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91.
The perivascular space of the rat pineal gland is known to contain phagocytic cells that are immunoreactive for leukocyte antigens, and thus they appear to belong to the macrophage/microglial cell line. These cells also contain MHC class II proteins. We investigated this cell type in the pineal gland of mice. Actively phagocytosing cells with a prominent lysosomal system were found in the pericapillary spaces of the mouse pineal gland following intravenous injection of horseradish peroxidase. The cells also exhibited strong acid phosphatase activity. Perivascular cells were immunopositive for MHC class II protein and for CD68, a marker of monocytes/phagocytes. This study verifies that perivascular phagocytes with antigen‐presenting properties are present in the mouse pineal gland. 相似文献
92.
Morten Skage Anders Hobæk Štĕpánka Ruthová Barbara Keller Adam Petrusek Jaromír Sed’a Piet Spaak 《Hydrobiologia》2007,594(1):19-32
A collaborative research effort was undertaken to evaluate the robustness of a recently developed genetic tool for species
identification of members in the morphologically variable Daphnia longispina species complex. This genetic method, based on restriction fragment length polymorphism (RFLP) of the internal transcribed
spacer region (ITS) of nuclear ribosomal DNA (rDNA) with restriction enzymes Mwo I and Sau96 I [Billiones et al., 2004. Hydrobiologia 526: 43–53], was applied to many different European populations. Results were
compared with two or more independently obtained characters (morphology, allozymes, mitochondrial DNA (mtDNA), or cloned rDNA-ITS
sequences). Individuals of most taxa were readily identified, but unexpected ITS-RFLP patterns were found in many individuals
indicated by other markers to be D. galeata or one of its hybrids. Among 43 investigated D. galeata populations (902 specimen analysed by ITS-RFLP), deviant RFLP fragment patterns occurred in 26 (i.e., more than half) of
the populations. The deviant patterns could be attributed to the loss of one single restriction site in the ITS2 region. This
loss made the distinction of D. galeata from other species unreliable, and F1 hybrids could not be identified. Future users should be aware of this shortcoming of
the Billions et al. [2004. Hydrobiologia 526: 43–53] protocol. As a solution to this problem, we present an improved genetic
identification protocol based on a simple double digestion of the rDNA-ITS region with the restriction enzymes BsrB I and EagI. Sequence analyses of rDNA-ITS clones and preliminary testing indicate that the new protocol is unaffected by the rDNA variation
which troubled the Mwo I/Sau96 I protocol. Further, the new protocol identifies all European species of the D. longispina complex, as well as their F1 hybrids. However, a wider screening is required to verify its general utility for all species,
since yet unknown variation may occur.
Guest editor: Piet Spaak
Cladocera: Proceedings of the 7th International Symposium on Cladocera 相似文献
93.
Morten Gjermansen Martin Nilsson Liang Yang Tim Tolker‐Nielsen 《Molecular microbiology》2010,75(4):815-826
Pseudomonas putida OUS82 biofilm dispersal was previously shown to be dependent on the gene PP0164 (here designated lapG). Sequence and structural analysis has suggested that the LapG geneproduct belongs to a family of cysteine proteinases that function in the modification of bacterial surface proteins. We provide evidence that LapG is involved in P. putida OUS82 biofilm dispersal through modification of the outer membrane‐associated protein LapA. While the P. putida lapG mutant formed more biofilm than the wild‐type, P. putida lapA and P. putida lapAG mutants displayed decreased surface adhesion and were deficient in subsequent biofilm formation, suggesting that LapG affects LapA, and that the LapA protein functions both as a surface adhesin and as a biofilm matrix component. Lowering of the intracellular c‐di‐GMP level via induction of an EAL domain protein led to dispersal of P. putida wild‐type biofilm but did not disperse P. putida lapG biofilm, indicating that LapG exerts its activity on LapA in response to a decrease in the intracellular c‐di‐GMP level. In addition, evidence is provided that associated to LapA a cellulase‐degradable exopolysaccharide is part of the P. putida biofilm matrix. 相似文献
94.
Occurrence of Antimicrobial Resistance in Fish-Pathogenic and Environmental Bacteria Associated with Four Danish Rainbow Trout Farms 总被引:6,自引:2,他引:6 下载免费PDF全文
Anja S. Schmidt Morten S. Bruun Inger Dalsgaard Karl Pedersen Jens L. Larsen 《Applied microbiology》2000,66(11):4908-4915
Surveillance of bacterial susceptibility to five antimicrobial agents was performed during a 1-year period in and around four freshwater fish farms situated along a stream in western Denmark. Besides assessing the levels of antibiotic resistance among the culturable fraction of microorganisms in fish, water, and sediment samples, two major fish pathogens (88 Flavobacterium psychrophilum isolates and 134 Yersinia ruckeri isolates) and 313 motile Aeromonas isolates, representing a group of ubiquitous aquatic bacteria, were isolated from the same samples. MICs were obtained applying a standardized agar dilution method. A markedly decreased susceptibility of F. psychrophilum isolates to most antimicrobial agents presently available for use in Danish aquaculture was detected, while the collected Y. ruckeri isolates remained largely sensitive to all therapeutic substances. Comparing the inlet and outlet samples, the increase of the antibiotic-resistant proportions observed among the culturable microflora was more pronounced and statistically significant among the motile aeromonads. High levels of individual and multiple antimicrobial resistances were demonstrated within the collected flavobacteria and aeromonads, thus indicating a substantial impact of fish farming on several groups of bacteria associated with aquacultural environments. 相似文献
95.
Opticin, a small leucine rich repeat protein (SLRP) contributes to vitreoretinal adhesion. This study was conducted to investigate the effects of hypoxia and vascular endothelial growth factor (VEGF) on matrix metalloproteinase (MMP) mediated opticin production in retinal pigment epithelium (RPE) cells. Primary cultured human RPE cells were treated with hypoxia (low oxygen and cobalt chloride) or VEGF (0-100 ng/mL). The mRNA levels of opticin and the protein levels of intra and extracellular opticin in RPE cells were examined by RT-PCR and Western blot assay, respectively. Furthermore, the MMP activity was analyzed by zymography, and EDTA was used as an MMP inhibitor. Analysis of the effect of MMP-2 on opticin was performed by recombinant human (rh) MMP-2 stimulation in RPE cultures and by human vitreous sample digestion with activated rhMMP-2. Our results showed that opticin was expressed by primary cultured human RPE cells. Hypoxia and VEGF stimulation did not alter opticin mRNA and protein expression in RPE cells, but markedly decreased the protein levels of extracellular opticin following increased latent MMP-2 activity. The VEGF- and hypoxia induced opticin degradation in the culture medium was blocked by EDTA. Together, opticin levels in the culture medium were also reduced after rhMMP-2 treatment. In addition, opticin in human vitreous samples could be cleaved by rhMMP-2. These results reveal that VEGF and hypoxia could decrease opticin protein levels in the human RPE secretome, and that opticin may be an enzymatic substrate for MMP-2. 相似文献
96.
Background
The major histocompatibility complex (MHC) molecule plays a central role in controlling the adaptive immune response to infections. MHC class I molecules present peptides derived from intracellular proteins to cytotoxic T cells, whereas MHC class II molecules stimulate cellular and humoral immunity through presentation of extracellularly derived peptides to helper T cells. Identification of which peptides will bind a given MHC molecule is thus of great importance for the understanding of host-pathogen interactions, and large efforts have been placed in developing algorithms capable of predicting this binding event. 相似文献97.
Ilka Hoof Bjoern Peters John Sidney Lasse Eggers Pedersen Alessandro Sette Ole Lund Søren Buus Morten Nielsen 《Immunogenetics》2009,61(1):1-13
Binding of peptides to major histocompatibility complex (MHC) molecules is the single most selective step in the recognition
of pathogens by the cellular immune system. The human MHC genomic region (called HLA) is extremely polymorphic comprising
several thousand alleles, each encoding a distinct MHC molecule. The potentially unique specificity of the majority of HLA
alleles that have been identified to date remains uncharacterized. Likewise, only a limited number of chimpanzee and rhesus
macaque MHC class I molecules have been characterized experimentally. Here, we present NetMHCpan-2.0, a method that generates quantitative predictions of the affinity of any peptide–MHC class I interaction. NetMHCpan-2.0 has been trained on the hitherto largest set of quantitative MHC binding data available, covering HLA-A and HLA-B, as well
as chimpanzee, rhesus macaque, gorilla, and mouse MHC class I molecules. We show that the NetMHCpan-2.0 method can accurately predict binding to uncharacterized HLA molecules, including HLA-C and HLA-G. Moreover, NetMHCpan-2.0 is demonstrated to accurately predict peptide binding to chimpanzee and macaque MHC class I molecules. The power of NetMHCpan-2.0 to guide immunologists in interpreting cellular immune responses in large out-bred populations is demonstrated. Further,
we used NetMHCpan-2.0 to predict potential binding peptides for the pig MHC class I molecule SLA-1*0401. Ninety-three percent of the predicted
peptides were demonstrated to bind stronger than 500 nM. The high performance of NetMHCpan-2.0 for non-human primates documents the method’s ability to provide broad allelic coverage also beyond human MHC molecules.
The method is available at .
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
98.
Establishing effective DNA-based protocols for use on archival material fixed in formaldehyde (formalin) is a particularly challenging task. Formalin fixation induces cross-linking with nucleic acids and proteins, thereby reducing the amount and quality of the extracted DNA. Previous attempts have primarily focused on optimizing DNA extraction protocols. Here we focus on the use of enzymes capable of in vitro repair of DNA extracts prior to amplification of the nucleic acids by the polymerase chain reaction (PCR). The amplification success of mitochondrial DNA was greater using the repair enzyme assay (56%) than with the regular PCR assay (20%), and even more convincing results were obtained with the amplified nuclear ribosomal region (91% versus 21%). These results indicate that in vitro repair of DNA damage (depurinated sites, strand nicks and base modifications) increases the number of samples that amplify, amplify to a greater extent and amplify fewer ancillary bands and that DNA repair has been overlooked as a way of improving the efficiency of molecular methods used on formalin-fixed samples. Fidelity has not been specifically investigated, but preliminary results indicate that misincorporation is not a major problem. 相似文献
99.
A general feature of the demography of large ungulates is that many demographic traits are dependent on female body mass at
early ages. Thus, identifying the factors affecting body mass variation can give important mechanistic understanding of demographic
processes. Here we relate individual variation in autumn and winter body mass of moose calves living at low density on an
island in northern Norway to characteristics of their mother, and examine how these relationships are affected by annual variation
in population density and climate. Body mass increased with increasing age of their mother, was lower for calves born late
in the spring, decreased with litter size and was larger for males than for female calves. No residual effects of variation
in density and climate were present after controlling for annual variation in mother age and calving date. The annual variation
in adult female age structure and calving date explained a large part (71–75%) of the temporal variation in calf body mass.
These results support the hypotheses that (a) body mass of moose calves are affected by qualities associated with mother age
(e.g. body condition, calving date); and (b) populations living at low densities are partly buffered against temporal fluctuations
in the environment. 相似文献
100.
Ferreira C Silva S van Voorst F Aguiar C Kielland-Brandt MC Brandt A Lucas C 《FEMS yeast research》2006,6(7):1027-1038
Saccharomyces cerevisiae Gup1p and its homologue Gup2p, members of the superfamily of membrane-bound O-acyl transferases, were previously associated with glycerol-mediated salt-stress recovery and glycerol symporter activity. Several other phenotypes suggested Gup1p involvement in processes connected with cell structure organization and biogenesis. The gup1Delta mutant is also thermosensitive and exhibits an altered plasma membrane lipid composition. The present work shows that the thermosensitivity is independent of glycerol production and retention. Furthermore, the mutant grows poorly on salt, ethanol and weak carboxylic acids, suggestive of a malfunctioning membrane potential. Additionally, gup1Delta is sensitive to cell wall-perturbing agents, such as Calcofluor white, Zymolyase, lyticase and sodium dodecyl sulphate and exhibits a sedimentation/aggregation phenotype. Quantitative analysis of cell wall components yielded increased contents of chitin and beta-1,3-glucans and lower amounts of mannoproteins. Consistently, scanning electron microscopy showed a strikingly rough surface morphology of the mutant cells. These results suggest that the gup1Delta is affected in cell wall assembly and stability, although the Slt2p/MAP kinase from the PKC pathway was phosphorylated during hypo-osmotic shock to a normal extent. Results emphasize the pleiotropic nature of gup1Delta, and are consistent with a role of Gulp1p in connection with several pathways for cell maintenance and construction/remodelling. 相似文献