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   5108篇
  免费   279篇
  国内免费   10篇
耳鼻咽喉   31篇
儿科学   362篇
妇产科学   80篇
基础医学   438篇
口腔科学   180篇
临床医学   323篇
内科学   1135篇
皮肤病学   268篇
神经病学   294篇
特种医学   124篇
外科学   741篇
综合类   186篇
预防医学   244篇
眼科学   308篇
药学   431篇
中国医学   13篇
肿瘤学   239篇
  2023年   38篇
  2022年   76篇
  2021年   169篇
  2020年   75篇
  2019年   152篇
  2018年   188篇
  2017年   130篇
  2016年   157篇
  2015年   165篇
  2014年   211篇
  2013年   224篇
  2012年   384篇
  2011年   447篇
  2010年   233篇
  2009年   177篇
  2008年   246篇
  2007年   284篇
  2006年   207篇
  2005年   196篇
  2004年   170篇
  2003年   142篇
  2002年   159篇
  2001年   109篇
  2000年   114篇
  1999年   90篇
  1998年   41篇
  1997年   19篇
  1996年   20篇
  1995年   35篇
  1994年   17篇
  1992年   69篇
  1991年   64篇
  1990年   41篇
  1989年   37篇
  1988年   53篇
  1987年   39篇
  1986年   32篇
  1985年   38篇
  1984年   27篇
  1983年   23篇
  1979年   22篇
  1977年   15篇
  1975年   16篇
  1974年   26篇
  1973年   15篇
  1972年   27篇
  1971年   19篇
  1970年   15篇
  1969年   16篇
  1968年   18篇
排序方式: 共有5397条查询结果,搜索用时 15 毫秒
971.
972.
Limited information is available on the role of iron in fatty acid metabolism in humans. We hypothesized that iron supplementation will increase desaturase activity, and so, the aim of this study was to determine the effect of iron supplementation on fatty acid desaturase activity in young women. Participants were randomly assigned to a control group (CG) or supplementation group (SG) who were provided with 37.4 mg of elemental iron daily for 12 weeks. Forty women completed the trial, n = 19 in CG and n = 21 in SG. The mean ages were 25.2 and 24.6 years, and body mass indices were 21.8 and 21.2 (kg/m2) in CG and SG, respectively. Serum ferritin concentrations increased significantly (P < .01) in subjects assigned to SG but were unchanged in CG. Serum iron concentrations were not significantly changed. Plasma zinc concentrations at the end of the intervention were similar to baseline values for individuals in CG but were decreased significantly (P = .004) in SG. Plasma fatty acids, phospholipid fatty acids, and desaturase activities, expressed as precursor-to-product ratios, were not significantly affected by the intervention, although in SG the concentration of serum ferritin was correlated positively (P < .05) with Δ6-desaturase activity. Supplementing non-anemic women with low dose iron improves iron status but has no significant effect on desaturase activity. The lack of a clear effect on an indirect indicator of desaturase activity may be related to the antagonism between iron and zinc, as illustrated by the decrease in plasma zinc concentrations in women who were supplemented with iron.  相似文献   
973.
Patients with aspergilloma can be safely managed with supportive therapy in absence of massive haemoptysis. We hypothesised that chronic cavitary pulmonary aspergillosis (CCPA) could also be managed on similar grounds. The aim of this prospective, randomised controlled trial was to evaluate the efficacy and safety of itraconazole in CCPA. Consecutive patients of CCPA with presence of chronic pulmonary/systemic symptoms; and pulmonary cavities; and presence of Aspergillus (immunological or microbiological) were randomised to receive either supportive treatment alone or itraconazole 400 mg daily for 6 months plus supportive therapy. Response was assessed clinically, radiologically and overall after 6 months therapy. A total of 31 patients (mean age, 37 years) were randomised to itraconazole (n = 17) or the control (n = 14) group. The number of patients showing overall response was significantly higher in the itraconazole group (76.5%) vs. the control (35.7%) group (P = 0.02). The numbers of patients demonstrating clinical or radiological response were also significantly higher in the itraconazole group (P = 0.016 and 0.01 respectively). Adverse events were noted in eight patients in the itraconazole group, however, none was serious or led to discontinuation of the study drug. Itraconazole was found to be superior to standard supportive treatment alone in stabilising cases of CCPA. (clinicaltrials.gov; NCT01259336).  相似文献   
974.
PurposeTreatment of locally advanced non-small cell lung cancer (LA-NSCLC) involves definitive chemoradiation therapy (CRT) or neoadjuvant CRT and resection, but radiation treatment volumes remain in question. With CRT, involved-field radiation therapy (IFRT) is replacing elective nodal irradiation, reducing toxicity, and allowing dose escalation. However, prior reports of IFRT describe failures only after radical CRT; with improved local control after resection, IFRT may lead to more regional recurrences. Our objective is to evaluate pattern-of-failure in patients with LA-NSCLC treated with split-course IFRT, chemotherapy, and subsequent surgery.Methods and MaterialsPatients treated between December 2004 and 2010 were included. Imaging scans demonstrating failure were fused into the radiation therapy planning computed tomography, and recurrent nodes were contoured to determine pattern-of-failure (involved versus elective nodal failure [INF vs ENF]). Locoregional progression-free survival and distant metastasis-free survival were calculated using Kaplan-Meier methodology. The cumulative incidence of regional recurrence (CIRR) was determined with death as a competing risk.ResultsForty-five patients met inclusion criteria, and patients with RR had a lower rate of pN0 than those without RR (20% vs 60%, P = .02). With a median follow-up of 2.9 years, median survival was not reached, and 3-year locoregional progression-free survival and distant metastasis-free survival were 53% and 35%, respectively. Two and 3-year CIRR were 25% and 33%, respectively. There were no local failures. Thirteen (29%) patients had RR, 8 with INF only and 5 with ENF alone or both, totaling 27 recurrences. Only 2 (4%) ENF occurred without INF, both with distant metastasis, and no elective node was the first and only site of failure.ConclusionsOur data suggest that IFRT does not compromise regional control in the neoadjuvant management of LA-NSCLC. Tailoring nodal volumes may improve treatment-related morbidity and allow for dose intensification of involved nodes. Further research is necessary to improve regional and distant control.  相似文献   
975.
We describe the case of a 48-year-old man who, after a 5-year history of recurrent infection and intermittent trismus associated with a deeply impacted lower right third molar tooth, presented to the accident and emergency department with severely limited mouth opening, extensive facial swelling and pyrexia. The lower right third molar was later removed successfully through a sagittal split ramus osteotomy approach. This case shows that the sagittal split osteotomy continues to have a valuable role in the removal of deeply impacted lower third molars, particularly when they are in close proximity to the inferior alveolar nerve.  相似文献   
976.
977.
978.
979.
IntroductionErectile dysfunction (ED) and coronary artery disease (CAD) often share common risk factors, and there is growing evidence that ED might serve as a clinical marker for cardiovascular disease. Despite rising trends of CAD in Asian Indians, limited data are available on the prevalence of ED and its correlation with CAD severity in such patients.AimTo study the prevalence of ED in Asian Indian patients undergoing coronary angiography and to assess if the severity of ED correlates with angiographic severity of CAD.MethodsIn all patients undergoing coronary angiography, ED was assessed using the International Index of Erectile Function‐5 questionnaire.Main Outcome Measures and ResultsAmong 175 male patients, ED was present in 70%; patients with ED had a higher incidence of multivessel CAD (80% vs. 36%, P 0.001), diffuse CAD (81% vs. 34%, P 0.001), and higher number of mean coronary vessels involved compared with those without ED. Those with severe ED had higher prevalence of multivessel CAD and higher number of mean coronary vessels involved compared with those with milder grades of ED. Onset of symptoms of ED preceded symptoms of CAD by a mean of 24.6 months in 84% of patients. The presence of severe ED was associated with a 21‐fold higher risk of having triple‐vessel disease (odds ratio [OR] 21.94, 95% confidence interval [CI] 3.41–141.09, P = 0.001) and an 18‐fold higher risk of having diffuse angiographic CAD (OR 17.91, 95% CI 3.11–111.09, P = 0.001).ConclusionAsian Indians with angiographic CAD frequently have ED; symptoms of ED precede that of CAD in most patients. Incidence of multivessel and diffuse CAD is significantly more common in patients with ED. It is important for physicians to be aware of the close relationship between the two conditions so that patients with ED can have optimal risk stratification for concomitant CAD whenever required.  相似文献   
980.
Hormone profile in leprosy   总被引:1,自引:0,他引:1  
Hormone profile were carried out in 35 male cases of leprosy. They were divided into tuberculoid leprosy, borderline leprosy, lepromatous leprosy and lepra reaction. Serum testosterone, follicle-stimulating hormone, Luteinizing hormone, and Oestradiol level were measured in these cases of leprosy. It was observed that serum testosterone were significantly low in lepromatous leprosy (P less than 0.001) and lepra reaction (P less than 0.01). The serum levels of follicle-stimulating hormone and luteinizing hormone were significantly high in lepromatous leprosy (P less than 0.02) and lepra reaction (P less than 0.05). Serum Oestradiol was raised in approx. 60% cases in borderline leprosy, lepromatous leprosy and lepra reaction.  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