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   11235篇
  免费   1041篇
  国内免费   15篇
耳鼻咽喉   79篇
儿科学   520篇
妇产科学   310篇
基础医学   1691篇
口腔科学   264篇
临床医学   1327篇
内科学   2114篇
皮肤病学   342篇
神经病学   1031篇
特种医学   242篇
外国民族医学   4篇
外科学   1101篇
综合类   233篇
一般理论   21篇
预防医学   1339篇
眼科学   190篇
药学   742篇
中国医学   16篇
肿瘤学   725篇
  2023年   155篇
  2022年   234篇
  2021年   425篇
  2020年   279篇
  2019年   393篇
  2018年   436篇
  2017年   319篇
  2016年   349篇
  2015年   390篇
  2014年   443篇
  2013年   582篇
  2012年   902篇
  2011年   941篇
  2010年   476篇
  2009年   336篇
  2008年   607篇
  2007年   663篇
  2006年   558篇
  2005年   611篇
  2004年   543篇
  2003年   440篇
  2002年   477篇
  2001年   105篇
  2000年   123篇
  1999年   111篇
  1998年   91篇
  1997年   58篇
  1996年   71篇
  1995年   62篇
  1994年   49篇
  1993年   62篇
  1992年   71篇
  1991年   53篇
  1990年   51篇
  1989年   48篇
  1988年   29篇
  1987年   35篇
  1986年   41篇
  1985年   45篇
  1984年   49篇
  1983年   46篇
  1982年   34篇
  1981年   24篇
  1980年   35篇
  1979年   35篇
  1978年   25篇
  1977年   23篇
  1974年   20篇
  1973年   25篇
  1972年   31篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Objectives Even in the days of modern microsurgery, the removal of a brain stem lesion remains a surgical challenge. Especially when operating on children, the prognosis is directly related to the radicality of the resection; however, a radical resection is often associated with surgical morbidity. Intraoperative neuromonitoring could help to minimise the surgical morbidity, but few studies have been performed to clarify the value of this monitoring. We investigated a prospective series of 21 patients with lesions involving the brain stem for the prognostic value and benefits of neuromonitoring.Methods We performed intraoperative neuromonitoring of cranial nerve function by electromyography (EMG) and motor evoked potential (MEP). The results were correlated with postoperative neurological deficits.Conclusions There is a good correlation between intraoperative neurophysiological events and postoperative neurological deficits in patients with lesions of the brain stem. In general, transient, prolonged, spontaneous activity in EMG is associated with a transient paresis of the respective muscle, whereas a permanent spontaneous activity is associated with a permanent deficit. Intraoperative neuromonitoring reliably predicts postoperative neurological function in patients with tumours of the lower brain stem and fourth ventricle. This neuromonitoring guides the neurosurgeon in the operation and may decrease surgical morbidity. We recommend using monitoring of MEP and EMG of the lower cranial nerves in surgery on all patients with lesions involving the lower brain stem and fourth ventricle.  相似文献   
42.
Few bureaucratic appointments have raised as many eyebrows as the announcement that controversial health economist Jane Fulton would become Alberta's deputy minister of health. A staunch supporter of private health care, Fulton joins the Alberta ministry just as Premier Ralph Klein's Progressive Conservatives gear up for a battle with Ottawa over two-tier medicine.  相似文献   
43.
3-(1-Methylethyl)-2-(4-methoxyphenyl)-3H-naphth[1,2-d] imidazole (MDL-035) has antiinflammatory activity in various antiinflammatory models such as carrageenin and nystatin oedemas, cotton pellet granuloma and adjuvant arthritis. The antiinflammatory potency of MDL-035 is greater than that of acetylsalicylic acid and phenylbutazone, but lower than that of indomethacin. MDL-035 has practically no gastroulcerogenic activity in rats, does not affect water or salt excretion, has no hormonal or antihormonal effects and has no other unwanted pharmacological effects. Its acute toxicity is very low.  相似文献   
44.
OBJECTIVE: To examine the association between socioeconomic position and coping strategies in musculoskeletal pain. DESIGN AND SUBJECTS: Cross-sectional study of a random sample of 40- and 50-year-old Danes, participation rate 69%, n=7,125. The study included 1,287 persons who reported functional limitations due to musculoskeletal pain. METHODS: Data was collected by postal questionnaires and scales were developed on problem-solving coping and avoidant coping, based on a range of preliminary studies. Multivariate logistic regression analyses was used to study the correlation with socioeconomic position, measured by occupational social class. RESULTS: Among women, there was no correlation between social class and avoidant coping, but a significant decrease in the use of problem-solving coping by decreasing social class, adjusted odds ratio (OR) = 2.64 (95% confidence interval (CI) 1.31-5.32) in social class V vs social classes I + II. Among men, there was no correlation between social class and problem-solving coping, but a significant increase in the use of avoidant coping with decreasing social class, adjusted OR = 3.31 (95% CI 1.75-6.25) in V vs I + II. CONCLUSION: It is important for clinicians who advise and support patients in their response to musculoskeletal pain to be aware of socioeconomic differences in coping strategies. Gender differences in the association between socioeconomic factors and coping should be further investigated.  相似文献   
45.
The T-cell recognition of HLA-DR-peptide complexes is generally restricted by the polymorphism of the DRB molecules but pluriallelic restriction has been described. The molecular basis of restriction and promiscuity of such peptide-specific responses is poorly understood. We isolated a panel of T-cell lines specific for the tetanus toxin peptide p2 (TT830-843) exhibiting pluriallelic restriction by DR11 and DR8 alleles. Fine restriction specificity of the T-cell lines was examined in functional assays against DR oligotyped APCs expressing different variants of DR11 and DR8 alleles. Our results show that (a) polymorphisms between serologically related alleles are relevant in terms of restriction of the peptide-specific T-cell response; in some instances, a single amino acid substitution can determine the restriction of a T-cell line; (b) different patterns of restriction are not the result of specific differences in DR-p2 binding as p2 peptide binds to all DR11 and DR8 alleles tested (DRB1* 1101, -1102, -1103, -1104, 110X, -0801, -0802, -0803, and -0806); and (c) pluriallelic restriction of the peptide-specific T-cell responses correlates with the presence of a DRB1 α-helix motif (67-71-86) shared by some DR11 and DR8 alleles. Possible implications of pluriallelic restriction of peptide-specific T-cell response in autoimmune disorders associated with DR11 and DR8 are discussed.  相似文献   
46.
47.
Treatment and prognostic factors in patients with hepatocellular carcinoma.   总被引:4,自引:0,他引:4  
INTRODUCTION: Hepatocellular carcinoma is a leading cause of death from cancer worldwide. Survival of patients depends on tumor extension and liver function, but yet there is no consensual prognostic model. AIMS: To evaluate the influence on survival of pretreatment parameters (clinico-laboratorial, liver function, tumor extension, Okuda and Cancer of the Liver Italian program (CLIP) staging) and treatment modalities. METHODS: We retrospectively analyzed 207 patients, diagnosed between 1993 and 2003. The initial treatment was: surgery--six patients; radiofrequency ablation--21; percutaneous ethanol injection--29; transarterial chemoembolization--49; tamoxifen--49; supportive care alone--53. Factors determining survival were assessed by Kaplan-Meier method and Cox regression models. RESULTS: Median survival was 24 months. In univariate analysis, Child-Pugh classification and Model for end-stage liver disease (MELD) score, portal vein thrombosis (PVT), tumor size, number of lesions, Okuda and CLIP scores were all associated with prognosis (P < 0.001). Alpha-fetoprotein levels were not predictive of survival. Independent predictors of survival were ascites, bilirubin, PVT and therapeutic modalities (P < 0.001). In early stage hepatocellular carcinoma (HCC), survival was similar for both percutaneous ablation modalities, either radiofrequency or ethanol injection (P = NS). In advanced HCC, survival was better in patients receiving tamoxifen than supportive care alone (P < 0.001). CONCLUSION: This study reinforces the importance of baseline liver function (Child-Pugh classification and MELD score) in the survival of patients with HCC, although staging systems allowed the stratification of patients in different prognostic groups. Ascites, bilirubin and PVT were independent pretreatment predictors of survival. All treatments influenced the patient's outcome, whether in early or advanced stages.  相似文献   
48.
49.
BACKGROUND: Oxytocin is known to reduce anxiety and stress in social interactions as well as to modulate approach behavior. Recent studies suggest that the amygdala might be the primary neuronal basis for these effects. METHODS: In a functional magnetic resonance imaging study using a double-blind, placebo-controlled within-subject design, we measured neural responses to fearful, angry, and happy facial expressions after intranasal application of 24 IU oxytocin compared with placebo. RESULTS: Oxytocin reduced right-sided amygdala responses to all three face categories even when the emotional content of the presented face was not evaluated explicitly. Exploratory whole brain analysis revealed modulatory effects in prefrontal and temporal areas as well as in the brainstem. CONCLUSIONS: Results suggest a modulatory role of oxytocin on amygdala responses to facial expressions irrespective of their valence. Reduction of amygdala activity to positive and negative stimuli might reflect reduced uncertainty about the predictive value of a social stimulus and thereby facilitates social approach behavior.  相似文献   
50.
BACKGROUND: In animals, strong evidence exists for an association between testosterone and aggression. In humans, and particularly in children and adolescents, findings have been less consistent. Previous research has suggested that this may partly be due to moderating effects of other factors, e.g., hormones. This study aims to investigate the moderating effect of cortisol on the relationship between testosterone and subtypes of aggression in delinquent male adolescents. METHODS: Participants were 103 boys (mean age 13.7) referred to a delinquency diversion program. Testosterone and cortisol levels were determined from saliva samples collected during resting conditions and related to self-report scores on overt and covert aggression. RESULTS: Linear regression analyses revealed a significant interaction between cortisol and testosterone in relation to overt aggression, with a significant positive relationship between testosterone and overt aggression in subjects with low cortisol levels but not in subjects with high cortisol levels. Using the same model for covert aggression, no significant effects of testosterone, cortisol, or testosterone x cortisol interaction were found. CONCLUSIONS: These results indicate a moderating effect of cortisol on the relationship between testosterone and overt aggression in delinquent male adolescents. Implications and directions for future research are discussed.  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