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   1631篇
  免费   100篇
  国内免费   7篇
耳鼻咽喉   32篇
儿科学   51篇
妇产科学   17篇
基础医学   255篇
口腔科学   38篇
临床医学   85篇
内科学   439篇
皮肤病学   17篇
神经病学   76篇
特种医学   52篇
外科学   336篇
综合类   9篇
预防医学   25篇
眼科学   16篇
药学   101篇
中国医学   1篇
肿瘤学   188篇
  2024年   2篇
  2023年   13篇
  2022年   13篇
  2021年   29篇
  2020年   37篇
  2019年   40篇
  2018年   46篇
  2017年   27篇
  2016年   37篇
  2015年   47篇
  2014年   55篇
  2013年   53篇
  2012年   95篇
  2011年   89篇
  2010年   77篇
  2009年   63篇
  2008年   101篇
  2007年   118篇
  2006年   107篇
  2005年   102篇
  2004年   86篇
  2003年   94篇
  2002年   95篇
  2001年   25篇
  2000年   23篇
  1999年   22篇
  1998年   25篇
  1997年   24篇
  1996年   15篇
  1995年   17篇
  1994年   17篇
  1993年   19篇
  1992年   19篇
  1991年   15篇
  1990年   14篇
  1989年   17篇
  1988年   8篇
  1987年   8篇
  1986年   7篇
  1985年   8篇
  1984年   5篇
  1983年   7篇
  1982年   6篇
  1981年   3篇
  1980年   5篇
  1978年   1篇
  1967年   1篇
  1963年   1篇
排序方式: 共有1738条查询结果,搜索用时 15 毫秒
51.
To investigate changes in the incidence of postoperative infections in the surgical department of a teaching hospital. During the 30-year period from September 1987 to August 2017, 11,568 gastroenterological surgical procedures were performed in our surgical department. This 30-year period was divided into seven periods (A–G), ranging from 2 to 7 years each and based on the infection control methods used in each period. We then compared the rates of incisional surgical site infection (SSI) and organ/space SSI; remote infection (RI) including respiratory tract infection (RTI), intravascular catheter-related infection, and urinary tract infection (UTI); and antibiotic-associated colitis caused by methicillin-resistant Staphylococcus aureus (MRSA) enteritis or Clostridioides (Clostridium) difficile-associated disease (CDAD) among the seven periods. In periods B (September 1990–August 1997) and E (November 2004–July 2007), when a unique antibiotic therapy devised in our department was in use, MRSA was isolated from only 0.3% and 0.4% of surgical patients, respectively, and these rates were significantly lower than those in the other periods (p < 0.05). The rate of CDAD increased during period F (August 2007–July 2014), but in period G (August 2014–August 2017), restrictions were placed on the use of antibiotics with a strong anti-anaerobic action and, in this period, the rate of CDAD was only 0.04%, which was significantly lower than that in period F (p < 0.05). Limiting the use of antibiotics that tend to disrupt the intestinal flora may reduce the rates of MRSA infection and CDAD after gastroenterological surgery.  相似文献   
52.
The objective of this study was to investigate in vivo femoro-tibial motion using the movement of femoral flexion axis of a single-radius TKA. We examined 20 clinically successful knees with a single-radius posterior stabilized TKA to evaluate the kinematics of deep knee flexion using 2–3-dimensional registration techniques. The mean knee flexion range of motion was 117.8°. The mean rotation of the femoral component was 7.6° external rotation. The mean knee flexion angle at initial post-cam engagement was 55.2°. No paradoxical movement of femoral component was shown until 70° flexion, afterward the femoral component rolled back with flexion. The data showed that the design of this prosthesis might contribute to reduce the paradoxical anterior femoral movement and provide stability in mid-flexion ranges.  相似文献   
53.

Background

Chronic kidney disease (CKD) is a major global problem and is also associated with a decreased health-related quality of life (HRQOL). The aim of this study was to evaluate measured HRQOL based on the new CKD classification including proteinuria stage, and the effect of measured HRQOL on CKD progression and clinical outcomes over a 3-year period.

Methods

EuroQol (EQ-5D), a generic preference-based questionnaire, was administered to 537 CKD outpatients at the University of Tsukuba Hospital between November and December 2008. We evaluated disease progression in CKD patients including the incidence of end-stage kidney disease (ESKD), cardiovascular disease (CVD) and all-cause mortality over a 3-year follow-up period.

Results

The proportions progressing to the higher stages were 32.6, 20.0, 36.6, 39.5, and 45.8 % from glomerular filtration rate (GFR) stages (G) 1–4, respectively. The proportion progressing to ESKD (G5D) was 0.7 % from G2, 3.9 % from G3b, 20.8 % from G4 and 63.4 % from G5. The incidence of CVD and/or death was 1.2, 4.6, 4.9, 5.3, 8.3 and 21.1 % from G1?G5, respectively. The quality-adjustment weights at G4–5 were significantly lower than at G1–2 and the weights at proteinuria stage (A) 3 were significantly lower than at A1–2. The quality-adjustment weights of patients with events such as 50 % estimated GFR decline, dialysis, CVD, and/or death were significantly lower than those without events.

Conclusion

We showed CKD progression and clinical outcomes over a 3-year period. Quality-adjustment weights in CKD patients were associated with not only disease progression such as initiation of dialysis treatment and incidence of CVD events and all-cause death, but also the level of proteinuria at baseline.  相似文献   
54.
55.
Sclerosing cholangitis is heterogeneous in its etiopathogenesis. Recently, sclerosing cholangitis showing abundant immunoglobulin (Ig)G4+ plasma cell infiltration was added to the sclerosing cholangitis group. This form was frequently associated with sclerosing pancreatitis (autoimmune pancreatitis) and also occasionally with other diseases such as chronic sclerosing sialadenitis, all of which falls within IgG4-related sclerosing disease. Herein, this new member, called IgG4-related sclerosing cholangitis (IgG4-SC), is reviewed. IgG4-SC shows grossly medullary and fleshy lesions along the biliary tree, and histologically marked lymphoplasmacytic infiltration with extensive fibrosis, and obliterative phlebitis, sharing histopathological features with sclerosing pancreatitis. Peribiliary glands are also severely affected. Interestingly, hepatic inflammatory pseudotumor (HIP) is not infrequently associated with IgG4-SC, and is thought as a local exaggeration of IgG4-SC. Immunohistochemically, many IgG4+ plasma cells and CD4+/CD25+ regulatory T cells are found around the affected bile ducts and portal tracts. Incontrast, these cells are scarce in the affected bile ducts of primary sclerosing cholangitis (PSC), a prototype of sclerosing cholangitis. Biliary lining epithelia are relatively spared in IgG4-SC in comparison with those of PSC showing degeneration and ulceration. In some cases of IgG4-SC, IgG4+ plasma cells are also found considerably in small portal tracts, so needle liver biopsy is useful for the diagnosis of IgG4-SC. Therapeutically, IgG4-SC responds well to steroid therapy, while such character is not reported in PSC. Taken together, IgG4-SC may be etiologically different from PSC, and immunopathological processes relating to IgG4 and regulatory T cells may be involved in the pathogenesis of IgG4-SC. Further studies are needed to clarify the etiopathogenesis of IgG4-SC and its related disorders.  相似文献   
56.

Background

Previous studies suggest that the pathophysiology of heart failure with preserved ejection fraction (HFpEF) is characterized not only by high ventricular stiffness, but also by vascular stiffness. Azilsartan has higher vascular affinity compared with other angiotensin II receptor blockers (ARBs), which were proven to have no beneficial effects on clinical outcomes in patients with HFpEF in earlier clinical trials. We aimed to test the hypothesis that azilsartan may improve left ventricular diastolic function in HFpEF patients with hypertension in this trial.

Methods

The Effects of Angiotensin Receptor Blockers on Diastolic Function in Patients Suffering from Heart Failure with Preserved Ejection Fraction: J-TASTE trial is a multicenter, randomized, open-labeled, and assessor(s)-blinded, active controlled using candesartan, parallel-group clinical trial, to compare changes in left ventricular (LV) diastolic dysfunction between HFpEF patients with hypertension who have received candesartan or azilsartan for 48 weeks. The primary endpoint is the change in early diastolic wave height/early diastolic mitral annulus velocity (E/e’) assessed by echocardiography from the baseline to the end of the study (48 weeks). A total of 190 patients will be recruited into the study.

Conclusions

The design of the J-TASTE trial will provide data on whether differences between the effects of the two tested drugs on LV diastolic function exist in HFpEF patients with hypertension and will improve understanding of the pathophysiological role of vascular stiffness on diastolic function.
  相似文献   
57.
BACKGROUND/AIMS: Thioredoxin (TRX) is a stress-inducible thiol-containing protein. The aim of this study was to evaluate the clinical significance of serum TRX in patients with nonalcoholic steatohepatitis (NASH) or simple steatosis. METHODS: Serum TRX levels were determined using an enzyme-linked immunosorbent assay kit in 25 patients with NASH, 15 patients with simple steatosis, and 17 healthy volunteers. RESULTS: Serum TRX levels (medians and (ranges), ng/ml) were significantly elevated in patients with NASH (60.3 (17.6-104.7)), compared to those in patients with simple steatosis (24.6 (16.6-69.7), P=0.0009) and in healthy controls (23.5 (1.3-50.7), P<0.0001). Serum ferritin levels in patients with NASH were also significantly higher than the levels in patients with simple steatosis. The receiver operating characteristic curve confirmed that serum TRX and ferritin levels were predictors for distinguishing NASH from simple steatosis. Higher grades of histological iron staining were observed in NASH than in simple steatosis. Serum TRX tended to increase in accordance with hepatic iron accumulation and the histological severity in patients with NASH. CONCLUSIONS: The pathogenesis of NASH may be associated with iron-related oxidative stress. The serum TRX level is a parameter for discriminating NASH from simple steatosis as well as a predictor of the severity of NASH.  相似文献   
58.
59.
We herein describe a 60-year-old Japanese man with a giant retroperitoneal liposarcoma undergoing leiomyosarcomatous differentiation. He was admitted to our hospital because of a 5-month history of dysphagia and abdominal distention. Abdominal computed tomography showed a giant tumor that occupied the entire retroperitoneal space. The majority of the mass was lipomatous and low density; both a heterogenous and solid mass were also present. A giant retroperitoneal liposarcoma was diagnosed, and tumor resection was performed. At surgery, the tumor was mostly isolated from the retroperitoneum and other organs. Histopathologically, the tumor comprised well-differentiated and dedifferentiated liposarcoma with heterologous differentiation of the leiomyosarcomatous components, which is a rare phenomenon in liposarcoma. The patient was alive 3 years after the first treatment, although he has had 3 local recurrences (approximately one recurrence yearly) and has been treated by repeated resection and radiotherapy.Key words: Retroperitoneum, Liposarcoma, Leiomyosarcomatous differentiationDedifferentiated liposarcoma (DL) is one of the most frequent sarcomas of the retroperitoneum. It is defined by the association of an atypical lipomatous tumor, namely, areas of well-differentiated liposarcoma (WDL), with a dedifferentiated component. WDL is composed of mature adipocytes and atypical stromal cells with an enlarged, hyperchromatic nucleus. Usually, the dedifferentiated part of the liposarcoma is composed of either a spindle/pleomorphic high-grade sarcoma or a mixoid/spindle cell low-grade sarcoma. The WDL component may be easily overlooked, and DL may thus be mistaken for another high-grade sarcoma. It has been reported in one study that approximately 5% of the dedifferentiated component showed heterologous differentiation, such as leiomyosarcoma, rhabdomyosarcoma, osteosarcoma, and angiosarcoma.1 A less common phenomenon is the occurrence of WDL with leiomyosarcomatous (LMS) differentiation.2 Limited to the retroperitoneum, only 8 cases of liposarcoma with LMS components have been reported.37 We herein report a case of retroperitoneal liposarcoma comprising WDL and DL, with LMS components, treated by surgical resection.  相似文献   
60.
Vertebral fracture (VFx) is associated with various co-morbidities and increased mortality. In this paper, we have studied the detective value of height loss for VFx using two indices; historical height loss (HHL) which is the difference between the maximal height, and the current height (CH), and CH/knee height (KH) ratio. One-hundred and fifty-one postmenopausal women visiting the outpatient clinic of orthopaedics were studied for their CH, self-reported maximal height, KH, and radiographically diagnosed VFx number(s). VFx was present in 41.1 % of the subjects. Multiple regression analyses revealed that the number of prevalent fractures was a significant predictor of HHL and CH/KH ratio. Receiver operator characteristic curve analysis has shown that for HHL, the area under the curve (AUC) with their 95 %CI in the parentheses was 0.84 (0.77, 0.90), 0.88 (0.83, 0.94), and 0.91 (0.86, 0.96) for ≥1, ≥2, and ≥3 fractures, respectively. For the presence of ≥1 VFx, the cut-off value was 4.0 cm (specificity 79 %; sensitivity 79 %). Regarding the CH/KH ratio, AUC was 0.73 (0.65, 0.82), 0.85 (0.78, 0.93), and 0.91 (0.86, 0.96) for ≥1, ≥2, and ≥3 fractures, respectively. For the presence of ≥1 VFx, the cut-off value was 3.3 (specificity 47 %; sensitivity 91 %). Both cut-off values for HHL and CH/KH ratio had high negative predictivity across the wide range of theoretical VFx prevalence. Thus, HHL and CH/KH were both good detectors of VFx. Our data would be the basis to determine the cut-off value for the screening or case finding of subjects with VFx.  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