全文获取类型
收费全文 | 2370篇 |
免费 | 178篇 |
出版年
2021年 | 29篇 |
2020年 | 10篇 |
2019年 | 16篇 |
2018年 | 25篇 |
2017年 | 35篇 |
2016年 | 40篇 |
2015年 | 52篇 |
2014年 | 86篇 |
2013年 | 147篇 |
2012年 | 121篇 |
2011年 | 118篇 |
2010年 | 71篇 |
2009年 | 59篇 |
2008年 | 104篇 |
2007年 | 109篇 |
2006年 | 114篇 |
2005年 | 136篇 |
2004年 | 130篇 |
2003年 | 114篇 |
2002年 | 135篇 |
2001年 | 82篇 |
2000年 | 91篇 |
1999年 | 70篇 |
1998年 | 31篇 |
1997年 | 35篇 |
1996年 | 41篇 |
1995年 | 36篇 |
1994年 | 28篇 |
1993年 | 27篇 |
1992年 | 51篇 |
1991年 | 46篇 |
1990年 | 39篇 |
1989年 | 42篇 |
1988年 | 23篇 |
1987年 | 20篇 |
1986年 | 19篇 |
1985年 | 18篇 |
1984年 | 21篇 |
1983年 | 20篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 11篇 |
1979年 | 15篇 |
1978年 | 13篇 |
1976年 | 13篇 |
1975年 | 9篇 |
1974年 | 10篇 |
1972年 | 7篇 |
1970年 | 6篇 |
1969年 | 8篇 |
排序方式: 共有2548条查询结果,搜索用时 31 毫秒
101.
Keiko Morotomi-Yano Hidenori Akiyama Ken-ichi Yano 《Biochemical and biophysical research communications》2013
Nanosecond pulsed electric fields (nsPEFs) have recently gained attention as effective cancer therapy owing to their potency for cell death induction. Previous studies have shown that apoptosis is a predominant mode of nsPEF-induced cell death in several cell lines, such as Jurkat cells. In this study, we analyzed molecular mechanisms for cell death induced by nsPEFs. When nsPEFs were applied to Jurkat cells, apoptosis was readily induced. Next, we used HeLa S3 cells and analyzed apoptotic events. Contrary to our expectation, nsPEF-exposed HeLa S3 cells exhibited no molecular signs of apoptosis execution. Instead, nsPEFs induced the formation of poly(ADP-ribose) (PAR), a hallmark of necrosis. PAR formation occurred concurrently with a decrease in cell viability, supporting implications of nsPEF-induced PAR formation for cell death. Necrotic PAR formation is known to be catalyzed by poly(ADP-ribose) polymerase-1 (PARP-1), and PARP-1 in apoptotic cells is inactivated by caspase-mediated proteolysis. Consistently, we observed intact and cleaved forms of PARP-1 in nsPEF-exposed and UV-irradiated cells, respectively. Taken together, nsPEFs induce two distinct modes of cell death in a cell type-specific manner, and HeLa S3 cells show PAR-associated non-apoptotic cell death in response to nsPEFs. 相似文献
102.
Akira Muto Masamichi Ohkura Gembu Abe Junichi Nakai Koichi Kawakami 《Current biology : CB》2013,23(4):307-311
Download : Download video (74MB) 相似文献
103.
Keiji Saito Akira Nakao Tsuyoshi Shinozuka Kousei Shimada Satoshi Matsui Kiyoshi Oizumi Kazuki Yano Keiko Ohata Daisuke Nakai Yoko Nagai Satoru Naito 《Bioorganic & medicinal chemistry》2013,21(7):1628-1642
A cell-based assay was performed for the discovery of novel bone anabolic agents. Alkaline phosphatase (ALPase) activity of ST2 cells was utilized as an indicator of osteoblastic differentiation, and thienopyridine derivative 1 was identified as a hit compound. 3-Aminothieno[2,3-b]pyridine-2-carboxamide was confirmed to be a necessary core structure for the enhancement of ALPase activity, and then optimization of the C4-substituent on the thienopyridine ring was carried out. Introduction of cyclic amino groups to the C4-position of the thienopyridine ring improved the activity. Especially, N-phenyl-homopiperazine derivatives were found to be strong enhancers of ALPase among this new series. Furthermore, 3-amino-4-(4-phenyl-1,4-diazepan-1-yl)thieno[2,3-b]pyridine-2-carboxamide (15k) was orally administered to ovariectomized (OVX) rats over 6 weeks for evaluating the effects on areal bone mineral density (aBMD), and statistically significant improvements in aBMD were observed from the dosage of 10 mg/kg/day. 相似文献
104.
105.
106.
Toshimasa Yano Tôru Kodama Kôichi Yamada 《Bioscience, biotechnology, and biochemistry》2013,77(7):580-584
The oxygen uptake rate of aggregated mycelia is decreased to an extent which, in the case of a typical spherical aggregate, could be estimated depending on its diameter, mycelial density, oxygen diffusivity, and so forth. Equations were presented in this paper to evaluate the oxygen uptake rate of an mold pellet. A favorable agreement was found between the calculation and the experiment. 相似文献
107.
Miyagawa Eiji Junko Yano Toshinari Hamakado Yasuji Kido Keiji Nishimoto Yoshinobu Motoki 《Bioscience, biotechnology, and biochemistry》2013,77(10):2881-2886
N-Benzoylgiycine amidohydrolase (hippurate hydrolase EC 3.5.1.32), which catalyzes the hydrolysis of hippuric acid to benzoic acid and glycine, was found in a cell-free extract of Pseudomonas putida C692-3 grown on a medium containing hippuric acid. The enzyme was purified from the extract by ammonium sulfate fractionation and column chromatographies on DEAE-cellulose, DEAE-Sephadex A-50, hydroxyapatite, and Sepharose CL-6B. The enzyme was finally crystallized. The crystalline enzyme was almost homogeneous on electrophoresis. The enzyme had a molecular weight of about 170,000 and consisted of four subunits identical in molecular weight (approximately 42,000). The enzyme hydrolyzed N-benzoylglycine most rapidly, and N-benzoyl-l-alanine and N-benzoyl-l-aminobutyric acid. The Km value for these substrates were 0.72 mm, 0.87 mm, and 0.87mm, respectively. The optimum pH of the enzyme reaction was 7.0 to 8.0 and the enzyme was stable from pH 6.0 to 8.0. 相似文献
108.
The process of dehydration of soybean protein coagulate in expression involves two mechanisms, filtration and consolidation. The filtration process was explained by Ruth’s filtration model. The consolidation process, except for secondary consolidation, was analyzed by the modified consolidation model of Shirato et al., taking into account the compressibility of cake. The modified coefficient of consolidation was not affected significantly by the pressure applied. Evaluation of the modified coefficient of consolidation is of importance for an attempt to improve the current production of soybean protein. 相似文献
109.
Toshiro Samejima Yoshihiko Soh Toshimasa Yano 《Bioscience, biotechnology, and biochemistry》2013,77(12):2285-2290
The equilibrium moisture contents of sun-cured (Kroumougrad), flue-cured (Bright Yellow—4) and air-cured (Burley-21 and Matsukawa) tobaccos were measured over a relative humidity range from 5 to 80% at 20°C. The moisture sorption isotherms of tobaccos were of sigmoid type, and classified into two groups. In a lower humidity range below ca. 40% RH, the A group (Kroumougrad and BY-4) had a smaller moisture sorption capacity than B group (Burley-21 and Matsukawa), while in a higher humidity range above ca. 50% RH the former had a larger moisture sorption capacity than the latter. By extracting with water, the moisture content of BY-4 was increased in the lower humidity range, while it decreased in the higher humidity range. However, the moisture content of Matsukawa was scarecely changed by extracting it with water. These results suggest that the differences in equilibrium moisture content with the type of curing were due to the differences in contents of water soluble com- ponents. To control the hygroscopic properties of a tobacco, therefore, the influences of the addition of sucrose and glycerol on the equilibrium moisture content were quantitatively analysed. The moisture sorption capacity of tobacco was greatly different from its nitrogen sorption capacity. The specific surface area of tobacco calculated from moisture sorption isotherm was ca. 110 times larger than the specific surface area calculated from the nitrogen sorption isotherm. Both the nitrogen and moisture sorption data should be necessary for better understanding of the complicated sorption-desorption phenomena in tobaccos. 相似文献
110.
Tadashi Inoue Masamichi Takagi Yasukiyo Umemura Hikoyuki Yamaguchi 《Bioscience, biotechnology, and biochemistry》2013,77(12):2457-2464
The minor RNA components in large ribosomal subunits of rat liver were analyzed by gel electrophoresis. Quantitative analysis showed that these minor components, whose apparent molecular weights ranged from 8.48 × 105 to 11.4 × 105, represented 10 to 13% of the total high-molecular-weight ribosomal RNA.It was elucidated that they were not artifacts arose during the cell homogenization, sub-cellular fractionation, RNA preparation and gel electrophoresis.Labeling experiment in vivo showed that they were preferentially present in “old” ribosomes. It was predicted that these minor components were the intermediates in the degradation of 28S ribosomal RNA in vivo.In the regenerating liver, where the degradation of proteins was reported to be blocked, the relative amount of the minor RNA components was decreased to about a half of that of normal liver. There was, however, no increase in their relative amount in the long-term starved rat liver, where RNA degradation should be going very rapidly. 相似文献