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   20954篇
  免费   1537篇
  国内免费   11篇
  2023年   54篇
  2022年   50篇
  2021年   331篇
  2020年   247篇
  2019年   310篇
  2018年   531篇
  2017年   394篇
  2016年   680篇
  2015年   1128篇
  2014年   1224篇
  2013年   1394篇
  2012年   1826篇
  2011年   1706篇
  2010年   1099篇
  2009年   913篇
  2008年   1344篇
  2007年   1184篇
  2006年   1052篇
  2005年   971篇
  2004年   958篇
  2003年   777篇
  2002年   783篇
  2001年   625篇
  2000年   629篇
  1999年   418篇
  1998年   155篇
  1997年   121篇
  1996年   113篇
  1995年   87篇
  1994年   82篇
  1993年   69篇
  1992年   157篇
  1991年   125篇
  1990年   88篇
  1989年   103篇
  1988年   70篇
  1987年   65篇
  1986年   69篇
  1985年   53篇
  1984年   47篇
  1983年   37篇
  1982年   27篇
  1981年   24篇
  1978年   28篇
  1977年   23篇
  1976年   32篇
  1975年   29篇
  1973年   33篇
  1971年   23篇
  1969年   24篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
92.
The employees at the Pohang industrial area, where Clonorchis sinensis has been known to be endemic along the Hyungsan River, were examined parasitologically for clonorchiasis and a part of the infected cases were surveyed with a questionnaire to outline the recent infection status of C. sinensis and epidemiological parameters in the area. Total of 3,180 cases were tested by intradermal inoculation of C. sinensis antigen (Green Cross Co., Korea), and 834 (26.2%) were found positive. Out of the positive cases, 598 were subjected to fecal examination for helminth ova. The examination revealed 129 (21.6%) ova positive cases of C. sinensis, and Trichuris trichiura 1.7%, Ascaris lumbricoides 0.3%, and Metagonimus yokogawai 0.2%. The questionnaire analysis showed some significant differences between the infected and non-infected (control) groups. The infected cases were less educated than the control, and they lived at the closer area to the river, and most of them lived there over 20 years. Also they preferred eating raw fresh water fish. Most of the detected cases were treated with praziquantel and found negative for the eggs in 85.3% of them 1 year after the treatment. The present data reveal markedly decreased endemicity of clonorchiasis compared with previous prevalence rates but still clonorchiasis is endemic in the Hyungsan river basin. A comprehensive measure including case detection, treatment and education for parasite control should be applied to control clonorchiasis in such endemic areas.  相似文献   
93.
A Gram-negative, non-motile and rod-shaped bacterial strain, designated RA2-3T, was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea, and its taxonomic position was investigated by using a polyphasic approach. Strain RA2-3T was observed to grow optimally at 25 °C, at pH 7.0–7.5 and in the presence of 2 % (w/v) NaCl. Strain RA2-3T exhibited the highest 16S rRNA gene sequence similarity values to the type strains of Litoreibacter meonggei (95.7 %), Planktotalea frisia (95.6 %), Thalassobius gelatinovorus (95.5 %) and Pelagicola litoralis (95.4 %). A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain RA2-3T clustered with the type strains of Planktotalea frisia, Pelagicola litoralis, Pacificibacter maritimus and Roseovarius marinus. Strain RA2-3T was found to contain Q-10 as the predominant ubiquinone and C18:1 ω7c as the major fatty acid. The major polar lipids detected in strain RA2-3T were phosphatidylcholine, phosphatidylglycerol, one unidentified aminolipid and one unidentified lipid. The DNA G+C content of strain RA2-3T was 52.9 mol%. On the basis of the phylogenetic, chemotaxonomic and phenotypic properties, strain RA2-3T is considered to represent a new genus and species within the family Rhodobacteraceae, for which the name Halocynthiibacter namhaensis gen. nov., sp. nov. is proposed. The type strain of H. namhaensis is RA2-3T (=KCTC 32362T=NBRC 109999T).  相似文献   
94.
Artifacts following gold staining of Western-blotted membranes   总被引:1,自引:0,他引:1  
Protein samples were separated by sodium dodecyl-sulfate-polyacrylamide gel electrophoresis, electrophoretically transferred to nitrocellulose membranes, and stained with colloidal gold. Three artifact bands appeared demonstrating apparent molecular weights of 58,000, 63,000, and 65,000. The appearance of these bands was due to oxidized dithiothreitol used to denature the proteins prior to electrophoresis. The appearance of the artifact bands could be avoided by the addition of excess iodoacetamide to the denatured protein sample and by limiting staining time to 1.5 h at 13 V/cm.  相似文献   
95.
Applied Microbiology and Biotechnology - Despite the relatively low transfection efficiency and low specific foreign protein productivity (qp) of Chinese hamster ovary (CHO) cell-based transient...  相似文献   
96.
97.
98.
In a medium containing 40 g ethanol l–1, laccase production by Trametes versicolor was 2.6 unit per ml of the supernatant, which was over 20 times higher than that without ethanol. Laccase activity with ethanol was quite comparable to that with the well-known inducers such as veratryl alcohol, xylidine and guaiacol. With other white-rot fungi, Coriolus hirsutus and Grifola frondosa, ethanol had a similar stimulatory effect on laccase production.  相似文献   
99.
100.
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