首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   61134篇
  免费   4922篇
  国内免费   2926篇
耳鼻咽喉   1701篇
儿科学   550篇
妇产科学   535篇
基础医学   7581篇
口腔科学   1807篇
临床医学   5715篇
内科学   4429篇
皮肤病学   351篇
神经病学   8925篇
特种医学   1537篇
外国民族医学   8篇
外科学   11915篇
综合类   10469篇
现状与发展   3篇
预防医学   1495篇
眼科学   4282篇
药学   4439篇
  63篇
中国医学   1448篇
肿瘤学   1729篇
  2024年   122篇
  2023年   928篇
  2022年   1536篇
  2021年   2240篇
  2020年   2225篇
  2019年   1967篇
  2018年   1909篇
  2017年   2245篇
  2016年   2291篇
  2015年   2296篇
  2014年   3878篇
  2013年   3739篇
  2012年   3320篇
  2011年   3631篇
  2010年   3157篇
  2009年   2869篇
  2008年   3082篇
  2007年   3065篇
  2006年   2792篇
  2005年   2446篇
  2004年   2114篇
  2003年   1847篇
  2002年   1622篇
  2001年   1436篇
  2000年   1176篇
  1999年   1084篇
  1998年   1043篇
  1997年   958篇
  1996年   753篇
  1995年   725篇
  1994年   587篇
  1993年   591篇
  1992年   578篇
  1991年   533篇
  1990年   495篇
  1989年   405篇
  1988年   374篇
  1987年   357篇
  1986年   322篇
  1985年   427篇
  1984年   353篇
  1983年   247篇
  1982年   263篇
  1981年   232篇
  1980年   212篇
  1979年   139篇
  1978年   94篇
  1977年   89篇
  1976年   65篇
  1975年   41篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Gold nanoparticles (Au NPs) hold great promise in food, industrial and biomedical applications due to their unique physicochemical properties. However, influences of the gastrointestinal tract (GIT), a likely route for Au NPs administration, on the physicochemical properties of Au NPs has been rarely evaluated. Here, we investigated the influence of GIT fluids on the physicochemical properties of Au NPs (5, 50, and 100?nm) and their implications on intestinal epithelial permeability in vitro. Au NPs aggregated in fasted gastric fluids and generated hydroxyl radicals in the presence of H2O2. Cell studies showed that GIT fluids incubation of Au NPs affected the cellular uptake of Au NPs but did not induce cytotoxicity or disturb the intestinal epithelial permeability.  相似文献   
4.
5.
IntroductionThere is still no consensus in the literature as to the best acoustic stimulus for capturing vestibular evoked myogenic potential (VEMP). Low-frequency tone bursts are generally more effective than high-frequency, but recent studies still use clicks. Reproducibility is an important analytical parameter to observe the reliability of responses.ObjectiveTo determine the reproducibility of p13 and n23 latency and amplitude of the VEMP for stimuli with different tone-burst frequencies, and to define the best test frequency.MethodsCross-sectional cohort study. VEMP was captured in 156 ears, on the sternocleidomastoid muscle, using 100 tone-burst stimuli at frequencies of 250, 500, 1000, and 2000 Hz, and sound intensity of 95 dB nHL. Responses were replicated, that is, recorded three times on each side.ResultsNo significant difference was observed for p13 and n23 latencies of the VEMP, captured at three moments with tone-burst stimuli at 250, 500, and 1000 Hz. Only the frequency of 2000 Hz showed a difference between captures of this potential (p < 0.001). p13 and n23 amplitude analysis was also similar in the test–retest for all frequencies analyzed.Conclusionp13 and n23 latencies and amplitudes of VEMP for tone-burst stimuli at frequencies of 250, 500, and 1000 Hz are reproducible.  相似文献   
6.
7.
8.
9.
目的 探讨快速康复外科 (FTS)理念在经后颅窝乙状窦后入路三叉神经微血管减压术围术期患者护理中的应用效果。方法 选择2018年1月~2019年1月我院收治并行经后颅窝乙状窦后入路三叉神经微血管减压患者100例,随机分成观察组和对照组,每组50例。对照组应用常规方法进行围术期护理,观察组应用FTS理念进行围术期护理。比较两组焦虑情况、术后并发症发生率、平均住院日及平均住院费用。结果 观察组轻度焦虑多于对照组,中、重度焦虑少于对照组(P<0.05);观察组术后并发症发生率低于对照组[恶心呕吐(4.00% vs 16.00%)、尿路感染(4.00% vs 18.00%)、颅内感染(0 vs 8.00%)、颅内血肿(2.00% vs 14.00%)和术后应激性疼痛(16.00% vs 34.00%)],差异有统计学意义(P<0.05);观察组平均住院日和平均住院费用均低于对照组[(9.13±1.14)d vs(12.44±0.89)d];[(2.15±0.66)万元 vs (3.05±0.61)万元],差异有统计学意义(P<0.05)。结论 应用FTS理念能缓解经后颅窝乙状窦后入路三叉神经微血管减压术患者术前紧张恐惧的心理,减少术后并发症,缩短患者住院日,降低住院费用,护理效果较好。  相似文献   
10.
《Dental materials》2020,36(1):119-134
ObjectiveThe aim of this systematic review and meta-analysis was to evaluate the effect of surface conditioning methods on the bond strength of industrial indirect composite blocks (ICs).MethodsBased on the PICOS strategy, the Medline via PubMed, Embase and Web of Science (ISI – Web of Knowledge) electronic databases were searched for peer-reviewed articles in both English and Chinese, with no publication year limit. In vitro studies evaluating the effects of surface conditioning on the bond strength of ICs were selected. The meta-analysis was conducted to calculate the mean difference between surface-conditioned ICs and unconditioned controls. Subgroup analysis was performed to evaluate the different surface conditioning methods, separately for polymer-infiltrated ceramic network (PICN) material and the ICs with dispersed fillers (ICDFs). Meta-analyses were performed with a random-effects model at a significance level of 0.05.Results and SignificanceFrom 802 relevant studies, 25 were selected for full-text analysis. Nineteen studies were eligible for inclusion in this systematic review, whereas 9 studies were included in the meta-analysis. A manual search of the principal periodicals specific to the area resulted in no additional articles. The meta-analysis indicated a significant difference in bond strength between the surface-conditioned ICs and controls under both non-aged and aged conditions. The combination of mechanical and chemical conditioning yielded the highest bond strength of ICs. This meta-analysis suggests that chemical etching followed by a universal primer and alumina air abrasion followed by a silane coupling agent could be considered the best strategy for optimizing the bond strength of PICN materials and ICDFs under aged conditions, respectively.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号