首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1960篇
  免费   72篇
  国内免费   26篇
耳鼻咽喉   54篇
儿科学   117篇
妇产科学   66篇
基础医学   149篇
口腔科学   121篇
临床医学   141篇
内科学   376篇
皮肤病学   43篇
神经病学   176篇
特种医学   51篇
外科学   451篇
综合类   27篇
预防医学   28篇
眼科学   55篇
药学   118篇
中国医学   1篇
肿瘤学   84篇
  2023年   16篇
  2022年   21篇
  2021年   38篇
  2020年   27篇
  2019年   20篇
  2018年   25篇
  2017年   27篇
  2016年   51篇
  2015年   85篇
  2014年   95篇
  2013年   108篇
  2012年   151篇
  2011年   161篇
  2010年   76篇
  2009年   66篇
  2008年   103篇
  2007年   132篇
  2006年   111篇
  2005年   157篇
  2004年   117篇
  2003年   105篇
  2002年   91篇
  2001年   42篇
  2000年   42篇
  1999年   46篇
  1998年   12篇
  1997年   16篇
  1996年   13篇
  1995年   13篇
  1994年   8篇
  1993年   11篇
  1992年   12篇
  1991年   16篇
  1990年   5篇
  1989年   7篇
  1988年   8篇
  1987年   6篇
  1986年   4篇
  1985年   2篇
  1984年   3篇
  1983年   2篇
  1982年   1篇
  1974年   2篇
  1972年   2篇
  1970年   1篇
  1967年   1篇
排序方式: 共有2058条查询结果,搜索用时 0 毫秒
61.
European Archives of Oto-Rhino-Laryngology - To compare the local and intracranial complications, migration of the IRS, surgical duration, and quality of life with the subperiosteal pocket...  相似文献   
62.
Although tension-free techniques of hernia repair using synthetic meshes have yielded encouraging results, the best method of inguinal hernia repair is still unclear. The aim of this study was to compare the responses of inflammatory mediators and postoperative pain relief following laparoscopic total extraperitoneal (TEP) hernioplasty, open tension-free mesh hernioplasty (Lichtenstein), posterior preperitoneal mesh hernioplasty (Nyhus procedure), and Bassini procedure. Patients with primary inguinal hernia were randomized in the operating room to undergo one of these repair techniques. Group I comprised 24 patients treated by Lichtenstein procedure; Group II comprised 21 patients treated by Nyhus procedure; Group III comprised 19 patients treated by Bassini procedure; and Group IV comprised 20 patients treated by laparoscopic TEP mesh hernioplasty. Postoperative pain levels following hernia repair were compared by measuring the use of patient-controlled analgesia (PCA) during the 24 hours after surgery. Serum samples withdrawn before surgery and 48 hours after surgery were assayed for C-reactive protein (CRP) content. Patient characteristics, operating time, and operative and early complications were noted. Serum CRP levels rose markedly following Nyhus (184.5 +/- 41.6 mg/L), Lichtenstein (138.4 +/- 72.5 mg/L), and Bassini repair (137.2 +/- 55.9 mg/L) compared with that of patients who underwent TEP mesh hernioplasty (55.5 +/- 41.2 mg/L). There were also significant differences in the postoperative need for analgesics via PCA among patients undergoing Nyhus (382.9 +/- 189.1 mg), Bassini (303.2 +/- 173.7 mg), and Lichtenstein (253.9 +/- 129.3) procedures compared with 196.6 +/- 148.8 mg for the TEP mesh hernioplasty group. Patients in the Lichtenstein group also had significantly less need of analgesics than those in the Nyhus and Bassini groups. In conclusion, TEP mesh hernioplasty is less traumatic and yields less postoperative pain than the Nyhus, Lichtenstein, and Bassini procedures.  相似文献   
63.
PURPOSE: To evaluate the effect of saliva contamination on the microleakage of an etch-and-rinse adhesive and a self-etching adhesive. MATERIALS AND METHODS: Class V cavity preparations at the cementoenamel junction were made on the buccal and lingual surfaces of 40 freshly extracted human molars. The teeth were randomly assigned into two groups for different adhesives: Group I, Single Bond (two-step etch-and-rinse adhesive) and Group II, Futura Bond NR (one-step self-etching adhesive). The adhesive materials were applied according to their manufacturers' recommendations. The specimens were then further subdivided into five subgroups (A-E; n = 8): group A, contamination before adhesive curing; group B, contamination before adhesive curing and re-application of adhesive; group C, contamination after adhesive curing; group D, contamination after adhesive curing and re-application of adhesive; and group E, no contamination (control). Contamination of adhesive surfaces was performed with fresh natural saliva and the saliva was removed by a gentle air blast. The specimens were restored with Z250 hybrid composite. After thermocycling (500x, 5 degrees C to 55 degrees C) and immersion in 0.5% basic fuchsin, the dye penetration was evaluated under a stereomicroscope. Statistical analysis was performed with the Kruskal-Wallis test at p < 0.05. RESULTS: No statistically significant differences were found among the contamination subgroups on the enamel or on the dentin for either group (p > 0.05). There was no significant difference in leakage between Group I and Group II for any subgroup (p > 0.05). CONCLUSION: Contamination of adhesives with saliva before and after adhesive curing did not worsen the microleakage of the two-step etch-and-rinse adhesive Single Bond or the one-step self-etching adhesive Futura Bond NR.  相似文献   
64.
65.
OBJECTIVES: Macrolide-lincosamide-streptogramin B (MLSB) resistance determinants of group A streptococci (GAS) in Ankara, Turkey, were defined for the first time. ISOLATES AND METHODS: A total of 1355 GAS isolates, collected from three different regions of Ankara, were screened for erythromycin resistance. Resistance phenotypes were determined by a triple-disc test, and the gene determinants responsible were determined by PCR. MICs of erythromycin, clindamycin and spiramycin were measured for the resistant isolates, and susceptibility rates to some further antibiotics were determined. RESULTS: Thirty-six isolates (2.6%) were resistant to erythromycin. Of these, 17 (47.2%) expressed macrolide-restricted resistance (M phenotype), while the remainder expressed inducible (16 isolates, 44.4%) or constitutive (three isolates, 8.3%) MLSB resistance. All isolates of the M phenotype harboured the mef(A) gene. Of non-M isolates, 14 harboured erm(A) subclass erm(TR) and five had erm(B) genes. There was a significant relationship between tetracycline resistance and the inducible phenotype (P < 0.05). Macrolide resistance was significantly higher in adults (P < 0.05), and increased more than two-fold in 2002 compared with 2001 (P < 0.05). CONCLUSION: The prevalence of macrolide resistance in GAS is low in Ankara; therefore, routine antimicrobial susceptibility testing against these agents seems unwarranted.  相似文献   
66.
Although hepatitis B has been well studied, there are still aspects of its epidemiology that remain to be clarified. There are many regions with high seroprevalence, particularly in the developing regions of the world, and these regions are known to have different epidemiologic patterns. Nonetheless, there are currently no data on the differences in hepatitis B seroprevalence between urban and rural areas of Turkey. In the present study, therefore, we used 30-cluster sampling to determine and compare the prevalence of hepatitis B in the urban and rural areas of the least developed region of Turkey, the southeastern region. From 2,888 adults living in the region, blood samples were obtained from house visits, and screened for HBsAg, anti-HBs, and anti-HBcIgG. Factors associated with hepatitis B seroprevalence, particularly living in rural areas, were analyzed with multivariate methods. The seroprevalence of HBsAg was 8.2% in the rural and 6.2% in the urban areas. There was a statistically significant difference between urban and rural regions in terms of HBsAg positivity (crude OR: 0.74; 95% CI: 0.55 - 0.98). Exposure to hepatitis B virus (HBV) increased with age both in urban and rural areas. Lower education level was also an important risk factor for hepatitis B seropositivity in urban areas (adjusted OR: 1.66; 95% CI: 1.26 - 2.19) but not in rural ones (adjusted OR: 0.77; 95% CI: 0.36 - 1.69). Familial jaundice history was a statistically significant risk factor for HBsAg positivity in rural areas (adjusted OR: 2.15; 95% CI: 1.30 - 3.56) but not in urban ones (adjusted OR: 1.48; 95% CI: 0.96 - 2.27). This study shows that the prevalence of HBV infection in the southeastern region of Turkey is intermediate among the levels reported for the European region of the World Health Organization.  相似文献   
67.

Background/Aim

The aim of the present study was to investigate the prevalence of obesity-related dermatoses in obese children, and the association between these dermatoses and insulin resistance as well as skin color.

Methods

Obese, overweight, and normal weight children according to body mass index who were followed up and treated in the outpatient clinics were included in the study. Dermatological examinations of the participants were performed, and fasting insulin and glucose levels were checked.

Results

The obese and overweight children were evaluated as the patient group (70 girls, 41 boys, mean age: 12.37 ± 3.14 years). One hundred one healthy children with normal weight were determined as the control group (59 girls, 42 boys, mean age: 12.15 ± 2.43). The first five common dermatoses in the patient group when compared with the control group were keratosis pilaris (KP), striae distensae, hyperhidrosis, acanthosis nigricans (AN), and plantar hyperkeratosis. The first five dermatoses which were positively correlated with formation and insulin resistance were KP, striae distensae, AN, hyperhidrosis, and plantar hyperkeratosis. According to the Fitzpatrick skin scale, we found that the darker the skin color, the higher the probability of AN and KP (OR, 0.298; 95% CI, 0.106–0.834, p = 0.021; OR, 0.306; 95% CI, 0.117–0.796, p = 0.015, respectively).

Conclusion

Some dermatoses associated with obesity and insulin resistance were not found in obese children, or there was no significant association. These results indicate that many skin morbidities may be prevented by preventing and treating obesity and insulin resistance in the early period.  相似文献   
68.
OBJECTIVE: The superior vena cava (SVC) obstruction by malignant diseases is either by direct invasion and compression or by tumour thrombus of the SVC. Whatever is its cause, obstruction of the SVC causes elevated pressure in the veins draining into the SVC and increased or reversed blood flow through collateral vessels. Severity of the syndrome depends on the collateral vascular system development. Therefore, imaging of the collateral veins with variable location and connection is important in determining the extension and management of the disease. Our aims are to describe collateral vessels of the superior vena cava syndrome (SVCS) related with the malignant diseases and to assess the ability of multi-detector row CT with multiplanar and 3D volume rendering techniques in determining and describing collateral circulations. MATERIALS AND METHODS: We present CT angiography findings of seven patients with small cell carcinoma of the lung (n = 2), squamous cell carcinoma of the lung (n = 3), Hodgkin disease of the thorax (n = 1), and squamous cell carcinoma of the oesophagus (n = 1). The patients received contrast-enhanced CT scans of the chest and abdomen on a multi-detector row CT during breath holding at suspended inspiration. RESULTS: CT images revealed the cause and level of the SVC obstruction in all patients with axial and multiplanar reconstructed images. The SVC showed total obstruction in five patients and partial obstruction in two patients. The most common experienced collateral vessels were azygos vein (6), intercostal veins (6), mediastinal veins (6), paravertebral veins (5), hemiazygos vein (5), thoracoepigastric vein (5), internal mammary vein (5), thoracoacromioclavicular venous plexus (5), and anterior chest wall veins (5). While one case showed the portal-systemic shunt, V. cordis media and sinus coronarius with phrenic veins were enlarged in two cases, and the left adrenal vein was enlarged in a patient. In one case, the azygos vein with reversed blood flow was drained into both inferior vena cava and hemiazygos vein with the left renal vein. CONCLUSION: Multi-detector row CT with multiplanar and 3D imaging is an effective tool in evaluation of the SVCS and has a greater advantage than the other imaging techniques. 3D volume rendering is a useful technique in determining and describing collateral circulations in addition to the primary disease process.  相似文献   
69.
70.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号