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   479篇
  免费   27篇
  2023年   8篇
  2022年   11篇
  2021年   15篇
  2020年   16篇
  2019年   16篇
  2018年   29篇
  2017年   12篇
  2016年   21篇
  2015年   21篇
  2014年   19篇
  2013年   29篇
  2012年   32篇
  2011年   50篇
  2010年   29篇
  2009年   14篇
  2008年   22篇
  2007年   18篇
  2006年   15篇
  2005年   14篇
  2004年   14篇
  2003年   6篇
  2002年   8篇
  2001年   8篇
  2000年   4篇
  1999年   6篇
  1997年   3篇
  1996年   3篇
  1995年   8篇
  1992年   1篇
  1991年   3篇
  1990年   1篇
  1989年   3篇
  1988年   4篇
  1987年   2篇
  1986年   4篇
  1985年   1篇
  1982年   4篇
  1981年   4篇
  1980年   4篇
  1979年   4篇
  1978年   1篇
  1977年   4篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
  1973年   1篇
  1971年   1篇
  1970年   1篇
  1967年   2篇
  1965年   1篇
排序方式: 共有506条查询结果,搜索用时 46 毫秒
1.
2.
Summary The dry-matter yield and nitrogen uptake of berseem (Trifolium alexand-drinum), yield, nitrogen uptake, nodulation and leghaemoglobin content of dhaincha (Sesbania aculeata) inoculated with specific rhizobia were appreciably influenced by the application of sodium humate to soil under green house conditions. Even the application of sodium humate alone without bacterial inoculation had good growth stimulating influence on both the crops, and this effect was further improved by the application of inorganic nitrogen to dhaincha plants. A fair increase in the yield and phosphorus up-take of wheat (Triticum vulgare) inoculated withAzotobacter and/orBacillus spp. was also recorded with the addition of the humic material to the soil. The greatest effect was observed on the plants inoculated withAzotobacter andBacillus spp. together.  相似文献   
3.
4.
5.

Arsenic (As) contaminated food chains have emerged as a serious public concern for humans and animals and are known to affect the cultivation of edible crops throughout the world. Therefore, the present study was designed to investigate the individual as well as the combined effects of exogenous silicon (Si) and sodium nitroprusside (SNP), a nitric oxide (NO) donor, on plant growth, metabolites, and antioxidant defense systems of radish (Raphanus sativus L.) plants under three different concentrations of As stress, i.e., 0.3, 0.5, and 0.7 mM in a pot experiment. The results showed that As stress reduced the growth parameters of radish plants by increasing the level of oxidative stress markers, i.e., malondialdehyde and hydrogen peroxide. However, foliar application of Si (2 mM) and pretreatment with SNP (100 µM) alone as well as in combination with Si improved the plant growth parameters, i.e., root length, fresh and dry weight of plants under As stress. Furthermore, As stress also reduced protein, and metabolites contents (flavonoids, phenolic and anthocyanin). Activities of antioxidative enzymes such as catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (POD), and polyphenol oxidase (PPO), as well as the content of non-enzymatic antioxidants (glutathione and ascorbic acid) decreased under As stress. In most of the parameters in radish, As III concentration showed maximum reduction, as compared to As I and II concentrations. However, the individual and combined application of Si and NO significantly alleviated the As-mediated oxidative stress in radish plants by increasing the protein, and metabolites content. Enhancement in the activities of CAT, APX, POD and PPO enzymes were recorded. Contents of glutathione and ascorbic acid were also enhanced in response to co-application of Si and NO under As stress. Results obtained were more pronounced when Si and NO were applied in combination under As stress, as compared to their individual application. In short, the current study highlights that Si and NO synergistically regulate plant growth through lowering the As-mediated oxidative stress by upregulating the metabolites content, activity of antioxidative enzymes and non-enzymatic antioxidants in radish plants.

  相似文献   
6.
Incubation of cucumber cotyledons with fusicoccin increasedtheir fresh weights and chlorophyll levels and this effect wasenhanced by KCl. Addition of fusicoccin to this combinationincreased fresh weights but decreased chlorophyll levels. Thissuggests that the effects of fusiccocin on these two processesare probably mediated via different mechanisms. (Received January 4, 1982; Accepted March 25, 1982)  相似文献   
7.
8.
Administration of phenobarbitone caused a marked increase in the capacity of rat brain microsomes to produce thiobarbituric acid-reactive substances in vitro. Enzymatic peroxidation of lipids was more affected than the nonenzymatic processes occurring in heat-inactivated preparations. Analysis of the phospholipid profile showed a drastic decrease in phosphatidylcholine and total phospholipid contents in the exposed animals, but about a fivefold increase in the lysophosphatidylcholine fraction. Data for in vivo incorporation of [14C]choline showed a similar pattern of high radioactivity in lysolecithin. The increase in lipid peroxidation could be related to the higher level of lysolecithin and the accompanying structural and functional changes in microsomes resulting from the neurotoxic effects of phenobarbitone.  相似文献   
9.
In search of selective carbonic anhydrase (CA) IX inhibitors endowed with apoptotic inducing properties, we designed and synthesised two subsets of 4- and 3-(5-aryl-(4-phenylsulphonyl)-1H-1,2,3-triazol-1-yl)benzenesulphonamides. All compounds were assayed for human carbonic anhydrase (hCA) isoforms I, II, IV, and IX inhibition. Isoforms hCA I and hCA IV were weakly inhibited by most of the synthesised compounds. Many four-substituted benzenesulphonamides displayed low nanomolar inhibition against isoform hCA II, unlike the three-substituted analogues. All target compounds exhibited good inhibition profile with KI values ranging from 16.4 to 66.0 nM against tumour-associated isoform hCA IX. Some selective and potent inhibitors of hCA IX were assayed for in vitro apoptotic induction in goat testicular cells. Compounds 10d and 10h showed interesting apoptotic induction potential. The present study may provide insights into a strategy for the design of novel anticancer agents based on hCA inhibitors endowed with apoptotic interference.  相似文献   
10.
Comparative studies were performed to evaluate composting potential, biomass growth and biology of a non-native (Eisenia fetida) and an endemic (Lampito mauritii) species of earthworm in the semiarid environment of Jodhpur district of Rajasthan in India. Earthworms were reared in a mixed bedding material comprised of biogas slurry, cowdung, wheat straw, leaflitter, sawdust and kitchen waste. The percentage of organic carbon of the culture bedding material declined upto 105 days with E. fetida and 120 with L. mauritii. The percentage of nitrogen, phosphorous and potassium increased as a function of the vermicomposting period. In contrast, C/N and C/P ratios decreased day by day. Both species were effective for decomposition and mineralization of mixed bedding in the semiarid environment. A comparative assessment of biomass growth of E. fetida and L. mauritii was done under controlled laboratory conditions. The optimum temperature, moisture content and pH for E. fetida were 25 degrees C, 70% and 6.5, respectively. However, the optimum temperature, moisture content and pH for growth and development of L. mauritii were 30 degrees C, 60% and 7.5, respectively. The biology and reproductive rates of both species were also studied in the laboratory using mixed bedding. Cocoon production was higher for E. fetida than L. mauritii. The net reproductive rate was 9 per month in the case of E. fetida and 1 per month for L. mauritii. Fertilized eggs of E. fetida and L. mauritii developed into adults within 4 and 5 1/4 months, respectively. These observations indicate E. fetida may be a more efficient breeder than L. mauritii in the desert region of Rajasthan.  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