全文获取类型
收费全文 | 1033篇 |
免费 | 84篇 |
国内免费 | 66篇 |
出版年
2024年 | 4篇 |
2023年 | 16篇 |
2022年 | 30篇 |
2021年 | 80篇 |
2020年 | 38篇 |
2019年 | 52篇 |
2018年 | 48篇 |
2017年 | 35篇 |
2016年 | 53篇 |
2015年 | 70篇 |
2014年 | 79篇 |
2013年 | 73篇 |
2012年 | 109篇 |
2011年 | 96篇 |
2010年 | 47篇 |
2009年 | 38篇 |
2008年 | 52篇 |
2007年 | 41篇 |
2006年 | 34篇 |
2005年 | 28篇 |
2004年 | 29篇 |
2003年 | 22篇 |
2002年 | 12篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 14篇 |
1998年 | 7篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 8篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有1183条查询结果,搜索用时 218 毫秒
151.
152.
A Novel Graphene Oxide Wrapped Na2Fe2(SO4)3/C Cathode Composite for Long Life and High Energy Density Sodium‐Ion Batteries
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mingzhe Chen David Cortie Zhe Hu Huile Jin Shun Wang Qinfen Gu Weibo Hua Enhui Wang Weihong Lai Lingna Chen Shu‐Lei Chou Xiao‐Lin Wang Shi‐Xue Dou 《Liver Transplantation》2018,8(27)
The cathode materials in the Na‐ion battery system are always the key issue obstructing wider application because of their relatively low specific capacity and low energy density. A graphene oxide (GO) wrapped composite, Na2Fe2(SO4)3@C@GO, is fabricated via a simple freeze‐drying method. The as‐prepared material can deliver a 3.8 V platform with discharge capacity of 107.9 mAh g?1 at 0.1 C (1 C = 120 mA g?1) as well as offering capacity retention above 90% at a discharge rate of 0.2 C after 300 cycles. The well‐constructed carbon network provides fast electron transfer rates, and thus, higher power density also can be achieved (75.1 mAh g?1 at 10 C). The interface contribution of GO and Na2Fe2(SO4)3 is recognized and studied via density function theory calculation. The Na storage mechanism is also investigated through in situ synchrotron X‐ray diffraction, and pseudocapacitance contributions are also demonstrated. The diffusion coefficient of Na+ ions is around 10?12–10?10.8 cm2 s?1 during cycling. The higher working voltage of this composite is mainly ascribed to the larger electronegativity of the element S. The research indicates that this well‐constructed composite would be a competitive candidate as a cathode material for Na‐ion batteries. 相似文献
153.
Peste des petits ruminants (PPR) is a highly contagious transboundary animal disease with a severe socio-economic impact on the livestock industry, particularly in poor countries where it is endemic. Full understanding of PPR virus (PPRV) pathobiology and molecular biology is critical for effective control and eradication of the disease. To achieve these goals, establishment of stable reverse genetics systems for PPRV would play a key role. Unfortunately, this powerful technology remains less accessible and poorly documented for PPRV. In this review, we discussed the current status of PPRV reverse genetics as well as the recent innovations and advances in the reverse genetics of other non-segmented negative-sense RNA viruses that could be applicable to PPRV. These strategies may contribute to the improvement of existing techniques and/or the development of new reverse genetics systems for PPRV. 相似文献
154.
Yanjun Xu Xiaoling Tong Junrong Yan Xue Wu Yang W. Shao Yun Fan 《Translational oncology》2018,11(6):1364-1369
Non–small cell lung cancer (NSCLC) with activating EGFR mutations in exon 19 and 21 typically responds to EGFR tyrosine kinase inhibitors (TKI); however, for some patients, responses last only a few months. The underlying mechanisms of such short responses have not been fully elucidated. Here, we sequenced the genomes of 16 short-term responders (SR) that had progression-free survival (PFS) of less than 6 months on the first-generation EGFR TKI and compared them to 12 long-term responders (LR) that had more than 24 months of PFS. All patients were diagnosed with advanced lung adenocarcinoma and harbored EGFR 19del or L858R mutations before treatment. Paired tumor samples collected before treatment and after relapse (or at the last follow-up) were subjected to targeted next-generation sequencing of 416 cancer-related genes. SR patients were significantly younger than LR patients (P < .001). Collectively, 88% of SR patients had TP53 variations compared to 13% of LR patients (P < .001). Additionally, 37.5% of SR patients carried EGFR amplifications compared to 8% of LR patients. Other potential primary resistance factors were also identified in the pretreatment samples of 12 SR patients (75%), including PTEN loss; BIM deletion polymorphism; and amplifications of EGFR, ERBB2, MET, HRAS, and AKT2. Comparatively, only three LR patients (25%) were detected with EGFR or AKT1 amplifications that could possibly exert resistance. The diverse preexisting resistance mechanisms in SR patients revealed the complexity of defining treatment strategies even for EGFR-sensitive mutations. 相似文献
155.
银杏光合与蒸腾特性的研究 总被引:24,自引:0,他引:24
通过测定银杏净光合速率、蒸腾速度、气孔阻力等生理指标和观测银杏叶片形态、解剖特征,结果表明:1.银杏光补偿点为76μmol.m^-1.s^-1,光饱和点为1040μmol.m^-2.s^-1。超过光饱和点后,随光照强度增加光合强度反而下降。2.银杏光合最佳温度为26℃。3.净光 速率的日变化呈“午休”型的双峰曲线变化,最高峰出现在10:00A.M.前后,次峰出现在6:00P.M.前后。4.蒸腾速度 相似文献
156.
Persistence and Periodic Solutions of a System of Two Competing Species with Functional Response 总被引:3,自引:0,他引:3
Dou Jiawei 《生物数学学报》1997,(1)
1IntroductionOneofthemOStnit~tingquestionsinrnathernaticalbiologyconcernsthesurvivalofspeCiesinecologiCalmodels.Perslstenceisanimportantconceptindabingwiththeseproblems.Therearemanyliteraturesaboutthedy'ndricsofdiffuSivecompetingspeCies,butthefunctionalresPOnseofthisfOITnhasnotbeenst'Udiedtoomuchyet.Inthispaper,weconsiderthepersistenceproblemforanonautonomoussystemoftwOcompetingspecieswithfunctionalreSPOnse,themodelweconsiderinthispaperishereallri(t),ail(t),D,(t)anda(t)areassumedtobecon… 相似文献
157.
Pan Zhang Jingwei Feng Yunjun Liao Junrong Cai Tao Zhou Mingliang Sun Jianhua Gao Kai Gao 《Biochemical and biophysical research communications》2018,495(3):2249-2256
Background
Flap necrosis due to insufficient blood supply is a common postoperative complication in random pattern flaps. Stem cell therapies have emerged as promising biologics for tissue ischemia. A novel fat derived product, stromal vascular fraction gel (SVF-gel), can be prepared with lipoaspirate through simple mechanical processing, removing only the lipid content. SVF-gel enriches adipose-derived stem cells and potentially beneficial for flap necrosis.Methods
Nude mice ischemic flaps were treated with human SVF-gel, stromal vascular fraction (SVF) cell suspension or saline (n = 10). They were injected to the flap recipient beds, and necrosis and vascularization was assessed on postoperative day 14. We harvested the necrosis-free distal to evaluated skin healthiness and neovasculogenesis by Masson's trichrome stain and immunofluorescence, etc. Pro-angiogenic factors were assessed with tissue qRT-PCR. Finally, we traced the grafted human tissue with immunofluorescence.Results
SVF-gel-treated flaps have the smallest necrotic zones (22.05% ± 0.0438) compared with the saline controls (53.78% ± 0.1412) or SVF-treated ones (35.54% ± 0.0850, p = 0.039). Numerous functional musculocutaneous perforators were developed around SVF-gel grafts. The SVF-gel-treated skin had the best fat restoration (231.3 ± 48.1 μm) among three groups (F = 10.83, p = 0.0102) while saline-treated flap distal appeared fibrotic. SVF-gel-treated flaps also had ~43% more CD31 + capillaries (p = 0.0152) with ~3 folds more gene expression of angiogenic cytokines of VEGF and bFGF (p = 0.0310 and 0.0303, respectively) than saline-treated controls. Furthermore, we found hSVF-gel cells (hGolgi+) had directly engrafted as vessel component (α-smooth muscle actin, α-SMA+) to the flap.Conclusion
Adipose cellular matrix enhanced flap neovascularization partly by direct incorporation, improved flap survival and fat restoration. The composition-selective fat grafting with SVF-gel demonstrated efficacy comparable with stem cell therapy and is especially valuable for clinical translation. 相似文献158.
Alendronate induces osteoclast precursor apoptosis via peroxisomal dysfunction mediated ER stress
下载免费PDF全文
![点击此处可从《Journal of cellular physiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
159.
160.