全文获取类型
收费全文 | 3684篇 |
免费 | 213篇 |
国内免费 | 11篇 |
出版年
2023年 | 33篇 |
2022年 | 81篇 |
2021年 | 134篇 |
2020年 | 69篇 |
2019年 | 79篇 |
2018年 | 107篇 |
2017年 | 114篇 |
2016年 | 125篇 |
2015年 | 174篇 |
2014年 | 232篇 |
2013年 | 271篇 |
2012年 | 269篇 |
2011年 | 259篇 |
2010年 | 161篇 |
2009年 | 129篇 |
2008年 | 183篇 |
2007年 | 156篇 |
2006年 | 129篇 |
2005年 | 131篇 |
2004年 | 123篇 |
2003年 | 110篇 |
2002年 | 85篇 |
2001年 | 59篇 |
2000年 | 54篇 |
1999年 | 56篇 |
1998年 | 32篇 |
1997年 | 12篇 |
1996年 | 17篇 |
1995年 | 22篇 |
1994年 | 19篇 |
1993年 | 22篇 |
1992年 | 32篇 |
1991年 | 39篇 |
1990年 | 32篇 |
1989年 | 23篇 |
1988年 | 20篇 |
1987年 | 20篇 |
1986年 | 20篇 |
1985年 | 18篇 |
1984年 | 15篇 |
1983年 | 17篇 |
1982年 | 18篇 |
1980年 | 14篇 |
1979年 | 15篇 |
1976年 | 14篇 |
1975年 | 15篇 |
1974年 | 24篇 |
1973年 | 13篇 |
1972年 | 11篇 |
1970年 | 17篇 |
排序方式: 共有3908条查询结果,搜索用时 15 毫秒
91.
92.
Kumari Anjali Ameri Shijin Marraiki Najat Elgorban Abdallah M. Aroulmoji Vincent Ponnuchamy Kumar Govarthanan Muthusamy Selvankumar Thangaswamy 《International journal of peptide research and therapeutics》2021,27(1):385-395
International Journal of Peptide Research and Therapeutics - The conopeptides are the conotoxin of Conus loroisii have wide applications in drug development. This work emphasizes the isolation and... 相似文献
93.
Bhanu Raj Meena Sanjeev Meena Deepali Chittora Kanika Sharma 《Biochemistry and Biophysics Reports》2021
Alternaria solani, a plant pathogenic fungus causes significant economical losses of potato crop. The disease is controlled primarily through some traditional methods and most commonly via the application of chemical fungicides. Fungicides treatment is not protected as chemicals pollute environment, effect health vulnerability in humans and when these harmful chemicals enter into the food chain become hazardous to all living entities. Recent efforts have focused on developing environmentally safe, long-lasting, and effective biocontrol methods for the management of plant diseases. Present research focus on screening of crude and partially purified leaf extract of Thevetia peruviana for the presence of antifungal efficacy against Alternarai solani. It was observed that 100% alcoholic crude and alcoholic fraction of partially purified extract showed maximum inhibitory activity which is due to the presence of different secondary metabolites, revealed by phytochemical screening. Active column fraction (possess best antifungal activity against Alternaria solani) was subjected to Gas Chromatography-Mass Spectrometry (GS-MS) analysis. On the basis of peaks matching of GC-MS chromatogram with available data base showed the presence of benzoic acid and oxo-benzoate in active fraction of Thevetia peruviana leaf extract which is already known chemical among the phytochemicals described for antimicrobial activity. Further research on development of herbal formulation from the same would be very helpful environment friendly approach to manage concern crop disease. 相似文献
94.
95.
96.
97.
N. Madan N. Sundar Raj M.A. Farook S. Vimal C. Venkatesan S. Abdul Majeed K.S.N. Nambi A.S. Sahul Hameed 《Process Biochemistry》2013,48(12):1893-1898
Hepatopancreatic Parvovirus (HPV) causes infection in the early stages of shrimp leading to retarded growth, ultimaltely resulting in monetary loss to the shrimp farmers. To over come this situation screening of post-larvae (PL) by immunology-based diagnostics is required. Hence, the specific gene of capsid protein for HPV was cloned into pRSET B expression vector and rHCP overexpressed with 6-histidine tagged fusion protein in Escherichia coli BL21(DE3). Immunology-based methods like Western blot, dot blot and ELISA techniques were employed to detect HPV in infected samples using the antiserum raised in rabbits against recombinant HCP of HPV. The dot blot assay using anti-rHCP was found to be capable of detecting HPV in HPV infected post-larvae as early as at 24 h post infection. The antiserum could detect the HPV in the infected samples at 1 ng of total protein. HPV infection estimated by ELISA using anti-HCP and pure r-HCP as a standard was found to increase gradually during the course of infection from 24 h post infection. The sensitivity of antibody-based diagnostics employed in the present study was compared with that of PCR diagnostic method to screen the post-larvae for the detection of HPV. 相似文献
98.
Hitesh Jagani Josyula Venkata Rao Vasanth Raj Palanimuthu Raghu Chandrashekar Hariharapura Sagar Gang 《Cellular & molecular biology letters》2013,18(1):120-136
Overexpression of anti-apoptotic Bcl-2 is often observed in a wide variety of human cancers. It prevents the induction of apoptosis in neoplastic cells and contributes to resistance to chemotherapy. RNA interference has emerged as an efficient and selective technique for gene silencing. The potential to use small interfering RNA (siRNA) as a therapeutic agent for the treatment of cancer has elicited a great deal of interest. However, insufficient cellular uptake and poor stability have limited its therapeutic applications. The purpose of this study was to prepare chitosan nanoparticles via ionic gelation of chitosan by tripolyphosphate for effective delivery of siRNA to silence the anti-apoptotic Bcl-2 gene in neoplastic cells. Chitosan nanoparticles loaded with siRNA were in the size range 190 to 340 nm with a polydispersive index ranging from 0.04 to 0.2. They were able to completely bind with siRNA, provide protection against nuclease degradation, and enhance the transfection. Cell culture studies revealed that nanoparticles with entrapped siRNA could efficiently silence the antiapoptotic Bcl-2 gene. Studies on Swiss albino mice showed that siRNA could be effectively delivered through nanoparticles. There was significant decrease in the tumor volume. Blocking the expression of anti-apoptotic Bcl-2 can enhance the sensitivity of cancerous cells to anti-cancer drugs and the apoptosis rate. Therefore, nanoformulations with siRNA can be promoted as an adjuvant therapy in combination with anti-cancer drugs. 相似文献
99.
100.
Douglas V. Dolfi Kathleen D. Mansfield Raj K. Kurupati Senthil Kannan Susan A. Doyle Hildegund C. J. Ertl Kenneth E. Schmader E. John Wherry 《PloS one》2013,8(10)
Current yearly influenza virus vaccines induce strain-specific neutralizing antibody (NAb) responses providing protective immunity to closely matched viruses. However, these vaccines are often poorly effective in high-risk groups such as the elderly and challenges exist in predicting yearly or emerging pandemic influenza virus strains to include in the vaccines. Thus, there has been considerable emphasis on understanding broadly protective immunological mechanisms for influenza virus. Recent studies have implicated memory CD4 T cells in heterotypic immunity in animal models and in human challenge studies. Here we examined how influenza virus vaccination boosted CD4 T cell responses in younger versus aged humans. Our results demonstrate that while the magnitude of the vaccine-induced CD4 T cell response and number of subjects responding on day 7 did not differ between younger and aged subjects, fewer aged subjects had peak responses on day 14. While CD4 T cell responses were inefficiently boosted against NA, both HA and especially nucleocaspid protein- and matrix-(NP+M) specific responses were robustly boosted. Pre-existing CD4 T cell responses were associated with more robust responses to influenza virus NP+M, but not H1 or H3. Finally pre-existing strain-specific NAb decreased the boosting of CD4 T cell responses. Thus, accumulation of pre-existing influenza virus-specific immunity in the form of NAb and cross-reactive T cells to conserved virus proteins (e.g. NP and M) over a lifetime of exposure to infection and vaccination may influence vaccine-induced CD4 T cell responses in the aged. 相似文献