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991.
Enzymic Synthesis of Leukotriene B4 in Guinea Pig Brain 总被引:1,自引:8,他引:1
Takao Shimizu Yutaka Takusagawa Takashi Izumi Nobuya Ohishi Yousuke Seyama 《Journal of neurochemistry》1987,48(5):1541-1546
Leukotriene B4 [5(S), 12(R)-dihydroxy-6, 14-cis-8,10-trans-eicosatetraenoic acid] was obtained from endogenous arachidonic acid when slices of the guinea pig brain cortex were incubated with the calcium ionophore A 23187. Enzymes involved in its synthesis, arachidonate 5-lipoxygenase [arachidonic acid to 5(S)-hydroperoxy-6-trans-8,11,14-cis-eicosatetraenoic acid and subsequently to leukotriene A4] and leukotriene A4 hydrolase (leukotriene A4 to B4), were present in the cytosol fraction. Arachidonate 5-lipoxygenase was Ca2+-dependent, and was stimulated by ATP and the microsomal membrane, as was noted for the enzyme from mast cells. The lipid hydroperoxides stimulated 5-lipoxygenase by four- to sixfold. The leukotriene A4 hydrolase activity was rich in brain, and the specific activity (0.4 nmol/min/mg of protein) was much the same as that of guinea pig leukocytes. High activities of these enzymes were detected in the olfactory bulb, pituitary gland, hypothalamus, and cerebral cortex. Since leukotriene B4 is enzymically synthesized in the brain, possible roles related to neuronal functions or dysfunctions deserve to be examined. 相似文献
992.
混交林和纯竹林与毛竹害螨爆发成灾关系研究 总被引:9,自引:0,他引:9
报道在福建省6个不同生态区域内检查10对纯竹林与混交林受南京裂爪螨(Schizotetranychus nanjingensis)、竹缺爪螨(Aponychus corpuzae)、竹刺瘿螨(Aculus bambusae)对毛竹危害情况.结果表明,纯竹林受螨害重,危害指数达22.1%~44.7%,平均35%.混交林受害轻,危害指数为2.7%~28.6%,平均17.5%,混交林与纯竹林之间受害程度经t-测验表明均达到极显著差异.6个样地中纯竹林害螨总量高于其相对的混交林。分别达67.74%、152.47%、299.5%、857.75%、331.67%、26.55%。平均为289.28%;调查混交林天敌竹盲走螨(Typhlodromus bambusae)总量分别比相对纯竹林高95.45%、-18.13%、207.69%、837.5%、190.3%,平均262.5%.纯竹林中益、害螨比例分别达1:27、1:21、1:233、1:282、1:27,平均1:118,而其相对的混交林益、害螨比例为1:12、1:12、1:30、1:3、1:3、1:20,平均1:13.由此可见,纯竹林受螨害程度、害螨总量平均是混交林的2倍,而天敌数量少于相对混交林的2~3倍,益、害螨比例显著低于混交林(t=2.975,P=0.003).本项研究揭示了由于受人为干扰(集约化管理、劈草、垦复)破坏了毛竹林原有的益螨-害螨-寄主植物之间相对稳定的平衡。导致毛竹害螨种群突发性增长,证明了纯竹林是诱发毛竹害螨爆发成灾成因的重要因素之一。 相似文献
993.
Bumhwan Lee Akihiko Tajima Joonwan Kim Yutaka Yamagata Teruyuki Nagamune 《Biotechnology and Bioprocess Engineering》2010,15(1):145-151
In this study, antibody-based protein microarrays for high-throughput immunoassay were fabricated on an aldehydemodified indium-tin
oxide glass plate using the electrospray deposition (ESD) method and their characteristics were evaluated immunochemically.
The microarrays were also integrated into microfluidic chips with a polydimethylsiloxane (PDMS) micro-channel to detect human
cytokines, which were quantitatively analyzed with a high resolution chargecoupled device. Simultaneous detection of various
antigens was performed using the microarrays with considerable sensitivity (ca. 100 pg/mL). The results of this study indicate
that microfluidic chip comprising a protein microarray formed by the ESD method and a PDMS micro-channel could be easy to
handle, and offers high-throughput detection of molecular biomarkers. 相似文献
994.
Monoclonal antibody R24 distinguishes between different N-acetyl- and N-glycolylneuraminic acid derivatives of ganglioside GD3 总被引:3,自引:0,他引:3
Monoclonal antibody (MAb) R24 was previously shown to be directed toward ganglioside GD3 [Pukel, C. S., Lloyd, K. O., Travassos, L. R., Dippold, W. G., Oettgen, H. F., and Old, L. J. (1982) J. Exp. Med. 155, 1133-1147]. The structural specificity of the MAb has now been further characterized based on binding to structurally related glycolipids, including four GD3 derivatives with different N-acetylneuraminic acid (NeuAc) and N-glycolylneuraminic acid (NeuGc) substituents. Three assay systems (enzyme immunostaining on thin-layer chromatography, enzyme-linked immunosorbent assay, and immune adherence inhibition assay) were used. MAb R24 was found to react with (NeuAc-NeuAc-)GD3 and (NeuAc-NeuGc-)GD3 but not with (NeuGc-NeuAc-)GD3 or (NeuGc-NeuGc-)GD3. These results clearly indicate that the outer sialic acid (Sia) moiety of GD3 is crucial and must be a NeuAc residue, while the inner sialic acid is less involved in binding to the MAb and can be either NeuAc or NeuGc. The MAb was also found to cross-react weakly with two gangliosides, GT1a and GQ1b, but none of other gangliosides nor neutral glycolipids tested reacted. These findings suggest that the epitope detected by MAb R24 is the trisaccharide structure NeuAc alpha 2----8Sia alpha 2----3Gal-, which must be in a terminal position. 相似文献
995.
Seno T Hamaguchi M Ashihara E Kohno M Ishino H Yamamoto A Kadoya M Nakamura K Murakami K Matoba S Maekawa T Kawahito Y 《PloS one》2011,6(10):e25541
Aim
15-Deoxy-Δ12,14 Prostaglandin J2 (15d-PGJ2) is a ligand of peroxisome proliferator-activated receptor γ (PPARγ) having diverse effects such as the differentiation of adipocytes and atherosclerotic lesion formation. 15d-PGJ2 can also regulate the expression of inflammatory mediators on immune cells independent of PPARγ. We investigated the antiatherogenic effect of 15d-PGJ2.Methods
We fed apolipoprotein (apo) E-deficient female mice a Western-type diet from 8 to 16 wk of age and administered 1 mg/kg/day 15d-PGJ2 intraperitoneally. We measured atherosclerotic lesions at the aortic root, and examined the expression of macrophage and inflammatory atherosclerotic molecules by immunohistochemical and real-time PCR in the lesion.Results
Atherosclerotic lesion formation was reduced in apo E-null mice treated with 15d-PGJ2, as compared to in the controls. Immunohistochemical and real-time PCR analyses showed that the expression of MCP-1, TNF-α, and MMP-9 in atherosclerotic lesions was significantly decreased in 15d-PGJ2 treated mice. The 15d-PGJ2 also reduced the expression of macrophages and RelA mRNA in atherosclerotic lesions.Conclusion
This is the first report 15d-PGJ2, a natural PPARγ agonist, can improve atherosclerotic lesions in vivo. 15d-PGJ2 may be a beneficial therapeutic agent for atherosclerosis. 相似文献996.
Aixinjueluo W Furukawa K Zhang Q Hamamura K Tokuda N Yoshida S Ueda R Furukawa K 《The Journal of biological chemistry》2005,280(33):29828-29836
Anti-GD2 ganglioside antibodies could be a promising, novel therapeutic approach to the eradication of human small cell lung cancers, as anti-GD2 monoclonal antibodies (mAbs) induced apoptosis of small cell lung cancer cells in culture. In this study, we analyzed the mechanisms for the apoptosis of these cells by anti-GD2 mAbs and elucidated the mechanisms by which apoptosis signals were transduced via reduction in the phosphorylation levels of focal adhesion kinase (FAK) and the activation of a MAPK family member, p38, upon the antibody binding. Knock down of FAK resulted in apoptosis and p38 activation. The inhibition of p38 activity blocked antibody-induced apoptosis, indicating that p38 is involved in this process. Immunoprecipitation-immunoblotting analysis of immune precipitates with anti-FAK or anti-integrin antibodies using an anti-GD2 mAb revealed that GD2 could be precipitated with integrin and/or FAK. These results suggested that GD2, integrin, and FAK form a huge molecular complex across the plasma membrane. Taken together with the fact that GD2+ cells showed marked detachment from the plate during apoptosis, GD2+ small cell lung cancer cells seemed to undergo anoikis through the conformational changes of integrin molecules and subsequent FAK dephosphorylation. 相似文献
997.
Haruhiko Tokuda Jun Kotoyori Atsushi Suzuki Yutaka Oiso Osamu Kozawa 《Journal of cellular biochemistry》1993,52(2):220-226
We investigated the effects of vitamin D3 on the signaling pathways by prostaglandin E2 (PGE2) in osteoblast-like MC3T3-E1 cells. The pretreatment with 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3), an active form of vitamin D3, significantly inhibited cAMP accumulation induced by 10 μM PGE2 in a dose-dependent manner in the range between 1 pM and 1 nM. This effect of 1,25-(OH)2D3 was dependent on the time of pretreatment up to 8 h. 1,25-(OH)2D3 also inhibited the cAMP accumulation induced by NaF, a GTP-binding protein activator, or forskolin which directly activates adenylate cyclase. On the other hand, 1,25-(OH)2D3 significantly inhibited PGE2-induced IP3 formation in a dose-dependent manner between 10 pM and 1 nM. However, 1,25-(OH)2D3 had little effect on NaF-induced IP3 formation. The pretreatment with 24,25-dihydroxyvitamin D3, an inactive form of vitamin D3, affected neither cAMP accumulation nor IP3 formation induced by PGE2. These results strongly suggest that 1,25-(OH)2D3 modulates the signaling by PGE2 in osteoblast-like cells as follows: the inhibitory effect on the cAMP production is exerted at a point downstream from adenylate cyclase and the inhibitory effect on the phosphoinositide hydrolysis is exerted at the point between the PGE2 receptor and GTP-binding protein, probably Gi2. 相似文献
998.
Uptake ofl-[35S]cysteic acid (L-CA) in rat synaptic membrane vesicles was investigated. Preincubation with either 10 mMl-glutamic acid (L-Glu), 25 mM L-CA, 10 mMdl-homocysteic acid, or 25 mMdl-2-amino-4-phosphonobutyrate on membrane vesicles enhanced L-[35S]CA and L-[3H]Glu uptake. Na+ (5 mM) and omission of Cl– from the assay medium decreased L-[35S]CA uptake into both 10 mM L-Glu-loaded and non-loaded membrane vesicles. The anion transport blockers, 4-acetamide-4-isothiocyano-2,2-disulfonic acid stibene (SITS) and 4,4-diisothiocyano-2,2-disulfonic acid stilbene (DIDS), inhibited L-[35S]CA uptake in a dose-dependent manner. The maximal uptake rate for L-[35S]CA was decreased by 50 M SITS, while the apparent Km value of L-CA was not changed. SITS increased the EC50 value of Cl– for L-[35S]CA uptake from 5 mM to 10 mM with reduction of the maximal effect. These results suggested that L-[35S]CA uptake into synaptic membrane vesicles was mediated by a SITS-sensitive hetero-exchange transport with non-labeled substrates.Abbreviations SITS
4-Acetamide-4-isothiocyano-2,2-disulfonic acid stilbene
- DIDS
4,4-Diisothiocyano-2,2-disulfonic acid stilbene
- CA
Cysteic acid
- APB
2-Amino-4-phosphonobutyrate
- CSA
Cysteine sulfinic acid
- EGTA
Ethyleneglycol bis(aminoethylether) tetraacetate
- GABA
-Aminobutyric acid 相似文献
999.
Yuko Watanabe Eri Furukawa Hideki Tatsukawa Hisashi Hashimoto Yasuhiro Kamei Yoshihito Taniguchi 《Bioscience, biotechnology, and biochemistry》2018,82(7):1165-1168
Transglutaminase (TG) is an essential enzyme to catalyze cross-linking reactions of epidermal proteins. Recently, we biochemically characterized human skin TG orthologues for medaka (Oryzias latipes), a model fish. By genome editing, gene-modified fishes for the two orthologues were obtained, both of which lack the ordinal enzymes. These fish appeared to exhibit higher susceptibility to osmolality at the period of larvae. 相似文献
1000.
The ultrastructure of the purified and lyophilized endotoxin from Escherichia coli O111 was observed by ultrathin sectioning. Onion-like globular membrane structures were observed in addition to rod-like and ribbon-like structures, indicating the existence of a globular membrane structure even in the dried state. 相似文献