全文获取类型
收费全文 | 143篇 |
免费 | 10篇 |
专业分类
153篇 |
出版年
2021年 | 2篇 |
2018年 | 2篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 7篇 |
2012年 | 9篇 |
2011年 | 5篇 |
2010年 | 4篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 7篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1971年 | 3篇 |
1970年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1962年 | 1篇 |
1961年 | 2篇 |
1959年 | 1篇 |
1958年 | 2篇 |
1941年 | 1篇 |
1936年 | 2篇 |
1933年 | 1篇 |
1931年 | 1篇 |
排序方式: 共有153条查询结果,搜索用时 15 毫秒
1.
A L Vladimirtseva A P Ettinger E Ia Gatkin Iu V Golubenko 《Biulleten' eksperimental'no? biologii i meditsiny》1989,107(5):566-568
The authors studied morphological changes under the effect of laser radiation. Various disorders in the blood circulation have been revealed such as hyperemia, stasis which did not depend upon the exposition time. 相似文献
2.
The effects of plasma components on the kinetics of copper transport by rat hepatocytes were examined in an attempt to determine how copper is mobilized from plasma for uptake by the liver. Specific protein-facilitated transport was indicated by saturation kinetics, competition by related substrates, and similar kinetic parameters for uptake and efflux. For copper uptake, Km = 11 +/- 0.6 microM and Vmax = 2.7 +/- 0.6 nmol Cu/(min X mg protein). Zinc is a competitive inhibitor of copper uptake, and copper competes for zinc uptake. Copper efflux from preloaded cells is biphasic. The kinetic parameters for the initial rapid phase are similar to the parameters for uptake. Copper transport by hepatocytes is strictly passive. A variety of metabolic inhibitors have no effect on uptake and initial rates are solely dependent on extracellular-intracellular concentration gradients. Albumin markedly inhibits copper uptake by a substrate removal mechanism, and histidine facilitates albumin-inhibited copper uptake. The active species that delivers copper to hepatocytes under conditions of excess albumin and excess histidine is the His2Cu complex. Experiments with [3H]His2 64Cu showed that the transported species is free ionic copper. The kinetic parameters of copper transport by hepatocytes isolated from the brindled mouse model of Menkes' disease are normal. However, these cells show a decreased capacity to accumulate copper on prolonged incubation. An intracellular metabolic defect seems to be involved. 相似文献
3.
A Iu Tsibulevski? A P Ettinger 《Izvestiia Akademii nauk SSSR. Seriia biologicheskaia》1989,(6):843-849
The effect of natural (alpha-tocopherol) and synthetic (Dibunol and VN-3) antioxidants on H+ ion concentration in paramucous layer (PpH) of gut, duodenum, caecum, jejunum, and rectum in normal and vagotomized rats has been estimated 7, 14, and 30 days after introduction of the drugs. Vagotomy leads to transformation of the PpH shape of digestive tract. The effect is most pronounced at 7 days and reveals itself as an increase in PpH in gut, the decrease in PpH in duodenum and caecum. Introduction of E vitamin for 7 days led to the decrease in gut PpH and the increase in duodenum PpH in both groups of animals. Dibunol and VN-3 did not exert significant influence on the PpH of digestive tract of normal and vagotomized rats. An inhibitory effect of VN-3 on gut contractile activity in both groups of animals has been observed. 相似文献
4.
Physiologically active chloroplasts contain pools of unassembled extrinsic proteins of the photosynthetic oxygen-evolving enzyme complex in the thylakoid lumen 总被引:7,自引:0,他引:7 下载免费PDF全文
The oxygen-evolving complex (OEC) of photosystem II (PS II) consists of at least three extrinsic membrane-associated protein subunits, OE33, OE23, and OE17, with associated Mn2+, Ca2+, and Cl- ions. These subunits are bound to the lumen side of PS II core proteins embedded in the thylakoid membrane. Our experiments reveal that a significant fraction of each subunit is normally present in unassembled pools within the thylakoid lumen. This conclusion was supported by immunological detection of free subunits after freshly isolated pea thylakoids were fractionated with low levels of Triton X-100. Plastocyanin, a soluble lumen protein, was completely released from the lumen by 0.04% Triton X-100. This gentle detergent treatment also caused the release from the thylakoids of between 10 and 20%, 40 and 60%, and 15 and 50% of OE33, OE23, and OE17, respectively. Measurements of the rates of oxygen evolution from Triton-treated thylakoids, both in the presence and absence of Ca2+, and before and after incubation with hydroquinone, demonstrated that the OEC was not dissociated by the detergent treatment. Thylakoids isolated from spinach released similar amounts of extrinsic proteins after Triton treatment. These data demonstrate that physiologically active chloroplasts contain significant pools of unassembled extrinsic OEC polypeptide subunits free in the lumen of the thylakoids. 相似文献
5.
6.
A C Ettinger A A Hirata 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1976,151(3):495-497
Sera from inbred SPF White Leghorn chickens at 6 weeks or 19-22 months of age did not have anti-OA agglutinins as determined by the passive HA reaction; 2-day-old chicks also lacked the anti-OA activity. Inbred chickens kept in SPF isolators for 6 weeks, then transferred to a conventional environment for 7 weeks, produced anti-OA agglutinins. Inbred White Leghorn adult chickens conventionally reared had a high anti-OA agglutinin titer. It appeared that natural anti-OA agglutinin s are elaborated in response to environmental pathogens in certain lines of chickens. The titer in the individual chicken appeared as early as 10 weeks and was maintained until old age. The presence of natural anti-OA agglutinins did not prevent egg-laying but appears to have delayed it. The HA reaction is specific and can be absorbed. 相似文献
7.
8.
9.
Kevin R. Ford Ailene K. Ettinger Jessica D. Lundquist Mark S. Raleigh Janneke Hille Ris Lambers 《PloS one》2013,8(6)
Climate plays an important role in determining the geographic ranges of species. With rapid climate change expected in the coming decades, ecologists have predicted that species ranges will shift large distances in elevation and latitude. However, most range shift assessments are based on coarse-scale climate models that ignore fine-scale heterogeneity and could fail to capture important range shift dynamics. Moreover, if climate varies dramatically over short distances, some populations of certain species may only need to migrate tens of meters between microhabitats to track their climate as opposed to hundreds of meters upward or hundreds of kilometers poleward. To address these issues, we measured climate variables that are likely important determinants of plant species distributions and abundances (snow disappearance date and soil temperature) at coarse and fine scales at Mount Rainier National Park in Washington State, USA. Coarse-scale differences across the landscape such as large changes in elevation had expected effects on climatic variables, with later snow disappearance dates and lower temperatures at higher elevations. However, locations separated by small distances (∼20 m), but differing by vegetation structure or topographic position, often experienced differences in snow disappearance date and soil temperature as great as locations separated by large distances (>1 km). Tree canopy gaps and topographic depressions experienced later snow disappearance dates than corresponding locations under intact canopy and on ridges. Additionally, locations under vegetation and on topographic ridges experienced lower maximum and higher minimum soil temperatures. The large differences in climate we observed over small distances will likely lead to complex range shift dynamics and could buffer species from the negative effects of climate change. 相似文献
10.
We have developed a rapid and sensitive thin film assay for in-process monitoring of target protein purification. This novel biosensor method provides rapid (5-min) visual evaluation of column purification fractions. The method can be used to monitor the efficiency of purification and potential loss of protein if the column binding capacity is exceeded. The eluted fractions containing the highest yield of target protein can be quickly identified, pooled, and processed. This convenient platform, known as the SILAS product, is a thin-film detection technology in which specific molecular interactions are transduced into visible color changes based on changes in the optical thickness of layers on a silicon surface. The results are interpreted without instrumentation. Proteins eluted from a purification column are adsorbed to the assay surface, and the ligand of interest (target) can be identified with specific binding reagents. Here we demonstrate two protein purification applications for the SILAS technology product: monitoring antibody elution from a Protein G column and evaluating the efficiency of purification of a glutathione-S-transferase (GST)-tagged recombinant protein through each step of the purification process. 相似文献