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   631篇
  免费   89篇
  国内免费   4篇
耳鼻咽喉   1篇
儿科学   49篇
妇产科学   12篇
基础医学   91篇
口腔科学   31篇
临床医学   120篇
内科学   140篇
皮肤病学   15篇
神经病学   30篇
特种医学   39篇
外科学   30篇
综合类   15篇
预防医学   67篇
眼科学   11篇
药学   28篇
肿瘤学   45篇
  2024年   2篇
  2023年   11篇
  2021年   12篇
  2020年   7篇
  2019年   11篇
  2018年   27篇
  2017年   14篇
  2016年   11篇
  2015年   17篇
  2014年   31篇
  2013年   35篇
  2012年   16篇
  2011年   23篇
  2010年   27篇
  2009年   41篇
  2008年   29篇
  2007年   20篇
  2006年   19篇
  2005年   22篇
  2004年   18篇
  2003年   9篇
  2002年   10篇
  2001年   7篇
  2000年   12篇
  1999年   17篇
  1998年   22篇
  1997年   33篇
  1996年   37篇
  1995年   27篇
  1994年   21篇
  1993年   18篇
  1992年   3篇
  1991年   4篇
  1990年   7篇
  1989年   16篇
  1988年   8篇
  1987年   6篇
  1986年   11篇
  1985年   10篇
  1984年   8篇
  1983年   6篇
  1982年   10篇
  1981年   6篇
  1980年   11篇
  1978年   4篇
  1977年   3篇
  1976年   4篇
  1970年   1篇
排序方式: 共有724条查询结果,搜索用时 203 毫秒
61.
Swett  HA; Fisher  PR; Cohn  AI; Miller  PL; Mutalik  PG 《Radiology》1989,172(2):487-493
Conventional computer-based medical expert systems deliver advice to physicians as written text. While such advice is useful, it has distinct limitations in a visually oriented discipline such as diagnostic radiology, in which decisions often depend on pattern recognition and appreciation of subtle morphologic features. The authors developed a prototype expert computer system, IMAGE/ICON, which displays groups of images sorted into a series of axes based on different ways in which they may be similar. They may share a common feature, group of features, causes, or clinical setting. IMAGE/ICON may display examples of morphologic variations of a dominant finding or a spectrum of abnormalities seen in an specific disease or group of diseases. The system also assembles a written analysis of key features of a case. Such a tool may be useful as a diagnostic aid or for continuing medical education. It is likely to have particular impact in the form of an intelligent radiologic workstation, as picture archiving and communication systems become available.  相似文献   
62.
This prospective study investigated the role of reduced hepatic synthesis of regulating proteins in coagulopathy after partial hepatectomy (PH) compared with major abdominal surgery (MAS) without involvement of the liver. Furthermore, we studied the effect of rBPI21, an endotoxin-neutralizing agent, on coagulopathy after PH was studied. Compared with MAS, PH resulted in significantly elevated levels of thrombin-antithrombin-III and plasmin-alpha2-antiplasmin complexes. Levels of antithrombin-3, alpha2-antiplasmin, fibrinogen, plasminogen, alpha2-macroglobulin (alpha2-M), and C1-inhibitor remained lower following PH. Treatment with rBPI21 led to significantly lower levels of tissue-type plasminogen activator (t-PA). Post-operative disseminated intravascular coagulation (DIC) was associated with significantly higher bilirubin and t-PA plasma levels and significantly lower levels of alpha2-M. This study indicates that PH induced hepatic failure results in decreased synthesis of hepatic regulating plasma proteins and subsequent activation of coagulation and fibrinolysis. Prevention of t-PA release by rBPI21 may have important clinical implications. Decreased availability of alpha2-M may be a factor in post-operative DIC.  相似文献   
63.
The population structure of Staphylococcus aureus carried by healthy humans was determined using a large strain collection of nonclinical origin (n = 829). High-throughput amplified fragment length polymorphism (AFLP) analysis revealed 3 major and 2 minor genetic clusters of S. aureus, which were corroborated by multilocus sequence typing. Major AFLP cluster I comprised 44.4% of the carriage isolates and showed additional heterogeneity whereas major AFLP groups II and III presented 2 homogeneous clusters, including 47.3% of all carriage isolates. Coanalysis of invasive S. aureus strains and epidemic methicillin-resistant S. aureus (MRSA) revealed that all major clusters contained invasive and multiresistant isolates. However, clusters and subclusters with overrepresentation of invasive isolates were also identified. Bacteremia in elderly adults, for instance, was caused by a IVa cluster-derived strain significantly more often than by strains from other AFLP clusters. Furthermore, expansion of multiresistant clones or clones associated with skin disease (impetigo) was detected, which suggests that epidemic potential is present in pathogenic strains of S. aureus. In addition, the virulence gene encoding Panton-Valentine leukocidin was significantly enriched in S. aureus strains causing abscesses and arthritis in comparison with the carriage group. We provide evidence that essentially any S. aureus genotype carried by humans can transform into a life-threatening human pathogen but that certain clones are more virulent than others.  相似文献   
64.
In hereditary cerebral hemorrhage with amyloidosis of the Dutch type (HCHWA-D), severe cerebral amyloid angiopathy (CAA) is associated with an inflammatory reaction. Small heat shock proteins (sHsps) are molecular chaperones and association of HspB8 with CAA in HCHWA-D has been observed. The aims of this study were to investigate (1) if other sHsps are associated with the pathological lesions in HCHWA-D brains, (2) if the amyloid-beta protein (A beta) increases production of sHsps in cultured cerebral cells and (3) if sHsps are involved in the cerebral inflammatory processes in both Alzheimer's disease (AD) and HCHWA-D. We conclude that Hsp20, HspB8 and HspB2 are present in CAA in HCHWA-D, and that A beta did not affect cellular sHsps expression in cultured human brain pericytes and astrocytes. In addition, we demonstrated that Hsp20, HspB2 and HspB8 induced interleukin-6 production in cultured pericytes and astrocytes, which could be antagonized by dexamethasone, whereas other sHsps and A beta were inactive, suggesting that sHsps may be among the key mediators of the local inflammatory response associated with HCHWA-D and AD lesions.  相似文献   
65.

Background and purpose:

The function of transporters in peripheral blood mononuclear cells (PBMC) has been characterized, but less is known about cytochrome P450 (CYP) enzyme function in these cells. Given that cytokines are dysregulated in many diseases, the purpose of this work was to assess the impact of cytokines on the expression of CYPs, transporters and chemokine receptors in PBMC.

Experimental approach:

Human PBMC were incubated with cytokines for 48 h. ATP-binding cassette (ABC)B1, ABCC1, ABCC2, CYP2B6, CYP3A4, CXCR4 and CCR5 expression were measured by quantitative polymerase chain reaction and flow cytometry at 0, 4, 8, 24 and 48 h. Enzyme activity was assessed using fluorescent probes.

Key results:

We show here functional activity of CYP3A4 and CYP2B6 in PBMC. Furthermore, cytokines had a significant impact on the mRNA and protein expression of all proteins. For example, interleukin-2 (IL-2) had a marked impact on ABCB1 mRNA (% control 4745 ± 11961) and protein (% control 200 ± 57). Increases in drug efflux transporter expression, in response to cytokines, resulted in reduced cellular accumulation of digoxin [decrease of 17% and 26% for IL-2 and interferon-γ (IFNγ) respectively] and saquinavir (decrease of 28% and 30% for IL-2 and IFNγ respectively). The degree to which drug transporter and chemokine receptor expression changed in response to cytokines was positively correlated (e.g. ABCB1 and CXCR4, r2 = 0.545).

Conclusions and implications:

These data have important implications for diseases in which cytokines are dysregulated and for which pharmacological intervention targets immune cells.  相似文献   
66.

Introduction

Seven SNPs in five genomic loci were recently found to confer a mildly increased risk of breast cancer.

Methods

We have investigated the correlations between disease characteristics and the patient genotypes of these SNPs in an unselected prospective cohort of 1,267 consecutive patients with primary breast cancer.

Results

Heterozygote carriers and minor allele homozygote carriers for SNP rs889312 in the MAP3K1 gene were less likely to be lymph node positive at breast cancer diagnosis (P = 0.044) relative to major allele homozygote carriers. Heterozygote carriers and minor allele homozygote carriers for SNP rs3803662 near the TNCR9 gene were more likely to be diagnosed before the age of 60 years (P = 0.025) relative to major allele homozygote carriers. We also noted a correlation between the number of minor alleles of rs2981582 in FGFR2 and the average number of first-degree and second-degree relatives with breast cancer and/or ovarian cancer (P = 0.05). All other disease characteristics, including tumour size and grade, and oestrogen or progesterone receptor status, were not significantly associated with any of these variants.

Conclusion

Some recently discovered genomic variants associated with a mildly increased risk of breast cancer are also associated with breast cancer characteristics or family history of breast cancer and ovarian cancer. These findings provide interesting new clues for further research on these low-risk susceptibility alleles.  相似文献   
67.

Background

People affected by kidney failure receiving haemodialysis experience complexity within their health condition unlike any other chronic illness or condition. Kidney failure impacts the individual in all areas of their life including relationships and activities of daily living.

Objective

To conduct a meta-aggregation of studies about the lived experiences of people with kidney failure receiving haemodialysis.

Design

Using PRISMA Guidelines, six databases (CINAHL, ClinicalTrials.gov , Cochrane Library, MEDLINE, PsycINFO, and Scopus) were comprehensively searched using keywords and subject headings from January 1990 to October 2021. Articles were assessed according to prespecified eligibility criteria. Data extraction and quality appraisal was conducted. A meta-aggregation of qualitative findings was conducted using the Joanna Briggs Institute methodology for meta-aggregation.

Results

Of the 9409 articles screened, 55 studies were included. This represented a total of 188 findings across 45 categories representing a range of unmet supportive care needs. The meta-aggregation identified 11 synthesised findings broadly related to psychological/emotional needs, physical needs, social needs, interpersonal/intimacy needs, patient-clinician communication needs, family related needs, health system/information needs, spiritual needs, daily living needs, practical needs and daily living needs.

Conclusions

This meta-aggregation has identified that people affected by kidney failure can experience a range of unmet supportive care needs. It was evident that living with kidney failure and receiving haemodialysis impacted a person's sense of self, introduced practical needs and other complex needs which were not being addressed in existing services. This review has highlighted important implications for clinical practice and future research directions.  相似文献   
68.
Over the last 30 years there has been a considerable increase in the life expectancy of people with learning disabilities. This has resulted in changing patterns of morbidity and mortality and an increasing recognition of the health needs of people with learning disabilities. Major strides forward have been made in the reduction of preventable illnesses among the general population. However, among people with learning disabilities such illnesses have received only limited health promotion attention until recently. In the last decade major gaps have been identified in the ability of current primary health services to respond to the needs of people with learning disabilities. The need to respond effectively to this situation has been identified as a priority by the current United Kingdom Government. Following an overview of the literature in relation to the changing health profile of people with learning disabilities and the need for health screening, consideration is given to some of the key difficulties which may be encountered when attempting to utilize current primary health services. The analysis of data derived from the health screening of 373 people with learning disabilities by a community nursing service in Down and Lisburn Health and Social Services Trust reveals the need for further action in relation to cardiovascular status, sensory deficits, mobility and aspects of sexual health.  相似文献   
69.
70.
This paper examines the effectiveness of current strategies for health promotion in the UK in the light of knowledge about the links between health, illness and poverty. The implications of recent policies which target health promotion within primary health care (PHC) settings are examined. The results of an exploratory study undertaken during 1993/94 in a city in South West England are discussed. This qualitative study used semi-structured interviews to investigate the perceptions of a range of PHC professionals. Fifty-four interviews were carried out amongst staff in 16 PHC practices. This paper reports on professionals' views and practice in relation to promoting health in areas of poverty and with low-income clients. These findings are discussed in relation to the literature and the constraints on effective health promotion in PHC are explored particularly in relation to issues of poverty and deprivation.  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