首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   151956篇
  免费   10161篇
  国内免费   4979篇
耳鼻咽喉   579篇
儿科学   3425篇
妇产科学   1018篇
基础医学   8909篇
口腔科学   659篇
临床医学   22688篇
内科学   39429篇
皮肤病学   440篇
神经病学   8855篇
特种医学   8592篇
外国民族医学   7篇
外科学   13506篇
综合类   29009篇
现状与发展   17篇
一般理论   1篇
预防医学   5494篇
眼科学   1202篇
药学   13373篇
  159篇
中国医学   6543篇
肿瘤学   3191篇
  2024年   358篇
  2023年   2259篇
  2022年   4240篇
  2021年   6348篇
  2020年   5659篇
  2019年   4490篇
  2018年   4374篇
  2017年   4494篇
  2016年   4943篇
  2015年   4950篇
  2014年   9898篇
  2013年   9974篇
  2012年   8761篇
  2011年   9591篇
  2010年   7958篇
  2009年   7674篇
  2008年   7777篇
  2007年   7945篇
  2006年   7522篇
  2005年   6542篇
  2004年   5412篇
  2003年   4977篇
  2002年   3821篇
  2001年   3583篇
  2000年   2991篇
  1999年   2511篇
  1998年   2274篇
  1997年   2142篇
  1996年   1701篇
  1995年   1602篇
  1994年   1368篇
  1993年   1114篇
  1992年   1021篇
  1991年   860篇
  1990年   707篇
  1989年   645篇
  1988年   603篇
  1987年   525篇
  1986年   463篇
  1985年   646篇
  1984年   492篇
  1983年   310篇
  1982年   365篇
  1981年   292篇
  1980年   222篇
  1979年   194篇
  1978年   168篇
  1977年   112篇
  1976年   88篇
  1975年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
胸腰椎压缩性骨折的护理要点   总被引:2,自引:0,他引:2  
胸腰椎压缩性骨折的护理要点福建漳州市中医院(363000)郭燕玲,陈联源我院自1989年来对胸腰椎压缩性骨折实行辨证护理,收到满意效果,介绍如下。常规护理:屈曲型胸腰椎压缩性骨折,令病人仰卧在硬板床上,骨折处垫一软枕头,在耐受的情况下逐渐增加枕头高度...  相似文献   
32.
目的:探索地奥心血康(DAXXK)对急性心肌梗死(AMI)的疗效。方法:AMI病人89例,采用随机单盲法分为2组,DAXXK胶囊组45例,男性36例,女性9例,年龄59±s8a.采用DAXXK200mg,po,tid,共4wk。地尔硫组44例,男性34例,女性10例,年龄58±7a.采用盐酸地尔硫30mg,po,tid,共4wk。结果:DAXXK组治疗后心绞痛发作频率须静脉滴注硝酸甘油的量及镇痛药需用次数均显著低于对照组;心功能(SV,CO,LVEF,STI)改善亦显著优于对照组;心肌酶(GOT,CK,CK-MB,LDH)峰值,住院期间心力衰竭及心律失常发生率亦均显著低于对照组。结论:DAXXK是防治AMI有较好疗效的纯中药制剂。  相似文献   
33.
Summary— To investigate if the functional alterations observed in resistance arteries of spontaneously hypertensive rats (SHRs) were also present at the coronary level, in vitro experiments were performed in mesenteric resistance arteries (MRA) and in right (RIC) and left interventricular coronary (LIC) arteries taken from 15–25-week-old SHR and age-matched Wistar Kyoto rats WKYs. Using a passive extension protocol, internal diameters corresponding to 100 mmHg intraluminal pressure (D100) were determined and vessels were set up to a normalized internal diameter (0.9 D100). SHR mesenteric resistance arteries had a significantly smaller diameter compared to WKY arteries, whereas both types of SHR coronary arteries had a greater diameter compared to those of WKY rats. In arteries in the absence of contracting agonist, nitro-L-arginine (NOLA, 100 μM) induced a progressive rise in basal tone, which could be reversed by subsequent addition of L-arginine (100 μM) but not D-arginine (100 μM). When expressed as percent of maximal contractions induced by agonists (noradrenaline, NA [10 μM] in MRA; serotonin, 5-HT [10 μM], in RIC and LIC), these contractions were significantly stronger in WKY compared to SHR coronary and mesenteric resistance arteries. In NA-precontracted MRA and 5HT-precontracted coronary arteries in the presence of indomethacin (10 μM), the magnitude of acetylcholine-induced maximal relaxations (expressed as percent of maximal contractions induced by agonists) was greater in WKY compared to SHR arteries. After a 30-min incubation period, NOLA (100 μM) completely inhibited relaxations induced by acetylcholine (0.01–10 μM) in all types of precontracted arteries. Subsequent additions of sodium nitroprusside, (SNP, 10 μM) induced complete relaxations in all preparations. These results show that a basal release of NO or NO-like compound by endothelial cells is present in isolated mesenteric resistance and coronary arteries of WKY rats and SHRs. The contribution of endothelium-derived relaxing factor-nitric oxide (EDRF-NO) to arterial tone was lower in MRA compared to coronary arteries in both strains and in SHR compared to WKY arteries. In the SHR preparations, the impaired relaxation induced by acetylcholine appeared to be due to a functional alteration of the endothelium in the presence of normal reactivity of the smooth muscle cells.  相似文献   
34.
经结膜下穹隆至上颌窦插管术治疗泪道阻塞的临床研究   总被引:1,自引:0,他引:1  
采用经结膜囊下穹隆至上颌窦插管的术式引流泪液,治疗泪道阻塞引起的溢泪症,获得较为满意的效果。手术的主要步骤是:局麻后于结膜囊下穹隆内1/3区作一4mm长的结膜切口,自筋膜下分离至眶线下5mm。从切口伸入上颌窦骨钻钻通上颌窦顶壁,插入长短适度的义管,并向管内注入生理盐水,证实有液体流入鼻咽部后,固定义管。术后定期冲洗,无需拆线,应用这种术式治疗泪道阻塞引起的溢泪症218眼,其中溢泪完全消失151眼占82.1%,溢泪减轻的27眼占14.6%,总效率96.7%。  相似文献   
35.
The granulocyte colony-stimulating factor (G-CSF) has been shown to accelerate recovery from severe neutropenia and to decrease the incidence of documented infections after intensive chemotherapy in cancer patients. However, the routine prophylactic use of G-CSF is expensive. This study was conducted to determine the role of G-CSF as adjunct therapy for septicemia following neutropenia caused by chemotherapy in children with acute leukemia. Fifty consecutive episodes of septicemia were studied involving 34 episodes of Gram-negative, 7 episodes of Gram-positive, 5 episodes of polymicrobial bacterial septicemia, one episode of fungemia, and 3 episodes of disseminated fungal infection. In the first 25 episodes, G-CSF was not used (group A). For the next 16 episodes, G-CSF 200 μg per square meter per day subcutaneously was given immediately after the septicemia was documented until the absolute neutrophil count was maintained at more than 1,500 per cubic millimeter (group B). Thereafter, G-CSF at the same dose as that of group B was prophylactically used in all the children who received high-dose cytosine arablnc-side-containing regimens. Nine episodes of septicemia occurred (group C). The incidences of mortality per episode of septicemia in groups A, B, and C were 12.0% (3/25), 12.5% (2/16) and 0% (0/9), respectively. Statistically, there was no difference between the three groups overall and in pair-wise comparisons (all P > 0.5). The durations of G-CSF administration in group B ranged from 6 to 26 days with a median of 12 days and the durations of G-CSF administration in group C ranged from 10 to 23 days with a median of 19 days. With or without G-CSF, there may be no significant difference in the mortality of septicemia following neutropenia caused by chemotherapy in children with acute leukemia.  相似文献   
36.
Acute ischaemia of the vertebrobasilar circulation leads to a variety of clinical manifestation and is mostly due to cardiogenic or artery-to-artery embolism. We describe four neurological emergency situations involving vertebrobasilar artery aclusion of other origins: basilar migraine, extrinsic compression by rheumatoid inflammatory tissue, generalized vasculitis in subacute rheumatic fever and basilar artery dissection. The differential diagnosis of acute vertebrobasilar artery occlusion may have an important impact on patient management.  相似文献   
37.
A sample enriched for familial combined hyperlipidemia (FCHL) was examined for evidence of an association between genotype at an apolipoprotein B (apoB) elevating locus defined by complex segregation analysis and FCHL. Complex segregation analysis detected a locus with a large effect on plasma apoB levels and was used to compute the most probable genotype of family members. None of the 35 normolipidemic adults carried a copy of the allele associated with elevated apoB levels, yet 58% of the 109 adults with FCHL carried 1 (29%) or 2 (28%) copies. Two of 28 (7%) normal children had 1 copy of this allele and none had 2 copies, while 88 of 182 (48%) children with FCHL had 1 (26%) or 2 (22%) copies. Further, 4l of 48 (85%) individuals classified as having hyperapobetalipoproteinemia did not carry a copy of this “elevated apoB” allele. Therefore, the presence of the allele associated with elevation of apoB level is highly predictive of FCHL and this association cannot be explained solely by the presence of elevated apoB levels in FCHL, suggesting that the locus controlling apoB levels may play an etiologic role in FCHL. © 1993 Wiley-Liss, Inc.  相似文献   
38.
1. In chloralose-urethane anaesthetized cats, the dorsal cardiovascular reactive area (DCRA) in the parvocellular reticular nucleus dorsomedial to the facial nucleus, and the ventral cardiovascular reactive area (VCRA) ventromedial to the facial nucleus, were stimulated by microinjections of sodium glutamate (100–200 nmol) or electric current. 2. Stimulation of DCRA, with a long latency of 15–20 s, elicited a marked increase of blood flow in the contralateral femoral artery with little change to moderate increase in systemic arterial blood pressure (ABP). In the relatively dorsal portion of DCRA, however, a smaller increase of blood flow in the ipsilateral femoral artery was elicited. 3. On the other hand, stimulation of VCRA with a short latency (3–5 s) evoked an increase of blood flow in both femoral arteries which was more prominent on the contralateral side. The responses were accompanied with decreases in the blood flow of other vascular beds with only a slight increase or minimal change in ABP. 4. The data suggest that DCRA and VCRA are both viscerotopically organized to alter the resistance of individual vascular beds for redistribution of blood flow.  相似文献   
39.
1. Endothelium-dependent relaxation in response to acetylcholine (ACh) and the calcium ionophore A 23187 was examined in aorta, coronary, basilar and renal arteries isolated from Watanabe heritable hyperlipidaemic (WHHL) rabbits of 2, 6 and 12 months of age, with normolipidaemic heterozygous WHHL rabbits as controls. 2. In the rings of WHHL rabbit aortae and coronary arteries preconstricted with vasoconstrictors, endothelium-dependent relaxation in response to ACh was attenuated with age compared to the heterozygous WHHL rabbits. A significant negative correlation was found between the total cholesterol content and the relaxation response to ACh in the aortae or coronary arteries from 6 and 12 month old WHHL rabbits. 3. In the rings of basilar arteries, endothelium-dependent relaxations to ACh were not modified with age. Similarly, in the rings of renal arteries, the relaxation response to ACh was not changed with age, but in the 6 and 12 month preparations, after the age of 6 months, a contraction following the relaxation appeared at higher concentrations of ACh (10?7 to 10?6 mol/L). The contraction was endothelium-dependent and inhibited by indomethacin. 4. A 23187-induced endothelium-dependent relaxations were also markedly attenuated in the aorta and significantly in the coronary artery with age. 5. Endothelium-independent relaxation to sodium nitroprusside was not changed in all arteries from WHHL rabbits of different ages. 6. These findings indicate that in the aorta and coronary artery of the WHHL rabbit, the endothelium-dependent relaxation to ACh and A 23187 becomes impaired with increasing age (i.e., with the progression of cholesterol deposition in the arterial wall) but is preserved in the basilar and renal artery.  相似文献   
40.
1. Global myocariial ischaemia (MI) for periods greater tan 5 min caused an inhibition of phosphatidylinositol specific phospholipase C (PtdIns-PLC) activity. 2. Two min reperfusion following a 20 min MI period, a time point associated with reperfusion-induced arrhythmias, resulted in an activation of PtdIns-PLC activity, dependent on endogenous noradrenaline and mediated via al-adrenoceptors. 3. This 2 min reperfusion response, in contrast to healthy myocardium, resulted in: (i) enhanced PtdIns-PLC activity; (ii) increased sensitivity to endogenous noradrenaline; (iii) rapid increases in inositol(1,4,5)trisphosphate (Ins(1,4,5)P3); and (iv) PLC hydrolysis primarily of PtdIns(4,5)P2, such that the majority of InsP isomers derive from Ins(1,4,5)P3. 4. Together, these data suggest a functional role for Ins(1,4,5)P3 under postischaemic reperfusion conditions, and provide a possible link between al-adrenoceptor stimulation of the PtdIns turnover pathway and reperfusion injury.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号