全文获取类型
收费全文 | 11481篇 |
免费 | 758篇 |
国内免费 | 16篇 |
出版年
2024年 | 11篇 |
2023年 | 34篇 |
2022年 | 139篇 |
2021年 | 204篇 |
2020年 | 143篇 |
2019年 | 170篇 |
2018年 | 261篇 |
2017年 | 227篇 |
2016年 | 417篇 |
2015年 | 609篇 |
2014年 | 773篇 |
2013年 | 806篇 |
2012年 | 974篇 |
2011年 | 914篇 |
2010年 | 558篇 |
2009年 | 509篇 |
2008年 | 723篇 |
2007年 | 666篇 |
2006年 | 648篇 |
2005年 | 565篇 |
2004年 | 544篇 |
2003年 | 473篇 |
2002年 | 421篇 |
2001年 | 228篇 |
2000年 | 202篇 |
1999年 | 156篇 |
1998年 | 75篇 |
1997年 | 65篇 |
1996年 | 49篇 |
1995年 | 59篇 |
1994年 | 37篇 |
1993年 | 32篇 |
1992年 | 68篇 |
1991年 | 36篇 |
1990年 | 46篇 |
1989年 | 43篇 |
1988年 | 39篇 |
1987年 | 29篇 |
1986年 | 24篇 |
1985年 | 32篇 |
1984年 | 28篇 |
1983年 | 17篇 |
1982年 | 20篇 |
1981年 | 15篇 |
1979年 | 24篇 |
1978年 | 20篇 |
1976年 | 14篇 |
1974年 | 19篇 |
1973年 | 16篇 |
1972年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Mi Seon Park Hyun Suk Shin Gyung-Suk Kil Jehee Lee Cheol Young Choi 《Ichthyological Research》2011,58(3):195-201
We examined changes in the expression of Na+/K+-ATPase mRNA in the gills of the cinnamon clownfish using quantitative real-time PCR in an osmotically changing environment
[seawater (35 psu; practical salinity unit, 1 psu ≈ 1‰) → brackish water (17.5 psu) and brackish water with prolactin]. The
expression of Na+/K+-ATPase mRNA in gills was increased after the transfer to brackish water, and the expression was repressed by prolactin treatment.
Also, activities of gill Na+/K+-ATPase and plasma cortisol levels increased after the transfer to brackish water and were repressed in brackish water with
prolactin treatment. Na+/K+-ATPase-immunoreactive cells were almost consistently observed in the gill filaments, but absent from the lamella epithelia.
The plasma osmolality level decreased in brackish water, but the level of this parameter increased in brackish water with
prolactin treatment during salinity change. These results suggest that the Na+/K+-ATPase gene plays an important role in osmoregulation in gills, and prolactin improves the hyperosmoregulatory ability of
cinnamon clownfish in a brackish water (hypoosmotic) environment. 相似文献
992.
Marta De Zotti Barbara Biondi Cristina Peggion Yoonkyung Park Kyung‐Soo Hahm Fernando Formaggio Claudio Toniolo 《Journal of peptide science》2011,17(8):585-594
The medium‐length peptaibiotics are characterized by a primary structure of 14–16 amino acid residues. Despite the interesting antibiotic and antifungal properties exhibited by these membrane‐active peptides, their exact mechanism of action is still unknown. Here, we present our results on heptaibin, a 14‐amino acid peptaibiotic found to exhibit antimicrobial activity against Staphylococcus aureus. We carried out the very challenging synthesis of heptaibin on solid phase and a detailed conformational analysis in solution. The peptaibiotic is folded in a mixed 310‐/α‐helix conformation which exhibits a remarkable amphiphilic character. We also find that it is highly stable toward degradation by proteolytic enzymes and nonhemolytic. Finally, fluorescence leakage experiments using small unilamellar vesicles of three different compositions revealed that heptaibin, although uncharged, is a selective compound for permeabilization of model membranes mimicking the overall negatively charged surface of Gram‐positive bacteria. This latter finding is in agreement with the originally published antimicrobial activity data. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
993.
994.
E-Hyun Shin Chan Park Hyun kyung Kim Dong-Kyu Lee Soon-Il Kim Hyesook Kang Kyu-Sik Chang 《Journal of Asia》2011,14(3):233-236
Field-collected populations of mayflies, Ephemera orientalis were tested for susceptibility to 10 different insecticides using a direct-contact mortality bioassay. Ephemera orientalis subimagoes were susceptible to the insecticides chlorpyrifos, fenitrothion and chlorfenapyr with LD50 values of 69.7, 78.8 and 81.9 μg/♀, and adults had LD50 values of 71.9, 78.8 and 85.4 μg/♀, respectively. Susceptibility ratios (SRs) of subimagoes and adults of E. orientalis to the 10 insecticides were 1.0 to1.2 folds. The mayflies showed higher susceptibility to organophosphates than to pyrethroids. The SRs of Anopheles sinensis to E. orientalis were 514 to 1438 folds higher for organophosphates (LD50 values of 0.05 to 0.23 μg/♀) and 62 to 1155 folds higher for pyrethroids (LD50 values of 0.13 to 2.41 μg/♀). The SRs of Culex pipiens to E. orientalis were 606 to 3595 folds higher for organophosphates with LD50 values of 0.02–0.17 μg/♀ and 81 to 1365 folds higher for pyrethroids with LD50 values of 0.11–1.83 μg/♀. These results indicate that the use of ineffective insecticides will result in unsatisfactory control against field populations of the subimagoes and adults of E. orientalis. 相似文献
995.
Hyun Na Koo Sung Min Bae Jae Bang Choi Tae Young Shin Bit Na Rae Yun Jae Young Choi Kwang Sik Lee Jong Yul Roh Yeon Ho Je Byung Rae Jin Sung Sik Yoo Jae Su Kim Young In Kim In Joong Yoon Soo Dong Woo 《Journal of Asia》2011,14(1):107-117
To characterize the NYJ strain of pseudorabies virus (PRV; Alphaherpesvirus of swine) isolated from the serum of an infected swine in Korea, the nucleotide sequence of three major glycoproteins (gB, gC, and gD) was analyzed. The expression of most potent immunogenic glycoprotein (gD) was also investigated using a Bombyx mori nucleopolyhedrovirus (BmNPV) expression system. The length of the glycoprotein genes corresponding to gB, gC, and gD of the NYJ strain were 2751 bp, 1443 bp, and 1203, respectively, and their identity ranged from 94.2% to 99.8% when compared with other strains. Phylogenetic analyses using these sequences showed that the NYJ strain forms a distinct branch with high bootstrap support. A novel transfer vector (pBmKSK4) was engineered with the polyhedrin promoter of BmNPV and a 6xHis tag to express glycoprotein gD in Bm5 cells and silkworm, B. mori, larvae. The immunogenicity of recombinant gD was demonstrated by its specific detection in both Bm5 cells and silkworm larvae by porcine anti-PRV antibody. The results of this study have implications both for the taxonomy of Korean PRV strains and vaccine development. 相似文献
996.
This study was designed to evaluate the effect of autologous bone marrow mesenchymal stem cells (MSCs) seeded into Gelfoam® on structural bone allograft healing. Thirty New Zealand white rabbits were divided into two groups. Segmental bone defect was created on diaphysis of the femur, and the defect was reconstructed with structural bone allograft. In experimental group, structural allograft was wrapped around by Gelfoam® containing autologous MSCs, whereas cells were not included in control group. At 4, 8, 12 weeks, the femur of rabbits underwent radiographic and histologic evaluation for bony union. Bone morphogenic protein-2 (BMP-2), BMP-4, BMP-7, vascular endothelial growth factor (VEGF), and receptor activator of nuclear factor-kappa B ligand (RANKL) were measured within the grafted periosteal tissue. Bony union was not achieved in both groups at 4 and 8 weeks. At 12 weeks, three out of five femurs in experimental group were united, but one out of five in control group was united. Mean Taira scores were significantly different between two groups. The expression of BMP-2 was significantly higher at 4, 8 weeks, the expressions of BMP-4 and BMP-7 were significantly higher at 8 and 12 weeks, and the expression of VEGF and RANKL were significantly higher at all time points in experimental group. Incorporation of the structural bone allograft could be enhanced if allograft is covered with Gelfoam® containing autologous MSCs. MSCs have influence on not only bone formation, but neo-angiogenesis, and bone resorption. 相似文献
997.
Alan Soo David G. Healy Hatim El-Bashier Sandra Shaw Alfred E. Wood 《Cell and tissue banking》2011,12(3):185-190
Human donor heart valves remain essential for many reconstructive heart procedures. Heart valve donations are a scarce resource
which must be used efficiently and safely. Infection transmission remains a potential risk with homograft valve use. Early
experience with homograft valves identified high rates of microbial contamination at collection and initiated the practise
of immersion in an antibiotic cocktail. Many centres rely on the microbiology screening after exposure to the antibiotic cocktail.
We in our centre accept or reject valves on the basis of the microbiology screening at the time of collection prior to immersion
in antibiotic solution. We wanted to compare our rate of valve discard and the rate of microbial contamination at implant
with other centres. Valves are collected for the Irish Heart Valve Tissue Bank through partnership between the National Centre
for Cardiothoracic Surgery and the Irish Blood Transfusion Service. Valves are collected in a surgical theatre setting and
processed in dedicated section of the Irish Blood Transfusion Board. Tissues are screening for microbiology at collection
and also at implantation. A total of 564 human heart valves and valve conduits were processed through the service during the
study period. 167 (29.6%) were discarded during the processing and storage stages. The major reason for this in 117 cases
was unsatisfactory microbiology on initial tissue screening. Repeat screening of accepted valves at the time of implantation
identified positive cultures in only 0.9%. Optimal use of these limited resources is clearly important. However recipient
safety remains paramount. One-fifth of collected valves are discarded at the processing stage due to positive microbiology
screening. This is a higher rate of discard then other centres which reject 5.6–10% due to positive microbiology. However
our rate of contamination at time of implant is lower then the 3% rate reported elsewhere. We are satisfied that our current
discard rate, although significant, reflects rigorous quality control and the optimal balance between valve availability and
patient safety. 相似文献
998.
999.
Liu T Ortiz JA Taing L Meyer CA Lee B Zhang Y Shin H Wong SS Ma J Lei Y Pape UJ Poidinger M Chen Y Yeung K Brown M Turpaz Y Liu XS 《Genome biology》2011,12(8):R83-10
The increasing volume of ChIP-chip and ChIP-seq data being generated creates a challenge for standard, integrative and reproducible bioinformatics data analysis platforms. We developed a web-based application called Cistrome, based on the Galaxy open source framework. In addition to the standard Galaxy functions, Cistrome has 29 ChIP-chip- and ChIP-seq-specific tools in three major categories, from preliminary peak calling and correlation analyses to downstream genome feature association, gene expression analyses, and motif discovery. Cistrome is available at http://cistrome.org/ap/. 相似文献
1000.
Yu W Chan-On W Teo M Ong CK Cutcutache I Allen GE Wong B Myint SS Lim KH Voorhoeve PM Rozen S Soo KC Tan P Teh BT 《Genome biology》2011,12(9):R96-14