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81.
Six species of mushrooms allied to the Family Sclerodermataceae, Lycoperdaceae and Geastraceae have been described for the first time from Azad Jammu and Kashmir. These are Scleroderma aurantium, Calvatia verrucosia sp. nov., Lycoperdon pedicellaton sp. nov. L. sphaericon sp. nov., L. echinulaton sp. nov., and Geastrum heptaplex sp. nov.  相似文献   
82.
Cattle are reared in diverse environments and collecting phenotypic body temperature (BT) measurements to characterize BT variation across diverse environments is difficult and expensive. To better understand the genetic basis of BT regulation, a genome-wide association study was conducted utilizing crossbred steers and heifers totaling 239 animals of unknown pedigree and breed fraction. During predicted extreme heat and cold stress events, hourly tympanic and vaginal BT devices were placed in steers and heifers, respectively. Individuals were genotyped with the BovineSNP50K_v2 assay and data analyzed using Bayesian models for area under the curve (AUC), a measure of BT over time, using hourly BT observations summed across 5-days (AUC summer 5-day (AUCS5D) and AUC winter 5-day (AUCW5D)). Posterior heritability estimates were moderate to high and were estimated to be 0.68 and 0.21 for AUCS5D and AUCW5D, respectively. Moderately positive correlations between direct genomic values for AUCS5D and AUCW5D (0.40) were found, although a small percentage of the top 5 % 1-Mb windows were in common. Different sets of genes were associated with BT during winter and summer, thus simultaneous selection for animals tolerant to both heat and cold appears possible.  相似文献   
83.

Background

The identification of genetic markers associated with complex traits that are expensive to record such as feed intake or feed efficiency would allow these traits to be included in selection programs. To identify large-effect QTL, we performed a series of genome-wide association studies and functional analyses using 50 K and 770 K SNP genotypes scored in 5,133 animals from 4 independent beef cattle populations (Cycle VII, Angus, Hereford and Simmental × Angus) with phenotypes for average daily gain, dry matter intake, metabolic mid-test body weight and residual feed intake.

Results

A total of 5, 6, 11 and 10 significant QTL (defined as 1-Mb genome windows with Bonferroni-corrected P-value <0.05) were identified for average daily gain, dry matter intake, metabolic mid-test body weight and residual feed intake, respectively. The identified QTL were population-specific and had little overlap across the 4 populations. The pleiotropic or closely linked QTL on BTA 7 at 23 Mb identified in the Angus population harbours a promising candidate gene ACSL6 (acyl-CoA synthetase long-chain family member 6), and was the largest effect QTL associated with dry matter intake and mid-test body weight explaining 10.39% and 14.25% of the additive genetic variance, respectively. Pleiotropic or closely linked QTL associated with average daily gain and mid-test body weight were detected on BTA 6 at 38 Mb and BTA 7 at 93 Mb confirming previous reports. No QTL for residual feed intake explained more than 2.5% of the additive genetic variance in any population. Marker-based estimates of heritability ranged from 0.21 to 0.49 for residual feed intake across the 4 populations.

Conclusions

This GWAS study, which is the largest performed for feed efficiency and its component traits in beef cattle to date, identified several large-effect QTL that cumulatively explained a significant percentage of additive genetic variance within each population. Differences in the QTL identified among the different populations may be due to differences in power to detect QTL, environmental variation, or differences in the genetic architecture of trait variation among breeds. These results enhance our understanding of the biology of growth, feed intake and utilisation in beef cattle.  相似文献   
84.

Introduction

The majority of the genetic variance of systemic lupus erythematosus (SLE) remains unexplained by the common disease-common variant hypothesis. Rare variants, which are not detectable by genome-wide association studies because of their low frequencies, are predicted to explain part of this ”missing heritability.” However, recent studies identifying rare variants within known disease-susceptibility loci have failed to show genetic associations because of their extremely low frequencies, leading to the questioning of the contribution of rare variants to disease susceptibility. A common (minor allele frequency = 17.4% in cases) nonsynonymous coding variant rs1143679 (R77H) in ITGAM (CD11b), which forms half of the heterodimeric integrin receptor, complement receptor 3 (CR3), is robustly associated with SLE and has been shown to impair CR3-mediated phagocytosis.

Methods

We resequenced ITGAM in 73 SLE cases and identified two previously unidentified, case-specific nonsynonymous variants, F941V and G1145S. Both variants were genotyped in 2,107 and 949 additional SLE cases, respectively, to estimate their frequencies in a disease population. An in vitro model was used to assess the impact of F941V and G1145S, together with two nonsynonymous ITGAM polymorphisms, A858V (rs1143683) and M441T (rs11861251), on CR3-mediated phagocytosis. A paired two-tailed t test was used to compare the phagocytic capabilities of each variant with that of wild-type CR3.

Results

Both rare variants, F941V and G1145S, significantly impair CR3-mediated phagocytosis in an in vitro model (61% reduction, P = 0.006; 26% reduction, P = 0.0232). However, neither of the common variants, M441T and A858V, had an effect on phagocytosis. Neither rare variant was observed again in the genotyping of additional SLE cases, suggesting that there frequencies are extremely low.

Conclusions

Our results add further evidence to the functional importance of ITGAM in SLE pathogenesis through impaired phagocytosis. Additionally, this study provides a new example of the identification of rare variants in common-allele-associated loci, which, because of their extremely low frequencies, are not statistically associated. However, the demonstration of their functional effects adds support to their contribution to disease risk, and questions the current notion of dismissing the contribution of very rare variants on purely statistical analyses.  相似文献   
85.
A genome-wide association study in Japan identified the C-C chemokine receptor type 6 gene (CCR6) as associated with rheumatoid arthritis (RA). This finding has not been validated in other Asian populations. A case-control study involving 996 subjects, comprising 440 controls and 556 RA patients, was done to determine their anticyclic citrullinated peptide (anti-CCP) antibody status and CCR6 polymorphism (rs3093024) genotype. Three hundred eighty-seven patients were anti-CCP positive and 153 anti-CCP negative. Logistic regression showed that allele A was likely to increase the risk of developing RA among females via a recessive model (odds ratio [OR]=1.55, 95% confidence interval [CI]=1.01, 2.39), whereas the risk effect appeared to be reduced among males via an additive model (OR=0.60, 95% CI=0.42, 0.85). Considering only subjects who are anti-CCP positive, allele A increased RA risk among females via a recessive model (OR=1.68, 95% CI=1.07, 2.64) but decreased the risk among males via an additive model (OR=0.59, 95% CI=0.39, 0.89). We showed that CCR6 polymorphism was a risk factor among females but a protective factor among males. Functional studies are warranted to unravel the pathophysiological relevance of the gene variant and other linked variants with RA.  相似文献   
86.
87.
S Rasmussen  RA Dixon 《The Plant cell》1999,11(8):1537-1552
3H-l-Phenylalanine is incorporated into a range of phenylpropanoid compounds when fed to tobacco cell cultures. A significant proportion of (3)H-trans-cinnamic acid formed from (3)H-l-phenylalanine did not equilibrate with exogenous trans-cinnamic acid and therefore may be rapidly channeled through the cinnamate 4-hydroxylase (C4H) reaction to 4-coumaric acid. Such compartmentalization of trans-cinnamic acid was not observed after elicitation or in cell cultures constitutively expressing a bean phenylalanine ammonia-lyase (PAL) transgene. Channeling between PAL and C4H was confirmed in vitro in isolated microsomes from tobacco stems or cell suspension cultures. This channeling was strongly reduced in microsomes from stems or cell cultures of transgenic PAL-overexpressing plants or after elicitation of wild-type cell cultures. Protein gel blot analysis showed that tobacco PAL1 and bean PAL were localized in both soluble and microsomal fractions, whereas tobacco PAL2 was found only in the soluble fraction. We propose that metabolic channeling of trans-cinnamic acid requires the close association of specific forms of PAL with C4H on microsomal membranes.  相似文献   
88.
A key role of chromatin kinases is to phosphorylate histone tails during mitosis to spatiotemporally regulate cell division. Vaccinia-related kinase 1 (VRK1) is a serine–threonine kinase that phosphorylates histone H3 threonine 3 (H3T3) along with other chromatin-based targets. While structural studies have defined how several classes of histone-modifying enzymes bind to and function on nucleosomes, the mechanism of chromatin engagement by kinases is largely unclear. Here, we paired cryo-electron microscopy with biochemical and cellular assays to demonstrate that VRK1 interacts with both linker DNA and the nucleosome acidic patch to phosphorylate H3T3. Acidic patch binding by VRK1 is mediated by an arginine-rich flexible C-terminal tail. Homozygous missense and nonsense mutations of this acidic patch recognition motif in VRK1 are causative in rare adult-onset distal spinal muscular atrophy. We show that these VRK1 mutations interfere with nucleosome acidic patch binding, leading to mislocalization of VRK1 during mitosis, thus providing a potential new molecular mechanism for pathogenesis.  相似文献   
89.
Cholera toxin (CT) activates expression of two immediate-early response genes (JE and TIS10) in quiescent BALB/c 3T3 cells. Increases in cyclic AMP (cAMP) levels in response to CT are likely responsible for the induction of TIS10 gene expression, since treatment with 8-Br-cAMP and increasing the intracellular levels of cAMP by treatment with forskolin induce TIS10 gene expression. In contrast, neither forskolin nor 8-Br-cAMP induces JE gene expression. 3-Isobutyl-1-methylxanthine, which stabilizes intracellular cAMP, potentiates CT-induced TIS10 gene expression but has no effect on CT-induced JE gene expression. Thus, induction of JE by CT is independent of the cAMP produced in response to CT. Induction of JE by CT does not require protein kinase C (PKC), since depleting cells of PKC activity has no effect on the induction of JE by CT. CT-induced expression of JE can be distinguished from CT-induced TIS10 gene expression by using protein kinase inhibitors and inhibitors of arachidonic acid metabolism, further suggesting distinct signaling pathways for CT-induced JE and TIS10 gene expression. Thus, induction of JE gene expression by CT results from the activation of an intracellular signaling pathway that is independent of cAMP production. This pathway is independent of PKC activity and uniquely sensitive to inhibitors of protein kinases and arachidonic acid metabolism.  相似文献   
90.
Three roselle, Hibiscus sabdariffa L. varieties (Sudani, Masri and White) were cultivated at three different locations to recognize the transportation ability of roselle cultivation from the narrow old valley land to broad new land in Egypt. Qena as origin in situ old land, El-Kanater as ex situ old land and Nubaria as ex situ new land were the considered locations. Six growth quantitative characters and bolls infestation by spiny bollworm, Earias insulana were evaluated. Growth characters of roselle plants were affected significantly by either variety or location. Qena region was more suitable for roselle plant growth as judged with plant height, number of branches, number of fruits and sepals dry weight, followed by Nubaria followed by El-Kanater. Whereas, plants grown at Nubaria produced more fresh sepals weight than Qena or El-Kanater grown plants. As for Sudani, Nubaria exhibited the tallest plants, with the highest number of fruits and the heaviest fresh sepals as compared with the corresponding plants in Qena or El-Kanater. Values of broad sense heritability were highest for all characters in Qena. While the number of fruits per plant had the highest heritability in all locations. Dry sepals yield had highly significant correlation with all studied characters except percentage of water loss in Qena and Nubaria. Path coefficient analysis confirmed that fresh sepals yield had the highest direct and indirect effects on dried sepals yield. Chemical constituents responsible to sepal quality tended to produce significant variations due to the changes in varieties or locations. The highest levels of anthocyanins and sugars were achieved by Sudani variety, but the highest levels of free amino acids and total soluble solids were recorded for Masri variety. Moreover, Nubaria region was the most favourable for the accumulation of more anthocyanins in the sepals of all varieties followed by Qena. Plants grown at Qena produced sepals with the highest levels of sugars, free amino acids, organic acids and total soluble solids, followed by Nubaria followed by El-Kanater plants. Infestation with spiny bollworm Earias insulana was increased from Sudani up to Masri up to White varieties. Plants grown at Nubaria had the lowest number of attacks by bolls in all varieties, followed by those at El-Kanater followed by Qena plants. Spiny bollworm infestation was positively correlated with the number of branches and dry sepals weight, but negatively correlated with sepal moisture loss and anthocyanin contents. These findings clearly indicated that the Nubaria region was considered as a promising reclaimed area suitable for roselle cultivation, especially for Sudani, the most economic variety.  相似文献   
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