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991.
Lamp B Riedel C Roman-Sosa G Heimann M Jacobi S Becher P Thiel HJ Rümenapf T 《Journal of virology》2011,85(7):3607-3620
Proteolytic processing of polyproteins is considered a crucial step in the life cycle of most positive-strand RNA viruses. An enhancement of NS2-3 processing has been described as a major difference between the noncytopathogenic (non-CP) and the cytopathogenic (CP) biotypes of pestiviruses. The effects of accelerated versus delayed NS2-3 processing on the maturation of the other nonstructural proteins (NSP) have never been compared. In this study, we analyzed the proteolytic processing of NSP in Classical swine fever virus (CSFV). Key to the investigation was a panel of newly developed monoclonal antibodies (MAbs) that facilitated monitoring of all nonstructural proteins involved in virus replication (NS2, NS3, NS4A, NS5A, and NS5B). Applying these MAbs in Western blotting and radioimmunoprecipitation allowed an unambiguous identification of the mature proteins and precursors in non-CP CSFV-infected cells. Furthermore, the kinetics of processing were determined by pulse-chase analyses for non-CP CSFV, CP CSFV, and a CP CSFV replicon. A slow but constant processing of NS4A/B-5A/B occurred in non-CP CSFV-infected cells, leading to balanced low-level concentrations of mature NSP. In contrast, the turnover of the polyprotein precursors was three times faster in CP CSFV-infected cells and in cells transfected with a CP CSFV replicon, causing a substantial increase of mature NSP concentrations. We conclude that a delayed processing not only of NS3 but further of all NSP represents a hallmark of regulation in non-CP pestiviruses. 相似文献
992.
Tina Schultheiss Nicole Stolte‐Leeb Sieghart Sopper Christiane Stahl‐Hennig 《Journal of medical primatology》2011,40(1):41-51
Background Rhesus monkeys play a central role in model studies on human infectious diseases, and often mucosal organs are affected by these pathogens, e.g. HIV. However, a comparative investigation into lymphocyte composition from different mucosal tissues is still missing. Methods Lymphocyte composition of duodenum, jejunum, ileum, colon, vagina, cervix, uterus and bronchoalveolar lavage from healthy rhesus monkeys was characterized in detail by flow cytometry. Moreover, we compared the lymphocyte proportions from intestinal biopsies with resections. Results All mucosal tissues exhibited higher values of CD8+, CD4+ CCR5+ and CD45RA? memory T cells than blood, but similar levels of total T cells. Especially within the four gut sites, the lymphocyte composition varied significantly. The relative proportions of lymphocyte subsets from duodenal and colonic biopsies compared to resections differed. Conclusion The lymphocyte composition highly varies between different mucosal sites, and data obtained from biopsy and necropsy samples were mostly not comparable. 相似文献
993.
994.
Legume species differ in the responses of their functional traits to plant diversity 总被引:1,自引:0,他引:1
Christiane Roscher Bernhard Schmid Nina Buchmann Alexandra Weigelt Ernst-Detlef Schulze 《Oecologia》2011,165(2):437-452
Plants can respond to environmental impacts by variation in functional traits, thereby increasing their performance relative
to neighbors. We hypothesized that trait adjustment should also occur in response to influences of the biotic environment,
in particular different plant diversity of the community. We used 12 legume species as a model and assessed their variation
in morphological, physiological, life-history and performance traits in experimental grasslands of different plant species
(1, 2, 4, 8, 16 and 60) and functional group (1–4) numbers. Mean trait values and their variation in response to plant diversity
varied among legume species and from trait to trait. The tall-growing Onobrychis viciifolia showed little trait variation in response to increasing plant diversity, whereas the species with shorter statures responded
in apparently adaptive ways. The formation of longer shoots with elongated internodes, increased biomass allocation to supporting
tissue at the cost of leaf mass, reduced branching, higher specific leaf areas and lower foliar δ13C values indicated increasing efforts for light acquisition in more diverse communities. Although leaf nitrogen concentrations
and shoot biomass:nitrogen ratios were not affected by increasing plant diversity, foliar δ15N values of most legumes decreased and the application of the 15N natural abundance method suggested that they became more reliant on symbiotic N2 fixation. Some species formed fewer inflorescences and delayed flowering with increasing community diversity. The observed
variation in functional traits generally indicated strategies of legumes to optimize light and nutrient capturing, but they
were largely species-dependent and only partly attributable to increasing canopy height and community biomass with increasing
plant diversity. Thus, the analysis of individual plant species and their adjustment to growth conditions in communities of
increasing plant diversity is essential to get a deeper insight into the mechanisms behind biodiversity–ecosystem functioning
relationships. 相似文献
995.
Osmotic adjustment in chickpea (Cicer arietinum L.) results in no yield benefit under terminal drought 总被引:2,自引:0,他引:2
Turner NC Abbo S Berger JD Chaturvedi SK French RJ Ludwig C Mannur DM Singh SJ Yadava HS 《Journal of experimental botany》2007,58(2):187-194
Variation in osmotic adjustment (OA) among chickpea (Cicer arietinumL.) cultivars has been observed when exposed to terminal drought,but some studies suggest that this benefits yield while otherssuggest it does not benefit yield in water-limited environments.In the present study, parents differing in OA were crossed anda set of advanced breeding lines (ABLs) developed for yieldtesting. The variation in OA during podding was measured underterminal drought in the F2, F3, F7, and F8 progeny and in theparents by either rehydrating the leaves before sampling forosmotic potential (OP) or by measuring the relative water content(RWC) and OP on adjacent leaves for the calculation of the OPat full turgor. Yields were measured in the F8 progeny underterminal drought in Australia and India. While differences inOA were measured in the chickpea lines and parents, OA variedfrom year to year and did not consistently benefit yield whenmeasured in the field under terminal drought. In Australia,differences in OA were not associated with any yield benefitin any year, while in India early flowering resulted in higheryields at three of the four sites, and OA had an inconsistenteffect on seed yields. A comparison of OP at full turgor measuredafter rehydration and from measurements of RWC and OP showedthat the rehydration technique underestimated OA. The lack ofcontribution of OA to yield of chickpea is discussed. Key words: Advanced breeding lines, early flowering, phenology, terminal drought, yield components 相似文献
996.
Transcriptional targeting of B cells for induction of peripheral CD8 T cell tolerance 总被引:1,自引:0,他引:1
Werner-Klein M Dresch C Marconi P Brocker T 《Journal of immunology (Baltimore, Md. : 1950)》2007,178(12):7738-7746
997.
Renolleau S Fau S Goyenvalle C Joly LM Chauvier D Jacotot E Mariani J Charriaut-Marlangue C 《Journal of neurochemistry》2007,100(4):1062-1071
Hypoxia-ischaemia in the developing brain results in brain injury with prominent features of apoptosis. In the present study, a third generation dipeptidyl broad-spectrum caspase inhibitor, quinoline-Val-Asp(Ome)-CH2-O-phenoxy (Q-VD-OPh), was tested in a model of unilateral focal ischaemia with reperfusion in 7-day-old rats. Q-VD-OPh (1 mg/kg, i.p.) reduced cell death, resulting in significant neuroprotection at 48 h of recovery (infarct volume of 12.6 +/- 2.8 vs. 24.3 +/- 2.2%, p = 0.006). The neuroprotective effects observed at 48 h post-ischaemia hold up at 21 days of survival time and attenuate neurological dysfunction. Analysis by gender revealed that females were strongly protected (6.7 +/- 3.3%, p = 0.006), in contrast to males in which there was no significant effect, when Q-VD-OPh was given after clip removal on the left common carotid artery. Immunoblot analysis demonstrated that Q-VD-OPh inhibits caspase 3 cleavage into its p17 active form and caspase 1 up-regulation and cleavage in vivo. Following ischaemia in P7 rats, males and females displayed different time course and pattern of cytochrome c release and active p17 caspase 3 during the first 24 h of recovery. In contrast, no significant difference was observed for caspase 1 expression between genders. These results indicate that ischaemia activates caspases shortly after reperfusion and that the sex of the animal may strongly influences apoptotic pathways in the pathogenesis of neonatal brain injury. The specificity, effectiveness, and reduced toxicity of Q-VD-OPh may determine the potential use of peptide-derived irreversible caspase inhibitors as promising therapeutics. 相似文献
998.
The hypothesis that plant species diversity and genetic variation of the host species decrease the severity of plant diseases
is supported by studies of agricultural systems, but experimental evidence from more complex systems is scarce. In an experiment
with grassland communities of varying species richness (1, 2, 4, 8, 16, and 60 species) and functional group richness (1,
2, 3, and 4 functional groups), we used different cultivars of Lolium perenne (perennial ryegrass) to study effects of biodiversity and cultivar identity on the occurrence and severity of foliar fungal
diseases caused by Puccinia coronata (crown rust) and P. graminis (stem rust). Cultivar monocultures of perennial ryegrass revealed strong differences in pathogen susceptibility among these
cultivars. Disease intensity caused by both rust fungi decreased significantly with growing species richness of species mixtures.
The response to the diversity gradient was related to the decreased density and size of the host individuals with increasing
species richness. The occurrence of other grass species known to be possible hosts of the pathogens in the experimental mixtures
did not promote disease intensity in L. perenne, indicating that there was a high host specificity of pathogen strains. Differences in pathogen susceptibility among perennial
ryegrass cultivars persisted independent of diversity treatment, host density and host individual size, but resulted in a
cultivar-specific pattern of changes in pathogen infestation across the species-richness gradient. Our study provided evidence
that within-species variation in pathogen susceptibility and competitive interactions of the host species with the environment,
as caused by species diversity treatments, are key determinants of the occurrence and severity of fungal diseases.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
999.
Developmental genes have pleiotropic effects on plant morphology and source capacity, eventually impacting on seed protein content and productivity in pea 下载免费PDF全文
Burstin J Marget P Huart M Moessner A Mangin B Duchene C Desprez B Munier-Jolain N Duc G 《Plant physiology》2007,144(2):768-781
Increasing pea (Pisum sativum) seed nutritional value and particularly seed protein content, while maintaining yield, is an important challenge for further development of this crop. Seed protein content and yield are complex and unstable traits, integrating all the processes occurring during the plant life cycle. During filling, seeds are the main sink to which assimilates are preferentially allocated at the expense of vegetative organs. Nitrogen seed demand is satisfied partly by nitrogen acquired by the roots, but also by nitrogen remobilized from vegetative organs. In this study, we evaluated the respective roles of nitrogen source capacity and sink strength in the genetic variability of seed protein content and yield. We showed in eight genotypes of diverse origins that both the maximal rate of nitrogen accumulation in the seeds and nitrogen source capacity varied among genotypes. Then, to identify the genetic factors responsible for seed protein content and yield variation, we searched for quantitative trait loci (QTL) for seed traits and for indicators of sink strength and source nitrogen capacity. We detected 261 QTL across five environments for all traits measured. Most QTL for seed and plant traits mapped in clusters, raising the possibility of common underlying processes and candidate genes. In most environments, the genes Le and Afila, which control internode length and the switch between leaflets and tendrils, respectively, determined plant nitrogen status. Depending on the environment, these genes were linked to QTL of seed protein content and yield, suggesting that source-sink adjustments depend on growing conditions. 相似文献
1000.
Oxygen, a source of life and stress 总被引:5,自引:0,他引:5