全文获取类型
收费全文 | 13340篇 |
免费 | 1093篇 |
国内免费 | 120篇 |
专业分类
耳鼻咽喉 | 78篇 |
儿科学 | 187篇 |
妇产科学 | 99篇 |
基础医学 | 1247篇 |
口腔科学 | 120篇 |
临床医学 | 2577篇 |
内科学 | 956篇 |
皮肤病学 | 57篇 |
神经病学 | 703篇 |
特种医学 | 475篇 |
外科学 | 1302篇 |
综合类 | 1845篇 |
预防医学 | 2923篇 |
眼科学 | 60篇 |
药学 | 1264篇 |
3篇 | |
中国医学 | 463篇 |
肿瘤学 | 194篇 |
出版年
2023年 | 144篇 |
2022年 | 316篇 |
2021年 | 443篇 |
2020年 | 380篇 |
2019年 | 337篇 |
2018年 | 343篇 |
2017年 | 343篇 |
2016年 | 342篇 |
2015年 | 331篇 |
2014年 | 851篇 |
2013年 | 813篇 |
2012年 | 853篇 |
2011年 | 984篇 |
2010年 | 783篇 |
2009年 | 895篇 |
2008年 | 964篇 |
2007年 | 690篇 |
2006年 | 587篇 |
2005年 | 463篇 |
2004年 | 371篇 |
2003年 | 315篇 |
2002年 | 237篇 |
2001年 | 408篇 |
2000年 | 324篇 |
1999年 | 251篇 |
1998年 | 107篇 |
1997年 | 110篇 |
1996年 | 123篇 |
1995年 | 202篇 |
1994年 | 146篇 |
1993年 | 129篇 |
1992年 | 120篇 |
1991年 | 128篇 |
1990年 | 98篇 |
1989年 | 79篇 |
1988年 | 27篇 |
1987年 | 20篇 |
1986年 | 26篇 |
1985年 | 55篇 |
1984年 | 64篇 |
1983年 | 36篇 |
1982年 | 29篇 |
1981年 | 24篇 |
1980年 | 32篇 |
1979年 | 43篇 |
1978年 | 29篇 |
1977年 | 34篇 |
1976年 | 18篇 |
1975年 | 23篇 |
1973年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
背景 感染性休克患者存在肾脏血液灌注异常,严重时可诱发急性肾损伤(AKI),严重威胁患者生命安全;彩色多普勒超声(CDU)可用于评估肾脏血流变化,但有关其在感染性休克患者AKI评估中价值的研究较少。目的 通过CDU评价感染性休克患者AKI的发生情况及其血流动力学改变。方法 选取2019年6月至2021年7月徐州市中心医院收治的105例确诊为感染性休克的患者并纳入感染组,选取同期健康体检者58例并纳入对照组,收集受试者一般资料。采用CDU检查受试者肾脏血流动力学指标[肾动脉管腔内径(D)、收缩期血流峰值速度(Vs)、舒张末期血流速度(Vd)、阻力指数(RI)、搏动指数(PI)],比较感染组与对照组的一般资料及肾脏血流动力学指标。根据感染组患者入院72 h内发生AKI与否将其分为AKI组及非AKI组,比较AKI组与非AKI组肾脏血流动力学指标。应用受试者工作特征(ROC)曲线分析肾脏血流动力学指标对感染性休克患者发生AKI的预测价值。应用单因素分析及多因素Logistic回归分析探讨感染性休克患者发生AKI的影响因素。以AKI由轻到重的程度将患者分为AKIⅠ组、AKIⅡ组、AKIⅢ组,比较... 相似文献
82.
背景 小儿遗尿症是儿科常见病之一,有效的小儿遗尿症诊疗指南有助于症状的规范化控制和缓解,而制定高质量的临床实践指南是提高小儿遗尿症诊疗水平的重要方式。目的 基于AGREEⅡ和RIGHT工具,评价2010年以来国内外发布的小儿遗尿症指南和专家共识的质量,以期为临床实践及后续指南的制订提供参考。方法 检索中国知网、万方数据知识服务平台、维普网、中国生物医学文献数据库和PubMed(补充检索医脉通、世界卫生组织以及英国国家临床示范研究所等数据库)2010-01-01至2022-01-31公开发表的小儿遗尿症相关的诊疗指南和专家共识。采用AGREEⅡ和RIGHT工具评价纳入文献的方法学和报告质量。根据AGREE Ⅱ工具评价结果,将各指南/共识推荐等级评定为“推荐(A级)”“更新后推荐(B级)”和“不推荐(C级)”。使用组内相关系数(ICC)进行一致性评价。结果 纳入8部指南和5部专家共识。共形成推荐意见185条,其中44条为诊断评估方面的意见,140条为治疗方面的推荐意见,1条为随访推荐意见。AGREEⅡ工具评价结果显示,范围和目的、参与人员、严谨性、清晰性、应用性和独立性6个领域的总得分(报... 相似文献
83.
Janet L. Stringer Faruk Erden 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1990,105(3):391-401
Using a reverberatory epilepiform discharge of hippocampal-parahippocampal circuits termed maximal dentate activation, this study investigated whether the local release of nitric oxide within these circuits functions as an antiepileptic agent. Two nitric oxide synthase inhibitors (l-nitro-arginine methyl ester and 7-nitro-indazole) and a guanylate cyclase inhibitor (methylene blue) were tested, and none had a significant effect on the time to onset or duration of maximal dentate activation. A membrane-permeable analogue of cyclic guanosine monophosphate (cGMP), 8-bromo-cGMP, caused an increase in the time to onset and a decrease in the duration of maximal dentate activation. The number of neurons expressing NADPH diaphorase activity (a marker for nitric oxide synthase) was also examined after repeated elicitation of maximal dentate activation. After 18 seizures there was a significant, but transient, decrease in the number of hilar/subgranular neurons that were NADPH diaphorase-positive. The decrease was only seen at 1 h after the last seizure. There was no induction of NADPH diaphorase activity. These results are not consistent with the hypothesis that, in hippocampal-parahippocampal circuits in vivo, nitric oxide is released in response to neuronal activity and then acts to terminate the neuronal activity. 相似文献
84.
Twenty-two women were studied during laparoscopy with abdominal insufflation of carbon dioxide. A bain anaesthetic breathing circuit was used with a fresh gas flow (VFG) of 110 ml.min-1.kg-1, and controlled ventilation was applied with a minute ventilation (VE) of 175 ml.min-1.kg-1. Arterial blood gases were analysed at the end of the operation. Nineteen of the women (86 per cent) were found to have a PaCO2 within the range for normocapnia (i.e., 4.7-5.9 kPa (35-45 mmHg), two were hypocapnic with a PaCO2 of 4.4 and 4.5 kPa (33 and 34 mmHg) respectively and one was found to have a PaCO2 of 6.2 kPa (46.5 mmHg). It was concluded that the carbon dioxide absorbed from the abdomen during laparoscopy demands fresh gas flows that are higher than normally used in the Bain circuit if a PaCO2 within the normal range is to be obtained. A simultaneous increase in VFG and VE of about 45 per cent is sufficient to achieve normocapnia. 相似文献
85.
The case of a child whose tracheal tube became obstructed intraoperatively 30 minutes after intubation is reported. It appears
that this obstruction was related to the development of bubbles within the walls which expanded upon exposure to nitrous oxide
and diffusion of that gas into the bubbles. The authors want to point out the risk of gas diffusion into the walls of the
tube and the possibility that repeated sterilization may enhance the development of bubbles.
Les auteurs rapportent l’observation d’un enfant de sept mois dont la sonde tracheale s’est obstruée 30 minutes après l’intubation.
Cette obstruction était due à l’expansion de bulles incluses dans la paroi du tube après exposition au N2O et diffusion de celui-ci à l’interieur des bulles. Ils accusent également la stérilisation répétée de la sonde armée (contre
l’avis du constructeur) d’avoir favorisé le développement de ces inclusions bulleuses. 相似文献
86.
Drug interactions between the aminoglycosides (tobramycin and gentamicin) and atracurium and vecuronium were studied prospectively in 44 patients. Twenty-two patients had therapeutic serum levels of tobramycin or gentamicin and 22 served as controls. Onset time, clinical duration, and time to spontaneous recovery of T4/T1 ratio of 0.70 after atracurium or vecuronium injection were measured. No statistically significant differences were found in onset time, but clinical duration and time to recovery were significantly longer in patients receiving tobramycin or gentamicin and paralyzed with vecuronium than for controls (P less than 0.01 for clinical duration and P less than 0.0005 for recovery). The neuromuscular block produced by atracurium was not significantly influenced by the presence of therapeutic serum levels of tobramycin or gentamicin. We conclude that for patients treated with these antibiotics, atracurium may present some advantages over vecuronium when a prolonged block is not desired. 相似文献
87.
This is a retrospective study of the outcome of surgical procedures in patients who were Jehovah's Witnesses. Over a 75-month period, 58 Jehovah's Witness patients had 78 surgical procedures at the Vancouver General Hospital. Three patients had preexisting anaemia of less than 100 g.L-1 haemoglobin. Postoperative haemoglobin concentration decreased below 50 g.L-1 in three patients. One patient had a postoperative haemoglobin of 34 g.L-1 (haematocrit 10.1 per cent) and survived. One patient died from uncontrollable postoperative haemorrhage. Perioperative morbidity was not uncommon, including significant hypotension (eight cases), cardiac arrhythmias (six), myocardial ischaemia (three), excessive bleeding (four), postoperative nausea or syncope (four), and wound or urinary tract infection (four). 相似文献
88.
Andre P. Boezaart 《Journal canadien d'anesthésie》1989,36(6):697-700
A 23-year-old primigravid patient who received epidural analgesia for pain of labour presented with persistent, apparently irremediable, unilateral analgesia. Computerized axial tomo-epidurography demonstrated absence of circumferential spread due to lateral placement of the catheter. Transforaminal escape of contrast medium into the paravertebral area had occurred and anterior and posterior midline partitioning of the epidural space was obvious. All the usual measures to promote contralateral analgesia, except re-insertion of the catheter, had been tried without success. 相似文献
89.
J. L. Beal M. Freysz G. Berthelon P. D’Athis S. Briet M. Wilkening 《Journal canadien d'anesthésie》1989,36(3):278-282
This prospective and randomized study compared the consequences of two irrigating fluids, distilled water and glycine for
transurethral prostatectomy. Forty-nine consecutive unselected patients undergoing transurethral resection of the prostate
with spinal anaesthesia were investigated. The irrigating fluid was either distilled water (group A, 24 patients) or glycine
1.5 per cent (group B, 25 patients). The absorption of irrigating fluid was measured, all surgical events and any clinical
signs of TURP syndrome during and after surgery were recorded. Early signs of TURP syndrome were observed in one patient in
group A and in four in group B without further consequence. From all the biological variables, only plasma protein concentration,
haematocrit, free plasma haemoglobin and free bilirubin concentrations were found to have changed. Plasma protein concentration
and haematocrit decreased significantly during and after surgery in the two groups. Free plasma haemoglobin increased significantly
with time: a significantly higher concentration was observed in group A than group B. Free bilirubin concentration increased
with time in the two groups and was statistically greater in group A. With the two irrigating fluids, we observed a significant
amount of haemolysis and haemodilution without clinical consequences. A low irrigating fluid pressure, a short resection time,
and the use of spinal anaesthesia seems to us to be essential. Close observation of patients following transurethral prostatectomy
is needed but the choice of the irrigating fluid does not seem to be important.
Cette étude prospective et randomisée a comparé les conséquences de deux liquides d’irrigation, l’eau distillée et le glycocolle
au cours de la chirurgie prostatique par voie basse. Quarante-neuf patients consécutifs, non sélectionnés, bénéficiant d’une
résection transuréthrale de prostate sous rachianesthésie, sont étudiés. Le liquide d’irrigation est soil l’eau distillée
(groupe A, 24 patients), soit le glycocolle à 1.5 pour cent (groupe B, 25 patients). L’absorption des liquides d’irrigation,
les incidents chirurgicaux et les signes cliniques du syndrome de réabsorption sont systématiquement notés. Des signes caractéristiques
du syndrome de réabsorption sont observés dans un cas dans le groupe A et dans quatre cos dans le groupe B sans conséquence
ultérieure. Seuls la protidémie, l’hématocrite, l’hémoglobine plasmatique libre et la bilirubine libre changent significativement.
L’hémoglobine plasmatique libre augmente significativement dans les deux groupes, avec un taux plasmatique significativement
plus élevé dans le groupe A. Avec les deux liquides d’irrigation, on observe une hémolyse et une hémodilution sans conséquence
clinique. Un temps de résection court, un faible niveau de pression d’irrigation, l’utilisation de l’anesthésie rachidienne
nous semblent trés importants. Une surveillance clinique et biologique attentive pendant et après la résection transuréthrale
de prostate sont nécessaires; en revanche, le choix du liquide d’irrigation ne semble pas l’élément essentiel. 相似文献
90.
David J. Murray Robert B. Forbes Judith B. Dillman Larry T. Mahoney David L. Dull 《Journal canadien d'anesthésie》1989,36(3):295-300
In this study, two-dimensional and pulsed Doppler echocardiography were used to measure cardiovascular changes before and
after IV atropine in 31 infants and small children during halothane (n = 15) or isoflurane (n = 16) anaesthesia. Prior to
induction of anaesthesia heart rate (HR), mean blood pressure (MBP), and two0dimensional echocardiographic dimensions of the
left ventricle and pulmonary artery bloodflow velocity were measured by pulsed Doppler echocardiography. Cardiovascular measurements
were repeated while anaesthesia was maintained at 1.5 MAC halothane (n = 15) or isoflurane (n = 16). Atropine 0.02 mg·kg−1 IV was then administered and two minutes later, a third set of cardiovascular data was obtained. Heart rate decreased during
halothane anaesthesia but did not change significantly during isoflurane anaesthesia. Mean blood pressure, cardiac output
(CO) and stroke volume (SV) decreased similarly during 1.5 MAC halothane or isoflurane anaesthesia. Ejection fraction (EF)
decreased and left ventricular end-diastolic volume (LVEDV) increased significantly in bothgroups, but decreases in EF (32
± 5 percentvs18 ± 5 per cent) and increases in LVEDV (18 ± 7 per cent vs7 ± 5 per cent) were significantly greater during
halothane than during isoflurane anaesthesia. Following atropine, HR increased more in the patients maintained with halothane
(31 ± 6 per cent), than during isoflurane anaesthesia (18 ± 5 per cent). Atropine increased CO in both groups of patients,
but SV and EF remained unchanged. When compared with awake values, HR increased similarly and significantly (18 ± 4 per cent)
following atropine in both groups, and CO returned to control levels. Halothane decreased EF and increased LVEDV more than
isoflurane at 1.5 MAC end— expired anaesthetic levels. Atropine did not diminish the myocardial depression produced by halothane
or isoflurane. The increase in CO following atropine during halothane and isoflurane anaesthesia in infants and small children
is the result of increases in HR alone.
Nous avons utilisé un appareil à échocardiographie bi-dimensionnelle couplé à un Doppler pulsé chez des bébés et de jeunes
enfants pour évaluer l’impact hémodynamique de l’halothane (n = 15) et de l’isoflurane (n = 16) et la modification possible
de ces effets par l’atropine. Nous avons mesure la frequence cardiaque (FC), la pression artérielle moyenne (PAM), la dimension
de la cavité ventriculaire gauche (par écho bi-dimensionnelle) et la vélocité du flot sanguin pulmonaire (par Doppler) et
ce, en trois occasions soit avant l’induction, après l’instauration de 1.5 MAC d’halothane ou d’isoflurane et finalement,
deux minutes après l’injection IV de 0.02 mg·kg−1 d’atropine. On ne nota une baisse de la frequence cardiaque qu’avec l’halothane tandis que la PAM, le débit cardiaque (DC)
et le volume d’éjection (VE) diminuaient autant avec l’un ou l’autre anesthésique. La diminution de la fraction d’éjection
(FE) et l’augmentation du volume télédiastolique du ventricule gauche (VTDVG) significatives pour les deux groupes, étaienl
plus marqué avec l’halothane qu’avec l’isoflurane: FE 32 ± 5 pour cent vs18 ±5 pour cent; VTDVG 18 ± 7 pour cent vs 7 ± 5
pour cent. Avec l’atropine, la FC monta plus dans le groupe halothane (31 ± 6 pour cent) que dans le groupe isoflurane (18
± 5 pour cent), le DC augmentant dans les deux groupes, alors que le VE et la FE demeuraient inchangés. Comparée aux mesures
pré-induction, l’atropine amenait une hausse significative de la FC, semblable dans les deux groupes (18 ± 4 pour cent) et
restaurait le DC. Donc, chez les bebes et les jeunes enfants, a 1.5 MAC, l’halothane diminue la FE et augmente le VTDVG plus
que ne le fait l’isoflurane. L’atropine ne modifie pas la depression myocardique et elle ne restaure le DC que par une hausse
de la FC.
Supported by PHS Grant No. 8507300 from the College of Medicine, University of Iowa Hospital, Iowa City, IA. 相似文献
Supported by PHS Grant No. 8507300 from the College of Medicine, University of Iowa Hospital, Iowa City, IA. 相似文献