全文获取类型
收费全文 | 19231篇 |
免费 | 1373篇 |
国内免费 | 412篇 |
专业分类
耳鼻咽喉 | 217篇 |
儿科学 | 118篇 |
妇产科学 | 251篇 |
基础医学 | 817篇 |
口腔科学 | 550篇 |
临床医学 | 2010篇 |
内科学 | 946篇 |
皮肤病学 | 273篇 |
神经病学 | 629篇 |
特种医学 | 519篇 |
外国民族医学 | 4篇 |
外科学 | 5694篇 |
综合类 | 4404篇 |
一般理论 | 4篇 |
预防医学 | 1017篇 |
眼科学 | 366篇 |
药学 | 1958篇 |
53篇 | |
中国医学 | 399篇 |
肿瘤学 | 787篇 |
出版年
2024年 | 40篇 |
2023年 | 333篇 |
2022年 | 520篇 |
2021年 | 691篇 |
2020年 | 722篇 |
2019年 | 645篇 |
2018年 | 604篇 |
2017年 | 663篇 |
2016年 | 672篇 |
2015年 | 670篇 |
2014年 | 1384篇 |
2013年 | 1226篇 |
2012年 | 1234篇 |
2011年 | 1317篇 |
2010年 | 1068篇 |
2009年 | 973篇 |
2008年 | 919篇 |
2007年 | 943篇 |
2006年 | 898篇 |
2005年 | 802篇 |
2004年 | 548篇 |
2003年 | 469篇 |
2002年 | 455篇 |
2001年 | 397篇 |
2000年 | 298篇 |
1999年 | 263篇 |
1998年 | 258篇 |
1997年 | 254篇 |
1996年 | 205篇 |
1995年 | 192篇 |
1994年 | 147篇 |
1993年 | 157篇 |
1992年 | 116篇 |
1991年 | 136篇 |
1990年 | 111篇 |
1989年 | 97篇 |
1988年 | 104篇 |
1987年 | 83篇 |
1986年 | 69篇 |
1985年 | 75篇 |
1984年 | 66篇 |
1983年 | 48篇 |
1982年 | 27篇 |
1981年 | 25篇 |
1980年 | 31篇 |
1979年 | 13篇 |
1978年 | 13篇 |
1977年 | 12篇 |
1976年 | 6篇 |
1974年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
目的 通过监测脑血流速度、颈静脉球部血氧饱和度(SjvO2)、血压、心率(HR)和不良反应发生率等,综合评价艾司洛尔用于控制开颅手术苏醒期患者脑过度灌注的效果.方法 选择择期在全身麻醉下行开颅肿瘤切除术的患者,随机分为艾司洛尔组(E组,20例)和对照组(C组,20例).E组患者从拔管即刻起给予艾司洛尔0.6 mg·kg1·h-1静脉持续滴注15 min C组患者从拔管即刻起给予0.9%氯化钠溶液静脉持续滴注.分别监测两组患者术前、术后拔管即刻及拔管后15、30、45、60 min时的大脑中动脉平均血流速度(MCAVm)、SivO2平均动脉压(MAP)及HR,并记录不良反应发生例数.结果 E组术后15和30 min的MCA Vm、sjvO2及HR均显著低于C组(P值均<0.01),术后15 Min的MAP显著低于C组(P<0.05).无一例患者发生与艾司洛尔相关的药物不良反应.结论 艾司洛尔是控制术后脑过度灌注的理想药物. 相似文献
42.
M. Pitkänen M.D. P. Rosenberg M. Silvanto M. Tuominen 《Acta anaesthesiologica Scandinavica》1992,36(6):526-529
Forty elderly patients, scheduled for orthopaedic surgery of the hip or knee were studied. Twenty patients received a single-dose spinal anaesthesia with 3 ml of plain 0.5% bupivacaine (SDSA group). Twenty patients received continuous spinal anaesthesia using a 32- or 22-gauge catheter. A bolus of 1.0 ml of plain 0.5% bupivacaine was given to ten patients and 0.5 ml to another ten, continued by an infusion at a rate of 2 ml/h. The spread of analgesia and haemodynamic changes (central venous pressure, arterial pressures, need for sympathomimetic medication) were registered. The mean dose of bupivacaine was 2.9 ml (range 1.5-5 ml) in the CSA group (3.0 ml in the SDSA group). Eight patients in the CSA group needed medication for pain during surgery compared to five patients in the SDSA group (n.s.). The median level of pinprick analgesia at 60 min was T11 in the CSA and T6.5 in the SDSA group (P less than 0.01). The mean maximum decreases in CVP and MAP were quite similar in the CSA and SDSA group (2.1 vs 2.8 mmHg (0.3 vs 0.4 kPa) and 17 vs 21 mmHg (2.3 vs 2.8 kPa), respectively) (n.s.). Six patients in the SDSA group and four patients in the CSA group needed sympathomimetic medication. It is concluded that titration of bupivacaine for spinal anaesthesia caused only minor haemodynamic changes which were similar to those after single-dose spinal bupivacaine. 相似文献
43.
R. MILASZKIEWICZ N. PAYNE B. LOUGHNAN A. BLACKETT N. BARBER F. CARLI 《Anaesthesia》1992,47(12):1042-1046
We studied 86 primiparous women with uncomplicated pregnancy and labour requesting extradural analgesia in labour. All the women were over 36 weeks of gestation with a cephalic-presenting singleton fetus. The women were allocated randomly to two groups: group A, who received an extradural infusion of lignocaine 0.75%, after an initial dose of 10 ml of lignocaine 1.5%, and group B, who received an infusion of bupivacaine 0.125% after an initial dose of 10 ml of bupivacaine 0.25%. All the women had their labour actively managed. Assessment of analgesia during labour and delivery, and the requirements for additional top-ups were noted, as were mode of delivery, requirement for oxytocic augmentation and incidence of fetal distress. Maternal and umbilical cord plasma concentrations of lignocaine were measured at delivery in 12 women receiving extradural lignocaine. There were no statistically significant differences between the two groups in terms of the mode of delivery, incidence of fetal distress, fetal heart rate abnormalities, or Apgar scores of the babies. Women in the bupivacaine group had a significantly better quality of analgesia during both the first and second stages of labour (p = 0.0005) and required fewer top-ups than those in the lignocaine group. However, the requirement for oxytocin augmentation during the first and second stages of labour was significantly less in the lignocaine group (p = 0.004). Similarly, the duration of the second stage was shorter compared with the bupivacaine group. In spite of high plasma concentrations of lignocaine, no side effects were noted in either mothers or babies. 相似文献
44.
E. B. Andersen F. Boesen O. Henriksen 《Clinical physiology and functional imaging》1991,11(5):451-458
Summary. The effect of age and sex on relative changes in blood flow and vascular resistance in skeletal muscle and subcutaneous tissue during postural changes and during local increase in transmural pressure was studied in 33 healthy subjects. The intra-individual variation was studied in five subjects. Blood flow was measured by the local 133Xenon wash-out method. No relation to age or sex was seen in the centrally elicited sympathetic vasoconstrictor responses in subcutaneous tissue and skeletal muscle and in the locally elicited vasoconstriction in subcutaneous tissue. A small, but statistically significant, correlation to sex and age was found in the local sympathetic vasoconstrictor response in skeletal muscle. The age correlation was caused only by an attenuated response in the young subjects below 40 years of age and may be fortuitous. The intra-individual variation was acceptably small. Based on the present results, a reduction in blood flow in skeletal muscle and subcutaneous tissue during centrally or locally elicited sympathetic vasoconstriction of 10% or less should be considered abnormal. The local 133Xenon wash-out method is of value in examining patients suspected of dysfunction in the sympathetic part of the autonomic nervous system. 相似文献
45.
S. A. Carter 《Clinical physiology and functional imaging》1991,11(3):253-261
Summary. The effect of changes in local and body temperature on the toe systolic pressures was studied in 20 subjects with and 30 without Raynaud's syndrome in the toes. The pressures were significantly lower in the group with Raynaud's syndrome under all experimental conditions (P < 0·01). The pressures were significantly lower during body cooling than during body warming in both groups (P < 0·01). The mean decrease with body cooling was 58 mmHg in the group with Raynaud's syndrome and 24 mmHg in the control subjects (P < 0·01). During body cooling pressures fell to less than 30 mmHg in 70% of subjects with Raynaud's syndrome and in 3% of the controls. Local cooling from 30 to 10°C during body cooling resulted in a significant mean decrease in pressure of over 40 mmHg in both groups (P < 0·01) and the pressure fell below 30 mmHg in over 90% of the group with and in 26% of those without Raynaud's attacks. The results indicate the importance of body cooling and local temperature in the mechanism of vasospasm in the toes. They are also relevant to the diagnosis of Raynaud's syndrome in the lower limbs and have implications for the testing of patients with arteriosclerotic occlusion since erroneously low pressure values could be obtained in tests when the feet are cold. 相似文献
46.
Bruce G. Haffty M.D. Peter L. Perrotta M.D. † Barbara Ward M.D. ‡ Meena Moran M.D. Malcolm Beinfield M.D. ‡ Charles McKhann M.D. ‡ Diana Fischer Ph.D. Darryl Carter M.D. † 《The breast journal》1997,3(1):7-14
Abstract: Between 1970 and 1990, 1,008 patients with early-stage breast cancer were treated by conservative surgery without axillary dissection followed by radiation therapy to the intact breast in the Department of Therapeutic Radiology at Yale-New Haven Hospital. The patient population, broken down by histologic subtype, was as follows: 761 patients presented with infiltrating ductal carcinoma, 70 patients with pure intraductal, 38 intraductal with focal invasion, 54 infiltrating lobular, 21 tubular, 17 medullary, 16 mucinous, and 29 with other various histologic subtypes. Patients were followed on a regular basis by the referring physicians and radiation oncologists. Diagnostic studies for distant metastases were performed as clinically indicated. Annual mammography was a routine component of the follow-up program. As of 3/96, with a median follow-up of 10.5 years, 83 patients developed an ipsilateral breast tumor recurrence, and 109 patients developed distant metastases resulting in an overall 10-year breast recurrence-free rate of 84%, and a 10-year distant metastasis-free rate of 78%. There were significant differences in clinical stage, pathological nodal involvement, and administration of systemic therapy between various histologic subtypes. As expected, those patients with histologies of low metastatic potential (such as intraductal, tubular, and mucinous) had significantly superior distant recurrence-free survival rates. With respect to breast relapse rates, there were no statistically significant differences in the 5- and 10-year breast recurrence-free rates between any of the histologic subtypes. Patients with intraductal carcinoma with or without focal invasion had similar breast relapse rates as those with other histologic subtypes. Patients with lobular carcinoma in situ as a histologic component also had a similar overall breast relapse-free recurrence rate. In conclusion, long-term follow-up of conservatively treated breast cancer patients demonstrates no significant differences in ipsilateral breast tumor recurrence rates between various histologic subtypes. There are no histologies which had a statistically significantly higher breast-relapse rate than infiltrating ductal carcinomas and therefore no primary histologic subtype represents a relative contraindication to breast conservation therapy. 相似文献
47.
Topographical analysis of the EEG effects of a subconvulsive dose of lidocaine in healthy volunteers
O. DETSCH U. ERKENS U. JACOFSKY A. THIEL E. KOCHS G. HEMPELMANN 《Acta anaesthesiologica Scandinavica》1997,41(8):1039-1046
Background: The purpose of the present study was to assess the effects of intravenous lidocaine on spatial changes of electroen-cephalographic power and on psychomotoric status in conscious volunteers.
Methods: In 11 healthy volunteers lidocaine (2-min bolus, 100 mg; 15-min infusion, 40 μg kg-1 min-1 ) or placebo were given intravenously in a randomized, single-blinded, two-way crossover study. Haemodynamics and lidocaine plasma concentrations were measured at baseline and within a period of 30 min following bolus injection. Vigilance and emotional status were tested using visual analogue scales (VAS). Toxic CNS effects were evaluated by a questionnaire. The raw EEG (17 leads, reference Cz ) and computed power spectra were continuously recorded.
Results: The chosen lidocaine dosage led to nearly constant plasma concentrations (unbound lidocaine 2.5 min and 15 min after bolus 0.36±0.14 μg/ml and 0.30±0.06 μg/ml, respectively [mean±SD]). The placebo caused no symptoms, changes in VAS-scores or EEG-parameters. Lidocaine induced pronounced subjective symptoms and significant increases in delta activity for 15 min, most dominant at the frontotemporal and occipital leads (max. +219% O1 ). Frontal and occipital beta1 and beta2 power (max. +131% and +124% at O1 , respectively) was immediately increased after the bolus injection. No EEG changes occurred at central region Cz , and no interhemispheric EEG differences were noted. Theta, alphal, and alpha2 power remained unchanged.
Conclusion: The current data demonstrate simultaneous changes in psychomotoric status as well as delta and beta spectral power during lidocaine infusion. These data could be an indication that the pronounced frontotemporal and occipital EEG changes are the electroencephalographic expression of subjective sensations. 相似文献
Methods: In 11 healthy volunteers lidocaine (2-min bolus, 100 mg; 15-min infusion, 40 μg kg
Results: The chosen lidocaine dosage led to nearly constant plasma concentrations (unbound lidocaine 2.5 min and 15 min after bolus 0.36±0.14 μg/ml and 0.30±0.06 μg/ml, respectively [mean±SD]). The placebo caused no symptoms, changes in VAS-scores or EEG-parameters. Lidocaine induced pronounced subjective symptoms and significant increases in delta activity for 15 min, most dominant at the frontotemporal and occipital leads (max. +219% O
Conclusion: The current data demonstrate simultaneous changes in psychomotoric status as well as delta and beta spectral power during lidocaine infusion. These data could be an indication that the pronounced frontotemporal and occipital EEG changes are the electroencephalographic expression of subjective sensations. 相似文献
48.
本文报道23例颈椎病手术患者采用1%普鲁卡因与2%利多卡因混合液局麻加静脉哌替啶强化取得满意的效果。文中围绕呼吸管理问题对前、后手术入路的麻醉用药、输血、补液及头部固定等注意事项均作了具体介绍。 相似文献
49.
50.
全身麻醉插管术后院内获得性肺部感染探讨 总被引:17,自引:3,他引:14
全身麻醉气管插管术后下呼吸道感染具有较高发生率。分析526例手术时间超过4小时普外科病例,经u检验发现全身麻醉气管插管术后患者肺部感染率明显高于持续性硬膜外麻醉术后患者,影响因素主要与全麻插管用具及麻醉机消毒情况有关,也与术前存在慢性阻塞性肺部疾患和术后保留气管插管有关。降低全麻术后肺部感染应重视无菌操作,尽可能对麻醉机管道进行常规消毒。 相似文献