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   1824篇
  免费   86篇
  国内免费   298篇
  2023年   29篇
  2022年   36篇
  2021年   46篇
  2020年   57篇
  2019年   60篇
  2018年   45篇
  2017年   61篇
  2016年   54篇
  2015年   53篇
  2014年   75篇
  2013年   115篇
  2012年   55篇
  2011年   93篇
  2010年   64篇
  2009年   74篇
  2008年   102篇
  2007年   105篇
  2006年   84篇
  2005年   78篇
  2004年   85篇
  2003年   77篇
  2002年   65篇
  2001年   59篇
  2000年   59篇
  1999年   49篇
  1998年   55篇
  1997年   42篇
  1996年   35篇
  1995年   51篇
  1994年   45篇
  1993年   38篇
  1992年   28篇
  1991年   17篇
  1990年   24篇
  1989年   16篇
  1988年   8篇
  1987年   8篇
  1986年   11篇
  1985年   21篇
  1984年   22篇
  1983年   15篇
  1982年   10篇
  1981年   8篇
  1980年   13篇
  1979年   12篇
  1978年   10篇
  1977年   9篇
  1976年   9篇
  1974年   8篇
  1973年   4篇
排序方式: 共有2208条查询结果,搜索用时 15 毫秒
251.
紫杉醇产生菌HU1353的鉴定   总被引:9,自引:3,他引:6  
通过对紫杉醇产生菌HU1 35 3群体形态的观察 ,以及个体形态包括菌丝、分生孢子梗、分生孢子、产孢细胞、是否具喙等特征的研究 ,确定了HU1 35 3的分类地位 ,为链格孢属一新种 ,命名为红豆杉链格孢。  相似文献   
252.
253.
In the study of the biological control of plant-parasitic nematodes, knowledge of the saprophytic ability of a nematophagous fungus is necessary to understand its establishment and survival in the soil. The objectives of this study were (i) to determine if the nematophagous fungus ARF (Arkansas Fungus) shows differential use of plant residues; and (ii) to determine if ARF still existed in the soil of a field in which ARF was found originally and in which the population level of Heterodera glycines had remained very low, despite 15 years of continuous, susceptible soybean. Laboratory studies of the decomposition of wheat straw or soybean root by ARF were conducted in two separate experiments, using a CO₂ collection apparatus, where CO₂-free air was passed through sterilized cotton to remove the microorganisms in the air and then was passed over the samples, and evolved CO₂ was trapped by KOH. Milligrams of C as CO₂ was used to calculate the percentage decomposition of the plant debris by ARF. Data indicated ARF decomposed 11.7% of total organic carbon of the wheat straw and 20.1% of the soybean roots in 6 weeks. In the field soil study, 21 soil samples were taken randomly from the field. Only 3 months after the infestation of the soil with H. glycines, the percentage of parasitized eggs of H. glycines reached 64 ± 19%, and ARF was isolated from most parasitized eggs of H. glycines. Research results indicated ARF could use plant residues to survive.  相似文献   
254.
独蒜兰种子共生萌发研究   总被引:2,自引:0,他引:2  
采用从独蒜兰分离的菌根真菌与其种子在燕麦培养基上共生萌发。结果表明GN21、GN23和GN24的作用效果较好, 其中GN21萌发率84.6%, 高于对照7个百分点, 达到显著性。同时也表明, 从同一兰科植物分离到的属于同一属的不同菌根真菌种, 有的能明显促进种子萌发, 有的却不能促进萌发, 甚至产生病斑, 引起原球茎死亡。  相似文献   
255.
An endogenous filariform fungus has been separated from a tree named Taxus growing in the Aba region, Sichuan, China. The fungus is fermented in fluid medium for 3 weeks at 25℃, then the HPLC and MALDI-TOF analysis of the zymotic fluid show that the zymotic fluid contains taxol. So it is a fungus which can produce taxol. It is named Taxomyces sp. temporarily.  相似文献   
256.
杉木解酚菌的研究   总被引:6,自引:0,他引:6  
从杉木林土壤中筛选到5株高效解酚菌(F2、F3、F4、F7、F15),结果表明,F4、F33d,F2、F155d能将600rng  相似文献   
257.
258.
259.
The semi-dominantly acting Mlg resistance locus in barley confers race-specific resistance to the obligate biotrophic fungus Erysiphe graminis f.sp. hordei. A high-resolution genetic map was constructed at Mlg based on a cross between the near-isogenic barley lines Pallas BC5 Mlg and Pallas mlg. A total of 2000 F2 progeny were inspected by cleaved amplified polymorphic sequence (CAPS) analysis, defining a 4.47 cM interval encompassing the resistance locus. Pathogen challenge of the segregants with multiple powdery mildew isolates uncovered a novel resistance specificity in Pallas BC5 Mlg. Probes from within 4.0 cM of Mlg were mapped in rice, revealing orthologues on five different rice chromosomes and suggesting multiple breaks of chromosomal collinearity in this region between the two grass species. The most tightly Mlg-linked RFLP marker, MWG032, was shown to reliably detect the presence of the resistance allele in a collection of 30 European barley cultivars. Received: 23 March 2000 / Accepted: 20 April 2000  相似文献   
260.
A two-stage process for the bioremediation of blue Stilton whey has been developed. It employs both naturally occurring thermotolerant organisms found in whey (lactic acid bacteria and yeast) and a thermophilic isolate (Bacillus sp.). Thermophilic digestion occurred only at neutral pH. Multiple substrates were consumed simultaneously under mesophilic but not thermophilic conditions.  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