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   1152篇
  免费   63篇
  国内免费   5篇
  1220篇
  2024年   5篇
  2023年   19篇
  2022年   45篇
  2021年   77篇
  2020年   32篇
  2019年   60篇
  2018年   61篇
  2017年   35篇
  2016年   51篇
  2015年   67篇
  2014年   62篇
  2013年   73篇
  2012年   75篇
  2011年   78篇
  2010年   41篇
  2009年   33篇
  2008年   37篇
  2007年   49篇
  2006年   43篇
  2005年   32篇
  2004年   27篇
  2003年   24篇
  2002年   18篇
  2001年   18篇
  2000年   15篇
  1999年   7篇
  1998年   7篇
  1996年   7篇
  1995年   10篇
  1994年   9篇
  1993年   7篇
  1992年   4篇
  1991年   8篇
  1990年   7篇
  1989年   6篇
  1988年   15篇
  1987年   7篇
  1986年   3篇
  1985年   9篇
  1984年   4篇
  1983年   3篇
  1982年   2篇
  1981年   3篇
  1977年   2篇
  1976年   3篇
  1974年   2篇
  1973年   3篇
  1972年   3篇
  1971年   3篇
  1966年   2篇
排序方式: 共有1220条查询结果,搜索用时 15 毫秒
101.
Habib  K. A.  Islam  Md. J.  Nahar  N.  Neogi  A. K.  Fraser  T. H. 《Journal of Ichthyology》2021,61(4):505-513
Journal of Ichthyology - Three species of cardinalfishes viz. Ostorhinchus cookii (Macleay, 1881), Lepidamia kalosoma (Bleeker, 1852) and Apogonichthyoides sialis (Jordan et Thompson, 1914)...  相似文献   
102.
In this study, the phytochemical, phenolic, flavonoid and bioactive compounds were successfully screened from crude extract of Sargassum wightii by LC-MS analysis after NIST interpretation. Bacterial growth inhibition study result was shown with 24 mm zone inhibition at 200 µg/mL concentration against P. aeruginosa. The increased phenolic content was much closed to gallic acid and the range was observed at 250 μg/mL concentration. In addition, flavonoid contents of the algae extract was indicated more significant with rutin at 200 μg/mL. In result, both the phenolic and flavonoid contents of the extract were more correlated with gallic acid and rutin. Further, the total anti-oxidant and DPPH radical scavenging activities were shown increased activity at 200 μg/mL concentrations. Furthermore, the excellent anti-bacterial alteration result was observed at 200 μg/mL concentration by minimum inhibition concentration. Therefore, the result was revealed that the marine algae Sargassum wightii has excellent phytochemical and anti-oxidant activities, and it has improved anti-bacterial activity against P. aeruginosa.  相似文献   
103.
In continuation of our previous study on the urease inhibition by a number of chalcones, 2,3-dihydro-1,5-benzothiazepines and 2,3,4,5-tetrahydro-1,5-benzothiazepines, FlexX docking has been exploited to get a deeper insight into the mechanism of their inhibitory action. A comparison of the IC50 values of the active compounds reveals that, of the three classes of compounds studied, 2,3-dihydro-1,5-benzothiazepines were the most potent urease inhibitors. An in silico examination of these compounds showed that the activity is related to the interaction of ligand with the nickel metallocentre, its interaction with two amino acid residues, Asp224 and Cys322, in addition to the orientation of rings A and B in the catalytic core of the enzyme. The most active compound 2,3-dihydro-1,5-benzothiazepine (4) anchor tightly through a network of interactions with Ni701 and Ni702. This includes a number of hydrogen bonds and hydrophobic contacts with the amino acid residues in its vicinity. For their reduced analogs, the difference in the activity of different diastereomers has been observed to be configuration-dependent. This may be ascribed mainly to the difference in the orientation of ring B of the two stereoisomers and the extent of their interaction with Asp224 and Cys322 present in the catalytic core of the enzyme.  相似文献   
104.
Journal of Plant Growth Regulation - Despite the plethora of published reports on ameliorative effects of exogenously applied salicylic acid (SA) to plants under salt stress, a critical role of SA...  相似文献   
105.
106.
Like the majority of Columbiformes, the Laughing Dove Spilopelia senegalensis is sexually monomorphic in plumage, but seems to be slightly dimorphic in size. However, due to the lack of studies little is known about the sexual size dimorphism in this species. In this work, we used morphometric data on a sample of 61 Laughing Doves from southern Tunisia, and sexed using a DNA-based method, to assess size differences between males and females and to determine a discriminant function useful for sex identification. The results showed that wing length was the most dimorphic trait, which could be due to the effects of sexual selection. The best function for the discrimination between sexes included wing length and head length, which is comparable with findings on other dove species. This discriminant function accurately classified 89% of birds, providing a rapid and accurate tool for sex identification in the studied population. Further data from different populations are needed for firmer conclusions about the extent of sexual size dimorphism and the reliability of the morphometric sexing approach in this dove species.  相似文献   
107.
Ali  Wajid  Iqbal  Shahid  Ullah  Muhib  Wang  Xiaoli 《Plasmonics (Norwell, Mass.)》2022,17(2):709-715
Plasmonics - In this paper, we demonstrate a plasmonic ultrahigh narrowband perfect absorber, which realizes an absorption intensity of up to 99.99% in the near-infrared electromagnetic spectrum...  相似文献   
108.
109.
110.
Development and reproductive traits of Tetranychus macfarlanei Baker & Pritchard (Acari: Tetranychidae) were investigated on kidney bean, Phaseolus vulgaris L., at eleven constant temperatures. Tetranychus macfarlanei was able to develop and complete its life cycle at temperatures ranging from 17.5 to 37.5°C. At 15 and 40°C, a few eggs (2–4%) hatched but further development was arrested. Development from egg to adult was slowest at 17.5°C and fastest at 35°C for both females and males. Using Ikemoto and Takai’s linear model, the estimated lower developmental thresholds for egg-to-female adult, egg-to-male adult and egg-to-egg development were 12.9–13.0°C. The thermal constants for the respective stages were 110.85, 115.99 and 125.32 degree-days (DD). The intrinsic optimum temperatures (T Φ) calculated by non-linear SSI model were determined as 24.4, 24.4 and 24.2°C for egg-to-female adult, egg-to-male adult and egg-to-egg development, respectively. The net reproductive rate (R 0) was highest at 25°C (167.4 females per female) and lowest at 17.5°C (42.6 females per female). The intrinsic rate of natural increase, r m, increased linearly with the rising of temperature from 0.102 at 17.5°C to 0.441 day−1 at 35°C. These values suggested that T. macfarlanei could be growing quickly in response to increasing temperatures from 17.5 to 35°C and provide a basis for predicting its potential geographical range.  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