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   11294篇
  免费   488篇
  国内免费   80篇
耳鼻咽喉   258篇
儿科学   480篇
妇产科学   385篇
基础医学   1012篇
口腔科学   406篇
临床医学   931篇
内科学   2654篇
皮肤病学   185篇
神经病学   687篇
特种医学   510篇
外科学   2261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   619篇
中国医学   36篇
肿瘤学   485篇
  2024年   7篇
  2023年   107篇
  2022年   231篇
  2021年   392篇
  2020年   204篇
  2019年   274篇
  2018年   322篇
  2017年   237篇
  2016年   367篇
  2015年   425篇
  2014年   536篇
  2013年   617篇
  2012年   778篇
  2011年   780篇
  2010年   467篇
  2009年   412篇
  2008年   770篇
  2007年   873篇
  2006年   851篇
  2005年   781篇
  2004年   667篇
  2003年   543篇
  2002年   478篇
  2001年   87篇
  2000年   80篇
  1999年   67篇
  1998年   60篇
  1997年   41篇
  1996年   51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 13 毫秒
71.
72.

Purpose

The aim of this study was to investigate the effects of iloprost (IL) on ischemia-reperfusion injury in a rodent model.

Materials and methods

Twenty-four Wistar Albino rats were randomized into four groups (n = 6). Laparotomy was performed in all groups under general anesthesia. Only laparotomy was applied in group S (Sham). Ischemia-reperfusion group (group I/R) underwent ischemia and reperfusion performed by clamping and declamping of the infrarenal abdominal aorta for 120 min. The iloprost group (group IL) received intravenous infusion of IL 0.5 ng/kg/min, without I/R. Group I/R + IL received intravenous infusion of IL 0.5 ng/kg/min immediately after 2 h period of ischemia. At the end of the reperfusion period, all rats were killed under anesthesia and skeletal muscle samples of lower extremity were harvested for biochemical and histopathologic analyses.

Results

Tissue levels of endothelial nitric oxide were significantly higher in I/R groups than those in groups S and IL. The heat shock protein 60 levels were higher in group I/R than the other groups. But the heat shock protein 60 levels in group I/R + IL were found to be similar with the groups S and IL. Malondialdehyde levels were significantly higher in group I/R. On the other hand, in group I/R + IL, malondialdehyde levels were higher than those in groups S and IL but lower than those in group I/R. Superoxide dismutase (SOD) enzyme activities were found to be significantly lower in group I/R than the other groups. Also in group I/R/I, the SOD enzyme activities were higher than those in group I/R. But, in group I/R + IL, SOD levels were found to be higher than those in group I/R but lower than those in groups S and IL.

Conclusions

These results indicate that IL has protective effects on I/R injury in skeletal muscle in a rodent model.  相似文献   
73.

Background and objectives

Laryngoscopy and intubation can cause hemodynamic response. Various medications may be employed to control that response. In this study, we aimed to compare the effects of dexmedetomidine, fentanyl and esmolol on hemodynamic response.

Method

Ninety elective surgery patients who needed endotracheal intubation who were in American Society of Anesthesiology I–II group and ages between 21 and 65 years were included in that prospective, randomized, double‐blind study. Systolic, diastolic, mean arterial pressures, heart rates at the time of admittance at operation room were recorded as basal measurements. The patients were randomized into three groups: Group I (n = 30) received 1 μg/kg dexmedetomidine with infusion in 10 min, Group II (n = 30) received 2 μg/kg fentanyl, Group III received 2 mg/kg esmolol 2 min before induction. The patients were intubated in 3 min. Systolic, diastolic, mean arterial pressures and heart rates were measured before induction, before intubation and 1, 3, 5, 10 min after intubation.

Results

When basal levels were compared with the measurements of the groups, it was found that 5 and 10 min after intubation heart rate in Group I and systolic, diastolic, mean arterial pressures in Group III were lower than other measurements (p < 0.05).

Conclusions

Dexmedetomidine was superior in the prevention of tachycardia. Esmolol prevented sytolic, diastolic, mean arterial pressure increases following intubation. We concluded that further studies are needed in order to find a strategy that prevents the increase in systemic blood pressure and heart rate both.  相似文献   
74.

Background

Intragastric band migration is an unusual but major complication of gastric banding. We review our experience with endoscopic removal of eroded gastric bands.

Methods

We retrospectively evaluated the cases of 110 morbidly obese patients who underwent adjustable gastric banding between 2005 and 2012 to identify those who experienced band erosion. To remove the migrated band, we used an endoscopic approach with a Gastric Band Cutter.

Results

Band or tube erosion occurred in 14 patients (12.7%). The median time interval from the initial gastric band placement to the diagnosis of band erosion was 32 (range 18–52) months. Upper abdominal pain, port site infection, loss of restriction and weight regain were the most common symptoms. We used the Gastric Band Cutter to remove the band endoscopically. It was able to cut the band successfully in all but 1 patient, in whom twisting of the cutting wire required conversion from endoscopy to laparotomy. In 2 patients, the band, after being cut, was locked in the gastric wall and required laparotomic removal. In 1 patient, we performed surgery for intragastric penetration of the connecting tube broken close to the band.

Conclusion

The Gastric Band Cutter was successful in dividing the band in all but 1 patient, although we could not always complete the procedure endoscopically. Endoscopic removal seems to be effective and safe for band erosion.  相似文献   
75.

Background and Objectives:

In this study, we evaluated the safety and efficacy of using the LigaSure sealing system (Valleylab, Boulder, Colorado) for laparoscopic decortication of symptomatic hilar renal cysts.

Methods:

Seventeen patients underwent laparoscopic decortication of hilar renal cysts with the LigaSure system. Our study included only symptomatic, Bosniak type 1, simple and symptomatic renal cysts. The operative route, transperitoneal or retroperitoneal, was planned according to the location confirmed by computed tomography. The patients'' symptoms were preoperatively and postoperatively evaluated by the Wong-Baker visual pain scale. Operative measures and radiologic outcomes were prospectively evaluated.

Results:

The mean age of the patients was 56.4 years, and the mean follow-up period was 12.5 months. Preoperative computed tomography showed only a single cyst in 15 patients (88.2%) and showed two separate cysts in 2 cases (11.8%). The cysts were located in the perihilar region close to the vascular structure in all patients. A transperitoneal approach was used in 9 patients, and a retroperitoneal approach was used in 8 patients. The mean operative time and hospitalization time were 56.4 minutes and 1.2 days, respectively. Minor complications were observed in 3 patients. Symptomatic and radiologic success rates of 94.2% and 100%, respectively, were achieved.

Conclusion:

Laparoscopic decortication of symptomatic hilar renal cysts—first reported in the literature in this study—using the LigaSure sealing system is feasible, effective, and safe, even if the cyst is located in the perihilar area.  相似文献   
76.
Supernumerary testis or polyorchidism is a rare congenital anomaly with about 200 reported cases in the literature. It may be associated with cryptorchidism, testicular torsion and neoplasms. Ultrasonography and magnetic resonance imaging are effective noninvasive methods of accurately detecting polyorchidism. In most cases, ultrasonography is diagnostic and magnetic resonance imaging plays confirmatory role by providing additional information if complicated with neoplasia. We report a case of 16‐year‐old man with right supernumerary testis associated with adenomatous hyperplasia of the rete testis, its sonographic and magnetic resonance imaging findings and management.  相似文献   
77.

Purpose

Taurine, the major intracellular free amino acid found in high concentrations in mammalian cells, is known to be an endogenous antioxidant and a membrane-stabilizing agent. It was hypothesized that taurine may be effective in reducing ischemia–reperfusion injury after lung transplantation and an experimental study was conducted in a rat model.

Methods

The number of Sprague–Dawley rats used in the study was 35. Animals were randomized into five groups of 7 rats each, including control, donor I, donor II, ischemia–reperfusion injury, and treatment groups. All animals were exposed to the same experimental conditions in the preoperative period. Rats were fixed in a supine position after the induction. After the rats were shaved, a left pneumonectomy was performed following sternotomy in control, donor I, and donor II groups. The harvested grafts in donor I and donor II groups were transplanted to the rats of the ischemia–reperfusion group and treatment group, respectively. However, taurine was administered intraperitoneally for 3 days before the harvesting procedure in donor II. All harvested lungs were kept in a Euro-Collins solution at +4 °C for 24 h in a half-inflated manner. After harvesting and transplantation, lungs were sampled for histopathological and biochemical analysis.

Results

Malondialdehyde and superoxide dismutase, glutathione peroxidase, and catalase levels were lower in the treatment group than the other groups (p < 0.05). Histopathological findings were better in treatment group than the ischemia–reperfusion group (p < 0.05).

Conclusion

It was demonstrated that donor treatment with taurine resulted in preservation of transplanted lung tissue in respect to histopathological and biochemical findings.  相似文献   
78.

Purpose

Both parenteral and enteral glutamine have shown beneficial effects in sepsis and ischemia/reperfusion-induced acute lung injury (ALI). Oleic acid (OA) has been used to induce ALI in experimental studies. In this study, we investigated the effects of pretreatment of a bolus dose of enteral glutamine on ALI induced by OA in rats.

Methods

Twenty-eight adult female Sprague–Dawley rats weighing 240–300 g were divided into four groups, 7 in each. Group I and group II received normal saline for 30 days, group III and group IV received glutamine at a dose of 1 g/kg for 10 days by gavage, and in group II and group IV 100 mg/kg OA was administered i.v. Histopathological examination of the lung was performed with light and electron microscopy. Levels of protein carbonyl, malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase levels were measured in tissue samples. Levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and total tissue oxidant status and total tissue antioxidant status were measured in serum samples.

Results

Light microscopy showed that the total lung injury score of group IV was significantly lower than group II. Change in thickness of the fused basal lamina was not significantly different in groups II and IV under electron microscopy. TNF-α, IL-6, and IL-10 serum levels were higher in group II when compared to group I and significantly attenuated in group IV.

Conclusion

Pretreatment with a bolus dose of enteral glutamine minimized the extent of ALI induced by OA in rats.  相似文献   
79.

Background

The rotator cuff plays a significant role in the static and dynamic stability of the glenohumeral joint. Rotator cuff tears may occur after shoulder dislocations, whether in younger athletes or older patients with age-related tendon degeneration. Untreated tears may cause persistent pain, dysfunction, instability, and degenerative changes. A thorough understanding of when to look for rotator cuff tears after shoulder dislocations and how best to manage them may decrease patients’ pain and improve function.

Questions/purposes

We systematically reviewed the available literature to better understand (1) when a rotator cuff tear should be suspected after a dislocation, (2) whether surgical or nonsurgical approaches result in better scores for pain and satisfaction in patients with rotator cuff tears resulting from shoulder dislocations, and (3) whether intraarticular lesions, rotator cuff tears, or both should be addressed when surgery is performed.

Methods

We systematically searched MEDLINE®, CINAHL, and EMBASE for studies published from 1950 to 2012. We included studies reporting outcomes after treatment in patients with rotator cuff tears and shoulder dislocations. We excluded case reports, studies without any treatment, and studies about patients treated with arthroplasty. Five Level III and six Level IV studies were ultimately selected for review.

Results

Patients with persistent pain or dysfunction after a shoulder dislocation often had a concomitant rotator cuff tear. Surgical repair resulted in improved pain relief and patient satisfaction compared to nonoperative management. Repair of the rotator cuff, along with concomitant capsulolabral lesions, helped restore shoulder stability. While these findings are based on Level III and IV evidence, better long-term studies with larger cohorts are needed to strengthen evidence-based recommendations.

Conclusions

Persistent pain and dysfunction after a shoulder dislocation should prompt evaluation of the rotator cuff, especially in contact or overhead athletes, patients older than 40 years, or those with nerve injury. Surgery should be considered in the appropriately active patient with a rotator cuff tear after dislocation. While the current literature suggests improved stability and function after surgical repair of the rotator cuff, higher-quality prospective studies are necessary to make definitive conclusions.  相似文献   
80.

Background

After receiving a living donor liver transplant (LDLT), an incisional hernia is a potentially serious complication that can affect the patient’s quality of life. In the present study we evaluated surgical hernia repair after LDLT.

Materials and methods

Medical records of patients who underwent surgery to repair an incisional hernia after LDLT in Turgut Ozal Medical Center between October 2006 and January 2010 were evaluated in this retrospective study. A reverse-T incision was made for liver transplantation. The hernias were repaired with onlay polypropylene mesh. Age, gender, post-transplant relaparatomy, the type, the result of surgery for the incisional hernia, and risk factors for developing incisional hernia were evaluated.

Results

An incisional hernia developed in 44 of 173 (25.4 %) patients after LDLT. Incisional hernia repair was performed in 14 of 173 patients (8.1 %) who underwent LDLT from October 2006 to January 2010. Relaparatomy was associated with incisional hernia (p = 0.0002). The mean age at the time of the incisional hernia repair was 51 years, and 79 % of the patients were men. The median follow-up period was 19.2 (13–36) months after the hernia repair. Three patients with intestinal incarceration underwent emergency surgery to repair the hernia. Partial small bowel resection was required in one patient. Postoperative complications included seroma formation in one patient and wound infection in another. There was no recurrence of hernia during the follow-up period.

Conclusions

The incidence of incisional hernia after LDLT was 25.4 % in this study. Relaparatomy increases the probability of developing incisional hernia in recipients of LDLT. According to the results of the study, repair of an incisional hernia with onlay mesh is a suitable option.  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