全文获取类型
收费全文 | 7821篇 |
免费 | 524篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 80篇 |
儿科学 | 199篇 |
妇产科学 | 247篇 |
基础医学 | 908篇 |
口腔科学 | 293篇 |
临床医学 | 681篇 |
内科学 | 1677篇 |
皮肤病学 | 216篇 |
神经病学 | 378篇 |
特种医学 | 258篇 |
外国民族医学 | 4篇 |
外科学 | 1272篇 |
综合类 | 163篇 |
现状与发展 | 2篇 |
一般理论 | 3篇 |
预防医学 | 440篇 |
眼科学 | 198篇 |
药学 | 858篇 |
中国医学 | 71篇 |
肿瘤学 | 435篇 |
出版年
2023年 | 111篇 |
2022年 | 290篇 |
2021年 | 456篇 |
2020年 | 290篇 |
2019年 | 366篇 |
2018年 | 469篇 |
2017年 | 299篇 |
2016年 | 305篇 |
2015年 | 295篇 |
2014年 | 329篇 |
2013年 | 452篇 |
2012年 | 601篇 |
2011年 | 535篇 |
2010年 | 331篇 |
2009年 | 266篇 |
2008年 | 372篇 |
2007年 | 350篇 |
2006年 | 321篇 |
2005年 | 350篇 |
2004年 | 271篇 |
2003年 | 244篇 |
2002年 | 218篇 |
2001年 | 70篇 |
2000年 | 53篇 |
1999年 | 57篇 |
1998年 | 40篇 |
1997年 | 34篇 |
1996年 | 39篇 |
1995年 | 32篇 |
1994年 | 16篇 |
1993年 | 24篇 |
1992年 | 32篇 |
1991年 | 35篇 |
1990年 | 32篇 |
1989年 | 29篇 |
1988年 | 32篇 |
1987年 | 32篇 |
1986年 | 29篇 |
1985年 | 34篇 |
1984年 | 20篇 |
1983年 | 24篇 |
1982年 | 13篇 |
1981年 | 20篇 |
1980年 | 22篇 |
1979年 | 23篇 |
1977年 | 12篇 |
1976年 | 15篇 |
1975年 | 18篇 |
1974年 | 10篇 |
1972年 | 10篇 |
排序方式: 共有8383条查询结果,搜索用时 0 毫秒
71.
72.
Al-Bahry SN Al-Mashani BM Al-Ansari AS Elshafie AE Mahmoud IY 《Asian Pacific journal of tropical medicine》2013,6(9):718-722
ObjectiveTo screen for Escherichia coli (E. coli) resistant to tetracycline, followed by identification of tet efflux genes by polymerase chain reaction (PCR). In addition, detection of tetracycline residues in chicken livers and kidneys were conducted using high performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS).MethodsStrains of E. coli were isolated from samples of chicken colon and screened for tetracycline resistance. Tetracycline genes conferring resistance (Tcr) were detected by polymerase chain reaction (PCR). Most of the isolates were resistant to tetracycline (97.9%).ResultsPCR analysis indicated that Tcr E. coli R-plasmids contained tet(A), tet(B) and a combination of both efflux genes. None of the isolates contained other efflux tet genes tet (C, D, E and Y). High performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS), a sensitive technique, was used to detect residues of chlortetracycline (CTC), oxytetracycline (OTC), doxycycline (DC) in chicken livers and kidneys. The samples containing tetracycline residues were at 0.13-0.65 pg/μL levels.ConclusionsTetracycline and other antibiotics are commonly used in the poultry and meat production industry for prevention of microbial infections. Multiple antibiotic resistant bacteria in Oman have increased to alarming levels, threatening public health, domestic and may have adverse effect on environment. 相似文献
73.
74.
75.
Nahed Mounir Sherif Mona Mahmoud Arafa Soha Eldessouki Ibrahim Salwa Galal Moussa 《The Egyptian Rheumatologist》2013,35(3):121-126
Aim of the workThe aim of the present study was to measure the level of the chemokine CXC ligand 13 protein (CXCL13) in the plasma and unstimulated saliva of rheumatoid arthritis (RA) patients in order to find out its role in the disease activity and its relation to secondary Sjögren’s syndrome (sSS).Patients and methodsThe study was conducted on thirty rheumatoid arthritis patients attending the Outpatient Clinic of Rheumatology and Rehabilitation department of Ain shams University Hospitals. The patients’ group had been classified into group (1) which included fifteen RA patients associated with sSS diagnosed according to the American–European Consensus Group Classification Criteria and group (2) which included fifteen RA patients not associated with sSS. Ten healthy subjects were included as a control group. Patients were subjected to full history taking, clinical examination, and laboratory detection of CXCL13 level in the plasma and saliva of patients as well as the control groups using ELISA technique. Assessment of disease activity in RA patients was done using the disease activity score (DAS28).ResultsPlasma levels of CXCL13 were significantly higher in RA patients than control group (p < 0.001). Plasma levels of CXCL13 were significantly correlated with the RA disease activity (r = 0.677, p < 0.001) and disease duration (r = 0.406, p < 0.05), while the salivary levels were higher in those with sSS and correlated with sSS disease duration (r = 0.536, p < 0.05). A highly significant correlation was found between salivary CXCL13 and severity of sSS (r = 0.816, p < 0.001). Salivary levels of CXCL13 above 110 pg/ml may diagnose sSS with sensitivity 80% and specificity 84%.ConclusionThe results of this preliminary study point out the importance of CXCL13 as a marker for RA disease activity, its role in diagnosing sSS, and estimation of sSS severity. 相似文献
76.
Background and aim of the workCardiovascular mortality and morbidity are significantly higher among uremic patients. Although the carotid intimal–medial thickness (C-IMT) as a predictor of endothelial dysfunction (ED) has a prognostic value that has been well demonstrated as an independent predictor of future cardiovascular events, its value in uremic patients need to be re-assisted in our locality. The aim of the work is to investigate a correlation between the brachial artery reactivity test (BART) and the carotid intimal–medial thickening (C-IMT) and their value as independent predictors of endothelial dysfunction in uremic patients.Subjects and methodsThe study involved 70 uremic patients, 40 men and 30 women, 36–56 years old, 40 of them on regular hemodialysis (HD) and 30 on conservative therapy, in addition to 30 healthy persons as a control group. They were selected from the General Medicine and Nephrology Departments, Al-Azhar Assiut University and Assiut University Hospitals over a period of 2 years. All of them were subjected to detailed history, thorough clinical examination, laboratory investigations including complete blood picture, renal function tests (urine analysis, blood urea, and serum creatinine), lipid profile, serum calcium and serum phosphorus, parathyroid hormone (PTH), fasting blood glucose, electrocardiography (ECG), high resolution B-mode ultra-sonography for C-IMT evaluation and brachial artery reactivity test (BART), and abdominal ultra-sonography.ResultsThe results of the present study showed: (1) uremic patients are at an increased risk for carotid atherosclerotic lesions, with significant increase in C-IMT than controls with more significant increase in HD patients. (2) Uremic patients are characterized by impaired endothelium dependent dilatation of the brachial artery (highly significant reduction in flow-mediated dilatation (FMD%)), an abnormality related to the renal failure severity and to the hemodialysis doses. The endothelial dysfunction in the brachial artery was more pronounced in HD patients than in patients on conservative therapy. (3) Significant positive correlation between increased C-IMT and reduction of the brachial FMD%. (4) Significant relation between C-IMT and plaque prevalence and HD duration, while no relations recorded between brachial FMD with HD duration.Conclusion(1) The study confirmed that carotid IMT and brachial artery FMD can be used in interventional studies in which cardiovascular risk is modified and increased in the uremic patients. (2) There was negative correlation between brachial FMD and C-IMT in the uremic patients. 相似文献
77.
78.
Arastoo Saeedi Reza Fardid Mohammad Javad Khoshnoud Elaheh Kazemi Mahmoud Omidi 《Xenobiotica; the fate of foreign compounds in biological systems》2017,47(6):547-552
1.?The prevalence of diabetes and the other metabolic disorders has noticeably increased worldwide. A causal link between increasing risk of type 2 diabetes and exposure to environmental pollutants has been reported.2.?We hypothesized that exposure to methyl tert-butyl ether (MTBE), an oxygenate additive to gasoline would hinder zinc and glucose homeostasis in rats.3.?Male Sprague–Dawley rats received MTBE in drinking water for 90 days. At the end of the treatment, pancreas and blood samples were collected for biochemical and molecular examinations. Expression of four candidate genes, including Insulin1, Insulin2, MT1A, SLC30A8 by Real-Time Quantitative PCR (Q-PCR) as well as biochemical parameters, including fasting blood glucose (FBS), triglycerides (TG), cholesterol (CHO), low-density lipoprotein (LDL), high-density lipoprotein (HDL), copper (Cu2+) and calcium (Ca2+) levels as well as High-sensitive C-reactive protein were assessed as endpoints.4.?This study suggested that MTBE exposure can be associated with disruption in zinc homeostasis and glucose tolerance. 相似文献
79.
Sawsan A. Oran 《Pharmaceutical biology》2013,51(4):296-299
Fifteen different plants representing different species, genera and families were used to test the effect of their aqueous extracts on tumor inhibition with a rapid, inexpensive, safe, animal sparing technique, and statistically reliable prescreen for in vivo murine leukemia antitumor activity, which is known as potato disc technique. The inoculum used contains the extract with the bacterium (Agrobacterium tumefaciens) that was known to cause crown gall tumor to different plant species especially dicotyledons and some gymnosperms. After 12 to 21 days of incubation the tumors appeared and were counted, and the maximum inhibition was then calculated. Thirteen species out of fifteen showed a good antitumor effect, and three of them showed a maximum inhibition of 80%. More experiments are necessary to determine the exact mechanism of action. 相似文献
80.
Activation of central GABAB receptors offsets the cyclosporine counteraction of endotoxic cardiovascular outcomes in conscious rats 下载免费PDF全文
Marwa Y. Sallam Sahar M. El‐Gowilly Abdel‐Galil A. Abdel‐Galil Mahmoud M. El‐Mas 《Fundamental & clinical pharmacology》2018,32(5):485-498
We have previously shown that cyclosporine (CSA) counteracts cardiovascular manifestations induced by endotoxemia (lipopolysaccharide, LPS) such as hypotension and cardiac autonomic dysfunction in conscious rats. In this study, we investigated whether the facilitation of central γ‐amino butyric acid (GABA) neurotransmission blunts these favorable influences of CSA. The LPS‐CSA interaction was determined in the absence and presence of drugs that activate GABAA or GABAB receptors or elevate synaptic GABA levels in the central nervous system. The consequent i.v. administration of CSA (10 mg/kg) blunted the LPS‐evoked hypotension, tachycardia, and reductions in time‐ and frequency‐domain indices of heart rate variability (measures of cardiac autonomic control) evoked by LPS (10 mg/kg i.v.). The ability of CSA to reverse the LPS effects disappeared in rats treated intracisternally (i.c.) with baclofen (selective GABAB agonist, 2 μg/rat) but not muscimol (selective GABAA agonist, 1 μg/rat), indicating a preferential compromising action for central GABAB receptors on the advantageous effects of CSA. Moreover, the improvement by CSA of LPS‐evoked cardiovascular derangements was also eliminated after concurrent i.c. administration of vigabatrin (GABA transaminase inhibitor, 200 μg/rat) or tiagabine (GABA reuptake inhibitor, 100 μg/rat). These results demonstrate that the activation of central GABAB receptors either directly via baclofen or indirectly following interventions that boost GABA levels in central synapses counterbalances the rectifying action of CSA on endotoxemia. 相似文献