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   11264篇
  免费   486篇
  国内免费   77篇
耳鼻咽喉   258篇
儿科学   480篇
妇产科学   385篇
基础医学   1010篇
口腔科学   406篇
临床医学   926篇
内科学   2642篇
皮肤病学   186篇
神经病学   679篇
特种医学   503篇
外科学   2256篇
综合类   254篇
一般理论   3篇
预防医学   451篇
眼科学   245篇
药学   618篇
中国医学   36篇
肿瘤学   489篇
  2024年   7篇
  2023年   107篇
  2022年   230篇
  2021年   390篇
  2020年   202篇
  2019年   274篇
  2018年   322篇
  2017年   236篇
  2016年   366篇
  2015年   423篇
  2014年   528篇
  2013年   610篇
  2012年   776篇
  2011年   779篇
  2010年   467篇
  2009年   409篇
  2008年   773篇
  2007年   868篇
  2006年   850篇
  2005年   780篇
  2004年   663篇
  2003年   539篇
  2002年   476篇
  2001年   86篇
  2000年   81篇
  1999年   68篇
  1998年   62篇
  1997年   44篇
  1996年   54篇
  1995年   29篇
  1994年   21篇
  1993年   22篇
  1992年   23篇
  1991年   20篇
  1990年   24篇
  1989年   31篇
  1988年   20篇
  1987年   19篇
  1986年   18篇
  1985年   18篇
  1984年   8篇
  1983年   11篇
  1982年   6篇
  1980年   6篇
  1979年   7篇
  1978年   8篇
  1974年   5篇
  1973年   9篇
  1972年   7篇
  1971年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.

Background

The purpose of this study is to investigate the inter- and intraobserver reliability of Crowe and Hartofilakidis classifications in the assessment of developmental dysplasia of the hip in adult patients.

Materials and methods

Two consultant orthopedic surgeons classified 141 dysplastic hips on 103 standard anterior–posterior pelvis radiographs according to the Crowe and Hartofilakidis classifications. Assessments were performed in random order by each observer on two separate occasions, at least 4?weeks apart. Kappa statistics were used to establish a relative level of agreement between observers for the two readings and between separate readings by the same observer.

Results

At the first readings, interobserver reliability analysis revealed kappa coefficient of 0.71 for the Crowe classification and 0.54 for the Hartofilakidis classification. At the second reading, the kappa coefficient was 0.72 for the Crowe classification and 0.75 for the Hartofilakidis classification. Intraobserver reliability analysis revealed kappa coefficients of 0.71 for the Crowe and 0.80 for the Hartofilakidis classification for observer A, and 0.76 and 0.70 for observer B.

Conclusions

In conclusion, we have found substantial inter- and intraobserver agreement for Crowe classification and substantial to moderate agreement for Hartofilakidis classification in this study. Both classification systems assess the different aspects of developmental dysplasia of hip in adults. Each system has advantages and disadvantages. We suggest using both of these classifications together to increase the accuracy.  相似文献   
92.
Protective effect of quercetin on renal ischemia/reperfusion injury in rats   总被引:5,自引:0,他引:5  
BACKGROUND: There is increasing evidence to suggest that toxic oxygen radicals play a role in the pathogenesis of ischemia/reperfusion (I/R) injury in the kidney. The aim of this study was to evaluate whether quercetin, an oxygen free radical scavenger, protects kidney tissue. METHODS: A renal I/R injury was induced by a left renal pedicle occlusion by ischemia for 45 min, followed by 60 mins of reperfusion with contralateral nephrectomy in rats. The rats were pretreated intraperitoneally with a quercetin suspension (50 mg/kg) 60 min before the ischemia induction. Thiobarbituric acid reactive substances (TBARS), protein carbonyl content, tumor necrosis factor alpha (TNF-alpha), reduced glutathione (GSH) levels, myeloperoxidase (MPO) catalase (CAT) and superoxide dismutase (SOD) activities were determined in renal tissue. RESULTS: There were 3 groups of rats, the control group, the I/R group and the I/R+Q group. Our results indicate that TBARS, TNF-alpha levels, MPO activity and protein carbonyl content were significantly higher in the I/R group than those in the control group (p<0.05, p<0.01, p<0.01 and p<0.01, respectively). Quercetin administration significantly decreased these parameters (p<0.05, p<0.01, p<0.05 and p<0.01, respectively). GSH levels, SOD, and CAT activities significantly decreased after I/R injury when compared to the control group (p<0.01, p<0.05 and p<0.01, respectively). Quercetin treatment significantly increased GSH levels and activities of these enzymes when compared to the I/R group (p<0.05, p<0.01, p<0.05, respectively). CONCLUSIONS: These results suggest that quercetin reduces renal oxidative injury and facilitates repair. Quercetin can have a role in a renoprotective therapeutic regimen.  相似文献   
93.
An inguinal and perianal localization of Fournier's gangrene (FG) in a 15-month-old boy as a complication of the varicella infection is discussed. This is the first presentation of the disease as a complication of the varicella rashes. There were already 57 pediatric FG cases resulting from other causes that had been presented in the medical literature.  相似文献   
94.
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   
95.
Aim: Erectile dysfunction may be observed in up to 80% of patients with Peyronie's disease. An objective evaluation of the erectile function is attempted to work out in patients with Peyronie's disease. Methods: Penile deformity, sexual function and penile vascular status were analyzed in 123 patients with Peyronie's disease, who had not received any pertinent treatment. Results: Penile deformity, palpable plaque and pain on erection were seen in 112 (91%), 97(78.8%) and 27 (21.9%) of the 123 patients, respectively. Of the 76 patients evaluated by color Doppler ultrasounography, veno-occlusive dysfunction as the vascular component for erectile dysfunction was found in 17 (22.3%), arterial insufficiency in 10(13.1%) and a mixed picture in 23 (30.2%). Conclusion: The documentation of penile erectile function and the determination of the vascular status using color Doppler ultrasonography can guide the appropriate therapeutic choice.  相似文献   
96.

Background

Airway surfactant is impaired in cystic fibrosis (CF) and associated with declines in pulmonary function. We hypothesized that surfactant dysfunction in CF is due to an excess of cholesterol with an interaction with oxidation.

Methods

Surfactant was extracted from bronchial lavage fluid from children with CF and surface tension, and lipid content, inflammatory cells and microbial flora were determined. Dysfunctional surfactant samples were re-tested with a lipid-sequestering agent, methyl-β-cyclodextrin (MβCD).

Results

CF surfactant samples were unable to sustain a normal low surface tension. MβCD restored surfactant function in a majority of samples.Mechanistic studies showed that the dysfunction was due to a combination of elevated cholesterol and an interaction with oxidized phospholipids and their pro-inflammatory hydrolysis products.

Conclusion

We confirm that CF patients have impaired airway surfactant function which could be restored with MβCD. These findings have implications for improving lung function and mitigating inflammation in patients with CF.  相似文献   
97.
The aim of this study was to present our experiences with, as well as the factors that affect, the treatment and outcome of patients with neonatal gastrointestinal perforations (GIPs). Thirty-eight newborn cases that were operated on for GIP in our hospital’s tertiary newborn intensive care unit between January 2005 and December 2015 were retrospectively evaluated. The patients were divided into the two following groups: group 1, perforations related to necrotizing enterocolitis (NEC), and group 2, non-NEC perforations. In total, 38 patients (16 males, 22 females) participated in this study. The perforations were related to NEC in 12 patients (group 1; 31.6 %), and the other 26 patients (group 2; 68.4 %) were classified as non-NEC perforation cases. The incidence of neonatal GIP was 0.53 % in all newborn patients, while the incidence of perforation in NEC cases was 20 %. Of all patients, 25 (65.7 %) were premature. Non-NEC pathologies were the most common cause of GIP (68.4 %) and included stomach perforation related to a nasogastric catheter (n = 5), volvulus (n = 4), intestinal atresia (n = 3), esophageal atresia and tracheoesophageal fistula (n = 2), cystic fibrosis (n = 2), Hirschprung’s disease (n = 2), appendicitis (n = 2), congenital stomach anterior wall weakness (n = 1), duplication cyst (n = 1), invagination (n = 1), incarcerated inguinal hernia (n = 1), and idiopathic causes (n = 2). Primary surgical repair was performed in all cases without a conservative approach. The mortality rate related to GIP in newborn cases was 47.3 %. While the mortality rate in group 1 was 66.6 %, it was statistically insignificantly lower in group 2 (38.4 %) (p > 0.05). In group 1, the mortality rate of those with intestinal and colorectal perforations was 45.6 and 20 %, respectively (p > 0.05). Non-NEC pathologies are the most frequent causes of GIP in newborns, and primary surgical repair is the primary treatment choice for neonatal GIP. However, GIP remains one of the most significant causes of mortality in newborns. While the prognosis for neonatal colon perforation is good, that for stomach and jejunoileal perforations is worse.  相似文献   
98.

Introduction

One of the complications of laparoscopic surgery is incisional hernia at the port trocar site. It is a rare complication, with a reported incidence varying between 0.65% and 2.8%, and it is documented in both adults and children.

Case presentation

An obese 62-year-old woman underwent a laparoscopic mini gastric bypass for body weight reduction at another hospital. On the third post-operative day, she developed abdominal pain with vomiting and was admitted to our hospital. Imaging studies confirmed a small bowel loop obstruction at the lateral 12mm trocar site and the patient was operated on immediately. The viability of the entrapped bowel was confirmed at the trocar site opening, the bowel loop was returned into the abdominal cavity and the defect was closed. Two days later, the patient was discharged in good condition.

Discussion

Trocar site or port site hernia is defined as an incisional hernia which occurs after minimal invasive surgery, at the trocar site incision. Following bariatric surgery its reported incidence is 1% - 1.6%. Its cause is multi-factorial, including obesity and old age, the size and site of the inserted trocar and the angle of insertion, and excessive manipulations. Although there is no clear consensus on closure at port sites, it is recommended that fascial defects of larger than 10mm in adults and 5mm in children should be closed.

Conclusion

Trocar site hernia is a rare complication of laparoscopic procedures, and one that can be minimized. Viscus entrapment in a port site hernia should be suspected during the post-operative period whenever the patient presents with abdominal distension, pain and vomiting since, particularly in the case of bariatric surgery, the findings on physical examination may be inconclusive, due to obesity.
  相似文献   
99.
Purpose: Anastomotic leaks following intestinal operations may cause devastating effects on patients. Ischemia may also occur at the intestinal walls in the presence of strangulations. In this study, we examined the effects of human recombinant (Hr)-epidermal growth factor (EGF) given at a single intramural dose into the intestinal walls and daily intraperitoneal cavity on ischemia and the healing process of anastomosis. Materials and Methods: Sixteen male New Zeland white rabbits were randomly divided into four groups (n = 4 in each group). In Group 1, two different segments of ileum were identified and, then, transected and the free ends were sutured each other. In the other groups, ischemia was induced by ligating the mesenteric vascular arcade. After the ischemic induction, Group 2 received intramural injections of %0.9 saline, Group 3 received intramural injections of a single dose of EGF, and Group 4 received intramural and intraperitoneal injections of EGF. Bursting pressures and tissue hydroxyproline levels were analyzed. Necrosis, fibroblastic activity, collagen deposition and neovascularization were also studied. Results: The mean levels of bursting pressures in Group 4 (148.6 ± 25.3 mmHg) were higher than Group 2 (70 ± 21.5 mmHg) (p = 0.001). The mean level of bursting pressures was not statistically significant between Group 1 (170.1 ± 35 mmHg) and Group 4 (p = 0.073). Hydroxyproline levels in Group 2 were lower than Groups 3 and 4. There was a statistically significant difference in the mucosal ischemia, mucosal healing and degree of adhesion, but not in the mural anastomotic healing among the groups. Conclusions: Intramural injection with daily intraperitoneal administration of low-dose EGF enhances the bursting pressure and collagen accumulation in ischemic anastomosis, improving many histological variables associated with ischemic intestinal anastomosis.  相似文献   
100.
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