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   8802篇
  免费   739篇
  国内免费   680篇
  2024年   4篇
  2023年   107篇
  2022年   141篇
  2021年   414篇
  2020年   307篇
  2019年   435篇
  2018年   390篇
  2017年   251篇
  2016年   415篇
  2015年   583篇
  2014年   693篇
  2013年   775篇
  2012年   885篇
  2011年   757篇
  2010年   437篇
  2009年   432篇
  2008年   454篇
  2007年   396篇
  2006年   357篇
  2005年   258篇
  2004年   250篇
  2003年   200篇
  2002年   148篇
  2001年   132篇
  2000年   120篇
  1999年   102篇
  1998年   98篇
  1997年   89篇
  1996年   79篇
  1995年   68篇
  1994年   60篇
  1993年   41篇
  1992年   72篇
  1991年   44篇
  1990年   28篇
  1989年   32篇
  1988年   22篇
  1987年   23篇
  1986年   20篇
  1985年   20篇
  1984年   9篇
  1983年   6篇
  1982年   7篇
  1979年   9篇
  1978年   5篇
  1976年   4篇
  1973年   5篇
  1971年   5篇
  1970年   3篇
  1968年   6篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
High-molecular-weight glutenin subunits (HMW-GS) in wheat grain are the major determinants of dough elasticity and viscosity and thus of bread-making quality. PCR-based molecular markers designed based on DNA polymorphisms were used to analyze HMW-GS genes in wheat. The loop-mediated isothermal amplification (LAMP) assay is a simple and rapid method for specific detection of genomic DNA target sequences. In the present study, we designed a set of LAMP markers by targeting the unique sequences of 1Dx2 and 1Dx5 genes. The primers could effectively distinguish the 1Dx2 and 1Dx5 genes from other genes at the Glu-1 locus. The results were confirmed by agarose gel electrophoresis. For visualization, ethidium bromide was used, and fluorescence only appeared in the positive samples. Under optimal conditions, the detection could be finished in 1 h. Thirty-eight wheat cultivars with known HMW-GS were used to validate LAMP markers for 1Dx2 and 1Dx5 genes. Only DNA samples with target genes could be amplified, and the results could be read easily using this method. The tests using LAMP were easy to perform, rapid, and sensitive. Thus, the current study results have the potential to be a powerful tool for the detection of HMW-GS genes in wheat.  相似文献   
4.
This study investigated the effect of sunlight-dark conditions on volatile fatty acids (VFAs), total ammonium nitrogen (TAN), total alkalinity (TA) and pH during pig manure (PM) digestion and then the subsequent influence on biogas yield of PM. PM1 and PM2 were performed in a transparent reactor and a non-transparent reactor, respectively. Two sets of experiments were conducted with a temperature of 35.0±2.0 °C and a total solid concentration of 8.0% to the digestion material. The dynamic change of the four parameters in response to sunlight-dark conditions resulted in variations of the physiological properties in the digester and affected the cumulative biogas production (CBP). PM1 obtained higher CBP (15020.0 mL) with a more stable pH and a lower TAN concentration (1414.5 mg/L) compared to PM2 (2675.0 mL and 1670.0 mg/L, respectively). The direct path coefficients and indirect path coefficients between the four parameters and CBP were also analyzed.  相似文献   
5.
6.
7.
8.
9.
Du  Jingjing  Qv  Mingxiang  Li  Ke  Yin  Xiaoyun  Meng  Fanxiao  Yang  Jingchao  Ma  Chuang 《Limnology》2019,20(2):173-179
Limnology - The impacts of three commonly used benzophenone-type UV filters including benzophenone (BP), 2-hydroxy-4-methoxy-benzophenone (BP3), and 2-hydroxy-4-methoxy-benzophenone-5-sulfonicacid...  相似文献   
10.
Studies were conducted to determine the relationship between the pretherapy characteristics of leukemia cells and their behaviour during culture in vitro. Leukemia cells which proliferated well in vitro also proliferated well in vivo. Cells which manifested myeloid or monocytic differentiation in vivo tended to manifest differentiation along these lines in vitro. Cells which manifested high levels of expression of c-fms, c-fes, or triose phosphate isomerase prior to culture were likely to differentiate in vitro, with high levels of c-fes expression being related to myeloid maturation. These observations suggest that differentiation at the molecular level prior to culture is a requisite for leukemia cell differentiation in vitro. The same may be true for differentiation in vivo under the influence of exogenously administered agents such as cytotoxic chemotherapy or recombinant growth factors.  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