全文获取类型
收费全文 | 1924篇 |
免费 | 135篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 123篇 |
妇产科学 | 21篇 |
基础医学 | 255篇 |
口腔科学 | 35篇 |
临床医学 | 205篇 |
内科学 | 466篇 |
皮肤病学 | 32篇 |
神经病学 | 93篇 |
特种医学 | 325篇 |
外科学 | 122篇 |
综合类 | 15篇 |
一般理论 | 2篇 |
预防医学 | 155篇 |
眼科学 | 7篇 |
药学 | 68篇 |
肿瘤学 | 131篇 |
出版年
2023年 | 5篇 |
2021年 | 18篇 |
2020年 | 11篇 |
2019年 | 15篇 |
2018年 | 29篇 |
2017年 | 19篇 |
2016年 | 18篇 |
2015年 | 36篇 |
2014年 | 33篇 |
2013年 | 47篇 |
2012年 | 52篇 |
2011年 | 60篇 |
2010年 | 46篇 |
2009年 | 54篇 |
2008年 | 53篇 |
2007年 | 71篇 |
2006年 | 52篇 |
2005年 | 64篇 |
2004年 | 55篇 |
2003年 | 49篇 |
2002年 | 55篇 |
2001年 | 50篇 |
2000年 | 28篇 |
1999年 | 44篇 |
1998年 | 108篇 |
1997年 | 76篇 |
1996年 | 84篇 |
1995年 | 61篇 |
1994年 | 68篇 |
1993年 | 72篇 |
1992年 | 50篇 |
1991年 | 32篇 |
1990年 | 38篇 |
1989年 | 63篇 |
1988年 | 48篇 |
1987年 | 63篇 |
1986年 | 46篇 |
1985年 | 48篇 |
1984年 | 39篇 |
1983年 | 28篇 |
1982年 | 31篇 |
1981年 | 25篇 |
1980年 | 32篇 |
1979年 | 8篇 |
1978年 | 17篇 |
1977年 | 18篇 |
1976年 | 21篇 |
1975年 | 14篇 |
1970年 | 2篇 |
1932年 | 3篇 |
排序方式: 共有2070条查询结果,搜索用时 0 毫秒
91.
JR Skinner AG Stuart J O'Sullivan A Heads RJ Boys S Hunter 《Archives of disease in childhood》1993,69(2):216-220
Doppler and direct measurements of right ventricle to right atrial pressure drop were made during cardiac catheterisation on 28 occasions in 26 infants with congenital heart disease. Age was 10 days to 12 months (median 4.5 months), and weight was 3.1 to 9.0 kg (median 4.7 kg). We measured peak velocity of tricuspid regurgitation by continuous wave Doppler, and the pressure drop was calculated using the modified Bernoulli equation (delta p = 4v2). There was a high correlation (r = 0.95) between direct and Doppler measurements. Doppler values tended to underestimate the right ventricle to right atrial pressure drop, but this was not of clinical significance (mean 2 mm Hg). The 95% confidence interval for the Doppler velocity was -0.41 to +0.26 m/sec, and was consistent across the range of pressures studied. Variability between observers was tested, by two observers performing sequential paired examinations on 16 newborn babies with tricuspid regurgitation. The coefficient of repeatability was 6.3 mm Hg (95% confidence interval 4.7 to 9.5 mm Hg) or 0.26 m/sec (0.18 to 0.50 m/sec). This method of right ventricular pressure estimation, validated previously only in older children and adults, is a reproducible and accurate technique in infants with tricuspid regurgitation. 相似文献
92.
A O'Meara W Tormey RJ FitzGerald M Fitzgibbon D Kenny 《Acta paediatrica (Oslo, Norway : 1992)》1994,83(1):88-92
O'Meara A, Tormey W, Fitz Gerald RJ, Fitzgibbon M, Kenny D. Interpretation of random urinary catecholamines and their metabolites in neuroblastoma. Acta Paediatr 1994;83:88–92. Stockholm. ISSN 0803–5253
This study reports experience in the estimation of urinary catecholamines (uCATs) and their metabolites in the diagnosis and follow-up of neuroblastoma. Random urine samples were assayed for dopamine, noradrenaline and adrenaline, together with their metabolites 4-hydroxy 3-methoxyman-delic acid (HMMA) and homovanillic acid (HVA), using HPLC with electrochemical detection. Twenty of 21 patients had elevation of one or more uCATs metabolites at diagnosis. Patients were monitored serially from diagnosis and, in those patients who had delayed resection of primary tumour (n=13), particular attention was paid to levels at the pre-surgical evaluation as an indicator of persistence of viable disease at the time of surgery; dopamine proved to be the most accurate indicator of persistent disease at this time. Five of these patients developed recurrent disease, 4 of whom had elevation of two or more uCATs metabolites at the time of relapse. Several conclusions can be drawn from this study: (a) results for HMMA, HVA and dopamine in random urine samples will detect all but the most biochemically immature or inert tumours; (b) dopamine may be the most reliable indicator of persistent disease and (c) noradrenaline and adrenaline measurements were of little benefit. As results are Expressed in relation to urinary creatinine, excretion of which may be affected by dietary protein and is therefore not constant, borderline results should be repeated. 相似文献
This study reports experience in the estimation of urinary catecholamines (uCATs) and their metabolites in the diagnosis and follow-up of neuroblastoma. Random urine samples were assayed for dopamine, noradrenaline and adrenaline, together with their metabolites 4-hydroxy 3-methoxyman-delic acid (HMMA) and homovanillic acid (HVA), using HPLC with electrochemical detection. Twenty of 21 patients had elevation of one or more uCATs metabolites at diagnosis. Patients were monitored serially from diagnosis and, in those patients who had delayed resection of primary tumour (n=13), particular attention was paid to levels at the pre-surgical evaluation as an indicator of persistence of viable disease at the time of surgery; dopamine proved to be the most accurate indicator of persistent disease at this time. Five of these patients developed recurrent disease, 4 of whom had elevation of two or more uCATs metabolites at the time of relapse. Several conclusions can be drawn from this study: (a) results for HMMA, HVA and dopamine in random urine samples will detect all but the most biochemically immature or inert tumours; (b) dopamine may be the most reliable indicator of persistent disease and (c) noradrenaline and adrenaline measurements were of little benefit. As results are Expressed in relation to urinary creatinine, excretion of which may be affected by dietary protein and is therefore not constant, borderline results should be repeated. 相似文献
93.
A 4 year old girl treated with a standard chemotherapy protocol for acute lymphoblastic leukaemia developed hepatic candidosis during the consolidation phase. This relapsed after a prolonged course of amphotericin B and flucytosine. An eight week course of liposomal amphotericin produced a marked clinical improvement which was sustained for one year. A subsequent relapse was associated with transformation to myelodysplastic leukaemia. 相似文献
94.
It is imperative to know the details of the anatomy of the nose before understanding any surgical procedure performed on the nose. The details presented in this article should help the experienced and the novice surgeon accomplish the difficult task of a rhinoplasty. 相似文献
95.
Persoons JH Sutorius FJ Koopman RJ Schaafsma MR van Doorn GA 《American journal of obstetrics and gynecology》1999,180(4):1041-1044
Nodular cutaneous amyloidosis of the vulva is a rare phenomenon. We describe a patient with localized nodular lesions on the vulva that mimicked kissing ulcers such as are seen with vulvar carcinoma. These lesions were a result of multiple myeloma with subsequent primary systemic amyloidosis. The patient died of cardiac and renal decompensation 2 months after diagnosis. 相似文献
96.
Expression screening for genes preferentially expressed in mouse fetal ovaries relative to testes identified Cav-1 as a candidate female-specific gene. Cav-1 encodes caveolin-1, a component of the cell membrane invaginations known as caveolae, which are involved in lipid regulation and signal transduction. In situ hybridization revealed high levels of Cav-1 mRNA in developing ovaries, compared with moderate or low levels in testes. Analysis of caveolin-1 protein distribution by immunofluorescence showed this difference to be due to the development of a dense and complex vascular network in the developing ovary. These observations point to a higher degree of differentiation and organization of the early stage mammalian ovary than previously suspected. 相似文献
97.
98.
99.
SM Dyer IS de la Lande DB Frewin & RJ Head 《Clinical and experimental pharmacology & physiology》1998,25(3-4):246-251
1. 5-Hydroxytryptamine (5-HT) exerts both contractile and relaxant effects in the marmoset isolated aorta, actions that are unaffected by the 5-HT2 antagonist ketanserin. The aim of the present study was to define the receptors mediating the contractile activity of 5-HT in the marmoset aorta.
2. Contractile responses were elicited in aortic rings that were either: (i) precontracted submaximally with the thromboxane A2 agonist U44069 in order to amplify the responses; or (ii) exposed to N ω -nitro- L -arginine (100 μmol/L) plus LY 53857 (0.1 μmol/L; a 5-HT2 receptor antagonist shown previously to inhibit relaxation). The effect of 5-HT on adenosine 3',5'-cyclic monophosphate (cAMP) formation was also investigated.
3. The effects of agonists and antagonists comprised: (i) agonist potencies in the order 5-carboxamidotryptamine > 5-HT > sumatriptan > 8-hydroxy-2-(di- n -propylamino)tetralin; (ii) inhibition of contractile action of 5-HT by the 5-HT1D antagonist GR 127935; (iii) a contractile response to methysergide; (iv) a lack of effect of tropisetron, an antagonist of 5-HT3 and 5-HT4 receptors; and (v) inhibition of forskolin-stimulated cAMP formation by 5-HT (in the presence of LY 53857), indicative of negative coupling to adenylate cyclase.
4. The above effects fulfil the criteria for a 5-HT1 -like receptor. In view of the previous finding that this contractile response is insensitive to ketanserin, it is concluded that the contractile effects of 5-HT in the marmoset aorta are mediated exclusively by a 5-HT1 -like receptor. 相似文献
2. Contractile responses were elicited in aortic rings that were either: (i) precontracted submaximally with the thromboxane A
3. The effects of agonists and antagonists comprised: (i) agonist potencies in the order 5-carboxamidotryptamine > 5-HT > sumatriptan > 8-hydroxy-2-(di- n -propylamino)tetralin; (ii) inhibition of contractile action of 5-HT by the 5-HT
4. The above effects fulfil the criteria for a 5-HT
100.
This study examined relationships between dissociative symptoms experienced in the immediate aftermath of the Oakland/Berkeley firestorm and contact with the fire, life events, demographic variables, and actions taken after learning about the fire. One hundred eighty-seven participants completed self-report measures about their experiences during and immediately following the fire. Dissociative symptoms were significantly related to contact with the fire, sex, and stressful life events. Also, dissociative symptoms were significantly related to engaging in certain activities, such as trying to get closer to the fire and going into blocked-off areas and crossing police barricades. These results suggest that dissociative symptoms may merit special attention in intervention focusing on the immediate aftermath of disaster. 相似文献