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   1745篇
  免费   97篇
  国内免费   25篇
儿科学   24篇
妇产科学   5篇
基础医学   194篇
口腔科学   9篇
临床医学   113篇
内科学   613篇
皮肤病学   16篇
神经病学   108篇
特种医学   45篇
外科学   372篇
综合类   4篇
预防医学   75篇
眼科学   11篇
药学   84篇
中国医学   2篇
肿瘤学   192篇
  2023年   9篇
  2022年   24篇
  2021年   57篇
  2020年   25篇
  2019年   19篇
  2018年   38篇
  2017年   28篇
  2016年   43篇
  2015年   47篇
  2014年   56篇
  2013年   80篇
  2012年   160篇
  2011年   154篇
  2010年   63篇
  2009年   53篇
  2008年   100篇
  2007年   100篇
  2006年   89篇
  2005年   80篇
  2004年   90篇
  2003年   87篇
  2002年   91篇
  2001年   26篇
  2000年   17篇
  1999年   28篇
  1998年   24篇
  1997年   17篇
  1996年   16篇
  1995年   11篇
  1994年   16篇
  1993年   29篇
  1992年   15篇
  1991年   19篇
  1990年   14篇
  1989年   15篇
  1988年   11篇
  1987年   9篇
  1986年   8篇
  1985年   10篇
  1984年   9篇
  1982年   5篇
  1979年   6篇
  1977年   5篇
  1975年   5篇
  1974年   7篇
  1973年   6篇
  1971年   7篇
  1968年   4篇
  1967年   5篇
  1966年   4篇
排序方式: 共有1867条查询结果,搜索用时 421 毫秒
991.
992.
Middle pancreatectomy is parenchyma- and adjacent organ-sparing pancreatectomy indicated for small tumors located in the body, but deeply located in the gland, and therefore hard to enucleate. Others lesions including pancreatic trauma or arteriovenous malformation are also candidate targets. Invasive ductal carcinoma, even when the tumor is small enough, is not eligible because the most of these tumors show extrapancreatic invasion. After exposure of neck to body of the pancreas, middle pancreatectomy was performed by proximal and distal transection, reconstruction after Roux-Y pancreaticojejunostomy, which is the most common. This procedure is low-invasive and allow the preservation of exocrine and endocrine pancreatic function without loss of duodenal passage, however, it also has a high morbidity associated with pancreatic fistula. This article provides indications and surgical techniques with special focus on the procedure of middle pancreatectomy.  相似文献   
993.
A 39-y-old man, who had an episode of pancreatic bleeding due to chronic pancreatitis, received total pancreatectomy with islet autotransplantation (TP with IAT). Intraoperative ultrasound (US) examination was done to detect transplanted islets and evaluate the quality of US imaging. Islet isolation from the resected total pancreas was performed and approximately 230,000 islet equivalents (IEQ) (the tissue volume was 600 µL and the purity was 30%) were acquired. A double lumen catheter, used for transplantation and for monitoring the portal vein pressure, was inserted into the portal vein via the superior mesenteric vein, and the tip of the catheter was positioned at the bifurcation of the anterior and posterior branch of the portal vein to selectively infuse the islets into the right lobe of the liver in order to prevent total liver embolization. Intraoperative US examination (central frequency 7.5 MHz, Nemio™ XG, Toshiba Medical System Co.) was started at the same time as the transplantation. US examination revealed the transplanted islets as hyperechoic clusters that flowed from the tip of the catheter to the periphery of the portal vein. There were no findings of portal thrombosis or bleeding in the US image, and also no increase of the portal vein pressure during transplantation. In conclusion, we succeeded in visualizing human islets using US, which enabled us to perform islet transplantation safely. The hyperechoic images were considered to be viable islets. Intraoperative US examination can be useful for detecting islets at transplantation in a clinical setting.  相似文献   
994.
The present study was conducted to evaluate the efficacy and safety of BLM-240 (desflurane) in comparison to sevoflurane in Japanese patients. A total of 216 patients were enrolled in this randomized comparative study at 15 medical institutions. The patients received either BLM-240 with 50–70 % N2O in O2 (n = 111), BLM-240 with 30 % O2 in air (n = 55), or sevoflurane with 50–70 % N2O in O2 (n = 50). Efficacy was evaluated by an efficacy rate based on an efficacy evaluation criteria and recovery time to extubation from the discontinuation of the anesthetics. Safety was evaluated by incidence of adverse drug reactions (ADR) and other clinical indicators. The efficacy rate of BLM-240 was 98.8 % (164/166 patients), indicating that BLM-240 is effective as an anesthetic. Time from discontinuation of anesthetic delivery to extubation was 9.7 ± 0.6 min in the BLM-240/N2O group and 14.3 ± 0.9 min in the sevoflurane/N2O group, meeting the pre-defined non-inferiority criteria of BLM-240 to sevoflurane. There was no statistically significant difference in the incidence of total ADR between the BLM-240 group (62.0 %) and sevoflurane group (48.0 %). The results indicate that BLM-240 is an effective and safe inhalation anesthetic in Japanese patients.  相似文献   
995.
The purpose of our study was to measure the reduction rate of radiation dose and variability of image noise using the angular beam modulation (ABM) on computed tomography (CT) fluoroscopy. The Alderson-Rando phantom and the homemade phantom were used in our study. These phantoms were scanned at on-center and off-center positions at -12 cm along y-axis with and without ABM technique. Regarding the technique, the x-ray tube is turned off in a 100-degree angle sector at the center of 12 o'clock, 10 o'clock, and 2 o'clock positions during CT fluoroscopy. CT fluoroscopic images were obtained with tube voltages, 120 kV; tube current-time product per reconstructed image, 30 mAs; rotation time, 0.5 s/rot; slice thickness, 4.8 mm; and reconstruction kernel B30s in each scanning. After CT scanning, radiation exposure and image noise were measured and the image artifacts were evaluated with and without the technique. The reduction rate for radiation exposure was 75-80% with and without the technique at on-center position regardless of each angle position. In the case of the off-center position at -12 cm, the reduction rate was 50% with and without the technique. In contrast, image noise remained constant with and without the technique. Visual inspection for image artifacts almost have the same scores with and without the technique and no statistical significance was found in both techniques (p>0.05). ABM is an appropriate tool for reducing radiation exposure and maintaining image-noise and artifacts during CT fluoroscopy.  相似文献   
996.
Intraductal papillary neoplasm of the bile duct (IPNB) is a grossly visible papillary biliary neoplasm with morphological variations and occasional invasion. Recently a new classification of IPNB into type 1 and type 2 was proposed in which the type 1 IPNBs consist of fine papillary neoplastic glands and the type 2 IPNBs consist of complex branching glands, seldom with foci of solid-tubular components. However, clinicopathological and molecular characteristics of these types of IPNBs are yet to be identified. We aimed to uncover clinicopathological and molecular characteristics of the types of IPNBs. Thirty-six IPNBs were studied retrospectively. Clinicopathological features as well as molecular alterations of 31 genes were evaluated by means of targeted next-generation sequencing and immunohistochemical examination of expression of mucin and cancer-associated molecules. The 36 IPNBs were classified into 22 of type 1 and 14 of type 2. The type 1 IPNBs were associated with a non-invasive phenotype, intestinal and oncocytic subtypes, development in the intrahepatic bile duct, overt mucin production, and a relatively good prognosis. The type 2 IPNBs were associated with an invasive phenotype, the pancreatobiliary subtype, development within the extrahepatic bile duct, and worse prognosis compared with the type 1 IPNBs. In the molecular analysis, recurrent mutations were found in TP53 (34.3%), KRAS (31.4%), STK11 (25.7%), CTNNB1 (17.1%), APC (14.3%), SMAD4 (14.3%), GNAS (11.4%), PBRM1 (11.4%), ELF3 (8.6%), KMT2C (8.6%), NF1 (8.6%), PIK3CA (8.6%), ARID1A (5.7%), ARID2 (5.7%), BAP1 (5.7%), BRAF (5.7%), EPHA6 (5.7%), ERBB2 (5.7%), ERBB3 (5.7%), KMT2D (5.7%), and RNF43 (5.7%). Mutations in KRAS and GNAS were enriched in the type 1 IPNBs, whereas mutations in TP53, SMAD4, and KMT2C were enriched in the type 2 IPNBs. These results indicate that IPNBs consist of two distinct types of neoplasms specifically associated with clinicopathological features and molecular phenotypes. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.  相似文献   
997.

Background

Although femoral nerve block provides good analgesia after total knee arthroplasty (TKA), residual posterior knee pain may decrease patient satisfaction. We compared the efficacy of periarticular infiltration analgesia (PIA) and sciatic nerve block (SNB) for posterior knee pain.

Methods

Forty-nine patients scheduled for TKA were prospectively randomized into the PIA group (n = 25) or SNB group (n = 24) and received general anesthesia with ultrasound-guided femoral nerve block (FNB). In the PIA group, 60 ml 0.5 % ropivacaine and 0.3 mg epinephrine were injected intraoperatively into the periarticular soft tissue before inserting the components. In the SNB group, patients received ultrasound-guided SNB with 20 ml 0.375 % ropivacaine and periarticular infiltration with 20 ml normal saline and 0.3 mg epinephrine. We evaluated postoperative pain scores, posterior knee pain, frequency of rescue analgesics for 36 h, and performance time of PIA and SNB.

Results

Visual analogue pain scores at 12–24 h were significantly lower in the PIA group than in the SNB group (p < 0.05). The majority of patients had no posterior knee pain. There were no significant differences between the groups in frequency and time of first administration of rescue analgesics and in side effects. Time for performance of periarticular infiltration was significantly shorter than that for SNB (p < 0.05). The dose of intraoperative remifentanil was significantly lower in the SNB group than in the PIA group (p < 0.001).

Conclusions

The combination of FNB and PIA provides sufficient analgesia after TKA. The rapid and convenient periarticular infiltration technique could be a good alternative to SNB.  相似文献   
998.

Background and purpose

Thromboprophylaxis is recommended for preventing postoperative venous thromboembolism (VTE) after abdominal surgery; however, its use after major hepatobiliary–pancreatic surgery is typically avoided as it increases the risk of bleeding. We conducted this study to evaluate the safety of thromboprophylaxis after major hepatobiliary–pancreatic surgery.

Methods

We analyzed the rates of postoperative bleeding, VTE, morbidity, and prolonged hospital stay in 349 patients who underwent major hepatobiliary–pancreatic surgery, such as pancreaticoduodenectomy, hemihepatectomy or greater, and hepatopancreaticoduodenectomy.

Results

Chemical thromboprophylaxis was associated with significantly increased rates and risks of overall bleeding events vs. no chemical thromboprophylaxis (26.6 vs. 8.5 %, respectively). The rate of minor hemorrhage was significantly higher in patients who received chemical thromboprophylaxis (21.7 vs. 3.5 %); however, there were no differences in the rate of major hemorrhage requiring blood transfusion or hemostatic intervention between the groups (4.8 vs. 4.9 %). The postoperative VTE rate was also significantly decreased by chemical thromboprophylaxis (2.9 vs. 7.7 %). However, chemical thromboprophylaxis did not affect the rate of SSI, severe morbidity, or duration of the postoperative hospital stay.

Conclusion

We consider that chemical thromboprophylaxis is beneficial and can be safely used even after major hepatobiliary–pancreatic surgery.  相似文献   
999.

Purpose

We, herein, examined the role of the intraluminal contents and continuity of colonic intrinsic neurons in intracolonic capsaicin-induced enhancement of colonic motility and defecation.

Methods

Five beagle dogs were equipped with three strain gauge force transducers throughout the colon. The colonic contractile activity in response to intracolonic capsaicin was studied in intact dogs, dogs after colonic cleansing and dogs with transection/re-anastomosis (T/R) between the proximal and middle colon. The effects of intravenous yohimbine, a α2 adrenergic antagonist, on the colonic motility and defecation were also studied in the same models.

Results

In intact dogs, capsaicin (10 mg) and yohimbine (2 mg/kg) immediately induced contractions throughout the colon, with defecation occurring in all experiments. In dogs after colonic cleansing and T/R, the capsaicin (10 mg)-induced enhancement of colonic motility was decreased in the middle and distal colon, and capsaicin-induced defecation was observed in 0–20 % of experiments (p < 0.05 compared to intact dogs). The effect of yohimbine (2 mg/kg) in inducing colonic contractions was unaltered after colonic cleansing and T/R; in contrast, yohimbine-induced defecation was not observed after colonic cleansing, but was unchanged after T/R.

Conclusions

The continuity of the colonic intrinsic nerves as well as the intraluminal contents appear to play an important role in the colonic motor response to intracolonic capsaicin.  相似文献   
1000.

Purpose

To evaluate the foregut and hindgut hypotheses for metabolic surgery in obese rats with diabetes.

Methods

Otsuka Long-Evans Tokushima fatty rats were divided into a sham operation group, a partial duodeno-jejunal bypass (P-DJB) group, and a complete DJB (C-DJB) group. P-DJB is a model to test foregut hypothesis, whereas C-DJB is a model to test both hypotheses. We performed oral glucose tolerance tests (OGTT) on all groups at baseline, and then 4 and 8 weeks postoperatively. The rats were killed thereafter and the plasma levels of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) were measured. A separate sub-group of C-DJB rats underwent OGTT after treatment with the GLP-1 antagonist, the PYY antagonist, or saline.

Results

Marked improvement of the blood glucose control during the OGTT was noted 8 weeks after C-DJB, but not 8 weeks after P-DJB or the sham operation. The serum GLP-1 and PYY levels were higher in the C-DJB group than in the other two groups. Pretreatment with the GLP-1 antagonist increased the blood glucose levels 30 min after the OGTT in the C-DJB rats.

Conclusions

Improvement in glucose metabolism after DJB was associated with the inflow of bile and pancreatic juice into the ileum, supporting validity of the hindgut hypothesis. GLP-1 appears to play a role in this improvement.  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