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   3269篇
  免费   119篇
  国内免费   8篇
耳鼻咽喉   12篇
儿科学   35篇
妇产科学   27篇
基础医学   617篇
口腔科学   35篇
临床医学   190篇
内科学   702篇
皮肤病学   30篇
神经病学   181篇
特种医学   119篇
外科学   710篇
综合类   10篇
预防医学   119篇
眼科学   42篇
药学   181篇
中国医学   4篇
肿瘤学   382篇
  2023年   14篇
  2022年   29篇
  2021年   60篇
  2020年   33篇
  2019年   38篇
  2018年   41篇
  2017年   34篇
  2016年   63篇
  2015年   45篇
  2014年   64篇
  2013年   75篇
  2012年   120篇
  2011年   117篇
  2010年   88篇
  2009年   66篇
  2008年   141篇
  2007年   149篇
  2006年   182篇
  2005年   152篇
  2004年   178篇
  2003年   122篇
  2002年   152篇
  2001年   130篇
  2000年   147篇
  1999年   106篇
  1998年   55篇
  1997年   36篇
  1996年   46篇
  1995年   39篇
  1994年   35篇
  1993年   20篇
  1992年   89篇
  1991年   79篇
  1990年   68篇
  1989年   80篇
  1988年   68篇
  1987年   71篇
  1986年   43篇
  1985年   50篇
  1984年   37篇
  1983年   26篇
  1982年   19篇
  1981年   12篇
  1980年   14篇
  1979年   38篇
  1978年   14篇
  1977年   16篇
  1975年   11篇
  1974年   14篇
  1970年   15篇
排序方式: 共有3396条查询结果,搜索用时 15 毫秒
1.
PURPOSEWe aimed to evaluate mid- to long-term results of endovascular treatment for portal vein thrombosis (PVT) after living-donor liver transplantation (LDLT).METHODSThirty cases (14 males, 16 females; age range, 0.67–65 years) who underwent endovascular treatment including thrombolysis, angioplasty, stent placement, and/or collateral embolization for PVT after LDLT from 2001 to 2017 were retrospectively reviewed. Clinical and procedural data were collected and analyzed regarding the patency of the PVT site at the last follow-up date (PVT-free persistency) using Log-rank test. Results were considered statistically significant at p < 0.05.RESULTSMedian follow-up was 120 months. The technical success rate was 80% (n=24). Patency rates at 1 week and 1, 3, 6, 12, 36, and 60 months were 73%, 59%, 55%, 51%, 51%, 51%, and 51% for primary patency and 80%, 70%, 66%, 66%, 66%, 61%, and 61% for assisted patency after secondary endovascular treatment. PVT-free persistency rates regarding the subgroups were as follows: children under 12 years vs. adults, 50% vs. 68% (p = 0.42); acute vs. nonacute, 76% vs. 46% (p = 0.10); localized vs. extensive, 90% vs. 50% (p = 0.035); transileocolic approach vs. percutaneous-transhepatic approach, 71% vs. 54% (p = 0.39); and thrombolysis-based treatment vs. non-thrombolysis-based treatment, 71% vs. 44% (p = 0.12), respectively. Among technically successful cases, PVT-free persistency rate was 94% for those with hepatopetal flow in the peripheral portal vein vs. 17% for those without hepatopetal flow (p < 0.001). The only major complication occurring was pleural hemorrhage (n=1). Minor complications (i.e., fever) occurred in 18 patients (60%).CONCLUSIONIn conclusion, mid- to long-term portal patency following endovascular treatment was approximately 50%–60% in PVT patients after LDLT. PVT site patency over three months after the first endovascular treatment, localized PVT, and hepatopetal flow in the peripheral portal vein were identified as key prognostic factors for mid- to long-term portal patency.

Portal vein thrombosis (PVT) is a vascular complication of living-donor liver transplantation (LDLT), with an estimated incidence of up to 4% (1, 2). The risk of vascular complications, including PVT, is higher in LDLT compared with conventional deceased-donor liver transplantation, because of the smaller vessels, insufficient vessel length for reconstruction, neointimal proliferation, and higher risk of twisting and kinking of the vascular pedicle (3) due to smaller graft size than in deceased-donor liver transplantation. PVT after LDLT can lead to graft failure and the need for retransplantation or death (2), making immediate treatment crucial.Endovascular-based treatment is one option for treating PVT. The utility of target-focused thrombolysis, balloon angioplasty, and stent placement to restore portal flow has been reported previously (410). However, the efficacy of endovascular treatment after LDLT has only been presented in some case reports (11, 12) and the mid- to long-term outcomes remain unclear.The purpose of this study was to evaluate the technical success, feasibility, and mid- to long-term results of endovascular treatment for PVT after LDLT in our institution.  相似文献   
2.
To evaluate the main intake source of arsenic by the villagers from arsenic-affected families in Jalangi and Domkol blocks in Mushidabad district, West Bengal-India, we determined the concentrations of arsenic in tube-well water and in food composites, mainly including vegetables and cereals collected from the surveyed families which were cultivated in that region. The daily dietary intakes of arsenic by the villagers were estimated and the excretions of arsenic through urine and hair were determined. The arsenic concentrations in hair and urine of the studied population living in mild (2.78 microg/L), moderate (30.7 microg/L) and high (118 microg/L) arsenic-affected families were 133, 1,391 and 4,713 microg/kg and 43.1, 244 and 336 microg/L, respectively. The linear regressions show good correlations between arsenic concentrations in water vs hair (r(2)=0.928, p<0.001) and water vs urine (r(2)=0.464, p<0.01). Approximately 29.4%, 58.1% and 62.1% of adult population from mild, moderate and high arsenic-affected families were suffering from arsenical skin manifestations. The mean arsenic concentrations of food composites (vegetables and cereals) in high arsenic-affected families are not significantly different from mild arsenic-affected families. The daily dietary intakes of arsenic from water and food composites of the studied population, living in high, moderate and mild arsenic-affected families were 568, 228 and 137 microg, respectively. The linear regressions show good correlations between arsenic concentrations in hair vs daily dietary intake (r(2)=0.452, p<0.001) and urine vs daily dietary intake (r(2)=0.134, p<0.001). The water for drinking contributed 6.07%, 26.7% and 58.1% of total arsenic in our study from mild, moderate and high arsenic-affected families. The result suggested that the contaminated water from high arsenic-affected families should be the main source for intake of arsenic. On contrary, the contribution of arsenic-contaminated food composites from mild and moderate arsenic-affected families might be the main source for intake of arsenic. The Food and Agriculture Organization/World Health Organization (FAO/WHO) provisional tolerable weekly intake (PTWI) values of arsenic in our study were 3.32, 5.75 and 12.9 microg/kg body weight/day from mild, moderate and high arsenic-affected families, respectively, which is higher than the recommended PTWI value of arsenic (2.1 microg/kg body weight/day).  相似文献   
3.
4.
Objective The objective of the present study was to compare long-term results of single aortic valve replacement (AVR) with mechanical (St. Jude Medical valves: standard) and biologic (the Carpentier-Edwards pericardial) prostheses. Method: Between 1995 and 2002, 95 patients who underwent single AVR with mechanical (n=46) or biologic (n=49) prostheses were enrolled in this study. The mean age at the operation was 54.0±9.6 years (range: 20 to 69 years) with the mechanical and 68.8±7.1 years (range: 44 to 85 years) with the biologic prosthesis. Results: The 9-year actuarial survival rate, which was calculated by taking perioperative mortality into account, was 90.3±4.6% for patients with mechanical valves and 87.6 ±4.8% for patients with bioprostheses, with no difference between the two groups (p=0.342). The 9-year freedom rate from thromboembolism, reoperation, endocarditis was 94.8+3.6%, 100% and 97.8 ±2.2% for patients with mechanical valves and 98.0 ±2.0%, 97.5 ±3.4% and 95.0 ±3.4% for those with bioprostheses, respectively. After 9 years, freedom from cardiac death averaged 97.8% in the group with mechanical valves compared with 95.3% in those with bioprostheses (p=0.541). Conclusion: We conclude that the mid-term durability of the Carpentier-Edwards pericardial valve in the aortic position for the elderly is excellent. Nevertheless, the risk of tissue valve reoperation progressively increases with time, and a longer follow-up may be necessary to provide its value compared with the mechanical valves in a country like Japan with a high life expectancy. (Jpn J Thorac Cardiovasc Surg 2005; 53:465-469)  相似文献   
5.
Abstract: This study was investigated to clarify the role of intracellular Ca2+ following endotoxin treatment (1 mg/kg, intraperitoneally) to D-galactosamine-sensitized mice (400 mg/kg, intraperitoneally), and to observe lipid peroxide levels, an index of hepatotoxicity, in endotoxin/galactosamine (Ga1N)-challenged mice under activation of macrophages, especially Kupffer cells, by zymosan. The liver lipid peroxide level and serum glutamic pyruvic transminase activity in mice 18 hr after administration of endotoxin/Ga1N were markedly higher than those in mice treated only with endotoxin. In spite of an increase in lipid peroxide formation, there was little or no effect of Ga1N administration on xanthine oxidase and superoxide dismutase activities in mice given endotoxin. However, the injection of verapamil (10 mg/kg, subcutaneously) markedly decreased lipid peroxide levels in liver of endotoxin/Ga1N-injected mice. In the mice given a Ca2+-deficient diet, lipid peroxide level in liver after endotoxin/Ga1N injection was markedly decreased compared to that in mice fed a normal diet. Administration of dexamethasone (200 μg/kg, intraperitoneally) in mice 1 hr before treatment with endotoxin/Ga1N did not induce lipid peroxide formation. Administration of endotoxin to Ga1N-treated mice resulted in a higher level of liver cytosolic free Ca2+ ([Ca2+]i) than that in endotoxin-treated mice. On the other hand, Ca2+-ATPase activity in liver plasma membrane in the endotoxin/Ga1N-treated mice was markedly decreased as compared with endotoxin alone. On the contrary, the Ca2+-ATPase activity in liver mitochondria was higher in endotoxaemic mice treated with Ga1N than in mice given endotoxin alone. State 3 respiration and respiratory control index, which are parameters of mitochondrial function, were decreased more in the liver of mice treated with endotoxin/Ga1N than in the endotoxin-treated group. These findings suggest that [Ca2+]i may participate in the lipid peroxide formation which results from endotoxin/Ga1N-induced hepatotoxicity under conditions of zymosan-activated macrophages, and that the increases of endotoxin-sensitivity caused by Ga1N challenge may greatly contribute to Ca2+-mobilization in the hepatocyte.  相似文献   
6.
7.
A 52‐year‐old Japanese woman who presented with gastrointestinal (GI) bleeding underwent a proximal gastrectomy for a gastrointestinal stromal tumor (GIST) with a foveolar hyperplasia at the apex of the tumor, 4.5 cm in size, located in the upper body of the stomach. Although GIST are often asymptomatic and are found only incidentally, clinical symptoms such as bleeding, abdominal pain, or obstruction, occasionally lead to a premorbid diagnosis. When submucosal tumors present GI bleeding, the source of the bleeding usually is an ulceration of the mucosa over the tumor. However, in the present study, it was thought that the bleeding originated from the region of foveolar hyperplasia.  相似文献   
8.
Lymphocytic adenohypophysitis is considered to be an inflammatory disease of the adenohypophysis that is commonly present with visual disturbance and hypopituitarism. Its etiology remains unclear but it is often related to an autoimmune disorder involving other organs, such as the thyroid, parathyroid, or adrenal glands. We encountered a rare case of lymphocytic adenohypophysitis associated with sarcoidosis of the lung and eye during the follow-up period. A 23-year-old woman was hospitalized in July 1986, with a one-month history of headache and visual disturbances which began three days after her second normal delivery. On admission, she showed slight visual impairment and had a left temporal superior quadrantanopia. Endocrinological evaluation revealed thyroid and adrenal hypofunction, and low response of human growth hormone to the loading test. A skull X-ray showed normal shaped sella with some erosion of the dorsum. CT scan showed a rounded contrast-enhanced intrasellar mass extending into the suprasellar cistern. MRI (SR: 500/30) showed a homogeneous low intensity mass which contained a small high intensity area on the relative T2-weighted image (2000/50). A biopsy was performed via right frontotemporal craniotomy. The consistency of the resected tissue was firmer than that of pituitary adenoma. Histologically, the tissue showed diffuse lymphocytic infiltration with some normal adenohypophysis. Her postoperative course was uneventful and the visual impairment improved two months later after the operation. Six months after the operation, she was readmitted with complaints of general fatigue and breathlessness. Chest X-ray showed diffuse infiltration throughout both lung fields, but there was no bilateral hilar lymphadenopathy.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
9.
We report a 73-year-old woman with typical clinical, histological and immunofluorescence features of pemphigoid nodularis. Direct immunofluorescence studies of prurigo nodularis-like lesions and peribullous skin showed the linear deposition of IgG and C3 at the basement membrane zone. Circulating IgG against the basement membrane was also detected by indirect immunofluorescence. The serum from the patient was shown to contain the autoantibody against 230 kDa hemidesmosomal antigen associated with bullous pemphigoid antigen.  相似文献   
10.
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