全文获取类型
收费全文 | 2001篇 |
免费 | 124篇 |
国内免费 | 1篇 |
专业分类
2126篇 |
出版年
2022年 | 10篇 |
2021年 | 15篇 |
2020年 | 15篇 |
2019年 | 9篇 |
2018年 | 22篇 |
2017年 | 26篇 |
2016年 | 24篇 |
2015年 | 48篇 |
2014年 | 78篇 |
2013年 | 176篇 |
2012年 | 84篇 |
2011年 | 99篇 |
2010年 | 57篇 |
2009年 | 60篇 |
2008年 | 104篇 |
2007年 | 111篇 |
2006年 | 108篇 |
2005年 | 105篇 |
2004年 | 112篇 |
2003年 | 93篇 |
2002年 | 120篇 |
2001年 | 58篇 |
2000年 | 44篇 |
1999年 | 31篇 |
1998年 | 25篇 |
1997年 | 17篇 |
1996年 | 22篇 |
1995年 | 16篇 |
1994年 | 18篇 |
1993年 | 25篇 |
1992年 | 31篇 |
1991年 | 29篇 |
1990年 | 35篇 |
1989年 | 46篇 |
1988年 | 23篇 |
1987年 | 26篇 |
1986年 | 19篇 |
1985年 | 16篇 |
1984年 | 23篇 |
1983年 | 18篇 |
1982年 | 16篇 |
1981年 | 12篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1978年 | 10篇 |
1976年 | 7篇 |
1975年 | 11篇 |
1974年 | 7篇 |
1968年 | 6篇 |
1967年 | 6篇 |
排序方式: 共有2126条查询结果,搜索用时 15 毫秒
1.
2.
3.
M Kurono Y Hirachi Y Kato Y Toda N Takemasa S Kotani T Takahashi I Tadokoro 《Biken journal》1983,26(3):103-111
Intergenus cell fusion of prokaryotic bacteria was demonstrated for the first time; namely, fusion products doubly resistant to streptomycin and tetracycline were produced by polyethylene glycol treatment of a mixture of the streptomycin-resistant L-form of Pseudomonas aeruginosa and tetracycline-resistant L-form of Escherichia coli. 相似文献
4.
The primary structure of human Rieske iron-sulfur protein of mitochondrial cytochrome bc1 complex deduced from cDNA analysis 总被引:2,自引:0,他引:2
We isolated a cDNA encoding human Rieske Fe-S protein of mitochondrial cytochrome bc1 complex from a fibroblast cDNA library by colony hybridization. The cDNA contains the nucleotide sequence encoding all of the amino acids (274 residues) comprising the putative precursor to the protein. Based on the known amino acid sequence of bovine Rieske Fe-S protein, the N-terminal extension sequence is presumed to be composed of 78 amino acids with a molecular weight of 8053. The mature protein consists of the same number of amino acid residues as that of its rat and bovine counterparts, having a homology of about 92% with the latter. 相似文献
5.
Hohzoh Kiyohara Toshiro Watanabe Junko Imai Noboru Takizawa Takashi Hatta Kazutaka Nagao Akira Yamamoto 《Applied microbiology and biotechnology》1990,33(6):671-676
Summary To breed industrially useful strains of a slow-growing, red-pigment-producing strain ofMonascus anka, protoplasts ofM. anka MAK1 (arg) andAspergillus oryzae AOK1 (met, thr) were fused. A mixture of protoplasts prepared from mycelia ofM. anka MAK1 treated with 2% Usukizyme and ofA. oryzae AOK1 treated with 2% Usukizyme and 0.2% NovoZym 234 was incubated with 30% (w/v) polyethylene glycol no. 6000. Heterokaryon fusants complementing the auxotrophies of both mutants were isolated on minimal medium, but segregated into red (MAK1) and white (AOK1) sectors after being cultured on a complete medium. After irradiation with UV light, the fusants gave stable heterozygous diploids that formed long white hyphae. These diploids, which had twice as much DNA in the nucleus as their parents, grew more rapidly than the parent strain YZT1, and produced ethanol earlier than the parents. Production of amylase, protease, and kojic acid by the fusants was intermediate in amount between that of the two parents. 相似文献
6.
Koichi Rikimaru Hitomi Toda Noriko Tachikawa Nobuyuki Kamata Shoji Enomoto 《In vitro cellular & developmental biology. Plant》1990,26(9):849-856
Summary A novel protein-free synthetic medium has been developed for the culture of human squamous cell carcinoma cells. This medium,
designated PF86-1, supports the serial subcultivation of six out of nine human squamous cell carcinoma cell lines in a protein-free,
chemically defined condition without the adapting culture from serum-containing conditions. These cell lines growing in PF86-1
exhibited nearly equal potency to grow in massive culture without noticeable changes in morphology but presented a significantly
decreased level of colony forming efficiency when compared with the cells cultured in serum-containing media, suggesting the
implication of some autocrine mechanism. Interestingly, this medium supported the growth of normal human squamous cells of
oral mucosa and skin for more than 2 mo. in the primary explant culture in spite of high levels of calcium ion concentration,
where the overgrowth of fibroblasts as contaminant was not observed. These results suggest that PF86-1 supports the growth
of cells derived from epidermal tissues selectively and provides the same defined condition for growth of malignant and nonmalignant
human squamous cells. It seems, therefore, that PF86-1 allows investigations on the products of squamous cell carcinoma cells
or on the differences of growth mechanisms between normal and neoplastic human squamous cells. 相似文献
7.
8.
9.
10.
The complete amino acid sequence of calmodulin from Euglena gracilis was determined by isolation and sequence analyses of peptides derived from calmodulin by digestion with trypsin and Staphylococcus aureus V8 protease. Euglena calmodulin consists of 148 amino acid residues; it lacks tryptophan and cysteine and contains one tyrosine, three histidine and two NE-trimethyllysine residues/molecule of the protein. Its N-terminus was blocked with an acetyl group and C-terminal lysine was trimethylated. Euglena calmodulin is the first calmodulin so far examined in which the C-terminal lysine is trimethylated. The comparison of amino acid sequences between Euglena and human brain calmodulins indicated 17 amino acid substitutions in Euglena calmodulin. 相似文献