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991.
Zhao X Chao Y Chen P Liu D Su P Sun J Cui X Tang Y 《Journal of physiology and biochemistry》2012,68(1):129-139
The 26S proteasome is a key component of the ubiquitin-proteasome system, a process responsible for the majority of cellular
protein degradation. The function of the proteasomal ubiquitin receptor hRpn13, a component of the 26S proteasome, is not
completely understood. To investigate the role of hRpn13 in the ubiquitin-proteasome system in osteoblasts, the effects of
suppressing and overexpressing the hRpn13 gene on proliferation, differentiation, and function of human osteoblast-like MG63
cells were examined. After knockdown of hRpn13 by small interfering RNA, changes in osteoblast proliferation were evaluated
by methyl-thiazolyl-tetrazolium assay. There was an increase in markers for osteoblast proliferation, specifically alkaline
phosphatase activity, and elevated protein levels of osteocalcin, proliferating cell nuclear antigen (PCNA), and ubiquitin.
Furthermore, hRpn13 knockdown also resulted in a decrease in the ratio between the gene expressions of RANKL and OPG, key
players in the pathogenesis of bone diseases that influence the normal balance between bone formation and resorption. In contrast,
overexpression of hRpn13 inhibited the proliferation of MG63 cells, and decreased alkaline phosphatase activity as well as
protein levels of osteocalcin, PCNA, and ubiquitin while the ratio of RANKL to OPG expression increased. To confirm the function
of hRpn13 in the ubiquitin-proteasome pathway, osteoblast proliferation enhancement and ubiquitin accumulation after hRpn2
knockdown was assessed. The results suggest that overexpression of hRpn13 negatively influences proliferation and osteogenic
differentiation in MG63 cells. The evidence implies that hRpn13 modulates the influence of osteoblasts on osteoclasts by controlling
the stability of regulatory proteins in osteoblasts. In summary, overexpression of hRpn13 promoted the activity of the ubiquitin-proteasome
system. 相似文献
992.
N Mao Y Ji Z Xie H Wang H Wang J An X Zhang Y Zhang Z Zhu A Cui S Xu K Shen C Liu W Yang W Xu 《PloS one》2012,7(8):e43893
The relevance of human parainfluenza viruses (HPIVs) to the epidemiology of acute respiratory infections (ARI) in China is unclear. From May 2008 to September 2010, 443 nasopharyngeal aspirates (NPAs) from hospitalized pediatric patients (age from 1 to 93 months) in Beijing were collected and screened for HPIVs and other common respiratory viruses by real-time RT-PCR. Sixty-two of 443 samples were positive for HPIVs with 4 positive for HPIV-2 and 58 positive for HPIV-3, indicating that HPIV-3 was the predominant virus present during the study period. A phylogenetic tree based on all the available HN (hemagglutinin-neuraminidase) sequences of HPIV-3 indicated that three distinct clusters (A,B, and C) were circulating with some temporal and regional clustering. Cluster C was further divided into sub-clusters, C1, C2, C3 and C4. HPIV-3 from Beijing isolates belonged to sub-cluster C3, and were grouped with the isolates from two Provinces of China and the neighboring country of Japan. Genetic analysis based on entire HN gene revealed that the HPIV-3 isolates from Beijing were highly similar with 97.2%-100% identity at the nucleotide level and these could be divided into two closely related lineages, C3a and C3b. These findings suggested that there was co-circulation of multiple lineages of HPIV-3 in the Beijing region during the study period. This is the first study to describe the epidemiology and molecular characterization of HPIVs in China. 相似文献
993.
A novel 'white' laccase was purified from the deuteromycete fungus, Myrothecium verrucaria NF-05, which was a high laccase-producing strain (40.2 U·ml(-1) on the thirteenth day during fermentation). SDS-PAGE and native-PAGE revealed a single band with laccase activity corresponding to a molecular weight of approximately 66 kDa. The enzyme had three copper and one iron atoms per protein molecule determined by ICP-AES. Furthermore, both UV/visible and EPR spectroscopy remained silence, indicating the enzyme a novel laccase with new metal compositions of active centre and spectral properties. The N-terminal amino acid sequence of the purified protein was APQISPQYPM. Together with MALDI-TOF analysis, the protein revealed a high homology of the protein with that from reported M. verrucaria. The highest activity was detected at pH 4.0 and at 30°C. The enzyme activity was significantly enhanced by Na(+), Mn(2+), Cu(2+) and Zn(2+) while inhibited by DTT, NaN(3) and halogen anions. The kinetic constant (Km) showed the enzyme was more affinitive to ABTS than other tested aromatic substrates. Twelve structurally different dyes could be effectively decolourised by the laccase within 10 min. The high production of the strain and novel properties of the laccase suggested its potential for biotechnological applications. 相似文献
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Accumulated evidence has shown that microRNAs (miRNAs) can functionally interact with a number of environmental factors (EFs) and their interactions critically affect phenotypes and diseases. Therefore, in-silico inference of disease-related miRNA-EF interactions is becoming crucial not only for the understanding of the mechanisms by which miRNAs and EFs contribute to disease, but also for disease diagnosis, treatment, and prognosis. In this paper, we analyzed the human miRNA-EF interaction data and revealed that miRNAs (EFs) with similar functions tend to interact with similar EFs (miRNAs) in the context of a given disease, which suggests a potential way to expand the current relation space of miRNAs, EFs, and diseases. Based on this observation, we further proposed a semi-supervised classifier based method (miREFScan) to predict novel disease-related interactions between miRNAs and EFs. As a result, the leave-one-out cross validation has shown that miREFScan obtained an AUC of 0.9564, indicating that miREFScan has a reliable performance. Moreover, we applied miREFScan to predict acute promyelocytic leukemia-related miRNA-EF interactions. The result shows that forty-nine of the top 1% predictions have been confirmed by experimental literature. In addition, using miREFScan we predicted and publicly released novel miRNA-EF interactions for 97 human diseases. Finally, we believe that miREFScan would be a useful bioinformatic resource for the research about the relationships among miRNAs, EFs, and human diseases. 相似文献
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Ou Wang Chunyan Wang Min Nie Quancai Cui Heng Guan Yan Jiang Mei Li Weibo Xia Xunwu Meng Xiaoping Xing 《PloS one》2012,7(9)