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91.
Belowground net primary productivity and biomass allocation of a grassland in Inner Mongolia is affected by grazing intensity 总被引:1,自引:0,他引:1
Ying Zhi Gao Marcus Giese Shan Lin Burkhard Sattelmacher Ying Zhao Holger Brueck 《Plant and Soil》2008,307(1-2):41-50
The root system of permanent grasslands is of outstanding importance for resource acquisition. Particularly under semi-arid conditions, the acquisition of water and nutrients is highly variable during the vegetation growth period and between years. Additionally, grazing is repeatedly disturbing the functional equilibrium between the root system and the transpiring leaf canopy. However, very few data is available considering grazing effects on belowground net primary productivity (BNPP) and root-shoot dry mass allocation in natural grassland systems. We hypothesise that grazing significantly reduces BNPP due to carbon reallocation to shoot growth. Root biomass and BNPP were estimated by soil coring in 2004, 2005 and 2006 and from ingrowth cores in 2005 and 2006 at one site which has been protected from grazing since 1979 (UG79), at one winter grazing (WG), and one heavily grazed (HG) site. BNPP was estimated from the summation of significant increments of total and live root biomass and from accumulated root biomass of ingrowth cores. Belowground biomass varied from 1,490–2,670 g m?2 and was significantly lower under heavy grazing than at site UG79. Root turnover varied from 0.23 to 0.33 year?1 and was not significantly different between sites. Heavy grazing significantly decreased live root biomass and BNPP compared to site UG79. Taking BNPP estimates from live root biomass dynamics and ingrowth cores as the most reliable values, the portion of dry mass allocated belowground relative to total net primary productivity (BNPP/NPP) varied between 0.50–0.66 and was reduced under heavy grazing in 2005, but not in 2006. The positive correlation between cumulative root length density of ingrowth cores and leaf dry matter suggests that the ingrowth core method is suitable for studying BNPP in this semi-arid steppe system. Grazing effects on BNPP and BNPP/NPP should be considered in regional carbon models and estimates of belowground nutrient cycling. 相似文献
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Christine Finnie Merethe Bagge Torben Steenholdt Ole Østergaard Kristian Sass Bak-Jensen Gunter Backes Anaïs Jensen Henriette Giese Jørgen Larsen Peter Roepstorff Birte Svensson 《Functional & integrative genomics》2009,9(1):135-143
Two-dimensional gel electrophoresis was used to screen spring barley cultivars for differences in seed protein profiles. In
parallel, 72 microsatellite (simple sequence repeat (SSR)) markers and 11 malting quality parameters were analysed for each
cultivar. Over 60 protein spots displayed cultivar variation, including peroxidases, serpins and proteins with unknown functions.
Cultivars were clustered based on the spot variation matrix. Cultivars with superior malting quality grouped together, indicating
malting quality to be more closely correlated with seed proteomes than with SSR profiles. Mass spectrometry showed that some
spot variations were caused by amino acid differences encoded by single nucleotide polymorphisms (SNPs). Coding SNPs were
validated by mass spectrometry, expressed sequence tag and 2D gel data. Coding SNPs can alter function of affected proteins
and may thus represent a link between cultivar traits, proteome and genome. Proteome analysis of doubled haploid lines derived
from a cross between a malting (Scarlett) and a feed cultivar (Meltan) enabled genetic localisation of protein phenotypes
represented by 48 spot variations, involving e.g. peroxidases, serpins, α-amylase/trypsin inhibitors, peroxiredoxin and a
small heat shock protein, in relation to markers on the chromosome map.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
95.
JF Yuan SJ Zhang O Jafer RA Furlong OE Chausiaux CA Sargent GH Zhang NA Affara 《BMC microbiology》2009,9(1):246
Background
Pseudorabies virus (PRV) is an alphaherpesviruses whose native host is pig. PRV infection mainly causes signs of central nervous system disorder in young pigs, and respiratory system diseases in the adult. 相似文献96.
97.
Sven R. Kantelhardt Wouter Caarls Anthony H. B. de Vries Guy M. Hagen Thomas M. Jovin Walter Schulz-Schaeffer Veit Rohde Alf Giese Donna J. Arndt-Jovin 《PloS one》2010,5(6)
Background
The current therapy of malignant gliomas is based on surgical resection, radio-chemotherapy and chemotherapy. Recent retrospective case-series have highlighted the significance of the extent of resection as a prognostic factor predicting the course of the disease. Complete resection in low-grade gliomas that show no MRI-enhanced images are especially difficult. The aim in this study was to develop a robust, specific, new fluorescent probe for glioma cells that is easy to apply to live tumor biopsies and could identify tumor cells from normal brain cells at all levels of magnification.Methodology/Principal Findings
In this investigation we employed brightly fluorescent, photostable quantum dots (QDs) to specifically target epidermal growth factor receptor (EGFR) that is upregulated in many gliomas. Living glioma and normal cells or tissue biopsies were incubated with QDs coupled to EGF and/or monoclonal antibodies against EGFR for 30 minutes, washed and imaged. The data include results from cell-culture, animal model and ex vivo human tumor biopsies of both low-grade and high-grade gliomas and show high probe specificity. Tumor cells could be visualized from the macroscopic to single cell level with contrast ratios as high as 1000: 1 compared to normal brain tissue.Conclusions/Significance
The ability of the targeted probes to clearly distinguish tumor cells in low-grade tumor biopsies, where no enhanced MRI image was obtained, demonstrates the great potential of the method. We propose that future application of specifically targeted fluorescent particles during surgery could allow intraoperative guidance for the removal of residual tumor cells from the resection cavity and thus increase patient survival. 相似文献98.
Nils Ole Schmidt Mateo Ziu Theresa Cargioli Manfred Westphal Alf Giese Peter M Black Rona S Carroll 《Translational oncology》2010,3(1):43-49
Thromboxane synthase (TXSA), an enzyme of the arachidonic acid metabolism, is upregulated in human glial tumors and is involved in glioma progression. Here, we analyzed the in vitro and in vivo effects of pharmacological inhibition of TXSA activity on human glioblastoma cells. Furegrelate, a specific inhibitor of TXSA, significantly inhibited tumor growth in an orthotopic glioblastoma model by inducing proapoptotic, antiproliferative, and antiangiogenic effects. Inhibition of TXSA induced a proapoptotic disposition of glioma cells and increased the sensitivity to the chemotherapeutic agent 1,3-bis(2-chloroethyl)-1-nitrosourea, significantly prolonging the survival time of intracerebral glioma-bearing mice. Our data demonstrate that the targeted inhibition of TXSA activity improves the efficiency of conventional alkylation chemotherapy in vivo. Our study supports the role of TXSA activity for the progression of malignant glioma and the potential utility of its therapeutic modulation for glioma treatment. 相似文献
99.
Melo FT Giese EG Furtado AP Soares MJ Gonçalves EC Vallinoto AC Santos JN 《Memórias do Instituto Oswaldo Cruz》2011,106(6):670-677
The family Nematotaeniidae, tapeworms commonly found in the small intestines of amphibians and reptiles, includes 27 recognised species distributed among four genera: Bitegmen Jones, Cylindrotaenia Jewell, Distoichometra Dickey and Nematotaenia Lühe. The taxonomy of these cestodes is poorly defined, due in part to the difficulties of observing many anatomical traits. This study presents and describes a new genus and species of nematotaeniid parasite found in cane toads (Rhinella marina) from eastern Brazilian Amazonia. The cestodes were collected during the necropsy of 20 hosts captured in the urban area of Belém, Pará. The specimens were fixed and processed for light microscopy, scanning electron microscopy (SEM) and three-dimensional (3D) reconstruction. Samples were also collected for molecular analyses. The specimens presented a cylindrical body, two testes and paruterine organs. However, they could not be allocated to any of the four existing nematotaeniid genera due to the presence of two each of dorsal compact medullary testes, cirri, cirrus pouches, genital pores, ovaries and vitelline glands per mature segment. Lanfrediella amphicirrus gen. nov. sp. nov. is the first nematotaeniid studied using Historesin analysis, SEM and 3D reconstruction, and it is the second taxon for which molecular data have been deposited in GenBank. 相似文献
100.
Weider K Bergmann M Giese S Guillou F Failing K Brehm R 《Differentiation; research in biological diversity》2011,82(1):38-49
Histological analysis revealed that Sertoli cell specific knockout of the predominant testicular gap junction protein connexin 43 results in a spermatogenic arrest at the level of spermatogonia or Sertoli cell-only syndrome, intratubular cell clusters and still proliferating adult Sertoli cells, implying an important role for connexin 43 in the Sertoli and germ cell development. This study aimed to determine the (1) Sertoli cell maturation state, (2) time of occurrence and (3) composition, differentiation and fate of clustered cells in knockout mice. Using immunohistochemistry connexin 43 deficient Sertoli cells showed an accurate start of the mature markers androgen receptor and GATA-1 during puberty and a vimentin expression from neonatal to adult. Expression of anti-Muellerian hormone, as a marker of Sertoli cell immaturity, was finally down-regulated during puberty, but its disappearance was delayed. This observed extended anti-Müllerian hormone synthesis during puberty was confirmed by western blot and Real-Time PCR and suggests a partial alteration in the Sertoli cell differentiation program. Additionally, Sertoli cells of adult knockouts showed a permanent and uniform expression of GATA-1 at protein and mRNA level, maybe caused by the lack of maturing germ cells and missing negative feedback signals. At ultrastructural level, basally located adult Sertoli cells obtained their mature appearance, demonstrated by the tripartite nucleolus as a typical feature of differentiated Sertoli cells. Intratubular clustered cells were mainly formed by abnormal Sertoli cells and single attached apoptotic germ cells, verified by immunohistochemistry, TUNEL staining and transmission electron microscopy. Clusters first appeared during puberty and became more numerous in adulthood with increasing cell numbers per cluster suggesting an age-related process. In conclusion, adult connexin 43 deficient Sertoli cells seem to proliferate while maintaining expression of mature markers and their adult morphology, indicating a unique and abnormal intermediate phenotype with characteristics common to both undifferentiated and differentiated Sertoli cells. 相似文献