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   394篇
  免费   21篇
  国内免费   12篇
耳鼻咽喉   1篇
儿科学   14篇
妇产科学   6篇
基础医学   40篇
口腔科学   24篇
临床医学   53篇
内科学   117篇
皮肤病学   3篇
神经病学   6篇
特种医学   74篇
外科学   19篇
综合类   18篇
预防医学   19篇
眼科学   1篇
药学   19篇
中国医学   1篇
肿瘤学   12篇
  2023年   4篇
  2022年   4篇
  2021年   4篇
  2020年   5篇
  2019年   5篇
  2018年   7篇
  2017年   4篇
  2016年   11篇
  2015年   5篇
  2014年   9篇
  2013年   15篇
  2012年   3篇
  2011年   6篇
  2010年   17篇
  2009年   24篇
  2008年   7篇
  2007年   19篇
  2006年   5篇
  2005年   3篇
  2004年   4篇
  2003年   3篇
  2002年   1篇
  2001年   4篇
  2000年   2篇
  1999年   5篇
  1998年   30篇
  1997年   30篇
  1996年   30篇
  1995年   25篇
  1994年   17篇
  1993年   19篇
  1992年   8篇
  1991年   3篇
  1990年   12篇
  1989年   12篇
  1988年   14篇
  1987年   18篇
  1986年   6篇
  1985年   4篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1981年   2篇
  1980年   3篇
  1979年   1篇
  1978年   1篇
  1977年   5篇
  1976年   3篇
  1975年   3篇
排序方式: 共有427条查询结果,搜索用时 15 毫秒
61.
Bone sarcomas in Paget disease: a study of 85 patients   总被引:5,自引:0,他引:5  
Smith  J; Botet  JF; Yeh  SD 《Radiology》1984,152(3):583-590
This is a comprehensive review of 85 patients who had bone sarcoma associated with Paget disease and who were seen at Memorial Sloan-Kettering Cancer Center between 1927 and 1982. There was an almost equal distribution of tumors in the axial and the appendicular skeletons. The pelvis, humerus, femur, and skull were the tumor sites in 80% of cases. The tumors were bulky large soft tissue masses. Lytic lesions were more common than sclerotic lesions. Mixed lytic and sclerotic lesions were much less common than either single type. Periosteal reaction was uncommon and found in less than 7%. Methylene diphosphonate scans of the bone often showed a cold area that was associated with marked increase in uptake on the gallium scan. Angiography, which was performed in 13 patients, was useful, but CT was much more helpful in showing the soft tissue mass as well as the extent of bony disease. Only three patients in this study survived for five years. Present chemotherapy protocols were disappointing in the treatment of this highly lethal tumor.  相似文献   
62.
Purpose: To examine the effects of phoneme-grapheme correspondence and phonemic awareness instruction on the encoding abilities of three pre-reading children with severe speech impairment (SSI). Method: Using a single subject multiple baseline design across behaviours and participants, children received phoneme-grapheme awareness instruction followed by instruction in segmenting, manipulating, and encoding consonant-vowel-consonant (CVC) pseudowords. Results: Generalization occurred to encoding of novel CVC pseudo- and real words for two of the three participants. Conclusions: Results suggest that phoneme-grapheme correspondence and phonemic awareness instruction is effective in developing encoding skills in children with SSI. Findings are consistent with those for other at-risk children.  相似文献   
63.
报道了氯仿重结晶的棉酚的化学性质,样品在不同温度下干燥恒重后,经熔点、薄层层析、紫外光谱、红外光谱、X-射线衍射、热重量分析、元素(C,H,Cl)分析及棉酚合量测定等一系列的分析,确证了在60℃以下棉酚与氯仿成溶剂化物(solvate)。随着干燥温度的升高或在室温长时间的贮存,此现象逐渐消失,100℃真空干燥恒重后成为纯棉酚。  相似文献   
64.
Predictive models of complex drug-drug interactions between multiple inhibitors and their metabolites have not been evaluated. The purpose of this study was to evaluate an interaction model for cytochrome P450 3A4 (CYP3A4) that incorporated the simultaneous reversible and irreversible inhibition by multiple inhibitors. Erythromycin (ERY) and diltiazem (DTZ), and their major metabolites, N-desmethylerythromycin (nd-ERY) and N-desmethyldiltiazem (nd-DTZ), were chosen to evaluate the model. k(inact) (rate constant for maximal inactivation), K(I) (inhibitor concentration at 50% maximal inactivation), and K(i) (reversible inhibition constant) were estimated for ERY, DTZ, nd-ERY, and nd-DTZ, respectively, using cDNA-expressed CYP3A4 and human liver microsomes under optimal experimental conditions. To evaluate the interaction model, combinations of inhibitors and metabolites were incubated at concentrations equal to K(I), (1/2)K(I), and 2K(I) of each inhibitor for specified durations in both enzyme systems. The models were further evaluated by the incubation of combinations of inhibitors with the substrate testosterone for 10 min. CYP3A4 inhibition in the presence of drug mixtures was predicted from the inhibition parameters determined for each drug or metabolite alone. The CYP3A4 activity in the presence of multiple inhibitors was well predicted by the model incorporating additive irreversible inhibition as modified by mutual competitive inhibition (percent mean error and percent mean absolute error ranged from -0.06 to 0.04 and from 0.03 to 0.09, respectively). In conclusion, the additive model predicted the combined effect of multiple inhibitors on CYP3A inhibition in vitro. However, simultaneous reversible and irreversible inhibition effects should be taken into account in a reaction mixture of substrate and multiple inhibitors of CYP3A4.  相似文献   
65.

Background and purpose:

Angiotensin II receptor antagonists (ARBs), originally developed for antihypertensive properties, have pleiotropic effects including direct vascular actions. We tested the hypothesis that the ARB irbesartan would be effective against micro- and macrovascular complications of the prediabetic metabolic syndrome using the obese, insulin-resistant JCR : LA-cp rat that exhibits micro- and macrovascular disease with ischaemic myocardial lesions and renal disease.

Experimental approach:

Obese male rats were treated with irbesartan (30 mg·kg−1·day−1, incorporated into chow) from 12 to 25 weeks of age.

Key results:

Irbesartan treatment caused no change in food intake or body weight. Fasting glycaemic control of the JCR : LA-cp rats was marginally improved, at the expense of increased plasma insulin levels (∼50%). Fasting plasma triglycerides were marginally reduced (∼25%), while cholesterol concentrations were unchanged. Elevated concentrations of adiponectin, monocyte chemotactic protein-1 and plasminogen activator inhibitor-1 were reduced along with severity of glomerular sclerosis. Macrovascular dysfunction (aortic hypercontractile response to noradrenergic stimulus and reduced endothelium-dependent relaxation) was improved and frequency of ischaemic myocardial lesions reduced (62%).

Conclusions and implications:

Irbesartan reduces markers of inflammation and prothombotic status, improves macrovascular function and reduces glomerular sclerosis and myocardial lesions in a model of the metabolic syndrome. Unlike pharmaceutical agents targeted on metabolic dysfunction, irbesartan reduced end-stage disease without major reduction of plasma lipids or insulin. The protective effects appear to be secondary to unknown intracellular mechanisms, probably involving signal transduction pathways. Understanding these would offer novel pharmaceutical approaches to protection against cardiovascular disease.  相似文献   
66.
67.
The rate of alloimmunization to platelet-specific antigens associated with platelet glycoproteins (GPs) IIb-IIIa and Ib/IX was studied in 293 multiply transfused thrombocytopenic patients. Antibodies to platelet-specific antigens were measured with a solid-phase assay using platelet GP IIb-IIIa or Ib/IX as the antigenic targets. Nine patients were found to have antibodies to platelet GP IIb-IIIa, and no patients had antibodies to platelet GP Ib/IX. In six of these nine patients, the specificity of the antibody was shown by using GP IIb-IIIa from donors with different platelet-specific antigen phenotypes. In the remaining three patients with antibodies to platelet GP IIb-IIIa, no specificity could be identified. These patients had autoimmune thrombocytopenia in association with lymphoma. The alloimmunization rate to platelet-specific antigens associated with GP IIb-IIIa was 2 percent, whereas the rate of alloimmunization to HLA antigens was 23 percent. Of the patients alloimmunized to HLA antigens, 9 percent also had antibodies to platelet-specific antigens. A poor response to HLA-identical platelet transfusions was observed only in those patients with positive assays in the solid-phase test. These results suggest that the incidence of antibodies to platelet-specific antigens carried on GP IIb-IIIa is low. Platelet-specific antibodies may be found more frequently in patients alloimmunized to HLA antigens than in those not so alloimmunized.  相似文献   
68.
Objective India is a country with the availability of a large number of pharmaceutical preparations as branded generics. At the time of this study there was no established pharmacovigilance system at the national level except a co‐ordinating centre at the national capital. The study site was a tertiary care teaching hospital with a bed capacity of 500 and with an average of 200 outpatient visits and 50 inpatient admissions per day. The hospital did not have any system of monitoring and documenting adverse drug reactions. The objective of the study was to introduce an adverse drug reaction (ADR) monitoring programme at a tertiary care teaching hospital and assess ADR‐related issues in both inpatient and outpatient departments. Method All departments willing to report ADRs were included in the study, which was carried out for one year. Physicians and nurses filled in the notification forms when they encountered suspected ADR cases. These cases were then assessed by a panel of four judges. According to Naranjo's algorithm, the ADRs were assessed and classified based on World Health Organization (WHO) classification. Key findings A total of 288 suspected cases were reported and 264 ADRs were confirmed by the panel. According to Naranjo's probability scale, 83 cases were categorized as ‘probable’, 181 cases were classified as ‘possible’, and none were classified as ‘unlikely’ or ‘definite’. The most common classes of drugs involved were antibiotics (25%), psychotropics (20%), analgesic and cardiovascular agents (14% each). Generalised itch and rash, tremors, urticarial drug reaction, oral ulcer, gastritis and akathesia and extrapyramidal symptoms were found to be the most common ADRs observed; 2.1% of the patients in the studied departments had ADRs. Conclusion The ADR reporting system was initiated at the hospital and was well received by the physicians. Appreciable participation of physicians was noted during the study in reporting ADRs. The study also gave an insight into the awareness of physicians about ADR‐related issues. The number of ADRs reported was reasonably comparable with the findings of other authors from India.  相似文献   
69.
70.
Authors – Weinberg SM, Naidoo SD, Bardi KM, Brandon CA, Neiswanger K, Resick JM, Martin RA, Marazita ML Objective – Various lines of evidence suggest that face shape may be a predisposing factor for non‐syndromic cleft lip with or without cleft palate (CL/P). In the present study, 3D surface imaging and statistical shape analysis were used to evaluate face shape differences between the unaffected (non‐cleft) parents of individuals with CL / P and unrelated controls. Methods – Sixteen facial landmarks were collected from 3D captures of 80 unaffected parents and 80 matched controls. Prior to analysis, each unaffected parent was assigned to a subgroup on the basis of prior family history (positive or negative). A geometric morphometric approach was utilized to scale and superimpose the landmark coordinate data (Procrustes analysis), test for omnibus group differences in face shape, and uncover specific modes of shape variation capable of discriminating unaffected parents from controls. Results – Significant disparity in face shape was observed between unaffected parents and controls (p < 0.01). Notably, these changes were specific to parents with a positive family history of CL / P. Shape changes associated with CL / P predisposition included marked flattening of the facial profile (midface retrusion), reduced upper facial height, increased lower facial height, and excess interorbital width. Additionally, a sex‐specific pattern of parent‐control difference was evident in the transverse dimensions of the nasolabial complex. Conclusions – The faces of unaffected parents from multiplex cleft families displayed meaningful shape differences compared with the general population. Quantitative assessment of the facial phenotype in cleft families may enhance efforts to discover the root causes of CL /P.  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