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   7125篇
  免费   335篇
  国内免费   76篇
耳鼻咽喉   28篇
儿科学   141篇
妇产科学   133篇
基础医学   1073篇
口腔科学   147篇
临床医学   426篇
内科学   1747篇
皮肤病学   252篇
神经病学   600篇
特种医学   252篇
外科学   1073篇
综合类   23篇
预防医学   179篇
眼科学   73篇
药学   515篇
中国医学   18篇
肿瘤学   856篇
  2023年   29篇
  2022年   93篇
  2021年   148篇
  2020年   76篇
  2019年   102篇
  2018年   149篇
  2017年   158篇
  2016年   170篇
  2015年   170篇
  2014年   242篇
  2013年   279篇
  2012年   468篇
  2011年   518篇
  2010年   305篇
  2009年   243篇
  2008年   425篇
  2007年   501篇
  2006年   490篇
  2005年   488篇
  2004年   479篇
  2003年   501篇
  2002年   473篇
  2001年   70篇
  2000年   54篇
  1999年   87篇
  1998年   123篇
  1997年   81篇
  1996年   69篇
  1995年   73篇
  1994年   65篇
  1993年   53篇
  1992年   42篇
  1991年   39篇
  1990年   38篇
  1989年   41篇
  1988年   20篇
  1987年   23篇
  1986年   10篇
  1985年   14篇
  1984年   13篇
  1983年   7篇
  1982年   20篇
  1981年   9篇
  1980年   12篇
  1979年   13篇
  1978年   8篇
  1977年   7篇
  1976年   6篇
  1973年   7篇
  1969年   5篇
排序方式: 共有7536条查询结果,搜索用时 15 毫秒
81.

Background

Large superficial neoplasias of the ileocecal region pose an increased degree of complexity for endoscopic resection. This study aimed to evaluate the safety and efficacy of endoscopic submucosal dissection (ESD) for large superficial colorectal neoplasias including ileocecal lesions.

Methods

A total of 33 superficial colorectal neoplasias, including eight neoplasias in the ileocecal region, were treated with ESD from December 2005 to April 2009. Therapeutic efficacy, complications, and follow-up results were retrospectively evaluated among three groups: ileocecal region, colon, and rectum.

Results

The mean size of all resected neoplasias was 35 ± 15 mm (range, 20–80 mm) and that of all resected specimens was 41 ± 15 mm (range, 23–82 mm). The mean procedural time was 121 ± 90 min (range, 22–420 min). The difference in mean values among the three groups was not significant. The overall rate of en bloc resection was 91% (30/33). Histopathologically, both the lateral and vertical margins in the specimens resected en bloc tested negative (30/30). The rate for en bloc resection in the ileocecal region did not differ significantly from that for the other two groups (p = 0.20 compared with the rate for the colon and p = 0.12 compared with the rate for the rectum). Complications such as perforation and postoperative bleeding did not occur in the ileocecal group. No recurrence was observed in any cases during the mean follow-up period of 20 ± 12 months (range, 4–44 months).

Conclusions

The ESD approach is safe and effective for treating large superficial neoplasias of the ileocecal region such as other colorectal neoplasias.  相似文献   
82.

Background

Safety and efficacy of endoscopic submucosal dissection (ESD) for esophageal neoplasias have not been adequately investigated in elderly patients. This study was designed to evaluate the safety and efficacy of ESD for esophageal neoplasias in elderly patients.

Methods

Fifty-three superficial esophageal neoplasias treated with ESD using a combination of small-caliber-tip transparent hood and flex knife from May 2006 to June 2009 were divided into elderly group (aged 70 years or older: 25 lesions in 23 patients) and nonelderly group (younger than aged 70 years: 28 lesions in 25 patients). Therapeutic efficacy, complications, and follow-up results were evaluated retrospectively.

Results

The history of cerebral infarction or cardiopulmonary disease and the usage of antiplatelet agents or anticoagulants were significantly higher in elderly group (p 0.0050 and p 0.0013, respectively). Median procedural times in the elderly group and the nonelderly group were 93 ± 53 (range, 42–235) min and 95 ± 55 (range, 40–230) min (p 0.73), respectively. Median sizes of the neoplasias and the resected specimens were 14 ± 11 (range, 5–45) mm and 15 ± 17 (range, 5–83) mm (p 0.56), and 35 ± 12 (range, 18–60) mm and 38 ± 17 (range, 18–90) mm (p 0.38), respectively. En bloc resection rate was 100% in each group. Body temperature and white blood cell counts of the next day after ESD were significantly higher in the nonelderly group than in the elderly group (p 0.0087 and p 0.0043, respectively). There were no complications, such as postoperative bleeding or perforation, in each group. The median follow-up period of 23 ± 10 (range, 4–35) months in the elderly group revealed no local or distant metastasis.

Conclusions

ESD with a combination of small-caliber-tip transparent hood and flex knife is a safe and effective treatment for superficial esophageal neoplasia in elderly and nonelderly patients.  相似文献   
83.
BACKGROUND: Propofol and droperidol decrease the incidence of postoperative nausea and vomiting (PONV). We investigated the incidence of PONV after total intravenous anesthesia (TIVA) with propofol alone versus combined use of droperidol and propofol. METHODS: Eighty three patients, who had undergone laparoscopic gynecologic surgery with TIVA using propofol and fentanyl, were retrospectively evaluated whether droperidol had affected the incidence of early (up to six hours postoperatively) and late (6-24 hours postoperatively) PONV. Group D (46 patients) received droperidol intravenously at the end of surgery. Group N (37 patients) received no droperidol. RESULTS: The incidences of early nausea were 27% in Group N and 4% in Group D (P<0.01). The incidences of early vomiting were 0% in Group N and 8% in Group D. The incidences of late nausea were 14% in Group N and 13% in Group D. The incidences of late vomiting were 3% in Group N and 7% in Group D. CONCLUSIONS: Droperidol was useful in reducing the incidence of early nausea and vomiting after total intravenous anesthesia with propofol and fentanyl in the patients undergoing laparoscopic surgery.  相似文献   
84.
The purpose of this study was to ascertain the usefulness of preoperative evaluations of donors by computed tomography (CT) volumetry and CT cholangiography for prevention of unexpected liver failure and biliary complications after donor right hepatectomy for adult-to-adult living donor liver transplantation. Fifty-two donors who underwent right hepatectomy without the middle hepatic vein were enrolled in this study. The values of graft weight (GW) were significantly correlated with those of estimated graft volume (GV; P < 0.0001). GW was predicted by the following formula: GW = 155.25 + 0.658 x GV; r(2) = 0.489. CT cholangiography revealed anatomical variants of biliary structure in one-third of the donors and also clearly showed one or two small biliary branches from the caudate lobe to the right hepatic ducts or the confluence in 58% of the donors. Biliary leakage, which was treated by conservative therapy, occurred in only one donor (1.9%). No donors received homologous blood transfusion. Hyperbilirubinemia (serum total bilirubin >5 mg/dl) occurred in 5.8% of the donors during their early postoperative periods. Precise evaluations of liver remnant volume by CT volumetry and biliary variation by CT cholangiography are essential for performing safe donor hepatectomy, preventing hepatic insufficiency and minimizing the risk of biliary tract complications.  相似文献   
85.
We report a case of retroperitoneal tumor which turned out to be liposarcoma by the histological evaluation of its recurrent tumor, although the initial tumor was diagnosed as malignant fibrous histiocytoma (MFH). A retroperitoneal tumor in a 62-year-old man was removed and pathologically diagnosed as MFH. Five years after the initial surgery, computed tomography (CT) demonstrated a recurrent tumor near the spleen. The tumor was resected together with the spleen, tail of pancreas, and connective tissue due to adhesion and diagnosed as well-differentiated liposarcoma with sclerosing component. Generally dedifferentiated liposarcoma is difficult to distinguish from MFH and the presence of a well-differentiated liposarcoma component in the adjacent adipose tissue leads to the diagnosis of dedifferentiated liposarcoma. The clinical course of the present case indicated that the initial tumor was dedifferentiated liposarcoma and the recurrent tumor developed from the surrounding well-differentiated liposarcoma.  相似文献   
86.
BACKGROUND: The techniques of right hepatic trisectionectomy are now standardized in patients with hepatocellular or metastatic carcinoma, but not in those with hilar cholangiocarcinoma. METHODS: Under preoperative diagnosis of hilar cholangiocarcinoma, 8 patients underwent "anatomic" right hepatic trisectionectomy with en bloc resection of the caudate lobe and the extrahepatic bile duct, in which the bile ducts of the left lateral section were divided at the left side of the umbilical fissure following complete dissection of the umbilical plate. RESULTS: Liver resection was successfully performed, and all patients were discharged from the hospital in good condition, giving a mortality of 0%. All patients were histologically diagnosed as having cholangiocarcinoma. The proximal resection margins were cancer-negative in 7 patients and cancer-positive in 1 patient. Four patients with multiple lymph node metastases died of cancer recurrence within 3 years after hepatectomy. One patient died of liver failure without recurrence 42 months after hepatectomy. The remaining 3 patients without lymph node metastasis are now alive after more than 5 years. CONCLUSIONS: Anatomic right hepatic trisectionectomy with caudate lobectomy can produce a longer proximal resection margin and can offer a better chance of long-term survival in some selected patients with advanced hilar cholangiocarcinoma.  相似文献   
87.
88.
Background and Aim:  There have so far been few reports describing echographic studies of chemically-induced carcinogenesis in rodent livers. Using echography, we observed diethylnitrosamine-induced liver tumors in rats and examined the effect of an intratumoral injection of an inhibitor of c-Jun N-terminal kinase.
Methods:  Male Wistar rats were given 100 ppm of diethylnitrosamine for 6 weeks and their liver nodules were examined by echography weekly. The size of the nodules was measured and they were examined histologically. The effect of SP600125, an inhibitor of c-Jun N-terminal kinase, on the growth of rat hepatoma cell line McA-RH7777 was tested in vitro . Thereafter, SP600125 was injected into the liver nodules under echographic guidance in vivo and the changes in the proliferating cell nuclear antigen expression and size of the nodules were examined.
Results:  The four distinct lobes of rat livers were clearly observed by transabdominal echography. The nodules in the livers were first detected 6 weeks after the treatment began, when they were as small as 1.6 mm in diameter. The nodules thereafter became more malignant histologically as they grew larger than 4 mm. SP600125 decreased the expression of proliferating cell nuclear antigen and the growth of McA-RH7777 cells. After SP600125 was injected in vivo , the proliferating cell nuclear antigen level and the growth rate of the rat liver nodules all significantly decreased.
Conclusions:  Our results indicate that echography is quite useful for follow-up studies of liver carcinogenesis in rats, and c-Jun N-terminal kinase might be another therapeutic target in liver neoplasms.  相似文献   
89.
90.
We report a near-fatal case of cerebral edema associated with adenovirus type 2 infection in a previously healthy 19-month-old boy. After 3 to 4 d of high fever and a series of seizures, he developed persistent loss of consciousness and irreversible respiratory arrest. Adenovirus type 2 infection was diagnosed by virus isolation from his stool and serology.  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