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961.
Akira Hayashi Kyosuke Kinoshita Yasuo Miyake Chung-Hyo Cho 《Bioscience, biotechnology, and biochemistry》2013,77(8):1699-1704
The phase change for an amylose solution in the binary solvent system of dimethylsulfoxide (DMSO) with water was investigated under various conditions from sol to gel. The phase change was determined with measurements of the fluorescent depolarization and other methods by varying the solvent constitution at 25°C, and then varying the temperature at 10% of DMSO concentration.The phase diagrams obtained with both variables were substantially similar and were also similar to those for an aqueous agarose solution. This similarity in phase diagram suggests a similar gel formation mechanism of amylose to agarose.It was found that the phase separation point for the amylose solution agreed with the gel formation point and also with the starting point of retrogradation. 相似文献
962.
963.
Yasuo Yamamoto Eiji Kawanishi Yuichi Koga Shigeki Sakamaki Toshiaki Sakamoto Kiichiro Ueta Yasuaki Matsushita Chiaki Kuriyama Minoru Tsuda-Tsukimoto Sumihiro Nomura 《Bioorganic & medicinal chemistry letters》2013,23(20):5641-5645
Inhibition of renal sodium-dependent glucose cotransporter 2 (SGLT2) increases urinary glucose excretion (UGE), and thus reduces blood glucose levels in hyperglycemia. A series of N-glucosides was synthesized for biological evaluation as human SGLT2 (hSGLT2) inhibitors. Among these compounds, N-glucoside 9d possessing an indole core structure showed good in vitro activity (IC50 = 7.1 nM against hSGLT2). Furthermore, 9d exhibited favorable in vivo potency with regard to UGE in rats based on good pharmacokinetic profiles. 相似文献
964.
965.
966.
Ikeda T Sun L Tsuruoka N Ishigaki Y Yoshitomi Y Yoshitake Y Yonekura H 《The Biochemical journal》2011,436(2):399-407
sFlt-1 (soluble Flt-1) potently inhibits angiogenesis by binding extracellularly to VEGF (vascular endothelial growth factor). In the present paper, we report that hypoxia down-regulates sFlt-1 expression in HMVECs (human microvascular endothelial cells), a constituent of microvessels where angiogenesis occurs. Hypoxia (5-1% O?) increased VEGF expression in HMVECs. In contrast, the levels of sFlt-1 mRNA and protein in HMVECs decreased significantly as the O? concentration fell, whereas mFlt-1 (membrane-bound Flt-1) mRNA and protein remained unchanged. This suggested that hypoxia selectively regulates alternative 3'-end processing of sFlt-1 pre-mRNA. We have also demonstrated that sFlt-1 overexpression in lentiviral-construct-infected HMVECs counteracted VEGF-induced endothelial cell growth. We next identified cis-elements involved in sFlt-1 mRNA processing in HMVECs using a human Flt-1 minigene and found that two non-contiguous AUUAAA sequences function as the poly(A) signal. Furthermore, we identified a cis-element in intron 13 that regulates sFlt-1 mRNA processing. Mutagenesis of the U-rich region in intron 13 caused a significant decrease in the soluble-form/membrane-form RNA ratio in the minigene-transfected HMVECs. These results suggest that decreased sFlt-1 expression due to hypoxia contributes to hypoxia-induced angiogenesis and reveals a novel mechanism regulating angiogenesis by alternative mRNA 3'-end processing. 相似文献
967.
A tyrosine-phosphorylated protein of 33 kDa is shown to be present in the solubilized yolk fraction of Xenopus laevis oocytes, eggs, and early embryos. The phosphoprotein is lipovitellin 2 as demonstrated by immunoprecipitation and mass spectrometry studies, and is termed pp33/LV2. Sub-cellular fractionation and immunoblotting studies demonstrate that pp33/LV2 is stably present in the Triton X-100-resistant and SDS-soluble yolk fractions during oogenesis, oocyte maturation, and early embryogenesis. From after the swimming tadpole stages (stage 39~), however, it becomes partly soluble to Triton X-100-containing buffer and all disappear thereafter (stage 48~49). In vitro enzyme assays with the use of the tyrosine phosphatase LAR and the tyrosine kinase Src demonstrate the reversible nature of the tyrosine phosphorylation of pp33/LV2. Microinjection studies demonstrate that the solubilized yolk fractions, but not those immunodepleted of pp33/LV2 or those pretreated with LAR, inhibit progesterone- or insulin-induced oocyte maturation. A pp33/LV2-like protein seems to present in two Xenopus subspecies, one other frog species, and two fish species, but not in other amphibian species, such as newt and salamander. These results suggest that LV2, in its tyrosine-phosphorylated form, serves in a cellular function in a species-specific manner, but the mechanism is still unknown. 相似文献
968.
Yuichi Kano Kaori Ohnishi Yasuo Tomida Naoyo Ikeda Naomi Iwawaki Masahiko Miyagawa Yasushi Harada Hidetaka Ichiyanagi Katsutoshi Watanabe 《Environmental Biology of Fishes》2011,92(4):447-460
In the autumn of 2004, a typhoon caused a catastrophic flood of the Miyagawa River in Japan. Based upon snorkeling surveys
conducted every autumn from 2005 to 2009, we monitored the post flood fluctuation of the local fish assemblages at nine sites
of both the main stream and subsidiary streams of the river. Results revealed that species richness significantly increased
from 2005 to 2009. In addition, the fish densities of eight species significantly increased over the same period, whereas
the density of one species decreased, and that of eight others remained unchanged. Categorization based on Euclidean distance
revealed five main clusters from the nine sites. Among these sites, fish assemblages within subsidiary streams were stable
as they remained within the same clusters while those in the main stream were dynamically variable through time as they changed
cluster membership. In addition, the Euclidean distance between two arbitrary fish assemblages was positively correlated with
environmental distance (the Euclidean distance calculated based on river width, depth, velocity and pebble size), time distance,
and spatial distance along the river. In conclusion, the fish assemblages were dynamically and regularly altered and varied
in the five years after the flood, except for those in the subsidiary streams, and such variation was related to environmental,
temporal and spatial variation. 相似文献
969.
Wichit S Jittmittraphap A Hidari KI Thaisomboonsuk B Petmitr S Ubol S Aoki C Itonori S Morita K Suzuki T Suzuki Y Jampangern W 《Microbiology and immunology》2011,55(2):135-140
Dengue viruses infect cells by attaching to a surface receptor which remains unknown. The putative receptor molecules of dengue virus type 2 on the surface of mosquito (AP-61) and mammalian (LLC-MK2) cell lines were investigated. The immunochemical detection and structural analysis of carbohydrates demonstrated that the neutral glycosphingolipids, L-3 (GlcNAcβ1-3Manβ1-4Glcβ1-1'Cer) in AP-61 cells, and nLc(4) Cer (Galβ1-4GlcNAcβ1-3Galβ1-4Glcβ1-1'Cer) in LLC-MK2 cells were recognized by the virus. These findings strongly suggest that neutral glycosphingolipids share the key determinant for virus binding and that the β-GlcNAc residue may play an important role in dengue virus binding to the host cell surface. 相似文献
970.
Ascidians are members of the vertebrate sister group Urochordata. Their larvae exhibit a chordate body plan, which forms by a highly accelerated embryonic strategy involving a fixed cell lineage and small cell numbers. We report a detailed analysis of the specification of three of the five pairs of motoneurons in the ascidian Ciona intestinalis and show that despite well-conserved gene expression patterns and embryological outcomes compared with vertebrates, key signalling molecules have adopted different roles. We employed a combination of cell ablation and gene manipulation to analyse the function of two signalling molecules with key roles in vertebrate motoneuron specification that are known to be expressed equivalently in ascidians: the inducer Sonic hedgehog, produced ventrally by the notochord and floorplate; and the inhibitory BMP2/4, produced on the lateral/dorsal side of the neural plate. Our surprising conclusion is that neither BMP2/4 signalling nor the ventral cell lineages expressing hedgehog play crucial roles in motoneuron formation in Ciona. Furthermore, BMP2/4 overexpression induced ectopic motoneurons, the opposite of its vertebrate role. We suggest that the specification of motoneurons has been modified during ascidian evolution, such that BMP2/4 has adopted a redundant inductive role rather than a repressive role and Nodal, expressed upstream of BMP2/4 in the dorsal neural tube precursors, acts as a motoneuron inducer during normal development. Thus, our results uncover significant differences in the mechanisms used for motoneuron specification within chordates and also highlight the dangers of interpreting equivalent expression patterns as indicative of conserved function in evo-devo studies. 相似文献