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Plastid structure and carotenogenic gene expression in red- and white-fleshed loquat (Eriobotrya japonica) fruits 总被引:1,自引:0,他引:1
Fu X Kong W Peng G Zhou J Azam M Xu C Grierson D Chen K 《Journal of experimental botany》2012,63(1):341-354
Loquat (Eriobotrya japonica Lindl.) can be sorted into red- and white-fleshed cultivars. The flesh of Luoyangqing (LYQ, red-fleshed) appears red-orange because of a high content of carotenoids while the flesh of Baisha (BS, white-fleshed) appears ivory white due to a lack of carotenoid accumulation. The carotenoid content in the peel and flesh of LYQ was approximately 68 μg g(-1) and 13 μg g(-1) fresh weight (FW), respectively, and for BS 19 μg g(-1) and 0.27 μg g(-1) FW. The mRNA levels of 15 carotenogenesis-related genes were analysed during fruit development and ripening. After the breaker stage (S4), the mRNA levels of phytoene synthase 1 (PSY1) and chromoplast-specific lycopene β-cyclase (CYCB) were higher in the peel, and CYCB and β-carotene hydroxylase (BCH) mRNAs were higher in the flesh of LYQ, compared with BS. Plastid morphogenesis during fruit ripening was also studied. The ultrastructure of plastids in the peel of BS changed less than in LYQ during fruit development. Two different chromoplast shapes were observed in the cells of LYQ peel and flesh at the fully ripe stage. Carotenoids were incorporated in the globules in chromoplasts of LYQ and BS peel but were in a crystalline form in the chromoplasts of LYQ flesh. However, no chromoplast structure was found in the cells of fully ripe BS fruit flesh. The mRNA level of plastid lipid-associated protein (PAP) in the peel and flesh of LYQ was over five times higher than in BS peel and flesh. In conclusion, the lower carotenoid content in BS fruit was associated with the lower mRNA levels of PSY1, CYCB, and BCH; however, the failure to develop normal chromoplasts in BS flesh is the most convincing explanation for the lack of carotenoid accumulation. The expression of PAP was well correlated with chromoplast numbers and carotenoid accumulation, suggesting its possible role in chromoplast biogenesis or interconversion of loquat fruit. 相似文献
34.
Inhibition of CLIC4 enhances autophagy and triggers mitochondrial and ER stress-induced apoptosis in human glioma U251 cells under starvation 总被引:1,自引:0,他引:1
CLIC4/mtCLIC, a chloride intracellular channel protein, localizes to mitochondria, endoplasmic reticulum (ER), nucleus and cytoplasm, and participates in the apoptotic response to stress. Apoptosis and autophagy, the main types of the programmed cell death, seem interconnected under certain stress conditions. However, the role of CLIC4 in autophagy regulation has yet to be determined. In this study, we demonstrate upregulation and nuclear translocation of the CLIC4 protein following starvation in U251 cells. CLIC4 siRNA transfection enhanced autophagy with increased LC3-II protein and puncta accumulation in U251 cells under starvation conditions. In that condition, the interaction of the 14-3-3 epsilon isoform with CLIC4 was abolished and resulted in Beclin 1 overactivation, which further activated autophagy. Moreover, inhibiting the expression of CLIC4 triggered both mitochondrial apoptosis involved in Bax/Bcl-2 and cytochrome c release under starvation and endoplasmic reticulum stress-induced apoptosis with CHOP and caspase-4 upregulation. These results demonstrate that CLIC4 nuclear translocation is an integral part of the cellular response to starvation. Inhibiting the expression of CLIC4 enhances autophagy and contributes to mitochondrial and ER stress-induced apoptosis under starvation. 相似文献
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Translation initiation in many eukaryotic mRNAs is modulated by an interaction between the cap binding protein complex, bound to the 5' end of the mRNA, and the polyadenosine binding protein, bound to the 3'-terminal polyadenosine sequences. A few cellular and viral mRNAs, such as the hepatitis C virus (HCV) mRNA genome, lack 3'-terminal polyadenosine sequences. For such mRNAs, the question of whether their 3'-end sequences also regulate the initiation phase of protein synthesis via an interaction with their 5' ends has received intense scrutiny. For HCV mRNA, various experimental designs have led to conflicting interpretations, that the 3' end of the RNA can modulate translation initiation either in a positive or in a negative fashion. To examine the possibility of end-to-end communication in HCV in detail, mRNAs containing the HCV internal ribosome entry site linked to a luciferase coding region, followed by different 3' noncoding regions, were expressed in the cytoplasm of cultured cells by T7 RNA polymerase. The intracellular translation efficiencies, steady-state levels, stabilities, and 3'-end sequences of these chimeric RNAs were examined. It was found that the HCV 3' noncoding region modulates neither the translation nor the stability of the mRNAs. Thus, there is no detectable end-to-end communication in cytoplasmically expressed chimeric mRNAs containing the HCV noncoding regions. However, it remains an open question whether end-to-end communication occurs in full-length HCV mRNAs in the infected liver. 相似文献
37.
Association of neuregulin 1 with schizophrenia confirmed in a Scottish population 总被引:27,自引:0,他引:27 下载免费PDF全文
Stefansson H Sarginson J Kong A Yates P Steinthorsdottir V Gudfinnsson E Gunnarsdottir S Walker N Petursson H Crombie C Ingason A Gulcher JR Stefansson K St Clair D 《American journal of human genetics》2003,72(1):83-87
Recently, we identified neuregulin 1 (NRG1) as a susceptibility gene for schizophrenia in the Icelandic population, by a combined linkage and association approach. Here, we report the first study evaluating the relevance of NRG1 to schizophrenia in a population outside Iceland. Markers representing a core at-risk haplotype found in Icelanders at the 5' end of the NRG1 gene were genotyped in 609 unrelated Scottish patients and 618 unrelated Scottish control individuals. This haplotype consisted of five SNP markers and two microsatellites, which all appear to be in strong linkage disequilibrium. For the Scottish patients and control subjects, haplotype frequencies were estimated by maximum likelihood, using the expectation-maximization algorithm. The frequency of the seven-marker haplotype among the Scottish patients was significantly greater than that among the control subjects (10.2% vs. 5.9%, P=.00031). The estimated risk ratio was 1.8, which is in keeping with our report of unrelated Icelandic patients (2.1). Three of the seven markers in the haplotype gave single-point P values ranging from .000064 to .0021 for the allele contributing to the at-risk haplotype. This direct replication of haplotype association in a second population further implicates NRG1 as a factor that contributes to the etiology of schizophrenia. 相似文献
38.
Sharifah Nurain Syed Zanaruddin Pei San Yee Seen Yii Hor Yink Heay Kong Wan Maria Nabillah Wan Abd Ghani Wan Mahadzir Wan Mustafa Rosnah Binti Zain Stephen S. Prime Zainal Ariff Abd Rahman Sok-Ching Cheong 《PloS one》2013,8(11)
Objectives
The frequency of common oncogenic mutations and TP53 was determined in Asian oral squamous cell carcinoma (OSCC).Materials and Methods
The OncoCarta™ panel v1.0 assay was used to characterize oncogenic mutations. In addition, exons 4-11 of the TP53 gene were sequenced. Statistical analyses were conducted to identify associations between mutations and selected clinico-pathological characteristics and risk habits.Results
Oncogenic mutations were detected in PIK3CA (5.7%) and HRAS (2.4%). Mutations in TP53 were observed in 27.7% (31/112) of the OSCC specimens. Oncogenic mutations were found more frequently in non-smokers (p = 0.049) and TP53 truncating mutations were more common in patients with no risk habits (p = 0.019). Patients with mutations had worse overall survival compared to those with absence of mutations; and patients who harbored DNA binding domain (DBD) and L2/L3/LSH mutations showed a worse survival probability compared to those patients with wild type TP53. The majority of the oncogenic and TP53 mutations were G:C > A:T and A:T > G:C base transitions, regardless of the different risk habits.Conclusion
Hotspot oncogenic mutations which are frequently present in common solid tumors are exceedingly rare in OSCC. Despite differences in risk habit exposure, the mutation frequency of PIK3CA and HRAS in Asian OSCC were similar to that reported in OSCC among Caucasians, whereas TP53 mutations rates were significantly lower. The lack of actionable hotspot mutations argue strongly for the need to comprehensively characterize gene mutations associated with OSCC for the development of new diagnostic and therapeutic tools. 相似文献39.
40.
乳链球菌SB900胞壁肽聚糖的部分生物学活性 总被引:6,自引:0,他引:6
对乳链球菌(Streptococcuslactis)SB900胞壁肽聚糖(简称为LABPG)进行了分离纯化及化学成分分析,并测定了其部分生物学活性.结果表明,LABPG蛋白质含量为9.84%,NAG0.871μmol/mg,NAM1.14μmol/mg;氨基酸分析结果表明,Ala、Glu、Asp含量较高,分别为1.046、0.775、0.304μmol/mg。以小鼠为实验材料进行动物学实验,对LABPG的生物学活性测定结果表明,LANPG无毒、安全可靠;腹腔注射LABPG后,PMΦ数目增多,吞噬功能明显增强,血清溶菌酶活性增强;YC-花环实验表明,腹腔注射LABPG的小鼠PMΦ表面C3b受体活性增强,YC-花环形成率较高,统计学分析有显著差别。说明LABPG对于MΦ有一定的激活作用,可作为机体的免疫激活剂。 相似文献