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   1859篇
  免费   120篇
  国内免费   24篇
耳鼻咽喉   7篇
儿科学   38篇
妇产科学   17篇
基础医学   312篇
口腔科学   22篇
临床医学   187篇
内科学   312篇
皮肤病学   15篇
神经病学   242篇
特种医学   30篇
外科学   180篇
综合类   102篇
预防医学   185篇
眼科学   32篇
药学   140篇
  1篇
中国医学   33篇
肿瘤学   148篇
  2024年   4篇
  2023年   19篇
  2022年   40篇
  2021年   57篇
  2020年   34篇
  2019年   35篇
  2018年   45篇
  2017年   24篇
  2016年   47篇
  2015年   62篇
  2014年   61篇
  2013年   87篇
  2012年   136篇
  2011年   132篇
  2010年   74篇
  2009年   67篇
  2008年   104篇
  2007年   125篇
  2006年   130篇
  2005年   95篇
  2004年   78篇
  2003年   96篇
  2002年   90篇
  2001年   15篇
  2000年   28篇
  1999年   28篇
  1998年   30篇
  1997年   17篇
  1996年   21篇
  1995年   17篇
  1994年   14篇
  1993年   13篇
  1992年   16篇
  1991年   8篇
  1990年   7篇
  1989年   5篇
  1988年   5篇
  1987年   9篇
  1986年   4篇
  1985年   8篇
  1984年   9篇
  1983年   11篇
  1981年   13篇
  1980年   6篇
  1978年   7篇
  1977年   4篇
  1975年   4篇
  1974年   4篇
  1971年   5篇
  1970年   4篇
排序方式: 共有2003条查询结果,搜索用时 15 毫秒
61.
A 71-years-old man presented with an incidentally finding of a tumor in the left pulmonary apex that measured approximately 4.5 cm of diameter. The patient, had de preceding of chronic smoking. Bronchoscopy with biopsy by transthoracic punction suggested the presence of epidermoid carcinoma. In the radiologic control, an increase in tumor size from 4.5 cm to 5 cm of the lesion was observed in a period of three months. The patient was submited to surgery and a tumorectomy by posterolateral thoracotomy was performed. The postoperatory evolution was satisfactory. The final diagnosis was hamartoma of the lung.  相似文献   
62.
This article pays homage to Sergei Nicolai Korotkoff, for the centenary of the auscultatory method discovery. It refers to his discover of blood pressure auscultatory method in Russia, in 1905; presents the evidence that resulted in the development of sphygmomanometry studies in Brasil; describes the important contribution of the Nursing School of the University of S?o Paulo to the development of blood pressure measurement research; and analyses the results of the research field of "Cuff width influence in blood pressure measurement", created at the Nursing School of The University of S?o Paulo, in 1974. The scientific results of doctoral studies are presented, identifying the research groups that are contributing to defying knowledge in this area. The article demonstrates the consolidation of the results related to the initial doctoral program studies developed in the area. Confirmation of hypothesis in longitudinal studies is emphasized.  相似文献   
63.
World Journal of Surgery - There are complex barriers that increase delays to surgical care in low- and middle-income countries, particularly among the vulnerable population of children....  相似文献   
64.
65.
IntroductionAlthough hyperferritinemia may reflect the inflammatory status of patients with non-alcoholic fatty liver disease (NAFLD), approximately 33% of hyperferritinemia cases reflect real hepatic iron overload.AimTo evaluate a non-invasive method for assessing mild iron overload in patients with NAFLD using 3T magnetic resonance imaging (MRI) relaxometry, serum hepcidin, and the expression of ferritin subunits.MethodsThis cross-sectional study assessed patients with biopsy-proven NAFLD. MRI relaxometry was performed using a 3T scanner in all patients, and the results were compared with iron content determined by liver biopsy. Ferritin, hepcidin, and ferritin subunits were assessed and classified according to ferritin levels and to siderosis identified by liver biopsy.ResultsA total of 67 patients with NAFLD were included in the study. MRI revealed mild iron overload in all patients (sensitivity, 73.5%; specificity, 70%). For mild (grade 1) siderosis, the transverse relaxation rate (R2*) threshold was 58.9 s?1 and the mean value was 72.5 s?1 (SD, 33.9), while for grades 2/3 it was 88.2 s?1 (SD, 31.9) (p < 0.001). The hepcidin threshold for siderosis was > 30.2 ng/mL (sensitivity, 87%; specificity, 82%). Ferritin H and ferritin L subunits were expressed similarly in patients with NAFLD, regardless of siderosis. There were no significant differences in laboratory test results between the groups, including glucose parameters and liver function tests.ConclusionsMRI relaxometry and serum hepcidin accurately assessed mild iron overload in patients with dysmetabolic iron overload syndrome.  相似文献   
66.
Allylmercaptocaptopril: a new antihypertensive drug   总被引:3,自引:0,他引:3  
Allylmercaptocaptopril (CPSSA) was synthesized by reacting captopril with pure allicin. Fructose-induced hypertensive groups of rats were fed a fructose-rich diet for 3 weeks, and then received the diet plus either CPSSA (40 to 56 mg or 138 to 194 micromol/L/kg/d) or captopril (80 mg or 369 micromol/L/kg/d) for 2 more weeks. CPSSA (both doses) significantly lowered blood pressure (BP) from 153.4 to 120.8 mm Hg (P <.005). Captopril gave similar results, lowering BP from 150.7 to 123 mm Hg (P <.005). CPSSA also decreased the high levels of triglycerides to normal. The new stable compound allylmercaptocaptopril combines the beneficial properties of captopril and allicin and is a potential candidate for antihypertensive drug therapy.  相似文献   
67.
A Western blot method that uses antigens from culture promastigote forms of Leishmania (Viannia) braziliensis, L. (Leishmania) amazonensis, L. (Leishmania) tropica, and a trypanosomatid (strain 268T) isolated from naturally infected tomatoes was evaluated for laboratory diagnosis of American tegumentary leishmaniasis (ATL). Serum samples were obtained from 108 patients with ATL (group I), 23 chagasic patients (group II), 32 patients with other diseases (group III), and 78 healthy individuals (group IV). The overall analysis showed a sensitivity of 76.90%, 90.40%, 78.50%, and 87.90%, a specificity of 100%, 93.80%, 87.80%, and 77.10%, a positive predictive value of 100%, 94.00%, 89.50%, and 72.50%, a negative predictive value of 75.70%, 90.00%, 75.40%, and 90.20%, and a concordance coefficient kappa of 0.7358, 0.8400, 0.6491, and 0.6287 for L. (V.) braziliensis, L. (L.) amazonensis, L. (L.) tropica, and strain 268T antigens, respectively. The antigenic profile recognized by serum samples from patients with ATL and with Chagas' disease permits serologic distinction between these infections.  相似文献   
68.

Purpose

Hospitalization for acute colonic diverticulitis has become more and more frequent. We studied the changes in the rate of admission and incidence of the disease during the last 25 years.

Methods

We performed a retrospective analysis of all cases treated for acute diverticulitis during 1988–2012 at one hospital serving a defined population in Mid-Norway. The study made a distinction between admission rates and incidence rates. The admission rates defined the total number of cases admitted, while the incidence rates defined the number of new patients hospitalized for acute diverticulitis (first admission). Poisson regression was used to analyse factors associated with diverticulitis incidence rates.

Results

A total of 851 admissions in 650 different patients were identified, with an overall admission rate of 38.5 (CI 35.9 to 41.1) per 100,000 person-years. The admission rate increased from 17.9 (CI 14.1 to 22.3)/100,000 during 1988–1992 to 51.1 (CI 44.8 to 58.0)/100,000 during 2008–2012. Poisson regression analysis showed a significant increase in admission rates with a factor of 2.8 (C.I. 2.2 to 3.5) during 25 years. The overall incidence rate (IRR) of new patients was 29.4 (CI 27.1 to 31.7)/100,000 person-years. IRR increased significantly with a factor of 2.6 (CI 1.96 to 3.34) during 25 years, while IRR for perforations increased even more, by a factor of 3.3 (CI 1.24 to 8.58).

Conclusion

The hospital admission rates as well as incidence rates for acute colonic diverticulitis increased significantly during the 25-year time span.  相似文献   
69.
Patients presenting late in the course of kidney disease who require urgent initiation of dialysis have traditionally received temporary vascular catheters followed by hemodialysis. Recent changes in Medicare payment policy for dialysis in the USA incentivized the use of peritoneal dialysis (PD). Consequently, the use of more expeditious PD for late-presenting patients (urgent-start PD) has received new attention. Urgent-start PD has been shown to be safe and effective, and offers a mechanism for increasing PD utilization. However, there has been no assessment of the dialysis-related costs over the first 90 days of care.The objective of this study was to characterize the costs associated with urgent-start PD, urgent-start hemodialysis (HD), or a dual approach (urgent-start HD followed by urgent-start PD) over the first 90 days of treatment from a provider perspective.A survey of practitioners from 5 clinics known to use urgent-start PD was conducted to provide inputs for a cost model representing typical patients. Model inputs were obtained from the survey, literature review, and available cost data. Sensitivity analyses were also conducted.The estimated per patient cost over the first 90 days for urgent-start PD was $16,398. Dialysis access represented 15% of total costs, dialysis services 48%, and initial hospitalization 37%. For urgent-start HD, total per patient costs were $19,352, and dialysis access accounted for 27%, dialysis services 42%, and initial hospitalization 31%. The estimated cost for dual patients was $19,400.Urgent-start PD may offer a cost saving approach for the initiation of dialysis in eligible patients requiring an urgent-start to dialysis.  相似文献   
70.
心血管疾病是威胁女性健康的头号杀手,女性绝经后心血管疾病风险明显升高,防治现状不容乐观。绝经激素治疗可有效缓解绝经相关症状、生殖泌尿道萎缩相关问题及骨质疏松,但外源性给予雌孕激素能否起到心血管保护作用颇具争议。本文对相关临床证据和国内外指南推荐进行综述。  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