全文获取类型
收费全文 | 1261篇 |
免费 | 66篇 |
出版年
2022年 | 6篇 |
2021年 | 16篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 15篇 |
2016年 | 23篇 |
2015年 | 37篇 |
2014年 | 37篇 |
2013年 | 84篇 |
2012年 | 59篇 |
2011年 | 72篇 |
2010年 | 48篇 |
2009年 | 60篇 |
2008年 | 83篇 |
2007年 | 95篇 |
2006年 | 85篇 |
2005年 | 92篇 |
2004年 | 95篇 |
2003年 | 96篇 |
2002年 | 81篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 12篇 |
1997年 | 12篇 |
1996年 | 6篇 |
1995年 | 11篇 |
1994年 | 19篇 |
1993年 | 15篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 3篇 |
1981年 | 9篇 |
1980年 | 7篇 |
1979年 | 3篇 |
1978年 | 8篇 |
1975年 | 7篇 |
1974年 | 3篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1970年 | 4篇 |
1969年 | 3篇 |
排序方式: 共有1327条查询结果,搜索用时 15 毫秒
1.
Corynebacterium equi IFO 3730 was found to oxidize a wide variety of sec-alcohols, including alkanols, substituted alkanols, alkenols and cyclic alcohols, in moderate to high yields. Among them, the sec-alcohols which have longer carbon chains were oxidized more smoothly than those with smaller numbers of carbon. Although both enantiomers of unsymmetrically disubstituted carbinols were oxidized, the S form of 2-dodecanol was converted to the corresponding ketone a little faster than the other enantiomer. 相似文献
2.
The development of the bovine ileal mucosa was studied with particular reference to maturation during the fetal and neonatal period. In this region, by 4-5 months of fetal development, vacuolation of the epithelial cells had occurred on the villi, and the goblet and absorptive cells in the crypts were present. By 6-9 months, the villi were longer and more numerous than in the previous stages. At the same time, the vacuolated cells could be seen predominantly on the upper half of each villus. The absorptive cells and goblet cells were more distinct in the crypt and lower half of each villus. Moreover, the goblet cells showed differences in mucin, while in the submucosa the lymphoid follicles were seen to have enlarged to become a prominent feature of the Peyer's patches at this stage. At birth, in suckled animals, the ileal cells on the lower area of each villus and in the crypt appeared more like mature cells. In contrast, there were numerous inclusion bodies in epithelial cells on the upper half of each villus. They appeared in the apical portion of the cytoplasm as vacuoles with stainable or dense contents. By 1 week, however, epithelial cells no longer contained inclusion bodies, and absorptive and goblet cell populations had begun to emerge from the crypts. These histological results suggest that the bovine ileal mucosa has two distinct turning points during its development in the fetus and the neonate. Initially all the mucosal structures are present in fetuses at 6-7 months of gestation, and then the vacuolated cells covering the ileal villi are replaced by mature, nonpinocytosing epithelium which emerges from the crypts on or before the 7th day after birth (ileal closure). 相似文献
3.
Conformational change of bovine serum albumin by heat treatment 总被引:1,自引:0,他引:1
Kunio Takeda Akira Wada Kazuo Yamamoto Yoshiko Moriyama Koichiro Aoki 《Journal of Protein Chemistry》1989,8(5):653-659
The thermal denaturation of bovine serum albumin (BSA) was studied at pH 2.8 and 7.0 in the range of 2–65°C. The relative proportions of -helix, -structure, and disordered structure in the protein conformation were determined as a function of temperature, by the curve-fitting method of circular dichroism spectra. With the rise of temperature at pH 7.0, the proportion of -helix decreased above 30°C and those of -structure and disordered structure increased in the same temperature range. The structural change was reversible in the temperature range below 45°C. However, the structural change was partially reversible upon cooling to room temperature subsequent to heating at 65°C. On the other hand, the structural change of BSA at pH 2.3 was completely reversible in the temperature range of 2–65°C, probably because the interactions between domains and between subdomains might disappear due to the acid expansion. The secondary structure of disulfide bridges-cleaved BSA remained unchanged during the heat treatment up to 65°C at pH 2.8 and 7.0. 相似文献
4.
Toshiho Nishita Hidetoshi Oshige Hiroharu Matsushita Yutaka Kano Masao Asari 《The Histochemical journal》1989,21(1):8-14
Summary Carbonic anhydrase III has been localized using the avidin-biotin-glucose oxidase complex (ABC) method in the submandibular gland of the rat and hamster. This isozyme, which is predominant in skeletal muscle, was observed in intercalated duct, striated duct and excretory duct cells in the rat submandibular glands. In contrast, only some striated duct cells in hamster submandibular glands were stained. 相似文献
5.
Kunio Yonemasu Takako Sasaki Yoshiko Dohi Charles M. Lapière Betty Nusgens 《生物化学与生物物理学报:疾病的分子基础》1990,1096(1):47-51
C1q, a collagen-like complement protein, was purified from the serum of a ddermatosparactic calf which lacks procollagen N-terminal proteinase (pN-proteinase). The specific hemolytic activity of the serum Clq from the dermatosparactic animal was identical to that of C1q from a normal calf. Gel-filtration of serum from dermatosparactic calf, on Sepharose 6B, showed the presence of C1q-antigenic material at only one position which was identical to the elution position of normal bovine C1q. No differdence, under dissociating conditions, could be seen in the size of the chains of C1q in specific immunoprecipitates isolated from the sera of dermatosparactic and normal animals, as judged by polyacrylamidegel electrophoresis (PAGE) in the presence of sodium dodecyl sulfate (SDS). The C1q from the dermatosparactic animal showed the same N-terminal amino acid and typtic-digest peptide pattern on HPLC as C1q from the normal calf. These results strongly suggest that pN-proteinase is not involved in the extracellular processing of C1q. 相似文献
6.
Yoshiko Kubota Akihiro Shima 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1991,160(6):621-625
Summary By using inbred strains (HO4C and HB32C) of the medaka,Oryzias latipes, the involvement of genetic factor(s) in the determination of thermoresistance of fish was investigated. The thermoresistance of embryos of the medaka was quantitated by the fraction of the embryos surviving 1 day after heat treatment. At early stages of development (st. 13 and st. 20–21), the HO4C strain was more resistant than the HB32C strain. At st. 20–21, the HO4C strain was more resistant than the HB32C strain at all temperatures used (42, 43, and 44°C). At later stages of development (st. 27 and st. 32), however, the HB32C strain was more resistant than the HO4C strain.The results of genetic cross experiments raised the following possibilities; the thermoresistance of embryos at early developmental stages can be lowered by some factor(s) inherited in the HO4C strain and/or increased by those in the HB32C strain. By contrast, the sensitivity of embryos at later stages of development was not affected by factor(s) of their parents, but by their own genetic constitution. 相似文献
7.
The arrangement of wall microtubules (MTs) in Pisum sativumroots was viewed immunofluorescently using cryosectioning. Mostcells in the tip region of pea roots (02 mm from tip)had wall MTs arranged transversely to the root axis. In theregion elongating at a higher rate (24 mm), wall MTsof epidermal, cortical and stelar cells were all transverselyarranged. In the region of about 5 mm from the tip, in whichcell elongation had already ceased, wall MTs in cortical cellschanged from a transverse to an oblique arrangement in relationto the root axis. Some cells had a crossed arrangement of wallMTs, which was interpreted as representing two sets of unidirectional,oblique wall MTs in opposite cell cortices of a single cell.This change was completed within a region of 1-mm width. Sinceroots elongated at a rate of 0.6 mm h1, it means thatthe arrangement of wall MTs changed within 2 h. An oblique arrangementof wall MTs was also observed in stelar cells. As the cellsaged, the oblique arrangement tended to change to a steeperor even a longitudinal one. (Received January 24, 1986; Accepted May 15, 1986) 相似文献
8.
Tatsuo Nakayama Maki Irikura Yoshiko Setoguchi Masami Nakayama Mitsuyoshi Mochizuki Kikuo Ogata 《Molecular & general genetics : MGG》1985,201(2):252-257
Summary Non-histone chromatin proteins prepared from the livers of estrogen-treated and nontreated male chickens were compared by reverse-phase high performance liquid chromatography (RP-HPLC), followed by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The results revealed that the hormone-treated male liver chromatin contained a specific protein corresponding to the vitellogenin-specific protein previously purified from the liver of egg-laying hens (Nakayama 1985). The chicken protein, purified further by gel-filtration high performance liquid chromatography (GF-HPLC), showed specific binding activity to DNA fragments carrying a part of the vitellogenin gene. On the basis of similarities in the elution patterns from GF-HPLC and RP-HPLC as well as in the mobility on SDS-PAGE, we concluded that this hormone-induced protein in the male chicken liver was identical to the vitellogenin-specific protein identified in the hen liver, and assumed it to be a specific regulatory protein for the vitellogenin gene expression. The amino acid composition of this chicken protein has been determined. 相似文献
9.
Tanaka Kiyoshi; Suda Yoshiko; Kondo Noriaki; Sugahara Kiyoshi 《Plant & cell physiology》1985,26(7):1425-1431
The relationship between O3 tolerance and the chloroplast H2O2scavenging system (PS I 相似文献
10.
Shoei Furukawa Isao Kamo Yoshiko Furukawa Saeko Akazawa Eijiro Satoyoshi Koji Itoh Kyozo Hayashi 《Journal of neurochemistry》1983,40(3):734-744
Abstract: A sensitive two-site enzyme immunoassay system for mouse β nerve growth factor (NGF) was developed, based on the sandwiching of the antigen between anti-mouse β NGF antibody IgG coated to a polystyrene tube and anti-mouse β NGF antibody Fab'-linked β- d -galactosidase (β- d -galactoside hydrolase, EC 3.2.1.23). This method has the following advantages: (a) the procedures are simple and rapid compared to bioassay or two-site radioimmunoassay; (b) antibody Fab'-β- d -galactosidase complex is more stable than 125 I-labeled antibody; (c) purified β NGF is detectable at a concentration as low as 10 pg/ml. Our enzyme immunoassay was used to examine the levels of NGF in some tissues of mice. The submaxillary gland contained a high concentration of NGF. However, other tissues, such as the heart, brain, and skeletal muscle, and serum did not contain detectable NGF. These results support recent findings by other investigators that NGF was not found in the organs/tissues other than the submaxillary gland of mice. 相似文献