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311.
The multimodal strategy incorporating T1-weighted magnetic resonance imaging (MRI) and near-infrared (NIR) fluorescence imaging can complement their strengths to provide images with high sensitivity and spatial resolution for noninvasively and dynamically monitoring endothelial progenitor cells (EPCs) in potential EPC-dominated therapies. Here we report the development of a protein-based imaging probe, bCD-PLL-Cy5.5 Conjugate 1, in which the bacterial cytosine deaminase (bCD) protein was modified with poly-l-lysine (PLL) that is labeled with imaging reporters, including T1-weighted MRI contrast chelator and NIR fluorophore. Conjugate 1 showed low cytotoxicity in EPCs isolated from the rabbit peripheral blood. The normalized cell viability was maintained above 90% after incubation for 1 to 5 days. Fluorescence microscopy of live cells indicated rapid cellular uptake of Conjugate 1 into EPCs in 15 minutes, and flow cytometry studies demonstrated the time-dependent internalization of Conjugate 1 with maximum uptake 48 hours after the treatment. MRI of phantoms demonstrated significant reduction of the T1 value of the EPC pellet that was pretreated with 2 μM of Conjugate 1 for 24 hours. Our preliminary data suggest that as a multimodal imaging contrast medium, Conjugate 1 offers a promising imaging probe for tracking the delivery and therapeutic response of EPCs in vivo. 相似文献
312.
Zeng N Li Y He L Xu X Galicia V Deng C Stiles BL 《Molecular cancer research : MCR》2011,9(12):1708-1717
The α-subunit of eukaryotic initiation factor 2 (eIF2α) is a key translation regulator that plays an important role in cellular stress responses. In the present study, we investigated how eIF2α phosphorylation can be regulated by a tumor suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10) and how such regulation is used by PTEN-deficient hepatocytes to adapt and cope with oxidative stress. We found that eIF2α was hyperphosphorylated when Pten was deleted, and this process was AKT dependent. Consistent with this finding, we found that the Pten-null cells developed resistance to oxidative glutamate and H(2)O(2)-induced cellular toxicity. We showed that the messenger level of CReP (constitutive repressor of eIF2α phosphorylation), a constitutive phosphatase of eIF2α, was downregulated in Pten-null hepatocytes, providing a possible mechanism through which PTEN/AKT pathway regulates eIF2α phosphorylation. Ectopic expression of CReP restored the sensitivity of the Pten mutant hepatocytes to oxidative stress, confirming the functional significance of the downregulated CReP and upregulated phospho-eIF2α in the resistance of Pten mutant hepatocytes to cellular stress. In summary, our study suggested a novel role of PTEN in regulating stress response through modulating the CReP/eIF2α pathway. 相似文献
313.
Fei Gao Shi Fang Ding Mei Ni Chun Xi Liu Cheng Zhang Yun Zhang 《Journal of cellular and molecular medicine》2011,15(3):602-611
To test the hypothesis that combinatorial interference of toll-like receptor 2 (TLR2) and TLR4 is superior to isolated interference of TLR2 or TLR4 in stabilizing atherosclerotic plaques, lentiviruses carrying small interfering RNA of TLR2 or TLR4 were constructed and proved efficacious for knocking down mRNA and protein expression of TLR2 or TLR4 significantly in vitro. One hundred and fifty apolipoprotein E−/− mice fed a high-fat diet were divided into the control, mock, TLR2i, TLR4i and TLR2 + 4i subgroups and a constrictive collar was placed around carotid artery of these mice to induce plaque formation. TLR2i and TLR4i viral suspension was transfected into carotid plaques, respectively, in TLR2i and TLR4i subgroups, or in combination in TLR2 + 4i subgroup. Four weeks after lentivirus transfection, mRNA and protein expression of TLR2 or TLR4 was attenuated markedly in carotid plaques, leading to reduced local inflammatory cytokine expression and plaque content of lipid and macrophages, increased plaque content of collagen and lowered plaque vulnerability index. Factorial ANOVA analysis revealed that there was a synergistic effect between TLR4i and TLR2i in stabilizing plaques. In conclusion, combinatorial interference of TLR2 and TLR4 reduces local inflammation and stabilizes plaques more effectively than interference of TLR2 or TLR4 alone. 相似文献
314.
Digital image analysis of expansion growth of cultured cotton ovules with fibers and their responses to ABA 总被引:1,自引:0,他引:1
Ling Fan Meng Lü Zhi-Yong Ni Wen-Ran Hu Juan Wang 《In vitro cellular & developmental biology. Plant》2011,47(3):369-374
Cotton ovule cultures have obvious advantages over whole plants when experimental protocols call for inhibitors, radio-labeled
precursors or controlled environmental conditions to be tested. The responses of ovule expansion growth and attached fiber
elongation to external factors require accurate measurement techniques. This paper presents a new method for digital image
analysis of the growth area of cotton ovules with fibers at high resolution. The method was characterized under constant conditions
and during dynamic responses to different levels of ABA (abscisic acid) treatment. The growth area was treated as area occupied
within the outline of the Petri dish image of the growing ovule with fibers. Growth area increase showed the same trends as
fiber length increase and was significantly correlated with the fiber length increase under different levels of ABA treatment
(r
2 = 0.97). This new analysis method provides a simple, noninvasive, and more accurate approach for growth analysis in the cotton
ovule culture system. Using this method, the effects of ABA on expansion growth of ovule with fibers were characterized. 相似文献
315.
Măruţescu L Niţulescu MG Bucur M Diţu LM Mihăescu G Lazăr V Sesan T 《Roumanian archives of microbiology and immunology》2011,70(2):49-53
A series of N-(1-methyl-1 Hpyrazole-4-carbonyl)-thiourea derivatives were assessed for their in vitro antimicrobial and anti-pathogenic activity against twenty-two strains of Erwinia amylovora isolated from different regions in Romania. The compounds were solubilised in dimethylsulfoxide and screened for their in vitro antimicrobial activity. The qualitative screening of the susceptibility spectra of various strains to the compounds was performed by adapted diffusion techniques (distribution of the tested compound solution directly on the solid medium previously seeded with the bacterial inoculums). The quantitative assay of the minimal inhibitory concentration (MIC, microg/mL) was based on liquid medium two-fold microdilutions. The subinhibitory concentrations of the tested substances were investigated for their influence on biofilm development on inert substrata. The present study showed that six new thiourea compounds exhibited a low antibacterial activity (MIC values > 500 microg/ml), but the subinhibitory concentrations inhibited the biofilm development on inert substrata. Thus, these results could suggest the usefulness of the tested compounds as control agents for preventing the first stage (colonization) of the infection with the fire blight pathogen. 相似文献
316.
Li LA Wu ZW Yang XJ Ni YD Parvizi N Zhao RQ 《In vitro cellular & developmental biology. Animal》2011,47(7):425-430
The present in vitro experiment was designed to test whether 48 h of pretreatment with glucocorticoids, cortisol, or dexamethasone
(DEX), would affect basal and corticotrophin (ACTH) stimulated (24 h) cortisol secretion from primary cultures of pig adrenocortical
cells. Cells were divided into six groups: control pretreatment with or without ACTH challenge, cortisol pretreatment with
or without ACTH challenge, and DEX pretreatment with or without ACTH. The culture medium and cells were collected at the end
of treatment. Cortisol concentration in medium was measured by radioimmunoassay, and protein content of glucocorticoid receptor
(GR) and key regulatory factors for steroidogenesis, including melanocortin type 2 receptor (MC2R), steroidogenic acute regulatory
protein (StAR) and cholesterol side-chain cleavage cytochrome P450 (P450scc), were detected by Western blot analysis. The
results showed that glucocorticoid pretreatment did not affect cortisol secretion under basal condition without ACTH challenge,
but significantly enhanced ACTH-stimulated cortisol secretion. Furthermore, the protein content of GR, MC2R, StAR, and P450scc
was all increased in groups pretreated with glucocorticoids. These results indicate that adrenocortical cells pretreated with
glucocorticoids display higher steroidogenic capacity under ACTH challenge, through the upregulation of GR and other steroidogenic
regulatory factors. 相似文献
317.
Huang N Lian JF Huo JH Liu LY Ni L Yang X Zhou JQ Li ZF Song TS Huang C 《Cell biology international》2011,35(3):193-199
EGFP (enhanced green fluorescent protein) tagged to either the N (amino)-terminus [EGFP/hERG (human ether-a-go-go-related gene)] or C (carboxyl)-terminus (hERG/EGFP) of hERG channel is used to study mutant channel protein trafficking for several years. However, it has been reported that the process can alter hERG channel properties. The aim of the study was to determine whether EGFP tagged to N-terminus of hERG channels would alter the cellular localizations and the electrophysiological properties of hERG channels compared with untagged hERG channels. The hERG channels tagged with or without EGFP were transiently expressed in HEK (human embryonic kidney) 293 cells using a lipofectamine method. HEK 293 cells expressing pCDNA3-hERG or pEGFP-hERG were double immunolabelled with anti-hERG and anti-calnexin (an ER marker protein) followed with FITC- and TRITC (tetramethylrhodamine β-isothiocyanate)-labelled secondary antibodies, respectively. Confocal laser scanning microscope was used to observe the cellular localization of EGFP-tagged hERG channels and untagged hERG channels. Patch-clamp technique was used to record whole cell currents. We found that the EGFP/hERG fusion protein and untagged hERG channels were both expressed not only on the cell surface membrane but also in the cytoplasm of HEK293 cells. The EGFP/hERG appeared to influence the hERG channel gating properties, including reduction of the peak tail current density, more rapid inactivation process, faster recovery from inactivation and faster deactivation kinetics compared with untagged hERG channels. Our results suggest that the EGFP/hERG channel alter the electrophysiological properties of hERG channel, but it does not seem to alter the cellular location of hERG channels. Thus, EGFP tagging to N-terminus might be used for research of subcellular location of hERG channels but not for the channel electrophysiological properties. 相似文献
318.
Shen L Xiao M Kong F Brown M Sun J Kong Q Cha J Xiang H Xu H Jin H Wei L Ni X 《Journal of applied microbiology》2011,111(3):625-630
Aims: For the rapid detection of Laribacter hongkongensis, which is associated with human community‐acquired gastroenteritis and traveller’s diarrhoea, we developed a duplex species‐specific PCR assay. Methods and Results: Full‐length of the 16S–23S rRNA intergenic spacer region (ISR) sequences of 52 L. hongkongensis isolates were obtained by PCR‐based sequencing. Two species‐specific primer pairs targeting 16S rRNA gene and ISR were designed for duplex PCR detection of L. hongkongensis. The L. hongkongensis species‐specific duplex PCR assay showed 100% specificity, and the minimum detectable level was 2·1 × 10?2 ng μl?1 genomic DNA which corresponds to 5000 CFU ml?1. Conclusions: The high specificity and sensitivity of the assay make it suitable for rapid detection of L. hongkongensis. Significance and Impact of the Study: This species‐specific duplex PCR method provides a rapid, simple, and reliable alternative to conventional methods to identify L. hongkongensis and may have applications in both clinical and environmental microbiology. 相似文献
319.
Aims: To evaluate the frequency of the aerolysin (aerA), cytotoxic enterotoxin (alt) and serine protease (ahp) genes in Aeromonas hydrophila isolates from different sources, and to determine the relationship between the presence of these genes and virulence of A. hydrophila in zebrafish. Methods and Results: Aeromonas hydrophila isolates from clinical cases (n = 40), from healthy fish (n = 22) and from water environment (n = 21) were analysed with respect to the prevalence of aerA, alt and ahp genes by PCR assay. These virulence factors occur among clinical isolates as well as among isolates from healthy fish and water environment. The majority (97·6%) of the strains examined carried one or more virulence genes. The isolates were divided into seven genetic profiles on the basis of PCR result: aerA+alt+ahp+ (62·7%), aerA+alt+ahp? (13·3%), aerA+alt?ahp+ (10·8%), aerA?alt+ahp+ (4·8%), aerA?alt?ahp+ (3·6%), aerA+alt?ahp? (2·4%) and aerA?alt?ahp? (2·4%). A higher frequency of genetic group aerA+alt+ahp+ was determined in the isolates from diseased animals compared to those from healthy fish or water environments. Virulence properties of 26 representative strains belonging to the seven genetic profiles were further characterized. Results demonstrated that as the present of virulence genes increased, the proteolytic, haemolytic and cytotoxic activities of extracellular products also increased. And the 50% lethal doses (LD50s) of aerA+alt+ahp+ isolates (<105) in zebrafish were lower when compared with the strains expressing one or combinations of two virulence genes (>106). Conclusions: Virulence properties of A. hydrophila correlated well with the presence of virulence genes tested. aerA+alt+ahp+ was more frequent virulence genotype in A. hydrophila isolates from clinical diseases than from healthy fish and water environment, and the aerA+alt+ahp+ isolates were more virulent to zebrafish compared to the other six genetic profiles. Significant and Impact of the Study: The detection for aerA, alt and ahp can be used for virulence typing of A. hydrophila isolates. 相似文献
320.
Tang TT Zhu ZF Wang J Zhang WC Tu X Xiao H Du XL Xia JH Dong NG Su W Xia N Yan XX Nie SF Liu J Zhou SF Yao R Xie JJ Jevallee H Wang X Liao MY Shi GP Fu M Liao YH Cheng X 《PloS one》2011,6(9):e24272