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971.
Modelling the distribution and compositional variation of plant communities at the continental scale 下载免费PDF全文
Borja Jiménez‐Alfaro Susana Suárez‐Seoane Milan Chytrý Stephan M. Hennekens Wolfgang Willner Michal Hájek Emiliano Agrillo Jose M. Álvarez‐Martínez Ariel Bergamini Henry Brisse Jörg Brunet Laura Casella Daniel Dítě Xavier Font François Gillet Petra Hájková Florian Jansen Ute Jandt Zygmunt Kącki Jonathan Lenoir John S. Rodwell Joop H. J. Schaminée Lucia Sekulová Jozef Šibík Željko Škvorc Ioannis Tsiripidis 《Diversity & distributions》2018,24(7):978-990
Aim
We investigate whether (1) environmental predictors allow to delineate the distribution of discrete community types at the continental scale and (2) how data completeness influences model generalization in relation to the compositional variation of the modelled entities.Location
Europe.Methods
We used comprehensive datasets of two community types of conservation concern in Europe: acidophilous beech forests and base‐rich fens. We computed community distribution models (CDMs) calibrated with environmental predictors to predict the occurrence of both community types, evaluating geographical transferability, interpolation and extrapolation under different scenarios of sampling bias. We used generalized dissimilarity modelling (GDM) to assess the role of geographical and environmental drivers in compositional variation within the predicted distributions.Results
For the two community types, CDMs computed for the whole study area provided good performance when evaluated by random cross‐validation and external validation. Geographical transferability provided lower but relatively good performance, while model extrapolation performed poorly when compared with interpolation. Generalized dissimilarity modelling showed a predominant effect of geographical distance on compositional variation, complemented with the environmental predictors that also influenced habitat suitability.Main conclusions
Correlative approaches typically used for modelling the distribution of individual species are also useful for delineating the potential area of occupancy of community types at the continental scale, when using consistent definitions of the modelled entity and high data completeness. The combination of CDMs with GDM further improves the understanding of diversity patterns of plant communities, providing spatially explicit information for mapping vegetation diversity and related habitat types at large scales.972.
Sara Jiménez-Puertas David Sánchez-Artuñedo Marcelino Hermida-López 《Reports of Practical Oncology and Radiotherapy》2018,23(2):121-125
Aim
This work aims to achieve the highest possible monitor units (MU) reduction using the MU Objective tool included in the Eclipse treatment planning system, while preserving the plan quality.Background
The treatment planning system Eclipse (Varian Medical Systems, Palo Alto, CA) includes a control mechanism for the number of monitor units of volumetric modulated arc therapy (VMAT) plans, named the MU Objective tool.Material and methods
Forty prostate plans, 20 gynecological plans and 20 head and neck plans designed with VMAT were retrospectively studied. Each plan (base plan) was optimized without using the MU Objective tool, and it was re-optimized with different values of the Maximum MU (MaxMU) parameter of the MU Objective tool. MU differences were analyzed with a paired samples t-test and changes in plan quality were assessed with a set of parameters for OARs and PTVs.Results
The average relative MU difference considering all treatment sites, was the highest when MaxMU = 400 (?4.2%, p < 0.001). For prostate plans, the lowest was obtained (?3.7%, p < 0.001). For head and neck plans was ?7.3% (p < 0.001) and for gynecological plans was 7.0% (p = 0.002). Although similar MU reductions were observed for both sites, for some gynecological plans maximum differences were greater than 10%. All the assessed parameters for PTVs and OARs sparing showed average differences below 2%.Conclusion
For the three studied clinical sites, establishing MaxMU = 400 led to the optimum MU reduction, maintaining the original dose distribution and dosimetric parameters practically unaltered. 相似文献973.
Peter L. Falkingham Karl T. Bates Marco Avanzini Matthew Bennett Emese M. Bordy Brent H. Breithaupt Diego Castanera Paolo Citton Ignacio Díaz‐Martínez Jim O. Farlow Anthony R. Fiorillo Stephen M. Gatesy Patrick Getty Kevin G. Hatala Jahn J. Hornung James A. Hyatt Hendrik Klein Jens N. Lallensack Anthony J. Martin Daniel Marty Neffra A. Matthews Christian A. Meyer Jesper Milàn Nicholas J. Minter Novella L. Razzolini Anthony Romilio Steven W. Salisbury Lara Sciscio Ikuko Tanaka Ashleigh L. A. Wiseman L. D. Xing Matteo Belvedere 《Palaeontology》2018,61(4):469-480
The collection and dissemination of vertebrate ichnological data is struggling to keep up with techniques that are becoming commonplace in the wider palaeontological field. A standard protocol is required to ensure that data is recorded, presented and archived in a manner that will be useful both to contemporary researchers, and to future generations. Primarily, our aim is to make the 3D capture of ichnological data standard practice, and to provide guidance on how such 3D data can be communicated effectively (both via the literature and other means) and archived openly and in perpetuity. We recommend capture of 3D data, and the presentation of said data in the form of photographs, false‐colour images, and interpretive drawings. Raw data (3D models of traces) should always be provided in a form usable by other researchers (i.e. in an open format). If adopted by the field as a whole, the result will be a more robust and uniform literature, supplemented by unparalleled availability of datasets for future workers. 相似文献
974.
Khushbu Shah Xin Lin Sherry F. Queener Vivian Cody Jim Pace Aleem Gangjee 《Bioorganic & medicinal chemistry》2018,26(9):2640-2650
To combine the potency of trimetrexate (TMQ) or piritrexim (PTX) with the species selectivity of trimethoprim (TMP), target based design was carried out with the X-ray crystal structure of human dihydrofolate reductase (hDHFR) and the homology model of Pneumocystis jirovecii DHFR (pjDHFR). Using variation of amino acids such as Met33/Phe31 (in pjDHFR/hDHFR) that affect the binding of inhibitors due to their distinct positive or negative steric effect at the active binding site of the inhibitor, we designed a series of substituted-pyrrolo[2,3-d]pyrimidines. The best analogs displayed better potency (IC50) than PTX and high selectivity for pjDHFR versus hDHFR, with 4 exhibiting a selectivity for pjDHFR of 24-fold. 相似文献
975.
Eric Higgs Jim Harris Stephen Murphy Keith Bowers Richard Hobbs Willis Jenkins Jeremy Kidwell Nikita Lopoukhine Bethany Sollereder Katherine Suding Allen Thompson Steven Whisenant 《Restoration Ecology》2018,26(3):399-403
The Society for Ecological Restoration (SER) has long debated how to define best practices. We argue that a principles‐first approach offers more flexibility for restoration practitioners than a standards‐based approach, is consistent with the developmental stage of restoration, and functions more effectively at a global level. However, the solution is not as simple as arguing that one approach to professional practice is sufficient. Principles and standards can and do operate effectively together, but only if they are coordinated in a transparent and systematic way. Effective professional guidance results when standards anchored by principles function in a way that is contextual and evolving. Without that clear relation to principles, the tendency to promote performance standards may lead to a narrowing of restoration practice and reduction in the potential to resolve very difficult and diverse ecological and environmental challenges. We offer recommendations on how the evolving project of restoration policy by SER and other agencies and organizations can remain open and flexible. 相似文献
976.
Cryptic species and parallel genetic structuring in Lethrinid fish: Implications for conservation and management in the southwest Indian Ocean 下载免费PDF全文
Amy J. E. Healey Niall J. McKeown Amy L. Taylor Jim Provan Warwick Sauer Gavin Gouws Paul W. Shaw 《Ecology and evolution》2018,8(4):2182-2195
Analysis of genetic variation can provide insights into ecological and evolutionary diversification which, for commercially harvested species, can also be relevant to the implementation of spatial management strategies and sustainability. In comparison with other marine biodiversity hot spots, there has been less genetic research on the fauna of the southwest Indian Ocean (SWIO). This is epitomized by the lack of information for lethrinid fish, which support socioeconomically important fisheries in the region. This study combines comparative phylogeographic and population genetic analyses with ecological niche modeling to investigate historical and contemporary population dynamics of two species of emperor fish (Lethrinus mahsena and Lethrinus harak) across the SWIO. Both species shared similarly shallow phylogeographic patterns and modeled historical (LGM) habitat occupancies. For both species, allele frequency and kinship analyses of microsatellite variation revealed highly significant structure with no clear geographical pattern and nonrandom genetic relatedness among individuals within samples. The genetic patterns for both species indicate recurrent processes within the region that prevent genetic mixing, at least on timescales of interest to fishery managers, and the potential roles of recruitment variability and population isolation are discussed in light of biological and environmental information. This consistency in both historical and recurrent population processes indicates that the use of model species may be valuable in management initiatives with finite resources to predict population structure, at least in cases wherein biogeographic and ecological differences between taxa are minimized. Paradoxically, mtDNA sequencing and microsatellite analysis of samples from the Seychelles revealed a potential cryptic species occurring in sympatry with, and seemingly morphologically identical to, L. mahsena. BLAST results point to the likely misidentification of species and incongruence between voucher specimens, DNA barcodes, and taxonomy within the group, which highlights the utility and necessity of genetic approaches to characterize baseline biodiversity in the region before such model‐based methods are employed. 相似文献
977.
978.
Gugs Lushai Jim Hardie Richard Harrington 《Entomologia Experimentalis et Applicata》1996,81(1):113-115
Conclusion TastePROBE is a convenient and flexible electronic circuit designed to record action potentials from taste sensilla of insects. It facilitates the recording of slow potentials arising in taste sensilla, improves the signal to noise ratio, and preserves spike shapes. This new amplifier design combines excellent signal to noise ratio with complete compatibility as regards existing electrophysiological equipment.DC recordings have higher information content than filtered recordings. With DC recordings, spike shapes are not modified and thus better sorting is possible. Moreover, slow variations in the transepithelial potential (i.e. less than 10 Hz) are preserved. Both aspects are of considerable importance when studying the physiology of taste receptors. 相似文献
979.
Ulva rigida was cultivated in 7501 tanks at different densities with direct and continuous inflow (at 2, 4, 8 and 12 volumes d–1) of the effluents from a commercial marine fishpond (40 metric tonnes, Tm, of Sparus aurata, water exchange rate of 16 m3 Tm–1) in order to assess the maximum and optimum dissolved inorganic nitrogen (DIN) uptake rate and the annual stability of the Ulva tank biofiltering system. Maximum yields (40 g DW m–2 d–1) were obtained at a density of 2.5 g FW 1–1 and at a DIN inflow rate of 1.7 g DIN m–2 d–1. Maximum DIN uptake rates were obtained during summer (2.2 g DIN M–2 d–1), and minimum in winter (1.1 g DIN m–2 d–1) with a yearly average DIN uptake rate of 1.77 g DIN m–2 d–1 At yearly average DIN removal efficiency (2.0 g DIN m–2 d–1, if winter period is excluded), 153 m2 of Ulva tank surface would be needed to recover 100% of the DIN produced by 1 Tm of fish.Abbreviations DIN=
dissolved inorganic nitrogen (NH
inf4
sup+
+ NO
inf3
sup–
+ NO
inf2
sup–
);
- FW=
fresh weight;
- DW=
dry weight;
- PFD=
photon flux density;
- V=
DIN uptake rate 相似文献
980.
Pérez-Arellano JL Barrios MN Martín T Sánchez ML Buitrago JM Jiménez A 《Mediators of inflammation》1995,4(1):43-48
Hydrolytic enzymes are the major constituents of alveolar macrophages (AM) and have been shown to be involved in many aspects of the inflammatory pulmonary response. The aim of this study was to evaluate the role of lysosomal enzymes in the acute phase of hypersensitivity pneumonitis (HPs). An experimental study on AM lysosomal enzymes of an HP-guinea-pig model was performed. The results obtained both in vivo and in vitro suggest that intracellular enzymatic activity decrease is, at least partly, due to release of lysosomal enzymes into the medium. A positive but slight correlation was found between extracellular lysosomal activity and four parameters of lung lesion (lung index, bronchoalveolar fluid total (BALF) protein concentration, BALF LDH and BALF alkaline phosphatase activities). All the above findings suggest that the AM release of lysosomal enzymes during HP is a factor involved, although possibly not the only one, in the pulmonary lesions appearing in this disease. 相似文献