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   47995篇
  免费   3429篇
  国内免费   19篇
  2023年   145篇
  2022年   461篇
  2021年   931篇
  2020年   578篇
  2019年   697篇
  2018年   1057篇
  2017年   918篇
  2016年   1516篇
  2015年   2359篇
  2014年   2698篇
  2013年   3036篇
  2012年   3995篇
  2011年   3837篇
  2010年   2432篇
  2009年   2220篇
  2008年   3073篇
  2007年   2955篇
  2006年   2579篇
  2005年   2404篇
  2004年   2192篇
  2003年   1893篇
  2002年   1644篇
  2001年   1326篇
  2000年   1238篇
  1999年   1000篇
  1998年   402篇
  1997年   342篇
  1996年   249篇
  1995年   216篇
  1994年   208篇
  1993年   175篇
  1992年   329篇
  1991年   297篇
  1990年   267篇
  1989年   228篇
  1988年   175篇
  1987年   165篇
  1986年   132篇
  1985年   105篇
  1984年   82篇
  1983年   85篇
  1982年   63篇
  1981年   53篇
  1980年   55篇
  1979年   70篇
  1978年   51篇
  1977年   51篇
  1976年   44篇
  1975年   45篇
  1974年   65篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
International Journal of Primatology - Agonistic intergroup interactions can cause individual costs such as physical injuries, increased physiological stress, and disrupted intragroup social...  相似文献   
992.
Biological Trace Element Research - Obesity is a risk factor for metabolic syndrome, dyslipidemia, hypertension, insulin resistance, type 2 diabetes mellitus, and cardiovascular disease. However,...  相似文献   
993.
Biological Trace Element Research - In this study, the pattern of metals concentration in water, sediment, plants, and three edible fish species (Channa striata, Labeo rohita, and Catla catla) of...  相似文献   
994.
995.
Hong  Sung Hyun  Singh  Sudhir  Tripathi  Bhumi Nath  Mondal  Suvendu  Lee  Sangmin  Jung  Hyun Suk  Cho  Chuloh  Kaur  Shubhpreet  Kim  Jin-Hong  Lee  Sungbeom  Bai  Hyoung-Woo  Bae  Hyeun-Jong  Lee  Sang Yeol  Lee  Seung Sik  Chung  Byung Yeoup 《Protoplasma》2020,257(3):807-817
Protoplasma - Alkyl hydroperoxide reductase subunit F (AhpF) is a well-known flavoprotein that transfers electrons from pyridine nucleotides to the peroxidase protein AhpC via redox-active...  相似文献   
996.
Coral Reefs - Sharks play important functional roles in coral reef ecosystems. Studying reef shark populations’ spatial ecology also contributes important data for effective conservation...  相似文献   
997.
This study examined the control of nosemosis caused by Nosema ceranae, one of the hard-to-control diseases of honey bees, using RNA interference (RNAi) technology. Double-stranded RNA (dsRNA) for RNAi application targeted the mitosome-related genes of N. ceranae. Among the various mitosome-related genes, NCER_100882, NCER_101456, NCER_100157, and NCER_100686 exhibited relatively low homologies with the orthologs of Apis mellifera. Four gene-specific dsRNAs were prepared against the target genes and applied to the infected A. mellifera to analyze Nosema proliferation and honey bee survival. Two dsRNAs specifics to NCER_101456 and NCER_100157 showed high inhibitory effects on spore production by exhibiting only 62% and 67%, respectively, compared with the control. In addition, these dsRNA treatments significantly rescued the honey bees from the fatal nosemosis. It was confirmed that the inhibition of Nosema spore proliferation and the increase in the survival rate of honey bees were resulted from a decrease in the expression level of each target gene by dsRNA treatment. However, dsRNA mixture treatment was no more effective than single treatments in the rescue from the nosemosis. It is expected that the four newly identified mitosome-related target genes in this study can be effectively used for nosemosis control using RNAi technology.  相似文献   
998.
Mi-Ah Kim  Jae-Hwan Kim 《Biofouling》2020,36(3):256-265
Abstract

This study aimed to evaluate the effects of tea extracts on oral biofilm colonization depending on steeping temperature. S. mutans and S. sobrinus were cultured and treated with green or black tea extracts prepared under different steeping conditions. Biofilm formation, glucosyltransferase (GTF) levels, bacterial growth, and acidogenicity were evaluated. Biofilms were also assessed by gas chromatography-mass spectrometry and confocal laser scanning microscopy. All extracts with hot steeping showed higher inhibitory effects on biofilm formation and cell viability and lower GTF levels compared with those with cold steeping (p?<?0.05). Hot steeping significantly reduced bacterial growth (p?<?0.05) and maintained the pH. Catechins were only identified from hot steeping extracts. Within the limits of this study, extracts with cold steeping showed lower inhibitory effects on oral biofilms. The different effects between steeping extracts may be attributed to the difference in catechins released from tea extracts under the different steep conditions.  相似文献   
999.
1000.
A large amount of research within organic biosensors is dominated by organic electrochemical transistors (OECTs) that use conducting polymers such as poly(3,4-ethylene dioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS). Despite the recent advances in OECT-based biosensors, the sensing is solely reliant on the amperometric detection of the bioanalytes. This is typically accompanied by large undesirable parasitic electrical signals from the electroactive components in the electrolyte. Herein, we present the use of in situ resonance Raman spectroscopy to probe subtle molecular structural changes of PEDOT:PSS associated with its doping level. We demonstrate how such doping level changes of PEDOT:PSS can be used, for the first time, on operational OECTs for sensitive and selective metabolite sensing while simultaneously performing amperometric detection of the analyte. We test the sensitivity by molecularly sensing a lowest glucose concentration of 0.02 mM in phosphate-buffered saline solution. By changing the electrolyte to cell culture media, the selectivity of in situ resonance Raman spectroscopy is emphasized as it remains unaffected by other electroactive components in the electrolyte. The application of this molecular structural probe highlights the importance of developing biosensing probes that benefit from high sensitivity of the material's structural and electrical properties while being complimentary with the electronic methods of detection.  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