全文获取类型
收费全文 | 1647篇 |
免费 | 95篇 |
专业分类
1742篇 |
出版年
2022年 | 7篇 |
2021年 | 11篇 |
2020年 | 14篇 |
2019年 | 9篇 |
2018年 | 11篇 |
2017年 | 14篇 |
2016年 | 19篇 |
2015年 | 35篇 |
2014年 | 47篇 |
2013年 | 142篇 |
2012年 | 79篇 |
2011年 | 100篇 |
2010年 | 48篇 |
2009年 | 57篇 |
2008年 | 85篇 |
2007年 | 85篇 |
2006年 | 87篇 |
2005年 | 77篇 |
2004年 | 80篇 |
2003年 | 65篇 |
2002年 | 60篇 |
2001年 | 41篇 |
2000年 | 67篇 |
1999年 | 46篇 |
1998年 | 16篇 |
1997年 | 14篇 |
1996年 | 19篇 |
1995年 | 18篇 |
1994年 | 9篇 |
1993年 | 16篇 |
1992年 | 30篇 |
1991年 | 33篇 |
1990年 | 30篇 |
1989年 | 33篇 |
1988年 | 30篇 |
1987年 | 30篇 |
1986年 | 19篇 |
1985年 | 22篇 |
1984年 | 20篇 |
1983年 | 16篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 10篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1969年 | 4篇 |
1968年 | 10篇 |
1966年 | 5篇 |
排序方式: 共有1742条查询结果,搜索用时 0 毫秒
81.
82.
Hiroshi Hakoyama Hiroka Fujimori Chiaki Okamoto Sakie Kodama 《Ecological Research》2016,31(2):153-153
Fishery sustainability and the extinction risk of the Japanese eel, Anguilla japonica, are of global concern. The landings of the Japanese eel in Japan comprise a large part of the landings in East Asia. This study provides a compiled dataset of the annual fisheries statistics of the Japanese eel in Japan for stock assessment. The Japanese government has been recording Japanese eel statistics annually since 1984 in five series of annual reports by conducting systematic questionnaire surveys of fisheries managers and associations; however, most of these data are stored in analog format. The key variables in the dataset include the harvest weight of eels, the harvest weight and number of seeds for aquaculture, the number of eels stocked, and the number of management entities engaged in the eel fishery. The levels of spatial aggregation of the variables include the site (river and lake), prefecture, inland and coastal waters, and total in Japan. We also incorporated location data (latitude and longitude) of the site and prefecture into the dataset. Eel harvest includes primarily yellow eels (late juvenile stage) and silver eels (mature stage). Seed harvest in inland waters includes glass eels (intermediate stage between leptocephalus and elver) and elvers (early juvenile stage). Seed harvest from coastal waters comprises glass eels. This dataset provides information to assess long-term trends in the Japanese eel population. 相似文献
83.
Takefumi Yamashita Eiichi Mizohata Satoru Nagatoishi Takahiro Watanabe Makoto Nakakido Hiroko Iwanari Yasuhiro Mochizuki Taisuke Nakayama Yuji Kado Yuki Yokota Hiroyoshi Matsumura Takeshi Kawamura Tatsuhiko Kodama Takao Hamakubo Tsuyoshi Inoue Hideaki Fujitani Kouhei Tsumoto 《Structure (London, England : 1993)》2019,27(3):519-527.e5
84.
Nagae M Tsuchiya A Katayama T Yamamoto K Wakatsuki S Kato R 《The Journal of biological chemistry》2007,282(25):18497-18509
1,2-alpha-L-fucosidase (AfcA), which hydrolyzes the glycosidic linkage of Fucalpha1-2Gal via an inverting mechanism, was recently isolated from Bifidobacterium bifidum and classified as the first member of the novel glycoside hydrolase family 95. To better understand the molecular mechanism of this enzyme, we determined the x-ray crystal structures of the AfcA catalytic (Fuc) domain in unliganded and complexed forms with deoxyfuconojirimycin (inhibitor), 2'-fucosyllactose (substrate), and L-fucose and lactose (products) at 1.12-2.10 A resolution. The AfcA Fuc domain is composed of four regions, an N-terminal beta region, a helical linker, an (alpha/alpha)6 helical barrel domain, and a C-terminal beta region, and this arrangement is similar to bacterial phosphorylases. In the complex structures, the ligands were buried in the central cavity of the helical barrel domain. Structural analyses in combination with mutational experiments revealed that the highly conserved Glu566 probably acts as a general acid catalyst. However, no carboxylic acid residue is found at the appropriate position for a general base catalyst. Instead, a water molecule stabilized by Asn423 in the substrate-bound complex is suitably located to perform a nucleophilic attack on the C1 atom of L-fucose moiety in 2'-fucosyllactose, and its location is nearly identical near the O1 atom of beta-L-fucose in the products-bound complex. Based on these data, we propose and discuss a novel catalytic reaction mechanism of AfcA. 相似文献
85.
Kiyosaki T Matsumoto I Asakura T Funaki J Kuroda M Misaka T Arai S Abe K 《The FEBS journal》2007,274(8):1908-1917
We cloned a new cysteine proteinase of wheat seed origin, which hydrolyzed the storage protein gliadin almost specifically, and was named gliadain. Gliadain mRNA was expressed 1 day after the start of seed imbibition, and showed a gradual increase thereafter. Gliadain expression was suppressed when uniconazol, a gibberellin synthesis inhibitor, was added to germinating seeds. Histochemical detection with anti-gliadain serum indicated that gliadain was present in the aleurone layer and also that its expression intensity increased in sites nearer the embryo. The enzymological characteristics of gliadain were investigated using recombinant glutathione S-transferase (GST)-progliadain fusion protein produced in Escherichia coli. The GST-progliadain almost specifically digested gliadin into low molecular mass peptides. These results indicate that gliadain is produced via gibberellin-mediated gene activation in aleurone cells and secreted into the endosperm to digest its storage proteins. Enzymologically, the GST-progliadain hydrolyzed benzyloxycarbonyl-Phe-Arg-7-amino-4-methylcoumarin (Z-Phe-Arg-NH(2)-Mec) at K(m) = 9.5 microm, which is equivalent to the K(m) value for hydrolysis of this substrate by cathepsin L. Hydrolysis was inhibited by two wheat cystatins, WC1 and WC4, with IC(50) values of 1.7 x 10(-8) and 5.0 x 10(-8) m, respectively. These values are comparable with those found for GST-progliadain inhibition by E-64 and egg-white cystatin, and are consistent with the possibility that, in germinating wheat seeds, gliadain is under the control of intrinsic cystatins. 相似文献
86.
Tanida Kotomi Shimada Mihoko Khor Seik-Soon Toyoda Hiromi Kato Kayoko Kotorii Nozomu Kotorii Tatayu Ariyoshi Yu Kato Takao Hiejima Hiroshi Ozone Motohiro Uchimura Naohisa Ikegami Azusa Kume Kazuhiko Kanbayashi Takashi Imanishi Aya Kamei Yuichi Hida Akiko Wada Yamato Kuroda Kenji Miyamoto Masayuki Hirata Koichi Takami Masanori Yamada Naoto Okawa Masako Omata Naoto Kondo Hideaki Kodama Tohru Inoue Yuichi Mishima Kazuo Honda Makoto Tokunaga Katsushi Miyagawa Taku 《Sleep and biological rhythms》2022,20(1):137-148
Sleep and Biological Rhythms - Idiopathic hypersomnia (IH) is a rare sleep disorder characterized by excessive daytime sleepiness, great difficulty upon awakening, and prolonged sleep time. In... 相似文献
87.
Yasuno K Yamazaki T Tanaka Y Kodama TS Matsugami A Katahira M Ishihama A Kyogoku Y 《Journal of molecular biology》2001,306(2):213-225
88.
The purpose of this study was to validate the self-reported body height and weight of adult Japanese women. The subjects were women, aged 20-42 years, who participated in a survey on eating disorders in women in 1995. Physically measured height and weight data were obtained for 368 (89.8%) of the 469 women who self-reported their height and weight. The report-based heights and weights were compared with the measured values. The correlation coefficients for height and weight were 0.990 and 0.963 (p < 0.0001), respectively. Mean reported height was 0.1 cm shorter and mean reported weight 0.2 kg lighter than the measured values. Shorter women tended to report a taller height than their actual height, and heavier women to report a lower weight than their actual weight. Despite these limitations, the self-reported heights and weights of adult Japanese women were precise and accurate, and their use in epidemiological surveys is considered acceptable. 相似文献
89.
A novel strategy for the maximum production of a biodegradable copolymer, poly(3-hydroxybutyric-co-hydroxyvaleric) acid, P(HB-co-HV), was developed, based on the kinetic parameters obtained from fed-batch culture experiments of Alcaligenes eutrophus. The effects of various culture conditions such as mole ratio of carbon:nitrogen in feed medium (C/N); total fatty acids concentrations; and addition ratio of fatty acids on cultivation properties such as the specific rates of cell formation, mu (h-1), P(HB-co-HV) production, rho[g.P(HB-co-HV)/g.cell/h], production yield from fatty acids [g.P(HB-co-HV)/g.fatty acid], and mole fraction of monomeric units in the copolymer [mol.(HV)/{mol.(HB) + mol.(HV)}], were investigated. When nitrogen supply was sufficient for cell growth; that is, C/N (mol.nitrogen atom/mol.carbon atom) was low, mu was high, but rho and the production yield were low, because fatty acids were used mainly for energy formation and anabolic reactions in the cells. On the other hand, when nitrogen supply was limited for cell growth-that is, C/N was high-rho was high. The highest value of rho was obtained when C/N was 75. As the mole ratio of valeric acid (VA) to butyric acid (BA) in the feed medium was increased, the mole fraction of HV units in P(HB-co-HV) increased linearly. When the ratio of BA to VA in the feed medium was kept at a constant value, but C/N was increased, the mole fraction of HV units decreased. In particular, when C/N was >12, the mole fraction of HV units decreased linearly as C/N increased. When VA was utilized as the sole carbon source and C/N was fixed at 4, P(HB-co-HV) with the highest mole fraction of HV units (67 mol%) was achieved. From these results, it was shown that both C/N and the mole ratio of BA to VA in the feed medium should be well controlled for an optimal production of P(HB-co-HV) with the desired value of the mole fraction of HV units. When the addition ratio of butyric acid was 50 wt% of total fatty acids, a maximum production strategy for P(HB-co-HV) was developed and realized experimentally, which was based on a model of the relationship between mu and rho. 相似文献
90.