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991.
E Maestri L Camellini G Rossi G P Rossi C Dotti M Marchesi A Gnudi 《Hormones et métabolisme》1988,20(7):457-459
The circulating levels of aldosterone (A), cortisol (F), prolactin, ACTH and potassium and the PRA were studied in 8 (6 males and 2 females) healthy normotensive subjects after 5-hydroxy-tryptophan (5OHT), or pizotifen (Piz) or placebo oral administration. In the same subjects 5OHT was administered twice: after placebo and after dexamethasone pretreatment. The results showed a significant increase of A, ACTH and F after 5OHT plus placebo administration without any change of PRA, potassium or prolactin levels; dexamethasone pretreatment suppressed ACTH and F but was uneffective on the response of A to 5OHT. Only A levels showed a significant decrease after Piz administration, the other studied parameters were unaffected by the blockade of the 5HT2 receptors by Piz. The administration of placebo induced a slight but not significant decrease of the studied parameters. Our results suggest the existence of a physiologic serotonergic control of A secretion, a pituitary factor could be one of the putative links between the central serotonergic activation and the adrenal secretory response. 相似文献
992.
A D Mottino J M Pellegrino E E Guibert M G Roma E A Rodríguez Garay 《The International journal of biochemistry》1988,20(10):1113-1116
1. Bilirubin UDP-glucuronyltransferase activity and its dependence on substrate concentrations in rat liver, renal cortex and intestinal mucosa microsomes were studied. 2. Bilirubin monoglucuronide synthesis from unconjugated bilirubin was a higher capacity, lower affinity step in comparison with bilirubin diglucuronide formation in the three tissues tested. 3. Bilirubin glucuronide formation in liver microsomes showed a higher capacity but a lower affinity than extrahepatic ones. Renal cortex and intestinal mucosa exhibited similar kinetics parameters. 4. In vitro bilirubin glucuronidation in renal cortex and intestinal mucosa was quantitatively important as compared with the hepatic one. 相似文献
993.
In intact rat liver mitochondria acetaldehyde is oxidized by three functionally distinct dehydrogenase systems. Two of these reduce intramitochondrial nicotinamide adenine dinucleotide (NAD): one is operative with micromolar acetaldehyde concentrations and is stimulated by Mg2+, the other is operative with millimolar acetaldehyde concentrations and is stimulated by adenosine 5'-triphosphate (ATP). The third system reduces added NAD and is stimulated by rotenone. Connected to these systems, three aldehyde dehydrogenase isozymes (ALDH) have been purified: a low-Km ALDH activated by Mg2+, a high-Km ALDH activated by ATP and Mg2+, a high-Km ALDH activated by rotenone. The properties of some isozymes are affected by detergents. Thus, deoxycholate augments the stimulation of low-Km isozyme by Mg2+ and confers sensitivity to Mg2+ and ATP on one of the high-Km isozymes. A fourth isozyme has been purified. Its affinity for acetaldehyde is so low that it is very unlikely that acetaldehyde is the physiological substrate. 相似文献
994.
Methods for the cryopreservation of different stages of Trichinella parasites have been studied. For the cryopreservation of muscle stage larvae (MSL) of T. spiralis s.str. and T. nativa, four cryoprotectants were tested: dimethylsulfoxide, ethanediol, hydroxyethyl starch, and polyvinylpyrrolidone at different concentrations, times, and temperatures of incubation. The cooling rate was approximately 0.6 C min-1. After thawing and an incubation period of 3 hr, a high percentage (80%) of cryopreserved MSL were motile but were not infective for mice. For the cryopreservation of newborn larvae (NBL) of T. spiralis s.str., T. nativa, T. nelsoni, and T. pseudospiralis, 10% dimethylsulfoxide was used as cryoprotectant incubated at 37 C for 15 min. The cooling rate was also 0.6 C min-1. After storage in liquid nitrogen, thawing, and incubation of NBL in culture medium for 3 hr, 80% of NBL were motile. An average of 8% of T. spiralis, 6% T. nativa, and 0.5% T. pseudospiralis developed into MSL in mice. No cryopreserved NBL of T. nelsoni developed into MSL. Compared to unfrozen control groups NBL infectivity was 33% for T. spiralis, 21% for T. nativa, and 2% for T. pseudospiralis. 相似文献
995.
S Hrelia A Bordoni M Celadon E Turchetto P L Biagi C A Rossi 《Biochemical and biophysical research communications》1989,163(1):348-355
The first and rate limiting step in the conversion of linoleic and alpha-linolenic acid is catalyzed by the delta - 6 - desaturase (D6D) enzyme. Rat liver microsomal D6D activity decreases on linolenic acid at a rate proportional to the animal age; on alpha-linolenic acid the decrease in D6D activity begins only later than on linoleic acid. The fatty acid composition of liver microsomes determined by gas chromatographic analysis confirms the impairment of the enzymatic activity directly measured. Our data indicate a correlation between aging and D6D activity impairment. The loss of D6D activity may be a key factor in aging through altering the eicosanoid balance. 相似文献
996.
Human red blood cells as bioreactors for the release of 2',3'-dideoxycytidine, an inhibitor of HIV infectivity 总被引:1,自引:0,他引:1
M Magnani M Bianchi L Rossi V Stocchi 《Biochemical and biophysical research communications》1989,164(1):446-452
2',3'-Dideoxycytidine (ddCyd) is one of the most potent antiviral nucleosides for killing the human immunodeficiency virus (HIV). ddCyd is currently used in the treatment of severe HIV infections but due to its rapid clearance it must be administered to patients every 4 h reaching concentrations that are toxic. We have synthesized 2',3'-dideoxycytidine-5'-phosphate (ddCMP) as a prodrug, encapsulated it in human erythrocytes and found that it is dephosphorylated by endogenous pyrimidine nucleotidases and subsequently released by the cells as ddCyd. Encapsulated ddCMP does not affect erythrocyte metabolism and was not deaminated by cytidine deaminase. The dephosphorylation reaction has an apparent Km of 6mM, an optimum pH of 6.8 and is not inhibited by ATP or 2,3-bisphosphoglycerate. The efflux of ddCyd from the erythrocyte is a linear function of ddCyd concentration and relatively insensitive to nucleoside transporter inhibitors suggesting that ddCyd permeates the erythrocyte membrane predominantly by nonfacilitated diffusion. Thus, ddCMP-loaded erythrocytes might be used as endogenous bioreactors for ddCyd delivery in the treatment of HIV infection. 相似文献
997.
The rat olivocerebellar climbing fiber system has been investigated at the light and electron microscopic level with anterograde Phaseolus vulgaris leucoagglutinin (PHA-L) tracing. From PHA-L Injections in different parts of the inferior olive labelled axons could be traced to the contralateral cerebellum. Arriving in the deep cerebellar white matter, the olivocerebellar axons ran around and through the cerebellar nuclei. Plexuses of labelled terminal fibers appeared in the cerebellar nuclei, and the density of this innervation was estimated to 1-4 million varicosities per mm3. Ultrastructurally, these boutons engaged in asymmetric synapses with small dendrites. Bundles of labelled fibers continued into the folial white matter, and terminated as climbing fibers in sagittal zones of the cerebellar cortex. Both the cortical and nuclear terminations of the olivocerebellar system are strictly topographically organized. The plasticity of climbing fibers was studied after partial lesions of the inferior olive induced by 3-acetylpyridine. One to 6 months after the lesion, surviving climbing fibers demonstrated extensive sprouting. The newly formed axons originated from parent climbing fiber plexuses, grew in the direction of parallel fibers, and formed terminal plexuses around several neighbouring Purkinje cells. As normal climbing fiber terminals, these terminals formed asymmetric synapses with spines of proximal Purkinje cell dendrites, and evidence by Benedetti et al. (1983) shows that the regenerated innervation is electrophysiologically functional. It is suggested that denervated Purkinje cells release a trophic substance, which stimulate surviving climbing fibers to sprouting, axonal growth and synapse formation. 相似文献
998.
Purification and partial characterization of a lectin from the seeds of Trichosanthes kirilowii Maximowicz 总被引:2,自引:0,他引:2
A I Falasca A Abbondanza L Barbieri A Bolognesi C A Rossi F Stirpe 《FEBS letters》1989,246(1-2):159-162
A lectin was purified from the seeds of Trichosanthes kirilowii, belonging to the family Cucurbitaceae, growing in China. The lectin is a glycoprotein of 57 kDa, consists of two subunits with apparent molecular masses of 37 and 25 kDa, is specific for galactose, and is not mitogenic for human lymphocytes. 相似文献
999.
Daniela Rossi Mariangela Urbano Alice Pedrali Massimo Serra Daniele Zampieri Maria Grazia Mamolo Christian Laggner Caterina Zanette Chiara Florio Dirk Schepmann Bernard Wuensch Ornella Azzolina Simona Collina 《Bioorganic & medicinal chemistry》2010,18(3):1204-1212
In order to investigate the molecular features involved in sigma receptors (σ-Rs) binding, new compounds based on arylalkylaminoalcoholic, arylalkenyl- and arylalkylaminic scaffolds were synthesized and their affinity towards σ1- and σ2-Rs subtypes was evaluated. The most promising compounds were also screened for their affinity at μ-opioid, δ-opioid and κ-opioid receptors. Biological results are herein presented and discussed. 相似文献
1000.
The histocompatibility antigen profile of human fibroblasts transformed with SV40 virus has been investigated by determining their ability to specifically absorb HL-A alloantisera. Four out of four human adult skin fibroblast lines acquired, after SV40 transformation, the ability to absorb the HL-A alloantiserum VICTOR directed against the specificities HL-A5, W5. On the contrary, none of six embryonic fibroblast lines showed any qualitative or quantitative change of their HL-A antigenic profile. Similarly, murine, monkey and hamster cells could not absorb the activity of the HL-A alloantiserum VICTOR after SV40 transformation. It is suggested that the ‘new HL-A antigen’ specificity on human fibroblasts after SV40 transformation may be due to either a cross-reaction between HL-A specificities and antigenic structures present on glycoprotein(s) coded by the viral genome and expressed on the cell or to a change in the regulating mechanism of the expression of histocompatibility antigens on the cell surface, should the genetic information for all the HL-A specificities be present in the cell genome. 相似文献