全文获取类型
收费全文 | 69915篇 |
免费 | 4429篇 |
国内免费 | 2236篇 |
专业分类
耳鼻咽喉 | 316篇 |
儿科学 | 1360篇 |
妇产科学 | 712篇 |
基础医学 | 11642篇 |
口腔科学 | 1381篇 |
临床医学 | 3874篇 |
内科学 | 8677篇 |
皮肤病学 | 749篇 |
神经病学 | 8822篇 |
特种医学 | 1147篇 |
外国民族医学 | 5篇 |
外科学 | 5274篇 |
综合类 | 10690篇 |
现状与发展 | 5篇 |
预防医学 | 2916篇 |
眼科学 | 1009篇 |
药学 | 10530篇 |
4篇 | |
中国医学 | 3847篇 |
肿瘤学 | 3620篇 |
出版年
2023年 | 847篇 |
2022年 | 2107篇 |
2021年 | 2053篇 |
2020年 | 1664篇 |
2019年 | 1791篇 |
2018年 | 1825篇 |
2017年 | 1865篇 |
2016年 | 1782篇 |
2015年 | 1876篇 |
2014年 | 3106篇 |
2013年 | 3799篇 |
2012年 | 3209篇 |
2011年 | 3739篇 |
2010年 | 3121篇 |
2009年 | 3144篇 |
2008年 | 3284篇 |
2007年 | 3234篇 |
2006年 | 3089篇 |
2005年 | 2893篇 |
2004年 | 2756篇 |
2003年 | 2550篇 |
2002年 | 2183篇 |
2001年 | 1825篇 |
2000年 | 1677篇 |
1999年 | 1425篇 |
1998年 | 1407篇 |
1997年 | 1367篇 |
1996年 | 1195篇 |
1995年 | 1188篇 |
1994年 | 951篇 |
1993年 | 767篇 |
1992年 | 682篇 |
1991年 | 660篇 |
1990年 | 542篇 |
1989年 | 444篇 |
1988年 | 436篇 |
1987年 | 338篇 |
1986年 | 467篇 |
1985年 | 888篇 |
1984年 | 781篇 |
1983年 | 582篇 |
1982年 | 602篇 |
1981年 | 498篇 |
1980年 | 417篇 |
1979年 | 312篇 |
1978年 | 254篇 |
1977年 | 172篇 |
1976年 | 180篇 |
1975年 | 138篇 |
1974年 | 126篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
101.
The best anastomotic agent to join nerve ends is controversial. This paper describes a controlled trial between a collagen tube wrap and a tissue glue to anastomose the rat facial nerve. There was no difference in the results using photographic, histological and electrophysiological techniques. 相似文献
102.
Abstract: The effects of pyridoxalated hemoglobin polyoxyethylene conjugate (PHP) and stroma-free hemoglobin (SFH) on vascular responsiveness to various vasoactive substances were examined in isolated perfused rat kidneys. The kidneys isolated from rats were perfused with 6% PHP, 6% SFH, and 6% hydroxyethylstarch (HES) solution at a constant flow rate. Vascular responsiveness to acetylcholine (ACh), nitroglycerin (NG), norepinephrine (NE), and angiotensin-II (ANG-II) was examined by measuring the perfusion pressure (PP). Effects of inhibition of endothelium-derived relaxing factor (EDRF) by NG -monomethyl L-arginine (L-NMMA) on NE-induced and ANG-II-induced renal vascular responses were examined. ACh and NG induced a dose-dependent decrease in perfusion pressure (PP) in all groups. NE and ANG-II induced an increase in PP in all groups, but NE-induced and ANG-II-induced responses in the PHP-perfused and SFH-perfused groups were significantly larger than those in the HES-perfused group. L-NMMA did not alter vascular responsiveness to NE and ANG-II. These results indicate that PHP and SFH do not inhibit EDRF induced by ACh, but hemoglobin moiety per se does augment the vascular responsiveness to NE and ANG-II in the isolated perfused rat kidney. 相似文献
103.
104.
牛磺酸对实验性高血压大鼠脑脊液和血浆内皮素含量的影响 总被引:4,自引:0,他引:4
目的探讨牛磺酸对实验性高血压大鼠脑脊液、血浆内皮素-1(ET-1)含量的影响.方法Wistar大鼠36只,随机分为高血压组,牛磺酸组和对照组3组,高血压组和牛磺酸组建立大鼠主动脉狭窄-高盐摄入性高血压模型,牛磺酸组饲料中加牛磺酸,观察3组大鼠脑脊液、血浆ET-1含量及血压的变化,测定脑组织和主动脉组织牛磺酸含量及主动脉肌条的舒缩功能.结果应用牛磺酸后,高血压大鼠pMA,脑脊液和血浆ET-1水平均下降(P<0.05),血管舒缩功能得以改善.结论牛磺酸可降低脑脊液、血浆ET-1水平,从而降低血压. 相似文献
105.
Piotr Kozlowski Alastair M. Buchan Ursula I. Tuor Dong Xue Zhi-Gao Huang Karen E. Chaundy John K. Saunders 《Magnetic resonance in medicine》1997,37(3):346-354
31P, 1H and lactate spectroscopic imaging was used to evaluate the effects of hypothermia on focal cerebral ischemia produced by middle cerebral artery occlusion. The effects on high energy phosphate metabolism, pH, lactate and NAA were investigated in 24 spontaneously hypertensive rats subjected to either permanent or transient ischemia. Under either normothermic (37.5°C) or hypothermic (32°C) conditions, with permanent 6-h occlusion, there was little difference between groups in either the NMR measurements or the volume of infarction. In animals that underwent 3 h of ischemia followed by 12 h of reperfusion, the ischemic changes in lactate, pH, NAA, and high-energy phosphate returned toward control values, and there was a protective effect of hypothermia (infarct volume of 211 ± 26 and 40 ± 14 mm3 in normothermic and hypothermic groups, respectively). Thus, hypothermia did not ameliorate the changes in lactate, pH, NAA, or high energy phosphate levels occurring during ischemia, however, during reperfusion there was an improvement in both the recovery of these metabolites and pathological outcome in hypothermic compared with normothermic animals. 相似文献
106.
目的:观察缺氧及停止缺氧后对大鼠心肌血流量的影响。方法:34只Wistar大鼠,随机分为4组:①平原对照组;②急性缺氧组;③慢性缺氧组;④返回平原组。以放射性生物微球法测定心肌血流量。结果:急性缺氧引起PaO2、心输出量及氧运送量降低,但左、右心室心肌血流量明显增加;慢性缺氧时右心室收缩压、血球压积、血液粘滞性及右心室生理指数明显增加,而心肌血流量接近正常。停止缺氧30d后,上述所有指标均与平原以 相似文献
107.
在微量注射大量肝脏mRNA之后,通过电压箝方法进行功能鉴定,两栖类卵母细胞成功地表达了AVPV1a受体。但在灌流AV4-8溶液时,却不能诱导卵母细胞产生内向振荡电流反应。提示AVP4-8不能通过AVPV1a受体而介导生理学效应。 相似文献
108.
109.
The influence of anaesthetic techniques and type of delivery on peripartum serum interleukin-6 concentrations 总被引:2,自引:0,他引:2
R. F. DE JONGH E. P. BOSMANS M. J. PUYLAERT W. U. OMBELET H. J. VANDEPUT R. A. BERGHMANS M. MAES R. J. HEYLEN 《Acta anaesthesiologica Scandinavica》1997,41(7):853-860
Background: Interleukin-6 is a pleiotropic cytokine with a wide range of physiological activities. It plays an important role in the immuno-neuro-humoral axis during stress and surgery.
Methods: Serum interleukin-6 in parturients was measured on hospital admission, immediately after birth and 12 and 24 hours later. All parturients had uncomplicated pregnancies, and delivered vaginally without (n=31) or with (n=20) epidural analgesia, or underwent Caesarean section under epidural (n=20) or general (n=10) anaesthesia.
Results: Serum interleukin-6 assayed immediately following Caesarean section was low, but peaked 12 hours later, irrespective of the anaesthetic technique or other foetomaternal characteristics. Patients who delivered vaginally showed the highest interleukin-6 levels immediately after delivery. These were positively correlated with serum interleukin-6 on admission and duration of labour. Serum interleukin-6 was significantly higher in parturients who had epidural analgesia, and was significantly lower in those receiving intravaginal prostaglandins compared to those without prostaglandins.
Conclusion: The interleukin-6 response after Caesarean section can be explained by a generalized acute phase response to surgery, with no anaesthetic, maternal or neonatal interference. The rapid increase in peripartum serum interleukin-6 levels after vaginal delivery reflects, in part, cervical ripening or labour, their physiological triggers and psychological or physical stress. Regional anaesthesia, duration of labour and exogenous prostaglandin administration can modulate the peripartum interleukin-6 response and subsequently the physiological effects of this cytokine. 相似文献
Methods: Serum interleukin-6 in parturients was measured on hospital admission, immediately after birth and 12 and 24 hours later. All parturients had uncomplicated pregnancies, and delivered vaginally without (n=31) or with (n=20) epidural analgesia, or underwent Caesarean section under epidural (n=20) or general (n=10) anaesthesia.
Results: Serum interleukin-6 assayed immediately following Caesarean section was low, but peaked 12 hours later, irrespective of the anaesthetic technique or other foetomaternal characteristics. Patients who delivered vaginally showed the highest interleukin-6 levels immediately after delivery. These were positively correlated with serum interleukin-6 on admission and duration of labour. Serum interleukin-6 was significantly higher in parturients who had epidural analgesia, and was significantly lower in those receiving intravaginal prostaglandins compared to those without prostaglandins.
Conclusion: The interleukin-6 response after Caesarean section can be explained by a generalized acute phase response to surgery, with no anaesthetic, maternal or neonatal interference. The rapid increase in peripartum serum interleukin-6 levels after vaginal delivery reflects, in part, cervical ripening or labour, their physiological triggers and psychological or physical stress. Regional anaesthesia, duration of labour and exogenous prostaglandin administration can modulate the peripartum interleukin-6 response and subsequently the physiological effects of this cytokine. 相似文献
110.
HemorrhagicfeverwithrenalsyndromevirusinfectioninliversstudiedbyinsituhybridizationandimmunohistochemistryYangShoujing(杨守京);L... 相似文献