全文获取类型
收费全文 | 35722篇 |
免费 | 2656篇 |
国内免费 | 1546篇 |
专业分类
耳鼻咽喉 | 89篇 |
儿科学 | 592篇 |
妇产科学 | 264篇 |
基础医学 | 3914篇 |
口腔科学 | 1152篇 |
临床医学 | 2581篇 |
内科学 | 6032篇 |
皮肤病学 | 309篇 |
神经病学 | 3659篇 |
特种医学 | 954篇 |
外国民族医学 | 3篇 |
外科学 | 2971篇 |
综合类 | 4474篇 |
现状与发展 | 5篇 |
预防医学 | 2344篇 |
眼科学 | 316篇 |
药学 | 7236篇 |
11篇 | |
中国医学 | 1831篇 |
肿瘤学 | 1187篇 |
出版年
2024年 | 116篇 |
2023年 | 552篇 |
2022年 | 1118篇 |
2021年 | 1460篇 |
2020年 | 1060篇 |
2019年 | 933篇 |
2018年 | 986篇 |
2017年 | 967篇 |
2016年 | 1029篇 |
2015年 | 1140篇 |
2014年 | 1777篇 |
2013年 | 2470篇 |
2012年 | 1736篇 |
2011年 | 1643篇 |
2010年 | 1494篇 |
2009年 | 1401篇 |
2008年 | 1449篇 |
2007年 | 1398篇 |
2006年 | 1359篇 |
2005年 | 1248篇 |
2004年 | 1080篇 |
2003年 | 1019篇 |
2002年 | 956篇 |
2001年 | 929篇 |
2000年 | 818篇 |
1999年 | 711篇 |
1998年 | 702篇 |
1997年 | 776篇 |
1996年 | 675篇 |
1995年 | 591篇 |
1994年 | 553篇 |
1993年 | 462篇 |
1992年 | 487篇 |
1991年 | 455篇 |
1990年 | 404篇 |
1989年 | 401篇 |
1988年 | 366篇 |
1987年 | 326篇 |
1986年 | 288篇 |
1985年 | 384篇 |
1984年 | 373篇 |
1983年 | 236篇 |
1982年 | 262篇 |
1981年 | 237篇 |
1980年 | 199篇 |
1979年 | 181篇 |
1978年 | 154篇 |
1977年 | 129篇 |
1976年 | 119篇 |
1975年 | 93篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
Kim Hahn Le Quan Sang Jean-Luc Elghozi Philippe Meyer Marie-Aude Devynck 《Clinical and experimental pharmacology & physiology》1987,14(3):187-189
1. Plasma renin activity (PRA) and platelet cytosolic free calcium concentration ([Ca2+]i) were simultaneously determined in 18 untreated essential hypertensive subjects and 17 normotensive controls. A significant positive correlation was found between [Ca2+]i and PRA (slope = 42 nmol/l/ng/ml/h) in these 35 subjects. 2. Two determinations more than one week apart in nine subjects confirmed the parallel fluctuations of [Ca2+]i and PRA. A strict sodium restriction produced a progressive PRA elevation associated with a parallel rise in [Ca2+]i in one subject. 3. These results are consistent with the hypothesis that angiotensin II causes a concentration-dependent calcium mobilization. 相似文献
92.
Cleide G. da Silva Ana Rúbia F. Bueno Patrícia F. Schuck Guilhian Leipnitz Csar A. J. Ribeiro Clvis M. D. Wannmacher Angela T. S. Wyse Moacir Wajner 《International journal of developmental neuroscience》2003,21(4):217-224
L-2-Hydroxyglutaric acid (LGA) is the biochemical hallmark of patients affected by the neurometabolic disorder known as L-2-hydroxyglutaric aciduria (LHGA). Although this disorder is predominantly characterized by severe neurological findings and pronounced cerebellum atrophy, the neurotoxic mechanisms of brain injury are virtually unknown. In the present study, we investigated the effect of LGA, at 0.25-5mM concentrations, on total creatine kinase (tCK) activity from cerebellum, cerebral cortex, cardiac muscle and skeletal muscle homogenates of 30-day-old Wistar rats. CK activity was measured also in the cytosolic (Cy-CK) and mitochondrial (Mi-CK) fractions from cerebellum. We verified that tCK activity was significantly inhibited by LGA in the cerebellum, but not in cerebral cortex, cardiac muscle and skeletal muscle. Furthermore, CK activity from the mitochondrial fraction was inhibited by LGA, whereas that from the cytosolic fraction of cerebellum was not affected by the acid. Kinetic studies revealed that the inhibitory effect of LGA on Mi-CK was non-competitive in relation to phosphocreatine. Finally, we verified that the inhibitory effect of LGA on tCK was fully prevented by pre-incubation of the homogenates with reduced glutathione (GSH), suggesting that this inhibition is possibly mediated by oxidation of essential thiol groups of the enzyme. Considering the importance of creatine kinase activity for energy homeostasis, our results suggest that the selective inhibition of this enzyme activity by increased levels of LGA could be possibly related to the cerebellar degeneration characteristically found in patients affected by L-2-hydroxyglutaric aciduria. 相似文献
93.
将32例肝脏外科疾病患者随机分为Ⅰ组(单能源TPN组10例);Ⅱ组(双能源TPN组11例,其中脂肪乳剂用量为1g·kg-1·d-1);Ⅲ组(双能,TPN组11例,其中脂肪乳剂用量为2g·kg-1·d-1)。术后按组别给予TPN支持共6天,术前1天、术后第1和第6天测定肝功,糖代谢及蛋白质合成代谢指标。结果:①Ⅱ、Ⅲ组术后第6天肝脏酶学指标明显下降(P<0.05),而Ⅰ组仍高于术前水平(P<O.05);②Ⅱ、Ⅲ组术后糖代谢基本恢复正常,而Ⅰ组出现高血糖症及高胰岛素血症(P<0.05);③Ⅱ组肝脏蛋白质合成水平恢复术前水平或略有提高(P<0.05),而Ⅰ和Ⅲ组术后蛋白质合成功能仍低(P<0.05)。结果提示:含脂肪乳剂的TPN支持对肝脏外科患者术后的肝功恢复有益,能促进蛋白质合成及肝细胞再生,并且在进行TPN支持时按1g·kg-1·d-1给予脂肪乳剂较为安全合理。 相似文献
94.
Emine Sözeri Dietrich Feist Hans Ruder Karl Schärer 《Pediatric nephrology (Berlin, Germany)》1997,11(3):307-311
Renal lesions have repeatedly been described in Wilson’s disease (WD). We investigated the excretion of total protein, albumin,
low (LMW) and high molecular weight (HMW) proteins, N-acetyl-β-D-glucosaminidase (NAG), and calcium, as well as creatinine clearance, in 24-h urine samples of 41 patients with WD aged 6 – 37
(mean 17) years who had been treated for a period of 0 – 15 (mean 4.5) years with D-penicillamine (900 mg/day). The amount of all protein excreted was significantly increased compared with controls, 39% of
patients presenting with total proteinuria more than two standard deviations from the mean of controls. The changes in protein
excretion depended on the duration of treatment. LMW proteinuria was elevated almost exclusively in the first 2 years after
the start of treatment, indicating early tubular damage. This is supported by an initially high excretion of β2-microglobulin, NAG, and calcium. Increased excretion of HMW proteins, including albumin, persisted over longer periods, which
suggests glomerular injury in some patients, possibly related to the use of D-penicillamine. Creatinine clearance remained roughly within normal limits. We propose that renal function should regularly
be checked in patients with WD.
Received October 26, 1995; received in revised form August 27, 1996; accepted September 20, 1996 相似文献
95.
96.
本文报告了葡萄糖酸锌糖浆的制法及用二甲橙指示剂法测定含量的方法。结果表明制法简便,含量测定方法准确。 相似文献
97.
Acute toxicity of two pyrethroids,permethrin, and cypermethrin in neonatal and adult rats 总被引:2,自引:0,他引:2
Franco Cantalamessa 《Archives of toxicology》1993,67(7):510-513
The present study aims specifically at obtaining a comparison of the acute toxicity of cypermethrin (CY), a type I pyrethroid, and permethrin (PERM), a type II pyrethroid, administered orally as a single dose to neonatal and adult rats, and at assessing the importance of pyrethroid biotransformation in CY and PERM toxicity through use of drug metabolism inhibitors. Our experiments show that CY is more toxic than PERM to adult and neonatal rats. The sensitivity of neonatal rats both to CY and to PERM toxicity is higher, the younger the animals. CY is much more toxic than PERM in the neonatal rat, compared with the adult. In rats aged 8, 16, and 21 days, pretreatment with piperonil butoxide (PB), a monooxygenase inhibitor, or with tri-o-tolyl phosphate (TOTP), an esterase inhibitor, does not produce significant variations in the lethal effects of CY and PERM. Instead, in the adult rats, a significant increase in CY (X2=5.97;p<0.05) and PERM (X2=4.37;p<0.05) mortality occurred in rats pretreated with esterase inhibitors, whereas no increase in CY and PERM toxicity was found in adult animals pretreated with monooxygenase inhibitor. It was concluded that the higher level of sensitivity of the neonate rat to pyrethroid toxicity is probably due to incomplete development of the enzymes which catalyze the metabolism of pyrethroids in the liver of young animals. It is suggested that ester hydrolysis is an important pyrethroids detoxification reaction in the adult rat. 相似文献
98.
99.
100.
Tarek Sadek Hakim Mazouz Hedi Bahloul Roxana Oprisiu Najeh El Esper Isabelle El Esper Francis Boitte Michel Brazier Philippe Moriniere Albert Fournier 《Nephrology, dialysis, transplantation》2003,18(3):582-588
BACKGROUND: Sevelamer hydrochloride was recently proposed as a phosphate binder to prevent hypercalcaemia in place of calcium alkaline salts in dialysis patients. So far, it has been evaluated only in patients receiving calcitriol, without comparison with CaCO(3) alone, although the latter was found to be as effective as the combination of calcitriol and Al(OH)(3) in suppressing parathyroid hormone (PTH) without inducing hypercalcaemia and to have a better lowering effect on serum phosphate. Moreover, this bile salt binder may decrease serum 25-OH vitamin D. Therefore, we compared for 5 months two strategies for controlling moderate hyperparathyroidism: CaCO(3) alone vs sevelamer in conjunction with measures to increase calcium balance. METHODS: Forty-two patients were randomized: 21 continued their treatment with 4.8 g/day CaCO(3) and 21 were switched to sevelamer (initial dose: 2.4 g/day, increased to 4.4 g/day). Each month, when serum-corrected calcium decreased below 2.30 mmol/l, dialysate calcium was increased or alphacalcidol was given at each dialysis session, according to serum PO(4) levels. The following parameters were monitored: serum Ca, PO(4), bicarbonate and protein, weekly; and serum PTH, 25-OH vitamin D and total, LDL and HDL cholesterol monthly. RESULTS: Except for higher serum phosphate at month 1, lower serum bicarbonate at month 2 and lower LDL cholesterol at month 5 in the sevelamer group, no difference was found between the two groups. Compared with baseline levels, PTH increased and 25-OH vitamin D decreased significantly in both groups, these two parameters being inversely correlated. CONCLUSIONS: Given comparable control of plasma calcium, phosphate and 25-OH vitamin D, PTH control is comparable in both strategies. Sevelamer does not induce greater vitamin D depletion than CaCO(3). The transient decrease of serum bicarbonate after discontinuation of CaCO(3) in the sevelamer group suggests a less optimal prevention of acidosis. The sevelamer-induced decrease in LDL cholesterol gives this drug a potential advantage in cardiovascular prevention. 相似文献