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We have reported that spermidine N1-acetyltransferase has a larger role than ornithine decarboxylase in putrescine synthesis in chick duodenum induced by 1 alpha,25-dihydroxycholecalciferol (calcitriol) [Shinki, T., Kadofuku, T., Sato, T. and Suda, T. (1986) J. Biol. Chem. 261, 11712-11716]. In the present study, spermidine N1-acetyltransferase was purified from the duodenal cytosol of calcitriol-treated chicks to homogeneity judged by SDS/polyacrylamide gel electrophoresis. The purified enzyme converted spermidine only to N1-acetyl-spermidine. The apparent molecular mass of the purified spermidine N1-acetyltransferase was found to be 36 kDa by gel filtration on Sephacryl S-200 and 18 kDa by SDS/polyacrylamide gel electrophoresis. When duodenal crude 105,000 x g extracts were directly applied to a Sephacryl S-200 column without prior purification, three peaks with spermidine N1-acetyltransferase activity appeared. The first peak was in the void volume, the second peak was in the fraction corresponding to an apparent molecular mass of 70 kDa, and the third peak was in the fraction corresponding to 36 kDa. These results suggest that spermidine N1-acetyltransferase exists as a dimer of the 18 kDa subunits and is stabilized in (a) form(s) bound to other components or proteins in intact cells. 相似文献
4.
H Suda H Nagai T Miura T Iwama A Koda 《Prostaglandins, leukotrienes, and essential fatty acids》1992,47(1):41-49
The effects of 4-bromo-5-(3-ethoxy-4-methoxybenzylamino)-3(2H)-pyridazinone (NZ-107) on immediate type hypersensitivity reactions in rats and guinea-pigs were studied. 1. When NZ-107, at a dose of 50 mg/kg (i.p.) or 100 mg/kg (orally), was administered to rats, 48-h homologous passive cutaneous anaphylaxis (PCA) reaction and histamine-, leukotriene C4 (LTC4)- and leukotriene D4 (LTD4)-induced skin reactions were suppressed by the agent. 2. NZ-107 (10(-6) g/ml) inhibited both LTC4- and LTD4-induced contractions of isolated rat stomach smooth muscle. 3. NZ-107 inhibited antigen-induced histamine release from rat peritoneal mast cells by 26% at a concentration of 10(-4) g/ml. 4. NZ-107, at doses of 25 and 50 mg/kg (orally), significantly inhibited guinea-pig 3-h heterologous PCA reaction. 5. NZ-107 inhibited antigen-induced histamine release from guinea-pig lung tissue by 17% and 48% at concentrations of 5 x 10(-5) and 10(-4) g/ml, respectively. 6. NZ-107, at doses of 25 and 50 mg/kg (i.p.), inhibited antigen-induced bronchoconstriction and eosinophil accumulation in the bronchoalveolar lavage fluid (BALF) of guinea-pigs. These results suggest that NZ-107 has anti-allergic action including inhibition of eosinophil accumulation in an antigen-challenged airway lesion in rats and guinea-pigs. The anti-allergic action of this agent is thought to be due to its action as a histamine and LT antagonist and its consequent inhibition of antigen-induced histamine release. 相似文献
5.
The presence of immunoreactive endothelin (IR-ET) in human saliva and rat parotid gland was investigated by radioimmunoassay. The IR-ET concentration (mean +/- SEM) in saliva taken from normal volunteers was 2.0 +/- 0.2 pmol/l (n = 15). The IR-ET concentration in rat parotid gland was 19.2 +/- 2.2 fmol/g wet weight (n = 10). Fast protein liquid chromatography (FPLC) of human saliva extract revealed 6 peaks; one peak eluting in the void volume, one in a position between ET-1 and -3, and the other four in the positions of synthetic ET-1, -2, -3 and big ET(1-38), respectively. A similar pattern of rat parotid gland extract was noted with FPLC, except that there was no peak after the void volume. Presence of endothelin, a potent growth factor, in saliva and salivary gland points to a role in maintaining the integrity of the oral and gastrointestinal tract mucosa. 相似文献
6.
K Inada S Endo K Takahashi M Suzuki T Narita T Yoshida H Suda T Komuro M Yoshida 《Microbiology and immunology》1991,35(4):303-314
We established a new method of plasma treatment for the removal of interfering factors in the plasma to allow detection of endotoxin by limulus test. The limulus test used was an endotoxin-specific chromogenic test, the Endospecy test. Perchloric acid (PCA) treatment and centrifugation (PCA method) is usually used to remove interfering factors from plasma, with the precipitate being discarded and the supernatant used to detect endotoxin. As the solubilized precipitates of endotoxin-spiked plasma and some patient plasma were found to contain the Endospecy activity, we have devised a new method assaying endotoxin in both the supernatant and precipitate. This study confirmed that the solubilized precipitate of endotoxin-spiked plasma had Endospecy activity and found that the precipitate had other endotoxin activities, such as lethality in galactosamine-sensitized mice and pyrogenicity in rabbits. We also confirmed that interfering factors were completely removed from plasma samples by this new method. The endotoxin level after the new PCA method was found to be about 8 times higher than that determined after PCA treatment and the new PCA method surpasses the conventional PCA method with regard to the positive rate of endotoxin contents in clinical samples. These results indicate that the new PCA method is superior to the PCA method as a plasma pretreatment method for limulus test. 相似文献
7.
Tanaka Kiyoshi; Suda Yoshiko; Kondo Noriaki; Sugahara Kiyoshi 《Plant & cell physiology》1985,26(7):1425-1431
The relationship between O3 tolerance and the chloroplast H2O2scavenging system (PS I 相似文献
8.
The mechanism of end-organ resistance to 1 alpha,25-dihydroxycholecalciferol in the common marmoset. 总被引:2,自引:0,他引:2 下载免费PDF全文
N Takahashi S Suda T Shinki N Horiuchi Y Shiina Y Tanioka H Koizumi T Suda 《The Biochemical journal》1985,227(2):555-563
The common marmoset, a New World monkey, requires a large amount of cholecalciferol (110 i.u./day per 100g body wt.) to maintain its normal growth. In a previous report, we demonstrated that the circulating levels of 1 alpha, 25-dihydroxycholecalciferol [1 alpha,25(OH)2D3] in the marmosets are much higher than those in rhesus monkeys and humans, but the marmosets are not hypercalcaemic [Shinki, Shiina, Takahashi, Tanioka, Koizumi & Suda (1983) Biochem. Biophys. Res. Commun. 14, 452-457]. To compare the effect of the daily intake of cholecalciferol, two rhesus monkeys were given a large amount of cholecalciferol (900 i.u./day per 100g body wt). Their serum levels of calcium, 25-hydroxycholecalciferol and 24R,25-dihydroxycholecalciferol were markedly elevated, but the serum 1 alpha,25(OH)2D3 levels remained within a range similar to those in the rhesus monkeys fed the normal diet (intake of cholecalciferol 5 i.u./day per 100g body wt). Intestinal cytosols prepared from both monkeys contained similar 3.5 S macromolecules to which 1 alpha,25(OH)2D3 was bound specifically. However, the cytosols from the marmosets contained only one-sixth as many 1 alpha,25(OH)2D3 receptors as those from the rhesus monkeys. Furthermore, the activity of the 1 alpha,25(OH)2D3-receptor complex in binding to DNA-cellulose was very low in the marmosets. These results suggest that the marmoset possesses an end-organ resistance to 1 alpha,25(OH)2D3 and is a useful animal model for studying the mechanism of vitamin D-dependent rickets, type II. 相似文献
9.
Immunoreactive dynorphin (I-dynorphin) was measured by radioimmunoassay in human cerebrospinal fluid (CSF). I-dynorphin concentration in CSF was 30 +/- 2 pg/ml. Sephadex G-25 column chromatography showed the main peak eluted at the position of dynorphin-(1-17). HPLC elution profile of this major peak from gel filtration showed a large peak corresponding to the position of dynorphin-(1-17) and small peaks corresponding to the positions of dynorphin-(1-13), dynorphin-(1-12) and other unknown peptides. 相似文献
10.
M Suda K Nakao T Yoshimasa Y Ikeda M Sakamoto N Yanaihara S Numa H Imura 《Life sciences》1983,32(24):2769-2775
The primary structure of the common precursor of porcine beta-neo-endorphin and dynorphin (preproenkephalin B) has shown the existence of a third leucine-enkephalin (leu-enkephalin) sequence with a C-terminal extension of 24 amino acids. This nonacosapeptide, named leumorphin, was approximately 70 times more potent than leu-enkephalin in inhibiting the contraction of the myenteric plexus-longitudinal muscle preparation of the guinea pig ileum. This action of leumorphin, like those of beta-neo-endorphin and dynorphin, was antagonized less effectively by naloxone than that of leu-enkephalin, but more effectively by Mr2266, an antagonist relatively specific for the kappa type opiate receptor. The inhibitory action of leumorphin or beta-neo-endorphin on the contraction of the guinea pig ileum muscle strip was reduced in a dose-dependent manner by pretreatment with dynorphin and vice versa. Leumorphin as well as beta-neo-endorphin and dynorphin inhibits the contraction of the rabbit vas deferens which is known to have only the kappa type opiate receptor. This action was also effectively antagonized by Mr2266. It is concluded that leumorphin has potent opioid activity and acts at the kappa receptor, like other opioid peptides derived from preproenkephalin B. 相似文献