全文获取类型
收费全文 | 691篇 |
免费 | 42篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 14篇 |
妇产科学 | 3篇 |
基础医学 | 32篇 |
口腔科学 | 36篇 |
临床医学 | 91篇 |
内科学 | 88篇 |
皮肤病学 | 27篇 |
神经病学 | 20篇 |
特种医学 | 20篇 |
外科学 | 157篇 |
综合类 | 108篇 |
预防医学 | 47篇 |
眼科学 | 9篇 |
药学 | 71篇 |
1篇 | |
中国医学 | 9篇 |
肿瘤学 | 7篇 |
出版年
2024年 | 1篇 |
2023年 | 18篇 |
2022年 | 17篇 |
2021年 | 22篇 |
2020年 | 38篇 |
2019年 | 25篇 |
2018年 | 16篇 |
2017年 | 14篇 |
2016年 | 8篇 |
2015年 | 13篇 |
2014年 | 24篇 |
2013年 | 56篇 |
2012年 | 21篇 |
2011年 | 23篇 |
2010年 | 32篇 |
2009年 | 31篇 |
2008年 | 25篇 |
2007年 | 29篇 |
2006年 | 18篇 |
2005年 | 24篇 |
2004年 | 21篇 |
2003年 | 22篇 |
2002年 | 23篇 |
2001年 | 11篇 |
2000年 | 23篇 |
1999年 | 13篇 |
1998年 | 11篇 |
1997年 | 11篇 |
1996年 | 10篇 |
1995年 | 25篇 |
1994年 | 20篇 |
1993年 | 17篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 12篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有750条查询结果,搜索用时 15 毫秒
1.
目的 分析聚乙二醇干扰素(PEg-IFNα-2a、PEg-IFNα-2b)治疗低水平HBsAg慢性乙型病毒性肝炎(CHB)的临床疗效。方法 采用回顾性研究,选取2017年1月1日—2019年1月1日于北京大学深圳医院感染性疾病科门诊就诊,HBsAg<500 IU/mL且开始使用聚乙二醇干扰素治疗的慢性乙型病毒性肝炎患者,分析在治疗第24周、第48周HBsAg清除率及相关疗效影响因素。结果 共纳入88例患者,在0~48周达到HBsAg清除有45例,其中应答组与未应答组性别、HBsAg基线水平差异有统计学意义(P<0.05);达到HBsAg清除的45例中,24例使用PEg-IFNα-2a治疗,21例使用PEg-IFNα-2b治疗,两组HBsAg清除率差异无统计学意义(P=0.195);治疗第24周时新增HBsAg清除患者25例,经多因素分析,基线HBsAg水平差异有统计学意义(OR=0.991,95%CI=0.983~1.000,P=0.042);治疗第48周时新增HBsAg清除患者10例,经多因素分析,第24周HBsAg下降率有统计学意义(OR=1.063,95%CI=1.077~1.123,P=0.027)。结论 聚乙二醇干扰素治疗HBsAg<500 IU/mL慢性乙型病毒性肝炎患者HBsAg 清除率明显高于基线水平高者;PEg-IFNα-2a、PEg-IFNα-2b疗效无差异。治疗过程中第24周HBsAg下降幅度可预测治疗48周时HBsAg清除率。 相似文献
2.
目的观察高频喷射通气对老年无痛苦纤维支气管镜检患者血气结果的影响。方法 102例患者随机均分为两组,观察组喷射频率60次/min,对照组喷射频率25次/min。分别在麻醉前及喷射通气10 min时采股动脉血行血气分析,记录呛咳、呼吸抑制、体动反应和二氧化碳CO2蓄积例数。结果麻醉前及喷射通气10 min后动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)和动脉血氧饱和度(SaO2)组间比较,差异均无统计学意义(P0.05)。每组喷射通气10 min后,PaO2、PaCO2和SaO2均明显升高,与麻醉前比较,差异有统计学意义(P 0.05)。观察组有4例、对照组有7例发生CO2蓄积,但PaCO265 mmHg,组间比较,差异无统计学意义(P0.05)。结论高频喷射通气可以为老年患者纤维支气管镜检查麻醉提供可靠的氧供,但不一定能阻止呼吸抑制等因素引起的CO2蓄积,应引起足够的临床重视。 相似文献
3.
Eri Minamino-Muta Takao Kato Takeshi Morimoto Tomohiko Taniguchi Chisato Izumi Kenji Nakatsuma Moriaki Inoko Shinichi Shirai Norio Kanamori Koichiro Murata Takeshi Kitai Yuichi Kawase Makoto Miyake Hirokazu Mitsuoka Yutaka Hirano Tomoki Sasa Kazuya Nagao Tsukasa Inada Takeshi Kimura 《JACC: Cardiovascular Interventions》2019,12(24):2499-2511
ObjectivesThe aim of this study was to investigate the prognostic impact of the decline in left ventricular ejection fraction (LVEF) at 1-year follow-up in patients with severe aortic stenosis (AS) managed conservatively.BackgroundNo previous study has explored the association between LVEF decline during follow-up and clinical outcomes in patients with severe AS.MethodsAmong 3,815 patients with severe AS enrolled in the multicenter CURRENT AS (Contemporary Outcomes After Surgery and Medical Treatment in Patients With Severe Aortic Stenosis) registry in Japan, 839 conservatively managed patients who underwent echocardiography at 1-year follow-up were analyzed. The primary outcome measure was a composite of AS-related deaths and hospitalization for heart failure.ResultsThere were 91 patients (10.8%) with >10% declines in LVEF and 748 patients (89.2%) without declines. Left ventricular dimensions and the prevalence of valve regurgitation and atrial fibrillation or flutter significantly increased in the group with declines in LVEF. The cumulative 3-year incidence of the primary outcome measure was significantly higher in the group with declines in LVEF than in the group with no decline (39.5% vs. 26.5%; p < 0.001). After adjusting for confounders, the excess risk of decline in LVEF over no decline for the primary outcome measure remained significant (hazard ratio: 1.98; 95% confidence interval: 1.29 to 3.06). When stratified by LVEF at index echocardiography (≥70%, 60% to 69%, and <60%), the risk of decline in LVEF on the primary outcome was consistently seen in all the subgroups, without any interaction (p = 0.77).ConclusionsPatients with severe AS with >10% declines in LVEF at 1 year after diagnosis had worse AS-related clinical outcomes than those without declines in LVEF under conservative management. (Contemporary Outcomes After Surgery and Medical Treatment in Patients With Severe Aortic Stenosis Registry; UMIN000012140) 相似文献
4.
5.
目的 评价魏氏鼻咽通气道在鼾症患者气管插管前经声门上喷射通气应用的安全性与可行性。方法 选择2019年1~11月在解放军第九一○医院拟行全麻的鼾症患者50例,采用随机数字表法分为魏氏声门上喷射通气组(W组)与面罩通气组(M组),每组25例。麻醉诱导后,W组经鼻插入魏氏鼻咽通道行声门上喷射通气,M组双手扣面罩通气。5 min后气管插管,记录在给氧去氮5 min自主呼吸时(T0)、麻醉诱导后无自主呼吸1 min(T1)、2 min(T2)、3 min(T3)、4 min(T4)和5 min后插管后即刻(T5)用超声测量的膈肌波动振幅均值、呼末二氧化碳分压(PETCO2),动脉血气[动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)、血氧饱和度(SpO2)];记录过程中SpO2<90%、平均动脉压(MAP)和心率(HR)波动≥术前20%的发生情况,并记录通气相关并发症的发生情况。结果 两组患者膈肌呼吸运动振幅、PaO2、PaCO2和PETCO2指标在T0时差异无统计学意义(P>0.05);W组患者膈肌呼吸运动振幅和PaO2较高,W组患者PaCO2和PETCO2较低,差异有统计学意义(P<0.05);与T0时比较,两组患者T1~T5时膈肌呼吸运动振幅和PaO2升高,PaCO2和PETCO2降低,差异有统计学意义(P<0.05);分组与时间对各指标的差异存在交互作用,差异有统计学意义(P<0.05)。W组患者下颌角皮肤红肿淤青、胃肠胀气的发生率低于M组,差异有统计学意义(P<0.05)。结论 魏氏声门上喷射鼻咽通气道可为鼾症伴有肥胖患者气管插管提供满意的声门上通气效果,且安全性较好。 相似文献
6.
7.
Feifei Zhang Weikai Li Huiru Li Shaobing Gao John A. Sweeney Zhiyun Jia Qiyong Gong 《Human brain mapping》2020,41(9):2281-2291
Jet lag is commonly experienced when travelers cross multiple time zones, leaving the wake–sleep cycle and intrinsic biological “clocks” out of synchrony with the current environment. The effect of jet lag on intrinsic cortical function remains unclear. Twenty‐two healthy individuals experiencing west‐to‐east jet lag flight were recruited. Brain structural and functional magnetic resonance studies, as well as psychological and neurohormonal tests, were carried out when participants returned from travel over six time zones and 50 days later when their jet lag symptoms had resolved. During jet lag, the functional brain network exhibited a small‐world topology that was shifted toward regularity. Alterations during jet lag relative to recovery included decreased basal ganglia‐thalamocortical network connections and increased functional connectivity between the medial temporal lobe subsystem and medial visual cortex. The lower melatonin and higher thyroid hormone levels during jet lag showed the same trend as brain activity in the right lingual gyrus. Although there was no significant difference between cortisol measurements during and after jet lag, cortisol levels were associated with temporal lobe activity in the jet lag condition. Brain and neuroendocrine changes during jet lag were related to jet lag symptoms. Further prospective studies are needed to explore the time course over which jet lag acts on the human brain. 相似文献
8.
A Compressible Conserved Discrete Unified Gas-Kinetic Scheme with Unstructured Discrete Velocity Space for Multi-Scale Jet Flow Expanding into Vacuum Environment 下载免费PDF全文
Jianfeng Chen Sha Liu Yong Wang & Chengwen Zhong 《Communications In Computational Physics》2020,28(4):1502-1535
The mechanism of jet flow expanding into vacuum environment (or extremely low density environment) is important for the propulsion unit of micro-electro-mechanical systems (MEMS), the thruster of spacecraft, the attitude control system of
satellite, etc.. Since its flow field is often composed of local continuum region and local rarefied region, the jet flow into vacuum has noteworthy multi-scale transportation
behaviors. Therefore, the numerical study of such flows needs the multi-scale schemes
which are valid for both continuum and rarefied flows. In the past few years, a series
of unified methods for whole flow regime (from continuum regime to rarefied regime)
have been developed from the perspective of the direct modeling, and have been verified by sufficient test cases. In this paper, the compressible conserved discrete unified
gas-kinetic scheme is further developed and is utilized for predicting the jet flows into
vacuum environment. In order to cover the working conditions of both aerospace and
MEMS applications, the jet flows with a wide range of inlet Knudsen (Kn) numbers
(from 1E-4 to 100) are considered. The evolution of flow field during the entire startup
and shutdown process with Kn number 100 is predicted by the present method, and
it matches well with the result of analytical collisionless Boltzmann equation. For Kn
numbers from 1E-4 to 10, the flow field properties such as density, momentum, and
pressure are investigated, and the results are provided in details, since the published
results are not sufficient at the present stage. The extent and intensity of the jet flow
influence are especially investigated, because they are strongly related to the plume
contamination and momentum impact on objects facing the jet, such as the solar paddles which face the attitude control thruster during the docking process. 相似文献
9.
《Anaesthesia and Intensive Care Medicine》2020,21(4):205-208
Anaesthesia for endoscopic airway surgery involves unique challenges. The anaesthetist and surgeon are working in close anatomical proximity and the concept of shared airway is never more relevant. Understanding the planned procedure and the needs of the surgeon for access to the surgical field will enable the provision of anaesthesia and airway management using a variety of techniques. Planning for safe induction, maintenance and emergence of anaesthesia will also be guided by the specific pathology and patient characteristics and requires effective communication between the surgeon and anaesthetist. 相似文献