全文获取类型
收费全文 | 51565篇 |
免费 | 3130篇 |
国内免费 | 2689篇 |
专业分类
耳鼻咽喉 | 89篇 |
儿科学 | 1139篇 |
妇产科学 | 725篇 |
基础医学 | 3605篇 |
口腔科学 | 312篇 |
临床医学 | 5122篇 |
内科学 | 12266篇 |
皮肤病学 | 59篇 |
神经病学 | 2178篇 |
特种医学 | 1195篇 |
外科学 | 3538篇 |
综合类 | 12480篇 |
现状与发展 | 5篇 |
预防医学 | 2698篇 |
眼科学 | 865篇 |
药学 | 7708篇 |
28篇 | |
中国医学 | 3054篇 |
肿瘤学 | 318篇 |
出版年
2024年 | 76篇 |
2023年 | 559篇 |
2022年 | 980篇 |
2021年 | 1455篇 |
2020年 | 1531篇 |
2019年 | 1317篇 |
2018年 | 1338篇 |
2017年 | 1446篇 |
2016年 | 1587篇 |
2015年 | 1565篇 |
2014年 | 3164篇 |
2013年 | 4217篇 |
2012年 | 2848篇 |
2011年 | 3071篇 |
2010年 | 2595篇 |
2009年 | 2418篇 |
2008年 | 2462篇 |
2007年 | 2663篇 |
2006年 | 2410篇 |
2005年 | 2025篇 |
2004年 | 1841篇 |
2003年 | 1794篇 |
2002年 | 1474篇 |
2001年 | 1395篇 |
2000年 | 1161篇 |
1999年 | 951篇 |
1998年 | 822篇 |
1997年 | 855篇 |
1996年 | 745篇 |
1995年 | 769篇 |
1994年 | 648篇 |
1993年 | 480篇 |
1992年 | 515篇 |
1991年 | 456篇 |
1990年 | 375篇 |
1989年 | 324篇 |
1988年 | 331篇 |
1987年 | 257篇 |
1986年 | 240篇 |
1985年 | 379篇 |
1984年 | 340篇 |
1983年 | 216篇 |
1982年 | 262篇 |
1981年 | 234篇 |
1980年 | 224篇 |
1979年 | 130篇 |
1978年 | 104篇 |
1977年 | 98篇 |
1976年 | 85篇 |
1973年 | 42篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Chronic food restriction has been shown to enhance glucose metabolism in adipocytes from lean Zucker rats at 10, 26, and 52 weeks of age compared to ad libitum-fed lean rats. Only adipocytes from food restricted 10-week-old obese rats demonstrated this response. In this study, lean and obese rats were food restricted from 5 until 14 weeks of age to determine the age at which adipocytes from obese rats were no longer affected by this intervention. Effects of 1 week of refeeding were also determined. When the rats were killed, body weights were highest in control rats followed by restricted/refed and then restricted rats within each genotype. Epididymal pad weights of lean rats were resistant to dietary intervention, while those of obese-restricted and obese-restricted/refed rats weighed less than pads of obese-control rats. Retroperitoneal pad weight was lowered by food restriction in both genotypes; but only that of lean-restricted/refed rats totally recovered with refeeding. Adipocytes of lean-restricted rats had the highest conversion of glucose to CO2. Glyceride-glycerol production was higher in obese compared to lean rats, but restricted rats had elevated conversion of glucose to fatty acids. In general, these results indicate that by 14 weeks of age obese Zucker rats no longer respond to food restriction with an elevated rate of glucose metabolism in adipocytes. 相似文献
42.
ABSTRACT A follow-up examination was performed one month to 20 years after adrenalectomy in 28 cases with surgically treated primary aldosteronism due to adrenal adenoma. The mean age at diagnosis was 45, and the mean duration of hypertension seven years. Severe hypertension with a diastolic blood pressure of 130 mmHg or more was observed in 35%. Postoperatively cerebrovascular catastrophe developed in two cases, both of which belonged to the group of patients with severe hypertension. Normalization of blood pressure was observed in 70% and in the remaining subjects the blood pressure was lower than at diagnosis. The blood pressure response to adrenalectomy appeared unpredictable in view of such parameters as the initial blood pressure, age at diagnosis, and duration of the hypertensive state. Toxicosis during pregnancy and metrorrhagia was observed with unexpectedly high frequency in this study population. Low ambulatory plasma renin activity was recorded at the follow-up in 15 out of 18 subjects studied in the absence of evidence of hyperaldosteronism. 相似文献
43.
Paradoxical hypertension is a relatively common complication of surgical repair of coarctation of the aorta. An early phase of systolic hypertension has been ascribed to elevated levels of norepinephrine. Activation of the renin-angiotensin system from sympathetic stimulation has been implicated in a later phase of systolic and diastolic hypertension that can result in mesenteric arteritis. The use of a rapidly acting, titratable intravenous alpha- and beta-adrenergic blocker, such as labetalol hydrochloride, addresses both of these neurohormonal mechanisms. In the intravenous form, it would appear to be an excellent choice for the management of early postoperative hypertension and it can be converted to the oral form in cases of persistent hypertension. We report for the first time the use of labetalol in two young patients for the control of paradoxical hypertension following coarctation repair. 相似文献
44.
穹隆-海马伞切断对大鼠脑内TrkA表达的影响 总被引:1,自引:0,他引:1
①目的 探讨穹隆 海马伞切断对大鼠脑内不同部位神经生长因子受体TrkA表达的影响及临床意义。②方法 成年健康雌性Wistar大鼠 10只 ,随机分为穹隆 海马伞切断模型组和假手术组。两组大鼠均常规取海马CA1区、皮质区、杏仁复合体区、基底前脑Meynert核等部位脑组织与假手术组比较TrkA阳性细胞表达情况。③结果 假手术组大脑各观察区有基础水平的TrkA表达。模型组大脑海马CA1区、大脑皮质区、杏仁复合体区以及Meynert核区TrkA阳性细胞数明显减少 (t=3.94 4~ 8.4 4 2 ,P <0 .0 5 )。 ④结论 穹隆 海马伞切断可致大鼠脑内多部位TrkA表达减少 ,其可能是导致认知和情绪损伤的原因之一。 相似文献
45.
L Madacsy A Yasar T Tulassay A Körner J Kelemen M Hóbor M Miltényi 《Acta paediatrica (Oslo, Norway : 1992)》1994,83(4):414-417
Twenty-four-hour blood pressure and heart rate measurements were carried out in 14 newly diagnosed diabetics and in 28 diabetics with 5–13 years' duration of the disease; 8 healthy children were used as controls. Mean arterial blood pressure increased at night in 5, decreased slightly (less than 10%) in 5 and decreased markedly (more than 10%) in 18 diabetics with longer duration of the disease. The diurnal-nocturnal differences in heart rates were significantly lower in diabetics with relative "nocturnal hypertension" compared to the control group ( p < 0.05). A significant negative correlation was found between maximal arterial blood pressure during physical exercise and the diurnal-nocturnal differences in mean arterial blood pressure in diabetics ( r =−0.58; p < 0.02). In conclusion, we found elevated nocturnal blood pressure in a subgroup of children with longer duration of diabetes and without increased albumin excretion. However, longitudinal studies of blood pressure profiles are needed to identify the candidates for diabetic vasculopathy among diabetic children. 相似文献
46.
47.
11例TH胶胃冠状静脉栓塞术临床治疗结果表明:(1)11例中的4例急性上消化道大出血患者均在12h左右出血基本停止,随访近一年未再发生出血现象。(2)10例半年后复查肝功能均有不同程度改善。(3)一年后复查食道钡餐透视X线平片发现8例患者食道静脉曲张有不同程度减轻。(4)11例中1例因术中急性肝功能衰竭死亡。因此我们认为此术式操作简便,手术创伤小、较易推广,是治疗门脉高压症合并食管胃底静脉曲张出血的一种有效方法。 相似文献
48.
T. Terada K. Miyamoto G. Hyotani M. Tsuura Y. Nakamura T. Nishiguchi T. Itakura S. Hayashi N. Komai 《Acta neurochirurgica》1992,118(3-4):108-111
Summary Changes in tumour blood flow under an induced hypertensive state were examined in malignant brain tumours to know if the precondition for the effectiveness of induced hypertensive chemotherapy — relative increase in tumour blood flow — are fulfilled. Tumour blood flow was measured under both a resting and an induced hypertensive state in 12 patients with various malignant brain tumours (6 gliomas, 6 metastatic brain tumours) using xenon-enhanced computed tomography. The blood pressure was elevated 40% above the systemic blood pressure of the resting state by the infusion of angiotensin II. Tumour blood flow increased 30% on average above the normal brain tissue blood flow after the induction of an induced hypertensive state (p < 0.05). The tumour blood flow increased in 11 cases of malignant tumours, but decreased in one case with massive brain oedema after induced hypertension. The increase in blood flow was higher in hypervascular tumours and less in hypovascular tumours. Therefore, induced hypertensive chemotherapy probably will be more effective in hypervascular malignant brain tumours with small mass effects. 相似文献
49.
50.
Evaluation of renal first pass blood flow with a functional image technique in hypertensive patients
Masatoshi Ishibashi Seiichiro Morita Noriyoshi Umezaki Hisashi Ohtake 《European journal of nuclear medicine and molecular imaging》1988,14(1):25-27
The renal circulation of patients with essential hypertension and renovascular hypertension was evaluated using 99mTc-DTPA. The first renal peak count (the first Cmax; FCmax), time phase distribution (the first Tmax; FTmax), and blood velocity (the FCmax/FTmax) were calculated by digital imaging. This yields a visual image of the renal circulation. We consider that the increase in the renal first pass blood flow in patients with essential hypertension is best observed pixel by pixel. The FCmax and FCmax/FTmax images before and after treatment by percutaneous transluminal renal angioplasty in patients with renovascular hypertension clearly show its therapeutic effect. The FI technique, therefore, has the advantage that it can be performed at the same time as the conventional routine examinations of renal function. This makes it very useful clinically. 相似文献