全文获取类型
收费全文 | 6214篇 |
免费 | 474篇 |
国内免费 | 10篇 |
出版年
2023年 | 20篇 |
2022年 | 79篇 |
2021年 | 124篇 |
2020年 | 95篇 |
2019年 | 112篇 |
2018年 | 145篇 |
2017年 | 116篇 |
2016年 | 222篇 |
2015年 | 349篇 |
2014年 | 374篇 |
2013年 | 417篇 |
2012年 | 570篇 |
2011年 | 513篇 |
2010年 | 323篇 |
2009年 | 285篇 |
2008年 | 411篇 |
2007年 | 370篇 |
2006年 | 324篇 |
2005年 | 298篇 |
2004年 | 294篇 |
2003年 | 239篇 |
2002年 | 221篇 |
2001年 | 91篇 |
2000年 | 71篇 |
1999年 | 88篇 |
1998年 | 49篇 |
1997年 | 41篇 |
1996年 | 25篇 |
1995年 | 18篇 |
1994年 | 28篇 |
1993年 | 14篇 |
1992年 | 30篇 |
1991年 | 31篇 |
1990年 | 19篇 |
1989年 | 30篇 |
1988年 | 27篇 |
1987年 | 24篇 |
1986年 | 24篇 |
1985年 | 17篇 |
1984年 | 15篇 |
1983年 | 10篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 12篇 |
1979年 | 13篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1975年 | 14篇 |
1974年 | 12篇 |
1973年 | 8篇 |
排序方式: 共有6698条查询结果,搜索用时 15 毫秒
971.
972.
973.
974.
Analysis of gemini pollen 3 mutant suggests a broad function of AUGMIN in microtubule organization during sexual reproduction in Arabidopsis
下载免费PDF全文
![点击此处可从《The Plant journal : for cell and molecular biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Sung‐Aeong Oh Jien Jeon Hyo‐Jin Park Paul Eivind Grini David Twell Soon Ki Park 《The Plant journal : for cell and molecular biology》2016,87(2):188-201
In flowering plants, male gametes arise via meiosis of diploid pollen mother cells followed by two rounds of mitotic division. Haploid microspores undergo polar nuclear migration and asymmetric division at pollen mitosis I to segregate the male germline, followed by division of the germ cell to generate a pair of sperm cells. We previously reported two gemini pollen (gem) mutants that produced twin‐celled pollen arising from polarity and cytokinesis defects at pollen mitosis I in Arabidopsis. Here, we report an independent mutant, gem3, with a similar division phenotype and severe genetic transmission defects through pollen. Cytological analyses revealed that gem3 disrupts cell division during male meiosis, at pollen mitosis I and during female gametophyte development. We show that gem3 is a hypomorphic allele (aug6‐1) of AUGMIN subunit 6, encoding a conserved component in the augmin complex, which mediates microtubule (MT)‐dependent MT nucleation in acentrosomal cells. We show that MT arrays are disturbed in gem3/aug6‐1 during male meiosis and pollen mitosis I using fluorescent MT‐markers. Our results demonstrate a broad role for the augmin complex in MT organization during sexual reproduction, and highlight gem3/aug6‐1 mutants as a valuable tool for the investigation of augmin‐dependent MT nucleation and dynamics in plant cells. 相似文献
975.
Sublingual immunization with Japanese encephalitis virus vaccine effectively induces immunity through both cellular and humoral immune responses in mice
下载免费PDF全文
![点击此处可从《Microbiology and immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Eun‐Young Lee Joo‐Young Kim Deuk‐Ki Lee Il‐Sub Yoon Hae Li Ko Ji‐Woo Chung Jun Chang Jae‐Hwan Nam 《Microbiology and immunology》2016,60(12):846-853
The Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis. Although there are four classes of vaccines against JEV, all of them are administered by s.c or i.m injection. Here, the effectiveness of sublingual (s.l.) administration of a JEV live‐attenuated vaccine or recombinant modified vaccinia virus Ankara (MVA) vaccine, including JEV prM/E, was investigated. The mice were immunized three times i.m. or s.c. One week after the final immunization by both s.l. and i.m. routes, the titers of IgG1 induced by the recombinant MVA vaccine were higher than those induced by the live‐attenuated vaccine, whereas the titers of IgG2a induced by the live‐attenuated vaccine were higher than those induced by the recombinant MVA vaccine. However, both vaccines induced neutralizing antibodies when given by either s.l. or i.m. routes, indicating that both vaccines induce appropriate Th1 and Th2 cell responses through the s.l. and i.m. routes. Moreover, both vaccines protected against induction of proinflammatory cytokines and focal spleen white pulp hyperplasia after viral challenge. Virus‐specific IFN‐γ+ CD4+ and CD8+ T cells appeared to increase in mice immunized via both s.l. and i.m. routes. Interestingly, virus‐specific IL‐17+ CD4+ T cells increased significantly only in the mice immunized via the s.l. route; however, the increased IL‐17 did not affect pathogenicity after viral challenge. These results suggest that s.l. immunization may be as useful as i.m. injection for induction of protective immune responses against JEV by both live‐attenuated and recombinant MVA vaccines. 相似文献
976.
977.
Chang Sun Kim Jong Woo Nam Jong Won Jo Sang-Yong Kim Jae-Gu Han Min Woo Hyun Gi-Ho Sung Sang-Kuk Han 《Journal of microbiology (Seoul, Korea)》2016,54(1):14-22
We surveyed macrofungi biweekly at defined plots from April to December in 2014, in the Mongolian oak-dominant forest, Gwangneung Forest, Pochen-si, Korea, and analyzed a soilhigher fungal diversity during four seasons (represented by April, August, October, and December). Based on morphological observation of collected specimens, the collected macrofungi were classified into 2 phyla 3 classes 7 orders, 14 families, 21 genera, and 33 species (36 specimens). DNA-based community analyses indicated that soil-higher fungi were classified into 2 phyla, 18 classes, 49 orders, 101 families, and 155 genera (83,360 sequence reads), defined herein as 155 genus-level operational taxonomic units (GOTUs). In the present study, we evaluated and discussed the fungal diversity in seasonal dynamics and soil layers based on collected macrofungi and pyrosequencing data while considering environmental parameters (pH, exchangeable K, T-P, NH 4 + , NO 3 - , OM, WR, TOC, and T-N). Moreover, principal components analysis (PCA) showed distinct clusters of the GOTU assemblage associated with the seasons. 相似文献
978.
Hackwon Do Chang Woo Lee Sung Gu Lee Hara Kang Chul Min Park Hak Jun Kim Hyun Park HaJeung Park Jun Hyuck Lee 《Journal of microbiology (Seoul, Korea)》2016,54(2):114-121
The gene product of dddC (Uniprot code G5CZI2), from the Gram-negative marine bacterium Oceanimonas doudoroffii, is a methylmalonate-semialdehyde dehydrogenase (OdoMMSDH) enzyme. MMSDH is a member of the aldehyde dehydrogenase superfamily, and it catalyzes the NADdependent decarboxylation of methylmalonate semialdehyde to propionyl-CoA. We determined the crystal structure of OdoMMSDH at 2.9 Å resolution. Among the twelve molecules in the asymmetric unit, six subunits complexed with NAD, which was carried along the protein purification steps. OdoMMSDH exists as a stable homodimer in solution; each subunit consists of three distinct domains: an NAD-binding domain, a catalytic domain, and an oligomerization domain. Computational modeling studies of the OdoMMSDH structure revealed key residues important for substrate recognition and tetrahedral intermediate stabilization. Two basic residues (Arg103 and Arg279) and six hydrophobic residues (Phe150, Met153, Val154, Trp157, Met281, and Phe449) were found to be important for tetrahedral intermediate binding. Modeling data also suggested that the backbone amide of Cys280 and the side chain amine of Asn149 function as the oxyanion hole during the enzymatic reaction. Our results provide useful insights into the substrate recognition site residues and catalytic mechanism of OdoMMSDH. 相似文献
979.
Sung-Gil Hong Jae Hyun Kim Ryang Eun Kim Seok-Joon Kwon Dae Woo Kim Hee-Tae Jung Jonathan S. Dordick Jungbae Kim 《Biotechnology and Bioprocess Engineering》2016,21(4):573-579
Glucose oxidase (GOx) was immobilized onto graphene oxide (GRO) via three different preparation methods: enzyme adsorption (EA), enzyme adsorption and crosslinking (EAC), and enzyme adsorption, precipitation and crosslinking (EAPC). EAPC formulations, prepared via enzyme precipitation with 60% ammonium sulfate, showed 1,980 and 1,630 times higher activity per weight of GRO than those of EA and EAC formulations, respectively. After 59 days at room temperature, EAPC maintained 88% of initial activity, while EA and EAC retained 42 and 45% of their initial activities, respectively. These results indicate that the steps of precipitation and crosslinking in the EAPC formulation are critical to achieve high enzyme loading and stability of EAPC. EA, EAC and EAPC were used to prepare enzyme electrodes for use as glucose biosensors. Optimized EAPC electrode showed 93- and 25-fold higher sensitivity than EA and EAC, respectively. To further increase the sensitivity of EAPC electrode, multi-walled carbon nanotubes (MWCNTs) were mixed with EAPC for the preparation of enzyme electrode. Surprisingly, the EAPC electrode with additional 99.5 wt% MWCNTs showed 7,800-fold higher sensitivity than the EAPC electrode without MWCNT addition. Immobilization and stabilization of enzymes on GRO via the EAPC approach can be used for the development of highly sensitive biosensors as well as to achieve high enzyme loading and stability. 相似文献
980.
Van Dung Pham Sivachandiran Somasundaram Seung Hwan Lee Si Jae Park Soon Ho Hong 《Biotechnology and Bioprocess Engineering》2016,21(2):261-267
Nylon 4 is a biodegradable polymer which can be produced from the monomer of pyrrolidone. Gammaaminobutyric acid (GABA) is a precursor of pyrrolidone used for the production of bioplastics. In this study, Escherichia coli were engineered to produce gammaaminobutyric acid from glucose via an alternative novel pathway by the introduction of synthetic scaffolds. The GABA pathway constructed contained succinate dehydrogenase, succinate-semialdehyde dehydrogenase and GABA aminotransferase to redirect the Krebs cycle flux to GABA production. By introduction of a synthetic scaffold, production of 0.64 g/L GABA was achieved at 30°C and pH 6.5. Final GABA concentration was increased by 11.3% via the inactivation of competing pathways, and higher initial glucose concentration led to the enhanced final GABA concentration of 1.01 g/L. 相似文献