全文获取类型
收费全文 | 870篇 |
免费 | 54篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 28篇 |
妇产科学 | 17篇 |
基础医学 | 111篇 |
口腔科学 | 17篇 |
临床医学 | 66篇 |
内科学 | 231篇 |
皮肤病学 | 9篇 |
神经病学 | 40篇 |
特种医学 | 73篇 |
外科学 | 126篇 |
综合类 | 10篇 |
预防医学 | 45篇 |
眼科学 | 64篇 |
药学 | 54篇 |
中国医学 | 2篇 |
肿瘤学 | 28篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 17篇 |
2021年 | 33篇 |
2020年 | 22篇 |
2019年 | 29篇 |
2018年 | 27篇 |
2017年 | 36篇 |
2016年 | 27篇 |
2015年 | 22篇 |
2014年 | 35篇 |
2013年 | 40篇 |
2012年 | 58篇 |
2011年 | 65篇 |
2010年 | 37篇 |
2009年 | 31篇 |
2008年 | 42篇 |
2007年 | 86篇 |
2006年 | 52篇 |
2005年 | 34篇 |
2004年 | 38篇 |
2003年 | 40篇 |
2002年 | 30篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 9篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 10篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 9篇 |
1980年 | 3篇 |
1978年 | 3篇 |
1976年 | 1篇 |
1968年 | 2篇 |
1964年 | 1篇 |
排序方式: 共有927条查询结果,搜索用时 15 毫秒
101.
102.
Kevin P. Barry M. Mesgarzadeh Joseph Triolo R. Moyer Jamshid Tehranzadeh Akbar Bonakdarpour 《Skeletal radiology》1996,25(4):365-370
The purpose of this study was to determine the different patterns of anterior cruciate ligament (ACL) tears on MRI and the
prevalence and accuracy of these patterns. Images were obtained on high-tesla and low-tesla units and the results compared
to determine whether field strength affects the interpretation using the grading system. In 172 patients who underwent knee
MRI (109 knees with high-tesla units and 63 knees with low-tesla units) and arthroscopy, there was a total of 91 arthroscopically
proven ACL tears. Five patterns of ACL tears were observed and designated as type 1 (diffuse increase in signal on T2-weighted
images and enlargement of the ligament, 48%); type 2 (horizontally oriented ACL, 21%); type 3 (nonvisualization of the ACL,
18%); type 4 (discontinuity of the ACL, 11%); and type 5 (vertically oriented ACL, 2%). The positive predictive value (PPV)
for type 2, 4, and 5 patterns was 100% for both field strengths; for type 3 PPV was just above 80% for both field strengths.
The PPV value for type 1 was 90% for the high-tesla unit and 79% for the low-tesla, unit, which was not statistically significant.
Combining the results of both field strengths, the overall sensitivity and specificity were 93% and 89%, respectively. Arthroscopic
results were also used to determine the association between meniscal and ACL tears. Only 13% of ACL tears were isolated, the
rest being associated with meniscal tears. Forty-five percent of medial meniscal and 50% of lateral meniscal tears were associated
with an ACL tear, and 94% of ACLs were torn when both menisci were torn. 相似文献
103.
We analyzed various biochemical variables of the bones in fetal rats whose dams were protein-energy malnourished. Dams were randomly divided into two groups and fed either a 6% protein diet as a malnourished group or a 20% protein diet as a control, from day 13 of gestation to day 22, when fetuses were removed. Hexosamine and hydroxyproline contents of the calvaria and hexosamine contents of long bones were greater in the malnourished group than in the controls. Sequential extractability of collagen differed among various bones in the malnourished group and controls. The ratio of alpha:beta obtained from SDS-polyacrylamide gel of neutral salt-soluble collagen tended to increase in the long bones and mandible, and decrease in the calvaria and ribs in the malnourished group. Also, the ratio of alpha 1:alpha 2 tended to be lower in the malnourished group than in the control group in all bones. Protein-energy malnutrition during pregnancy has shown to affect biochemical composition of various fetal bones. 相似文献
104.
At birth, dams with 8 randomly assigned pups were divided into three groups. Dams of group 1 were fed a control diet. Dams of groups 2 and 3 were fed the control diet supplemented with caffeine (1 mg and 2 mg/100 g body weight, respectively). Pups were killed at day 15 and their brains removed. After weighing, brains were analyzed for DNA, protein, cholesterol, zinc and alkaline phosphatase activity. Brain and plasma caffeine levels were also determined on groups 2 and 3. The dams were milked to measure caffeine levels. The brains from the dams were analyzed for the same parameters as the pups. Caffeine levels in group 3 were consistently higher than in group 2. In the pups, body and brain weights were heavier in group 3 than in the controls. Protein and cholesterol concentrations in group 2 were less than either controls or group 3. Alkaline phosphatase activity in group 2 was higher than either controls or group 3. In the dams, DNA concentration in groups 2 and 3 was less than the controls. Protein and cholesterol concentration in group 2 was less than group 3. It was concluded that low levels of caffeine in the maternal diet during lactation could affect various parameters in the newborn brain. These effects were different from those when the dietary caffeine level was doubled. In contrast, the effects of caffeine on brains of the dams were relatively minor. 相似文献
105.
Jamshid Ahmadi Jong S. Han James S. Teal Fong Y. Tsai Chi-Shing Zee Hervey D. Segall 《Surgical neurology》1982,17(3):209-212
The superior portion of the coronal suture is often easily identified by appropriately setting the window width and level of the CT scanner's display system. It provides a valuable and practical reference point for the localization of intracranial lesions, particularly those above the level of the lateral ventricles, where fewer anatomical landmarks are available when using computed tomography. 相似文献
106.
An ectopic ureter ending in a seminal vesicle and associated with renal agenesis is a rare occurrence. There are no reports of this anomaly occurring with gross, total, painless hematuria as presenting symptom. Sonography and catheterization of the ejaculatory duct were the most helpful diagnostic studies used to demonstrate the abnormality. Surprisingly, on pathologic examination, the cystic area was not seminal vesicle but a dilated hemorrhagic ureter. 相似文献
107.
Ramezani AR Ahmadieh H Ghaseminejad AK Yazdani S Golestan B 《The British journal of ophthalmology》2005,89(8):1041-1044
AIMS: To evaluate the effect of tranexamic acid on early postvitrectomy haemorrhage in diabetic patients. METHODS: In a clinical trial, 62 diabetic patients scheduled for vitrectomy were randomly assigned to two groups. The treatment group (32 eyes) received two doses of tranexamic acid (10 mg/kg) shortly before and after the operation intravenously, continued orally for 4 days (20 mg/kg/8 hours). The control group (30 eyes) received no medication. Both media clarity and visual acuity were compared during 4 weeks. RESULTS: Four weeks after surgery visual acuity was low (< or =1 metre counting fingers) in 21.4%, moderate (>1 metre counting fingers but<20/200) in 14.3%, and good (> or =20/200) in 64.3% of the treated group. Corresponding figures in the control group were 26.1%, 26.1%, and 47.8%, respectively. These differences were of no statistical significance. The ratio of mild to severe vitreous haemorrhage during the first 4 days and after 4 weeks was 79% to 21% and 82% to 18% in the treatment group and 76.7% to 23.3% and 78.3% to 21.7% in the control group respectively, which showed no statistically significant difference. CONCLUSION: Tranexamic acid, with the method of administration in this study, had no effect on reducing early postvitrectomy haemorrhage in diabetic patients. 相似文献
108.
Javadi MA Jafarinasab MR Araghi AA Mohammadpour M Yazdani S 《Journal of cataract and refractive surgery》2005,31(5):997-1001
PURPOSE: To evaluate the visual outcomes and complications of phacoemulsification (PE) and posterior chamber intraocular lens implantation, (PC IOL) in patients with Fuchs heterochromic iridocyclitis (FHIC). SETTING: Private clinic and an academic hospital. METHODS: In this noncomparative interventional case series, existing data for 41 eyes of 40 consecutive patients clinically diagnosed with FHIC and cataract were studied retrospectively. Scleral tunnel PE and in-the-bag IOL implantation were performed in all cases. Preoperative and postoperative visual acuities and intraoperative and postoperative complications were evaluated. RESULTS: Twenty-four male and 16 female patients aged 12 years to 70 (SD) (mean 35 +/- 12 years) were operated on and followed for 17.8 +/- 8.7 months. Preoperatively, best corrected visual acuity (BCVA) was less than 20/40 in all patients, which improved to 20/40 or better after surgery. Twenty-two eyes (53.6%) achieved BCVA of 20/20. The major cause of postoperative visual acuity less than 20/20 was vitreous haze. There were no major intraoperative complications. Postoperatively, mild anterior chamber fibrin reaction occurred in 4 patients (9.7%), IOL deposits occurred in 11 eyes (26.8%), and decentration was observed in 1 eye. During follow-up, 6 eyes (14.6%) developed posterior capsule opacification requiring a neodymium:YAG (Nd:YAG) laser capsulotomy. There was 1 case of clinical cystoid macular edema that resolved with medication. There were no cases of posterior synechias, postoperative glaucoma, or retinal detachment. CONCLUSION: Phacoemulsification with PC IOL implantation is a safe procedure with good visual outcomes in patients with FHIC and cataract. 相似文献
109.
110.
Arash Bidadkosh Amin Derakhshanfar Amir Mahmoud Rastegar Saleh Yazdani 《Comparative clinical pathology》2012,21(6):1739-1744
Nephrotoxicity results from an abrupt decline in glomerular functions of the kidney and is regarded as a major cause of concern for limiting therapeutic uses of gentamicin in hospital settings. Recent evidences suggest that both endothelial nitric oxide synthesis (eNOS) and inducible NOS (iNOS)-derived nitric oxide (NO) vasodilators reduce renal toxicity, restoring normal glomerular functions and hemodynamic stability, but this has not been adequately investigated in gentamicin nephrotoxicity. To determine the isoform of NOS that plays a predominant role in the control of glomerular vasodilation under the oxidative stress of nephrotoxicity, we conducted a controlled, randomized study in five equal groups of ten Sprague–Dawley rats. All animals were given a corresponding dose of either normal saline, only l-arginine, only gentamicin, or a combination thereof with and without N-3-aminomethyl benzylacetamidine (a selective iNOS inhibitor, 1400W) for 9?days. After 6?days, gentamicin-treated rats developed nephrotoxic alterations evident by a significant fall in renal blood flow and glomerular filtration rate, increased urinary excretion of gamma glutamyl transpeptidase and serum concentration of inflammatory interleukins (IL-6 and IL-8) as well as a decrease in the tissue antioxidant activity of superoxide dismutase. Changes in these biochemical variables were completely inhibited by supplemented l-arginine up to 9?days. However, a combination of 1400W partially removed protective effects of l-arginine on the glomerular hemodynamics of the kidney. Our results suggest that at irradiation of eNOS developed by increased oxidative process, administration of l-arginine increases iNOS-derived NO production and glomeruli infiltration on its direct antioxidant effects counteracting the undesirable effects of peroxynitrite formation on the kidney. 相似文献