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1.
Tau is a microtubule-associated protein implicated in neurodegenerative tauopathies. Six tau isoforms are generated from a single gene through alternative splicing of exons 2, 3 and 10 in human brain. Differential expression of tau isoforms has been detected in different brain areas, during neurodevelopment and in neurodegenerative disorders. However, the biological significance of different tau isoforms is not clear. Here, we investigated the individual effect of six different isoforms of tau on cell proliferation and the possible mechanisms by transient expression of eGFP-labeled tau isoform plasmid in N2a cells. Our study showed the transfection efficiency was comparable between different isoforms of tau by examining GFP expression. Compared with other isoforms, we found expression of 1N3R-tau significantly inhibited cell proliferation by Cell Counting Kit-8 assay and BrdU incorporation. Flow cytometry analysis further showed expression of 1N3R-tau induced S phase arrest. Compared with the longest isoform of tau, expression of 1N3R-tau induced cyclin E translocation from the nuclei to cytoplasm, while it did not change the level of cell cycle checkpoint proteins. These data indicate that 1N3R-tau inhibits cell proliferation through inducing S phase arrest.  相似文献   
2.
Glioblastoma (GBM), a malignant and lethal tumor, remains a big threat to human health and life. Increasing explorations have confirmed that long noncoding RNAs are involved in the tumorigenesis and development of multiple cancers. Nevertheless, the regulatory mechanism of (long intergenic nonprotein coding RNA 1579 LINC01579) in GBM remains to be investigated. In this study, the expression of LINC01579 was upregulated in GBM cells and LINC01579 knockdown inhibited cell proliferation as well as promoted cell apoptosis. Additionally, LINC01579 acted as a sponge for miR-139-5p in GBM and eukaryotic translation initiation factor 4 gamma 2 (EIF4G2) was found to be a downstream target of miR-139-5p. Furthermore, the positive correlation of LINC01579 and EIF4G2 as well as the converse correlation between miR-139-5p and LINC01579 (or EIF4G2) were revealed by the experiments. Based on rescue assays, EIF4G2 overexpression or miR-139-5p inhibitor partially recovered the function of LINC01579 knockdown on cell proliferation and apoptosis. In summary, the results of this study verified that LINC01579 modulated cell proliferation and cell apoptosis in GBM by competitively binding with miR-139-5p to regulate EIF4G2, which provided a new clue to figure out potential therapy for patients suffered from GBM.  相似文献   
3.
Mannans are hemicellulosic polysaccharides that are considered to have both structural and storage functions in the plant cell wall. However, it is not yet known how mannans function in Arabidopsis (Arabidopsis thaliana) seed mucilage. In this study, CELLULOSE SYNTHASE-LIKE A2 (CSLA2; At5g22740) expression was observed in several seed tissues, including the epidermal cells of developing seed coats. Disruption of CSLA2 resulted in thinner adherent mucilage halos, although the total amount of the adherent mucilage did not change compared with the wild type. This suggested that the adherent mucilage in the mutant was more compact compared with that of the wild type. In accordance with the role of CSLA2 in glucomannan synthesis, csla2-1 mucilage contained 30% less mannosyl and glucosyl content than did the wild type. No appreciable changes in the composition, structure, or macromolecular properties were observed for nonmannan polysaccharides in mutant mucilage. Biochemical analysis revealed that cellulose crystallinity was substantially reduced in csla2-1 mucilage; this was supported by the removal of most mucilage cellulose through treatment of csla2-1 seeds with endo-β-glucanase. Mutation in CSLA2 also resulted in altered spatial distribution of cellulose and an absence of birefringent cellulose microfibrils within the adherent mucilage. As with the observed changes in crystalline cellulose, the spatial distribution of pectin was also modified in csla2-1 mucilage. Taken together, our results demonstrate that glucomannans synthesized by CSLA2 are involved in modulating the structure of adherent mucilage, potentially through altering cellulose organization and crystallization.Mannan polysaccharides are a complex set of hemicellulosic cell wall polymers that are considered to have both structural and storage functions. Based on the particular chemical composition of the backbone and the side chains, mannan polysaccharides are classified into four types: pure mannan, glucomannan, galactomannan, and galactoglucomannan (Moreira and Filho, 2008; Wang et al., 2012; Pauly et al., 2013). Each of these polysaccharides is composed of a β-1,4-linked backbone containing Man or a combination of Glc and Man residues. In addition, the mannan backbone can be substituted with side chains of α-1,6-linked Gal residues. Mannan polysaccharides have been proposed to cross link with cellulose and other hemicelluloses via hydrogen bonds (Fry, 1986; Iiyama et al., 1994; Obel et al., 2007; Scheller and Ulvskov, 2010). Furthermore, it has been reported that heteromannans with different levels of substitution can interact with cellulose in diverse ways (Whitney et al., 1998). Together, these observations indicate the complexity of mannan polysaccharides in the context of cell wall architecture.CELLULOSE SYNTHASE-LIKE A (CSLA) enzymes have been shown to have mannan synthase activity in vitro. These enzymes polymerize the β-1,4-linked backbone of mannans or glucomannans, depending on the substrates (GDP-Man and/or GDP-Glc) provided (Richmond and Somerville, 2000; Liepman et al., 2005, 2007; Pauly et al., 2013). In Arabidopsis (Arabidopsis thaliana), nine CSLA genes have been identified; different CSLAs are responsible for the synthesis of different mannan types (Liepman et al., 2005, 2007). CSLA7 has mannan synthase activity in vitro (Liepman et al., 2005) and has been shown to synthesize stem glucomannan in vivo (Goubet et al., 2009). Disrupting the CSLA7 gene results in defective pollen growth and embryo lethality phenotypes in Arabidopsis, indicating structural or signaling functions of mannan polysaccharides during plant embryo development (Goubet et al., 2003). A mutation in CSLA9 results in the inhibition of Agrobacterium tumefaciens-mediated root transformation in the rat4 mutant (Zhu et al., 2003). CSLA2, CSLA3, and CSLA9 are proposed to play nonredundant roles in the biosynthesis of stem glucomannans, although mutations in CSLA2, CSLA3, or CSLA9 have no effect on stem development or strength (Goubet et al., 2009). All of the Arabidopsis CSLA proteins have been shown to be involved in the biosynthesis of mannan polysaccharides in the plant cell wall (Liepman et al., 2005, 2007), although the precise physiological functions of only CSLA7 and CSLA9 have been conclusively demonstrated.In Arabidopsis, when mature dry seeds are hydrated, gel-like mucilage is extruded to envelop the entire seed. Ruthenium red staining of Arabidopsis seeds reveals two different mucilage layers, termed the nonadherent and the adherent mucilage layers (Western et al., 2000; Macquet et al., 2007a). The outer, nonadherent mucilage is loosely attached and can be easily extracted by shaking seeds in water. Compositional and linkage analyses suggest that this layer is almost exclusively composed of unbranched rhamnogalacturonan I (RG-I) (>80% to 90%), with small amounts of branched RG-I, arabinoxylan, and high methylesterified homogalacturonan (HG). By contrast, the inner, adherent mucilage layer is tightly attached to the seed and can only be removed by strong acid or base treatment, or by enzymatic digestion (Macquet et al., 2007a; Huang et al., 2011; Walker et al., 2011). As with the nonadherent layer, adherent mucilage is also mainly composed of unbranched RG-I, but with small numbers of arabinan and galactan ramifications (Penfield et al., 2001; Willats et al., 2001; Dean et al., 2007; Macquet et al., 2007a, 2007b; Arsovski et al., 2009; Haughn and Western, 2012). There are also minor amounts of pectic HG in the adherent mucilage, with high methylesterified HG in the external domain compared with the internal domain of the adherent layer (Willats et al., 2001; Macquet et al., 2007a; Rautengarten et al., 2008; Sullivan et al., 2011; Saez-Aguayo et al., 2013). In addition, the adherent mucilage contains cellulose (Blake et al., 2006; Macquet et al., 2007a), which is entangled with RG-I and is thought to anchor the pectin-rich mucilage onto seeds (Macquet et al., 2007a; Harpaz-Saad et al., 2011, 2012; Mendu et al., 2011; Sullivan et al., 2011). As such, Arabidopsis seed mucilage is considered to be a useful model for investigating the biosynthesis of cell wall polysaccharides and how this process is regulated in vivo (Haughn and Western, 2012).Screening for altered seed coat mucilage has led to the identification of several genes encoding enzymes that are involved in the biosynthesis or modification of mucilage components. RHAMNOSE SYNTHASE2/MUCILAGE-MODIFIED4 (MUM4) is responsible for the synthesis of UDP-l-Rha (Usadel et al., 2004; Western et al., 2004; Oka et al., 2007). The putative GALACTURONSYLTRANSFERASE11 can potentially synthesize mucilage RG-I or HG pectin from UDP-d-GalUA (Caffall et al., 2009). GALACTURONSYLTRANSFERASE-LIKE5 appears to function in the regulation of the final size of the mucilage RG-I (Kong et al., 2011, 2013). Mutant seeds defective in these genes display reduced thickness of the extruded mucilage layer compared with wild-type Arabidopsis seeds.RG-I deposited in the apoplast of seed coat epidermal cells appears to be synthesized in a branched form that is subsequently modified by enzymes in the apoplast. MUM2 encodes a β-galactosidase that removes Gal residues from RG-I side chains (Dean et al., 2007; Macquet et al., 2007b). β-XYLOSIDASE1 encodes an α-l-arabinfuranosidase that removes Ara residues from RG-I side chains (Arsovski et al., 2009). Disruptions of these genes lead to defective hydration properties and affect the extrusion of mucilage. Furthermore, correct methylesterification of mucilage HG is also required for mucilage extrusion. HG is secreted into the wall in a high methylesterified form that can then be enzymatically demethylesterified by pectin methylesterases (PMEs; Bosch and Hepler, 2005). PECTIN METHYLESTERASE INHIBITOR6 (PMEI6) inhibits PME activities (Saez-Aguayo et al., 2013). The subtilisin-like Ser protease (SBT1.7) can activate other PME inhibitors, but not PMEI6 (Rautengarten et al., 2008; Saez-Aguayo et al., 2013). Disruption of either PMEI6 or SBT1.7 results in the delay of mucilage release.Although cellulose is present at low levels in adherent mucilage, it plays an important adhesive role for the attachment of mucilage pectin to the seed coat epidermal cells. The orientation and amount of pectin associated with the cellulose network is largely determined by cellulose conformation properties (Macquet et al., 2007a; Haughn and Western, 2012). Previous studies have demonstrated that CELLULOSE SYNTHASE A5 (CESA5) is required for the production of seed mucilage cellulose and the adherent mucilage in the cesa5 mutant can be easily extracted with water (Harpaz-Saad et al., 2011, 2012; Mendu et al., 2011; Sullivan et al., 2011).Despite all of these discoveries, large gaps remain in the current knowledge of the biosynthesis and functions of mucilage polysaccharides in seed coats. In this study, we show that CSLA2 is involved in the biosynthesis of mucilage glucomannan. Furthermore, we show that CSLA2 functions in the maintenance of the normal structure of the adherent mucilage layer through modifying the mucilage cellulose ultrastructure.  相似文献   
4.
A survey was performed to investigate the infection status of freshwater fish with zoonotic trematode metacercariae in Phnom Penh and Pursat Province, Cambodia. All collected fish with ice were transferred to our laboratory and examined using the artificial digestion method. In fish from Phnom Penh, 2 kinds of metacercariae (Opisthorchis viverrini and Haplorchis yokogawai) were detected. O. viverrini metacercariae were positive in 37 (50.0%) of 74 fish in 11 species (average no. metacercariae/fish, 18.6). H. yokogawai metacercariae were detected in 23 (57.5%) of 40 fish in 5 species (average no. metacercariae/fish, 21.0). In fish from Pursat Province, 5 kinds of metacercariae (O. viverrini, H. yokogawai, Haplorchis pumilio, Centrocestus formosanus, and Procerovum sp.) were detected; O. viverrini metacercariae (n=3) in 2 fish species (Henicorhynchus lineatus and Puntioplites falcifer), H. yokogawai metacercariae (n=51) in 1 species (P. falcifer), H. pumilio metacercariae (n=476) in 2 species (H. lineatus and Pristolepis fasciata), C. formosanus metacercariae (n=1) in 1 species (H. lineatus), and Procerovum sp. metacercariae (n=63) in 1 species (Anabas testudineus). From the above results, it has been confirmed that various freshwater fish play the role of a second intermediate host for zoonotic trematodes (O. viverrini, H. yokogawai, H. pumilio, C. formosanus, and Procerovum sp.) in Cambodia.  相似文献   
5.
Paleoparasitology is the application of conventional or molecular investigative techniques to archeological samples in order to reveal parasitic infection patterns among past populations. Although pioneering studies already have reported key paleoparasitological findings around the world, the same sorts of studies had not, until very recently, been conducted in sufficient numbers in Korea. Mummified remains of individuals dating to the Korean Joseon Dynasty actually have proved very meaningful to concerned researchers, owing particularly to their superb preservation status, which makes them ideal subjects for paleoparasitological studies. Over the past several years, our study series on Korean mummies has yielded very pertinent data on parasitic infection patterns prevailing among certain Joseon Dynasty populations. In this short review, we summarized the findings and achievements of our recent paleoparasitological examinations of Joseon mummies and discussed about the prospects for future research in this vein.  相似文献   
6.
The mutation spectrum of deafness genes may vary in different ethnical groups. In this study, we investigated the genetic etiology of nonsyndromic deafness in four consanguineous and two multiplex Uyghur families in which mutations in common deafness genes GJB2, SLC26A4 and MT-RNR1 were excluded. Targeted next-generation sequencing of 97 deafness genes was performed in the probands of each family. Novel pathogenic mutations were identified in four probands including the p.L416R/p.A438T compound heterozygous mutations in TMC1, the homozygous p.V1880E mutation in MYO7A, c.1238delT frameshifting deletion in PCDH15 and c.9690+1G>A splice site mutation in MYO15A. Co-segregation of the mutations and the deafness were confirmed within each family by Sanger sequencing. No pathogenic mutations were identified in one multiplex family and one consanguineous family. Our study provided a useful piece of information for the genetic etiology of deafness in Uyghurs.  相似文献   
7.
In order to investigate the status of intestinal helminthic infections in Cambodia, epidemiological surveys were carried out on a national scale, including 19 provinces. A total of 32,201 fecal samples were collected from schoolchildren and adults between 2006 and 2011 and examined once by the Kato-Katz thick smear technique. The overall egg positive rate of intestinal helminths was 26.2%. The prevalence of hookworms was the highest (9.6%), followed by that of Opisthorchis viverrini/minute intestinal flukes (Ov/MIF) (5.7%), Ascaris lumbricoides (4.6%), and Trichuris trichiura (4.1%). Other types of parasites detected were Enterobius vermicularis (1.1%), Taenia spp. (0.4%), and Hymenolepis spp. (0.2%). The northwestern regions such as the Siem Reap, Oddar Meanchey, and Banteay Meanchey Provinces showed higher prevalences (17.4-22.3%) of hookworms than the other localities. The southwestern areas, including Koh Kong and Preah Sihanouk Provinces showed higher prevalences of A. lumbricoides (17.5-19.2%) and T. trichiura (6.1-21.0%). Meanwhile, the central and southern areas, in particular, Takeo and Kampong Cham Provinces, showed high prevalences of Ov/MIF (23.8-24.0%). The results indicate that a considerably high prevalence of intestinal helminths has been revealed in Cambodia, and thus sustained national parasite control projects are necessary to reduce morbidity due to parasitic infections in Cambodia.  相似文献   
8.
9.
UV-B irradiation reduced the levels of omega-3 fatty acid, eicosapentaenoic acid (EPA, 20:53) and docosahexaenoic acid (DHA, 22:63), in microalgae; the degree of reduction varied with species.Chaetoceros calcitrans andSkeletonema costatum were high UV-B tolerant species, followed byPhaeodactylum tricornutum, Chroomonas salina, Pavlova lutheri, andThalassiosira pseudonana.Isochrysis galbana (T.ISO) andProrocentrum micans were UV- B sensitive. Cells in logarithmic phase were most sensitive to UV- B irradiation. Nitrate-, phosphate-, or sulphate-starved cells were more UV-B sensitive than non-starved cells grown in a complete basal medium. A relatively short exposure to high UV-B was more damaging than a longer exposure to lower irradiance. Visible light intensity levels had a profound impact on the sensitivity of microalgal cultures to UV-B, with high levels decreasing UV-B dependent damage. Addition of polyamines (putrescine, spermidine or spermine) or an amino acid (cysteine) to the culture medium minimized the reduction of omega-3 fatty acid content in microalgae caused by UV-B irradiation.Author for correspondence  相似文献   
10.
【目的】研究副溶血性弧菌(Vibrioparahaemolyticus,VP)和霍乱弧菌(Vibriocholera,VC)混合生物被膜的形成过程。【方法】在4、8、12、24、36、48、60、72 h测定单独条件下VP、VC及其混合后生物被膜的形成情况,通过结晶紫染色法、平板菌落计数法、测定胞外多糖、胞外蛋白,通过荧光原位杂交(FISH)观察混合生物被膜形成。【结果】虽然形成的混合生物被膜量介于VC和VP之间,但混合生物被膜在形成过程中,成熟期后生物被膜量的变化较小,对环境的抗性增强。混合生物被膜中拥有更多的活菌,混合生物被膜形成过程中胞外蛋白和胞外多糖的变化体现出其可能在对抵御不适应环境中起重要作用,通过FISH可观察到不同时期生物被膜的变化过程。【结论】VC与VP共同形成生物被膜的过程中,混合生物被膜总量虽然减少,但混合生物被膜中拥有更多的活菌,这可能引起更大的危害。研究混合生物被膜形成过程中被膜的变化,可为有害生物被膜的控制提供基础。  相似文献   
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