首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   33篇
  免费   0篇
  33篇
  2017年   1篇
  2015年   1篇
  2014年   1篇
  2013年   1篇
  2010年   1篇
  2009年   1篇
  2004年   2篇
  2003年   1篇
  2002年   3篇
  1999年   2篇
  1998年   2篇
  1997年   3篇
  1995年   1篇
  1991年   1篇
  1983年   1篇
  1981年   2篇
  1979年   2篇
  1976年   2篇
  1975年   1篇
  1970年   2篇
  1964年   2篇
排序方式: 共有33条查询结果,搜索用时 0 毫秒
1.
The levels of free and conjugated oestrone, oestradiol-17β and oestradiol-17α were estimated in bovine colostrum of the 1st, 2nd and 3rd drawing. The values obtained of free oestrone and oestradiol-17β were generally below the lowest value significantly (P = 0.01) different from zero (4.5–5.0 µg per 1) in the method applied. The values of conjugated oestrone and oestradiol-17β in the first drawing exceeded the lowest value significantly different from zero (1.5–2.0 µg per 1) by factors of 2–4 and averaged 6.1 and 3.7 µg per 1 respectively in the five cows examined. The levels of conjugated oestrone and oestradiol-17β in the 2nd and the 3rd drawing were apparently lower than in the 1st drawing. As compared with the values obtained of free and conjugated oestrone and oestradiol-17β, the corresponding values of oestradiol-17α were generally much smaller, in none of the samples exceeding 1 µg per 1. In some samples oestradiol-17α could not be detected. The results are discussed in relation to previous bioassays of colostrum oestrogens.  相似文献   
2.
The diaminobenzoic acid dihydrochloride fluorescence method has been examined to determine optimal conditions for the assay of DNA in perchloric acid extracts and in pretreated Chlamydomonas cells on glass-fiber filters. Maximal fluorescence yield was obtained by allowing: (a) the perchloric acid extract to react with 4–6% diaminobenzoic acid dihydrochloride for 20–40 min at 60–80°C at about pH 3.0; (b) the pretreated cells on glass-fiber filters to react with a 20% solution of diaminobenzoic acid dihydrochloride for 40 min at 60°C.  相似文献   
3.
Serum alkaline phosphatase activity was determined in 290 Norwegian goats, from 8 months to 10 years of age. The investigations revealed a wide range of individual enzyme activities which constituted two distinct peaks with mean values of 2.37 ± 1.42 and 37.73 ± 14.78 “Sigma” units per ml respectively. Forty-one of the 290 goats were examined by 15 successive samplings for 18 months without obtaining lapping-over values between the two groups. The segregation of the high enzyme level indicated a genetic dominant inheritance.  相似文献   
4.
    
  相似文献   
5.
Two ovariectomized cows were injected intramuscularly once daily with 300 i.u. of ACTH*) on three consecutive days. The urine was collected with the aid of rubber mats. The method for oestrogen analysis comprised acid hydrolysis of the urine, saponification of the phenolic fraction, inethylation and column chromatography followed by fluorimetry (Lunaas 1964 and unpublished).  相似文献   
6.
Whereas Arctic benthic decapods are not a species-rich group, they can dominate the local epifauna and play important roles in the ecosystem. We studied the decapod fauna from Isfjorden (Svalbard, Norway, 78°N) by sampling from 22 stations and comparing with 50 and 100-year-old data from the same localities. Our data provide no evidence of changes in the species composition of decapods during the last 50 years. Hence, we do not observe the poleward shift of species found in several pelagic communities in the North Atlantic. However, there is statistical evidence for changes in the community structure between 1908 and both 1958 and 2007. The main change is a shift towards communities more dominated by the spider crab Hyas araneus and the hermit crab Pagurus pubescens in 2007, and with a corresponding decrease in the two shrimp species Lebbeus polaris and Spirontocaris spinus. These shrimps are specialist predators compared to the more opportunistic, scavenging crabs. We argue that increased disturbance levels may be a causal factor behind the observed community change, with likely sources of disturbance including trawling and climatic fluctuations.  相似文献   
7.
Synchronization and synchronous growth of a cell wall-less mutant of Chlamydomonas reinhardii have been described. The following growth conditions were used: A modified Sueokas' high salt minimal medium, 1410 h light-dark cycle, growth temperature 30°C, light intensity 12–18 Klux and dilution of the culture at the end of the dark to a constant cell density of 1.0·106 cells/ml. The time course of increase and distribution of cell volume, cytoplasmic and nuclear division, release of motile cells after the division period and accumulation of DNA, RNA and protein are reported. These mutant cells did not make any sporangium in which the dividing cells were kept as a unit inside a mother cell wall. However, they usually adhered during the period of division, thus making clumps containing 2, 4 and 8 cells. Several of these cell clumps dissolved releasing either single or couples of 2 and 4 cells. After the end of division the cells became flagellated and motile and thereby releasing themselves from the aggregate.Non-Standard Abbreviations AWV average weighed cell volume - MM minimal medium - HSM high salt medium - TCA trichloroacetic acid  相似文献   
8.
Twenty-four flocks comprising 2370 breeding goats were examined. Threehundred-and-sixty-nine (15.6 %) of the goats either aborted or delivered dead kids at full term, or were barren. In 23 of the herds the rate of reproductive loss ranged from 2 % to 36 %, whereas in one herd all of 54 mated goats had live kids. A loss of ≥ 20 % was found in 9 herds comprising 799 goats. In 11 herds comprising 946 goats the rate of reproductive failure was ≤ 10 %. The incidence of reproductive failure was higher in older goats than in those in their first or second pregnancy. The causes were identified in only about 3 % of the goats that aborted. It is concluded that reproductive failure in many flocks probably is associated with non-infectious causes such as nutritional and environmental factors.  相似文献   
9.
Chlamydomonas reinhardtii Dang, was grown in a chemostat culture under phosphate limitation. The steady state concentration of phosphate was below the detection limit (< 1 μg P/L) in all runs. The cellular content of phosphorus (Qp), polyphosphate (Qpp) and chlorophyll a increased with increasing dilution rate, and the growth rate of the alga was described by Qp as well as Qpp in the Droop model. The ratio Qpp/Qp and the activity of alkaline phosphatase were maximal at high and low growth rates, respectively. Palmelloids of Chlamydomonas were found at high dilution rates (D > 0.12 h?1) and became attached to the wall of the culture vessel. They differed from the vegetative stage in both chemical composition and growth rate. Their contents of phosphorus and chlorophyll a were low, as in the vegetative cells, which grew at a low growth rate, whereas the ration Qpp/Qp and the activity of alkaline phosphatase were comparable with those of fast growing vegetative cells. The growth rate of the palmelloids was 0.03 h?1 whereas maximum growth rate (μm) for the vegetative cells was 0.21 h?1.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号