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991.
Tomoko Tamura Masaharu Kuroda Tetsuo Oikawa Junko Kyozuka Kaede Terauchi Yoshiro Ishimaru Keiko Abe Tomiko Asakura 《Plant cell reports》2009,28(11):1615-1621
Signal peptide peptidase (SPP) is a multi-transmembrane aspartic proteinase involved in regulated intramembrane proteolysis,
which is implicated in fundamental life processes such as immunological response, cell signaling, tissue differentiation,
and embryogenesis. In this study, we identified two rice SPPs: OsSPP1 and OsSPP2. Green fluorescent protein-fused OsSPP1 and
OsSPP2 were localized to the ER in cultured plant cells. In situ hybridization showed that OsSPPs were strongly expressed
in vegetative shoot apex, young panicle, developing panicle, and the early developing florets. Undifferentiated cells, which
have the potential to differentiate into all of the aerial parts of the plant are presented in the shoot apex. OsSPPs are
located in both the undifferentiated cells, and the early differentiated cells at the shoot apex. These results suggest that
rice SPPs have an important function in differentiation and development at the shoot apex. The expression of the shoot apex
and ER localization is equal to dicot Arabidopsis thaliana, and will have common crucial roles in plant. 相似文献
992.
993.
Breast cancer is a widespread disease in Japan and across the world. Breast cancer cells, as well as most other types of cancer cells, have diverse chromosomal aberrations. Clarifying the character of these chromosomal aberrations should contribute to the development of more suitable therapies, along with the predictions of metastasis and prognosis. Twenty-four breast cancer cell lines were analyzed by bacterial artificial chromosome (BAC) array comparative genomic hybridization (CGH). The array slide contained duplicate spots of 4030 BAC clone DNAs covering the entire human genome with 1 Mbp resolution. In all 24 breast cancer cell lines, frequent and significant amplifications as well as deletions were detected by BAC array CGH. Common DNA copy number gains, detected in 60% (above 15 cell lines) of the 24 breast cancer cell lines were found in 76 BAC clones, located at 1q, 5p, 8q, 9p, 16p, 17q, and 20q. Moreover, common DNA copy number loss was detected in 136 BAC clones, located at 1q, 2q, 3p, 4p, 6q, 8p, 9p, 11p, 13q, 17p, 18q, 19p, Xp, and Xq. The DNA copy number abnormalities found included abnormality of the well-known oncogene cMYC (8q24.21); however, most of them were not reported to relate to breast cancer. BAC array CGH has great potential to detect DNA copy number abnormalities, and has revealed that breast cancer cell lines have substantial heterogeneity. 相似文献
994.
Saito Y Fukuhara A Nishio K Hayakawa M Ogawa Y Sakamoto H Fujii K Yoshida Y Niki E 《The Journal of nutritional biochemistry》2009,20(5):350-357
Coenzyme Q (CoQ) is a well-known electron transporter in the mitochondrial respiratory chain. Furthermore, ubiquinol (UQH(2))--a reduced form of ubiquinone (UQ)--has been shown to act as a radical-scavenging antioxidant. Some studies have reported the beneficial effect of CoQ addition to cultured cells; however, the cellular uptake and distribution of CoQ have not been elucidated. In the present study, we used rat pheochromocytoma PC12 cells to investigate and compare the cellular uptake and distribution of CoQ(10) and alpha-tocopherol (alphaT). UQ(10) or UQ(10)H(2) treatment resulted in an increase in the cellular content of both CoQ(10) in a time- and concentration-dependent manner. A subcellular fractionation study revealed that the added UQ(10) as well as UQ(10)H(2) mainly localized in the mitochondrial fraction, which is similar to the localization of endogenous CoQ but different from that of alphaT. The cellular distribution of alphaT directly corresponded to the lipid distribution, while the CoQ distribution did not show any relationship with the lipid distribution, particularly in the mitochondrial and microsomal fractions. These results indicate that the cellular distribution of CoQ is completely different from that of alphaT; moreover, a certain system which accumulates CoQ preferentially in mitochondria may be suggested. 相似文献
995.
Iwasaki Y Ohkawa K Sadakata H Kashiwadate A Takayama-Watanabe E Onitake K Watanabe A 《Development, growth & differentiation》2009,51(6):521-532
Seasonal change in spermatogenesis was examined in the restricted spermatogonium‐type testes of a teleost, Oryzias latipes. Histological observation revealed that the number of each stage of germ cells during most of the non‐reproductive season, from October to January (O–J period) was nearly half of that during the reproductive season, from May to July (M–J period), except for type B spermatogonia (B‐gonia), which was actually equal. As a result, the ratio of primary spermatocytes (P‐cytes) to B‐gonia was remarkably small in the O–J period. Despite the differences between both time periods, the proliferative activity of type A spermatogonia (A‐gonia), B‐gonia, or P‐cytes was at a similar level in both periods. Moreover, in cultured testes treated with bromodeoxyuridine as a cell‐lineage tracer, P‐cytes differentiated to spermatids in 11–15 days in both M–J and O–J periods. These indicate that spermatogenesis is active in each period at a different state. In the spermatogenic testis, A‐gonial proliferation was maintained by human follicle stimulating hormone/luteinizing hormone in culture. Whereas cell death of B‐gonia and/or P‐cytes gradually increased in the M–J period in spite of those cells being constant in population sizes. In transition to the O–J period, A‐gonia and P‐cytes first decreased, which was accompanied by a decrease in proliferative activity of A‐gonia and relative increase of dead cells from B‐gonia and/or P‐cytes against live P‐cytes. These suggest that A‐gonial proliferation and cell death of B‐gonia and/or P‐cytes that is induced coordinately with B‐gonial differentiation are critical for the spermatogenic control. 相似文献
996.
Taishi Sugawara Keisuke Ito Mitsunori Shiroishi Hidetsugu Asada Tatsuro Shimamura Norimichi Nomura Keiko Abe Takuya Kobayashi 《Biochemical and biophysical research communications》2009,382(4):704-710
Human TAS2 receptors (hTAS2Rs) perceive bitter tastants, but few studies have explored the structure-function relationships of these receptors. In this paper, we report our trials on the large-scale preparations of hTAS2Rs for structural analysis. Twenty-five hTAS2Rs were expressed using a GFP-fusion yeast system in which the constructs and the culture conditions (e.g., the signal sequence, incubation time and temperature after induction) were optimized by measuring GFP fluorescence. After optimization, five hTAS2Rs (hTAS2R7, hTAS2R8, hTAS2R16, hTAS2R41, and hTAS2R48) were expressed at levels greater than 1 mg protein/L of culture, which is a preferable level for purification and crystallization. Among these five bitter taste receptors, hTAS2R41 exhibited the highest detergent solubilization efficiency of 87.1% in n-dodecyl-β-d-maltopyranoside (DDM)/cholesteryl hemisuccinate (CHS). Fluorescence size-exclusion chromatography showed that hTAS2R41 exhibited monodispersity in DDM/CHS without aggregates, suggesting that hTAS2R41 is a good target for future crystallization trials. 相似文献
997.
Takuya Sugahara Keiko Ueno-Shuto Eriko Watanabe Kenichiro Kitamura Ai Mizuno Mary Ann Suico 《Experimental cell research》2009,315(19):3294-24
Epithelial sodium channel (ENaC) is a heteromultimeric Na+ channel at the apical membrane in the kidney, colon, and lung. Because ENaC plays a crucial role in regulating Na+ absorption and extracellular fluid volume, its dysregulation causes severe phenotypes including hypertension, hypokalemia, and airway obstruction. Despite the importance of ENaC, its protein quality control mechanism remains less established. Here we firstly show the role of calreticulin (CRT), a lectin-like molecular chaperone in the endoplasmic reticulum (ER), on the regulation of ENaC. Overexpression and knockdown analyses clearly indicated that CRT positively affects the expression of each ENaC subunit (α, β and γ). CRT overexpression also up-regulated the cell surface expression of α-, β- and γ-ENaC. Moreover, we found that CRT directly interacts with each ENaC subunit. Although CRT knockdown did not affect the de novo synthesis of ENaC subunits, CRT overexpression decreased α-, β- and γ-ENaC expression in the detergent (RIPA)-insoluble fraction, suggesting that CRT enhanced the solubility of ENaC subunits. Consistent with the increased intracellular and cell surface expression of ENaC subunits, increased channel activity of ENaC was also observed upon overexpression of CRT. Our study thus identifies CRT as an ER chaperone that regulates ENaC expression and function. 相似文献
998.
Ryosaku Tomioka Ai Kushida Ippei Izumi Keiko Fukushima Hiroko Ideo Katsuko Yamashita Shigehisa Hirose Yuji Saito 《Biochemical and biophysical research communications》2009,389(1):122-127
GOTO cells, a neuroblastoma cell line retaining the ability to differentiate into neuronal or Schwann cells, were found to be rich in membrane rafts containing ganglioside GM2 and hypersensitive to lipid raft-disrupting methyl-β-cyclodextrin (MβCD); the GM2-rich rafts and sensitivity to MβCD were markedly diminished upon their differentiation into Schwann cells. We first raised a monoclonal antibody that specifically binds to GOTO cells but not to differentiated Schwann cells and determined its target antigen as ganglioside GM2, which was shown to be highly concentrated in lipid rafts by its colocalization with flotillin, a marker protein of rafts. Disturbance of normal structure of the lipid raft by depleting its major constituent, cholesterol, with MβCD resulted in acute apoptotic cell death of GOTO cells, but little effects were seen on differentiated Schwann cells. Until this study, GM2-rich rafts are poorly characterized and MβCD hypersensitivity, which may have clinical implications, has not been reported. 相似文献
999.
Takafumi Matsumoto Yosuke Sato Takako Nakano Miyuki Eguchi-Tsuda Keiko Kan-o Takao Shimizu Shohei Sakuda Yoichi Nakanishi 《Biochemical and biophysical research communications》2009,390(1):103-79
Acidic mammalian chitinase is upregulated in response to allergen exposure in the lung. We investigated the effects of chitinase inhibitors, allosamidin (Allo) and demethylallosamidin (Dma), on asthmatic responses. Mice were subjected to IL-13 instillation into the airways or to ovalbumin sensitization plus exposure with or without treatment of Allo or Dma. Airway hyperresponsiveness (AHR) and inflammation were evaluated. Allo and Dma attenuated airway eosinophilia and the upregulation of eotaxin after IL-13 instillation, while Dma, but not Allo, suppressed AHR in IL-13-induced asthma. Allo or Dma suppressed the elevated chitinase activity in BAL fluids after IL-13 to similar levels. The bronchoprotective PGE2 levels in BAL fluids were elevated after IL-13 instillation. Allo, but not Dma, suppressed the overproduction of PGE2 and the expression of COX-2 and PGE synthase-1 induced by IL-13. In ovalbumin-induced asthma, Dma suppressed AHR more strongly than Allo. These findings suggest that Dma attenuates asthmatic responses induced by IL-13 without affecting PGE2 synthesis. Dma may have potential as therapeutic agents for asthma. 相似文献
1000.
Furuchi T Kosugi S Ohno K Egawa T Sekine M Katane M Homma H 《Analytical biochemistry》2009,384(2):207-212
Protein l-isoaspartyl/d-aspartyl o-methyltransferase (PIMT) is a widely expressed protein repair enzyme that restores isomerized aspartyl residues to their normal configuration. Current methods for measuring PIMT activity have limited sensitivity or require radioactivity. We have developed a highly sensitive new assay method to measure PIMT activity in cell lysates. As a substrate, we used a fluorescently labeled delta sleep-inducing peptide (DSIP) that contains an isoaspartyl residue: 7-nitro-2,1,3-benzoxadiazole (NBD)-DSIP(isoAsp). The PIMT-catalyzed transfer of a methyl group onto this substrate can be detected with a simple high-performance liquid chromatography (HPLC) procedure. After the enzyme reaction, the methylated form of the peptide is stable and can be reproducibly separated from the unmethylated form in an acidic solvent and fluorometrically detected by HPLC. The limit of detection was estimated to be approximately 1 pmol of NBD-DSIP(isoAsp) (signal/noise ratio [S/N] = 3), and the quantitation limit of the activity was approximately 18 μg of total cell lysate from HEK293 cells (10.7 pmol/min/mg protein). This assay method is sensitive enough to detect PIMT activity in biological samples without the use of radioisotopes, offering significant advantages over previously reported methods. 相似文献