全文获取类型
收费全文 | 517047篇 |
免费 | 30942篇 |
国内免费 | 587篇 |
专业分类
耳鼻咽喉 | 6906篇 |
儿科学 | 16855篇 |
妇产科学 | 13524篇 |
基础医学 | 85074篇 |
口腔科学 | 14486篇 |
临床医学 | 44426篇 |
内科学 | 93782篇 |
皮肤病学 | 12167篇 |
神经病学 | 36258篇 |
特种医学 | 18461篇 |
外国民族医学 | 63篇 |
外科学 | 77103篇 |
综合类 | 8476篇 |
一般理论 | 118篇 |
预防医学 | 38978篇 |
眼科学 | 12150篇 |
药学 | 40562篇 |
4篇 | |
中国医学 | 1007篇 |
肿瘤学 | 28176篇 |
出版年
2018年 | 4943篇 |
2015年 | 4513篇 |
2014年 | 6068篇 |
2013年 | 9557篇 |
2012年 | 12872篇 |
2011年 | 14274篇 |
2010年 | 8303篇 |
2009年 | 7773篇 |
2008年 | 13703篇 |
2007年 | 14700篇 |
2006年 | 14938篇 |
2005年 | 14357篇 |
2004年 | 14049篇 |
2003年 | 13389篇 |
2002年 | 13273篇 |
2001年 | 24068篇 |
2000年 | 25079篇 |
1999年 | 20555篇 |
1998年 | 5428篇 |
1997年 | 4706篇 |
1996年 | 5041篇 |
1995年 | 4625篇 |
1994年 | 4318篇 |
1993年 | 4135篇 |
1992年 | 15725篇 |
1991年 | 16309篇 |
1990年 | 16422篇 |
1989年 | 15796篇 |
1988年 | 14575篇 |
1987年 | 14419篇 |
1986年 | 13597篇 |
1985年 | 12975篇 |
1984年 | 9627篇 |
1983年 | 8247篇 |
1982年 | 4559篇 |
1981年 | 4229篇 |
1979年 | 9418篇 |
1978年 | 6855篇 |
1977年 | 5772篇 |
1976年 | 5602篇 |
1975年 | 6396篇 |
1974年 | 7634篇 |
1973年 | 7130篇 |
1972年 | 6960篇 |
1971年 | 6685篇 |
1970年 | 6172篇 |
1969年 | 5888篇 |
1968年 | 5559篇 |
1967年 | 5012篇 |
1966年 | 4451篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Effect of phenytoin and nifedipine on collagen gene expression in human gingival fibroblasts 总被引:3,自引:0,他引:3
Tuula Salo Kyösti S. Oikarinen Aarne I. Oikarinen 《Journal of oral pathology & medicine》1990,19(9):404-407
Phenytoin (PHT), a widely used anticonvulsant, and nifedipine (NF), an anti-anginal drug, cause clinically similar gingival overgrowths in some patients. The aim of this work was to investigate their effects on collagen and protein synthesis and cellular proliferation in normal human gingival fibroblasts in vitro. Gingival fibroblasts were cultured from biopsies taken from three healthy individuals during operations on maxillary canines and incubated with various concentrations of NF (100 and 200 ng/ml) and PHT (5 and 10 micrograms/ml) for up to 7 days. The results showed that NF and PHT have a specific effect in reducing total protein and collagen synthesis but do not influence cell proliferation in healthy gingival fibroblasts in vitro. In addition the level of mRNA for type I collagen was decreased after incubation of the cells with the drugs for 1 or 2 days. The decrease in the level of type I collagen mRNA seemed to be specific since the level of type IV collagenase mRNA used as a reference RNA did not decrease. 相似文献
102.
J M van Ingen K de Man I Bakri 《The British journal of oral & maxillofacial surgery》1990,28(3):164-167
Synovial chondromatosis of the temporomandibular joint (TMJ) is a very rare condition. It is characterised by the presence of loose bodies in the joint space. Clinical signs, histopathological findings and radiography play an important role in the diagnostic process. Conventional X-rays have shown to be of limited value, for they fail to depict the intra-articular loose bodies in a significant amount of cases. Axial as well as coronal computer tomography (CT) is extremely useful in detecting loose bodies in the temporomandibular joint (TMJ). In this report we present and discuss a further case, and the use of CT in the diagnosis of TMJ-synovial chondromatosis is illustrated. 相似文献
103.
Longevity of posterior restorations 总被引:3,自引:0,他引:3
The efficacy of restorative dentistry is dependent on a number of factors, including material quality, operator proficiency and the oral hygiene of the patient. The sum effect of all factors can be measured by recording the longevity of the restorations. Many studies focus on the age of restorations at the time of failure, others include the longevity of restorations which remain in situ. The surveys may be either longitudinal, prospective or retrospective, or cross-sectional retrospective studies of dental records. They are all hampered by the lack of uniform criteria defining when to place and replace restorations and by variations in decision-making between clinicians. The present review paper shows that the longevity of amalgam restorations has been studied most frequently. About 50 per cent of all amalgam restorations exceed 8-10 years in age, cast gold restorations may last longer and multisurfaced composite restorations have a shorter life-span. Glass ionomer cements lack the physical properties needed for large posterior restorations. The results of detailed longevity studies should be the basis for selection of materials and techniques in operative/conservative treatment. The cost of dental treatment should be related to the expected lifetime of the tooth rather than to the immediate cost of a simple restoration. 相似文献
104.
K Shibasaki K Soga M Toshima K Aikawa T Itoh Y Takahashi M Tsuchimochi I Mataga K Tsuchikawa J Kato 《Shigaku. Odontology; journal of Nippon Dental College》1989,77(3):1031-1041
In order to study the clinical significance of ASP and IAP, we have measured serum concentration of ASP and IAP in 259 patients with inflammatory diseases, non-inflammatory diseases, autoimmune diseases and liver diseases. Significantly higher correlation (coefficient of correlation = 0.922) was found between ASP and IAP. There were good correlation between ASP, IAP levels and erythrocyte sedimentation rate (ESR), C-reactive protein (CRP). Coefficient of correlation were 0.705 and 0.673 between ESR and ASP, IAP; 0.621 and 0.623 between CRP and ASP,IAP, respectively. There were food correlations between ASP levels and thrombo test (TT) and hepaplastin test (HPT). The positive rate and mean concentration of ASP, IAP in patients with inflammatory diseases were significantly higher than noninflammatory diseases. It is suggested that serum ASP, IAP could be one of the useful indicator for evaluating the clinical course of patients with inflammatory diseases. Serum concentration of ASP, IAP in patients with chronic liver diseases were lower than normal subjects, especially serum levels in patients with decompensated liver cirrhosis and chronic hepatitis (active) were significantly lower than normal subjects. In patients with hepatoma with cirrhosis, serum levels of ASP, IAP were significantly lower than the hepatoma patients without cirrhosis. The determination of ASP, IAP in liver diseases seems to be useful for evaluating the severity of diseases, the effects of therapy and the forecast of prognosis. 相似文献
105.
Clinical evaluation of serum immunosuppressive acidic protein (IAP) and acid soluble glycoproteins (ASP) in patients with malignant tumors 总被引:1,自引:0,他引:1
K Shibasaki K Soga M Toshima K Aikawa T Tsuruya T Itoh Y Takahashi M Tsuchimochi I Mataga K Tsuchikawa 《Shigaku. Odontology; journal of Nippon Dental College》1989,77(2):701-711
In order to study the clinical significance of IAP and ASP, we have measured serum concentration of IAP and ASP in patients with different cancer types including digestive organs, head and neck. Significantly higher correlation (coefficient of correlation = 0.924) was found between IAP and ASP. IAP and ASP levels were elevated in about 60-80% of cancer from digestive organs except hepatocellular carcinoma, and in about 56-100% of head and neck tumor. There was no correlation between IAP, ASP and various tumor markers (CEA, CA19-9, AFP) in all malignancies except pancreatic cancer. There was positive correlation between CEA and IAP, ASP in pancreatic cancer. IAP and ASP levels were significantly higher in patients with cancer having evidence of disease than the patients with cancer who had no evidence of disease, and so the determination of IAP and ASP was clinically useful for the diagnosis of tumor existence. At the time of diagnosis of recurrence, the levels of IAP and ASP were elevated in about 70% of patients with cancer recurrence. There was a definite relation between IAP, ASP and the gastric cancer stage. In later state (stage III and IV), serum IAP and ASP levels were significantly higher than the levels of stage I and II. In hepatocellular carcinoma without liver cirrhosis, the levels of IAP and ASP were higher than the patients with cirrhosis. The determination of IAP and ASP seems to be useful for monitoring clinical course, judgement of therapeutic effects. 相似文献
106.
Krekmanov L Andersson L Ringqvist M Wilhelmsson B Walker-Engström ML Tegelberg A Ringqvist I 《The International journal of adult orthodontics and orthognathic surgery》1998,13(4):289-298
In a prospective randomized study on treatment of obstructive sleep apnea syndrome, anterior-inferior mandibular osteotomy with the purpose of stretching the suprahyoidal muscle was performed as one of the treatment methods. Ten men aged 20 to 65 years, without cardiovascular or neurologic disease, with normal maxillomandibular relation, and having an apnea index between 5 and 25 were included in the study. After a specially designed osteotomy of the chin, the anterior suprahyoidal muscles were detached, stretched approximately 10 to 12 mm, and sutured. The chin was then placed in its original position and post-operative evaluation was performed. Although there were initial reports of decreased daytime sleepiness and less snoring after surgery, the results after 12 months were discouraging. Somnographic registration (apnea index, apnea/hypopnea index, and oxygen desaturation index) as well as cephalometric analysis failed to show positive results. Hence, suspension of the suprahyoidal muscles as a method of treatment for obstructive sleep apnea syndrome cannot be recommended. 相似文献
107.
L. J. Brady C. Walker G. E. Oxford C. Stewart I. Magnusson W. McArthur 《Oral microbiology and immunology》1996,11(6):371-380
HIV-1 infection is increasing more rapidly among heterosexual women. Relatively limited information is available on HIV-related oral pathoses in these individuals. To gain insight into the type and occurrence of oral lesions in this population, 25 HIV-1 infected women including asymptomatic, symptomatic and AIDS patients were examined clinically and sampled for detection of oral yeast and characterization of their subgingival microbial flora. Sixty percent of the subjects were African-American, with 80% infected via heterosexual contact. Oral candidiasis was the most common nonperiodontal oral lesion, observed in 44% of the patients. Oral yeast was cultured from all women with candidiasis and 76% of the total subjects. Oral hairy leukoplakia was clinically diagnosed in 16% of the subjects. Clinically mild to moderate gingivitis and periodontitis were observed in 84% and 52% of the patients, respectively. Candidiasis and the presence of cultivable yeast were observed in patients with low, intermediate, and high CD4+ T lymphocyte numbers. Plaque samples were collected from each subject and enumerated by predominant cultivable methods, selective media and microscopy. No differences were detected in the microflora associated with seropositive women with existing periodontitis relative to those without periodontitis or to seronegative women with periodontitis. Candidiasis was the most notable oral clinical manifestation in the HIV-1-infected women and may be a useful clinical indicator of early immune dysfunction mediated by HIV-1. 相似文献
108.
109.
Cells infiltrating human periapical inflammatory lesions 总被引:2,自引:0,他引:2
Cells infiltrating human periapical granulomas and cysts were analyzed using cell suspensions. Over 50% of the total cells studied were lymphocytes whilst neutrophils were the next most frequent cell type observed. Two percent of the cells were mast cells. Only a few monocytes/macrophages and natural killer cells were found. More than half of the lymphocytes infiltrating the lesions were T cells, and more than half of the T cells were of the suppressor/cytotoxic (OKT8) phenotype. The OKT4/OKT8 ratio was 0.5. The findings are compared to previous reports and the differences discussed. 相似文献
110.
Bis-dequalinium acetate (BDA), a quaternary ammonium compound, was introduced as a bactericidal and chemotherapeutic agent for endodontic use. This study was undertaken to compare the efficacy of this compound to 5.25% sodium hypochlorite in the cleansing and shaping of root canals. One hundred twenty freshly extracted teeth were divided into three groups. Each group was treated with the aid of the test material; saline solution was used as a control. After completion of the endodontic preparation, a silicone imprint of the canals was performed and the teeth were decalcified. The imprints were examined three-dimensionally to determine the amount of debris and canal configuration due to defective preparation and anatomic variation. No significant difference could be observed between the tested materials with respect to cleanliness and the shape of the canals. At the apical third, however, the BDA-treated canals showed more favorable results with respect to cleanliness. On the basis of the present and previous findings, it was concluded that BDA might be a favorable replacement for sodium hypochlorite as an irrigation solution. 相似文献