全文获取类型
收费全文 | 20218篇 |
免费 | 927篇 |
国内免费 | 251篇 |
专业分类
耳鼻咽喉 | 104篇 |
儿科学 | 458篇 |
妇产科学 | 766篇 |
基础医学 | 1138篇 |
口腔科学 | 131篇 |
临床医学 | 6645篇 |
内科学 | 3015篇 |
皮肤病学 | 169篇 |
神经病学 | 1877篇 |
特种医学 | 1141篇 |
外科学 | 1233篇 |
综合类 | 2773篇 |
现状与发展 | 1篇 |
预防医学 | 509篇 |
眼科学 | 211篇 |
药学 | 823篇 |
6篇 | |
中国医学 | 210篇 |
肿瘤学 | 186篇 |
出版年
2024年 | 24篇 |
2023年 | 119篇 |
2022年 | 274篇 |
2021年 | 401篇 |
2020年 | 462篇 |
2019年 | 400篇 |
2018年 | 461篇 |
2017年 | 397篇 |
2016年 | 415篇 |
2015年 | 417篇 |
2014年 | 1015篇 |
2013年 | 1097篇 |
2012年 | 983篇 |
2011年 | 1125篇 |
2010年 | 998篇 |
2009年 | 1037篇 |
2008年 | 1083篇 |
2007年 | 1154篇 |
2006年 | 1171篇 |
2005年 | 1086篇 |
2004年 | 963篇 |
2003年 | 752篇 |
2002年 | 676篇 |
2001年 | 706篇 |
2000年 | 567篇 |
1999年 | 512篇 |
1998年 | 414篇 |
1997年 | 419篇 |
1996年 | 374篇 |
1995年 | 339篇 |
1994年 | 273篇 |
1993年 | 232篇 |
1992年 | 201篇 |
1991年 | 177篇 |
1990年 | 134篇 |
1989年 | 77篇 |
1988年 | 84篇 |
1987年 | 62篇 |
1986年 | 58篇 |
1985年 | 76篇 |
1984年 | 43篇 |
1983年 | 32篇 |
1982年 | 41篇 |
1981年 | 20篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 10篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1974年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
目的 :观察氯沙坦对行维持性血透治疗的慢性肾功能衰竭 (CRF)患者心血管保护作用。方法 :6 0例维持性血透患者 (血肌酐≥ 70 0 μmol·L- 1 ) ,治疗组 (给予氯沙坦 5 0~ 10 0mg·d- 1 )及对照组 (给予非血管紧张素受体拮抗剂和非ACEI类降压药 )各 30例 ,记录用药前后各组患者血压 ,运用多普勒组织成像 (DTI)技术观察用药前后两组患者二尖瓣环峰值收缩速度 (VS)、收缩时间速度积分 (TVIS)、舒张早期速度 (VE)、舒张晚期速度 (VA)、VE VA 比值。结果 :治疗组及对照组患者治疗后血压均明显下降 ,二尖瓣环VS、TVIS、VE、VE VA ,则均明显上升 ;治疗组与对照组血压分别在治疗前、后相比并无明显差异 ;治疗前两组间二尖瓣环VS、TVIS、VE、VE VA 并无显著性差异 ,但在治疗12个月后 ,治疗组二尖瓣环VS、TVIS、VE、VE VA 则明显高于对照组。结论 :氯沙坦对行持续性血透的CRF患者具有良好的心脏保护作用 ,可有效改善其心功能 ,且不依赖于其降压作用 相似文献
73.
74.
75.
G. RAYMAN S. A. WILLIAMS J. GAMBLE J. E. TOOKE 《European journal of clinical investigation》1994,24(12):830-836
Abstract. The effect of lowering the foot on the factors governing fluid filtration in the foot were studied in 12 male insulin-dependent diabetic subjects and 10 controls. Toe skin blood flow, measured by laser Doppler flowmetry, was significantly higher during dependency in the diabetic group. In the control subjects, the colloid osmotic pressure of venous blood sampled from the foot rose to 47·7 mmHg (range 45·1–53·8) after 50 min of foot dependency. In the diabetic group, colloid osmotic pressure failed to rise to the same extent (median 36·7 mmHg; range 28·6–43·0; P < 0·001). Capillary pressure, measured directly by the Landis microinjection technique, was significantly higher in the diabetic group (85·3±1·7 ( n = 6) vs. 92·2±4·6 cm H2 O ( n = 6); P < 0·007), as was foot swelling rate determined by mercury strain gauge plethysmography (0·069±0·022 vs. 0·099±0·025 ml min-1 100ml-1 ; P < 0·02). These results suggest an impairment of the oedema-preventing mechanisms in diabetic subjects which may contribute to the risks of ulceration in the diabetic foot. 相似文献
76.
Summary: We studied the effect of antiepileptic drugs (AEDs) on internal carotid artery (ICA) blood flow velocity, as an index of total cerebral blood flow (CBF). The subjects were 45 newly diagnosed children with febrile convulsion or epilepsy who were seizure-free for a period long enough not to affect the results. They had no neurologic deficit, received fixed monotherapy, and were examined by a noninvasive Doppler ultrasound method, in comparisonwith 13 age-matched normal volunteers with no AED. In 30 patients, the measurements were performed before and after AED administration [10 with phenobarbital (PB), 10 with carbamazepine (CBZ), and 10 with valproate (VPA)], and performed before and after AED discontinuation in the remaining 15 patients (all with PB). Normal volunteers underwent the two consecutive examinations with a mean interval equal to that of the entire patient group, and there was no difference in velocity values between the measurements. In patients receiving CBZ or VPA, a significant reduction was noted in blood flow velocity after drug administration. Although velocity values in the patients receiving PB did not change after drug administration, they were significantly increased after complete discontinuation. In the present study, a slight but significant reduction in CBF caused by AED administration at therapeutic doses in children was suggested. 相似文献
77.
脐动脉血流速波、产前胎心监护及脐动脉血气分析与新生儿结局的对比研究 总被引:1,自引:0,他引:1
测定115例足月妊娠者(正常妊娠62例,高危妊娠53例)脐动脉血流速波(UmAS/D),同时作产前胎心电子监护(NST),其中37例于分娩时抽取脐动脉血作血气分析。对上述三种方法预测新生儿结局的效果进行比较。结果表明:UmAS/D、脐动脉血的pH值较NST对新生儿结局不良有较好的预测性,异常UrnAS/D与新生儿酸中毒有密切关系。 相似文献
78.
HIROMI KUMON HIDEO OZAWA HIROYUKI NOSE HIDEKUNI OHTA KAZU NISHIGAKI 《International journal of urology》2004,11(8):628-633
BACKGROUND: We have developed velocity-flow urodynamics using Doppler sonography based on the hypothesis that microbubbles formed in the urethra are responsible for Doppler signals. In order to confirm this hypothesis derived from Bernoulli's principle, we investigated the simultaneous detection of cavitation noise and Doppler signals in an experimental system. METHODS: An experimental circuit was built in which a stenosis was created using a glass or silicon tube with tap water used as the sample fluid. Doppler signals, pressure before and after the stenosis, flow rate, flow velocity and cavitation noise were measured. Direct detection of cavitation with a high-speed charged-coupled device (CCD) camera was conducted in the glass tube. The relationship between cross-sectional area and flow velocity in terms of the detection of Doppler signals was analyzed in the silicon tube study. RESULTS: In the glass tube study, a high-speed CCD camera clearly detected masses of microbubbles associated with cavitation. The range of flow rates creating cavitation completely corresponded with those producing Doppler signals detected by ultrasonography. A similar correlation was observed in the silicon tube study, which showed that a low flow velocity of 41.5 cm/sec through a stenosis with a cross-sectional area of 20 mm(2) created Doppler signals at a flow rate of 8.3 mL/sec. CONCLUSION: The results of the present study confirmed that microbubbles created in flowing urine are responsible for Doppler signals. Measurement of velocity-flow urodynamics has great potential to become a non-invasive and reliable alternative to conventional pressure- flow urodynamic studies. 相似文献
79.
M. Bertolotto G. Serafini L. Dogliotti N. Gandolfo N. G. Gandolfo M. Belgrano F. Prefumo 《Abdominal imaging》2004,30(1):108-112
Cancer of the penis is a rare neoplasm in developed countries but worldwide represents a significant health problem. In this
study, the ultrasonographic features of primary and secondary malignant lesions of the penis are described. Squamous cell
carcinoma usually presents as a hypoechoic lesion with heterogeneous appearance. Invasions of the corpora cavernosa and the
corpus spongiosum are appreciable. B-cell lymphoma presents as a well-vascularized mass, a plaque, or ulcers in the penile
skin. Penile metastases result from hematogenous or lymphatic spreading of distant tumors or, more frequently, as penile infiltration
by tumors from adjacent organs. Diffuse corporeal or nodular involvement can result.
1Award-winning poster at the 10th European Symposium on Urogenital Radiology; Uppsala, Sweden, September 4•7, 2003. 相似文献
80.