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   5005篇
  免费   292篇
  国内免费   13篇
耳鼻咽喉   33篇
儿科学   146篇
妇产科学   89篇
基础医学   660篇
口腔科学   53篇
临床医学   560篇
内科学   947篇
皮肤病学   53篇
神经病学   631篇
特种医学   144篇
外科学   659篇
综合类   38篇
一般理论   6篇
预防医学   569篇
眼科学   113篇
药学   296篇
中国医学   18篇
肿瘤学   295篇
  2024年   11篇
  2023年   26篇
  2022年   85篇
  2021年   103篇
  2020年   71篇
  2019年   103篇
  2018年   122篇
  2017年   80篇
  2016年   102篇
  2015年   122篇
  2014年   150篇
  2013年   211篇
  2012年   350篇
  2011年   360篇
  2010年   179篇
  2009年   175篇
  2008年   342篇
  2007年   343篇
  2006年   322篇
  2005年   341篇
  2004年   278篇
  2003年   255篇
  2002年   257篇
  2001年   67篇
  2000年   76篇
  1999年   68篇
  1998年   55篇
  1997年   40篇
  1996年   41篇
  1995年   32篇
  1994年   21篇
  1993年   22篇
  1992年   38篇
  1991年   37篇
  1990年   31篇
  1989年   33篇
  1988年   16篇
  1987年   22篇
  1986年   25篇
  1985年   19篇
  1984年   19篇
  1983年   17篇
  1982年   18篇
  1980年   16篇
  1979年   17篇
  1973年   11篇
  1971年   12篇
  1969年   10篇
  1968年   11篇
  1965年   11篇
排序方式: 共有5310条查询结果,搜索用时 15 毫秒
151.
Objective. To investigate the extent to which early radiologic damage is predicted by joint inflammation in patients with newly diagnosed rheumatoid arthritis (RA). Methods. Regression analysis was performed on 1-year progression of total radiologic damage for baseline characteristics and cumulative disease activity measures, and the effects of continued joint inflammation on the progression of damage in separate joint groups were investigated. Results. Odds ratios for progression of total damage were 12 for the presence of rheumatoid factor, 5 for the presence of damage at baseline, and 2 for cumulative joint inflammation. A positive association between continued joint inflammation and progression of damage was found to be statistically significant for most joint groups. Conclusion. Progression of radiologic damage in patients with newly diagnosed RA is independently associated with the presence of rheumatoid factor and damage at baseline and with cumulative joint inflammation.  相似文献   
152.
Zeitschrift für Psychodrama und Soziometrie - Dieser Beitrag der Zeitschrift für Psychodrama und Soziometrie beleuchtet das psychodrama-therapeutische Gruppensetting im virtuellen Raum...  相似文献   
153.
Neuroinflammation triggered by the expression of damaged-associated molecular patterns released from dying cells plays a critical role in the pathogenesis of ischemic stroke. However, the benefits from the control of neuroinflammation in the clinical outcome have not been established. In this study, the effectiveness of intranasal, a highly efficient route to reach the central nervous system, and intraperitoneal dexamethasone administration in the treatment of neuroinflammation was evaluated in a 60-min middle cerebral artery occlusion (MCAO) model in C57BL/6 male mice. We performed a side-by-side comparison using intranasal versus intraperitoneal dexamethasone, a timecourse including immediate (0 h) or 4 or 12 h poststroke intranasal administration, as well as 4 intranasal doses of dexamethasone beginning 12 h after the MCAO versus a single dose at 12 h to identify the most effective conditions to treat neuroinflammation in MCAO mice. The best results were obtained 12 h after MCAO and when mice received a single dose of dexamethasone (0.25 mg/kg) intranasally. This treatment significantly reduced mortality, neurological deficits, infarct volume size, blood–brain barrier permeability in the somatosensory cortex, inflammatory cell infiltration, and glial activation. Our results demonstrate that a single low dose of intranasal dexamethasone has neuroprotective therapeutic effects in the MCAO model, showing a better clinical outcome than the intraperitoneal administration. Based on these results, we propose a new therapeutic approach for the treatment of the damage process that accompanies ischemic stroke.Electronic supplementary materialThe online version of this article (10.1007/s13311-020-00884-9) contains supplementary material, which is available to authorized users.  相似文献   
154.
OBJECTIVES: This study was designed to assess the effect of flavanol-rich food on the circulating pool of bioactive nitric oxide (NO) and endothelial dysfunction in smokers. BACKGROUND: Studies suggest that smoking-related vascular disease is caused by impaired NO synthesis and that diets rich in flavanols can increase bioactive NO in plasma. METHODS: In smokers (n = 11), the effects of flavanol-rich cocoa on circulating NO species in plasma (RXNO) measured by reductive gas-phase chemiluminescence and endothelial function as assessed by flow-mediated dilation (FMD) were characterized in a dose-finding study orally administering cocoa containing 88 to 370 mg flavanols and in a randomized double-blind crossover study using 100 ml cocoa drink with high (176 to 185 mg) or low (<11 mg) flavanol content on two separate days. In addition to cocoa drink, ascorbic acid and NO-synthase inhibitor L-NMMA (n = 4) were applied. RESULTS: There were significant increases in RXNO (21 +/- 3 nmol/l to 29 +/- 5 nmol/l) and FMD (4.5 +/- 0.8% to 6.9 +/- 0.9%, each p < 0.05) at 2 h after ingestion of 176 to 185 mg flavanols, a dose potentially exerting maximal effects. These changes correlated with increases in flavanol metabolites. Cocoa-associated increases in RXNO and FMD were reversed by L-NMMA. Ascorbic acid had no effect. CONCLUSIONS: The circulating pool of bioactive NO and endothelium-dependent vasodilation is acutely increased in smokers following the oral ingestion of a flavanol-rich cocoa drink. The increase in circulating NO pool may contribute to beneficial vascular health effects of flavanol-rich food.  相似文献   
155.
A close relationship between alcohol consumption and hypertension has been established, but it is unclear whether there is a threshold level for this association. In addition, it has infrequently been studied in longitudinal studies and in black people. In a cohort study, 8334 of the Atherosclerosis Risk in Communities (ARIC) Study participants, aged 45 to 64 years at baseline, who were free of hypertension and coronary heart disease had their blood pressures ascertained after 6 years of follow-up. Alcohol consumption was assessed by dietary interview. The type of alcoholic beverage predominantly consumed was defined by the source of the largest amount of ethanol consumed. Incident hypertension was defined as a systolic blood pressure >/=140 mm Hg or diastolic blood pressure >/=90 mm Hg or use of antihypertensive medication. There was an increased risk of hypertension in those who consumed large amounts of ethanol (>/=210 g per week) compared with those who did not consume alcohol over the 6 years of follow-up. The adjusted odds ratios (95% confidence interval) were 1.2 (0.85 to 1.67) for white men, 2.02 (1.08 to 3.79) for white women, and 2.31 (1.11 to 4.86) for black men. Only 4 black women reported drinking >210 g ethanol per week. At low to moderate levels of alcohol consumption (1 to 209 g per week), the adjusted odds ratios (95% confidence interval) were 0.88 (0.71 to 1.08) in white men, 0.89 (0.73 to 1.09) in white women, 1.71 (1.11 to 2.64) in black men, and 0.88 (0.59 to 1.33) in black women. Systolic and diastolic blood pressures were higher in black men who consumed low to moderate amounts of alcohol compared with the nonconsumers but not in the 3 other race-gender strata. Models with polynomial terms of alcohol exposure suggested a nonlinear association in white and black men. Higher levels of consumption of all types of alcoholic beverages were associated with a higher risk of hypertension for all race-gender strata. The consumption of alcohol in amounts >/=210 g per week is an independent risk factor for hypertension in free-living North American populations. The consumption of low to moderate amounts of alcohol also appears to be associated with a higher risk of hypertension in black men.  相似文献   
156.
157.
Complete healing is problematic as an endpoint for evaluating interventions for wound healing. The great heterogeneity of wounds makes it difficult to match groups, and this is only possible with multivariate stratification and/or very large numbers of subjects. The substantial time taken for wounds to heal necessitates a very lengthy study. Consequently, high quality randomised controlled trials demonstrating an effect of an intervention to a satisfactory level of statistical significance and with a satisfactory level of generalisability are extremely rare. This study determines that the healing of venous leg ulcers receiving multi‐component compression bandaging follows a linear trajectory over a 4‐week period, as measured by gross area healed, percentage area healed, and advance of the wound margin. The linear trajectories of these surrogates make it possible to identify an acceleration in healing resulting from an intervention, and allows self‐controlled or crossover designs with attendant advantages of statistical power and speed. Of the metrics investigated, wound margin advance was the most linear, and was also independent of initial ulcer size.  相似文献   
158.
The study aims to examine the knowledge and the practice of the precautionary measures taken by older adults in Hong Kong against the outbreak of severe acute respiratory syndrome (SARS). Overall, more than half the participants responded correctly that droplet transmission is one of the main transmission routes of SARS. Those who received formal education demonstrated that they acquired greater knowledge of the sources and precautionary measures for SARS. The types of precautionary measures used and the factors affecting their behaviours were discussed. The results of the study could help the health-care professionals develop appropriate health promotion and disease prevention programmes for older adults.  相似文献   
159.
PURPOSE: To correlate prenatal sonographic diagnosis of cystic lung malformations with fetopathologic findings after termination of pregnancy. METHODS: We retrospectively analyzed the data of 16 terminated cases in which a cystic lung lesion was diagnosed pre- or postnatally. RESULTS: On average, prenatal diagnosis was established on the 21(st) gestational week (range, 19-26 weeks). The cause of termination was severe polyhydramnios in 4 cases, nonimmune fetal hydrops in 4 cases, other congenital malformation in 5 cases (renal malformation, 2 cases; congenital diaphragmatic hernia, 3 cases), and obstetrical conditions (intrauterine death, placental abruption, spontaneous abortion) in 3 cases. In 11 cases, congenital cystic adenomatoid malformation (CCAM) was the presumptive prenatal diagnosis. Autopsy confirmed the prenatal diagnosis in 6 of them, while in the other 5 cases, an enteric cyst, a laryngeal atresia, an unidentified tumor, a pulmonary hypoplasia, and an extralobar pulmonary sequestration were found on histologic examination. On the other hand, the autopsy revealed CCAM in those 5 cases in which other malformations were suggested prenatally. CONCLUSION: The prenatal sonographic diagnosis of CCAM is difficult. Our cases emphasize the important role of fetopathology even today in the verification of prenatal diagnosis based on sonographic examinations.  相似文献   
160.
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