全文获取类型
收费全文 | 69301篇 |
免费 | 4112篇 |
国内免费 | 1364篇 |
专业分类
耳鼻咽喉 | 480篇 |
儿科学 | 1440篇 |
妇产科学 | 698篇 |
基础医学 | 6593篇 |
口腔科学 | 745篇 |
临床医学 | 9987篇 |
内科学 | 11761篇 |
皮肤病学 | 338篇 |
神经病学 | 3353篇 |
特种医学 | 2102篇 |
外国民族医学 | 2篇 |
外科学 | 7784篇 |
综合类 | 10820篇 |
现状与发展 | 4篇 |
一般理论 | 1篇 |
预防医学 | 5559篇 |
眼科学 | 2620篇 |
药学 | 6883篇 |
39篇 | |
中国医学 | 2898篇 |
肿瘤学 | 670篇 |
出版年
2024年 | 136篇 |
2023年 | 1038篇 |
2022年 | 1996篇 |
2021年 | 2783篇 |
2020年 | 2469篇 |
2019年 | 2036篇 |
2018年 | 2047篇 |
2017年 | 2020篇 |
2016年 | 2104篇 |
2015年 | 2102篇 |
2014年 | 4477篇 |
2013年 | 4812篇 |
2012年 | 3849篇 |
2011年 | 4258篇 |
2010年 | 3229篇 |
2009年 | 3145篇 |
2008年 | 3149篇 |
2007年 | 3134篇 |
2006年 | 2920篇 |
2005年 | 2391篇 |
2004年 | 2072篇 |
2003年 | 1779篇 |
2002年 | 1530篇 |
2001年 | 1427篇 |
2000年 | 1251篇 |
1999年 | 1095篇 |
1998年 | 911篇 |
1997年 | 946篇 |
1996年 | 805篇 |
1995年 | 835篇 |
1994年 | 743篇 |
1993年 | 640篇 |
1992年 | 631篇 |
1991年 | 554篇 |
1990年 | 523篇 |
1989年 | 452篇 |
1988年 | 476篇 |
1987年 | 418篇 |
1986年 | 376篇 |
1985年 | 420篇 |
1984年 | 466篇 |
1983年 | 263篇 |
1982年 | 367篇 |
1981年 | 288篇 |
1980年 | 267篇 |
1979年 | 232篇 |
1978年 | 204篇 |
1977年 | 141篇 |
1976年 | 113篇 |
1973年 | 102篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
观察了食饵性高血脂对新西兰兔血小板功能、纤溶系统和血液流变学的影响以及去纤酶的调节作用,并动态观察了指标的变化.结果发现,高血脂能引起兔的血小板数增加,粘附力增强,血液粘滞性增加,红细胞流动变慢,呈现高凝和低纤溶状态,且主动脉形成明显粥样斑块.去纤酶在降低血脂的同时,可明显降低血小板的粘附力,降低血液粘滞性,呈现低凝和高纤溶状态,其主动脉粥样斑块亦明显减轻和缩小.提示去纤酶既能降低血脂又能降低血粘稠度,促进纤溶,起到抗凝及防止血栓形成,抑制动脉硬化的形成和发展. 相似文献
22.
The prothrombin time (PT) and the activated partial thromboplastin time (APTT) for untreated male Wistar rats were determined on the Sysmex CA-5000 Instrument for blood taken from the orbital sinus, tail vein, vena cava and aorta. Boxplot and statistical analysis was performed. Only orbital sinus puncture yields unpredictable and unacceptable variation/prolongation of clotting times. 相似文献
23.
川芎嗪对脑外伤患者血栓素、前列腺环素及颅内压的影响 总被引:6,自引:0,他引:6
28例重度脑外伤患者分为川药嗪治疗组和一般治疗对照组,两组病人均于用药前和用药后3小时测定血浆和脑室内脑脊液(VCSF)中血栓素代谢产物(TXB_2)前列腺环素代谢产物6—酮—PGF_(la)(6KP)和颅内压。结果表明:两组治疗前血浆、VCSF中TXB_2及T/K均明显高于正常献血员对照组,川芎嗪能降低脑外伤患者血浆、VCSF中TXB_2及T/K值,对颅内压则无明显影响。提示川芎嗪能抑制脑外伤对血小板的激活、纠正循环血中TXA_2—PGI_2平衡失调,从而改善脑微循环。 相似文献
24.
25.
ABSTRACT. The effects of procedures which stimulate sympathetic activity, viz. mental stress induced by a colour-word conflict test (CWT) for 20 min, and orthostasis (ORT) for 8 min were studied in 8 young (16-20 yr) insulin-dependent diabetes mellitus (IDDM) patients and 9 age and sex-matched healthy controls. The IDDM patients showed no signs of neuropathy or retinopathy and their mean HbA1c value was 8.4 ±0.6% (normal value < 5.0 %). Blood pressure and heart rate increased significantly during CWT and ORT in both groups. The changes in systolic blood pressure and heart rate were comparable in both groups during CWT; the IDDM group showed a higher ( p < 0.05) heart rate after 8 min of orthostasis, however. CWT and ORT elicited equivalent increases in noradrenaline in venous plasma in both groups ( p < 0.05), but the IDDM patients had 50% lower values ( p < 0.01) at rest, during CWT and at rest after CWT than controls. CWT and ORT evoked equivalent plasma adrenaline increases in both groups. The lipolysis marker, plasma glycerol, was about 40 % lower ( p < 0.05) in the IDDM group before and after CWT. Yet, mental stress evoked equivalent increases in glycerol levels ( p < 0.01) in both groups. These findings indicate that sympathetic activity in the young diabetic patients without signs of neuropathy may be blunted. 相似文献
26.
27.
The purpose of the study was to compare the effect of voluntary pelvic floor muscle (PFM) contraction and vaginal electrical stimulation on urethral pressure. Twelve women with genuine stress incontinence, mean age 49.4 years (range 33–66) participated in the study. The urethral and bladder pressures were recorded simultaneously through a double-lumen 8 Ch catheter. The patients first performed three voluntary PFM contractions. Then two electrical stimulators, Conmax and Medicon MS 105, 50 Hz, were used in random order. A visual analog scale was used to measure pain and discomfort. Pain was reported to mean 6.8, SEM 0.64 (range 0.7–9.9) and mean 6.1, SEM 0.81 (range 0–9.1) with Conmax and Medicon MS 105, respectively. The mean paired difference in favor of voluntary contraction with Conmax was ?8.0, SD 6.7,P=0.0067, and with Medicon MS 105 it was ?12.2, SD 5.9,P=0.0022. The results demonstrated that voluntary PFM contraction increased urethral pressure significantly more than did vaginal electrical stimulation. 相似文献
28.
29.
B. Silke J. P. Spiers S. Boyd E. Graham G. McParland M. E. Scott 《Clinical autonomic research》1994,4(1-2):49-56
The accuracy and precision of the Finapres in recording rest and exercise blood pressure compared with the intra-arterial (aortic and brachial) and random-zero sphygmomanometer methods was assessed in 84 ischaemic patients in three different studies. Firstly, comparison at rest with the aortic intraarterial pressure in 50 ischaemic patients demonstrated that the Finapres systolic (136.5 ± 21.1 vs. 129.3 ± 19.0 mmHg;p < 0.001) and mean (92.4 ± 13.4 vs. 90.7 ± 11.4 mmHg;p < 0.001) arterial pressures were higher and diastolic pressures lower (70.4 ± 11.5 vs. 71.5 ± 9.8 mmHg;p < 0.001). The reproducibility of the Finapres and invasive method was similar for systolic (4.6% vs. 4.0%), diastolic (2.8% vs. 2.7%) and mean (3.3% vs. 3.0%) blood pressures. Second, in seven subjects studied twice at rest and during 4 min supine bicycle exercise, the exercise increase in blood pressure was greater on the Finapres compared with the brachial intra-arterial pressure (systolic +10.2 ± 6.3 vs. +3.6 ± 9.8 mmHg; diastolic +9.6 ± 11.1 vs. +0.2 ± 2.1 mmHg;p = 0.02 for each); however, at steady-state the peak/trough differences in pressure between the methods were similar. Thirdly, compared under rest conditions, to random zero sphygmomanometer (RZO), the Finapres systolic pressure was higher (6.8 ± 3.5 mmHg) and diastolic pressure lower (–6.0 ± 1.9 mmHg). During upright bicycle exercise, the difference between the Finapres and RZO in systolic blood pressure increased at each level of exercise (+14.3 ± 4.2, +17.9 ± 4.0 and +22.2 ± 4.1 mmHg respectively at each exercise stage:p < 0.01). For RZO, diastolic blood pressure fell as exercise workload increased whereas Finapres diastolic blood pressure increased on exercise (3.1 ± 2.6, 7.0 ± 2.1 and 8.1 ± 2.0 mmHg respectively:p < 0.01). Thus there were systematic differences between the values recorded by the Finapres and proximal blood pressure methods and limited agreement in the rest to exercise increments related to light exercise. Calibration of the Finapres values in terms of the other methods is limited by the variable relationship to these related changes in arterial distensibility. 相似文献
30.
Summary: We studied the effect of antiepileptic drugs (AEDs) on internal carotid artery (ICA) blood flow velocity, as an index of total cerebral blood flow (CBF). The subjects were 45 newly diagnosed children with febrile convulsion or epilepsy who were seizure-free for a period long enough not to affect the results. They had no neurologic deficit, received fixed monotherapy, and were examined by a noninvasive Doppler ultrasound method, in comparisonwith 13 age-matched normal volunteers with no AED. In 30 patients, the measurements were performed before and after AED administration [10 with phenobarbital (PB), 10 with carbamazepine (CBZ), and 10 with valproate (VPA)], and performed before and after AED discontinuation in the remaining 15 patients (all with PB). Normal volunteers underwent the two consecutive examinations with a mean interval equal to that of the entire patient group, and there was no difference in velocity values between the measurements. In patients receiving CBZ or VPA, a significant reduction was noted in blood flow velocity after drug administration. Although velocity values in the patients receiving PB did not change after drug administration, they were significantly increased after complete discontinuation. In the present study, a slight but significant reduction in CBF caused by AED administration at therapeutic doses in children was suggested. 相似文献