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   23277篇
  免费   1656篇
  国内免费   143篇
耳鼻咽喉   199篇
儿科学   832篇
妇产科学   682篇
基础医学   3118篇
口腔科学   374篇
临床医学   2441篇
内科学   4778篇
皮肤病学   495篇
神经病学   2604篇
特种医学   494篇
外科学   2073篇
综合类   152篇
一般理论   37篇
预防医学   3035篇
眼科学   289篇
药学   1438篇
  1篇
中国医学   39篇
肿瘤学   1995篇
  2024年   32篇
  2023年   377篇
  2022年   684篇
  2021年   1204篇
  2020年   755篇
  2019年   989篇
  2018年   1070篇
  2017年   809篇
  2016年   871篇
  2015年   914篇
  2014年   1192篇
  2013年   1436篇
  2012年   2109篇
  2011年   2129篇
  2010年   1099篇
  2009年   937篇
  2008年   1376篇
  2007年   1301篇
  2006年   1207篇
  2005年   1042篇
  2004年   890篇
  2003年   762篇
  2002年   648篇
  2001年   103篇
  2000年   86篇
  1999年   88篇
  1998年   102篇
  1997年   93篇
  1996年   70篇
  1995年   75篇
  1994年   49篇
  1993年   54篇
  1992年   43篇
  1991年   40篇
  1990年   31篇
  1989年   28篇
  1988年   40篇
  1987年   28篇
  1986年   25篇
  1985年   19篇
  1984年   34篇
  1983年   18篇
  1982年   27篇
  1981年   32篇
  1980年   22篇
  1979年   11篇
  1978年   13篇
  1974年   15篇
  1973年   12篇
  1972年   10篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
63.
64.
Children of young and socially disadvantaged parents are more likely to experience adverse outcomes. In response to this, a unique young families’ project in Swansea, UK, was created, which drew together a team of multi-agency professionals, to support people aged 16–24 from 17 weeks of pregnancy throughout 1,001 days of the child's life. The aim of the JIGSO (the Welsh word for Jigsaw) project is for young people to reach their potential as parents and to break the cycle of health and social inequality. This evaluation analysed routinely collected data held by the project from January 2017 to December 2018 exploring health and social outcomes, including smoking and alcohol use in pregnancy, breastfeeding, maternal diet and social services outcomes. Outcomes were compared to local and national averages, where available. Data relating to parenting knowledge and skills were available via records of 10-point Likert scales, one collected at the start of the JIGSO involvement and one around 4–6 months later. Findings showed higher than average levels of breastfeeding initiation and lower smoking and alcohol use in pregnancy. Parents also reported enhanced knowledge and confidence in their child care skills, as well as improved family relationships. Parents with high levels of engagement with JIGSO also appeared to have positive outcomes with Social Services (their child's name was removed from child protection register or their case was closed to social services). This was a post-hoc evaluation, not an intervention study or trial, and thus findings must be interpreted with caution. Despite this, the findings are promising and more prospective research exploring similar services is required.  相似文献   
65.
European Journal of Clinical Microbiology & Infectious Diseases - The aim of this study is to evaluate the chlorhexidine gluconate (CHG) susceptibility in both planktonic cells and biofilm of...  相似文献   
66.
67.
Summary This paper introduces the concept of the resolution matrix as the basis for an objective theoretical comparison of distributed linear inverse solutions to the neuroelectromagnetic inverse problem. In particular, we describe how figures of merit derived from the resolution matrices can be represented graphically to evaluate merits and shortcomings of the different solutions. The use of the figures of merit is illustrated with two solutions that consider minimal a priori information about the generators: Classical Minimum Norm and Backus Gilbert. We recommend to start any analysis with the individual exploration of the resolution kernel for each grid point or at least for those points where the activity is likely to occur. This analysis might help in selecting the optimal inverse for the sources that are supposed to be active in the process under study.This work was supported by a grant from the Deutsche Forschungsgemeinschaft (Klinische Forschergruppe Biomagnetismus and Biosignalanalyse). Partial support was received from Swiss National Foundation grant 4038-044081/1.  相似文献   
68.
This open-label, two-phase cross-over study compared the safety and pharmacokinetics of transdermally administered selegiline and orally administered selegiline hydrochloride in elderly men and women (n = 6/gender). Single oral doses of 10 mg selegiline hydrochloride and single 1/2 and 1 selegiline transdermal system (STS) (delivering similar3.4 and 6.3 mg over 24 h) administered topically were safe and well tolerated in all subjects. Plasma concentrations of selegiline (SEL) and its N-desmethylselegiline (DMS), L-amphetamine (AMP), and L-methamphetamine (MET) metabolites were measured using an HPLC/MS/MS method with lower quantitation limits of 10, 50, 200, and 200 pg/mL, respectively. No significant gender-related differences were observed following single 10-mg oral doses of selegiline hydrochloride or single 24-h applications of 1/2 and 1 STS to elderly males and females. The low level of dermal irritation as assessed by erythema and edema rating scales suggests that the STS was similar to Band-Aid (Johnson & Johnson, Skillman, NJ) controls. The transdermal administration of SEL bypasses the first-pass metabolism, that is significant after oral administration (first-pass extraction >90%). Peak plasma levels of 1.19, 23.22, 4.78, and 14.08 ng/mL were observed for SEL, DMS, AMP, and MET after a single 10-mg oral dose to the elderly. By contrast, peak plasma levels of 2.10, 0.85, 1.06, and 2.71 ng/mL were observed for SEL, DMS, AMP, and MET after a single 24-h application of 1 STS. Comparison of dose-corrected areas under the curve (AUCs) (made under the assumption of linear pharmacokinetics) indicate the SEL exposure after transdermal application was more than 50-fold greater than that obtained orally. This increase in systemic SEL exposure at the expense of metabolite formation that is reduced to <70% of that obtained orally for N-DMS, L-AMP, and L-MET is hypothesized to be of therapeutic value in patients with a variety of neurodegenerative and psychiatric disorders.  相似文献   
69.

Purpose

We evaluated the use of renal ultrasound for monitoring pyelocaliectasis after pyeloplasty in children.

Materials and Methods

Changes in pyelocaliceal dilatation following pyeloplasty were assessed by serial ultrasound. Of 104 children 0 to 12 years old who underwent pyeloplasty between 1982 and 1992, 44 (47 renal units) were monitored with serial ultrasound for at least 2 years (range 2 to 9, mean 3.8). Patient ages at pyeloplasty were 0 to 3 months (17), 4 to 12 months (8), 1 to 6 years (13) and 7 to 12 years (6). Preoperative and postoperative ultrasound was reviewed by a single pediatric radiologist blinded to the date of surgery. The degree of pyelocaliectasis was graded as 0 to 4 according to the classification of the Society for Fetal Urology.

Results

Preoperative ultrasound revealed grade 4 pyelocaliectasis in 26 kidneys (55 percent) and grade 3 disease in 21 (45 percent). Grade was the same or worse 1 month after pyeloplasty in the majority of kidneys (92 percent) studied at this interval. Of the 47 renal units assessed 43 (91 percent) showed improvement in pyelocaliectasis during postoperative followup. Only 38 percent of the kidneys improved during the first 6 months of followup, while 81 percent were improved 2 years postoperatively. Improvement to grade 0 or 1 dilatation occurred in only 9 kidneys (19 percent). The rate of resolution of pyelocaliectasis was not related to preoperative grade or patient age at pyeloplasty.

Conclusions

Improvement on renal ultrasound after pyeloplasty appears to be gradual. Less than half of the patients had improvement in the initial 6 months after pyeloplasty and pyelocaliectasis rarely resolved completely. While renal ultrasound can provide an accurate and cost-effective means of monitoring children on a long-term basis after pyeloplasty, sonographic evaluation in the early postoperative period commonly shows increased or unchanged pyelocaliectasis.  相似文献   
70.
We report three patients who developed severe supraglottic airway obstruction due to Epstein-Barr virus lymphoproliferative disease following allogeneic bone marrow transplantation. In addition to enlarged pharyngeal lymphoid tissue seen in all three patients, two had supraglottic airway narrowing and two developed pulmonary lymphoproliferative disease. They were treated with unmanipulated T cells or EBV-specific cytotoxic T lymphocytes. Life-threatening upper airway obstruction is a radiologically detectable complication of allogeneic bone marrow transplantation in children. Received: 12 August 1997 Accepted: 11 December 1997  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