全文获取类型
收费全文 | 2210篇 |
免费 | 103篇 |
国内免费 | 1篇 |
出版年
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 24篇 |
2020年 | 11篇 |
2019年 | 22篇 |
2018年 | 38篇 |
2017年 | 39篇 |
2016年 | 45篇 |
2015年 | 71篇 |
2014年 | 72篇 |
2013年 | 161篇 |
2012年 | 155篇 |
2011年 | 165篇 |
2010年 | 100篇 |
2009年 | 75篇 |
2008年 | 125篇 |
2007年 | 130篇 |
2006年 | 119篇 |
2005年 | 120篇 |
2004年 | 114篇 |
2003年 | 102篇 |
2002年 | 116篇 |
2001年 | 21篇 |
2000年 | 38篇 |
1999年 | 34篇 |
1998年 | 30篇 |
1997年 | 21篇 |
1996年 | 15篇 |
1995年 | 17篇 |
1994年 | 25篇 |
1993年 | 22篇 |
1992年 | 19篇 |
1991年 | 24篇 |
1990年 | 20篇 |
1989年 | 25篇 |
1988年 | 17篇 |
1987年 | 20篇 |
1986年 | 15篇 |
1985年 | 14篇 |
1984年 | 16篇 |
1983年 | 10篇 |
1982年 | 13篇 |
1980年 | 8篇 |
1979年 | 9篇 |
1978年 | 7篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 8篇 |
1973年 | 5篇 |
1969年 | 5篇 |
排序方式: 共有2314条查询结果,搜索用时 15 毫秒
81.
82.
Hirokazu Matsui Seiya Chiba Tokuji Shimomura Nobuyuki Takahashi 《Bioscience, biotechnology, and biochemistry》2013,77(11):2239-2240
Hen lysozyme modified with histamine (HML) and Japanese quail lysozyme (JQL) were treated with immobilized metal ion affinity chromatography to analyze the states of their imidazole groups. When Ni(II) was used as the metal ion immobilized, JQL was strongly retained in a Ni(II)-chelating Sepharose column, while hen lysozyme and HML were hardly retained in the same column. All of these lysozymes have a histidine imidazole group at the 15th position, while JQL has an additional histidine imidazole group at the 103rd position and HML has an additional imidazole group covalently attached to Asp101. Thus, I concluded that the imidazole group at the 103rd position of JQL is exposed to the solvent and recognized by the metal ion, but that the imidazole group attached to Asp101 in HML is localized to a hydrophobic region and not recognized by the metal ion. 相似文献
83.
Makoto Kiso Mitsuru Maeda Norio Kurihara Minoru Nakajima 《Bioscience, biotechnology, and biochemistry》2013,77(2):459-461
Meso-(1245/36)-1,2,4,5,6-pentachloro-3-methylthiocyclohexane, and (124/356)-1,2,4,5,6-pentachloro-3-methylthio and ethylthiocyclohexanes were prepared from (1234/56)-1,4,5,6-tetrachloro-2,3-epoxycyclohexane (α-BTC cis-epoxide). 相似文献
84.
A new procedure which involves 1-trichloroacetyl sugars as the starting material has been developed for the synthesis of purine nucleosides. 7-β-d-Glucopyranosyl-, 7-β-d-xylopyranosyl-, 7-β-d-ribopyranosyl-theophylline, 9-(tetra-O-acetyl-β-d-glucopyranosyl)-2,6,8-trichloropurine and 9-β-d-glucopyranosyl adenine were prepared in good yields by the reaction in fusion of purine bases with 1-trichloroacetyl sugars, using zinc chloride, p-toluenesulfonic acid, or ethyl polyphosphate as catalyst. 9-d-Ribofuranosyl adenine was also prepared by the same procedures, although the anomeric configuration of the compound is not yet definite. The effect of catalysts on the yields of purine nucleosides is discussed. 相似文献
85.
Zen-ichiro Hamauzu Yukio Kamazuka Hirokazu Kanazawa Daizo Yonezawa 《Bioscience, biotechnology, and biochemistry》2013,77(8):1527-1531
Reduced and cyanoethylated glutenin was fractionated into three fractions (F I, F II and F III) by gel filtration on Sephadex G–100 in 0.1 m acetic acid. The molecular weight determination was made with these three fractions by sedimentation equilibrium in 6.5 m guanidine hydrochloride containing 0.01 m acetic acid. The molecular weight obtained was 44,000 for F II, and 32,000 for F III. F I showed a distribution of molecular weight due to the aggregation. The average molecular weight of F I was 52,000, being 27,000 at the meniscus and 98,000 at the bottom. The estimation of molecular weight by SDS–PAGE* gave overestimated values for glutenin polypeptides, as was already reported for gliadin. 相似文献
86.
Yuzuru Sanemitsu Norio Kurihara Minoru Nakajima G. E. McCasland L. F. Johnson L. C. Carey 《Bioscience, biotechnology, and biochemistry》2013,77(5):845-857
Two diastereomers of 6-bromo-1, 2, 3, 4, 5-pentachlorocyclohexane were synthesized from the dl (36/45)-diastereomer of 3, 4, 5, 6-tetrachlorocyclohexene (α-BTC) and the dl (346/5)-diastereomer (γ-BTC) by several stepwise routes. Both of these new products were shown to have the configuration of lindane by NMR studies at 300 MHz and by the synthetic routes. Three diastereomers of 6-bromo-3, 4, 5-trichlorocyclohexene were also prepared and the configurations determined partly by means of 300 MHz NMR. 相似文献
87.
Hisao Shibata Daikichi Nishimura Norio Kurihara Minoru Nakajima 《Bioscience, biotechnology, and biochemistry》2013,77(8):1002-1005
From 2,3,4,6-tetra-O-benzoyl-α-d-mannopyranosyl bromide by the Königs-Knorr reaction, α-d-mannos ides of (+)- and (?)-N-carbobenzoxy-trans-2-amino-cyclohexanol and 3-bromo-3-deoxy-1,2;4,5-di-O-isopropylidene-muco-inositol were synthesized. 相似文献
88.
Norio Kurihara Takashi Kurokawa Hiroshi Naka Minoru Nakajima 《Bioscience, biotechnology, and biochemistry》2013,77(8):1186-1969
Diacetyl-trans-aminodeoxybenzeneglycol (trans-1-acetamido-2-acetoxy-cyclohexadiene-3, 5) was synthesized by starting from α-B. T. C.-cis-diol2) through its dehydrochlorination, NaN3 treatment, reduction, and then dehalogenation with zinc. During NaN3 treatment, the formation of some diazido compounds was also observed. 相似文献
89.
Ki-Sung Kim Yuichiro Arima Taro Kitazawa Koichi Nishiyama Rieko Asai Yasunobu Uchijima Takahiro Sato Giovanni Levi Sachiko Kitanaka Takashi Igarashi Yukiko Kurihara Hiroki Kurihara 《Mechanisms of development》2013,130(11-12):553-566
Endothelin-1 (Edn1), originally identified as a vasoconstrictor peptide, is involved in the development of cranial/cardiac neural crest-derived tissues and organs. In craniofacial development, Edn1 binds to Endothelin type-A receptor (Ednra) to induce homeobox genes Dlx5/Dlx6 and determines the mandibular identity in the first pharyngeal arch. However, it remains unsolved whether this pathway is also critical for pharyngeal arch artery development to form thoracic arteries. Here, we show that the Edn1/Ednra signaling is involved in pharyngeal artery development by controlling the fate of neural crest cells through a Dlx5/Dlx6-independent mechanism. Edn1 and Ednra knock-out mice demonstrate abnormalities in pharyngeal arch artery patterning, which include persistent first and second pharyngeal arteries, resulting in additional branches from common carotid arteries. Neural crest cell labeling with Wnt1-Cre transgene and immunostaining for smooth muscle cell markers revealed that neural crest cells abnormally differentiate into smooth muscle cells at the first and second pharyngeal arteries of Ednra knock-out embryos. By contrast, Dlx5/Dlx6 knockout little affect the development of pharyngeal arch arteries and coronary arteries, the latter of which is also contributed by neural crest cells through an Edn-dependent mechanism. These findings indicate that the Edn1/Ednra signaling regulates neural crest differentiation to ensure the proper patterning of pharyngeal arch arteries, which is independent of the regional identification of the pharyngeal arches along the dorsoventral axis mediated by Dlx5/Dlx6. 相似文献
90.
Hirokazu Toju Satoshi Yamamoto Hirotoshi Sato Akifumi S. Tanabe Gregory S. Gilbert Kohmei Kadowaki 《Ecology and evolution》2013,3(5):1281-1293
In terrestrial ecosystems, plant roots are colonized by various clades of mycorrhizal and endophytic fungi. Focused on the root systems of an oak‐dominated temperate forest in Japan, we used 454 pyrosequencing to explore how phylogenetically diverse fungi constitute an ecological community of multiple ecotypes. In total, 345 operational taxonomic units (OTUs) of fungi were found from 159 terminal‐root samples from 12 plant species occurring in the forest. Due to the dominance of an oak species (Quercus serrata), diverse ectomycorrhizal clades such as Russula, Lactarius, Cortinarius, Tomentella, Amanita, Boletus, and Cenococcum were observed. Unexpectedly, the root‐associated fungal community was dominated by root‐endophytic ascomycetes in Helotiales, Chaetothyriales, and Rhytismatales. Overall, 55.3% of root samples were colonized by both the commonly observed ascomycetes and ectomycorrhizal fungi; 75.0% of the root samples of the dominant Q. serrata were so cocolonized. Overall, this study revealed that root‐associated fungal communities of oak‐dominated temperate forests were dominated not only by ectomycorrhizal fungi but also by diverse root endophytes and that potential ecological interactions between the two ecotypes may be important to understand the complex assembly processes of belowground fungal communities. 相似文献