全文获取类型
收费全文 | 6566篇 |
免费 | 430篇 |
国内免费 | 11篇 |
出版年
2023年 | 75篇 |
2022年 | 249篇 |
2021年 | 384篇 |
2020年 | 146篇 |
2019年 | 181篇 |
2018年 | 271篇 |
2017年 | 178篇 |
2016年 | 260篇 |
2015年 | 393篇 |
2014年 | 381篇 |
2013年 | 485篇 |
2012年 | 483篇 |
2011年 | 464篇 |
2010年 | 282篇 |
2009年 | 234篇 |
2008年 | 274篇 |
2007年 | 288篇 |
2006年 | 230篇 |
2005年 | 179篇 |
2004年 | 176篇 |
2003年 | 137篇 |
2002年 | 136篇 |
2001年 | 94篇 |
2000年 | 70篇 |
1999年 | 55篇 |
1998年 | 39篇 |
1997年 | 34篇 |
1996年 | 28篇 |
1995年 | 29篇 |
1994年 | 24篇 |
1993年 | 24篇 |
1992年 | 56篇 |
1991年 | 39篇 |
1990年 | 50篇 |
1989年 | 47篇 |
1988年 | 37篇 |
1987年 | 30篇 |
1986年 | 34篇 |
1985年 | 29篇 |
1984年 | 38篇 |
1983年 | 33篇 |
1982年 | 32篇 |
1981年 | 34篇 |
1980年 | 40篇 |
1979年 | 18篇 |
1978年 | 27篇 |
1977年 | 19篇 |
1975年 | 16篇 |
1974年 | 22篇 |
1973年 | 20篇 |
排序方式: 共有7007条查询结果,搜索用时 921 毫秒
151.
Russian Journal of Bioorganic Chemistry - An effective method for synthesizing a series of fifteen new compounds ethyl 3-(2-(3-amino-1,4-dihydroquinoxaline-2-carbonyl)hydrazono )butanoate (II),... 相似文献
152.
The molecular phylogenetic relationship among two species of genus Leiurus, from Saudi Arabia with additional comparative sequence data available from Egypt, Oman and Turkey is presented. The molecular phylogeny was performed using maximum parsimony, neighbor joining and bayesian inference. Our results indicate a clear deep splitting between the Western clade, which represented by L. quinuestriatus sequences from Egypt and those from the Eastern clade which encompassing different Leiurus species from Saudi Arabia, Oman and Turkey was shown. Also, the phylogenetic relationship represents additional support for the taxonomic status of Arabian Leiurus species. 相似文献
153.
Ibrar Ahmed Peter J. Lockhart Esperanza M. G. Agoo Kyaw W. Naing Dzu V. Nguyen Dilip K. Medhi Peter J. Matthews 《Ecology and evolution》2020,10(23):13530
As an ancient clonal root and leaf crop, taro (Colocasia esculenta, Araceae) is highly polymorphic with uncertain genetic and geographic origins. We explored chloroplast DNA diversity in cultivated and wild taros, and closely related wild taxa, and found cultivated taro to be polyphyletic, with tropical and temperate clades that appear to originate in Southeast Asia sensu lato. A third clade was found exclusively in wild populations from Southeast Asia to Australia and Papua New Guinea. Our findings do not support the hypothesis of taro domestication in Papua New Guinea, despite archaeological evidence for early use or cultivation there, and the presence of apparently natural wild populations in the region (Australia and Papua New Guinea). 相似文献
154.
Plant Cell, Tissue and Organ Culture (PCTOC) - Date palm (Phoenix dactylifera L.) micropropagation still faces many problems, such as reduced growth and development of callus, low multiplication... 相似文献
155.
156.
Baioumy Asmaa Ali Swelim Hamdy Hamed Ibrahim Ahmed Adly Mohamed Fatma El-Sayed Marzouk Aleya Soliman El-Alfy Sherif Helmy 《Experimental & applied acarology》2021,85(2-4):331-354
Experimental and Applied Acarology - This study examined the acaricidal, histopathological and genotoxic effects of the entomopathogenic fungus Beauveria bassiana on engorged females of the fowl... 相似文献
157.
Mohamed Yara Ahmed Hassaneen H. M. El-Dessouky Mohamed A. Safwat Gehan Hassan Naglaa Abu-Mandil Amr Khalda 《Molecular biology reports》2021,48(7):5497-5502
Molecular Biology Reports - A cluster of many risk factors for type 2 diabetes and cardiovascular disease is used to describe the metabolic syndrome (MetS). Moreover, genetic differences associated... 相似文献
158.
Kamal Laina Zarisa Mohd Adam Mowaffaq Adam Ahmed Shahpudin Siti Nurfatimah Mohd. Shuib Ahmad Naqeeb Sandai Rosline Hassan Norazian Mohd Tabana Yasser Basri Dayang Fredalina Than Leslie Thian Lung Sandai Doblin 《Mycopathologia》2021,186(2):221-236
Mycopathologia - Candida albicans has been reported globally as the most widespread pathogenic species contributing candidiasis from superficial to systemic infections in immunocompromised... 相似文献
159.
Khan Muhammad Tahir Zeb Muhammad Tariq Ahsan Hina Ahmed Abrar Ali Arif Akhtar Khalid Malik Shaukat Iqbal Cui Zhilei Ali Sajid Khan Anwar Sheed Ahmad Manzoor Wei Dong-Qing Irfan Muhammad 《Archives of microbiology》2021,203(1):59-66
Archives of Microbiology - Severe acute respiratory syndrome virus 2 (SARS-CoV-2) belongs to the single-stranded positive-sense RNA family. The virus contains a large genome that encodes four... 相似文献
160.
Farag Ola M. Abd-Elsalam Reham M. Ogaly Hanan A. Ali Sara E. El Badawy Shymaa A. Alsherbiny Muhammed A. Li Chun Guang Ahmed Kawkab A. 《Neurochemical research》2021,46(4):819-842
Neurochemical Research - Acrylamide (ACR) is an environmental pollutant with well-demonstrated neurotoxic and neurodegenerative effects in both humans and experimental animals. The present study... 相似文献