全文获取类型
收费全文 | 28552篇 |
免费 | 2182篇 |
国内免费 | 545篇 |
专业分类
耳鼻咽喉 | 252篇 |
儿科学 | 969篇 |
妇产科学 | 507篇 |
基础医学 | 1729篇 |
口腔科学 | 614篇 |
临床医学 | 5934篇 |
内科学 | 4332篇 |
皮肤病学 | 567篇 |
神经病学 | 982篇 |
特种医学 | 670篇 |
外国民族医学 | 5篇 |
外科学 | 3318篇 |
综合类 | 4191篇 |
预防医学 | 2022篇 |
眼科学 | 165篇 |
药学 | 2818篇 |
14篇 | |
中国医学 | 1664篇 |
肿瘤学 | 526篇 |
出版年
2024年 | 62篇 |
2023年 | 621篇 |
2022年 | 876篇 |
2021年 | 1443篇 |
2020年 | 1234篇 |
2019年 | 1126篇 |
2018年 | 1097篇 |
2017年 | 1136篇 |
2016年 | 1096篇 |
2015年 | 1023篇 |
2014年 | 2279篇 |
2013年 | 2453篇 |
2012年 | 1865篇 |
2011年 | 1883篇 |
2010年 | 1567篇 |
2009年 | 1370篇 |
2008年 | 1288篇 |
2007年 | 1321篇 |
2006年 | 1170篇 |
2005年 | 1042篇 |
2004年 | 815篇 |
2003年 | 635篇 |
2002年 | 529篇 |
2001年 | 417篇 |
2000年 | 351篇 |
1999年 | 311篇 |
1998年 | 268篇 |
1997年 | 231篇 |
1996年 | 217篇 |
1995年 | 182篇 |
1994年 | 172篇 |
1993年 | 114篇 |
1992年 | 122篇 |
1991年 | 102篇 |
1990年 | 118篇 |
1989年 | 114篇 |
1988年 | 72篇 |
1987年 | 74篇 |
1986年 | 55篇 |
1985年 | 69篇 |
1984年 | 58篇 |
1983年 | 31篇 |
1982年 | 29篇 |
1981年 | 26篇 |
1980年 | 30篇 |
1979年 | 20篇 |
1978年 | 19篇 |
1975年 | 19篇 |
1973年 | 31篇 |
1971年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
71.
应用无死腔气管插管提高正常和急性肺损伤兔的机械通气效率 总被引:2,自引:1,他引:1
目的:观察无死腔气管插管能否提高急性呼吸衰竭常规机械通气的效果。方法:应用一种新型无死腔气管插管和普通聚氯乙烯气管插管对正常和急性肺损伤兔进行常规通气,对两种气管插管的肺气体交换和气道内气体动力学及血流动力学变化进行比较。无死腔气管插管用2根Potex气管插管远端3cm处纵切后对粘而成。5只新西兰成年兔,麻醉下气管切开,在持续应用潘龙阻断自主呼吸条件下,随机用新型气管插管和普通气管插管Servo900C进行机械通气,每次持续30分钟,测定并记录动脉血压、气道压力、血流动力学参数和呼气末CO2浓度。结果:在正常肺和急性肺损伤条件下,新型气管插管可使所有动物的PaCO2和生理死腔/潮气量(VD/VT)下降,PaCO2分别下降1.40±0.20kPa(1kPa=7.5mmHg)和1.60±0.30kPa(P<0.01),VD/VT分别下降0.13±0.02和0.15±0.04(P<0.01);PaO2、气道压力和血流动力学无显著变化。结论:无死腔气管插管可明显提高常规机械通气效率。 相似文献
72.
The systolic hump in the aortic blood pressure wave is defined as the aorticresistance component proportional to the aortic
blood flow superimposed on the windkessel component. An electrical analogue comprising a series resistance (aortic resistance)
plus a resistance (peripheral resistance) and capacitance (aortic compliance) in parallel (i.e. windkessel component) is used
for analysis. Curve fitting using the leastsquares method is performed on calculated and measured blood pressure waves from
dogs under haemodynamical conditions induced by infusion of three drugs (noradrenaline, isoproterenol and acetylcholine).
The curve fitting RMS (root mean square) errors are <3% for blood pressure waves and <30% for blood flow waves, with good
agreement between measured and calculated blood flow waveforms. Infusion of noradrenaline and acetylcholine is found to induce
a significant decrease and increase in the aortic resistance, respectively. Although only a small fraction of the blood pressure
wave, the systolic hump has a marked effect on the systolic pressure waveform. 相似文献
73.
Intermittent positive pressure ventilation by nasal mask: Technique and applications 总被引:1,自引:0,他引:1
Intermittent positive pressure ventilation delivered non-invasively through a well-fitting nasal mask has been used to control nocturnal hypoventilation in three patients with severe, combined cardio-respiratory and skeletal disease. The advantages of this approach to domiciliary ventilation are described and the requirements of the ventilator are defined. 相似文献
74.
目的:探讨气管切开与呼吸机机械通气抢救重度有机磷农药中毒(AOPP)致呼吸肌麻痹的疗效。方法:对6例重度AOPP致呼吸肌麻痹患者在综合治疗基础上,及时予气管切开,并使用全能呼吸机机械通气。结果:治愈5例,死亡1例。抢救成功率达83.3%。结论:对重度AOPP患者及时行气管切开,并使用全能呼吸机机械通气,抢救效果良好。 相似文献
75.
复方18甲基炔诺酮/雌二醇透皮控释传递系统(LNG/E_2 TCDS)能同时恒速释放低剂量的LNG和E_2,在1周内维持一个平稳而有效的LNG血药浓度。药动学与药效学研究证明,该系统释放的LNG能达到血清LNG目标水平,产生有效的排卵抑制(6/6)。LNG/E_2 TCDS可望发展成为一种安全、有效、非侵入性的新型生育调节避孕制剂。 相似文献
76.
熵代表无序的水平,作者使用通气的熵变(ECV)指示肺通气的不均匀性,ECV定义为当前泡潮气量趋近于零时每摩尔被吸入气体从不均匀通气到均匀通气的熵变的极限。本文从熵的基本公式民地出ECV的计算方程。用几个数学模型肺将ECV同其他7个洗出指标进行了比较。8个指标中,只有ECV仅取决于通气分布,其他7个指标不仅取决于通气分布,还同潮气量和死腔的大小有关。这影响了它们评价肺通气不均匀性的效果,ECV的另一 相似文献
77.
Sintov Amnon Scott William A. Gallagher Kim P. Levy Robert J. 《Pharmaceutical research》1990,7(1):28-33
Epicardial antiarrhythmic drug administration was studied as a therapeutic approach for experimental ventricular tachycardia (VT) in an open-chest dog model. Lidocaine-polyurethane matrices (28%, w/w) were formulated as a model system. Matrices were placed on the left ventricular epicardium in each of 23 anesthetized open-chest dogs with ouabain-induced VT, to evaluate effectiveness in restoring sinus rhythm. Conversion occurred in all animals treated with matrices containing 300 mg or more of lidocaine after 1.5 to 7.0 min. The matrix lidocaine content correlated linearly with the time required for conversion to sinus rhythm (r = 0.75, P = 0.0002); irrespective of matrix size the myocardial/plasma lidocaine ratio was 20.1 ± 4.2 (mean ± SD) at the time of conversion. In a separate series of five dogs without ventricular tachycardia, systolic wall thickening measured with sonomicrometers after 5 min of controlled-release lidocaine administration (500- to 1000-mg matrix lidocaine content, 7.48 ± 3.49-mg/kg dose) was only minimally diminished (–14.1%) and this effect was observed only at the site of matrix placement on the anterior-apical epicardium. In contrast, intracoronary injection of 0.3 or 1.0 mg/kg of lidocaine-HCl resulted in complete elimination of wall thickening or replacement by systolic thinning. Thus epicardial administration of lidocaine from polyurethane matrices was an effective means of treating ouabain-induced ventricular tachycardia. Regional myocardial function in the vicinity of the matrices was modified to a very limited degree, supporting the view that the matrices can be used safely, without serious risk to ventricular contractile performance. 相似文献
78.
C. J. Bowden W. D. Figg N. A. Dawson O. Sartor R. J. Bitton M. S. Weinberger Donna Headlee Eddie Reed C. E. Myers M. R. Cooper 《Cancer chemotherapy and pharmacology》1996,39(1-2):1-8
Introduction: Suramin is a synthetic polysulfonated naphthylurea which has been used for the treatment of African trypanosomiasis and onchocerciasis,
but since the mid-1980s has received attention as a possible antiretroviral and antineoplastic agent. Objective: This clinical trial of suramin was undertaken as a phase I/II study in patients with hormone-refractory prostate cancer,
with the hypothesis that the intensity of therapy with suramin could be increased significantly if measures were undertaken
to maintain the plasma concentrations of the drug under 300 μg/ml. Methods: We report the clinical results of this trial, wherein patients were treated at three different targeted plasma suramin concentrations
(275, 215 and 175 μg/ml) for varying periods of time (2, 4 or 8 weeks), with delivery of the drug by continuous intravenous
infusion. Results: The major toxicity observed in this trial was neurologic, consisting of a motor and sensory peripheral neuropathy that resulted
in both paresis and paralysis of the limbs. Nearly all of this severe (CTEP grade III, IV) neurologic toxicity was observed
in the patients treated at a plasma suramin concentration of 275 μg/ml for 4 or more weeks. A single patient treated at 215 μg/ml
for 8 weeks developed moderate (CTEP grade III) proximal lower extremity weakness, and no patient treated at 175 μg/ml developed
this toxicity. The second most common toxicity observed was infection of the central venous catheter. The overall response
rate for all of the evaluable patients was 17% (13 of 75 patients). In addition, prostate-specific antigen (PSA)-defined responses
were observed in six patients receiving therapy at 175 μg/ml, but these responses were confounded by cessation of therapy
with flutamide during suramin treatment. Conclusions: In summary, although plasma suramin concentrations were maintained below 300 μg/ml, neurologic toxicity nonetheless occurred
with high frequency in patients treated at 275 μg/ml for 4 or more weeks. Therapy at 215 and 175 μg/ml was in general well
tolerated, but central venous catheter-related infection, as well as the inconvenience and expense of continuous infusional
therapy, make this method of drug delivery impractical. Only moderate antitumor activity was observed during this trial, but
it is possible that both continuation of flutamide and flutamide withdrawal during suramin therapy confounded the assessment
of suramin’s activity in hormone-refractory prostate cancer.
Received: 9 June 1995/Accepted: 18 March 1996 相似文献
79.
机械通气并发气胸的诊断及处理 总被引:4,自引:0,他引:4
气胸是机械通气常见的并发症,在成人呼吸窘迫综合征(ARDS)及慢性阻塞性肺部疾病(COPD)中发生率较高,分别是29.4%和27.8%,且多为张力性气胸。预防气胸发生的简便方法是在保证有效通气量的前提下,适当降低潮气量。机械通气过程中,患者出现血氧饱和度下降、气道压力增高、患侧呼吸音降低、心率加快及呼吸困难等临床症状均高度提示并发气胸,试穿患侧胸腔有大量气体即可诊断。安置该侧胸腔闭式引流是有效的治疗方法。 相似文献
80.
G Dimitriou A Greenough B Laubscher N Yamaguchi 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(12):1256-1260
Failure of patient-triggered ventilation in very immature infants may be due to the use of inappropriate triggering systems. Two types of airflow trigger were therefore compared consecutively to an airway pressure (SLE) triggering system. Each comparison was made in 10 infants, ≤28 weeks of gestation. Comparison was made of the delivered volume, trigger performance and blood gases using each system for 1 h. Both comparisons showed that the airflow triggering systems performed better: one (Draeger Babylog 8000) had a higher sensitivity ( p < 0:01) and the other (Bird VIP airflow trigger), in which inflation was terminated by sensing a reduction in inspiratory flow, had a lower degree of asynchrony ( p < 0:01) and a tendency to deliver higher volumes. These results suggest that triggering systems sensing airflow changes may be superior to those sensing airway pressure changes in very immature infants. The use of a mechanism to synchronize the termination of inflation to the end of the patient's inspiration may offer further advantages. 相似文献