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91.
Kawada-Matsuo M Mazda Y Oogai Y Kajiya M Kawai T Yamada S Miyawaki S Oho T Komatsuzawa H 《PloS one》2012,7(3):e33382
Streptococcus mutans is a cariogenic pathogen that produces an extracellular polysaccharide (glucan) from dietary sugars, which allows it to establish a reproductive niche and secrete acids that degrade tooth enamel. While two enzymes (GlmS and NagB) are known to be key factors affecting the entrance of amino sugars into glycolysis and cell wall synthesis in several other bacteria, their roles in S. mutans remain unclear. Therefore, we investigated the roles of GlmS and NagB in S. mutans sugar metabolism and determined whether they have an effect on virulence. NagB expression increased in the presence of GlcNAc while GlmS expression decreased, suggesting that the regulation of these enzymes, which functionally oppose one another, is dependent on the concentration of environmental GlcNAc. A glmS-inactivated mutant could not grow in the absence of GlcNAc, while nagB-inactivated mutant growth was decreased in the presence of GlcNAc. Also, nagB inactivation was found to decrease the expression of virulence factors, including cell-surface protein antigen and glucosyltransferase, and to decrease biofilm formation and saliva-induced S. mutans aggregation, while glmS inactivation had the opposite effects on virulence factor expression and bacterial aggregation. Our results suggest that GlmS and NagB function in sugar metabolism in opposing directions, increasing and decreasing S. mutans virulence, respectively. 相似文献
92.
Sugane T Tobe T Hamaguchi W Shimada I Maeno K Miyata J Suzuki T Kimizuka T Morita T Sakamoto S Tsukamoto S 《Bioorganic & medicinal chemistry》2012,20(1):34-41
To identify novel glycine transporter 1(GlyT1) inhibitors with greater selectivity relative to GlyT2 and improved aqueous solubility, we synthesized a series of 4H-1,2,4-triazole derivatives with heteroaromatic rings at the 4-position and investigated their structure-activity relationships. Replacement of the 2-fluorophenyl group of lead compound 5 with various aromatic groups led to the identification of 5-(3-biphenyl-4-yl-5-ethyl-4H-1,2,4-triazol-4-yl)isoquinoline (15) with 38-fold selectivity between GlyT1 and GlyT2. 15 also showed improved aqueous solubility and in vivo efficacy on (+)-HA966-induced hyperlocomotion in mice over the lead compound. 相似文献
93.
Synthetic oligodeoxynucleotides containing unmethylated CpG motifs (CpG-ODNs) function as powerful immune adjuvants by activating macrophages, dendritic cells, and B cells. However, the molecular recognition mechanism that initiates signaling in response to CpG-ODN has not fully been identified. We show in this study that peritoneal macrophages from SCID mice having mutations in the catalytic subunit of DNA-protein kinase (DNA-PKcs) were almost completely defective in the production of IL-10 and in ERK activation when treated with CpG-ODN. In contrast, IL-12 p70 production significantly increased. Furthermore, small interfering RNA (siRNA)-mediated knockdown of DNA-PKcs expression in the mouse monocyte/macrophage cell line RAW264.7 led to reduced IL-10 production and ERK activation by CpG-ODN. IL-10 and IL-12 p70 production, but not ERK activation, are blocked by chloroquine, an inhibitor of endosomal acidification. Endosomal translocation of CpG-ODN in a complex with cationic liposomes consisting of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) (CpG-DOTAP-liposomes) decreased IL-10 production and ERK activation, whereas the endosomal escape of CpG-ODN in a complex with cationic liposomes consisting of DOTAP and dioleyl-phosphatidylethanolamine (DOPE) (CpG-DOTAP/DOPE-liposomes) increased. In contrast, IL-12 p70 production was increased by CpG-DOTAP-liposomes and decreased by CpG-DOTAP/DOPE-liposomes. IL-10 production induced by CpG-DOTAP/DOPE-liposomes was not observed in macrophages from SCID mice. Thus, our findings suggest that DNA-PKcs in the cytoplasm play an important role in CpG-ODN-induced production of IL-10 in macrophages. In addition, DNA-PKcs-mediated production of IL-10 and IL-12 p70 can be regulated by manipulating the intracellular trafficking of CpG-ODN in macrophages. 相似文献
94.
Malaria parasites require TLR9 signaling for immune evasion by activating regulatory T cells 总被引:4,自引:0,他引:4
Hisaeda H Tetsutani K Imai T Moriya C Tu L Hamano S Duan X Chou B Ishida H Aramaki A Shen J Ishii KJ Coban C Akira S Takeda K Yasutomo K Torii M Himeno K 《Journal of immunology (Baltimore, Md. : 1950)》2008,180(4):2496-2503
Malaria is still a life-threatening infectious disease that continues to produce 2 million deaths annually. Malaria parasites have acquired immune escape mechanisms and prevent the development of sterile immunity. Regulatory T cells (Tregs) have been reported to contribute to immune evasion during malaria in mice and humans, suggesting that activating Tregs is one of the mechanisms by which malaria parasites subvert host immune systems. However, little is known about how these parasites activate Tregs. We herein show that TLR9 signaling to dendritic cells (DCs) is crucial for activation of Tregs. Infection of mice with the rodent malaria parasite Plasmodium yoelii activates Tregs, leading to enhancement of their suppressive function. In vitro activation of Tregs requires the interaction of DCs with parasites in a TLR9-dependent manner. Furthermore, TLR9(-/-) mice are partially resistant to lethal infection, and this is associated with impaired activation of Tregs and subsequent development of effector T cells. Thus, malaria parasites require TLR9 to activate Tregs for immune escape. 相似文献
95.
Thirumurugan T Ito Y Kubo T Serizawa A Kurata N 《Molecular genetics and genomics : MGG》2008,279(3):279-289
A HAP complex, which consists of three subunits, namely HAP2 (also called NF-YA or CBF-B), HAP3 (NF-YB/CBF-A) and HAP5 (NF-YC/CBF-C),
binds to CCAAT sequences in a promoter to control the expression of target genes. We identified 10 HAP2 genes, 11 HAP3 genes and 7 HAP5 genes in the rice genome. All the three HAP family genes encode a protein with a conserved domain in each family and various non-conserved regions in both length and
amino acid sequence. These genes showed various expression patterns depending on genes, and various combinations of overlapped
expression of the HAP2, HAP3 and HAP5 genes were observed. Furthermore, protein interaction analyses showed interaction of OsHAP3A, a ubiquitously expressed HAP3
subunit of rice, with specific members of HAP5. These results indicate that the formation of specific complex with various
HAP subunits combinations can be achieved by both tissue specific expression of three subunit genes and specific interaction
of three subunit proteins. This may suggest that the HAP complexes may control various aspects of rice growth and development
through tissue specific expression and complex formation of three subunit members.
Nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession numbers AB288027 to
AB288048 and BR000373 to BR000375. 相似文献
96.
本文提出和描述了产自我国西北新疆南部喀拉塔克剖面的一个牙形类新亚种 Polygnathus communis gan-caohuensis,并根据以前出版的信息 ,命名了另一个新亚种 Polygnathus communis carmanae。种系发生研究揭示了Polygnathus communis Branson et Mehl的亚种对于法门阶最上部至韦宪阶地层的划分是至关重要的。此种的 cari-na→ gancaohuensis谱系 ,连同发现于喀拉塔克剖面的菊石、有孔虫和腕足动物 ,被认为是划分杜内 -韦宪阶界线的潜在的标志化石。因此 ,喀拉塔克剖面有可能成为全球杜内 -韦宪阶界线的一个候选层型剖面。 相似文献
97.
Keiji Takabe Miyuki Takeuchi Takahiko Sato Masaki Ito Minoru Fujita 《Journal of plant research》2001,114(4):509-515
O -methyltransferase, and cinnnamyl alcohol dehydrogenase were localized to differentiating xylem. These enzymes are particularly
abundant during secondary wall formation. Immunolabeling was observed on polysomes and in the cytosol of the cells during
secondary wall formation, indicating that these enzymes are synthesized in the polysomes and released in the cytosol. The
synthesis of monolignols might occur in the cytosol. Immunolabeling of anionic peroxidase was also localized to the differentiating
xylem, particularly during secondary wall formation. The labeling, however, was observed in the rough endoplasmic reticulum
(r-ER), the Golgi apparatus, and the plasma membrane, indicating that peroxidase is synthesized in the r-ER, transported to
the Golgi apparatus, and localized on the plasma membrane by fusion of the Golgi vesicles to the membrane.
Received 3 September 2001/ Accepted in revised form 16 October 2001 相似文献
98.
H Ishihara Y Hayashi T Hara Y Aramaki S Tsuchiya K Koike 《Biochemical and biophysical research communications》1991,174(2):839-845
Asialofetuin-tacked liposomes (AF-liposomes) encapsulating interferon (IFN)-gamma were bound and internalized into a human hepatoma cell line, HepG2 cells, selectively through asialoglycoprotein receptor, but not non-tacked liposomes (N-liposomes). AF-liposomal IFN-gamma was more effective for inhibition of viral DNA replication in hepatitis B virus (HBV)-producing clone from HepG2 cells transfected with HBV-DNA than N-liposomal IFN-gamma. AF-liposomes may increase the therapeutic potential of IFN-gamma through asialoglycoprotein receptor in treating HBV-infected hepatocytes. 相似文献
99.
Haruki Yamada Yukihiro Aramaki Toshio Miyazaki 《Biochimica et Biophysica Acta (BBA)/General Subjects》1977,497(2):396-407
A non-dialyzable specific agglutination factor of myxamoebae obtained from culture broth during the growth phase of Dictyostelium discoideum NC-4 was thermostable but the agglutination activity disappeared below pH 5.0. In the case of formalinized myxamoebae, digestion of the factor with Pronase decreased the activity, but periodate treatment of the factor did not affect the activity. Myxamoebal agglutination by this factor was inhibited by the addition of uronic acid, polyuronide (protuberic acid), and cell-surface polysaccharide prepared from the myxamoebae, but the agglutination was not affected by citric acid or glycine.The factor was purified by ethanol precipitation, column chromatography using DEAE-cellulose and Sepharose-2B, and zone electrophoresis. Chemical analysis of the purified factor gave 61.0% carbohydrate and 26.1% protein, and glucose, mannose, xylose and rhamnose (molar ratios of 9.3 : 3.2 : 2.1 : 1.0) were detected as the component sugars. The content of uronic acid was 12.9%.When the myxamoebae of the growth phase were starved in Millipore-supporting medium, the agglutination activity was detected in the supernatant of the medium. 相似文献
100.