全文获取类型
收费全文 | 21873篇 |
免费 | 2564篇 |
国内免费 | 818篇 |
专业分类
耳鼻咽喉 | 162篇 |
儿科学 | 72篇 |
妇产科学 | 2091篇 |
基础医学 | 2410篇 |
口腔科学 | 338篇 |
临床医学 | 2273篇 |
内科学 | 1007篇 |
皮肤病学 | 68篇 |
神经病学 | 1573篇 |
特种医学 | 631篇 |
外国民族医学 | 24篇 |
外科学 | 2766篇 |
综合类 | 4111篇 |
现状与发展 | 8篇 |
预防医学 | 1117篇 |
眼科学 | 80篇 |
药学 | 1320篇 |
21篇 | |
中国医学 | 1413篇 |
肿瘤学 | 3770篇 |
出版年
2024年 | 48篇 |
2023年 | 287篇 |
2022年 | 574篇 |
2021年 | 871篇 |
2020年 | 804篇 |
2019年 | 650篇 |
2018年 | 592篇 |
2017年 | 909篇 |
2016年 | 1003篇 |
2015年 | 985篇 |
2014年 | 1805篇 |
2013年 | 1535篇 |
2012年 | 1455篇 |
2011年 | 1572篇 |
2010年 | 1286篇 |
2009年 | 1096篇 |
2008年 | 1016篇 |
2007年 | 1100篇 |
2006年 | 1003篇 |
2005年 | 759篇 |
2004年 | 651篇 |
2003年 | 649篇 |
2002年 | 491篇 |
2001年 | 463篇 |
2000年 | 323篇 |
1999年 | 297篇 |
1998年 | 286篇 |
1997年 | 271篇 |
1996年 | 276篇 |
1995年 | 253篇 |
1994年 | 200篇 |
1993年 | 169篇 |
1992年 | 154篇 |
1991年 | 143篇 |
1990年 | 119篇 |
1989年 | 124篇 |
1988年 | 120篇 |
1987年 | 99篇 |
1986年 | 109篇 |
1985年 | 137篇 |
1984年 | 107篇 |
1983年 | 96篇 |
1982年 | 104篇 |
1981年 | 83篇 |
1980年 | 65篇 |
1979年 | 35篇 |
1978年 | 27篇 |
1977年 | 15篇 |
1976年 | 13篇 |
1973年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Shuichi Takishita Hiromi Muratani Hiroshi Teruya Shogo Sesoko Koshiro Fukiyama 《Clinical and experimental nephrology》1997,1(4):261-265
Background Stressful psychological stimuli produce an increase in renal sympathetic nerve activity (RSNA) and a decrease in renal blood
flow. Very few direct analyses of the relationship between RSNA and renal blood flow during the application of psychological
stimuli have been conducted by recording these 2 measurements simultaneously in the same individual animals.
Methods We simultaneously measured RSNA and renal blood flow as a Doppler shift in conscious, unrestrained, spontaneously hypertensive
rats. The rats were stressed by directing a continuous air jet at their faces for 20 seconds.
Results Air-jet stimulus increased RSNA 81%±15% (mean±standard error of the mean, n=10), mean arterial pressure (21±3 mm Hg), and
renal vascular resistance (37%±6%), and decreased renal blood flow (−15%±2%). The percentage change in RSNA correlated positively
with the change in mean arterial pressure (r=0.934,P<0.001) and percentage change in renal vascular resistance (r=0.912), and negatively with the percentage change in renal blood flow (r=−0.804). The denervation of renal nerves prevented renal blood flow from decreasing in response to air-jet stress.
Conclusions A reduction in renal blood flow in response to short-term air-jet stress is elicited mainly by neural mechanisms in spontaneously
hypertensive rats. Enhancement of RSNA by air-jet stimulus exerts a potent constricting effect on the renal vascular bed,
resulting in a reduction in renal blood flow. 相似文献
132.
应用流式细胞计对30例宫颈腺癌和混合癌细胞的DNA指数和细胞增殖周期各时相细胞分布比例进行分析,结果显示非整倍体肿瘤29例,占96.7%.流式细胞计在诊断恶性肿瘤方面是有价值的。细胞增殖周期比DNA指数对预后的估价更有意义.乳头型腺癌、分化I级的肿瘤,S+G2M比率最低,5年生存率最高. 相似文献
133.
Gary W Thickbroom Michelle L Byrnes Rick Stell Frank L Mastaglia 《Movement disorders》2003,18(4):395-402
Previous work has suggested that there may be a widespread disturbance of motor control mechanisms in patients with cervical dystonia. In the present study, we used transcranial magnetic stimulation to investigate the topography of the corticomotor projection to the abductor pollicis brevis (APB) muscle in 10 subjects with idiopathic torticollis. Threshold-adjusted stimuli were delivered at multiple scalp sites during a low-level voluntary contraction of the APB, and maps were generated of motor evoked potential amplitude versus scalp site. The cortical maps for the APB on the side opposite to the direction of head rotation were displaced laterally or posteriorly in all subjects and reverted to a more normal position after botulinum toxin injection of the cervical muscles in 5 subjects. The findings point to a reversible reorganisation of the corticomotor representation of the hand on the same side as the sternocleidomastoid (SCM) muscle that is involved in producing the dystonia. These results provide further evidence for the involvement of cortical centres and for a more widespread abnormality of motor control mechanisms in focal dystonia. The findings also support the notion that head turning is chiefly mediated by the hemisphere ipsilateral to the direction of the head rotation by means of a corticomotor projection to the contralateral SCM. 相似文献
134.
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
135.
Emergency airway management in patients with cervical spine injuries 总被引:10,自引:0,他引:10
136.
Kazumasa Shindo MD Shin-ichi Tsunoda MD Zenji Shiozawa MD 《Clinical autonomic research》1994,4(6):299-302
Microneurography was performed in a 39-year-old woman with demyelination of the pontine white matter associated with muscle spasms in the lower extremities. Single bursts on the microneurogram were observed immediately after cessation of the spasm with no systemic changes in the blood pressure or heart rate. Voluntary tonic flexion of the lower extremities induced similar bursts with small amplitudes. These reflex bursts possessed a characteristic of muscle sympathetic nerve activity, because the latency between the peak of each burst and the prior R-wave on the electrocardiograph was constant. The occurrence of these bursts suggests that a segmental compensatory mechanism in the spinal cord may stabilize the muscle blood flow influenced by muscle contraction. 相似文献
137.
Chinori Kurata MD PhD Sakae Shouda MD Tadashi Mikami MD Yasushi Wakabayashi MD Tomoyasu Nakano MD Tsuyoshi Sugiyama MD Kei Tawarahara MD PhD Kazuyuki Sakata MD PhD 《Journal of nuclear cardiology》1997,4(6):515
Background. [123I]Metaiodobenzylguanidine (MIBG) imaging has been used to assess cardiac sympathetic nerve abnormalities. We evaluated the clinical significance of myocardial MIBG imaging as a measure of cardiac sympathetic nervous system function by comparing it to heart rate variability and plasma norepinephrine level.Methods and Results. In 211 subjects, we analyzed heart rate variability with 24-hour electrocardiography, performed scintigraphy with MIBG, and measured plasma norepinephrine levels. Time and frequency domain measures of heart rate variability were calculated with the Marquette heart rate variability program (Marquette Electronics, Milwaukee, Wis.). Early and late myocardial MIBG uptakes were measured at 15 and 150 minutes after injection, respectively. MIBG clearance rate from the heart and heart-to-lung and heart-to-mediastinum ratios of MIBG activities were calculated. On the whole, heart rate variability, including low-frequency power, correlated positively, but modestly so, with late MIBG uptake and negatively with MIBG clearance rate. The plasma norepinephrine level correlated negatively with late MIBG uptake and with heart rate variability, including low-frequency power, and positively with MIBG clearance rate. Similar correlations were also observed in patient subgroups with coronary artery disease, diabetes mellitus, and renal failure, but these correlations were weak (R2 < 0.5).Conclusions. Increased cardiac sympathetic nervous system activity may be associated with increased myocardial MIBG clearance and decreased heart rate variability, including low-frequency power. Because these associations were not strong, however, the combination of heart rate variability with MIBG may allow an interactive assessment of the cardiac autonomic nervous system. 相似文献
138.
Thoracic epidural analgesia in aortocoronary bypass surgery II: effects on the endocrine metabolic response 总被引:3,自引:0,他引:3
R. STENSETH L. BJELLA E. M. BERG O. CHRISTENSEN O. W. LEVANG S. E. GISVOLD 《Acta anaesthesiologica Scandinavica》1994,38(8):834-839
Thoracic epidural analgesia (TEA) may offer haemodynamic benefits for patients with coronary heart disease going through major surgery. This may – in part – be secondary to an effect on the endocrine and metabolic response to surgery. We therefore investigated the effect of TEA on the endocrine metabolic response to aortocoronary bypass surgery (ACBS).
Thirty male patients (age < 65 years, ejection fraction > 0.5) were randomized into 3 groups; the HF group receiving a high dose fentanyl (55 μg–kg-1 ) anaesthesia, the HF + TEA group with the same fentanyl dose + TEA with 10 ml bupivacain 5 mg ml-1 , followed by 4 ml every hour, and the LF + TEA group receiving fentanyl 15 μg kg-1 + TEA. Adrenalin, noradrenalin, systemic vascular resistance (SVR), glucose, Cortisol, lactate and free fatty acids were followed during the operation and for 20 h postoperatively.
A significant increase in adrenalin, noradrenalin and SVR was found in the HF group whereas this increase was blocked in both epidural groups. An increase in glucose and Cortisol was noticed in all groups, but the increase was delayed in the epidural groups.
Our results suggest that a more effective blockade of the stress response during ACBS is obtained when TEA is added to general anaesthesia than with high dose fentanyl anaesthesia alone. 相似文献
Thirty male patients (age < 65 years, ejection fraction > 0.5) were randomized into 3 groups; the HF group receiving a high dose fentanyl (55 μg–kg
A significant increase in adrenalin, noradrenalin and SVR was found in the HF group whereas this increase was blocked in both epidural groups. An increase in glucose and Cortisol was noticed in all groups, but the increase was delayed in the epidural groups.
Our results suggest that a more effective blockade of the stress response during ACBS is obtained when TEA is added to general anaesthesia than with high dose fentanyl anaesthesia alone. 相似文献
139.
Adenoma malignum (minimal deviation adenocarcinoma) of the cervix responsive to hormonal treatment 总被引:1,自引:0,他引:1
Adenoma malignum (AM) is a rare variant of cervical adenocarcinoma with an unfavorable prognosis despite radiation therapy, surgery, or chemotherapy either alone or in combination. Hitherto, however, the effectiveness of hormonal therapy for this condition has not been evaluated. We report on a patient with cervical AM treated with progesterone before surgery. The progesterone therapy resulted in a complete clinical response and partial surgical response. Later on the treatment was changed to tamoxifen because of side effects of the progesterone treatment. The patient is still without evidence of disease 42 months after the start of the hormonal therapy. The progesterone receptor analysis on the biopsy was clearly positive. This is, to our knowledge, the first case of an AM responsive to hormonal treatment. Furthermore, this is the first case of an AM with bone metastases at the time of primary diagnosis. 相似文献
140.
Shuu-Jiun Wang Kwong-Kum Liao Hung-Hsiang Liou Shei-Shee Lee Ching-Piao Tsai Kon-Ping Lin Ko-Pei Kao Zin-An Wu 《Muscle & nerve》1994,17(4):411-418
Sympathetic skin response (SSR) and R–R interval variation (RRIV) were studied in 36 chronic, nondiabetic uremics to compare with their nerve conduction studies (NCS) and clinical dysautonomia. Abnormal SSR was noted in 5 (13.9%) patients, abnormal RRIV in 14 (38.9%), and abnormal NCS in 26 (72.2%). The patients were classified into three groups: group (GP) 1: “normal,” n = 21 (58.3%), normal RRIV and SSR; GP 2: “isolated parasympathetic dysfunction,” n = 10 (27.8%), abnormal RRIV and normal SSR; and GP 3: “sympathetic sudomotor dysfunction,” n = 5 (13.9%), abnormal SSR. A significant difference in age was found among the three groups (GP 3 > GP 2 > GP 1; P < 0.0001, ANOVA). After controlling the age factor, we still noted a tendency toward increasing NCS disturbances (distal latency and nerve conduction velocity of peroneal nerve; P < 0.05, multiple regression analysis) and frequencies of clinical autonomic symptoms (postural dizziness and impotence; P < 0.05, Mantel–Hanszel test) from GP 1 to GP 3. Patients with abnormal SSR (GP 3) displayed significantly higher frequencies of postural dizziness and impotence, indicating the relationship between an absence of SSR and clinical dysautonomia. © 1994 John Wiley & Sons, Inc. 相似文献