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   8336篇
  免费   376篇
  国内免费   31篇
耳鼻咽喉   53篇
儿科学   116篇
妇产科学   210篇
基础医学   1134篇
口腔科学   182篇
临床医学   529篇
内科学   1799篇
皮肤病学   146篇
神经病学   657篇
特种医学   501篇
外科学   1237篇
综合类   38篇
一般理论   2篇
预防医学   378篇
眼科学   158篇
药学   744篇
中国医学   21篇
肿瘤学   838篇
  2023年   43篇
  2022年   55篇
  2021年   193篇
  2020年   88篇
  2019年   128篇
  2018年   148篇
  2017年   131篇
  2016年   146篇
  2015年   139篇
  2014年   193篇
  2013年   267篇
  2012年   436篇
  2011年   509篇
  2010年   293篇
  2009年   220篇
  2008年   416篇
  2007年   518篇
  2006年   474篇
  2005年   449篇
  2004年   372篇
  2003年   358篇
  2002年   424篇
  2001年   223篇
  2000年   262篇
  1999年   246篇
  1998年   126篇
  1997年   87篇
  1996年   82篇
  1995年   59篇
  1994年   54篇
  1993年   43篇
  1992年   156篇
  1991年   148篇
  1990年   140篇
  1989年   124篇
  1988年   122篇
  1987年   107篇
  1986年   103篇
  1985年   100篇
  1984年   56篇
  1983年   49篇
  1981年   28篇
  1979年   57篇
  1975年   30篇
  1974年   26篇
  1973年   28篇
  1972年   34篇
  1971年   26篇
  1969年   34篇
  1968年   28篇
排序方式: 共有8743条查询结果,搜索用时 562 毫秒
1.
Journal of Thrombosis and Thrombolysis - Amniotic fluid embolism (AFE) is a catastrophic condition in the peripartum period and still remains as a leading cause of maternal death. Although over 80%...  相似文献   
2.
The association between kidney function and cancer incidence is inconsistent among previous reports, and data on the Japanese population are lacking. It is unknown whether kidney function modifies the cancer risk of other factors. We aimed to evaluate the association of estimated glomerular filtration rate (eGFR) with cancer incidence and mortality in 55 242 participants (median age, 57 years; 55% women) from the Japan Multi-Institutional Collaborative Cohort Study. We also investigated differences in cancer risk factors between individuals with and without kidney dysfunction. During a median 9.3-year follow-up period, 4278 (7.7%) subjects developed cancer. Moderately low and high eGFRs were associated with higher cancer incidence; compared with eGFR of 60-74 ml/min/1.73 m2, the adjusted hazard ratios (HRs) (95% confidence intervals [CIs]) for eGFRs of ≥90, 75-89, 45-59, 30-44 and 10-29 ml/min/1.73 m2 were 1.18 (1.07-1.29), 1.09 (1.01-1.17), 0.93 (0.83-1.04), 1.36 (1.00-1.84) and 1.12 (0.55-2.26), respectively. High eGFR was associated with higher cancer mortality, while low eGFR was not; the adjusted subdistribution HRs (95% CIs) for eGFRs of ≥90 and 75-89 ml/min/1.73 m2 were 1.58 (1.29-1.94) and 1.27 (1.08-1.50), respectively. Subgroup analyses of participants with eGFRs ≥60 and <60 ml/min/1.73 m2 revealed elevated cancer risks of smoking and family history of cancer in those with eGFR <60 ml/min/1.73 m2, with significant interactions. Our findings suggest that the relationship between eGFR and cancer incidence was U-shaped. Only high eGFR was associated with cancer mortality. Kidney dysfunction enhanced cancer risk from smoking.  相似文献   
3.
4.
5.
6.
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   
7.
The phosphodiesterase-5 (PDE-5) inhibitor, sildenafil, has been reported to produce sustained pulmonary vasodilatation in patients with pulmonary hypertension (PH). Recently, vardenafil, a more potent and selective PDE-5 inhibitor than sildenafil, has been approved for the treatment of erectile dysfunction. However, the long-term effects of oral vardenafil in patients with PH are unknown. We studied five consecutive patients with PH; one with primary pulmonary hypertension, two with chronic pulmonary thromboembolism, one with Eisenmenger syndrome (ventricular septal defect) and one with secondary pulmonary hypertension after a ventricular septal defect closure operation. In an acute hemodynamic trial, vardenafil (5 mg) significantly decreased both the pulmonary vascular resistance (PVR) and systemic vascular resistance (SVR) with an increase in cardiac output. In a chronic hemodynamic trial, the maintenance dose of vardenafil (10 to 15 mg) for 3 months significantly decreased the PVR, but not the SVR, with a 20.7% reduction of the PVR/ SVR ratio. Plasma brain natriuretic peptide (BNP) levels were also significantly decreased after 3 months. This pilot study demonstrates that long-term oral vardenafil therapy may be a safe and effective treatment for patients with PH.  相似文献   
8.
A prognosis of patients with a curative resected advanced cancer of the lower gastric region was worse than that of the other region of the stomach. The 5 year survival rate was only 47.3%. One of the main reasons was that a rate of lymph node recurrence was higher. In this point of view, we studied on lymphatic flow of the lower gastric region using an activated carbon particle (CH40). Lymph nodes were stained black soon after the injection of CH40 into the lower gastric wall at laparotomy. The black stained rate of an each regional lymph node was as follows. 3. 58%, 4. 17%, 5. 50%, 6. 25%, 1. 21%, 7. 58%, 8. 83%, 9. 58%, 11. 17% and 12. 33% in case of injection into the greater curvature and and 4. 31%, 6. 100%, 8. 25%, 9. 25%, 14V and 56% in case of injection into the lesser curvature. The stained rate was relatively high in 12 and 14V lymph node which we had not routinely dissected. The rates of lymph nodes stained black were related to those of cancer metastasis. The results suggest that lymphadenectomy of 12 for the cancer at the lesser curvature and that of 14V for the cancer at the greater curvature might make a prognosis of lower gastric cancer better.  相似文献   
9.
A clinical phase I study for T-2588 was carried out in 25 healthy male volunteers. Each volunteer received T-2588 in one of the following doses: 100 mg capsule or tablet as a single oral administration in fasting or non-fasting state, 200 or 400 mg capsule as a single oral administration in non-fasting state or 300 or 600 mg daily for 14 approximately 15 days as a repeated administration in non-fasting state. The results are summarized below. No subjective or objective adverse effects were noted after a single oral administration. But repeated dose of 300 mg daily for 15 days and 600 mg daily for 14 days brought about abdominal distension in 1 case and soft stool in 1 case, respectively. As an abnormal change in clinical laboratory findings, 1 case with slight increase in transaminase after a single administration and 3 cases with slight increases in transaminase after repeated doses were observed. Time to reach a maximum concentration of T-2525 in blood (Tmax) was longer in subjects at non-fasting states than subjects in fasting states. Maximum blood concentration was lower in the latter than in the former. Urinary excretion rate in 8 hours after an oral administration was 19 approximately 28% and it was higher in non-fasting subject than in fasting subject. No accumulation of T-2588 was noted after repeated doses.  相似文献   
10.
Recently an essential role of interstitial cells of Cajal (ICC) within myenteric plexus (ICC-MY) was suggested in ascending contraction and descending relaxation in the mouse ileum. The role of ICC in these neural reflexes was examined in the distal colonic segments prepared from the wild type and c-kit mutant, W/W(V) mice, in the present study. Localized distension of the segments from the wild type mice by using a small balloon resulted in ascending contraction and descending relaxation. In the segments from the mutant mice, localized distension also induced these neural reflexes similar to those observed in the wild type mice. Immunohistochemical examination demonstrated that ICC-MY and ICC present in muscle layers (ICC-IM) were severely disrupted in the mutant mouse, but only ICC, present within submucosal plexus (ICC-SMP), remained unchanged. In the small strips with ICC-SMP absent prepared from the mutant mouse, electrical field stimulation induced contraction or relaxation in the absence or presence of atropine, respectively. It was suggested that ICC have no important role in the ascending and descending neural reflexes in the mouse distal colon, this is in direct contrast to the role of ICC-MY in the ileum.  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