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   321篇
  免费   12篇
  333篇
  2024年   1篇
  2023年   2篇
  2022年   9篇
  2021年   22篇
  2020年   11篇
  2019年   8篇
  2018年   16篇
  2017年   9篇
  2016年   6篇
  2015年   20篇
  2014年   20篇
  2013年   23篇
  2012年   23篇
  2011年   22篇
  2010年   12篇
  2009年   7篇
  2008年   14篇
  2007年   15篇
  2006年   11篇
  2005年   14篇
  2004年   10篇
  2003年   8篇
  2002年   7篇
  2001年   3篇
  2000年   4篇
  1999年   7篇
  1998年   1篇
  1997年   1篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1992年   3篇
  1990年   2篇
  1989年   2篇
  1986年   2篇
  1985年   3篇
  1984年   2篇
  1980年   1篇
  1979年   2篇
  1969年   4篇
  1968年   1篇
排序方式: 共有333条查询结果,搜索用时 0 毫秒
261.
262.
Yadav  V.  Shahzad  A.  Ahmad  Z.  Sharma  S.  Parveen  S. 《Plant Cell, Tissue and Organ Culture》2019,138(2):363-376
Plant Cell, Tissue and Organ Culture (PCTOC) - Non-embryogenic, synthetic seeds were formed by encapsulating the nodal segments (NS) of Hemidesmus indicus R. Br. in calcium alginate hydrogel...  相似文献   
263.
The incidence of babesiosis, Lyme disease and other tick-borne diseases has increased steadily in Europe and North America during the last five decades. Babesia microti is transmitted by species of Ixodes, the same ticks that transmit the Lyme disease-causing spirochete, Borrelia burgdorferi. B. microti can also be transmitted through transfusion of blood products and is the most common transfusion-transmitted infection in the U.S.A. Ixodes ticks are commonly infected with both B. microti and B. burgdorferi, and are competent vectors for transmitting them together into hosts. Few studies have examined the effects of coinfections on humans and they had somewhat contradictory results. One study linked coinfection with B. microti to a greater number of symptoms of overall disease in patients, while another report indicated that B. burgdorferi infection either did not affect babesiosis symptoms or decreased its severity. Mouse models of infection that manifest pathological effects similar to those observed in human babesiosis and Lyme disease offer a unique opportunity to thoroughly investigate the effects of coinfection on the host. Lyme disease has been studied using the susceptible C3H mouse infection model, which can also be used to examine B. microti infection to understand pathological mechanisms of human diseases, both during a single infection and during coinfections. We observed that high B. microti parasitaemia leads to low haemoglobin levels in infected mice, reflecting the anaemia observed in human babesiosis. Similar to humans, B. microti coinfection appears to enhance the severity of Lyme disease-like symptoms in mice. Coinfected mice have lower peak B. microti parasitaemia compared to mice infected with B. microti alone, which may reflect attenuation of babesiosis symptoms reported in some human coinfections. These findings suggest that B. burgdorferi coinfection attenuates parasite growth while B. microti presence exacerbates Lyme disease-like symptoms in mice.  相似文献   
264.
CpG oligodeoxynucleotides (CpG-ODN) stimulate immune cells from a wide spectrum of mammalian species. Class C CpG-ODN is relatively stable and has the combined immune effects of both A and B classes of CpG-ODN. Trypanosoma evansi produces the state of immuno-suppression in the infected hosts. The current chemotherapeutic agents against this parasite are limited in number and usually associated with severe side effects. The present work aimed to determine the immunostimulatory effects of CpG-ODN class C in T. evansi infected rabbits. Rabbits inoculated with CpG C and challenged with T. evansi resulted in delayed onset of clinical signs with reduced severity in comparison to that of T. evansi infected rabbits. The treatment also enhanced humoral immune responses. Histopathological findings in liver and spleen revealed enhancement of mononuclear cell infiltration and secondary B cell follicles. These results demonstrate that CpG-ODN class C, has immunostimulatory properties in rabbit model of trypanosomosis. The use of booster doses or sustained delivery of CpG-ODN will further elucidate the prolonged CpG-ODN generated immune responses.  相似文献   
265.
Journal of Plant Biochemistry and Biotechnology - Powdery mildew is a serious fungal disease of wheat caused by Blumeria graminis f. sp. tritici. Chromosome 5U of Aegilops triuncialis carrying...  相似文献   
266.
Molecular Breeding - Rice (Oryza sativa L.) is a saline-alkali-sensitive crop. Saline-alkali environments can seriously affect the growth, development, and yield of rice. The mechanisms of salt...  相似文献   
267.
268.
Chthoniobacter flavus Ellin428 is the first isolate from the class Spartobacteria of the bacterial phylum Verrucomicrobia. C. flavus Ellin428 can metabolize many of the saccharide components of plant biomass but is incapable of growth on amino acids or organic acids other than pyruvate.  相似文献   
269.
The activities of Glutamate decarboxylase (GAD) and Gamma aminobutyric acid (GABA) were studied in three regions of rat brain in heightened neuronal activity resulting in convulsions by Leptazol. These enzymes were studied in preconvulsive, convulsive and post convulsive phases. The activity of GAD decreases significantly in the preconvulsive phase in all the three regions of brain followed by a significant increase during the convulsive and post convulsive phase in cerebral cortex and cerebellum. The activity of GABA-T decreases maximal during the preconvulsive phase followed by convulsive phase. The activity of this enzyme tended to increase to control values when the postconvulsive phase was reached. Therefore, it is suggested that the concomitant decrease of GAD activity and GABA concentration, is probably an important factor in the onset of convulsions.  相似文献   
270.
Ethyl acetate soluble fraction of methanolic extract of Launaea nudicaulis was subjected to chromatographic purification to get four new compounds including a quinic acid derivative (1), a pentahydroxy acetylene analog: trideca-12-ene-4,6-diyne-2,8,9,10,11-pentaol (2), a flavone glycoside (3) and a sesquiterpene lactone (4) together with 10 known compounds. The structures of the new isolates were established by using 1D, 2D NMR techniques and high-resolution mass spectrometry, whereas, the known isolates were identified based on 1D NMR and mass spectrometric information and in comparison with the reported data in the literature. The structure of 4 was also confirmed through single X-ray crystallographic analysis. Cholistaquinate (1) exhibited significant activity in DPPH free radical scavenging assay with an IC50 value of 60.7 μM, whereas, nudicholoid (4) exhibited a moderate inhibitory activity against the enzyme butyrylcholinesterase with an IC50 value of 88.3 μM.  相似文献   
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