全文获取类型
收费全文 | 543篇 |
免费 | 30篇 |
出版年
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 12篇 |
2015年 | 13篇 |
2014年 | 19篇 |
2013年 | 23篇 |
2012年 | 23篇 |
2011年 | 17篇 |
2010年 | 10篇 |
2009年 | 15篇 |
2008年 | 30篇 |
2007年 | 23篇 |
2006年 | 28篇 |
2005年 | 33篇 |
2004年 | 24篇 |
2003年 | 28篇 |
2002年 | 26篇 |
2001年 | 15篇 |
2000年 | 26篇 |
1999年 | 22篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 12篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 19篇 |
1988年 | 12篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1969年 | 2篇 |
1968年 | 3篇 |
1966年 | 2篇 |
排序方式: 共有573条查询结果,搜索用时 31 毫秒
101.
102.
Thyroglobulin regulates follicular function and heterogeneity by suppressing thyroid-specific gene expression. 总被引:1,自引:0,他引:1
103.
Iwai K Okada T Nakazato K Fujimoto H Yamamoto Y Nakajima H 《Journal of strength and conditioning research / National Strength & Conditioning Association》2008,22(2):350-358
This study evaluated the sport-specific characteristics of the cross-sectional areas (CSAs) of trunk muscles and trunk muscle strength in wrestlers and judokas. We also examined whether their trunk muscles and muscle strength depended on athletic performance levels in each sport. The subjects comprised 14 male collegiate wrestlers and 14 judokas. Magnetic resonance imaging was used to assess the trunk muscle CSAs at the L3-4 level parallel to the lumbar disc space. A Biodex System3 was used to measure isokinetic trunk flexor and extensor muscle strength of peak torque, work, average torque, and average power. The absolute and relative CSAs of the trunk muscles in the wrestlers and judokas were significantly different (rectus abdominis: wrestling > judo, P < 0.05; obliques: wrestling < judo, P < 0.05; quadratus lumborum: wrestling < judo, P < 0.01). We confirmed that the absolute and relative trunk extensor and flexor strength of peak torque, work, and average torque were significantly higher in the collegiate wrestlers than in judokas. On athletic performance, the tendency of the CSAs and muscular strength of trunk muscles was not consistent with athletic performance levels in each sport. Our findings indicated that the sport-specific characteristics of the CSAs of the trunk muscles and trunk muscle strength obviously differed between the 2 similar sports. Athletes should practice the sport-specific training of trunk muscles and develop sport specificity in their sports. Particularly, wrestlers have to train in trunk flexion and extension motions, and judokas need to strengthen trunk rotation and lateral flexion motions. This information will be available for athletes as well as strength and technical training coaches in wrestling, judo, and the other sports. 相似文献
104.
Microarray technology has become employed widely for biological researchers to identify genes associated with conditions such as diseases and drugs. To date, many methods have been developed to analyze data covering a large number of genes, but they focus only on statistical significance and cannot decipher the data with biological concepts. Gene Ontology (GO) is utilized to understand the data with biological interpretation; however, it is restricted to specific ontology such as biological process, molecular function, and cellular component. Here, we attempted to apply MeSH (Medical Subject Headings) to interpret groups of genes from biological viewpoint. To assign MeSH terms to genes, in this study, contexts associated with genes are retrieved from full set of MEDLINE data using machine learning, and then extracted MeSH terms from retrieved articles. Utilizing the developed method, we implemented a software called BioCompass. It generates high-scoring lists and hierarchical lists for diseases MeSH terms associated with groups of genes to utilize MeSH and GO tree, and illustrated a wiring diagram by linking genes with extracted association from articles. Researchers can easily retrieve genes and keywords of interest, such as diseases and drugs, associated with groups of genes. Using retrieved MeSH terms and OMIM in conjunction with, we could obtain more disease information associated with target gene. BioCompass helps researchers to interpret groups of genes such as microarray data from a biological viewpoint. 相似文献
105.
Etsuko Sugino Katsuhiko Minoura Yasuko In Taizo Taniguchi Toshimasa Ishida 《Biochemical and biophysical research communications》2009,385(2):236-10886
The analysis of the self-assembly mechanism of the tau microtubule-binding domain (MBD) could provide the information needed to develop an effective method for the inhibition of the tau filament formation because of its core region that forms the filament. The MBD domain in the living body consists of similar three or four 31- to 32-residue repeats, namely 3RMBD (R134) and 4RMBD (R1234), respectively. The filament formation of the MBD has been mainly investigated by fluorescence spectroscopy utilizing the β-sheet structure-binding signal sensor thioflavin. This method observes the aggregation indirectly, and provides no information on the time-dependent change in aggregation size or volume. Thus, to determine the structure necessary for initiating MBD self-association, the dynamic light scattering (DLS) method was applied to the analysis of the aggregations of 3RMBD, 4RMBD and their component single repeats and shown to be a powerful tool for directly analyzing filament formation. DLS analysis clearly showed that the building unit for initiating the aggregation is the intermolecular R3-R3 disulfide-bonded dimer for 3RMBD and the intramolecular R2-R3 disulfide-bonded monomer for 4RMBD, and their aggregation processes under physiological condition differ from each other, which has not been clearly revealed by the conventional fluorescence method. The repeat-number-dependent aggregation model of MBD, together with the function of each repeat, reported in this paper should help to devise a method of preventing tau PHF formation. 相似文献
106.
Hiroto Nishizawa Takeshi Suzuki Takao Shioya Yuji Nakazato Hiroyuki Daida Nagomi Kurebayashi 《PloS one》2009,4(9)
Background
Abnormal Ca2+ transients are often observed in heart muscles under a variety of pathophysiological conditions including ventricular tachycardia. To clarify whether these abnormal Ca2+ transients can be attributed to abnormal action potential generation or abnormal Ca2+ handling/excitation-contraction (EC) coupling, we developed a procedure to determine Ca2+ and action potential signals at the cellular level in isolated heart tissues.Methodology/Principal Findings
After loading ventricular papillary muscle with rhod-2 and di-4-ANEPPS, mono-wavelength fluorescence images from rhod-2 and ratiometric images of two wavelengths of emission from di-4-ANEPPS were sequentially obtained. To mimic the ventricular tachycardia, the ventricular muscles were field-stimulated in non-flowing Krebs solution which elicited abnormal Ca2+ transients. For the failed and alternating Ca2+ transient generation, there were two types of causes, i.e., failed or abnormal action potential generation and abnormal EC coupling. In cells showing delayed initiation of Ca2+ transients with field stimulation, action potential onset was delayed and the rate of rise was slower than in healthy cells. Similar delayed onset was also observed in the presence of heptanol, an inhibitor of gap junction channels but having a non-specific channel blocking effect. A Na+ channel blocker, on the other hand, reduced the rate of rise of the action potentials but did not result in desynchronization of the action potentials. The delayed onset of action potentials can be explained primarily by impaired gap junctions and partly by Na+ channel inactivation.Conclusions/Significance
Our results indicate that there are multiple patterns for the causes of abnormal Ca2+ signals and that our methods are useful for investigating the physiology and pathophysiology of heart muscle. 相似文献107.
Regeneration processes of riparian Robinia
pseudoacacia forests after clear-cutting were investigated through dendroecological and microsatellite polymorphism analyses. Age determination
of regenerated R. pseudoacacia trees based on the dendroecological analysis revealed that forests regenerating after clear-cutting were composed of trees
that mostly established within a few years after clear-cutting. This suggests that the stimulus to form new shoots was evoked
by clear-cutting but faded within a few years. Genet identification via the microsatellite polymorphism analysis showed that
ramet trees belonging to the same genet were distributed in a cluster. Almost all trees regenerated asexually through new
ramet formation on the cut stumps and residual horizontal roots after clear-cutting. AMOVA with microsatellite markers showed
that among- and within-population variations contributed 6 and 94% to the total variation, respectively, suggesting that R.
pseudoacacia trees in the forests were initially established from seeds dispersed randomly from mother trees in a wide area. 相似文献
108.
Chikako Nagasato Naoko Kajimura Makoto Terauchi Yoshinobu Mineyuki Taizo Motomura 《Protoplasma》2014,251(6):1347-1357
In brown algae, membrane resources for the new cell partition during cytokinesis are mainly flat cisternae (FCs) and Golgi-derived vesicles. We used electron tomography coupled with rapid freezing/freeze substitution of zygotes to clarify the structure of transient membrane compartments during cytokinesis in Silvetia zygotes. After mitosis, an amorphous membranous structure, considered to be an FC intermediate was observed near endoplasmic reticulum clusters, lying between two daughter nuclei. FCs were arrayed at the cytokinetic plane, and a tubular membranous network was formed around them. This network might be formed by the consecutive fusion of spherical vesicles that are linked to the edges of FCs to form a membranous network (MN). At the initial stage of the formation of a membranous sac (MS) from the MN, the MS had flat and swollen parts, with the latter showing membranous tunnels. Coated pits were detected with high frequency at the swollen parts of the MS. This observation indicated that membranous tunnels disappeared by recycling of excess membrane via endocytosis, and the swollen part became flat. The MN appeared at the edges of the growing MS. MN and the MN-MS complex were observed along the cytokinetic plane in several spaces. The MS expanded by the incorporation of MN or other MS in its neighborhood. With the maturation of the new cell partition membrane, the thickness of the MS became constant and the membrane cavity disappeared. The changes in the surface area and volume of the transient membrane compartment during cytokinesis were analyzed from the tomographic data. 相似文献
109.
Although sialic acids have a key role in many aspects of human biology, the expression of polysialic acid (PSA) in human tissues is thought to be relatively rare. We identified a derivative of PSA called neuraminic acid-containing PSA or NeuPSA that was highly expressed in primary human melanoma tumors and in several cancer cell lines. Moreover, anti-NeuPSA antibodies could induce apoptosis of cancer cells. However, little was known about NeuPSA expression in normal or diseased tissues. In this study we investigated the complete expression profile of NeuPSA in human tissues and a few primary tumors using the anti-NeuPSA monoclonal antibody, SEAM 3. Almost every human tissue tested spanning a representative sample of all organ types was positive for SEAM 3 binding. Specificity of SEAM 3 binding was established by inhibition with NeuPSA but not closely related meningococcal C polysaccharide and loss of SEAM 3 binding when specimens were treated with periodate at high pH, which specifically destroys NeuPSA. Only subsets of cells in each specimen stained positive, and the relative staining between tissues was variable. The distribution and amount of NeuPSA antigen in tissues was correlated with known levels of polysialyltransferase PST or STX expression. The majority of anti-NeuPSA binding occurred intracellularly in the cytoplasm of cells. Tumors generally exhibited considerably increased staining compared with corresponding normal tissues. Identifying the diverse tissue distribution and intracellular location of NeuPSA provides a foundation for investigating the functional role of NeuPSA in human health and disease. 相似文献
110.
Kumagai T Okubo T Kataoka-Okubo H Chaki S Okuyama S Nakazato A 《Bioorganic & medicinal chemistry》2001,9(5):1357-1363
Structure-affinity relationships (SARs) of non-peptide CRF(1) antagonists suggest that such antagonists can be constructed of three units: a hydrophobic unit (Up-Area), a proton accepting unit (Central-Area), and an aromatic unit (Down-Area). Recently, various non-peptide corticotropin-releasing factor(1) (CRF(1)) receptor antagonists obtained by modification of the Central-Area have been reported. In contrast, we modified the Up-Area and presented 4- or 5-aryl-1,2,3,6-tetrahydropyridinopyrimidine derivatives including potent CRF receptor ligands 1a-c, and proposed that the 4- or 5-aryl-1,2,3,6-tetrahydropyridino moiety might be useful as a substituent in the Up-Area. Our interest shifted to the chemical modification in which the pyrimidine ring of 1a-c was replaced by other heterocycles, purine ring of 2, 3H-1,2,3-triazolo[4,5-d]pyrimidine ring of 3, purin-8-one ring of 4 and 7H-pyrrolo[2,3-d]pyrimidine ring of 5. Among them, 5-aryl-1,2,3,6-tetrahydropyridinopurine compound 6j (CRA0186) had the highest affinity for CRF(1) receptors (IC(50)=20nM). We report here the synthesis and SARs of derivatives 6-9. 相似文献