全文获取类型
收费全文 | 39369篇 |
免费 | 2495篇 |
国内免费 | 1437篇 |
专业分类
耳鼻咽喉 | 67篇 |
儿科学 | 959篇 |
妇产科学 | 682篇 |
基础医学 | 2097篇 |
口腔科学 | 129篇 |
临床医学 | 4392篇 |
内科学 | 11476篇 |
皮肤病学 | 104篇 |
神经病学 | 1237篇 |
特种医学 | 902篇 |
外科学 | 2684篇 |
综合类 | 7395篇 |
现状与发展 | 5篇 |
预防医学 | 2432篇 |
眼科学 | 726篇 |
药学 | 5626篇 |
27篇 | |
中国医学 | 2127篇 |
肿瘤学 | 234篇 |
出版年
2024年 | 69篇 |
2023年 | 537篇 |
2022年 | 920篇 |
2021年 | 1328篇 |
2020年 | 1326篇 |
2019年 | 1177篇 |
2018年 | 1236篇 |
2017年 | 1207篇 |
2016年 | 1289篇 |
2015年 | 1279篇 |
2014年 | 2559篇 |
2013年 | 3561篇 |
2012年 | 2164篇 |
2011年 | 2252篇 |
2010年 | 1924篇 |
2009年 | 1745篇 |
2008年 | 1681篇 |
2007年 | 1876篇 |
2006年 | 1668篇 |
2005年 | 1410篇 |
2004年 | 1321篇 |
2003年 | 1217篇 |
2002年 | 1009篇 |
2001年 | 959篇 |
2000年 | 809篇 |
1999年 | 674篇 |
1998年 | 601篇 |
1997年 | 642篇 |
1996年 | 533篇 |
1995年 | 553篇 |
1994年 | 477篇 |
1993年 | 334篇 |
1992年 | 345篇 |
1991年 | 279篇 |
1990年 | 248篇 |
1989年 | 211篇 |
1988年 | 221篇 |
1987年 | 186篇 |
1986年 | 169篇 |
1985年 | 238篇 |
1984年 | 213篇 |
1983年 | 110篇 |
1982年 | 151篇 |
1981年 | 138篇 |
1980年 | 143篇 |
1979年 | 71篇 |
1978年 | 55篇 |
1977年 | 56篇 |
1976年 | 51篇 |
1975年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
玉郎伞提取物对大鼠自发性高血压的影响 总被引:3,自引:0,他引:3
目的:研究玉郎伞提取物(YLS)对自发性高血压大鼠(SHR)及正常大鼠血压(BP)的影响。方法:应用颈动脉插管测压法,连接MS2000多媒体生物信号记录系统测定静注YLS前及药后20s、30s、lmin、2min、5min时的收缩压(SP)、舒张压(DP)、平均动脉压(MP)。结果:YLS使SHR及正常大鼠血压明显降低(P<0.01),降压作用维持时间较短,给药后5min血压基本恢复正常;YLS对去甲肾上腺素(NA)和异丙肾上腺素(ISO)的作用无明显影响。结论:YLS对正常大鼠及SHR血压有明显的降低作用。 相似文献
72.
重度妊娠高血压综合征患者胎盘表皮生长因子受体的表达 总被引:1,自引:1,他引:0
目的:研究胎盘表皮生长因子受体(EGFR)蛋白及基因的表达在置度妊娠高血压综合征(妊高征)发病中的作用以及对妊高征胎儿生长发育的影响。方法:采用免疫组织化学法和逆转录-聚合酶链反应(RT-PCR)技术测定21例重度妊高征患者[分2组,重度妊高征合并胎儿宫内发育迟缓(IUGR)组9例和重度妊高征未合并IUGR组12例]胎盘EGFR的表达,并与15例正常妊娠者(对照组)比较。结果:与对照组相比,重度妊高征患者胎盘EGFR蛋白及其mRNA的表达显著降低(P<0.01),重度妊高征合并EGFR组与重度妊高征未合并IUGR组之间胎盘EGFR的表达差异无显著性(P>0.05)。结论:胎盘滋养层细胞EGFR表达显著降低,可能是重度妊高征发病的重要因素;如果EGFR的低表达发生较早,容易发生IUGR。 相似文献
73.
D. E. Uehlinger P. Weidmann M. P. Gnaedinger 《European journal of clinical pharmacology》1989,36(2):119-125
Summary Co-dergocrine has recently been demonstrated acutely to lower plasma norepinephrine (NE) and blood pressure (BP) in patients
with essential hypertension, and similar results have been obtained during chronic administration of co-dergocrine to healthy
men. The present study investigated the effect of 3 weeks of treatment with co-dergocrine 4 mg/day on BP, plasma catecholamines,
certain other BP-regulating factors and serum lipoproteins in patients with essential hypertension.
Compared to placebo conditions, co-dergocrine decreased supine BP and heart rate by −7% and the upright plasma NE level by
−24%. Supine plasma NE also fell (−24%). Total cholesterol and the LDL + VLDL-cholesterol lipoprotein fraction were lowered
by −6%.
No significant change was observed in plasma renin activity, angiotensin II, aldosterone and epinephrine levels, whole blood
and plasma volume, exchangeable sodium, and the cardiovascular responsiveness to NE, angiotensin II and isoproterenol.
The findings suggest that in patients with essential hypertension, chronic treatment with co-dergocrine may slightly decrease
sympathetic outflow and, at least in the short-term, lower the potentially atherogenic serum LDL + VLDL − cholesterol fraction. 相似文献
74.
Summary The pharmacokinetics of ketanserin and its main metabolite ketanserin-ol, and the antihypertensive effects of intravenous, single oral and chronic oral (40 mg once daily) administration of ketanserin, have been investigated in a single blind study of 10 patients with uncomplicated mild hypertension. Ketanserin had a terminal half-life of 29.2 h, a plasma clearance of 518 ml/min and a volume of distribution of 18.0 l/kg. Chronic oral intake of 40 mg ketanserin (tablet formulation) gave a peak concentration of unchanged ketanserin of 88 ng/ml after 1.1 h. Its absolute bioavailability was 48%.During chronic therapy the maximal concentration of ketanserin-ol was 208 ng/ml and its half-life of elimination was 35.0 h. As this metabolite can be oxidized back to ketanserin, it contributes to the prolonged half-life of unchanged ketanserin seen during chronic therapy.The blood pressure was reduced by approximately 15% by oral ketanserin. The maximal reduction in blood pressure coincided with the peak concentration of unchanged ketanserin. During chronic therapy with 40 mg once daily blood pressure was reduced over 24 h. The heart rate was slightly reduced and the cardiovascular responses and the plasma noradrenaline concentrations during isometric exercise were only slightly influenced by ketanserin therapy.Thus, unchanged ketanserin has a relatively long half-life during chronic oral therapy and its pharmacokinetics in middle-aged hypertensive patients is similar to that in normal young volunteers. 相似文献
75.
目的 探讨他丁类降脂药是否具有改善高血压患者血管功能的作用。 方法 ~ 级轻中度高血压患者 5 5人 ,在常规抗高血压治疗的同时 ,加用氟伐他丁 (Flu) 2 0~ 4 0 m g/ d,并与 37例单纯常规抗高血压治疗病人对比。采用彩色多普勒超声检查肱动脉 (BA)和胫前动脉 (TA)的管腔内径。采用充血法测定血管内皮依赖性舒张功能 (Δ Dia- P)。 结果 Flu治疗 3个月 ,血脂水平明显下降 ,可见 TA血管 Δ Dia- P改善 (% :8.5 1± 3.0 7vs14 .19± 5 .4 1,n=6 ,P<0 .0 5 ) ,以后均维持在较高水平。治疗 3个月时 BA的 ΔDia- P也有改善 ,但未达统计学差异水平 ,治疗 12个月时 BAΔ Dia- P明显改善。多元逐步回归分析在所观察的参数中未发现和血管功能有固定关系的因素。 结论 Flu能够使接受常规降压药治疗的高血压患者的 Δ Dia- P改善。小剂量长时间的 Flu可以改善血管舒张功能。药物干预后 TA的功能变化出现较早 ,是反映血管功能变化的敏感靶点 相似文献
76.
目的 :探讨内关穴敷磁的降压效应。方法 :40只清醒家兔和 40只麻醉家兔 (其中 2 0只去减压神经 ) ,静脉注射去甲肾上腺素或苯肾上腺素引起急性实验性高血压 ,并于内关穴敷磁 (0 .1~ 0 .2T) ,记录血压、心率和敷磁前及 1h后的血液粘度的变化。结果 :敷磁 1h后各实验组平均动脉压 (MAP)显著下降 (P <0 .0 1)。麻醉和清醒家兔MAP降幅无差异 (P >0 .0 5 ) ,但显著高于去减压神经家兔MAP的降幅 (P <0 .0 1或 0 .0 5 ) ,各实验组全血比粘度显著下降 (P <0 .0 1或 0 .0 5 ) ,实验组与各自对照组心率敷磁前后无差异 (P >0 .0 5 )。结论 :磁场具有降压作用 ,但对心率无影响 ,其降压效应与减压神经的抑制和全血粘度的降低有关 ,与化学感受性升压反射无关 相似文献
77.
The haemodynamic problems associated with anaesthesia and neuroblastoma were reviewed in 52 children who underwent 138 operations at The Hospital for Sick Children, London, UK. At diagnosis 42 patients (81%) had elevated urinary catecholamine metabolites; nine (17%) were hypertensive, of whom eight were treated with adrenergic blockade. The incidence of intra-operative hypertension due to excess catecholamine release was 9% (13/138), and was confined to the group undergoing tumour excision (29%; 13/45). Hypertension was observed more frequently in patients who had not received chemotherapy. It was effectively controlled by labetalol. Patients symptomatic of catecholamine secretion before surgery should be managed in a similar manner for those with a phaeochromocytoma. Surgical manipulation of the tumour predisposes to paroxysmal hypertension. Careful monitoring is advised. 相似文献
78.
高血压病人药物治疗期间动态血压变化 总被引:49,自引:0,他引:49
目的评价高血压病人药物治疗期间24h动态血压变化。方法26例住院的高血压病人经药物治疗4周连续3d随测血压,血压正常后进入本研究。治疗前后进行24h动态血压监测。结果患者随测血压(8~9AM,3~4PM)血压恢复到正常水平,但动态血压显示在一段时间内(6~8AM,6~11PM)平均收缩和舒张压仍明显高于正常人平均水平(P<0.01),而该时间段易被临床医生忽视。结论随测血压不能实际全面反映高血压病人药物治疗的疗效,24h动态血压的监测可以正确评价高血压病人药物治疗的效果并根据高血压分布的时间来调整降压药的种类和剂量。 相似文献
79.
An olfactory deficit is present in patients with essential tremor (ET), but it is often milder than that in patients with Parkinson's disease (PD). In both, the deficit occurs early in the disease. Isolated rest tremor without other signs of parkinsonism can occur in patients with ET. If the rest tremor in these patients represents a manifestation of ET rather than early PD, we hypothesized that their University of Pennsylvania Smell Identification Test (UPSIT) scores would be similar to those of ET patients without rest tremor. The mean UPSIT score in 13 ET patients with isolated rest tremor did not differ from that of 58 ET patients without rest tremor (29.3 +/- 4.3 vs. 29.4 +/- 6.4; P = 0.69). Several ET patients with rest tremor had UPSIT scores that fell outside of the range that is seen in 95% of patients with PD. These data raise the possibility that some ET patients with isolated rest tremor may not have early PD and that the pathological process that is responsible for their ET is also involving the basal ganglia. 相似文献
80.
82例高血压患者16项人格特质测验 总被引:1,自引:0,他引:1
研究目的应用卡特尔16项人格特质测验探讨原发性高血压患者的人格特征。研究背景高血压病是危害人类健康的常见病之一,发病率逐年上升,但其病因至今尚未阐明,故有必要从心理、人格方面来探讨高血压的发病原因,以利于高血压病的防治。研究方法本文对82例均由2名以上内科医师确诊为原发性高血压、且现在高压仍保持在20/12.7kPa以上的患者进行卡特尔16项人格特质测验,并与78例人群对照分析。结果高血压患者在C-稳定性、E-峙强性、Q-紧张性以及在双重人格因素类型中的适应与焦虑方面与正常对照组有显著差异(P<0.05)。结论心理-社会因素是促使高血压发生的重要因素,它对高血压病因的阐明有重要意义,同时也使我们越来越重视运用心理、行为疗法,如生物反馈、各种松驰疗法等去防治高血压。 相似文献