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   3405篇
  免费   270篇
  国内免费   14篇
耳鼻咽喉   34篇
儿科学   60篇
妇产科学   69篇
基础医学   475篇
口腔科学   33篇
临床医学   351篇
内科学   975篇
皮肤病学   117篇
神经病学   246篇
特种医学   112篇
外科学   531篇
综合类   42篇
一般理论   1篇
预防医学   154篇
眼科学   62篇
药学   189篇
中国医学   1篇
肿瘤学   237篇
  2023年   12篇
  2022年   28篇
  2021年   63篇
  2020年   45篇
  2019年   76篇
  2018年   83篇
  2017年   41篇
  2016年   72篇
  2015年   87篇
  2014年   137篇
  2013年   169篇
  2012年   244篇
  2011年   269篇
  2010年   130篇
  2009年   121篇
  2008年   215篇
  2007年   214篇
  2006年   178篇
  2005年   184篇
  2004年   190篇
  2003年   173篇
  2002年   126篇
  2001年   25篇
  2000年   25篇
  1999年   25篇
  1998年   39篇
  1997年   25篇
  1996年   25篇
  1995年   21篇
  1994年   23篇
  1993年   27篇
  1992年   33篇
  1991年   23篇
  1990年   28篇
  1989年   39篇
  1988年   33篇
  1987年   38篇
  1986年   18篇
  1985年   27篇
  1984年   23篇
  1983年   19篇
  1982年   20篇
  1981年   21篇
  1980年   16篇
  1979年   22篇
  1978年   18篇
  1976年   11篇
  1975年   19篇
  1973年   11篇
  1968年   11篇
排序方式: 共有3689条查询结果,搜索用时 468 毫秒
31.
BackgroundEndoscopy plays a pivotal role in the management of adverse events (AE) following bariatric surgery. Leaks, fistulae, and post-operative collection after sleeve gastrectomy (SG) may occur in up to 10% of cases.ObjectivesTo evaluate the efficacy and safety of endoscopic internal drainage (EID) for the management of leak, fistula, and collection following SG.SettingRetrospective, observational, single center study on patients referred from several bariatric surgery departments to an endoscopic referral center.MethodsEID was used as first-line treatment for the management of leaks, fistulae, and collections. Leaks and fistulae were treated with double pigtail stent (DPS) deployment in order to guarantee internal drainage and second intention cavity obliteration. Collections were treated with endoscropic ultrasound (EUS)–guided deployment of DPS or lumen apposing metal stents.ResultsA total of 617 patients (83.3% female; mean age, 43.1 yr) were enrolled in the study for leak (n = 300, 48.6%), fistula (n = 285, 46.2%), and collection (n = 32, 5.2%). Median follow-up was 19.5 months. Overall clinical success was 84.7% whereas 15.3% of cases required revisional surgery after EID failure. Clinical success according to type of AE was 89.5%, 78.5%, and 90% for leak, fistula, and collection, respectively. A total of 10 of 547 (1.8%) presented a recurrence during follow-up. A total of 28 (4.5%) AE related to the endoscopic treatment occurred. At univariate logistic regression predictors of failure were: fistula (OR 2.012), combined endoscopic approach (OR 2.319), need for emergency surgery (OR 1.755), and previous endoscopic treatment (OR 4.818).ConclusionEarly EID for the management of leak, fistula, and post-operative collection after SG seems a safe and effective first-line approach with good long-term results.  相似文献   
32.
Controlled donation after circulatory death (cDCD) is used for “extended criteria” donors with poorer kidney transplant outcomes. The French cDCD program started in 2015 and is characterized by normothermic regional perfusion, hypothermic machine perfusion, and short cold ischemia time. We compared the outcomes of kidney transplantation from cDCD and brain-dead (DBD) donors, matching cDCD and DBD kidney transplants by propensity scoring for donor and recipient characteristics. The matching process retained 442 of 499 cDCD and 809 of 6185 DBD transplantations. The DGF rate was 20% in cDCD recipients compared with 28% in DBD recipients (adjusted relative risk [aRR], 1.43; 95% confidence interval [CI] 1.12–1.82). When DBD transplants were ranked by cold ischemia time and machine perfusion use and compared with cDCD transplants, the aRR of DGF was higher for DBD transplants without machine perfusion, regardless of the cold ischemia time (aRR with cold ischemia time <18 h, 1.57; 95% CI 1.20–2.03, vs aRR with cold ischemia time ≥18 h, 1.79; 95% CI 1.31–2.44). The 1-year graft survival rate was similar in both groups. Early outcome was better for kidney transplants from cDCD than from matched DBD transplants with this French protocol.  相似文献   
33.
PurposeWhile predominant blood supply to the adult patella enters inferomedially, little is known about skeletally immature patellar perfusion. Improved knowledge of immature patella vascularity can further understanding of osteochondritis dissecans, dorsal defects of the patella and bipartite patella, and help ensure safe surgical approaches. We hypothesized that the immature patella would exhibit more uniform blood flow. The study purpose was to quantify immature patella regional perfusion in comparison with adults.MethodsTen cadaveric knees were utilized (five immature, five mature). The superficial femoral artery was cannulated proximally. Signal enhancement increases were compared from pre- to post-contrast MRI to assess relative arterial contributions to patella regions (quadrants, anterior/posterior, superior/inferior, medial/lateral, and outer/inner).ResultsQuantitative-MRI analysis revealed similar distribution of enhancement between the immature and mature patella. The inferior pole exhibited significantly higher arterial contribution versus superior pole in both immature and mature groups (p = 0.009; both groups), while the inferomedial quadrant had the highest arterial contribution of all quadrants in both groups. The superolateral quadrant demonstrated the lowest arterial contribution in the immature group and second lowest in the adult group. The patella outer periphery had significantly greater arterial contribution than the inner central region in both immature (p = 0.009) and mature (p = 0.009) groups.ConclusionDistribution of arterial contributions between the immature and mature patella was similar. Our results highlight the importance of inferior and inferomedial blood supply in both immature and mature patellas. These findings have implications for paediatric and adult patients; surgical damage to inferior patellar vessels should be avoided to prevent associated complications.  相似文献   
34.
35.
36.
We present a case of a rare congenital cardiac anomaly. Magnetic resonance imaging accurately demonstrated a left circumflex aortic arch. This finding was not apparent on a prior conventional angiogram or echocardiography. Magnetic resonance imaging documentation of this anomaly is uncommon. Review of the embryonic development, clinical presentation of complete and incomplete vascular rings, and additional associated cardiac anomalies are discussed. This is one of only a few reported cases of a left circumflex aortic arch. Received: 24 December 1996 Accepted: 15 October 1997  相似文献   
37.
Sixteen polymorphic microsatellite markers were developed for phylogenetic analysis of Leishmania tropica. The phylogenetic tests done demonstrated that they do provide a powerful tool for epidemiological studies. They were also tested for their ability to differentiate strains of other species of Leishmania, confirming that microsatellite markers developed for one leishmanial species cannot generally be used for other leishmanial species. In addition to length variation, a high degree of allelic heterozygosity was seen among the strains investigated, suggestive of sexual recombination within the species L. tropica.  相似文献   
38.
39.
PURPOSE: To investigate variations of circulating serum levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNFalpha), and interleukin-10 (IL-10) during three-dimensional conformal radiation therapy (3D-CRT) in patients with non-small-cell lung cancer and correlate these variations with the occurrence of radiation pneumonitis. PATIENTS AND METHODS: Ninety-six patients receiving 3D-CRT for stage I to III disease were evaluated prospectively. Circulating cytokine levels were determined before, every 2 weeks during, and at the end of treatment. Radiation pneumonitis was evaluated prospectively between 6 and 8 weeks after 3D-CRT. The predictive value of clinical, dosimetric, and biologic (cytokine levels) factors was evaluated both in univariate and multivariate analyses. RESULTS: Forty patients (44%) experienced score 1 or more radiation pneumonitis. No association was found between baseline cytokine levels and the risk of radiation pneumonitis. In the whole population, mean levels of TNFalpha, IL-6, and IL-10 remained stable during radiotherapy. IL-6 levels were significantly higher (P = .047) during 3D-CRT in patients with radiation pneumonitis. In the multivariate analysis, covariations of IL-6 and IL-10 levels during the first 2 weeks of 3D-CRT were evidenced as independently predictive of radiation pneumonitis in this series (P = .011). CONCLUSION: Early variations of circulating IL-6 and IL-10 levels during 3D-CRT are significantly associated with the risk of radiation pneumonitis. Variations of circulating IL-6 and IL-10 levels during 3D-CRT may serve as independent predictive factors for this complication.  相似文献   
40.
Cytomegalovirus (CMV) infection in solid-organ transplantation is associated with increased morbidity and mortality, particularly if a CMV mutant strain with antiviral resistance emerges. Monitoring CMV–specific T cell response could provide relevant information for patient care. We and others have shown the involvement of Vδ2neg γδ T cells in controlling CMV infection. Here, we assessed if Vδ2neg γδ T cell kinetics in peripheral blood predict CMV infection resolution and emergence of a mutant strain in high–risk recipients of kidney transplants, including 168 seronegative recipients receiving organs from seropositive donors (D+R−) and 104 seropositive recipients receiving antithymocyte globulins (R+/ATG). Vδ2neg γδ T cell percentages were serially determined in patients grafted between 2003 and 2011. The growing phase of Vδ2neg γδ T cells was monitored in each infected patient, and the expansion rate during this phase was estimated individually by a linear mixed model. A Vδ2neg γδ T cell expansion rate of ˃0.06% per day predicted the growing phase. The time after infection at which an expansion rate of 0.06% per day occurred was correlated with the resolution of CMV DNAemia (r=0.91; P<0.001). At 49 days of antiviral treatment, Vδ2neg γδ T cell expansion onset was associated with recovery, whereas absence of expansion was associated with recurrent disease and DNAemia. The appearance of antiviral–resistant mutant CMV strains was associated with delayed Vδ2neg γδ T cell expansion (P<0.001). In conclusion, longitudinal surveillance of Vδ2neg γδ T cells in recipients of kidney transplants may predict CMV infection resolution and antiviral drug resistance.  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