全文获取类型
收费全文 | 2105篇 |
免费 | 100篇 |
国内免费 | 2篇 |
出版年
2022年 | 6篇 |
2021年 | 17篇 |
2020年 | 15篇 |
2019年 | 18篇 |
2018年 | 34篇 |
2017年 | 18篇 |
2016年 | 38篇 |
2015年 | 78篇 |
2014年 | 72篇 |
2013年 | 151篇 |
2012年 | 148篇 |
2011年 | 123篇 |
2010年 | 74篇 |
2009年 | 100篇 |
2008年 | 130篇 |
2007年 | 146篇 |
2006年 | 133篇 |
2005年 | 143篇 |
2004年 | 133篇 |
2003年 | 131篇 |
2002年 | 127篇 |
2001年 | 16篇 |
2000年 | 16篇 |
1999年 | 18篇 |
1998年 | 29篇 |
1997年 | 28篇 |
1996年 | 26篇 |
1995年 | 25篇 |
1994年 | 11篇 |
1993年 | 22篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 12篇 |
1989年 | 5篇 |
1988年 | 13篇 |
1987年 | 17篇 |
1986年 | 6篇 |
1985年 | 13篇 |
1984年 | 6篇 |
1983年 | 10篇 |
1982年 | 5篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1965年 | 3篇 |
1963年 | 2篇 |
排序方式: 共有2207条查询结果,搜索用时 15 毫秒
1.
2.
Circulating tumor cells (CTCs), shed from primary tumors and disseminated into peripheral blood, are playing a major role in metastasis. Even after isolation of CTCs from blood, the target cells are mixed with a population of other cell types. Here, we propose a new method for analyses of cell mixture at the single-cell level using a microfluidic device that contains arrayed electroactive microwells. Dielectrophoretic (DEP) force, induced by the electrodes patterned on the bottom surface of the microwells, allows efficient trapping and stable positioning of single cells for high-throughput biochemical analyses. We demonstrated that various on-chip analyses including immunostaining, viability/apoptosis assay and fluorescent in situ hybridization (FISH) at the single-cell level could be conducted just by applying specific reagents for each assay. Our simple method should greatly help discrimination and analysis of rare cancer cells among a population of blood cells. 相似文献
3.
4.
Summary An activated carbon column was utilized for the synthesis of disaccharides by use of a reversed hydrolysis activity of an immobilized -galactosidase column in order to shift the equilibrium to the direction of condensation. The yields of lactulose and allo-lactulose from galactose and fructose, and N-acetyl lactosamine and N-acetyl allolactosamine from galactose and N-acetyl glucosamine, were 11.3% and 10.0%, respectively. 相似文献
5.
Abstract Biovar A strains of Fusobacterium necrophorum exhibited high hydrophobicity when examined by the method of Rosenberg et al. Biovar B strains showed a lower cell surface hydrophobicity than biovar A strains. Biovar B strains were divided into 2 groups according to their hydrophobic activity. The strains of biovar A and the first group of biovar B were increasingly removed from aqueous phase to octane phase by increasing the volume of octane, but the turbidity of the second group of biovar B was not significantly affected. The hydrophobicity of biovar A strains decreased on heating at 60 and 100°C for 30 min. 相似文献
6.
Oka Kotaro; Ikeshima Hiroko; Ishikawa Hideo; Ohta Eiji; Sakata Makoto 《Plant & cell physiology》1988,29(5):771-775
We showed that the surface charge density of protoplasts canbe estimated by the 9-aminoacridine method. The estimated surfacecharge density of the protoplasts isolated from elongating regionsof Vigna mungo root was 39 ? 8 mC/m2. The negative surfacecharge density increased when protoplasts were treated withglutaraldehyde or when EDTA was added to the protoplast suspensionmedium. These results support the validity of our estimationof the surface charge density of protoplasts by the 9-aminoacridinemethod. The concentration of amino groups at the surface ofthe protoplasts was estimated to be 34 mC/m2. (Received June 19, 1987; Accepted April 11, 1988) 相似文献
7.
8.
H. Ohno T. Yahata K. Yamashita A. Kuroshima 《International journal of biometeorology》1988,32(1):52-55
Seven male students were studied to observe the effects of acute cold exposure (at 10°C for 60 min) on erythrocyte concentrations of glycolytic intermediates in summer and in winter. The subjects shivered slightly but frankly in both experiments. Significant decreases were observed in the concentrations of pyruvate and lactate during body cooling in summer, but not in winter. The lactate concentration remained significantly reduced 15 min after cold exposure. After 60 min of cold exposure in summer, a negative crossover point appeared to exist between phosphoenolpyruvate and pyruvate and erythrocyte pyruvate kinase activity showed a significant decrease. No seasonal difference was observed in the initial control values of the intermediates measured. From these results and the fact that glucose, pyruvate and lactate are evenly distributed between erythrocytes and plasma, it is likely that erythrocytes and skeletal muscles need less fuel substrate, glucose during cold exposure in winter than in summer, suggesting that an increased economy of energy for homeostasis is achieved. 相似文献
9.
To determine the role of the nutritional state in nonshivering thermogenesis during cold adaptation, cold adaptability was compared between cold-adapted (5 degrees C for 4-5 weeks) rats fed ad libitum and cold-adapted rats pair fed with warm controls having the same food intake. Cold-adapted pair-fed rats suffered a significant loss in body weight during cold exposure. However, brown adipose tissue (BAT) in both cold-adapted ad libitum fed and cold-adapted pair-fed rats was enlarged to the same extent as compared with that in control rats. Fat-free dry matter in BAT also increased in cold-adapted ad libitum fed and cold-adapted pair-fed rats to the same extent. Cold tolerance as assessed by the change in the colonic temperature at -5 degrees C was improved relative to control rats and was the same for cold-adapted ad libitum fed and cold-adapted pair-fed rats. Nonshivering thermogenesis as estimated by the noradrenaline-induced increase in oxygen consumption was significantly greater in the cold-exposed rats and there was no significant difference between cold-adapted ad libitum fed and cold-adapted pair-fed rats. These results suggest that an improved cold tolerance by means of nonshivering thermogenesis in brown adipose tissue is closely related to the low temperature itself but not the increased food intake which occurred in the cold. 相似文献
10.
Summary A 0.7 kb DNA fragment of the Escherichia coli K12 chromosome was shown to contain the structural gene for RNAse III (rnc). The DNA sequence of the gene was determined and its alteration in an RNAse III defective mutant, AB301-105, was identified. DNA sequence analysis also showed that a secondary-site suppressor of a temperature-sensitive mutation in the E. coli ribosomal protein gene, rpsL, occurred within the rnc gene, providing genetic evidence for the interaction of ribosomal proteins with RNAse III, which in turn acts on the nascent ribosomal RNA during assembly of ribosomes in E. coli. 相似文献