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   1781篇
  免费   116篇
  国内免费   5篇
耳鼻咽喉   20篇
儿科学   47篇
妇产科学   80篇
基础医学   233篇
口腔科学   7篇
临床医学   284篇
内科学   258篇
皮肤病学   15篇
神经病学   191篇
特种医学   35篇
外科学   188篇
综合类   23篇
一般理论   2篇
预防医学   283篇
眼科学   9篇
药学   103篇
中国医学   1篇
肿瘤学   123篇
  2023年   13篇
  2022年   34篇
  2021年   69篇
  2020年   30篇
  2019年   51篇
  2018年   67篇
  2017年   45篇
  2016年   47篇
  2015年   49篇
  2014年   78篇
  2013年   92篇
  2012年   174篇
  2011年   156篇
  2010年   96篇
  2009年   57篇
  2008年   93篇
  2007年   118篇
  2006年   86篇
  2005年   123篇
  2004年   88篇
  2003年   93篇
  2002年   68篇
  2001年   12篇
  2000年   9篇
  1999年   10篇
  1998年   16篇
  1997年   7篇
  1996年   9篇
  1995年   11篇
  1994年   11篇
  1993年   13篇
  1992年   8篇
  1991年   4篇
  1990年   4篇
  1988年   6篇
  1984年   2篇
  1983年   6篇
  1981年   3篇
  1978年   2篇
  1976年   3篇
  1975年   2篇
  1974年   2篇
  1972年   3篇
  1971年   2篇
  1970年   4篇
  1969年   2篇
  1968年   2篇
  1967年   2篇
  1961年   2篇
  1926年   2篇
排序方式: 共有1902条查询结果,搜索用时 390 毫秒
41.
Abstract

This paper presents the case of JAS, a developmental dyslexic who had largely resolved her reading problems as an undergraduate student. However, testing revealed that JAS had subtle reading deficits, having difficulty with low-frequency irregular words and with the comprehension of written homophones. In contrast, her phonological reading strategies were normal. JAS's reading deficit was accompanied by serious spelling problems; she showed a marked tendency to spell phonologically, although with reference to some word-specific knowledge.

JAS's reading and spelling difficulties were accompanied by significant visual memory deficits although phonological processing was relatively good. It is argued that visual memory impairments have prevented JAS from establishing detailed orthographic representations in a lexical system. In the absence of these, the operation of the system for reading is faulty; for spelling, which requires die use of full orthographic cues, there are serious consequences.  相似文献   
42.
Sport Sciences for Health - Camogie is one of the most popular female sports in Ireland, yet the demands of match-play are unknown. The current study aimed to examine the match-play running...  相似文献   
43.
44.
45.
Background/Study Context: While most aging research on memory uses a retention interval of one hour or less, episodic consolidation takes longer (e.g., 6–24 hours for synaptic consolidation). In three experiments, we examined age differences in recall followed by recognition in which the retention interval was varied in younger and older adults.

Methods: In Experiment 1 (n = 24 for both age groups), zero-, 1- and 24-hour retention intervals were used for recall for all participants, and a 24-hour retention interval was used for recognition. In Experiment 2 (n = 24 for both age groups), just a 24-hour retention interval was used. In Experiment 3 (n = 20 for both age groups), a within-subjects design was used in which participants recalled one word list after one hour and again after 24 hours, and recalled another word list just after 24 hours (with recognition for both conditions after the 24-hour recall).

Results: In Experiment 1, older adults recalled fewer words at both the 1- and 24-hour retention intervals, but the magnitude of the age difference did not differ. In Experiment 2 (just 24-hour retention interval), there were no age differences in recall. In Experiment 3, in the two-recall condition, older adults showed lower recall at both 1-hour and 24-hour retention intervals (but the magnitude of the age difference remained constant across retention interval). In the single-recall just 24-hour retention condition, there were no age differences. There were no age differences in recognition in any of the three experiments.

Conclusion: These results suggest that recall declines for a 24-hour retention interval relative to a zero or one-hour retention interval (Experiments 1 and 3) for both age groups. However, when the first recall attempt occurs after a 24-hour retention interval, there are no age differences. These replicated results suggest that older adults do not benefit as much as younger adults from pre-consolidated rehearsal, but that rehearsal-based age differences do not increase in magnitude from the last rehearsal to memory consolidation. Furthermore, (along with), the present results indicate that there are no age differences in recall when the first recall attempt occurs after a long retention interval – when memory consolidation is likely to have occurred before the first retrieval attempt.  相似文献   

46.
BACKGROUND: Post-kala-azar dermal leishmaniasis (PKDL), an established sequela of visceral leishmaniasis (VL), is proposed to facilitate anthroponotic transmission of VL, especially during interepidemic periods. Immunopathological mechanisms responsible for Indian PKDL are still poorly defined. METHODS: Our study attempted to characterize the immune profiles of patients with PKDL or VL relative to that of healthy control subjects by immunophenotyping, intracellular cytokine staining of peripheral blood mononuclear cells, and enzyme-linked immunosorbent assay for serum cytokines and immunoglobulin G (IgG) subclasses. RESULTS: Patients with PKDL had significantly raised percentages of peripheral CD3+CD8+ cells compared with control subjects, a difference that persisted after cure. Patients with PKDL showed an intact response to phytohemagglutinin, with the percentages of lymphocytes expressing interferon (IFN)-gamma, interleukin (IL)-2, IL-4, and IL-10 being comparable to those in control subjects. Patients with VL had decreased IFN-gamma and IL-2 expression, which was restored after cure, and increased IL-10 expression, which persisted after cure. In their response to Leishmania donovani antigen, patients with PKDL showed a 9.6-fold increase in the percentage of IL-10-expressing CD3+CD8+ lymphocytes compared with control subjects, and this percentage decreased with treatment. Patients with PKDL had raised levels of IgG3 and IgG1 (surrogate markers for IL-10), concomitant with increased serum levels of IL-10. CONCLUSIONS: IL-10-producing CD3+CD8+ lymphocytes are important protagonists in the immunopathogenesis of Indian PKDL.  相似文献   
47.
Background: The impact of a low-glucose peritoneal dialysis (PD) regimen on biomarkers of peritoneal inflammation, fibrosis and membrane integrity remains to be investigated.♦ Methods: In a randomized, prospective study, 80 incident PD patients received either a low-glucose regimen comprising Physioneal (P), Extraneal (E) and Nutrineal (N) (Baxter Healthcare Corporation, Deerfield, IL, USA) (PEN group), or Dianeal (control group) for 12 months, after which both groups continued with Dianeal dialysis for 6 months. Serum and dialysate levels of vascular endothelial growth factor (VEGF), decorin, hepatocyte growth factor (HGF), interleukin-6 (IL-6), macrophage migration inhibitory factor (MIF), hyaluronan (HA), adiponectin, soluble-intracellular adhesion molecule (s-ICAM), vascular cell adhesion molecule-1 (VCAM-1) and P-selectin, and dialysate cancer antigen 125 (CA125), were measured after 12 and 18 months. This paper focuses on results after 12 months, when patients in the PEN group changed to glucose-based PD fluid (PDF).♦ Results: At the end of 12 months, effluent dialysate levels of CA125, decorin, HGF, IL-6, adiponectin and adhesion molecules were significantly higher in the PEN group compared to controls, but all decreased after patients switched to glucose-based PDF. Macrophage migration inhibitory factor level was lower in the PEN group but increased after changing to glucose-based PDF and was similar to controls at 18 months. Serum adiponectin level was higher in the PEN group at 12 months, but was similar in the 2 groups at 18 months. Body weight, residual renal function, ultrafiltration volume and total Kt/V did not differ between both groups. Dialysate-to-plasma creatinine ratio at 4 h was higher in the PEN group at 12 months and remained so after switching to glucose-based PDF.♦ Conclusion: Changes in the biomarkers suggest that the PEN PD regimen may be associated with better preservation of peritoneal membrane integrity and reduced systemic vascular endothelial injury.  相似文献   
48.
Myeloma is one of the most common malignancies that results in osteolytic lesions of the spine. Complications, including pathological fractures of the vertebrae and spinal cord compression, may cause severe pain, deformity and neurological sequelae. They may also have significant consequences for quality of life and prognosis for patients. For patients with known or newly diagnosed myeloma presenting with persistent back or radicular pain/weakness, early diagnosis of spinal myeloma disease is therefore essential to treat and prevent further deterioration. Magnetic resonance imaging is the initial imaging modality of choice for the evaluation of spinal disease. Treatment of the underlying malignancy with systemic chemotherapy together with supportive bisphosphonate treatment reduces further vertebral damage. Additional interventions such as cement augmentation, radiotherapy, or surgery are often necessary to prevent, treat and control spinal complications. However, optimal management is dependent on the individual nature of the spinal involvement and requires careful assessment and appropriate intervention throughout. This article reviews the treatment and management options for spinal myeloma disease and highlights the value of defined pathways to enable the proper management of patients affected by it.  相似文献   
49.

Background and objectives

Presumed genetic risk for diabetic and nondiabetic end stage renal disease is strong in African Americans.

Design, setting, participants, & measurements

Exome sequencing data from African Americans with type 2 diabetic end stage renal disease and nondiabetic, non-nephropathy controls in the T2D-GENES study (Discovery, n=529 patients and n=535 controls) were evaluated, focusing on missense variants in NPHS1. Associated variants were then evaluated in independent type 2 diabetic end stage renal disease (Replication, n=1305 patients and n=760 controls), nondiabetic end stage renal disease (n=1705), and type 2 diabetes-only, non-nephropathy samples (n=503). All participants were recruited from dialysis facilities and internal medicine clinics across the southeastern United States from 1991 to present. Additional NPHS1 missense variants were identified from exome sequencing resources, genotyped, and sequence kernel association testing was then performed.

Results

Initial analysis identified rs35238405 (T233A; minor allele frequency=0.0096) as associated with type 2 diabetic end stage renal disease (adjustment for admixture P=0.042; adjustment for admixture+APOL1 P=0.080; odds ratio, 2.89 and 2.36, respectively); with replication in independent type 2 diabetic end stage renal disease samples (P=0.018; odds ratio, 4.30) and nondiabetic end stage renal disease samples (P=0.016; odds ratio, 4.48). In a combined analysis (all patients with end stage renal disease versus all controls), T233A was associated with all-cause end stage renal disease (P=0.0038; odds ratio, 2.82; n=3270 patients and n=1187 controls). A P-value of <0.001 was obtained after adjustment for admixture and APOL1 in sequence kernel association testing. Two additional variants (H800R and Y1174H) were nominally associated with protection from end stage renal disease (P=0.036; odds ratio, 0.44; P=0.0084; odds ratio, 0.040, respectively) in the locus-wide single-variant association tests.

Conclusions

Coding variants in NPHS1 are associated with both risk for and protection from common forms of nephropathy in African Americans.  相似文献   
50.
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