全文获取类型
收费全文 | 67篇 |
免费 | 0篇 |
出版年
2014年 | 1篇 |
2013年 | 1篇 |
2012年 | 1篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1994年 | 1篇 |
1992年 | 3篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 3篇 |
1969年 | 2篇 |
1968年 | 3篇 |
1966年 | 2篇 |
1965年 | 3篇 |
排序方式: 共有67条查询结果,搜索用时 31 毫秒
1.
A model for determination of the admixture concentration in the secondary mother solution was developed. The concentration was determined depending on the solvent volume used for repulping the precipitate and on the impurity level of the initial antibiotic paste. When the values of X1 and X2 are known it is possible to estimate the amount of the admixtures remaining in the paste layer after separation of the secondary mother solution with regard to the volume of the latter in the precipitate pores. Optimization of paste repulping should be considered in combination with displacement washing and the apparatus used for separation of the phases, as well as the requirements for the purity level of the finished product. 相似文献
2.
G L Piatigorskaia O Iu Zhilkova L M Murav'eva L F Sukhodub 《Molekuliarnaia biologiia》1986,20(2):423-429
DNA interaction with an alkylating antitumor drug N,N',N"-triethylenethiophosphoramide (thiotepa) in water-salt solutions at 37 degrees C has been studied by UV-spectroscopy, heat denaturation and electron microscopy methods. Changes of the DNA melting curve parameters provide information on the kinetics of alkylation. The dependence of the alkylation rate on DNA and thiotepa concentrations shows that the alkylation reaction is biomolecular. The increase of sodium chloride concentration from 10(-3) to 10(-1) M is accompanied by a drastic decrease of the alkylation rate. Thiotepa binding results in destabilization of the DNA secondary structure and formation of cross-links. An increased amount of bounded thiotepa results in DNA denaturation; prolonged alkylation causes breaks in the sugar-phosphate backbone. The results of the work are discussed in connection with the literature data on DNA interaction with thiotepa in vivo. 相似文献
3.
M N Zhadin B V Bakharev L I Murav'eva 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》1977,27(6):1173-1178
The average correlation coefficient between the EEG of different parts of the cortex gradually decreases as the rabbit is habituated to the experimental surroundings. Elaboration of an electo-defensive conditioned reflex leads to its enhancement which is replaced by a phase of temporary decrease, to be followed again by an enhancement of EEG correlation. The pronouncedness of theta-frequencies in the spectral and coherent functions behaves in a similar way. Successive changes of delta-activity level reveal no regularity. 相似文献
4.
5.
6.
Vladimirova NM Murav'eva TI Ovchinnikova TV Potapenko NA Khodova OM 《Membrane & cell biology》1998,12(3):435-439
Active preparations of Na+,K(+)-ATPase containing three types of catalytic isoforms were isolated from the bovine brain to study the structure and function of the sodium pump. Na+,K(+)-ATPase from the brain grey matter was found to have a biphasic kinetics with respect to ouabain inhibition and to consist of a set of isozymes with subunit composition of alpha 1 beta 1, alpha 2 beta m and alpha 3 beta m (where m = 1 and/or 2). The alpha 1 beta 1 form clearly dominated. For the first time, glycosylation of the beta 1-subunit of the alpha 1 beta 1-type isozymes isolated from the kidney and brain was shown to be different. Na+,K(+)-ATPase from the brain stem and axolemma consisted mainly of a mixture of alpha 2 beta 1 and alpha 3 beta 1 isozymes having identical ouabain inhibition constants. In epithelial and arterial smooth muscle cells, where the plasma membrane is divided into functionally and biochemically distinct domains, the polarized distribution of Na+,K(+)-ATPase is maintained through interactions with the membrane cytoskeleton proteins ankyrin and spectrin (Nelson and Hammerton, 1989; Lee et al., 1996). We were the first to show the presence of the cytoskeleton protein tubulin (beta 5-isoform) and glyceraldehyde-3-phosphate dehydrogenase in a high-molecular-weight complex with Na+,K(+)-ATPase in brain stem neuron cells containing alpha 2 beta 1 and alpha 3 beta 1 isozymes. Consequently, the influence of not only subunit composition, but also of glycan and cytoskeleton structures and other plasma membrane-associated proteins on the functional properties of Na+,K(+)-ATPase isozymes is evident. 相似文献
7.
Samaiya A Deo SS Thulkar S Hazarika S Kumar S Parida DK Shukla NK 《World journal of surgical oncology》2005,3(1):3-7
BACKGROUND: Malignant small bowel tumors are very rare and leiomyosarcoma accounts for less than 15% of the cases. Management of these tumors is challenging in view of nonspecific symptoms, unusual presentation and high incidence of metastasis. In this case report, an unusual presentation of jejunal sarcoma and management of liver metastasis with radiofrequency ablation (RFA) is discussed. CASE PRESENTATION: A 45-year-old male presented with anemia and features of small bowel obstruction. Operative findings revealed a mass lesion in jejunum with intussusception of proximal loop. Resection of bowel mass was performed. Histopathological findings were suggestive of leiomyosarcoma. After 3-years of follow-up, the patient developed recurrence in infracolic omentum and a liver metastasis. The omental mass was resected and liver lesion was managed with radiofrequency ablation. CONCLUSION: Jejunal leiomyosarcoma is a rare variety of malignant small bowel tumor and a clinical presentation with intussusception is unusual. We suggest that an aggressive management approach using a combination of surgery and a newer technique like RFA can be attempted in patients with limited metastatic spread to liver to prolong the long-term survival in a subset of patients. 相似文献
8.
JINDŘIŠKA BOJKOVÁ KLÁRA KOMPRDOVÁ TOMÁŠ SOLDÁN SVĚTLANA ZAHRÁDKOVÁ 《Freshwater Biology》2012,57(12):2550-2567
1. Rapid expansion and intensification of anthropogenic activities in the 20th century has caused profound changes in freshwater assemblages. Unfortunately, knowledge of the extent and causes of species loss (SL) is limited due to the lack of reliable historical data. An unusual data set allows us to compare changes in the most sensitive of aquatic insect orders, the Plecoptera, at some 170 locations in the Czech Republic between two time periods, 1955–1960 and 2006–2010. Historical data (1890–1911) on assemblages of six lowland rivers allow us to infer even earlier changes. 2. Regional stonefly diversity decreased in the first half of the 20th century. Streams at lower altitudes lost a substantial number of species, which were never recovered. In the second half of the century, large‐scale anthropogenic pressure caused SL in all habitats, leading to a dissimilarity of contemporary and previous assemblages. The greatest changes were found at sites affected by organic pollution and a mixture of organic pollution and channelisation or impoundment. Colonisation of new habitats was observed in only three of the 80 species evaluated. 3. Species of moderate habitat specialisation and tolerance to organic pollution were most likely to be lost. Those with narrow specialisations in protected habitats were present in both historical and contemporary collections. 4. Contemporary assemblages are the consequence of more than a 100 years of anthropogenic impacts. In particular, streams at lower altitude and draining intensively exploited landscapes host a mere fragment of the original species complement. Most stonefly species are less frequently present than before, although their assemblages remain almost intact in near‐natural mountain streams. Our analyses demonstrate dramatic restriction of species ranges and, in some cases, apparent changes in altitudinal preference throughout the area. 相似文献
9.
Murav'eva SV Deshkovich AA Shelepin IuE 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2008,94(6):637-649
In psychophysical and electrophysiological investigations, we tested the hypothesis that in patients with multiple sclerosis at its early stage either phasic cells of the magnocellular pathway or tonic cells of the parvocellular pathway are disturbed. Healthy humans and patients with early stage of diseases have a contrast spatial-frequency sensitivity measure. The decrease in sensitivity at low, medium and high spatial frequency indicates changes in parvo- and magno-system activity. The data are separated into two clusters. Psychophysical data is in good accordance with electrophysiological data of visual evoked potentials (VEPs). First group of patients showed changes of the amplitude of positive wave P100 whereas in second group of patients changes of negative wave N80 dominated comparative to healthy subjects. According to some literature data these changes were specific for M-pathway and for P-pathway. 相似文献
10.
Moderate alcohol consumption is associated with better endothelial function: a cross sectional study
Keiko Suzuki Mitchell SV Elkind Bernadette Boden-Albala Zhezhen Jin Grace Berry Marco R Di Tullio Ralph L Sacco Shunichi Homma 《BMC cardiovascular disorders》2009,9(1):1-5