全文获取类型
收费全文 | 2299篇 |
免费 | 207篇 |
出版年
2022年 | 28篇 |
2021年 | 30篇 |
2020年 | 17篇 |
2019年 | 21篇 |
2018年 | 40篇 |
2017年 | 20篇 |
2016年 | 38篇 |
2015年 | 55篇 |
2014年 | 68篇 |
2013年 | 102篇 |
2012年 | 105篇 |
2011年 | 109篇 |
2010年 | 77篇 |
2009年 | 58篇 |
2008年 | 108篇 |
2007年 | 98篇 |
2006年 | 103篇 |
2005年 | 90篇 |
2004年 | 91篇 |
2003年 | 112篇 |
2002年 | 87篇 |
2001年 | 92篇 |
2000年 | 97篇 |
1999年 | 91篇 |
1998年 | 35篇 |
1997年 | 16篇 |
1996年 | 23篇 |
1995年 | 23篇 |
1994年 | 27篇 |
1993年 | 24篇 |
1992年 | 73篇 |
1991年 | 61篇 |
1990年 | 52篇 |
1989年 | 65篇 |
1988年 | 44篇 |
1987年 | 41篇 |
1986年 | 28篇 |
1985年 | 28篇 |
1984年 | 21篇 |
1983年 | 13篇 |
1982年 | 10篇 |
1981年 | 12篇 |
1979年 | 20篇 |
1978年 | 17篇 |
1977年 | 17篇 |
1976年 | 11篇 |
1975年 | 10篇 |
1974年 | 21篇 |
1970年 | 14篇 |
1966年 | 8篇 |
排序方式: 共有2506条查询结果,搜索用时 15 毫秒
921.
Development of an effective process for utilization of collagen from livestock and fish waste 总被引:26,自引:0,他引:26
A procedure for the extraction of protein and production of peptides by enzymic hydrolysis from bone and skin wastes containing collagen was developed. Fat and inorganic components were first removed in a pretreatment step and a high molecular weight protein extracted under acidic conditions (pH 3) using a 1 h reaction time at 60 °C. The molecular weight of extract from pig skin was greater than 100 kDa. The extract had a high water retention capacity, was beneficial for repair of rough skin, had no odor problem and was demonstrated to be safe in skin patch tests. It was thus considered acceptable for use in cosmetic materials. Pretreated fish bone and pig skin were hydrolyzed with a commercial enzyme. The hydrolysates had a high anti-radical activity (IPOX50, 0.18 and 0.45 mg ml−1) and a high potential for decreasing blood pressure (IC50, 0.16 and 0.41 mg ml−1), suggesting the hydrolysates could be a useful additive in food materials. 相似文献
922.
Age composition of masu salmon smolts in northern Japan 总被引:1,自引:0,他引:1
H. Hayano† Y. Miyakoshi M. Nagata K. Sugiwaka‡ J. R. Irvine§ 《Journal of fish biology》2003,62(1):237-241
Smolts of anadromous masu salmon Oncorhynchus masou aged 3+ years were found in a northern Japanese river. This is the first recording of 3+ year smolts in Japan. These fish appeared to originate in the cold upper river where 2+ year parr were found during autumn. 相似文献
923.
CND41, a chloroplast nucleoid protein that regulates plastid development, causes reduced gibberellin content and dwarfism in tobacco 总被引:1,自引:0,他引:1
Takeshi Nakano Noriko Nagata Takuma Kimura Masayo Sekimoto Hiroshi Kawaide Shinya Murakami Yasuko Kaneko Hisashi Matsushima Yuji Kamiya Fumihiko Sato Shigeo Yoshida 《Physiologia plantarum》2003,117(1):130-136
CND41, a DNA binding protein of chloroplast nucleoids, may function as a negative regulator of chloroplast gene expression. The reduction of CND41 in an antisense transformant accelerated plastid development in shoot apex cells and early young leaves, and caused a dwarf phenotype and altered leaf morphology. Plant height and leaf shape could be restored almost to those of the wild type by application of gibberellins (GAs), clearly indicating that a reduction in GA content was a prime cause of the dwarf phenotype in CND41 antisense transformants. The transformants had reduced endogenous levels of active gibberellin (GA1 ), a biologically active GA, compared to those of wild-type plants. Possible relationships between chloroplast development affected by CND41 function and GA biosynthesis are discussed. 相似文献
924.
H. Nagata H. Mutoh K. Kumahara Y. Arimoto T. Tomemori D. Sakurai K. Arase K. Ohno T. Yamakoshi K. Nakano T. Okawa T. Numata A. Konno 《Human genetics》2001,109(3):262-266
The gene for the beta-chain of the high-affinity receptor for IgE (Fc epsilon RI beta) has been proposed as a candidate gene for atopy. A coding variant Glu237Gly has been studied in various populations with asthma and atopy, and the results were controversial for association of the variant with atopy/asthma. Because nasal allergy is a more common atopic disease and shows less remission than asthma, we analyzed whether the Glu237Gly variant is correlated with nasal allergy. The study enrolled 233 patients with nasal allergy and 100 control subjects. Further, three subgroups were selected: patients with perennial nasal allergy (n=149), Japanese cedar pollinosis (n=189), and allergy to multiple allergens (n=45). The allele frequency of Gly237 in the controls and patients was 0.14 and 0.20, and the frequency of Gly237-positive subjects was 0.23 and 0.356, respectively. There was a significant association between Gly237-positivity and nasal allergy, perennial nasal allergy, Japanese cedar pollinosis, and allergy to multiple allergens. Among all 333 subjects we observed a significant relationship between Gly237 and elevated levels of serum total IgE (>250 IU/ml) and very high IgE (>1000 IU/ml). Among patients positive for a specific IgE, Gly237 was significantly associated with high IgE for house dust, mite, and Japanese cedar pollen. These results suggest that the Glu237Gly variant of the Fc epsilon RI beta gene is involved in the development of nasal allergy through the process for the production of both specific and nonspecific IgE antibodies. 相似文献
925.
Takayuki Nagata Kazuko Murata Ryo Murata Shu-lan Sun Yutaro Saito Shuhei Yamaga Nobuyuki Tanaka Keiichi Tamai Kunihiko Moriya Noriyuki Kasai Kazuo Sugamura Naoto Ishii 《Biochemical and biophysical research communications》2014
Hepatocyte growth factor (HGF)-regulated tyrosine kinase substrate (Hrs) is a vesicular sorting protein that functions as one of the endosomal-sorting proteins required for transport (ESCRT). Hrs, which binds to ubiquitinated proteins through its ubiquitin-interacting motif (UIM), contributes to the lysosomal transport and degradation of ubiquitinated membrane proteins. However, little is known about the relationship between B-cell functions and ESCRT proteins in vivo. Here we examined the immunological roles of Hrs in B-cell development and functions using B-cell-specific Hrs-deficient (Hrsflox/flox;mb1cre/+:Hrs-cKO) mice, which were generated using a cre-LoxP recombination system. Hrs deficiency in B-cells significantly reduced T-cell-dependent antibody production in vivo and impaired the proliferation of B-cells treated in vitro with an anti-IgM monoclonal antibody but not with LPS. Although early development of B-cells in the bone marrow was normal in Hrs-cKO mice, there was a significant decrease in the number of the peripheral transitional B-cells and marginal zone B-cells in the spleen of Hrs-cKO mice. These results indicate that Hrs plays important roles during peripheral development and physiological functions of B lymphocytes. 相似文献
926.
927.
Ubiquity of Bacillus thuringiensis on phylloplanes of arboreous and herbaceous plants in Japan 总被引:6,自引:1,他引:5
E. Mizuki T. Ichimatsu S. -H. Hwang Y. S. Park H. Saitoh K. Higuchi M. Ohba 《Journal of applied microbiology》1999,86(6):979-984
A total of 120 Bacillus thuringiensis strains was isolated from phylloplanes of 35 species of arboreous and herbaceous plants in an area of northern Kyushu, Japan. The isolates belonged to at least 17 serotypes and the group of H serotype 3 was predominant. Twenty strains were untypable by the existing reference H antisera and 47 were untestable due to autoagglutination or poor motility. Of the 120 isolates, 25 produced bipyramidal parasporal inclusions and the others, spherical or irregular-shaped. Insecticidal activity against mosquitoes ( Culex pipiens molestus and Anopheles stephensi ) and/or diamondback moth, Plutella xylostella , was associated with 28 isolates (23·3%). Overall results revealed that: B. thuringiensis is ubiquitous on a variety of plants; bacterial flora on phylloplanes consists of highly heterogeneous H serogroups; and there is little correlation between plant species and phenotypes of B. thuringiensis isolates. 相似文献
928.
929.
930.
The sulfate uptake and accumulation in mouse digestive organs were studied by light microscopic radioautography. Two litters of normal ddY mice 30 days after birth, each consisting of 3 animals, were studied. One litter of animals were sacrificed 30 min after the intraperitoneal injections with phosphate buffered Na2(35)SO4, and the other litter animals were sacrificed 12 hr after the injections. Then several digestive organs, the parotid gland, the submandibular gland, the sublingual gland, antrum and fundus of the stomach, the duodenum, the jejunum, the ileum, the caecum, the ascending colon and the descending colon were taken out. The tissues were fixed, dehydrated, embedded in epoxy resin, sectioned, picked up onto glass slides, coated with radioautographic emulsion by a dipping method. AFter the exposure, they were developed, stained with toluidine blue and analyzed by light microscopy. As the results, many silver grains were observed on serous cells of the salivary glands, mucosa and submucosa of the stomach, villous cells and crypt cells of the small intestines and whole mucosa of the large intestines at 30 min after the injection. Then at 12 hr after the injection silver grains were observed on mucous cells of the salivary glands, some of the stomach glands, and mucigen granules of goblet cells in the small intestines and the large intestines. The numbers of silver grains observed in respective organs at 30 min were less than those at 12 hr. From these results, it is concluded that glycoprotein synthesis was demonstrated in several digestive organs by radiosulfate incorporation. In the salivary glands the silver grains were more observed in serous cells at 30 min, while in mucous cells more at 12 hr than 30 min after the injection. In other organs the silver grains were more at 30 min than at 12 hr. These results show the time difference of glycoprotein synthesis in respective organs. 相似文献