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   767篇
  免费   39篇
  国内免费   8篇
耳鼻咽喉   10篇
儿科学   67篇
妇产科学   26篇
基础医学   69篇
口腔科学   37篇
临床医学   79篇
内科学   182篇
皮肤病学   16篇
神经病学   51篇
特种医学   19篇
外科学   136篇
综合类   19篇
预防医学   28篇
眼科学   13篇
药学   30篇
中国医学   1篇
肿瘤学   31篇
  2024年   1篇
  2023年   2篇
  2022年   9篇
  2021年   15篇
  2020年   10篇
  2019年   18篇
  2018年   29篇
  2017年   14篇
  2016年   11篇
  2015年   24篇
  2014年   28篇
  2013年   53篇
  2012年   47篇
  2011年   51篇
  2010年   40篇
  2009年   40篇
  2008年   60篇
  2007年   74篇
  2006年   81篇
  2005年   63篇
  2004年   47篇
  2003年   29篇
  2002年   27篇
  2001年   2篇
  2000年   4篇
  1999年   5篇
  1998年   3篇
  1997年   4篇
  1995年   2篇
  1994年   1篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1990年   3篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1986年   3篇
  1985年   2篇
  1983年   1篇
  1979年   1篇
  1976年   1篇
  1969年   1篇
排序方式: 共有814条查询结果,搜索用时 0 毫秒
81.
AIM: To identify the role of anti-pancreatic antibody (PAB) in the diagnosis of inflammatory bowel diseases (IBD) among Turkish patients, and its frequency in firstdegree relatives.METHODS: PAB and anti-Saccharomyces cerevisiae (ASCA) were examined in serum samples of 214 subjects including patients with Crohn’s disease (CD, n = 64), ulcerative colitis (UC, n = 63), first-degree relatives of patients with CD (n = 25), first-degree relatives of patients with UC (n = 28),and a control group with gastrointestinal symptoms other than (IBD) (n = 34) by indirect immunofluorescence Positivity of PAB and ASCA was compared in terms of Vienna classification, disease activity and medications used.RESULTS: In terms of PAB positivity, no difference was found between patients with CD (14.1%) and UC (7.9%) however, significant difference was observed between patients with CD and subjects in the control group (P < 0.05). No difference was found between patients with CD and their relatives in terms of ASCA positivity, whereas a significant difference was found between other groups (P < 0.001). Compared to ASCA, the sensitivity of the PAB was 19% (7/37), its specificity was 93% (25/27), positive predictive value was 77% (7/9) and negative predictive value was 45% (25/55). ASCA was found with significantly higher prevalence in patients with CD activity index > 150 (P < 0.05).CONCLUSION: PAB is valuable in the diagnosis of IBD rather than CD, but cannot be used alone for diagnostic purposes. PAB is not superior to ASCA in CD diagnosis and in detecting CD among relatives of patients with CD.  相似文献   
82.
To evaluate the effects of nicorandil in a rat kidney model of partial unilateral ureteral obstruction (PUUO). Thirty male rats were randomly divided into three groups as follows: (1) Group 1 (Sham-control), ureters of the rats were manipulated but not ligated; (2) Group 2 (PUUO-untreated), PUUO was performed with two-thirds of the left ureter embedded in the psoas muscle; and (3) Group 3 (PUUO-nicorandil treated). After PUUO was established, nicorandil (15 mg/kg/day) was administered by gastric lavage for 21 days to determine its effects on PUUO-induced histopathological-, functional-, and oxidative stress-induced changes. The serum levels of blood urea nitrogen and creatinine were reduced in Group 3. The level of urinary albumin and the ratio of urinary protein/creatinine were increased in the kidneys of Group 2 but decreased in Group 3. Malondialdehyde value was decreased in Group 3 compared with Group 2. Antioxidant enzyme activities (catalase, superoxide dismutase, and glutathione peroxidase) were decreased in Group 2. Nicorandil treatment caused an increase in these enzyme activities. In Group 3, leukocyte infiltration and tubular dilatation were significantly reduced. Other parameters, such as degeneration of tubular epithelium and fibrosis, also showed a marked improvement in Group 3. Expression of inducible nitric oxide synthase in Group 2 and expression of endothelial nitric oxide synthase in Group 3 were significantly elevated. Nicorandil can inhibit renal tubular damage and tubulointerstitial fibrosis by reducing the effects of oxidative stress after PUUO.  相似文献   
83.
Flow cytometric DNA studies were performed on cell suspensions of biopsy specimens from gastric tumors and neutral gastric mucosa in 18 patients with gastric cancer and 9 patients with gastric polyps. In cancer, aneuploidy was found in two tumors in the antral and five in the body part of the stomach (39%). The mean DNA index for aneuploid cancers was 1.57. In patients with aneuploid carcinomas three biopsy specimens from uninvolved mucosa also showed aneuploidy. In diploid carcinomas in the antral part of the stomach, the proliferative index (PI) was increased when compared with that of antral mucosa in controls (p < 0.05). Increased PI was found in uninvolved mucosa in aneuploid carcinomas of the body part of the stomach when compared with that in diploid carcinomas (p < 0.001). In uninvolved body mucosa in aneuploid carcinomas of the body part significantly reduced levels of acid-β-glucuronidase (p < 0.0001) were found when compared with diploid carcinomas. No polyps showed aneuploidy. and the PI in biopsy specimens from patients with gastric polyps did not differ from that in controls.  相似文献   
84.

Background

Iodine deficiency (ID) during the fetal and neonatal periods can lead to neonatal hypothyroidism. This study was conducted to evaluate the effect of ID on the thyroid hormone level of newborns living in Turkey.

Methods

Between 1998 and 2013, 71 newborns with a urinary iodine concentration <100 μg/L were recruited into the study. Data on thyroid volume, free triiodothyronine (fT3), free thyroxine (fT4), thyroid stimulating hormone (TSH), and thyroglobulin (Tg) were collected from all newborns, and on breast milk iodine from their mothers. Infants who were classified as having congenital hypothyroidism (TSH >40 mU/L and fT4 <8.5 pmol/L) were treated with levothyroxine (n=26, T group), while the remaining infants remained untreated (n=45, UT group). Thyroid hormones were subsequently measured 7-14 days later in a sub-sample of both treated and untreated infants.

Results

The average values at the time of admission were as follows [median (min-max)]. fT3: 5.0 (2.8-7.1) pmol/L, fT4: 7.7 (0.13-19.1) pmol/L, TSH: 75 (14-426) mU/L, Tg: 464 (226-1100) ng/mL, urinary iodine concentration (UIC): 30 (0-61) μg/L, breast milk iodine levels: 21 (10-150) μg/L, thyroid ultrasound (USG): 1.10 (0.24-1.95) mL for the T group; and fT3: 5.7 (1.7-12.7) pmol/L, fT4: 16.2 (9.9-33.5) pmol/L, TSH: 5.4 (0.63-41.8) mU/L, Tg: 171 (15-2124) ng/mL, UIC: 39 (0-90) μg/L, breast milk iodine levels: 47 (10-120) μg/L, thyroid USG: 0.75 (0.35-1.72) mL for the UT group. A significant difference was found between groups in respect to fT3, fT4, TSH and Tg levels. No significant difference in thyroid ultrasonography, UIC, and breast milk iodine levels was found between the two groups. The Tg levels of 50 out of 71 patients were measured, 40 (80%) of whom had Tg levels above the normal range (101 ng/mL).

Conclusions

In our country, despite the use of iodized salt, congenital hypothyroidism due to ID remains a problem. The Tg level of newborns can be used as a good indicator of ID.
  相似文献   
85.
Endobronchial metastases: a clinicopathological analysis   总被引:1,自引:0,他引:1  
OBJECTIVE: It is important to distinguish endobronchial metastases (EBM) from both primary lung cancers and benign lesions, as treatment will differ. The clinicopathological characteristics of EBM cases were documented to see whether any distinguishing features exist. METHODOLOGY: Histological cases diagnosed as EBM in the pathology laboratory of a tertiary hospital were re-evaluated. Symptoms, primary tumour sites, recurrence interval, radiological and bronchoscopic features, and histopathological properties were assessed. RESULTS: There were 18 cases (eight female, 10 male) with EBM. All were diagnosed by bronchoscopic bronchial biopsy. The primary tumour sites were: colorectal (4), breast (3), renal (3), lymphoma (3), rhabdomyosarcoma (2), bladder (1), thyroid (1) and malignant melanoma (1). The mean time from the diagnosis of the primary tumour to their presentation was 3.89+/-1.09 (range, 0--19) years. In five patients, EBM was diagnosed synchronously with their extra pulmonary primary tumour. Two had other metastatic sites. Haemoptysis and cough were the more common symptoms. Interestingly, three patients were asymptomatic. There was no predilection for a particular airway segment to be involved but a predilection for the upper lobe existed. Endoscopic appearance was polypoid in 10 cases and mucosal infiltration in the remainder. Histopathological examination revealed epithelial tissue at the surface of the tumour in nine cases and four of these were metaplastic. In all but one there was inflammation, mainly lymphocytic. Necrosis was present in 10 cases and bleeding was seen in four. There were no statistically significant differences between the level of lymphocytic inflammation and other clinicopathological parameters. CONCLUSION: EBM is a rare condition that can be synchronous or occur late. Surprisingly, it can be asymptomatic. It is usually found in the upper lobes. Lymphocytic inflammation is a common histopathological finding. There is need for further studies to clarify the clinical importance of EBM.  相似文献   
86.
87.
88.
Erythema and scarring are among the most common complications of severe inflammatory acne. In this study, we aimed to share our experience with pro‐yellow laser and document the efficacy and safety of this treatment in postacne erythema and scarring. The study included 40 patients, 24 (60%) females, and 16 (40%) males with a mean age of 29.5 ± 8.16 (min. 18 years, max. 57 years). The pro‐yellow laser was applied to all patients as a single session with irradiation of 22 J/cm2. Improvement in postacne erythema and scars were evaluated after the treatment. The study included 40 patients, 24 patients (60%) were females and 16 patients (40%) were males with the mean age of 29.5 ± 8.16 (ranged between 18 and 57 years old). A total of 21 patients (52.5%) had good improvement (51%‐75% regression), 10 patients (25%) had excellent improvement (76%‐100% regression), and a moderate improvement (26%‐50%) was detected in 9 patients (22.5%). Also, there were mild improvement (1%‐25%) in 20 patients (76.9%) and a moderate improvement (26%‐50%) in 6 patients (23.1%). We found that pro‐yellow laser is highly effective in the treatment of postacne erythema, while its effectiveness was mild to moderate in atrophic acne scars. Also, it has been observed that the pro‐yellow laser system can be used safely immediately after cessation of systemic isotretinoin treatment.  相似文献   
89.
90.
The hypothesis, a relationship between gingival tissue platelet activating factor (PAF) levels and healing after periodontal surgery, was tested by measuring PAF levels in gingival tissues collected from sites that had undergone flap surgery and guided tissue regeneration (GTR) or flap surgery alone. Using a split-mouth design, 20 intrabony defects were randomly assigned to treatment with flap surgery and GTR (group 1) or with flap surgery alone (group 2). Gingival tissue samples were obtained at surgery (baseline) and at 6-month follow-up evaluation visit. One half of each sample was used for analysis of PAF levels by high-performance liquid chromatography, and the other half of the sample was used for histomorphometric analysis that included measurements of number and diameter of blood vessels. PAF levels and diameter of blood vessels were significantly decreased (p < 0.01), and the number of blood vessels was significantly increased (p < 0.05) in both groups after 6 months compared to the baseline values. Postoperative number of blood vessels were significantly higher in group 1 (p < 0.05), whereas there was no significant difference in postoperative PAF levels between the two groups (p > 0.05). Based on the reported results, it is suggested that a decrease in gingival PAF levels might be found after conventional and regenerative periodontal surgery.  相似文献   
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