全文获取类型
收费全文 | 980篇 |
免费 | 63篇 |
出版年
2022年 | 7篇 |
2021年 | 9篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 15篇 |
2015年 | 20篇 |
2014年 | 27篇 |
2013年 | 55篇 |
2012年 | 55篇 |
2011年 | 59篇 |
2010年 | 31篇 |
2009年 | 21篇 |
2008年 | 56篇 |
2007年 | 62篇 |
2006年 | 76篇 |
2005年 | 49篇 |
2004年 | 42篇 |
2003年 | 40篇 |
2002年 | 62篇 |
2001年 | 42篇 |
2000年 | 33篇 |
1999年 | 40篇 |
1998年 | 8篇 |
1997年 | 13篇 |
1996年 | 12篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 18篇 |
1991年 | 14篇 |
1990年 | 12篇 |
1989年 | 19篇 |
1988年 | 13篇 |
1987年 | 7篇 |
1986年 | 12篇 |
1985年 | 13篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 8篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1970年 | 3篇 |
排序方式: 共有1043条查询结果,搜索用时 250 毫秒
31.
Effects of 3-(3, 4-dichlorophenyl)-l, 1-dimethylurea (DCMU)on photosynthetic oxygen evolution, respiratory oxygen uptake,phototactic response and swimming rate in Cryptomonas sp. weredetermined and compared. Photosynthetic oxygen evolution wascompletely inhibited in the presence of 105 M DCMU. Thetreatment did not significantly affect the rates of respiratoryoxygen uptake, phototaxis, and swimming, indicating that directparticipation of photosynthesis in the phototaxis of this algacan be ruled out. Wavelength dependency of photosynthetic oxygen evolution wasalso determined in the range of 560 to 700 nm. The rate of photosyntheticoxygen evolution at 680 nm was as high as that at 560 nm, butno phototactic activity was seen at 680 nm although it was maximumat 560 nm. This is consistent with the above conclusion. (Received February 16, 1976; ) 相似文献
32.
Using the paper disc-agar plate method, a number of fatty and related acids have been tested for tested activity for inhibiting the growth of Chlorella pyrenoidosa Chick. Of the saturated acids, a peak in growth inhibiting activity wax observed in the C7–C12 range, where inhibition wax observed when solutions down to 0.02 M were applied to the discs. Most of the unsaturated acids tested showed greater inhibition than did the corresponding saturated acids. Acrylic acid showed detectable inhibition at 0.001 M concentration. 相似文献
33.
Cdc14 belongs to a dual-specificity phosphatase family highly conserved through evolution that preferentially reverses CDK (Cyclin dependent kinases) –dependent phosphorylation events. In the yeast Saccharomyces cerevisiae, Cdc14 is an essential regulator of late mitotic events and exit from mitosis by counteracting CDK activity at the end of mitosis. However, many studies have shown that Cdc14 is dispensable for exiting mitosis in all other model systems analyzed. In fission yeast, the Cdc14 homologue Flp1/Clp1 regulates the stability of the mitotic inducer Cdc25 at the end of mitosis to ensure Cdk1 inactivation before cytokinesis. We have recently reported that human Cdc14A, the Cdc14 isoform located at the centrosomes during interphase, down-regulates Cdc25 activity at the G2/M transition to prevent premature activation of Cdk1-Cyclin B1 complexes and untimely entry into mitosis. Here we speculate about new molecular mechanisms for Cdc14A and discuss the current evidence suggesting that Cdc14 phosphatase plays a role in cell cycle control in higher eukaryotes. 相似文献
34.
35.
36.
Kotarosumitomo Nakayama Kenta Moriwaki Taku Imai Shinichiro Shinzaki Yoshihiro Kamada Kohei Murata Eiji Miyoshi 《PloS one》2013,8(7)
Fucosylation is a crucial oligosaccharide modification in cancer. The known function of fucosylation in cancer is to mediate metastasis through selectin ligand-dependent processes. Previously, we found complete loss of fucosylation in the colon cancer cell line HCT116 due to a mutation in the GDP-fucose synthetic enzyme, GDP-mannose-4,6-dehydratase (GMDS). Loss of fucosylation led to escape of cancer cells from tumor immune surveillance followed by tumor progression and metastasis, suggesting a novel function of fucosylation in tumor progression pathway. In the present study, we investigated the frequency of GMDS mutation in a number of clinical colorectal cancer tissue samples: 81 samples of primary colorectal cancer tissue and 39 samples of metastatic lesion including liver and lymph node. Four types of deletion mutation in GMDS were identified in original cancer tissues as well as metastatic lesions. The frequency of GMDS mutation was slightly higher in metastatic lesions (12.8%, 5/39 samples) than in original cancer tissues (8.6%, 7/81 samples). No mutation of the GMDS gene was observed in normal colon tissues surrounding cancer tissues, suggesting that the mutation is somatic rather than in the germline. Immunohistochemical analysis revealed complete loss of fucosylation in three cases of cancer tissue. All three cases had GMDS mutation. In one of three cases, loss of fucosylation was observed in only metastatic lesion, but not its original colon cancer tissue. These data demonstrate involvement of GMDS mutation in the progression of colorectal cancer. 相似文献
37.
Katayama Kazuhiro Hosui Atsushi Sakai Yoshiyuki Itou Minoru Matsuzaki Yasushi Takamori Yoriyuki Hosho Keiko Tsuru Tomomi Takikawa Yasuhiro Michitaka Kojiro Ogawa Eishin Miyoshi Yoko Ito Toshifumi Ida Shinobu Hamada Izumi Miyoshi Katsunori Kodama Hiroko Takehara Tetsuo 《Biological trace element research》2020,195(1):71-81
Biological Trace Element Research - The essential trace element zinc maintains liver functions. Liver diseases can alter overall zinc concentrations, and hypozincemia is associated with various... 相似文献
38.
Masakazu Atobe Kenji Naganuma Masashi Kawanishi Akifumi Morimoto Ken-ichi Kasahara Shigeki Ohashi Hiroko Suzuki Takahiko Hayashi Shiro Miyoshi 《Bioorganic & medicinal chemistry letters》2013,23(22):6064-6067
We describe a medicinal chemistry approach to generate a series of 2-(1H-pyrazol-1-yl)thiazole compounds that act as selective EP1 receptor antagonists. The obtained results suggest that compound 12 provides the best EP1 receptor antagonist activity and demonstrates good oral pharmacokinetics. 相似文献
39.
Kazuyuki Maekawa Yasutaka Miyoshi Kenshiro Tsuru 《Bioscience, biotechnology, and biochemistry》2013,77(10):1951-1956
Dextran was subjected to oxidative scission by periodate, followed by ring closure with nitromethane to form nitrodextran. The nitro group attached to the ring was reduced by LiAlH4 to yield amino-polysaccharide of which the molecular weight was about 10,000. It became clear that nitrodextran consisted of 3-deoxy-3-nitro-mannopyranoside, -glucopyranoside, -galactopyranoside and -talopyranoside and their molar ratio was 6: 5: 1: 2 as determined by column Chromatographic separation and gas Chromatographic analysis of the methanolyzate of nitro-dextran. 相似文献
40.
Yuji Urabe Muneji Miyoshi Kazuo Matsumoto 《Bioscience, biotechnology, and biochemistry》2013,77(5):1085-1090
The chlorinolysis of l-methionine methyl ester hydrochloride with molecular chlorine was carried out under various conditions, resulting in methyl l-2-amino-4,4,4-trichlorobutanoate and methyl l-2-amino-3,4,4,4-tetrachlorobutanoate which were isolated as N-benzoyl and N-carbobenzoxy derivatives. The chlorinolysis of N-acylmethionine ester and methionine sulfoxide ester proceeded also without cleavage of the N-protecting group to give the same products as above. However, the reaction of methionine sulfone derivative with chlorine did not proceed in the same conditions.It was proved that the resulting polychloroamino acid derivatives are optically pure. The possible chlorinolysis mechanism was also proposed. 相似文献