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51.
The aim of the investigation was to study the influence of the rate of water uptake on the uptake of sulphate at supernormal rates of water flow. This was achieved by reducing the size of the root system of 42 days old Ricinus plants. The rate of water flow through the root increased 3 times by reducing the root system to 20 percent. This did not change the retention of sulphate in the roots. The uptake of sulphate was proportional to the size of the root system and thus independent of the rate of water flow while the water uptake (transpiration) was a function of the size of the shoot and the resistance of the root. This was contrary to the conditions at a moderate rate of water flow, when water and sulphate uptake followed each other. The results are discussed in terms of the salt uptake as a series of active and passive processes. 相似文献
52.
Max Lundberg Xiuqin Zhong Anna Konrad Remi‐Andr Olsen Lars Rberg 《Molecular ecology》2020,29(11):1990-2003
Pathogen‐mediated balancing selection is commonly considered to play an important role in the maintenance of genetic diversity, in particular in immune genes. However, the factors that may influence which immune genes are the targets of such selection are largely unknown. To address this, here we focus on Pattern Recognition Receptor (PRR) signalling pathways, which play a key role in innate immunity. We used whole‐genome resequencing data from a population of bank voles (Myodes glareolus) to test for associations between balancing selection, pleiotropy and gene function in a set of 123 PRR signalling pathway genes. To investigate the effect of gene function, we compared genes encoding (a) receptors for microbial ligands versus downstream signalling proteins, and (b) receptors recognizing components of microbial cell walls, flagella and capsids versus receptors recognizing features of microbial nucleic acids. Analyses based on the nucleotide diversity of full coding sequences showed that balancing selection primarily targeted receptor genes with a low degree of pleiotropy. Moreover, genes encoding receptors recognizing components of microbial cell walls etc. were more important targets of balancing selection than receptors recognizing nucleic acids. Tests for localized signatures of balancing selection in coding and noncoding sequences showed that such signatures were mostly located in introns, and more evenly distributed among different functional categories of PRR pathway genes. The finding that signatures of balancing selection in full coding sequences primarily occur in receptor genes, in particular those encoding receptors for components of microbial cell walls etc., is consistent with the idea that coevolution between hosts and pathogens is an important cause of balancing selection on immune genes. 相似文献
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Ilan Kurz Lars Oddsson Itshak Melzer 《Journal of electromyography and kinesiology》2013,23(4):814-819
ObjectiveOlder adults who have recently fallen demonstrate increased postural sway compared with non-fallers. However, the differences in postural control between older adults who were seriously injured (SI) as a result of a fall, compared with those who fell but were not injured (NSI) and non-fallers (NFs), has not been investigated. The objective of the present study was to investigate the underlying postural control mechanisms related to injuries resulting from a fall.MethodsBoth traditional postural sway measures of foot center-of-pressure (CoP) displacements and fractal measures, the Stabilogram-Diffusion Analysis (SDA), were used to characterize the postural control. One hundred older adults aged 65–91 years were tested during narrow base upright stance in eyes closed condition; falls were monitored over a 1-year period.ResultsForty-nine older adults fell during the 1-year follow-up, 13 were seriously injured as a result of a fall (SI), 36 were not injured (NSI), and 49 were non-fallers (NFs); two passed away. The SDA showed significantly higher short-term diffusion coefficients and critical displacements in SI in the anterior–posterior direction compared with both NSI and NF. However, in the medio-lateral direction there were no statistically significant differences between groups. For the traditional measures of sway, the average anterior–posterior CoP range was also larger in SI individuals.ConclusionsThis work suggests that older fallers with a deterioration of anterior–posterior postural control may be at higher risk of serious injury following fall events. 相似文献
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Asbjørn T. Binderup Lars Arendt-Nielsen 《Computer methods in biomechanics and biomedical engineering》2013,16(6):677-683
The aim of this study was to investigate and present a new mapping method to describe muscle pain sensitivity based on the assessment of pressure pain threshold (PPT) over the trapezius muscle. PPT data were recorded from 36 points in 20 healthy males using a standardised grid. Points were clustered using the K-means algorithm with a fixed initialisation procedure. The total number of clusters was determined on the basis of (1) R 2 evaluation of the clustering outcome compared against a desired 95% reduction in variance criterion and (2) the number of empty clusters. A minimum of three clusters were found which fulfilled the criteria. The proposed method enables the identification of a relation between the muscle subdivisions and pressure pain sensitivity within the trapezius. Further, the cluster analysis will enable the study of differences in pain sensitivity distributions between patients and controls and quantify the effect of intervention (physical or pharmacological treatments). 相似文献
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Antibodies and antibody-based drugs are currently the fastest-growing class of therapeutics. Over the last three decades, more than 30 therapeutic monoclonal antibodies and derivatives thereof have been approved for and successfully applied in diverse indication areas including cancer, organ transplants, autoimmune/inflammatory disorders, and cardiovascular disease. The isotype of choice for antibody therapeutics is human IgG, whose Fc region contains a ubiquitous asparagine residue (N297) that acts as an acceptor site for N-linked glycans. The nature of these glycans can decisively influence the therapeutic performance of a recombinant antibody, and their absence or modification can lead to the loss of Fc effector functions, greater immunogenicity, and unfavorable pharmacokinetic profiles. However, recent studies have shown that aglycosylated antibodies can be genetically engineered to display novel or enhanced effector functions and that favorable pharmacokinetic properties can be preserved. Furthermore, the ability to produce aglycosylated antibodies in lower eukaryotes and bacteria offers the potential to broaden and simplify the production platforms and avoid the problem of antibody heterogeneity, which occurs when mammalian cells are used for production. In this review, we discuss the importance of Fc glycosylation focusing on the use of aglycosylated and glyco-engineered antibodies as therapeutic proteins. 相似文献
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Lars Vogt 《分类学与生物多样性》2013,11(3):257-270
Referring to European history of natural sciences as an example, I discuss the relation between development of standards and the emergence of new epistemic virtues. I distinguish standards relating to scientific argumentation from standards relating to data production. The former are based on truth-seeking epistemic virtues and use criteria of logical coherence and empirical grounding. They are important for the justification of an explanatory hypothesis. Data and metadata standards, on the other hand, concern the data record itself and all steps and actions taken during data production and are based on virtues of objectivity. In the second part I focus on data and metadata standards and argue that, in order to meet the requirements of eScience, the specification of the currently popular minimum information checklists should be complemented to cover four aspects: (i) content standards, which increase reproducibility and operational transparency of data production, (ii) concept standards, which increase the semantic transparency of the terms used in data records, (iii) nomenclatural standards, which provide stable and unambiguous links between the terms used and their underlying definitions or their real referents, and (iv) format standards, which increase compatibility and computer-parsability of data records. I discuss the role of scientific terminology for standardizing data and the need for using semantically standardized and formalized data-reporting languages in the form of controlled vocabularies and ontologies for establishing content standards for data in the life sciences. Finally I comment on the necessity of community participation in the development and application of standards and in making data openly available. 相似文献
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Lars Tramsen Stanislaw Schmidt Halvard Boenig Jean-Paul Latgé Cornelia Lass-Flörl Frauke Roeger Erhard Seifried Thomas Klingebiel Thomas Lehrnbecher 《Cytotherapy》2013,15(3):344-351
Background aimsInvasive fungal infections, in particular, infections caused by Candida, Aspergillus and mucormycetes, are a major cause of morbidity and mortality in patients undergoing allogeneic hematopoietic stem cell transplantation. Adoptive transfer of donor-derived anti-fungal T cells shows promise to restore immunity and to offer a cure. Because T cells recognize only specific epitopes, the low rate of patients in which the causal fungal pathogen can be identified and the considerable number of patients with co-infection with several genera or species of fungi significantly limit the application of adoptive immunotherapy.MethodsUsing the interferon-γ secretion assay, we isolated multi-specific human anti-fungal T cells after simultaneous stimulation with cellular extracts of Aspergillus fumigatus, Candida albicans and Rhizopus oryzae. Cells were phenotypically and functionally characterized by flow cytometry.ResultsOf a total of 1.1 × 109 peripheral blood mononuclear cells, a median number of 5.2 × 107 CD3+CD4+ T cells was generated within 12 days. This cell population consisted of activated memory TH1 cells and reproducibly responded to a multitude of Aspergillus spp., Candida spp. and mucormycetes with interferon-γ production. On re-stimulation, the generated T cells proliferated and enhanced anti-fungal activity of phagocytes and showed reduced alloreactivity compared with the original cell fraction.ConclusionsOur rapid and simple method of simultaneously generating functionally active multi-specific T cells that recognize a wide variety of medically relevant fungi may form the basis for future clinical trials investigating adoptive immunotherapy in allogeneic hematopoietic stem cell transplantation recipients with invasive fungal infection. 相似文献
60.
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