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491.
492.
Dicoumarol biosynthesis: origin of the methylene bridge 总被引:1,自引:0,他引:1
493.
Coupled NaCl entry into Necturus gallbladder epithelial cells 总被引:12,自引:0,他引:12
494.
495.
Peter Koch Jensen Richard S. Fisher Kenneth R. Spring 《The Journal of membrane biology》1984,82(1):95-104
Summary WhenNecturus gallbladder epithelium is treated with ouabain the cells swell rapidly for 20–30 minutes then stabilize at a cell volume 30% greater than control. The cells then begin to shrink slowly to below control size. During the initial rapid swelling phase cell Na activity, measured with microelectrodes, rises rapidly. Calculations of the quantity of intracellular Na suggest that the volume increase is due to NaCl entry. Once the peak cell volume is achieved, the quantity of Na in the cell does not increase, suggesting that NaCl entry has been inhibited. We tested for inhibition of apical NaCl entry during ouabain treatment either by suddenly reducing the NaCl concentration in the mucosal bath or by adding bumetanide to the perfusate. Both maneuvers caused rapid cell shrinkage during the initial phase of the ouabain experiment, but had no effect on cell volume if performed during the slow shrinkage period. The lack of sensitivity to the composition of the mucosal bath during the shrinkage period occurred because of apparent feedback inhibition of NaCl entry. Another maneuver, reduction of the Na in the serosal bath to 10mm, also resulted in inhibition of apical NaCl uptake. The slow shrinkage which occurred after one or more hours of ouabain treatment was sensitive to the transmembrane gradients for K and Cl across the basolateral membrane and could be inhibited by bumetanide. Thus during pump inhibition inNecturus gallbladder epithelium cell Na and volume first increase due to continuing NaCl entry and then cell volume slowly decreases due to inhibition of the apical NaCl entry and activation of basolateral KCl exit. 相似文献
496.
DMSO was compared to morphine in rats to determine its relative analgesic effects. DMSO produces analgesia that is comparable in magnitude to morphine although its duration (6–7 hrs) is longer than that of morphine (≤ 2 hrs). DMSO apparently produced analgesia both by an action at the site at which it was administered as well as at a site that was remote to the site of administration. The mechanism of action of DMSO is apparently different from that of morphine because naloxone, a specific narcotic antagonist, does not block the analgesic effect of DMSO. However, DMSO has toxic effects such as hematuria (bloody urine). Therefore, the toxicity observed may restrict the clinical usefulness of DMSO as an analgesic drug. 相似文献
497.
Shanmugam Mayilraj Anna H. Kaksonen Ralf Cord-Ruwisch Peter Schumann Cathrin Spröer Brian J. Tindall Stefan Spring 《Extremophiles : life under extreme conditions》2009,13(2):247-255
A novel moderately thermophilic and halophilic sulfate-reducing bacterium, strain TeStT, was isolated from production water of an oil field in Northern Germany near Hamburg. The cells were Gram-negative, straight
to slightly curved rods and motile by a single polar flagellum. Only hydrogen and formate served as electron donors, whereas
a wide variety of organic substrates and CO2 could be used as carbon sources. Sulfate, sulfite, thiosulfate and sulfur were used as electron acceptors, but not nitrate
or ferric iron. The novel isolate was negative for oxidase, catalase and desulfoviridin enzyme activity. Cytochromes were
present and predominantly of the c-type. Whole-cells fatty acid patterns were dominated by the branched-chain fatty acids anteiso-C15:0, iso-C15:0, iso-C17:0 and anteiso-C17:0. As major respiratory lipoquinones partially saturated derivates of menaquinone 6 [MK-6(H2) and probably MK-6(H4)] were identified. The G + C content of the genomic DNA was 41.3 mol% (HPLC method). An analysis of the 16S rRNA gene sequence
indicated that strain TeStT belongs to the family Desulfohalobiaceae within the class Deltaproteobacteria. The most closely related species with a sequence
similarity of 95.0% was Desulfonauticus submarinus suggesting an affiliation of TeStT to the genus Desulfonauticus. The novel isolate could be clearly distinguished from Desulfonauticus submarinus by its ability to grow chemolithoautotrophically and hence should be assigned to a novel species for which the name Desulfonauticus autotrophicus sp. nov. is proposed. The type strain is TeStT (=DSM 4206T = JCM 13028T).
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
498.
Background
Vertigo and dizziness are symptoms which are reported frequently in clinical practice. We aimed to develop diagnostic indices for four prevalent vertiginous diseases: benign paroxysmal positional vertigo (BPPV), Menière's disease (MD), vestibular migraine (VM), and phobic postural vertigo (PPV). 相似文献499.
Micro-organisms have been isolated that can utilize o-coumaric acid as a sole carbon source with the subsequent production of 4-hydroxycoumarin and dicoumarol. One of these organisms, Penicillium jenseni, has been used to examine the biosynthesis of dicoumarol. Certain thermophilic fungi have also been found that can convert o-coumaric acid into dicoumarol. 相似文献
500.
Panupun Limpachayaporn Michael Schäfers Otmar Schober Klaus Kopka Günter Haufe 《Bioorganic & medicinal chemistry》2013,21(7):2025-2036
Downstream caspases-3 and -7 are essential to execute the programmed type I cell death (apoptosis). In order to better understand their role, specific inhibitors of these enzymes are required, which after radiolabeling can be applied to non-invasively visualize and monitor apoptotic pathways in vivo using Positron Emission Tomography (PET). Therefore, 2-methoxyethyl-, 2-methoxypropyl-, 2-ethoxymethyl-, 2-(2-fluoroethoxymethyl)-, and 2-(2,2,2-trifluoroethoxymethyl)pyrrolidinyl analogues of (S)-5-[1-(2-methoxymethylpyrrolidinyl)sulfonyl]isatin (2) were prepared and their in vitro binding affinities towards caspases-1, -3, -6 and -7 were evaluated and compared to that of the lead structure 2. While the inhibition potencies against caspases-1 and -6 were in the micromolar range, all synthesized compounds exhibited excellent and selective inhibition of caspases-3 and -7 in the nanomolar range up to IC50 = 4.79 nM and 7.47 nM, respectively. These highly potent 2-substituted analogues of 2 might be developed as anti-apoptosis agents and some selected fluorinated inhibitors might be useful as potential PET radiotracers for apoptosis imaging after 18F-labeling. 相似文献