全文获取类型
收费全文 | 720篇 |
免费 | 49篇 |
国内免费 | 1篇 |
出版年
2022年 | 3篇 |
2021年 | 8篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 11篇 |
2014年 | 15篇 |
2013年 | 46篇 |
2012年 | 27篇 |
2011年 | 30篇 |
2010年 | 21篇 |
2009年 | 18篇 |
2008年 | 36篇 |
2007年 | 29篇 |
2006年 | 50篇 |
2005年 | 43篇 |
2004年 | 45篇 |
2003年 | 47篇 |
2002年 | 42篇 |
2001年 | 15篇 |
2000年 | 23篇 |
1999年 | 16篇 |
1998年 | 15篇 |
1997年 | 10篇 |
1996年 | 15篇 |
1995年 | 5篇 |
1994年 | 14篇 |
1993年 | 5篇 |
1992年 | 15篇 |
1991年 | 12篇 |
1990年 | 14篇 |
1989年 | 10篇 |
1988年 | 11篇 |
1987年 | 10篇 |
1986年 | 14篇 |
1985年 | 7篇 |
1983年 | 10篇 |
1982年 | 3篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1971年 | 4篇 |
1969年 | 2篇 |
排序方式: 共有770条查询结果,搜索用时 15 毫秒
21.
Sumiko Narise 《Biochemical genetics》1979,17(5-6):433-444
Two allozymes (MDHf and MDHs) of cytoplasmic malate dehydrogenase of Drosophila virilis were partially purified and their biochemical properties were compared. MDHf has a pH optimum of 9.75 and MDHs one of 9.25 for malate oxidation. Optimal pH for oxaloacetate reduction is 6.75 and 8.0 for MDHf and MDHs, respectively. The Km value for oxaloacetate of MDHs is approximately twice as that of MDHf. No differences were found with respect to thermostability and Km's for malate, NAD+, or NADH. These results are discussed in terms of the physiological role of cytoplasmic malate dehydrogenase of D. virilis.This work was supported in part by grants from the Ministry of Education, Japan, Nos. 134050 and 154205. 相似文献
22.
The structure of the heme environment of horse heart ferric cytochrome c was examined in the presence of various nitrogenous bases at several temperatures with the aid of hyperfine shifted proton NMR spectra at 220 MHz. The resonance positions and line widths of the signals for the peripheral methyl groups of the heme exhibited distinctive features of its low-spin state characteristic of each external ligand. In the imidazole complex of ferric cytochrome c, remarkable line sharpening of the heme-linked proton signals was encountered on raising the temperature. This may be related to the apoprotein perturbation on the binding of external ligand to the heme iron. These spectral peculiarities were discussed in relation to the electronic structure of the heme, the basicity of the external ligand and the van der Waals contact interaction between heme side chains and apoprotein. 相似文献
23.
Dicoumarol, an antagonist of vitamin K, not only promoted theflower-inducing activity of vitamin K5, but also induced floweringin Lemna paucicostata when added alone to the medium. The flower-inducingactivity of dicoumarol was comparable to that of benzoic acidand could be greatly intensified by simultaneous applicationof benzyladenine as was the case with benzoic acid. Warfarin,another antagonist of vitamin K, did not induce flowering. 4-Hydroxycoumarin, a component of dicoumarol, was also active,but coumarin and 7-hydroxycoumarin were not. Dicoumarol hadonly a slight flower-inducing activity for strains 441 and 6746under continuous light, but had a strong flower-promoting effectunder a near critical photoperiod. That is, the effect of dicoumarolwas daylength-dependent. (Received April 22, 1985; Accepted August 21, 1985) 相似文献
24.
Sumiko Hara Chisato Kaneko Hiroatsu Matsumoto Takeshi Nishino Tadao Takeuchi Takeo Mori 《Nucleosides, nucleotides & nucleic acids》2013,32(2-4):571-582
Abstract Novel β-D-ribofuranosides having a 5-substituted imidazo [4,5-d] [1,3]thiazine ring, including the S6-congener 3 of oxanosine 2, were synthesized for screening their anticancer and antiviral activities. 相似文献
25.
Cytotechnology - Bone mass is regulated by osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Osteoporosis is a bone metabolism disorder in which bone mass decreases due to... 相似文献
26.
27.
Shota Tanifuji Megumi Funakoshi-Tago Fumihito Ueda Tadashi Kasahara Sumiko Mochida 《The Journal of biological chemistry》2013,288(26):19050-19059
Presynaptic nerve terminals must maintain stable neurotransmission via synaptic vesicle membrane recycling despite encountering wide fluctuations in the number and frequency of incoming action potentials (APs). However, the molecular mechanism linking variation in neuronal activity to vesicle trafficking is unknown. Here, we combined genetic knockdown and direct physiological measurements of synaptic transmission from paired neurons to show that three isoforms of dynamin, an essential endocytic protein, work individually to match vesicle reuse pathways, having distinct rate and time constants with physiological AP frequencies. Dynamin 3 resupplied the readily releasable pool with slow kinetics independently of the AP frequency but acted quickly, within 20 ms of the incoming AP. Under high-frequency firing, dynamin 1 regulated recycling to the readily releasable pool with fast kinetics in a slower time window of greater than 50 ms. Dynamin 2 displayed a hybrid response between the other isoforms. Collectively, our findings show how dynamin isoforms select appropriate vesicle reuse pathways associated with specific neuronal firing patterns. 相似文献
28.
Shuji Yonezawa Hidekuni Yamakawa Chie Muto Motoko Hosono Takahiko Yamamoto Kazunari Hattori Masahiro Sakagami Hiroko Togame Yoshikazu Tanaka Toru Nakano Hiroshi Takemoto Mitsuhiro Arisawa Satoshi Shuto 《Bioorganic & medicinal chemistry letters》2013,23(10):2912-2915
To improve the efficacy of the conformationally restricted BACE1 inhibitors, structural modifications were investigated using two strategies: (a) modification of the terminal aromatic ring and (b) insertion of a spacer between the aromatic rings. In the latter approach, another type of inhibitor 17 bearing an ethylene spacer between two aromatic rings was found to exhibit good BACE1 inhibitory activity, while the corresponding conformationally unrestricted compound 25 showed no activity. This result revealed an interesting effect of a conformational restriction with a cyclopropane ring. 相似文献
29.
Teruyoshi Matoba Hozumi Yoshida Daizo Yonezawa 《Bioscience, biotechnology, and biochemistry》2013,77(4):979-986
Casein and egg albumin were allowed to react with methyl linoleate (ML) at a relative humidity (RH) of 0% or 80% at 50°C for 10 days (protein: ML= 1:0.2 or 1:1, w/w). Changes in the molecular sizes of the reacting proteins were examined by gel filtration and gel electrophoresis. Both proteins showed similar changes, whereas the reaction at RH 80% (protein: ML= 1:1) resulted in insolubilization because of polymerization. Changes in the amino acid residues of the reacting proteins were investigated after acid (6 n HC1) and enzymatic (pepsin-pancreatin, followed by aminopeptidase-prolidase) hydrolyses. Insignificant changes were observed in the amino acid composition of proteins reacted at RH 0%. After reaction at RH 80% (protein: ML =1:1), Lys, His and Met were the only amino acids affected. The percentage loss of these amino acids after acid hydrolysis was Lys (22%), His (41%), Met (9%) for casein and Lys (22%), His (31%), Met (1%) for egg albumin. This percentage loss after enzymatic hydrolysis was Lys (41%), His (49%), Met (94%) for casein and Lys (37%), His (42%), Met (88%) for egg albumin. Some differences between our results and other researchers were also discussed. 相似文献
30.
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