全文获取类型
收费全文 | 6563篇 |
免费 | 475篇 |
出版年
2024年 | 8篇 |
2023年 | 35篇 |
2022年 | 67篇 |
2021年 | 205篇 |
2020年 | 114篇 |
2019年 | 156篇 |
2018年 | 182篇 |
2017年 | 149篇 |
2016年 | 263篇 |
2015年 | 382篇 |
2014年 | 402篇 |
2013年 | 495篇 |
2012年 | 568篇 |
2011年 | 526篇 |
2010年 | 346篇 |
2009年 | 324篇 |
2008年 | 391篇 |
2007年 | 406篇 |
2006年 | 309篇 |
2005年 | 275篇 |
2004年 | 287篇 |
2003年 | 244篇 |
2002年 | 245篇 |
2001年 | 81篇 |
2000年 | 50篇 |
1999年 | 59篇 |
1998年 | 74篇 |
1997年 | 56篇 |
1996年 | 30篇 |
1995年 | 33篇 |
1994年 | 38篇 |
1993年 | 23篇 |
1992年 | 35篇 |
1991年 | 27篇 |
1990年 | 21篇 |
1989年 | 16篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 9篇 |
1985年 | 14篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1961年 | 3篇 |
排序方式: 共有7038条查询结果,搜索用时 93 毫秒
81.
82.
83.
Jose Luis Martinez-Sande Javier Garcia-Seara Laila Gonzalez-Melchor Moises Rodriguez-Mañero Aurora Baluja Xesus Alberte Fernandez-Lopez Jose Ramon Gonzalez Juanatey 《Indian pacing and electrophysiology journal》2021,21(2):89-94
PurposeDespite the developments in conventional transvenous pacemakers (VVI-PM), the procedure is still associated with significant complications. Although there are no prospective clinical trials that compared VVI-PM with transcatheter pacemaker systems (TPS).MethodsThis is a prospective, observational, single-center study that included all patients with an indication for a single-chamber pacemaker implant within a 4-year period. All clinical, ECG and echocardiographic characteristics at implant, electrical parameters, associated complications and mortality were analyzed. A Cox survival model and a Bayesian cohort analysis were performed for differences in complication rates between groups.ResultsThere were 443 patients included (198 TPS and 245 VVI-PM). The mean age was 81.5 years (TPS group, 79.2 ± 6.6 years; VVI-PM group, 83.5 ± 8.9 years). There was a male predominance in TPS group (123, 62.1% vs. 67, 27.3%; p < 0.001). The presence of systolic dysfunction and renal insufficiency were more frequent in VVI-PM group than in TPS patients. Mean follow-up was 22.3 ± 15.9 months. In a multivariable paired data the TPS group presented fewer complications than VVI-PM group (HR = 0.39 [0.15–0.98], p-value 0.013), but major complications were not different (6, 3% vs 14, 5.6% respectively, p = 0.1761). There was no difference in the mortality rate between the groups. The TPS group had less risk than VVI-PM group to have a complication, with a 96% of probability.ConclusionsTPS patients had a lower overall complication rate than VVI-PM patients including matched-pair samples using a Bayesian analysis. These results confirm the safety profile of TPS in clinical practice. 相似文献
84.
85.
Reactive oxygen species are toxic byproducts of aerobic respiration that are also important in mediating a diversity of cellular functions. Reactive oxygen species form an important component of plant defenses to inhibit microbial pathogens during pathogen–plant interactions. Tolerance to oxidative stress is likely to make a significant contribution to the viability and pathogenicity of plant pathogens, but the complex network of oxidative stress responses hinders identification of the genes contributing to this trait. Here, we employed a forward genetic approach to investigate the genetic architecture of oxidative stress tolerance in the fungal wheat pathogen Zymoseptoria tritici. We used quantitative trait locus (QTL) mapping of growth and melanization under axenic conditions in two cross-populations to identify genomic regions associated with tolerance to oxidative stress. We found that QTLs associated with growth under oxidative stress as well as inherent growth can affect oxidative stress tolerance, and we identified two uncharacterized genes in a major QTL associated with this trait. Our data suggest that melanization does not affect tolerance to oxidative stress, which differs from what was found for animal pathogens. This study provides a whole-genome perspective on the genetic basis of oxidative stress tolerance in a plant pathogen. 相似文献
86.
87.
Gabriella Galatà Andrés C. García-Montero Thomas Kristensen Ahmed A.Z. Dawoud Javier I. Muñoz-González Manja Meggendorfer Paola Guglielmelli Yvette Hoade Ivan Alvarez-Twose Christian Gieger Konstantin Strauch Luigi Ferrucci Toshiko Tanaka Stefania Bandinelli Theresia M. Schnurr Torsten Haferlach Sigurd Broesby-Olsen Hanne Vestergaard William J. Tapper 《American journal of human genetics》2021,108(2):284-294
88.
89.
Brett Jestrow William Cinea Brígido Peguero Chad Husby Javier Francisco‐Ortega 《Curtis's Botanical Magazine》2021,38(1):3-18
Clavija domingensis Urb. & Ekman was one of the many Haitian endemics that were described based on collections made by the great Swedish botanist Leonard Ekman between 1924 and 1928. The species is Critically Endangered sensu IUCN (criteria c2a(i); D) and it is currently the focus of conservation initiatives in Jardin Botanique des Cayes (Haiti), Jardín Botánico Nacional Dr. Rafael M. Moscoso (Dominican Republic), and Fairchild Tropical Botanic Garden (U.S.A.). Now known from only six localities from southern Haiti, each locality only represents a single individual. The species is illustrated based on plants grown in Fairchild Tropical Botanic Garden. 相似文献
90.
Alonso Alberto Pérez Javier Monroy Silvia López-Rojo Naiara Basaguren Ana Bosch Jaime Boyero Luz 《Ecosystems》2021,24(6):1436-1449
Ecosystems - Leaf litter of alder (Alnus glutinosa) is a key resource to detrital stream food webs. Due to its high quality and palatability, it is readily colonised by microorganisms and consumed... 相似文献