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   864篇
  免费   33篇
  国内免费   4篇
耳鼻咽喉   43篇
儿科学   26篇
妇产科学   22篇
基础医学   75篇
口腔科学   6篇
临床医学   94篇
内科学   175篇
皮肤病学   30篇
神经病学   43篇
特种医学   68篇
外科学   163篇
综合类   20篇
预防医学   32篇
眼科学   11篇
药学   40篇
中国医学   1篇
肿瘤学   52篇
  2023年   8篇
  2022年   14篇
  2021年   18篇
  2020年   14篇
  2019年   24篇
  2018年   22篇
  2017年   19篇
  2016年   26篇
  2015年   36篇
  2014年   54篇
  2013年   57篇
  2012年   52篇
  2011年   49篇
  2010年   29篇
  2009年   35篇
  2008年   58篇
  2007年   54篇
  2006年   52篇
  2005年   61篇
  2004年   51篇
  2003年   33篇
  2002年   20篇
  2001年   12篇
  2000年   11篇
  1999年   8篇
  1998年   9篇
  1997年   4篇
  1996年   4篇
  1995年   7篇
  1994年   2篇
  1993年   3篇
  1992年   5篇
  1991年   3篇
  1990年   7篇
  1989年   6篇
  1988年   2篇
  1986年   2篇
  1985年   3篇
  1984年   3篇
  1983年   3篇
  1982年   2篇
  1978年   1篇
  1977年   1篇
  1976年   2篇
  1973年   2篇
  1972年   2篇
  1971年   2篇
  1970年   4篇
  1969年   2篇
  1965年   1篇
排序方式: 共有901条查询结果,搜索用时 0 毫秒
11.
Tekin G  Sivri N  Tekin YK  Topal E  Erbay AR  Yetkin E 《Angiology》2012,63(7):552-555
We assessed the clinical echocardiograhic, hematological, and biochemical parameters in patients with dilated cardiomyopathy (DCMP) and control individuals mainly focusing on the mean platelet volume (MPV) in terms of DCMP and left ventricle (LV) thrombus formation. Consecutive patients (n = 251) with DCMP and 266 patients without DCMP were studied. Mean platelet volume was significantly greater in patients with DCMP than in control patients (P < .05 for all comparisons). Comparing DCMP patients with LV thrombus (19 patients, 8%) and without LV thrombus (232 patients, 92%) showed that the prevalence of smokers was significantly higher and ejection fraction was significantly lower in patients with LV thrombus. We have shown that patients with DCMP have significantly higher MPV suggesting more platelet activation and the MPV of patients with DCMP and LV thrombus is comparable to those of patients without LV thrombus.  相似文献   
12.
Cholangiocellular carcinoma (CC) originates from topographically heterogeneous cholangiocytes. The cylindrical mucin-producing cholangiocytes are located in large bile ducts and the cuboidal non-mucin-producing cholangiocytes are located in ductules containing bipotential hepatic progenitor cells (HPCs). We investigated the clinicopathological and molecular features of 85 resected CCs (14 hilar CCs [so-called Klatskin tumor], 71 intrahepatic CCs [ICCs] including 20 cholangiolocellular carcinomas [CLCs], which are thought to originate from HPCs]) and compared these with the different cholangiocyte phenotypes, including HPCs. Immunohistochemistry was performed with biliary/HPC and hepatocytic markers. Gene expression profiling was performed in different tumors and compared with nonneoplastic different cholangiocyte phenotypes obtained by laser microdissection. Invasion and cell proliferation assay were assessed using different types of CC cell lines: KMC-1, KMCH-1, and KMCH-2. Among 51 ICCs, 31 (60.8%) contained only mucin-producing CC features (muc-ICCs), whereas 39.2% displayed histological diversity: focal hepatocytic differentiation and ductular areas (mixed-ICCs). Clinicopathologically, muc-ICCs and hilar CCs showed a predominantly (peri-)hilar location, smaller tumor size, and more lymphatic and perineural invasion compared with mixed-ICCs and CLCs (predominantly peripheral location, larger tumor size, and less lymphatic and perineural invasion). Immunoreactivity was similar in muc-ICCs and hilar CCs and in mixed-ICCs and CLCs. S100P and MUC1 were significantly up-regulated in hilar CCs and muc-ICCs compared with mixed-ICCs and CLCs, whereas NCAM1 and ALB tended to be up-regulated in mixed-ICCs and CLCs compared with other tumors. KMC-1 showed significantly higher invasiveness than KMCH-1 and KMCH-2. Conclusion: Muc-ICCs had a clinicopathological, immunohistochemical, and molecular profile similar to that of hilar CCs (from mucin-producing cholangiocytes), whereas mixed-ICCs had a profile similar to that of CLCs (thought to be of HPC origin), possibly reflecting their respective cells of origin.  相似文献   
13.
14.
We investigated the ultrastructural effects of the organophosphate compound methamidophos and treatment with atropine and pralidoxime (2-PAM) on rat kidneys. Male Wistar albino rats were assigned to four groups. Group 1 received 30 mg/kg methamidophos, the LD50 for this compound in rats, via oral gavage. Group 2 received only physiologic saline. Group 3 rats received 30 mg/kg methamidophos and were treated with 2-PAM and atropine via intraperitoneal injection when cholinergic symptoms were noted. Group 4 served as a control, and received physiologic saline in equivalent volumes and routes to Group 3. Kidney tissues were prepared for electron microscopic studies. No ultrastructural changes were detected in Group 1 after acute poisoning with methamidophos and in Group 3 treated with antidotes after poisoning. Acute organophosphate poisoning and antidotal treatment in this model are not associated with histopathological changes in the rat kidney but the models with different organophosphate compounds, by administrating the different dosages, may be more illuminative in explaining the effects of these chemicals in kidney.  相似文献   
15.

Background

Endoscopic ampullectomy is established as a valuable treatment for adenomas of the Vaterian papilla. Few large series are available, however, let alone any with long-term follow-up. Moreover, multiple tangible issues remain. The aim of our study was to evaluate efficacy, safety, and outcome of endoscopic ampullectomy and compare it to existing literature

Methods

This is a single-center, retrospective study with a minimal follow-up of 3 years including 91 patients, including familial adenomatous polyposis (FAP) and non-FAP, who had an endoscopic ampullectomy between 2000 and 2008. Outcome parameters included ampulloma characteristics, biotical accuracy as well as safety, efficacy, recurrence rate, and survival after endoscopic ampullectomy.

Results

Endoscopic resection was successful in 71 patients (78 %). Histological review of the resected specimens revealed nonspecific changes (13.8 %), low or medium grade dysplasia (52.9 %), high grade dysplasia (21.8 %) and carcinoma (18.3 %). Bioptic accuracy was 38.3 %. Overall complications were observed in 23 patients (25.2 %): pancreatitis (15.4 %), hemorrhage (12.1 %) and cholangitis (4.9 %). Recurrence occurred in 18.3 %. Fourteen patients underwent pancreaticoduodenectomy. Survival after complete endoscopic ampullectomy was excellent for patients with low to moderate grade dysplasia and high grade dysplasia. Incomplete endoscopic resection of high grade dysplasia or invasive carcinoma was associated with unfavorable outcome when treated merely endoscopically.

Conclusions

Endoscopic ampullectomy is obligatory for assessment of the true histological nature of an ampulloma. Endoscopic resection is a safe and efficient procedure for adenomas with low to moderate dysplasia but also for high grade dysplastic lesions, provided that a complete endoscopic resection is achieved.  相似文献   
16.
Purpose: To determine whether prophylaxis with etanercept, an anti-inflammatory drug, would decrease the severity of lung injury in a neonatal rat model of bronchopulmonary dysplasia (BPD); Materials and Methods: Rat pups were divided into three groups: pups exposed to room air (group 1; n = 10), to hyperoxia + placebo (group 2; n = 9), and to hyperoxia + etanercept (group 3; n = 8). Lung morphology was assessed by alveolar surface area percentage, which is a measure of alveolar size. The severities of lung inflammation and antioxidant capacity were assessed by quantifying tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), malondialdehyde (MDA), and superoxide dismutase (SOD) from lung homogenate; Results: The percentage of alveolar surface areas were significantly higher in group 3 compared to group 2 (p = .004) and similar in both group 1 and group 3 (p = .21). The mean level of lung MDA was significantly higher in group 2 compared to group 1 and group 3 (p < .05 for both). Lung homogenate SOD activities in group 3 was significantly higher than group 2 (p < .001). Furthermore, group 3 pups had lower levels of TNF-α and TGF-β in lung homogenate than that in group 2 (p < .05 for both) but similar in both group 1 and group 3; Conclusion: Etanercept has favorable effects on alveolarization as well as inflammation and oxidative stress markers in a neonatal rat model of BPD.  相似文献   
17.
18.
19.
20.

Background

The worldwide introduction of multimodal enhanced recovery programs has also changed perioperative care in patients who undergo liver resection. This study was performed to assess current perioperative practice in liver surgery in 11 European HPB centers and compare it to enhanced recovery after surgery (ERAS) principles.

Methods

In each unit, 15 consecutive patients (N = 165) who underwent hepatectomy between 2010 and 2012 were retrospectively analyzed. Compliance was classified as “full,” “partial,” or “poor” whenever ≥80, ≥50, or <50 % of the 22 ERAS protocol core items were met. The primary study end point was overall compliance with the ERAS core program per unit and per perioperative phase.

Results

Most patients were operated on for malignancy (91 %) and 56 % were minor hepatectomies. The median number of implemented ERAS core items was 9 (range = 7–12) across all centers. Compliance was partial in the preoperative (median 2 of 3 items, range = 1–3) and perioperative phases (median 5 of 10 items, range: 4–7). Median postoperative compliance was poor (median 2 of 9 items, range = 0–4). A statistically significant difference was observed between median length of stay and median time to recovery (7 vs. 5 days, P < 0.001).

Conclusion

Perioperative care among centers that perform liver resections varied substantially. In current HPB surgical practice, some elements of the ERAS program, e.g., preoperative counselling and minimal fasting, have already been implemented. Elements in the perioperative phase (avoidance of drains and nasogastric tube) and postoperative phase (early resumption of oral intake, early mobilization, and use of recovery criteria) should be further optimized.  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