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   3257篇
  免费   269篇
  国内免费   31篇
耳鼻咽喉   68篇
儿科学   137篇
妇产科学   51篇
基础医学   365篇
口腔科学   93篇
临床医学   482篇
内科学   529篇
皮肤病学   42篇
神经病学   201篇
特种医学   266篇
外科学   595篇
综合类   78篇
预防医学   207篇
眼科学   53篇
药学   206篇
中国医学   3篇
肿瘤学   181篇
  2022年   18篇
  2021年   33篇
  2020年   36篇
  2019年   39篇
  2018年   40篇
  2017年   47篇
  2016年   57篇
  2015年   54篇
  2014年   83篇
  2013年   107篇
  2012年   128篇
  2011年   143篇
  2010年   119篇
  2009年   121篇
  2008年   193篇
  2007年   179篇
  2006年   180篇
  2005年   166篇
  2004年   159篇
  2003年   149篇
  2002年   135篇
  2001年   57篇
  2000年   44篇
  1999年   53篇
  1998年   69篇
  1997年   71篇
  1996年   58篇
  1995年   55篇
  1994年   43篇
  1993年   47篇
  1992年   48篇
  1991年   40篇
  1990年   42篇
  1989年   46篇
  1988年   54篇
  1987年   76篇
  1986年   52篇
  1985年   41篇
  1984年   33篇
  1983年   26篇
  1982年   45篇
  1981年   37篇
  1980年   29篇
  1979年   24篇
  1978年   26篇
  1977年   28篇
  1976年   34篇
  1975年   20篇
  1974年   18篇
  1966年   14篇
排序方式: 共有3557条查询结果,搜索用时 15 毫秒
31.
We report a case of fetal microphthalmia diagnosed midtrimester by ultrasound and fetal MRI. Included is a comparison of MRI measurements of normal fetuses at similar gestational age and a review of the literature.  相似文献   
32.
33.
34.
Biopsy specimens of clinically normal skin of 9 consecutive patients with SLE were examined ultrastructurally to determine the presence and frequency of microtubular inclusions. Ten blood vessels were examined in each specimen; every specimen contained at least two positive blood vessels, and some contained 80 to 100% positive vessels. No correlation was found between the frequency of the inclusions and either the disease duration or antinuclear factor titer. The inclusions tended to be more frequent in patients with more acute disease. The absence of inclusions in normal skin may mitigate a diagnosis of SLE.  相似文献   
35.
An attributional analysis of ECT as a placebo was investigated by comparing the attitudes of patients on two psychiatric wards. It was hypothesized that on the ward on which ECT was administered more frequently, general attitudes toward the treatment would be more favorable and more patients would express the opinion that ECT had worked well for them personally. The results, which supported the predictions, indicate that the operation of placebo effects in connection with ECT may account for differential treatment results more adequately than explanations based on physiological models. The findings also suggest that more research is needed to explore the relationship between patients' attitudes and treatment outcomes.  相似文献   
36.
The widely used alkylating agent cyclophosphamide (CY) has substantive interpatient variability in the area under the curve (AUC) of it and its metabolites. Numerous factors may influence the drug‐metabolizing enzymes that metabolize CY to 4‐hydroxycyclophosphamide (4HCY), the principal precursor to CY’s cytotoxic metabolite. We sought to identify endogenous metabolomics compounds (EMCs) associated with 4HCY formation clearance (ratio of 4HCY/CY AUC) using global metabolomics. Patients who undergo hematopoietic cell transplantation receiving post‐transplant CY (PT‐CY) were enrolled, cohort 1 (n = 26) and cohort 2 (n = 25) donating longitudinal blood samples before they started HCT (pre‐HCT), before infusion of the donor allograft (pre‐graft), before the first dose of PT‐CY (pre‐CY), and 24 h after the first dose of PT‐CY (24‐h post‐CY), which is also immediately before the second dose of CY. A total of 512 and 498 EMCs were quantitated in two cohorts, respectively. Both univariate linear regression with false discovery rate (FDR), and pathway enrichment analyses using a global association test were performed. At the pre‐CY time point, no EMCs were associated at FDR less than 0.1. At pre‐HCT, cohort 1 had one EMC (levoglucosan) survive the FDR threshold. At pre‐graft, cohort 1 and cohort 2 had 20 and 13 EMCs, respectively, exhibiting unadjusted p values less than 0.05, with the only EMCs having an FDR less than 0.1 being two unknown EMCs. At 24‐h post‐CY, there were three EMCs, two ketones, and threitol, at FDR less than 0.1 in cohort 2. These results demonstrate the potential of pharmacometabonomics, but future studies in larger samples are needed to optimize CY.

Study Highlights
  • WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?
We report the first pharmacometabonomic study of the association of plasma EMCs with cyclophosphamide pharmacokinetics, specifically the ratio of 4HCY/CY AUC.
  • WHAT QUESTION DID THIS STUDY ADDRESS?
This study addresses the question regarding if EMCs in the plasma before PT‐CY administration are associated with the ratio of 4HCY/CY AUC.
  • WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?
This study adds to our knowledge that longitudinal collection of plasma EMC samples is feasible in HCT patients receiving PT‐CY. In addition, the plasma EMC changes over the ~21‐day time period that starts pre‐HCT to 24‐hr after the first PT‐CY dose.
  • HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?
This study demonstrates the possibility of pharmacometabolomic research to evaluate the pharmacokinetics of a drug – in this case, cyclophosphamide – with a complex pharmacokinetic disposition.  相似文献   
37.
38.
39.
40.
End-stage periventricular leukomalacia: MR evaluation   总被引:3,自引:0,他引:3  
Baker  LL; Stevenson  DK; Enzmann  DR 《Radiology》1988,168(3):809-815
A prospective study was performed to assess the capabilities of magnetic resonance (MR) imaging in evaluation of end-stage periventricular leukomalacia (PVL) in six children, aged 31-54 months, in whom PVL had been documented by neurologic ultrasonography during the neonatal period. Eight children of similar age (four premature infants and four full-term infants) with normal neurologic development served as controls. A characteristic triad of PVL abnormalities was seen on MR images: (a) abnormally increased periventricular white-matter signal intensity on the first and second echo images of a T2-weighted sequence (repetition time = 2,000-2,400 msec, echo times = 20 or 30 and 80 msec), most commonly observed in the trigone regions of the lateral ventricles bilaterally; (b) marked loss of periventricular white matter in these regions of abnormal signal intensity, predominantly in the periatrial regions; and (c) compensatory focal ventricular enlargement adjacent to regions of abnormal signal intensity. In patients with the classic periatrial distribution of PVL lesions, general correlation between the degree of neurologic impairment and the severity of MR abnormalities was demonstrated. MR imaging was useful in detecting subtle forms of PVL in cases in which neurologic damage was subclinical.  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