全文获取类型
收费全文 | 852篇 |
免费 | 57篇 |
出版年
2023年 | 2篇 |
2021年 | 14篇 |
2020年 | 4篇 |
2019年 | 10篇 |
2018年 | 19篇 |
2017年 | 19篇 |
2016年 | 18篇 |
2015年 | 33篇 |
2014年 | 39篇 |
2013年 | 42篇 |
2012年 | 51篇 |
2011年 | 67篇 |
2010年 | 31篇 |
2009年 | 35篇 |
2008年 | 65篇 |
2007年 | 66篇 |
2006年 | 55篇 |
2005年 | 44篇 |
2004年 | 55篇 |
2003年 | 44篇 |
2002年 | 33篇 |
2001年 | 7篇 |
2000年 | 7篇 |
1999年 | 11篇 |
1998年 | 10篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 11篇 |
1991年 | 8篇 |
1990年 | 11篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1979年 | 7篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 5篇 |
1972年 | 1篇 |
排序方式: 共有909条查询结果,搜索用时 15 毫秒
1.
2.
Yoshinao Nakagawa Manabu Totsuka Tomoaki Sato Yoshiro Fukuda Koichi Hirota 《European journal of applied physiology and occupational physiology》1989,59(3):239-242
We examined the influence exerted, through disuse of the hindlimb, on the collagen fibres of the achilles tendon in rats. With disuse the body mass decreased by 28%, and the mass of soleus muscle decreased by 20%. A decrease in the surface area and diameter was observed in the experimental group when compared to the control group. A histogram of the collagen fibres showed a decrease of the thick fibres in the experimental group. The maximum surface area of collagen fibres in the experimental group was seen to be only 43% of that of the control group. These results showed a decrease in the thickness of the collagen fibres of the achilles tendon through disuse. This seemed to suggest that resistance to tension is decreased by disuse. 相似文献
3.
Chloroplast DNA (cpDNA) and mitochondrial DNA (mtDNA) of malesterile tobacco plants obtained by fusion of Nicotiana tabacumprotoplasts and X-irradiated N. debneyi protoplasts were analyzed.Digestion of cpDNA isolated from ten male sterile lines withfour restriction endonucleases (EcoRI, XhoI, SmaI and HindIII)indicated that these lines possessed either one or the otherparental chloroplast genome. Neither mixture of two types ofcpDNA nor unique restriction fragments were detected in anyof the cases examined. The genetic constitution of chloroplastgenomes identified by restriction analysis of cpDNA showed goodagreement with that based on isoelectric focusing of the largesubunit of the Fraction I protein. The mtDNA from five fusion-derivedmale sterile plants showed banding patterns quite differentfrom each other and from the parental plants. Each plant exhibitednew restriction fragments not found in the parental species.These findings indicate that recombinational events in the mitochondrialgenomes take place rather frequently in the mixed cytoplasmsafter protoplast fusion, whereas the mixed chloroplasts becomesegregated to homogeneity. (Received June 19, 1987; Accepted October 5, 1987) 相似文献
4.
A flower-inducing substance of high molecular mass, extracted from Lemna paucicostata, was purified to homogeneity. It had characteristics of a polypeptide, with an amino-terminal sequence of Leu-Val-Gly-Asn-Thr, and induced formation of flower buds of L. paucicostata 151 at a concentration of 10−10 molar. 相似文献
5.
Evidence for direct binding of Clostridium botulinum type E derivative toxin and its fragments to gangliosides and free fatty acids 总被引:4,自引:0,他引:4
Y Kamata S Kozaki G Sakaguchi M Iwamori Y Nagai 《Biochemical and biophysical research communications》1986,140(3):1015-1019
Clostridium botulinum type E derivative toxin and its heavy chain bound to gangliosides GT1b, GD1a and GQ1b and saturated and unsaturated free fatty acids with chain lengths of 14-20 carbons. The L-H-1 fragment lacking the carboxyl-terminal portion of the heavy chain bound to free fatty acids but not to gangliosides. These observations led us to a new hypothesis on the mechanism of binding between botulinum toxin and gangliosides; the carboxyl-terminal portion (H-2 fragment) of the heavy chain binds to an oligosaccharide residue of gangliosides and then the amino-terminal portion (H-1 fragment) interacts with the hydrophobic portion of gangliosides consisting of fatty acids. 相似文献
6.
Yohichi Kamata Shunji Kozaki Takafumi Nagai Genji Sakaguchi 《FEMS microbiology letters》1985,26(3):305-309
Abstract Five monoclonal antibodies (MCA; E–8–2, 9–1, 11–2, 12–4, and 13–1) against Clostridium botulinum type E derivative toxin were prepared. Their ELISA titers were higher than or equivalent to that of conventional polyclonal antibody. Three of them (E-8–2, 12–4, and 13–1) possessed the neutralizing activity comparable to that of polyclonal antibody. The results of binding-competition experiments indicated that the monoclonal antibodies bound to different sites on the type E toxin molecule. Immunoblotting analyses demonstrated that E-8–2, 9–1, and 11–2 react to fragment I (heavy chain) of the toxin. By use of these monoclonal antibodies, it may be possible to scrutinize the structure-function relationship of botulinum toxins and cross reactions between type E and F toxins. 相似文献
7.
Use of monoclonal antibodies in enzyme linked immunosorbent assay (ELISA) for detection of botulinum type B toxins 总被引:3,自引:0,他引:3
S Notermans S Kozaki Y Kamata G Sakaguchi 《Japanese journal of medical science & biology》1984,37(3):137-140
Use of polyclonal antibodies failed to correlate mouse assay with enzyme linked immunosorbent assay (ELISA) in titration of culture fluid of different strains of Clostridium botulinum type B. If ELISA is performed with such a monoclonal antibody that is capable of neutralizing the toxin, however, the lethal toxicity can be determined quantitatively. 相似文献
8.
Akira Inokuchi Yasunobu Tomida Chizuko Yanaihara Ryogo Yui Yutaka Oomura Hiroshi Kimura Takanobu Hase Tomoaki Matsumoto Noboru Yanaihara 《Cell and tissue research》1986,246(1):71-75
Summary Immunohistochemically, nerve fibers and terminals reacting with anti-N-terminal-specific but not with anti-C-terminal-specific glucagon antiserum were observed in the following rat hypothalamic regions: paraventricular nucleus, supraoptic nucleus, anterior hypothalamus, arcuate nucleus, ventromedial hypothalamic nucleus and median eminence. Few fibers and terminals were demonstrated in the lateral hypothalamic area and dorsomedial hypothalamic nucleus. Radioimmunoassay data indicated that the concentration of gut glucagon-like immunoreactivity was higher in the ventromedial nucleus than in the lateral hypothalamic area. In food-deprived conditions, this concentration increased in both these parts. This was also verified in immunostained preparations in which a marked enhancement of gut glucagon-like immunoreactivity-containing fibers and terminals was observed in many hypothalamic regions. Several immunoreactive cell bodies were found in the ventromedial and arcuate nuclei of starved rats. Both biochemical and morphological data suggest that glucagon-related peptides may act as neurotransmitters or neuromodulators in the hypothalamus and may be involved in the central regulatory mechanism related to feeding behavior and energy metabolism. 相似文献
9.
Yoshiya Shigematsu Ken Tsukahara Tomoaki Tanaka Michio Takeuchi Dr. Eiji Ichishima 《Current microbiology》1986,13(1):43-46
The molecular properties, such as molecular weight, N-and C-terminal amino acids, amino acid composition, and circular dichroism, of 1,2--mannosidase isolated from the culture filtrate ofAspergillus saitoi were determined.The enzyme had aK
m of 0.67 mM andk
cat of 1.27/s with mannobiose at pH 50.0 and 30°C. The anomeric configuration of the reaction products of the enzyme was examined by studying the -anomer. A single Manl2Man linkage in intact Taka-amylase A fromAspergillus oryzae was hydrolyzed, producing free mannose. 相似文献
10.
Shoichi Asano Toshio Matsuda Kazuhiro Takuma Hye Sun Kim Tomoaki Sato Takashige Nishikawa Akemichi Baba 《Journal of neurochemistry》1995,64(6):2437-2441
Abstract: The effects of nitric oxide (NO)-generating agents on 45 Ca2+ uptake in rat brain slices and cultured rat astrocytes were studied in the presence of monensin, which is considered to drive the Na+ -Ca2+ exchanger in the reverse mode. Sodium nitroprusside (SNP) at >10 µ M increased monensin-stimulated Ca2+ uptake in the slices, although it did not affect high K+ -stimulated Ca2+ uptake. Another NO donor, 3-morpholinosydnonimine, was effective. The effect of SNP was antagonized by hemoglobin (50 µ M ), a NO scavenger, and mimicked by 8-bromo-cyclic GMP (100 µ M ). In rat brain synaptosomes, SNP increased monensin-stimulated Ca2+ uptake, but it did not affect high K+ -stimulated Ca2+ uptake. 8-Bromocyclic GMP, but not SNP, increased Na+ -dependent Ca2+ uptake significantly in synaptic membrane vesicles in the absence of monensin. In cultured rat astrocytes, SNP and 8-bromo-cyclic GMP increased Ca2+ uptake in the presence of ouabain and monensin, which were required for the Ca2+ uptake in the cells. These findings suggest that NO stimulates the Na+ -Ca2+ exchanger in neuronal preparations and astrocytes in a cyclic GMP-dependent mechanism. 相似文献