全文获取类型
收费全文 | 7950篇 |
免费 | 415篇 |
国内免费 | 61篇 |
专业分类
耳鼻咽喉 | 65篇 |
儿科学 | 228篇 |
妇产科学 | 191篇 |
基础医学 | 1116篇 |
口腔科学 | 196篇 |
临床医学 | 634篇 |
内科学 | 1837篇 |
皮肤病学 | 177篇 |
神经病学 | 929篇 |
特种医学 | 399篇 |
外科学 | 887篇 |
综合类 | 36篇 |
预防医学 | 381篇 |
眼科学 | 172篇 |
药学 | 525篇 |
中国医学 | 38篇 |
肿瘤学 | 615篇 |
出版年
2024年 | 13篇 |
2023年 | 83篇 |
2022年 | 149篇 |
2021年 | 234篇 |
2020年 | 134篇 |
2019年 | 186篇 |
2018年 | 243篇 |
2017年 | 179篇 |
2016年 | 193篇 |
2015年 | 234篇 |
2014年 | 282篇 |
2013年 | 349篇 |
2012年 | 554篇 |
2011年 | 575篇 |
2010年 | 350篇 |
2009年 | 326篇 |
2008年 | 507篇 |
2007年 | 533篇 |
2006年 | 540篇 |
2005年 | 484篇 |
2004年 | 488篇 |
2003年 | 470篇 |
2002年 | 403篇 |
2001年 | 86篇 |
2000年 | 67篇 |
1999年 | 91篇 |
1998年 | 89篇 |
1997年 | 71篇 |
1996年 | 54篇 |
1995年 | 44篇 |
1994年 | 28篇 |
1993年 | 36篇 |
1992年 | 29篇 |
1991年 | 25篇 |
1990年 | 23篇 |
1989年 | 33篇 |
1988年 | 32篇 |
1987年 | 24篇 |
1986年 | 19篇 |
1985年 | 11篇 |
1984年 | 16篇 |
1983年 | 16篇 |
1982年 | 16篇 |
1981年 | 9篇 |
1979年 | 13篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1974年 | 7篇 |
1970年 | 10篇 |
1967年 | 7篇 |
排序方式: 共有8426条查询结果,搜索用时 15 毫秒
91.
92.
Nora I. Schneider Wolfgang Plieschnegger Michael Geppert Bernd Wigginghaus Gabriele M. Höss Andreas Eherer Eva-Maria Wolf Peter Rehak Michael Vieth Cord Langner 《Virchows Archiv : an international journal of pathology》2013,463(5):643-650
Pancreatic acinar cells are a well-recognized finding at the gastroesophageal junction, but their histogenesis and biological significance are unclear. From the prospective Central European multicenter histoGERD trial, we recruited 1,071 individuals undergoing gastroscopy for various non-selected reasons. Biopsy material was systematically sampled from the gastroesophageal junction and from the stomach. The study aimed to assess the prevalence of pancreatic acinar cells and to relate their presence to various histologic and clinical features. Overall, pancreatic acinar cells were observed in 184 (17.2 %) participants. Individuals diagnosed with pancreatic acinar cells were slightly younger than those without (median 50 vs. 53 years; p?=?0.009). There was no association with patients’ symptoms and/or complaints or with an endoscopic diagnosis of esophagitis or Barrett’s esophagus. Regarding histology, pancreatic acinar cells were not associated with features of the squamous epithelium indicating reflux disease, such as basal cell hyperplasia, papillary elongation, dilation of intercellular spaces, and inflammatory cell number, but were associated with the presence of cardiac mucosa (p?<?0.001), oxyntocardiac mucosa (p?<?0.001), and intestinal metaplasia (p?=?0.038), respectively. No association with Helicobacter pylori infection or diagnosis of gastritis was noted. In conclusion, pancreatic acinar cells are a common finding at the gastroesophageal junction, and no association with either reflux disease (histologically or endoscopically) or diagnosis of gastritis was observed. These data suggest a congenital rather than an acquired (metaplastic) origin of pancreatic acinar cells at the gastroesophageal junction. This questions the term “pancreatic acinar metaplasia” which is currently widely used for their diagnosis. 相似文献
93.
94.
95.
Gabriele Caselli Antonella Gemelli Cristina Ferrari Daniela Beltrami Alessia Offredi Giovanni M. Ruggiero Sandra Sassaroli Marcantonio M. Spada 《Clinical psychology & psychotherapy》2021,28(2):355-363
Permissive beliefs relate to the acceptability of engaging in alcohol use in spite of obvious potential negative consequences. They are considered the most proximal and precipitating cognitive factor in the decision to use alcohol and/or the activation of strategies to obtain it. Recent research suggested that ‘desire thinking’ may be involved in the escalation of craving and addictive behaviours and can play a role in strengthening permissive beliefs. The current study tested whether the induction of desire thinking would have a stronger effect on rate of conviction in permissive beliefs compared to a control cognitive response in the form of neutral thinking and whether this effect would be specific for patients with alcohol use disorder (AUD). Thirty AUD patients and 30 social drinkers (SD) were randomly allocated to two thinking manipulation tasks (desire thinking and neutral thinking). Current permissive beliefs were measured before and after manipulation and after a resting phase. Findings showed that desire thinking increased the level of current permissive beliefs after manipulation relative to the neutral thinking condition for the AUD group but not for the SD group. This effect was not purely dependent on the concurrent level of perceived craving. This study supports a causal relationship between the induction of desire thinking and rate of conviction in permissive beliefs and highlights the relevance of targeting desire thinking in the treatment for AUD patients. 相似文献
96.
97.
Marco Sangermano Paolo Allia Paola Tiberto Gabriele Barrera Federica Bondioli Nicola Florini Massimo Messori 《Macromolecular chemistry and physics.》2013,214(4):508-516
Magnetite nanoparticles were prepared by a non‐hydrolytic sol–gel (NHSG) process in the presence of benzyl alcohol. The obtained magnetite suspensions were mixed with an aliphatic epoxy resin and the formulations were photo‐polymerized to achieve composite materials with magnetic properties. The prepared magnetite nanoparticles and epoxy composites were fully characterized in terms of their magnetic properties. 相似文献
98.
Andrea Cortona Gabriele Rossini Simone Parrini Andrea Deregibus Tommaso Castroflorio 《The Angle orthodontist》2020,90(2):247
Objective:To evaluate, using the finite element method, the orthodontic rotational movement of a lower second premolar obtained with clear aligners, analyzing different staging and attachment configurations.Materials and Methods:A CAD model including a complete lower dental arch (with element 4.5 mesially rotated 30°) and the corresponding periodontal ligaments, attachments, and aligner was designed and imported to finite element software. Starting from the CAD model, six projects were created to simulate the following therapeutic combinations for correcting element 4.5 position: (1) without attachments, (2) single attachment placed on the buccal surface of element 4.5, (3) three attachments placed on the buccal surfaces of teeth 4.4 to 4.6. For each project, both 1.2° and 3° of aligner activation were considered.Results:All the analyzed configurations revealed a clockwise rotation movement of element 4.5 on the horizontal plane. Models with attachments showed a greater tooth displacement pattern than models without attachments. Simulations with attachments and 3° of aligner activation exhibited the best performance concerning tooth movement but registered high stresses in the periodontal ligaments, far from the ideal stress levels able to produce tooth rotational movement.Conclusions:The model with a single attachment and 1.2° of aligner activation was the most efficient, followed by the three attachment model with the same degree of activation. Aligner activation should not exceed 1.2° to achieve better control of movement and reasonable stress in periodontal structures. 相似文献
99.
Deregibus Andrea Tallone Luca Rossini Gabriele Parrini Simone Piancino Mariagrazia Castroflorio Tommaso 《Journal of orofacial orthopedics》2020,81(4):229-238
Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie - The purpose of this study was to evaluate the arch form changes in class II Caucasian patients treated with... 相似文献
100.
Angela De Rose Gabriele Mikolasch Mathias Kamp Achim Kraft Mathias Nowottnick 《RSC advances》2020,10(66):40215
Within this work, we demonstrate that an easy soldering process in combination with wet chemical coating is suitable to realize a strong and reliable solder interconnection of Al substrates, even at short soldering times <5 s in ambient air. The microstructure of solder joints on wet chemically treated aluminum foils is investigated. A single and double zincate pre-treatment are compared to activate the Al surface, followed by electroless Ni plating. The quality of the solderable Ni surface is characterized by contact angle measurements, yielding good wettability (<60°), which is also achieved after isothermally heating (250 °C) the Ni-coated Al foils for 100 min. The microstructure of the Sn62Pb36Ag2 solder joints is investigated by SEM and EDX of cross sections, directly after soldering as well as after isothermal aging at 85 °C. Under the used soldering conditions, with a soldering temperature at about 280 °C, diffusion zones <500 nm were identified. Nonetheless, high peel forces after soldering >5 N mm−1 show stable values under aging conditions of 85 °C for 1000 hours. This could be correlated to a mixed fracture pattern, promoting the high adhesion due to the absence of a dominant failure mechanism.High mechanical reliability of tin-based solder joints processed by joining copper and nickel-coated aluminium with short soldering times in ambient air. 相似文献