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   8302篇
  免费   511篇
  国内免费   150篇
耳鼻咽喉   65篇
儿科学   208篇
妇产科学   360篇
基础医学   943篇
口腔科学   118篇
临床医学   965篇
内科学   1941篇
皮肤病学   107篇
神经病学   565篇
特种医学   660篇
外科学   998篇
综合类   151篇
一般理论   3篇
预防医学   414篇
眼科学   180篇
药学   588篇
中国医学   46篇
肿瘤学   651篇
  2023年   50篇
  2022年   82篇
  2021年   193篇
  2020年   95篇
  2019年   163篇
  2018年   213篇
  2017年   150篇
  2016年   128篇
  2015年   239篇
  2014年   301篇
  2013年   389篇
  2012年   582篇
  2011年   532篇
  2010年   332篇
  2009年   369篇
  2008年   466篇
  2007年   428篇
  2006年   398篇
  2005年   415篇
  2004年   365篇
  2003年   299篇
  2002年   246篇
  2001年   234篇
  2000年   203篇
  1999年   197篇
  1998年   139篇
  1997年   107篇
  1996年   97篇
  1995年   95篇
  1994年   74篇
  1993年   64篇
  1992年   127篇
  1991年   91篇
  1990年   101篇
  1989年   91篇
  1988年   104篇
  1987年   97篇
  1986年   84篇
  1985年   86篇
  1984年   83篇
  1983年   42篇
  1982年   40篇
  1981年   24篇
  1980年   27篇
  1979年   42篇
  1978年   32篇
  1977年   39篇
  1976年   30篇
  1975年   46篇
  1974年   23篇
排序方式: 共有8963条查询结果,搜索用时 20 毫秒
991.
Objectives. We investigated whether reported experience of racial discrimination in health care and in other domains was associated with cancer screening and negative health care experiences.Methods. We used 2006/07 New Zealand Health Survey data (n = 12 488 adults). We used logistic regression to examine the relationship of reported experience of racial discrimination in health care (unfair treatment by a health professional) and in other domains (personal attack, unfair treatment in work and when gaining housing) to breast and cervical cancer screening and negative patient experiences adjusted for other variables.Results. Racial discrimination by a health professional was associated with lower odds of breast (odds ratio [OR] = 0.37; 95% confidence interval [CI] = 0.14, 0.996) and cervical cancer (OR = 0.51; 95% CI = 0.30, 0.87) screening among Maori women. Racial discrimination by a health professional (OR = 1.57; 95% CI = 1.15, 2.14) and racial discrimination more widely (OR = 1.55; 95% CI = 1.35, 1.79) were associated with negative patient experiences for all participants.Conclusions. Experience of racial discrimination in both health care and other settings may influence health care use and experiences of care and is a potential pathway to poor health.Racism is increasingly recognized as an important determinant of health and driver of ethnic health inequalities.1 Regardless of its health effects, racism breaches fundamental human rights and is morally wrong. It is important to understand how racism operates as a health risk to develop interventions that reduce ethnic inequalities in health within a context of eliminating racism.2Racism is an organized system that categorizes racial/ethnic groups and structures opportunity, leading to inequities in societal goods and resources and a racialized social order.3–5 Racism operates via institutional and individual practices (racial discrimination) and varies in form and type.6,7 The pathways whereby racism leads to poor health are also multiple, with direct and indirect mechanisms such as race-based assaults and violence, physiological and psychological stress mechanisms, differential exposures to health risk factors, differential access to and experiences of health care, and differential access to goods, resources, and power in society.6,8–10Research on racism and health, particularly self-reported racism, has increased. Self-reported experience of racism has been linked to multiple health measures (including mental and physical health outcomes and health risk factors) across a variety of countries and for different ethnic groups.10–12 Research on how self-reported experience of racism may negatively affect health has largely focused on racism as a stressor with mental and physical health consequences.10,13 Comparatively less evidence is available on how experience of racism may influence health service use,10 although this is another potentially important pathway to poor health.14,15Studies on the association between self-reported racism and health care experience and use have included racism experienced within the health care system, outside of the health care system, or both.16–19 Health care measures have included use of specific services such as cancer screening19–24 and receipt of optimal care,20,25 measures of unmet need,16,26 measures of adherence to care,17,27,28 and measures of satisfaction and experiences with care.18,29–31Various mechanisms have been suggested to explain how the experience of racism may negatively affect health care use, experiences of health care, and subsequent poor health. Experiences of racism within the health care system may influence health by shaping decision making of both providers and patients and influencing future health behaviors, including future health care use behaviors and potential disengagement from the health care system.14,18,26 Experiences of racism in wider society also may lead to general mistrust and avoidance of dominant culture institutions, including health care systems.15,30 This is supported by evidence that both experiences of racism and general discrimination within and outside of health care have been associated with negative health care use measures.15,16,19,22New Zealand has a population of approximately 4.4 million people, with the major ethnic groupings being Maori (indigenous peoples, 15% of the population), European (77%), Pacific (7%), and Asian (10%).32 Ethnic inequalities in health and socioeconomic status persist, with racism a potentially important contributor to these inequalities.33 Previous research in New Zealand has shown reported experience of racial discrimination by a health professional to be higher among non-European ethnic groups with experiences of racial discrimination in different settings associated with multiple health outcomes and risk factors.34In this study, we focused on the relationship between racial discrimination and health service use and experience, an area not previously examined in New Zealand. We provide important information on how racial discrimination may affect health care use as a possible pathway to poor health outcomes and ethnic health inequalities in New Zealand. In addition, our study contributes to the limited evidence on racial discrimination and health care internationally.Primary health care in New Zealand is available to all residents and is usually provided at general practices. Costs of visits are universally subsidized by government to enable lower patient copayments with additional limited provision for extra funding based on high need.35 Currently, 2 publicly funded national cancer screening programs are available.36 Breast cancer screening is free to all eligible women through BreastScreen Aotearoa. Cervical cancer screening usually incurs a fee and is available through patients’ usual primary care provider or specific cervical cancer screening providers.We specifically examined the association between self-reported experience of racial discrimination and the use of health care in 2 domains—cancer screening and negative patient perceptions of health care encounters. We hypothesized that experience of racial discrimination both within and outside the health care system may negatively affect how individuals use and experience health care.  相似文献   
992.
Self-reported experience of racial discrimination has been linked to a range of health outcomes in various countries and for different ethnic groups. This study builds on previous work in New Zealand to further investigate the prevalence of self-reported experience of racial discrimination by ethnicity, changes over time and associations with multiple health measures. The study uses data from the 2002/03 (n=12,500) and 2006/07 (n=12,488) New Zealand Health Surveys, nationally representative population-based surveys of adults (15+ years). Reported experience of racial discrimination was measured in both surveys and covered 5 items: experience of an ethnically motivated physical or verbal attack; and unfair treatment because of ethnicity by a health professional, in work, or when gaining housing. Ethnicity was classified as Maori, Pacific, Asian or European. Health indicators included measures of: mental health (SF36 mental health scale, psychological distress, doctor diagnosed mental health condition); physical health (self-rated health, SF36 physical functioning scale, cardiovascular disease); and health risk (smoking, hazardous drinking, excess body fat). Logistic regression was used to examine changes in prevalence of reported experience of racial discrimination over time and associations with health. Reported experience of racial discrimination increased between 2002/03 (28.1% ever) and 2006/07 (35.0% ever) among Asian peoples but remained largely unchanged for other ethnic groupings (Maori 29.5%, Pacific 23.0%, European 13.5%). Experience of racial discrimination was associated with all negative health measures except excess body fat. Where there were significant associations, a dose-response relationship was also evident. We conclude that racial discrimination experienced across a range of settings has the potential to impact on a wide range of health outcomes and risk factors. While ongoing research is needed to understand the multifarious nature of racism and the pathways by which it leads to poor health, it is feasible to monitor experiences of racial discrimination in national surveys.  相似文献   
993.
ObjectivesArginine (Arg) is known to possess numerous useful physiological properties and immunomodulatory effects. Th17 cells are a unique T-helper cell lineage. Regulation of Th17 cells plays a significant role in the pathogenesis of inflammatory disorders. This study investigated the effect of Arg on the exogenous advanced glycosylation end product (AGE)-induced Th17-mediated immune response.MethodsRats were randomly divided into three groups. The control BSA (CB) group was fed a common diet and given a tail vein injection of non-glycated bovine serum albumin (BSA). The control AGE (CA) group was fed the common diet and injected with 2 mg AGE-BSA. Arg-AGE (AA) group was fed the Arg-supplemented diet and injected with 2 mg AGE-BSA. The experimental diets were identical in energy and nutrient distributions except for the amino acid content. Arg provided 2% of the total energy. Tail vein injections and diets were given daily. After 10 d, all rats were sacrificed, and blood samples were collected for further analysis.ResultsThe AA group had the highest inducible nitric oxide (NO) synthase expression and plasma NO levels. The percentage of Foxp3 T-regulatory cells in the AA group was lower than those of the CA and CB groups. Transforming growth factor-β1, interleukin (IL)-6, and IL-17A gene expression was higher in the AGE-administered groups. The AA group had higher TGF-β1 and IL-17A expression than did the CA group.ConclusionThese results suggest that in a condition of exogenous AGE administration, supplemental dietary Arg resulted in a more pronounced IL-23/IL-17 immune response, possibly by increasing NO secretion.  相似文献   
994.
ObjectivesThis study investigated the effects of glutamine (Gln) supplementation on gene expressions of inflammatory mediators and cytokines associated with T-helper cell type 17 (Th17) regulation in diabetic rats.MethodsThere were one normal control group and two diabetic groups in this study. Rats in the normal control group were fed a regular chow diet. One diabetic group (DM) was fed a common semipurified diet, and the other diabetic group received a diet in which part of the casein was replaced by Gln (DM-Gln), which provided 25% of the total amino acid nitrogen for 8 wk. Diabetes was induced by an intraperitoneal injection of nicotinamide followed by streptozotocin. Rats with blood glucose levels exceeding 200 mg/dL were considered diabetic. Blood samples and blood mononuclear cells of the animals were collected at the end of the study for further analysis.ResultsGene expressions of transforming growth factor-β1 and interleukin-17A did not differ in blood mononuclear cells among the three groups. Expressions of interleukin-6, interleukin-23, monocyte chemotactic protein-1, and the receptor of the advanced glycated endproducts gene were higher in blood mononuclear cells and the ratio of reduced to oxidized glutathione was lower in erythrocytes in the DM group than in the normal control group. Messenger RNA expressions of these genes were lower, whereas the ratio of reduced to oxidized glutathione was higher in the DM-Gln group than in the DM group.ConclusionSupplemental dietary Gln increased the antioxidant potential and downregulated the expressions of inflammatory mediators. However, Th17 might not be an important involved pathway and the regulatory effect of Gln on Th17 immune response was not obvious in this animal model.  相似文献   
995.

Objective

To report a metastatic colorectal cancer patient with hyperbilirubinemia treated with a combination of bevacizumab and FOLFIRI (5-fluorouracil, leucovorin, and irinotecan) using uridine diphosphate glucuronosyl transferase (UGT1A1) genotyping.

Clinical Presentation and Intervention

A 46-year-old male was diagnosed with rectosigmoid colon cancer with liver metastases and hyperbilirubinemia presenting with severe jaundice. UGT1A1 genotyping was used before therapy to ascertain whether genotype-adjusted dosages of irinotecan plus bevacizumab could alleviate the toxicity. Then, the patient was treated with FOLFIRI.

Conclusion

The FOLFIRI regimen was successfully used in this patient without concerns regarding toxicity.Key Words: UGT1A1, Liver dysfunction, Hyperbilirubinemia, FOLFIRI, Bevacizumab  相似文献   
996.

Objective

The aim of this study was to investigate the effect of gender on symptom presentation and quality of life of patients with erosive esophagitis (EE) and nonerosive reflux disorder (NERD).

Subjects and Methods

Medical records from patients with gastroesophageal reflux disease (GERD) between January and December 2009 were reviewed. The patients were assigned to either the EE or the NERD group. The general demographic data, the modified Chinese GERDQ scores and the Short Form (SF)-36 life quality questionnaire scores of the two groups of patients were compared.

Results

Of the 261 patients, 87 (33.3s%), 86 (33.0s%) and 88 (33.7s%) patients were classified into the EE, the NERD and the control groups, respectively. The patients in the EE group were significantly older (48.94 ± 17.38 vs. 43.34 ± 12.67 years), were predominately male (58.6 vs. 39.5s%), had more frequently hiatal hernia (34.5 vs 17.4s%), had a higher body weight (67.57 ± 15.13 vs. 61.06 ± 11.08 kg) and a higher body mass index (24.09 ± 4.61 vs. 22.68 ± 3.12) than those in the NERD group. The GERD-specific symptom scores and the general life quality scores of the EE and the NERD groups were similar, and both groups had lower life quality scores than the control group did. The female patients with NERD had a higher frequency of GERD symptoms and lower quality of life scores. Gender had no effect on symptom scores or life quality scores in the EE group.

Conclusion

The GERD-specific symptom severity and general quality of life scores of the EE and the NERD patients were similar. Gender had a great influence on symptom presentation and quality of life in patients with NERD, but not in those with EE.Key Words: Erosive esophagitis, Gastroesophageal reflux disease, Gender, Quality of life, Nonerosive reflux disease  相似文献   
997.
The effect of the intra-arterial injection of 5 to 10 microng of sodium nitroprusside on the caliber of normal and diseased coronary arteries was evaluated in 21 patients during diagnostic cardiac catheterization. In addition, the effect of intra-graft injection of 5 microng of the same agent on the blood flow in aorta-right coronary artery saphenous vein bypass grafts was also evaluated intra-operatively in two patients. The compound induced an increase in the caliber of both normal and stenosed coronary arteries as well as an increase of flow in the grafts. Consistent with measurements of coronary flow response to sodium nitroprusside, angina pectoris which developed in four patients during cardiac catheterization was immediately relieved and the ischemic ST-segment depression significantly reversed after injection of 5 to 10 microng of the drug into the left main coronary artery. Within the dose range used, the drug caused no significant effect on systemic blood pressure or apparently deleterious electrophysiologic changes. No side effects were observed. We conclude that the primary direct action of sodium nitroprusside in the human coronary artery is vasodilatory.  相似文献   
998.
Calcitonin gene-related peptide has potent vasodilatory and inotropic actions. The aim of this study was to characterize the changes in this peptide in children with varying degrees of heart failure secondary to congenital heart disease with left to right shunt and to assess its relationship to systolic pulmonary arterial pressure. Plasma calcitonin gene-related peptide levels were measured in 131 children including 13 healthy ones, 43 with various degrees of heart failure secondary to congenital heart disease, and 75 with congenital heart disease without heart failure. In patients with heart failure, calcitonin gene-related peptide concentrations were markedly elevated (15.8 +/- 2.1 pg/mL) as compared with healthy control subjects (7.0 +/- 0.8 pg/mL, P < 0.05) or patients with congenital heart disease but without heart failure (18.6 +/- 1.2 pg/mL, P < 0.01). Compared with the controls, there were highly significant stepwise increases in the calcitonin gene-related peptide levels in the mild (n = 15), moderate (n = 12), and severe (n = 16) heart failure subgroups by 1.5, 1.7 and 3.4 fold, respectively. The plasma calcitonin gene-related peptide levels also correlated directly with the pulmonary arterial systolic pressure (r = 0.515, P < 0.0001). The results of this study indicate that congestive heart failure secondary to congenital heart disease with increased pulmonary flow is associated with elevated levels of calcitonin gene-related peptide that are related to disease severity. Pulmonary overcirculation may play a role in upregulation of calcitonin gene-related peptide in congestive heart failure.  相似文献   
999.
OctreoTher ((90)Y-DOTA-D-Phe(1)-Tyr(3)-octreotide, a.k.a. (90)Y-SMT 487) consists of a somatostatin peptide analogue (Tyr(3)-octreotide), coupled with a complexing moiety (DOTA), and labeled with a tightly bound beta-emitter (yttrium-90). By targeting somatostatin receptor-positive tumors (as imaged by OctreaScan it may deliver a tumoricidal dose of radiation. Phase I clinical trials, conducted in patients with neuroendocrine tumors, established the safety and tolerability of the dose selected for further study and demonstrated the capacity of OctreoTher to deliver radiation doses to tumors that resulted in significant neuroendocrine tumor shrinkage. Novartis-sponsored phase II studies will soon begin to test the efficacy of OctreoTher in breast and small cell lung cancer. A fixed-dose regimen of 120 mCi/cycle x 3 cycles administered with concomitant amino acid infusion has been chosen for the study. Phase I data and published literature support that this fixed dose regimen will be safely tolerated.  相似文献   
1000.
BACKGROUND/AIMS: To compare the accuracy between EUS (endoscopic ultrasound), ERCP (endoscopic retrograde cholangiopancreatography), CT (computed tomography), and transabdominal US (ultrasound) in the detection and staging of primary ampullary tumors. We will also try to discuss the influence of endobiliary stent on EUS in staging ampullary tumors. METHODOLOGY: Twenty-one patients with ampullary tumors were evaluated by EUS, ERCP, CT, and US before operation. The accuracy was assessed with TNM staging and compared with the surgical-pathological findings. RESULTS: EUS was superior to CT and US in detecting ampullary tumors, but EUS and ERCP are of similar sensitivity (EUS 95%, ERCP 95%, CT 19%, US 5%). EUS was superior to CT and US in T staging (EUS 75%, CT 5%, US 0%) and detecting lymph node metastasis (EUS 50%, CT 33%, US 0%) of ampullary tumors. The accuracy of EUS in T and N staging of ampullary tumors tended to be decreased in the presence of endobiliary stent (stenting: T 71%, N 75%; nonstenting T 83%, N 100%), but there was no statistical significance. CONCLUSIONS: EUS was superior to CT and US in assessing primary ampullary tumors, but it was not significantly superior to ERCP in detecting ampullary tumors. The presence of endobiliary stent may decrease the accuracy of EUS in staging ampullary tumors.  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