全文获取类型
收费全文 | 2971篇 |
免费 | 121篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 179篇 |
妇产科学 | 137篇 |
基础医学 | 200篇 |
口腔科学 | 91篇 |
临床医学 | 269篇 |
内科学 | 688篇 |
皮肤病学 | 63篇 |
神经病学 | 171篇 |
特种医学 | 138篇 |
外科学 | 597篇 |
综合类 | 61篇 |
预防医学 | 78篇 |
眼科学 | 86篇 |
药学 | 188篇 |
中国医学 | 3篇 |
肿瘤学 | 124篇 |
出版年
2024年 | 1篇 |
2023年 | 22篇 |
2022年 | 45篇 |
2021年 | 70篇 |
2020年 | 33篇 |
2019年 | 45篇 |
2018年 | 62篇 |
2017年 | 58篇 |
2016年 | 75篇 |
2015年 | 96篇 |
2014年 | 112篇 |
2013年 | 168篇 |
2012年 | 215篇 |
2011年 | 234篇 |
2010年 | 130篇 |
2009年 | 100篇 |
2008年 | 236篇 |
2007年 | 249篇 |
2006年 | 226篇 |
2005年 | 219篇 |
2004年 | 203篇 |
2003年 | 166篇 |
2002年 | 107篇 |
2001年 | 77篇 |
2000年 | 44篇 |
1999年 | 33篇 |
1998年 | 20篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 1篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1963年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有3115条查询结果,搜索用时 140 毫秒
21.
The Clinical Value of the Ratio of Free Prostate Specific Antigen to Total Prostate Specific Antigen
Objective: To examine the usefulness of the ratio of free prostate specific antigen (FPSA) to total prostate specific antigen (TPSA) in men with serum TPSA concentration of 4 to 10 ng/mL by using the cut off value of 0.15 for avoiding unnecessary biopsies.
Patients and methods: Two hundred thirty-six men aged between 52 and 91 with symptoms of prostatism were evaluated with digital rectal examination (DRE), FPSA and TPSA measurements. Patients with TPSA values under 4 ng/mL were biopsied if they had positive DRE and/or a FPSA/TPSA ratio lower than 0.15. All patients with TPSA values higher than 4 ng/mL were also biopsied. The predictive value and sensitivity of FPSA/TPSA ratio and TPSA alone were calculated.
Results: Eleven patients out of 170 with a TPSA value lower than 4 ng/mL were biopsied. Fifty-five patients had a value between 4.1 and 10 ng/mL. We performed transrectal ultrasound (TRUS) and prostate biopsy in these men except one patient. Biopsy proven prostate cancer was detected only in 12 patients. In this group of patients the predictive value of TPSA was 21%, but the predictive value of FPSA/TPSA ratio of 0.15 was 78% maintaining at least 90% sensitivity. Eleven of the patients had a prostate specific antigen (PSA) value higher than 10 ng/mL. In 6 of these patients the biopsy result was prostate cancer and 10 of these patients had a FPSA/TPSA ratio lower than 0.15.
Conclusion: In patients with TPSA values between 4–10 ng/mL the cut off value of FPSA/TPSA ratio of 0.15 can be used to eliminate unnecessary biopsies with minimal loss of cancer patients. 相似文献
22.
The aim of this study was to establish whether prostanoids play a role in the contraction induced by cyclosporine A (CyA) preparations in the guinea pig isolated gallbladder strips. It was also aimed to study the effects of the preparations and their solvents on the acetylcholine-evoked rhythmic contractions of the guinea pig isolated sphincter of Oddi (SO). Isometric contractions were recorded. CyA parenteral and oral preparations and their vehicles, Cremophor-EL and Labrafil caused concentration-dependent and sustained contractions (74.2 +/- 6.2, 58.4 +/- 6.3, 88.9 +/- 4.9 and 47.5 +/- 6.2% of maximum KCl contraction, respectively) of gallbladder strips, but not of SO. Quinacrine, indometacin and ridogrel inhibited the contraction induced by CyA preparations and their vehicles in gallbladder strips (for CyA parenteral preparation, 34.7 +/- 6.7, 1.4 +/- 0.9, 19.0 +/- 6.4% of maximum KCl contraction, respectively). The drug and its vehicles changed neither the initial contraction nor the amplitude and frequency of the phasic contractions induced by acetylcholine in SO preparations. The results indicate that the drug is able to contract the gallbladder strips and the vehicles contribute to the contracting effect of CyA. Prostanoids may be responsible for the CyA-induced contraction of the gallbladder. 相似文献
23.
Mustafa Cengiz Cem Onal Ferah Yildiz A Faruk Zorlu 《Radiotherapy and oncology》2004,73(1):109; author reply 109-109; author reply 110
24.
Kazancioğlu R Sever MS Yüksel-Onel D Eraksoy H Yildiz A Celik AV Kayacan SM Badur S 《Clinical transplantation》2000,14(1):61-65
BACKGROUND: Streptococcus pneumoniae, a common pathogen leading to pneumonia, is a cause of morbidity and mortality in immunosuppressed patients. Vaccination against this agent can be recommended for immunosuppressed patients, including those with chronic renal failure, nephrotic syndrome and renal transplant recipients; however, a diminished immune response and loss of protective antibodies have been observed. PATIENTS AND METHODS: In our prospective study, the efficacy and side effects of polyvalent pneumococcal vaccination were investigated in renal transplant recipients. A total of 21 patients (6 female, 15 male) with well-functioning renal allografts, who had transplant surgery at least 2 months before, were included in the study. The patients were stratified according to the immunosuppressive protocol and 8 received double, while 13 received triple, immunosuppressive agents. After obtaining basal serum samples, all cases were vaccinated with the 0.5 mL intramuscular administration of polyvalent polysaccharide pneumococcal vaccine (Pneumo 23 Pasteur Merieux, lot No: K 1131). RESULTS: Following a mean of 6 wk in all patients and also a mean of 12 wk in 12 patients, serum samples were again obtained to measure pneumococcal antibodies. Antibody titers following 6 and 12 wk of vaccination were significantly higher, as compared with basal values in all patients, except one. These titers did not show any statistically significant difference between double and triple therapies. There was no significant difference between the 12th and 6th wk postvaccination antibody titers. No systemic or local adverse effects were observed. CONCLUSION: Pneumococcal vaccination is safe and effective in patients with well-functioning renal allografts, at least in the short term. This vaccination policy may be useful for preventing invasive pneumococcal disease in immunosuppressed patients. 相似文献
25.
To test whether the improvements in digestive efficiency due to either wetting of the food or inclusion of enzymes are accompanied by the same changes in gut function, foods with a high content of wheat were fed to broiler chicks from 1-42 d old. Twenty-four birds were caged individually while a further sixty-four were in group pens in experiments of 2 x 2 factorial design with two levels of enzyme (0 or 1 g/kg, designed for wheat) and two levels of water addition (0 and 1300 g/kg). Food intake and live-weight gain were significantly increased by wet feeding (from 89.3 to 153.4 g/d and from 39.7 to 65.4 g/d respectively), the differences increasing with age, while the enzyme had no significant effect (120.5 and 122.2 g/d and 51.9 and 53.1g/week respectively). The viscosity of digesta was greatly reduced both by wetting (from 4.40 to 2.64 kPa. s) and enzyme (from 4.47 to 2.57 kPa. s) but there was a significant interaction with age in which the viscosity was low throughout in the wet only, enzyme only and wet + enzyme treatments but declined with age from a very high level in the dry, no enzyme treatment (11.5 kPa. s at 14 d). While wetting increased weight and length of digestive tract and thickness of some parts of the gut, enzyme had no significant effect, tending to reduce gut wall thickness. Crypt cell proliferation rate (CCPR) was significantly reduced by wet feeding (from 39.4 to 28.7 cells/crypt per 2 h) and by enzyme supplementation (from 38.9 to 29.2 cells/crypt per 2 h). Therefore, while both wetting and enzyme addition to the food reduced digesta viscosity and CCPR to a similar extent, the former had marked stimulatory effects on food intake and weight gain while the latter had little effect. The mode of action of wet feeding is therefore deduced to be not primarily through its effects on viscosity and CCPR. 相似文献
26.
Ismail Koramaz Mehmet Ozkan Murat Kesim Kibar Yasar Güven Mine Kadioglu Cunay Ulku Umit Cobanoglu Ersin Yaris Nuri Ihsan Kalyoncu Fahri Ozcan 《Pharmacological research》2005,51(6):567-573
Perioperative spasm of internal mammary artery is a common experience in coronary artery bypass grafting. Many techniques were described of harvesting the internal mammary artery to prevent vasospasm. We investigated the comparison of the contracting and relaxing responses of human internal mammary artery grafts harvested by two different methods. Patients were divided into two groups depending on the harvesting technique. In the first and second groups arteries were harvested by classical and carbon dioxide insufflation techniques, respectively. In both groups, endothelial function of arteries was assessed by precontracting the rings with phenylephrine (10(-5)M) and dilatating them by cumulative acetylcholine (10(-8) to 10(-5)M) concentrations. Cumulative concentration-response curves for phenylephrine (10(-8) to 10(-4)M), noradrenaline (10(-9) to 10(-4)M), and 5-hydroxytryptamine (10(-9) to 10(-4)M) were obtained in all groups. Endothelial integrity of arteries were histopathologically evaluated. In both groups, acetylcholine caused concentration-dependent relaxations in rings precontracted with phenylephrine (10(-5)M). In arteries harvested by carbon dioxide insufflation technique, acetylcholine caused significantly higher relaxations compared to the rings obtained by classical technique (p<0.05). In all rings of study groups, phenylephrine, noradrenaline and 5-hydroxytryptamine caused concentration-dependent contractions. There was not any significant difference in concentration-dependent responses of these contracting pharmacological agents between the groups. Histopathological evaluation revealed no major arterial damage in both groups. Carbon dioxide insufflation technique does seem not only to protect the integrity of the endothelium and the whole vessel, but also prevent the possible vasospasm of the internal mammary artery segments. 相似文献
27.
28.
29.
Ugur Selek Mustafa Cengiz Gokhan Ozyigit Ferah Yildiz Ibtisam Lale Atahan 《Radiotherapy and oncology》2005,76(1):107-8; author reply 108
30.
Burak Tekin MD Mehmet Salih Gurel MD Zeynep Topkarci MD Filiz Topaloglu Demir MD Sema Aytekin MD Filiz Cebeci Kahraman MD Ralfi Singer MD Vefa Asli Erdemir MD Tugba Kevser Uzuncakmak MD Sirin Yasar MD Necmettin Akdeniz MD Ilknur Kivanc Altunay MD Emek Kocaturk MD Zafer Turkoglu MD Bilgen Erdogan MD 《Pediatric dermatology》2018,35(5):651-659