全文获取类型
收费全文 | 423424篇 |
免费 | 34162篇 |
国内免费 | 11464篇 |
专业分类
耳鼻咽喉 | 4519篇 |
儿科学 | 11448篇 |
妇产科学 | 5063篇 |
基础医学 | 35606篇 |
口腔科学 | 11567篇 |
临床医学 | 42281篇 |
内科学 | 74531篇 |
皮肤病学 | 5104篇 |
神经病学 | 35822篇 |
特种医学 | 12132篇 |
外国民族医学 | 16篇 |
外科学 | 37115篇 |
综合类 | 62052篇 |
现状与发展 | 36篇 |
一般理论 | 32篇 |
预防医学 | 45254篇 |
眼科学 | 4317篇 |
药学 | 34768篇 |
518篇 | |
中国医学 | 34127篇 |
肿瘤学 | 12742篇 |
出版年
2024年 | 1573篇 |
2023年 | 8656篇 |
2022年 | 15843篇 |
2021年 | 21468篇 |
2020年 | 20559篇 |
2019年 | 19467篇 |
2018年 | 17968篇 |
2017年 | 16433篇 |
2016年 | 15838篇 |
2015年 | 15062篇 |
2014年 | 28967篇 |
2013年 | 30842篇 |
2012年 | 24715篇 |
2011年 | 26684篇 |
2010年 | 21355篇 |
2009年 | 19521篇 |
2008年 | 18923篇 |
2007年 | 18689篇 |
2006年 | 16368篇 |
2005年 | 13630篇 |
2004年 | 11469篇 |
2003年 | 10002篇 |
2002年 | 8091篇 |
2001年 | 6920篇 |
2000年 | 5917篇 |
1999年 | 4948篇 |
1998年 | 4424篇 |
1997年 | 3947篇 |
1996年 | 3388篇 |
1995年 | 3113篇 |
1994年 | 2874篇 |
1993年 | 2492篇 |
1992年 | 2363篇 |
1991年 | 2100篇 |
1990年 | 1734篇 |
1989年 | 1557篇 |
1988年 | 1441篇 |
1987年 | 1305篇 |
1986年 | 1159篇 |
1985年 | 2498篇 |
1984年 | 2659篇 |
1983年 | 1657篇 |
1982年 | 2150篇 |
1981年 | 1548篇 |
1980年 | 1292篇 |
1979年 | 1151篇 |
1978年 | 926篇 |
1977年 | 717篇 |
1976年 | 833篇 |
1975年 | 533篇 |
排序方式: 共有10000条查询结果,搜索用时 57 毫秒
61.
62.
L. C. Scott G. K. Wright G. S. Rai A. N. Exton-Smith J. M. Gardiner 《International journal of geriatric psychiatry》1991,6(8):583-588
Memory performance of elderly patients in the early stages of Alzheimer's disease (DAT) was compared with that of elderly control subjects. In explicit tests of recognition memory, which involve conscious recollection, the DAT patients were grossly impaired. In implicit tests of anagram solution and wordstem completion, which do not require conscious recollection, the DAT patients were not impaired. These findings further support the idea that a separate memory system, episodic memory, underlies conscious recollection, that it is this system which is most commonly damaged in amnesia, and that memory systems not involving conscious recollection may be spared in the early stages of Alzheimer's disease. 相似文献
63.
目的 探讨老年人急性阑尾炎的临床特点,更好地把握腹腔镜阑尾切除(LA)术的方法和特点。方法 回顾分析50例老年人急性阑尾炎LA的临床资料。结果 LA均获成功,患者全部治愈,无严重的并发症发生,肠功能恢复时间及住院时间均缩短。结论 老年人反应迟钝,阑尾炎进展快,易发生坏疽及穿孔,合并症多,手术风险较高,LA是安全、可行的,除个别腹膜后阑尾炎外,其余均可施行LA。 相似文献
64.
Borras Merce; Valdivielso Jose M.; Egido Ramon; Vicente de Vera Pilar; Bordalba Josep Ramon; Fernandez Elvira 《Nephrology, dialysis, transplantation》2006,21(3):789-791
65.
66.
The goal of the present study is to develop a technique for laparoscopic aortobifemoral bypass.Piglets weighing between 60 and 78 kg were anesthetized with halothane. The lateral retroperitoneal approach was preferred to the more familiar anterior transperitoneal approach and was successfully completed in 19 piglets. The piglets were placed in the right lateral decubitus position. The first port (2 cm) was inserted halfway between the tip of the 12th rib and the iliac crest. Four other trocars were placed in the retroperitoneum after balloon inflation had allowed creation of a space which permitted visualization of the aorta from the left renal artery down to the aorto-iliac junction. After evacuation of the retropneumoperitoneum, the cavity was maintained using an abdominal lift device and a retractor.Using this approach, we performed four aortobifemoral bypasses (end-to-end aortic anastomosis) after conventional intravenous heparinization (100 IU/kg) in less than 4 h. Blood loss did not exceed 250 ml and the hematocrit remained stable. Postmortem evaluation of the grafts revealed they were positioned as in a conventional bypass, their limbs having followed in the created retroperitoneal tunnels along the path of the native arteries. No mortality occurred before sacrifice of the animals. We believe that this first performed series of totally retroperitoneal laparoscopic aortobifemoral bypasses in the porcine model is useful in preparation for human application due to the anatomical similarities in the periaortic region. 相似文献
67.
H. S. Markus A. M. Tomkins G. M. Stern 《Journal of neural transmission (Vienna, Austria : 1996)》1993,5(2):117-125
Summary An anthropometric study was performed in 95 subjects (53 male, 42 female) with Parkinson's disease. Weight, height, triceps and biceps skin-fold thicknesses, and mid-arm circumference were recorded. A high incidence of undernutrition was found (23.6% of males and 22.5% of females, as defined by recent British guidelines). A subgroup of severely disabled patients with Parkinson's disease had a significantly lower mean body mass index than a similarly disabled control group with chronic pyramidal upper motor neuron lesions (males 20.6v 23.2 kg/m2 p<0.05; females 20.6v 26.6 kg/m2 p<0.01), suggesting that the undernutrition is not due to chronic illness or immobility alone. Correlation between anthropometric indices and clinical features of disease demonstrated that the presence of moderate or severe dyskinetic movements was the clinical parameter most strongly related to undernutrition. The reduction in anthropometric indices was most marked for skin fold thickness (related to percentage body fat) and least for arm muscle circumference (related to lean body mass); therefore the weight loss seen in Parkinson's disease is primarily due to fat loss rather than muscle loss. 相似文献
68.
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
69.
70.
Rh血型不合新生儿溶血病检测方法及应用 总被引:3,自引:0,他引:3
产前检测Rh,D因子及抗人球蛋白(coombs)试验是必要的。测定Rh,D因子及抗D滴度使用木瓜酶方法。通过对11261例孕妇常规检查Rh,D因子,发现D阴性74例。Rh,D阴性妇女占6.5‰。22例Rh,D阴性的孕妇所分娩的新生儿均为Rh,D阳性。其中2例孕妇血清抗D滴度为1∶32,病情严重,宫内输血无效,胎死宫内。初产妇13例,占59%。活产20例,存活率90%。Rh因子及抗人球蛋白试验方法简便、易行,一般医院均可进行。对有流产史、输血史的孕妇检查Rh因子是十分必要的。在有条件的医院,对Rh,D阴性的产妇分娩Rh,D阳性的新生儿之后,产妇应预防性注射抗D免疫球蛋白 相似文献