全文获取类型
收费全文 | 1758篇 |
免费 | 119篇 |
出版年
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 13篇 |
2018年 | 19篇 |
2017年 | 13篇 |
2016年 | 25篇 |
2015年 | 32篇 |
2014年 | 40篇 |
2013年 | 98篇 |
2012年 | 81篇 |
2011年 | 77篇 |
2010年 | 49篇 |
2009年 | 66篇 |
2008年 | 80篇 |
2007年 | 66篇 |
2006年 | 73篇 |
2005年 | 87篇 |
2004年 | 89篇 |
2003年 | 72篇 |
2002年 | 80篇 |
2001年 | 82篇 |
2000年 | 72篇 |
1999年 | 67篇 |
1998年 | 21篇 |
1997年 | 18篇 |
1996年 | 16篇 |
1995年 | 20篇 |
1994年 | 17篇 |
1993年 | 21篇 |
1992年 | 38篇 |
1991年 | 49篇 |
1990年 | 41篇 |
1989年 | 44篇 |
1988年 | 39篇 |
1987年 | 32篇 |
1986年 | 20篇 |
1985年 | 29篇 |
1984年 | 21篇 |
1983年 | 15篇 |
1982年 | 7篇 |
1981年 | 12篇 |
1980年 | 11篇 |
1979年 | 12篇 |
1978年 | 11篇 |
1977年 | 12篇 |
1976年 | 11篇 |
1975年 | 8篇 |
1974年 | 10篇 |
1973年 | 8篇 |
1969年 | 9篇 |
排序方式: 共有1877条查询结果,搜索用时 78 毫秒
91.
J S Allen K Matsunaga T Nakamura F Kitamura T Furukawa S S Hacisalihzade V M Sarich L Stark 《Human biology; an international record of research》1990,62(3):337-352
Smooth-pursuit eye-tracking dysfunction is a putative genetic trait marker for schizophrenia. In this study 88 Japanese schizophrenics from Kyushu and Okinawa were examined for the marker using precise high-resolution instrumentation: 76% of the schizophrenics from Kyushu and 89% of those from Okinawa had pursuit dysfunction. The presence of the culture-neutral smooth-pursuit marker for schizophrenia in Japan demonstrates that the etic concept "schizophrenia" is cross-culturally valid. Furthermore, the ubiquity of the marker in biologically and culturally diverse populations may indicate a limit on the extent of meaningful heterogeneity likely to be discovered within the condition. 相似文献
92.
H Shimizu H Tsuchie H Honma K Yoshida T Tsuruoka H Ushijima T Kitamura 《Japanese journal of medical science & biology》1990,43(3):75-87
The effect of N-(3-phenyl-2-propenyl)-1-deoxynojirimycin (ppDNM) on the lectin binding to HIV-1 glycoprotein was analyzed by using biotinylated lectins of various sugar specificities as probes. ppDNM potentially inhibited HIV-1-induced syncytium formation and viral infectivity of HIV-1 without cytotoxicity. The lectin binding assay showed that ppDNM treatment reduced Con A binding to gp120 of HIV-1. 相似文献
93.
K Kitamura K Kangawa K Tanaka H Matsuo 《Biochemical and biophysical research communications》1990,169(3):1164-1171
In the present purification of low molecular weight fractions (Mr: 2000-4000) containing basic peptides, twenty nmol of novel calmodulin binding peptide, possessing a potent affinity for calmodulin, was isolated from 18 kg of porcine brain. By analysis with gas phase sequencer, the sequence was determined to be APAEDLARYYSALRHYINLITRQRY. Carboxy terminus of the peptide was determined to be Tyr-NH2. The peptide was a carboxy terminal pentacosanepeptide of neuropeptide Y and was termed NPY-25. NPY-25 competitively inhibited the activation of cAMP-phosphodiesterase through CaM binding in a Ca++ dependent fashion, but did not inhibit the basal activity of cAMP phosphodiesterase. NPY-25 elicited a more potent activity than did neuropeptide Y. IC50 values of NPY-25 and Neuropeptide Y were 0.06 microM and 0.54 microM respectively. 相似文献
94.
The perineuronal extracellular matrix of the canine superior olivary nuclei was examined by the histochemical method. The extracellular matrix was stained with Alcian blue (pH 1.0 and 2.5), high iron diamine and ruthenium red. The staining intensity of Alcian blue in the extracellular matrix was remarkably reduced after chondroitinase ABC digestion but not after that of heparitinase or hyaluronidase. These results indicate that the extracellular matrix consists of proteoglycans and contains the chondroitin sulfate proteoglycan. 相似文献
95.
96.
Takehiko Watanabe Kazutaka Maeyama Atsushi Yamatodani Mitsuko Yamada Yukihiko Kitamura Hiroshi Wada 《Life sciences》1980,26(19):1569-1574
The histamine contents were very low in the whole bodies of various types of mutant mice (Wv/Wv, Wv/W, W/W), in which the number of mast cells was decreased, but the L-histidine decarboxylase activities in these mutant mice were not much lower than in control wild type mice. These findings suggest the presence of high histidine decarboxylase activity in cells other than mast cells. Histidine decarboxylase in the whole body of mice was difficult to assay, because the enzyme was rapidly destroyed by proteases, but inclusion of a protease inhibitor, such as Leupeptin, Antipain, Chymostatin, or Pepstatin in the assay mixture permitted the accurate assay of histidine decarboxylase in crude extracts. 相似文献
97.
Cells of Schizosaccharomyces pombe grown in the presence of aculeacin A, a peptide antibiotic, were lysed resulting the death of cells. Under high osmolarity, the cellular lysis induced by aculeacin A was considerably reduced. The use of synchronous-culture systems distinguished cell elongation from cell division revealed that the sites of aculeacin A-induced lysis on the fission yeast were the end(s) and the cell plate region, corresponded to the regions of the cell wall synthesis. Aculeacin A-resistant survivors exhibited morphological alterations which were swollen at one or both ends of the cell and appeared drumstick or dumbbel like; the wall of the bulge region was observed to be stained with a fluorescent brightener, as well as that of the cell plate region. These effects of aculeacin A are discussed as compared with effects of 2-deoxy-D-glucose. 相似文献
98.
A Kitamura Y Tanigawa S Okamoto Y Miyake M Shimoyama 《Biochimica et biophysica acta》1981,677(1):63-68
The effect of theophylline on poly(ADP-ribosyl)ation was investigated. The poly(ADP-ribose) synthetase activity in vitro was markedly reduced in the liver nuclei prepared from theophylline-treated chick embryo. This reduction was not due to the enzyme inhibition by theophylline contamination in the nuclear fraction. The hydroxyapatite column chromatographic analysis of [3H]adenosine-labelled poly(ADP-ribose)molecules formed in vivo revealed that the in vivo formation of poly(ADP-ribose)molecules was also decreased by theophylline administration. The theophylline-induced reduction of poly(ADP-ribose) synthesis was not due to either low NAD levels or to a decrease in the chain length of the poly(ADP-ribose) molecule, rather this reduction was derived from a decrease in the number of poly(ADP-ribose) molecule. Possible mechanisms related to reduction of poly(ADP-ribose) synthesis in vivo are discussed. 相似文献
99.
100.
Role of proton dissociation in the transport of cystine and glutamate in human diploid fibroblasts in culture 总被引:5,自引:0,他引:5
The effect of extracellular pH on the transport interaction of cystine and glutamate in cultured human diploid cells was examined over the pH range of 5.8-8.0. The initial rates of uptake of cystine increased with an increase in pH and glutamate potently inhibited the cystine uptake independently of pH. The uptake of glutamate was almost invariable within the pH range, but it was inhibited by cystine in a pH-dependent manner; the inhibition increased with an increase in pH. Regardless of pH, the uptake of cystine and glutamate was strongly inhibited by alpha-aminoadipate, alpha-aminopimelate, and homocysteate. From the pK values of cystine and other amino acids, it is suggested that cystine is transported in the same ionic form as is glutamate. 相似文献