceae, mainly Silene, with phylogenies of Caryophyllaceae that are known to harbor anther smuts. Additionally we tested whether observed patterns in parasites are due to shared ancestry or if geographic separation is a factor that should be taken into consideration in delimitating species. Parasites on Dianthus showed mainly an arbitrary distribution on Dianthus hosts, whereas parasites on other Caryophyllaceae formed well-supported monophyletic clades that corresponded to restricted host groups. The same pattern was observed in the Caryophyllaceae studied: morphologically described Dianthus species did not correspond well with monophyletic clades based on molecular data, whereas other Caryophyllaceae mainly did. We suggest that these different patterns primarily result from different breeding systems and speciation times between different host groups as well as difficulties in species delimitations in the genus Dianthus. 相似文献
32.
Tracie Pennimpede Stefanie Wolter Lars Wittler Anne‐Karoline Ebert Wolfgang Rösch Raimund Stein Enrika Bartels Dominik Schmidt Thomas M. Boemers Eberhard Schmiedeke Per Hoffmann Susanne Moebus Bernhard G. Herrmann Markus M. Nöthen Heiko Reutter Michael Ludwig 《Birth defects research. Part A, Clinical and molecular teratology》2013,97(3):133-139
33.
Carsten Frühbeis Dominik Fr?hlich Wen Ping Kuo Jesa Amphornrat Sebastian Thilemann Aiman S. Saab Frank Kirchhoff Wiebke M?bius Sandra Goebbels Klaus-Armin Nave Anja Schneider Mikael Simons Matthias Klugmann Jacqueline Trotter Eva-Maria Kr?mer-Albers 《PLoS biology》2013,11(7)
Reciprocal interactions between neurons and oligodendrocytes are not only crucial for myelination, but also for long-term survival of axons. Degeneration of axons occurs in several human myelin diseases, however the molecular mechanisms of axon-glia communication maintaining axon integrity are poorly understood. Here, we describe the signal-mediated transfer of exosomes from oligodendrocytes to neurons. These endosome-derived vesicles are secreted by oligodendrocytes and carry specific protein and RNA cargo. We show that activity-dependent release of the neurotransmitter glutamate triggers oligodendroglial exosome secretion mediated by Ca2+ entry through oligodendroglial NMDA and AMPA receptors. In turn, neurons internalize the released exosomes by endocytosis. Injection of oligodendroglia-derived exosomes into the mouse brain results in functional retrieval of exosome cargo in neurons. Supply of cultured neurons with oligodendroglial exosomes improves neuronal viability under conditions of cell stress. These findings indicate that oligodendroglial exosomes participate in a novel mode of bidirectional neuron-glia communication contributing to neuronal integrity. 相似文献
34.
Kathrin Schüller Dominik Bühler Nikolaus Plesnila 《Journal of visualized experiments : JoVE》2013,(81)
In this video publication a standardized mouse model of subarachnoid hemorrhage (SAH) is presented. Bleeding is induced by endovascular Circle of Willis perforation (CWp) and proven by intracranial pressure (ICP) monitoring. Thereby a homogenous blood distribution in subarachnoid spaces surrounding the arterial circulation and cerebellar fissures is achieved. Animal physiology is maintained by intubation, mechanical ventilation, and continuous on-line monitoring of various physiological and cardiovascular parameters: body temperature, systemic blood pressure, heart rate, and hemoglobin saturation. Thereby the cerebral perfusion pressure can be tightly monitored resulting in a less variable volume of extravasated blood. This allows a better standardization of endovascular filament perforation in mice and makes the whole model highly reproducible. Thus it is readily available for pharmacological and pathophysiological studies in wild type and genetically altered mice. 相似文献
35.
Lorena Esposito-Bauer Tobias Saam Iman Ghodrati Jaroslav Pelisek Peter Heider Matthias Bauer Petra Wolf Angelina Bockelbrink Regina Feurer Dominik Sepp Claudia Winkler Peter Zepper Tobias Boeckh-Behrens Matthias Riemenschneider Bernhard Hemmer Holger Poppert 《PloS one》2013,8(7)
Purpose
The aim of this study was to investigate prospectively whether MRI plaque imaging can identify patients with asymptomatic carotid artery stenosis who have an increased risk for future cerebral events. MRI plaque imaging allows categorization of carotid stenosis into different lesion types (I–VIII). Within these lesion types, lesion types IV–V and VI are regarded as rupture-prone plaques, whereas the other lesion types represent stable ones.Methods
Eighty-three consecutive patients (45 male (54.2%); age 54–88 years (mean 73.2 years)) presenting with an asymptomatic carotid stenosis of 50–99% according to ECST-criteria were recruited. Patients were imaged with a 1.5-T scanner. T1-, T2-, time-of-flight-, and proton-density weighted studies were performed. The carotid plaques were classified as lesion type I–VIII. Clinical endpoints were ischemic stroke, TIA or amaurosis fugax. Survival analysis and log rank test were used to ascertain statistical significance.Results
Six out of 83 patients (7.2%) were excluded: 4 patients had insufficient MR image quality; 1 patient was lost-to-follow-up; 1 patient died shortly after the baseline MRI plaque imaging. The following results were obtained by analyzing the remaining 77 patients. The mean time of follow-up was 41.1 months.During follow-up, n = 9 (11.7%) ipsilateral ischemic cerebrovascular events occurred. Only patients presenting with the high-risk lesion types IV–V and VI developed an ipsilateral cerebrovascular event versus none of the patients presenting with the stable lesion types III, VII, and VIII (n = 9 (11.7%) vs. n = 0 (0%) during follow-up). Event-free survival was higher among patients with the MRI-defined stable lesion types (III, VII, and VIII) than in patients with the high-risk lesion types (IV–V and VI) (log rank test P<0.0001).Conclusions
MRI plaque imaging has the potential to identify patients with asymptomatic carotid stenosis who are particularly at risk of developing future cerebral ischemia. MRI could improve selection criteria for invasive therapy in the future. 相似文献36.
It is evident that parental depressive symptoms negatively influence adolescent behavior and various psychosocial outcomes. Certain family types like families with a chronically ill parent and single parent families are more vulnerable to parental depressive symptoms. However, the relationship between these symptoms, family type, and adolescent functioning remains largely unclear. This study examined relations between self-report of parental depressive symptoms and adolescent functioning in 86 two-parent families including a parent with a chronic medical condition, 94 families with healthy single parents, and 69 families with 2 healthy parents (comparison group). Parents completed the Beck Depression Inventory. Adolescents filled in the Youth Self-Report measuring problem behavior, and other instruments measuring psychosocial outcomes (stress, grade point average, school problems, and self-esteem). Multilevel analyses were used to examine the effects of family type, parental depressive symptoms, adolescents'' gender and age, and interaction effects on adolescent functioning. The results indicated that adolescents with chronically ill and single parents had a lower grade point average (p<.01) than the comparison group. Adolescents of single parents reported more internalizing problems (p<.01) and externalizing problems (p<.05) than children from the other family types. Parental depressive symptoms were strongly related to child report of stress (p<.001). Adolescents of depressed chronically ill parents were particularly vulnerable to internalizing problems (interaction effect, p<.05). Older children and girls, and especially older girls, displayed more internalizing problems and stress. It can be concluded that growing up with a chronically ill parent in a family with 2 parents may have less impact on adolescent problem behavior than growing up in a single parent family. Health practitioners are encouraged to be attentive to the unique and combined influence of family type and parental depressive symptoms on adolescent functioning. Older and female adolescents deserve particular attention. 相似文献
37.
38.
Dominik P. J. Heib Kerstin Hoedlmoser Peter Anderer Josef Zeitlhofer Georg Gruber Wolfgang Klimesch Manuel Schabus 《PloS one》2013,8(12)
There is growing evidence of the active involvement of sleep in memory consolidation. Besides hippocampal sharp wave-ripple complexes and sleep spindles, slow oscillations appear to play a key role in the process of sleep-associated memory consolidation. Furthermore, slow oscillation amplitude and spectral power increase during the night after learning declarative and procedural memory tasks. However, it is unresolved whether learning-induced changes specifically alter characteristics of individual slow oscillations, such as the slow oscillation up-state length and amplitude, which are believed to be important for neuronal replay. 24 subjects (12 men) aged between 20 and 30 years participated in a randomized, within-subject, multicenter study. Subjects slept on three occasions for a whole night in the sleep laboratory with full polysomnography. Whereas the first night only served for adaptation purposes, the two remaining nights were preceded by a declarative word-pair task or by a non-learning control task. Slow oscillations were detected in non-rapid eye movement sleep over electrode Fz. Results indicate positive correlations between the length of the up-state as well as the amplitude of both slow oscillation phases and changes in memory performance from pre to post sleep. We speculate that the prolonged slow oscillation up-state length might extend the timeframe for the transfer of initial hippocampal to long-term cortical memory representations, whereas the increase in slow oscillation amplitudes possibly reflects changes in the net synaptic strength of cortical networks. 相似文献
39.
Fungi are key players in terrestrial ecosystem functions. They are not only indispensable symbionts of most of the terrestrial plants, but can also interact with almost all organisms and are the major decomposers of organic matter. Indeed, they are involved in most ecosystem services, so much that life on earth would not have evolved without them. Competition among fungi and with other organism groups has driven evolution of offensive and defensive mechanisms, including the production of secondary metabolites, which continue to be widely unexplored. In addition, fungal plant parasites threaten the global agricultural production and are therefore of highest relevance for human health and survival. Given the ecological and economical relevance of fungi, advancement of other biological and physical sciences are impeded because mycology—the science devoted to the study of fungi—is insufficiently recognized as a major field of life science and supported in basic and applied research and economic contexts. 相似文献
40.
Dominik Thimm Melanie Knospe Aliaa Abdelrahman Miguel Moutinho Bernt B. A. Alsdorf Ivar von Kügelgen Anke C. Schiedel Christa E. Müller 《Purinergic signalling》2013,9(3):415-426
The nucleobase adenine has previously been reported to activate G protein-coupled receptors in rat and mouse. Adenine receptors (AdeR) thus constitute a new family of purine receptors, for which the designation “P0-receptors” has been suggested. We now describe the cloning and characterization of two new members of the AdeR family from mouse (MrgA10, termed mAde1R) and hamster (cAdeR). Both receptors were expressed in Sf9 insect cells, and radioligand binding studies were performed using [3H]adenine. Specific binding of the radioligand was detected in transfected, but not in untransfected cells, and K D values of 286 nM (mAde1R, B max 1.18 pmol/mg protein) and 301 nM (cAdeR, B max 17.7 pmol/mg protein), respectively, were determined. A series of adenine derivatives was investigated in competition binding assays. Minor structural modifications generally led to a reduction or loss of affinity, with one exception: 2-fluoroadenine was at least as potent as adenine itself at the cAdeR. Structure–activity relationships at all AdeR orthologs and subtypes investigated so far were similar, but not identical. For functional analyses, the cAdeR was homologously expressed in Chinese hamster ovary (CHO) cells, while the mAde1R was heterologously expressed in 1321N1 astrocytoma cells. Like the previously described AdeRs from rat (rAdeR) and mouse (mAde2R), the mAde1R (EC50 9.77 nM) and the cAdeR (EC50 51.6 nM) were coupled to inhibition of adenylate cyclase. In addition, the cAdeR from hamster expressed in CHO cells produced an increase in intracellular calcium concentrations (EC50 6.24 nM) and was found to be additionally coupled to Gq proteins. 相似文献