全文获取类型
收费全文 | 3495篇 |
免费 | 181篇 |
国内免费 | 1篇 |
出版年
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 33篇 |
2020年 | 19篇 |
2019年 | 26篇 |
2018年 | 50篇 |
2017年 | 44篇 |
2016年 | 76篇 |
2015年 | 114篇 |
2014年 | 115篇 |
2013年 | 428篇 |
2012年 | 222篇 |
2011年 | 228篇 |
2010年 | 138篇 |
2009年 | 139篇 |
2008年 | 239篇 |
2007年 | 225篇 |
2006年 | 252篇 |
2005年 | 198篇 |
2004年 | 191篇 |
2003年 | 202篇 |
2002年 | 189篇 |
2001年 | 34篇 |
2000年 | 30篇 |
1999年 | 30篇 |
1998年 | 40篇 |
1997年 | 39篇 |
1996年 | 33篇 |
1995年 | 44篇 |
1994年 | 31篇 |
1993年 | 24篇 |
1992年 | 13篇 |
1991年 | 20篇 |
1990年 | 16篇 |
1989年 | 15篇 |
1988年 | 11篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 16篇 |
1981年 | 17篇 |
1980年 | 8篇 |
1979年 | 12篇 |
1978年 | 12篇 |
1977年 | 6篇 |
1976年 | 11篇 |
1974年 | 9篇 |
1973年 | 5篇 |
排序方式: 共有3677条查询结果,搜索用时 281 毫秒
101.
Masato Ohtani Toshiaki Kondo Naoki Tani Saneyoshi Ueno Leong S. Lee Kevin K. S. Ng Norwati Muhammad Reiner Finkeldey Mohamad Na'iem Sapto Indrioko Koichi Kamiya Ko Harada Bibian Diway Eyen Khoo Kensuke Kawamura Yoshihiko Tsumura 《Molecular ecology》2013,22(8):2264-2279
Tropical rainforests in South‐East Asia have been affected by climatic fluctuations during past glacial eras. To examine how the accompanying changes in land areas and temperature have affected the genetic properties of rainforest trees in the region, we investigated the phylogeographic patterns of a widespread dipterocarp species, Shorea leprosula. Two types of DNA markers were used: expressed sequence tag‐based simple sequence repeats and chloroplast DNA (cpDNA) sequence variations. Both sets of markers revealed clear genetic differentiation between populations in Borneo and those in the Malay Peninsula and Sumatra (Malay/Sumatra). However, in the south‐western part of Borneo, genetic admixture of the lineages was observed in the two marker types. Coalescent simulation based on cpDNA sequence variation suggested that the two lineages arose 0.28–0.09 million years before present and that following their divergence migration from Malay/Sumatra to Borneo strongly exceeded migration in the opposite direction. We conclude that the genetic structure of S. leprosula was largely formed during the middle Pleistocene and was subsequently modified by eastward migration across the subaerially exposed Sunda Shelf. 相似文献
102.
Shuuji Yamamoto Yasuji Minoda Koichi Yamada 《Bioscience, biotechnology, and biochemistry》2013,77(12):2719-2726
Substrate specificity of purified preparations of phytase from Asp, terreus was examined. The enzyme showed broad specificity. It was found that Asp, terreus produced only one kind of acid phosphatase and it had phytase activity.Effective materials for the enzyme formation were examined. The formation of the enzyme occurred only during times that mycelia was in contact with inositol.By differential centrifugation and electron-microscopic autoradiography, it was determined that inositol was incorporated into the mycelia and that it was located at almost the same point as where the active enzyme was located. 相似文献
103.
Yasushi Morinaga Shigeru Yamanaka Koichi Takinami 《Bioscience, biotechnology, and biochemistry》2013,77(9):2113-2114
In the higher plant, Arabidopsis thaliana, histidine-to-aspartate (His-to-Asp) phosphorelay signal transduction systems play crucial roles in propagation of environmental stimuli, including plant hormones. This plant has 11 sensor His-kinases, 5 histidine-containing phosphotransfer (HPt) factors (AHPs), and 20 response regulators (ARRs). To gain new insight into the functions of these phosphorelay components, their intracellular localization was examined with use of GFP-fusion proteins, constructed for certain representatives of HPt factors (AHP2) and type-A and type-B ARRs (ARR6/ARR7 and ARR10, respectively). The results showed that AHP2 is mainly located in the cytoplasmic space, while both the types of ARRs have an ability to enter preferentially into the nuclei, if not exclusively. Together with the results from an in vitro phosphorelay assay with AHP2 and ARRs, these results are discussed, in terms of a geneal framework of the Arabidopsis His-to-Asp phosphorelay network. 相似文献
104.
105.
Akio Kobayashi Akira Takemura Koichi Koshimizu Hiroshi Nagano Kazuyoshi Kawazu 《Bioscience, biotechnology, and biochemistry》2013,77(2):585-589
Three fungal trichothecenes, verrucarin A, roridin A and 8-β-hydroxyroridin E, were isolated as callus-initiating promoters from Myrothecium sp. 301. These trichothecenes promoted callus induction, synergistically coupled with a low concentration of 2,4-dichlorophenoxyacetic acid. 相似文献
106.
In the course of investigation of alicyclic hydrocarbon-utilizing microorganisms, five strains of ethylcyclohexane-utilizing bacteria were isolated from soil samples.Among those bacteria, the strain S6B1 that was identified as Alcaligenes faecalis, showed the best growth in shaking culture.The strain S6B1 was found to produce 4-ethylcyclohexanol from ethylcyclohexane.This substance separated from culture broth was purified and identified to be trans-4-ethylcyclohexanol by the use of NMR. 相似文献
107.
Yoshikazu Izumi Kuninori Sato Yoshiki Tani Koichi Ogata 《Bioscience, biotechnology, and biochemistry》2013,77(11):2683-2684
Vitamin B6 is synthesized by green Cytisus scoparius callus and green Phellodendron amurense callus cultured on Linsmaier and Skoog Agar-medium with 10?5m of ±-naphthaleneacetic acid (NAA) and 10?6 m of 6-benzyladenine (BA). Even when thiamine and inositol were omitted from this medium, the growth and vitamin B6 content of Cytisus scoparius callus did not change. Vitamin B6 contents of clones of the calluses varied and were unstable during long-term subculture. Clonal selection was repeated to obtain stable strains with high vitamin B6 content, and the vitamin B6 content of one strain of green Cytisus scoparius callus became 4-times higher than that of the green leaves. 相似文献
108.
Hideaki Yamada Osao Adachi Koichi Ogata 《Bioscience, biotechnology, and biochemistry》2013,77(2):117-123
The amine oxidase was found to be formed in mycelia of fungi when they were grown on monoamines or diamines as sole nitrogen sources. The maximal formation of enzyme was observed in the initial stage of growth, then the enzyme disappeared semilogarithmically. Other sources of nitrogen, such as ammonia, nitrate, urea and amino acids, were fully inactive for the enzyme formation. Furthermore, ammonia repressed the enzyme formation by fungi. The amine oxidase of fungi resembled in substrate specificity the monoamine oxidase of animal tissues. The enzyme oxidized preferentially aliphatic monoamines of C3–C6. Agmatine and histamine were also oxidized but in lower rates. Benzylamine was well oxidized by the enzymes of Aspergillus niger and Penicillium chrysogenum, but not by the enzymes of Monascus anka and Fusarium bulbigenum. Polyamines were not oxidized by the fungal enzymes. 相似文献
109.
Shuuji Yamamoto Yasuji Minoda Koichi Yamada 《Bioscience, biotechnology, and biochemistry》2013,77(12):2097-2103
Some chemical and physicochemical properties of the purified phytase preparation produced by Asp. terreus were investigated. From the results of the examination of amino acid analysis, it was suggested that there existed some components other than amino acids in the purified enzyme. Examination of the neutral sugar analysis, therefore, was made by gaschromatography, and it was found that the purified enzyme preparation contained mannose, galactose and a small amount of inositol.The molecular weight of the enzyme was found to be 214,000 by the Archibald method, and 2.2~2.3×105 by gel-filtration on a Sephadex G–200 column. It was found that by guanidine hydrochloride or by urea, the purified enzyme preparation was dissociated into only one kind of subunit. The native enzyme was supposed to be a homohexamer of the subunits whose molecular weight is 37,000. 相似文献
110.
Koichi Shimbayashi Toshio Yonemura 《Bioscience, biotechnology, and biochemistry》2013,77(11):1603-1609
A large amount of ammonia is produced in the rumen and some portion of the ammonia are absorbed into the portal blood through the rumen mucosa. Accordingly, it seems that ammonia detoxication is more necessary for the ruminant than for the non-ruminant. Activities of the urea cycle enzymes as principal instrument for ammonia detoxication in goat were investigated in this experiment.The activities of the urea cycle enzymes of goat were found to be very similar to those of rat reported by other authors. The activities of the urea cycle enzymes were affected by the protein level of diet. Administration of magnesium aspartate increased the activities of argininosuccinate synthetase and arginase, and had some effect on the concentrations of citrulline, aspartic acid, and urea in the liver. 相似文献