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   227篇
  免费   15篇
  2023年   2篇
  2022年   9篇
  2021年   13篇
  2020年   10篇
  2019年   21篇
  2018年   16篇
  2017年   11篇
  2016年   13篇
  2015年   11篇
  2014年   9篇
  2013年   21篇
  2012年   8篇
  2011年   19篇
  2010年   8篇
  2009年   12篇
  2008年   12篇
  2007年   13篇
  2006年   6篇
  2005年   4篇
  2004年   3篇
  2003年   4篇
  2002年   7篇
  2001年   1篇
  1995年   1篇
  1990年   3篇
  1989年   1篇
  1986年   2篇
  1971年   1篇
  1970年   1篇
排序方式: 共有242条查询结果,搜索用时 265 毫秒
151.
Cold denaturation is an intriguing phenomenon in protein denaturation for elucidating protein accessible surface area (ASA). Compared to the impact of protein surface, the importance of protein-water interactions in cold denaturation may be ruled out significantly. Here, based on the ASA, we have defined a new factor, the surface stability factor (SSF). From the SSF, in combination with the cold denaturation temperature (T(g')) or temperature at DeltaS = 0 (T(s)) of a given protein, one can predict the percent of hydrophobic surface area (H), percent of total surface there on positive and negative charge sum (effective charge) be zero (C), percent of patches hydrophobicity (HP) and others critical surface parameters without any need to the crystallographic data.  相似文献   
152.
Journal of Physiology and Biochemistry - Tachykinins (TKs) include an evolutionarily conserved group of small bio-active peptides which possess a common carboxyl-terminal sequence,...  相似文献   
153.
154.
This study was performed to investigate the potential health risk of heavy metals (HMs) through consumption of market food crops (MFCs) in the Sialkot and Gujranwala districts, Pakistan. Both study areas are located in industrialized regions of the country, where atmospheric pollution is a problem and irrigation of food crops is mostly practiced on the use of wastewater/contaminated water. For the purpose of this study, MFCs samples were collected and assessed for HMs (Cr, Ni, Cd, Pb, Mn, Cu, Zn, and Fe) by using flame atomic absorption spectrophotometry. Concentration of HMs such as Pb and Cd exceeded the Food and Agriculture/World Health Organization's recommended limits in all MFCs, while Cr in most of the vegetables of the Sialkot and Gujranwala districts also exceeded that limit. The health risk index was >1 in Triticum aestivum for Pb and Cd intake in the Sialkot district and only Pb in the Gujranwala district. Therefore, this study suggests pretreatment of wastewater and its utilization for lawns and green belts irrigation, rather than for food crops. This study also suggests a regular monitoring of HMs in the irrigation water, subsequent soil, air, and MFCs in order to prevent or reduce health hazards.  相似文献   
155.
156.
This study aimed to design and evaluate enhanced permeation and retention (EPR)‐mediated anticancer effect of polymer‐modified and drug‐loaded magnetite nanocomposites. The preformulated bare (10 nm), chitosan‐superparamagnetic iron oxide (SPIO; 69 nm), heparin‐SPIO (42 nm), and (3‐aminopropyl)triethoxysilane‐polyethylene glycol‐SPIO (17 nm) nanocomposites were utilized to evaluate the EPR‐mediated localized cancer targeting and retention of doxorubicin (DOX) and paclitaxel (PTX) in human ovarian cancer cell lines, A2780 and OVCAR‐3 in vitro and in the tumor‐baring Balb/c mice in vivo. Fluorescence microscopy showed that DOX‐ and PTX‐loaded SPIO nanoparticles caused long‐term accumulation and cytoplasmic retention in A2780 and OVCAR‐3 cells, as compared to free drugs in vitro. In vivo antiproliferative effect of present formulations on immunodeficient female Balb/c mice showed a tremendous amount of ovarian tumor shrinkage within 6 weeks. The present nanocomposite systems of targeted drug delivery proved to be efficient drug carrier with sustained drug release and long‐term retention with enhanced cytotoxic properties in vitro and in vivo.  相似文献   
157.
Journal of Plant Growth Regulation - The reported study investigated the interaction between salicylic acid (SA) and citric acid (CA) in cadmium (Cd)-stressed Brassica juncea plants. Seedling...  相似文献   
158.
159.
Chemical investigation of chloroform–ethyl acetate extract from the roots of Paeonia emodi yielded four hitherto unknown noroleanane triterpenoids (14) together with four known compounds (58). Their structures were established by analysis of spectroscopic data. Compounds 18 were evaluated for cytotoxic activities against human cancer cell lines A549, HL-60, HCT116 and ZR-75-30. Compounds 1, 2, 3, 6 and 7 showed modest cytotoxicity against HL-60, HCT116 and ZR-75-30.  相似文献   
160.
A complete protocol for the saffron cormlet production under in vitro conditions and subsequent flowering under greenhouse conditions is described. Highest number of cormlets (70.0 ± 0.30) per corm slice (explant) could be regenerated on Murashige and Skoog (MS) half strength medium supplemented with thidiazuron (TDZ) (20 μM), Indole acetic acid (IAA) (10 μM), and sucrose (40 g/l). Maximum germination (90%) of these cormlets could be achieved on MS medium containing 6-benzyl amino purine (BAP) (20 μM) and α-naphthalene acetic acid (NAA) (15 μM). In order to increase the size of the in vitro raised cormlets, these were cultured on MS medium containing TDZ (15 μM) and IAA in the range of 1.5-30 μM. Maximum increase in cormlet size could be attained on TDZ (15 μM) + IAA (12.5 μM) + sucrose (30 g/l), and the average size of cormlets was 2.5g. In another experiment, apical vegetative buds of actively growing corms were cultured for cormlet development, and corms of size 2.5g could be developed on MS medium with NAA (15 μM), BAP (20 μM), and sucrose (30 g/l). The in vitro developed cormlets were dried under shade at 25 ± 2°C for 7 d. These were then planted in small cups containing clay loam soil and kept in green house at 20 ± 2°C. In vitro developed cormlets with mean weight 2.5 g showed maximum flowering (25%) as well as vegetative growth (55%), while only 19% cormlets of 2.0 g flowered. To our knowledge this is the first report on successful flowering from in vitro raised cormlets under greenhouse.  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