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   10543篇
  免费   851篇
  国内免费   28篇
耳鼻咽喉   113篇
儿科学   384篇
妇产科学   217篇
基础医学   1463篇
口腔科学   200篇
临床医学   967篇
内科学   2315篇
皮肤病学   203篇
神经病学   1001篇
特种医学   275篇
外科学   1771篇
综合类   92篇
一般理论   4篇
预防医学   781篇
眼科学   140篇
药学   619篇
中国医学   33篇
肿瘤学   844篇
  2023年   62篇
  2022年   119篇
  2021年   254篇
  2020年   160篇
  2019年   282篇
  2018年   335篇
  2017年   257篇
  2016年   240篇
  2015年   273篇
  2014年   375篇
  2013年   460篇
  2012年   626篇
  2011年   651篇
  2010年   415篇
  2009年   353篇
  2008年   474篇
  2007年   535篇
  2006年   501篇
  2005年   456篇
  2004年   408篇
  2003年   364篇
  2002年   352篇
  2001年   322篇
  2000年   326篇
  1999年   322篇
  1998年   113篇
  1997年   95篇
  1996年   99篇
  1995年   91篇
  1994年   100篇
  1993年   68篇
  1992年   198篇
  1991年   201篇
  1990年   172篇
  1989年   164篇
  1988年   128篇
  1987年   141篇
  1986年   127篇
  1985年   96篇
  1984年   74篇
  1983年   57篇
  1982年   34篇
  1981年   44篇
  1979年   57篇
  1978年   45篇
  1977年   39篇
  1976年   38篇
  1975年   33篇
  1974年   37篇
  1973年   38篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
We used regression analysis to compare the semiologic features of temporal lobe seizures that occur during sleep (TLS-S) and wake (TLS-W) in the same patient. Most semiologic features correctly lateralized seizure activity during either sleep or wake. No significant differences were found between TLS-S and TLS-W in the 18 semiologic features analyzed. The diagnostic value of TLS-S semiology is similar to that of TLS-W semiology.  相似文献   
992.

Background and purpose:

Previous results have shown that mice lacking in the group 1B phospholipase A2 (Pla2g1b) are resistant to obesity and diabetes induced by feeding a diabetogenic high-fat/high-carbohydrate diet. This study examined the potential of using the Pla2g1b inhibitor methyl indoxam as therapy to suppress diet-induced obesity and diabetes.

Experimental approach:

Male C57BL/6 mice were fed the diabetogenic diet with or without methyl indoxam supplementation. Body weight gain, fasting plasma glucose levels, glucose tolerance and postprandial lysophospholipid absorption were compared.

Key results:

Wild-type C57BL/6 mice fed the diabetogenic diet without Pla2g1b inhibitor showed 31 and 69% body weight gain after 4 and 10 weeks respectively. These animals also showed elevated plasma glucose levels and were glucose intolerant. In contrast, C57BL/6 mice fed the diabetogenic diet with 90 mg·kg−1 of methyl indoxam gained only 5% body weight after 10 weeks. These animals were also euglycaemic and displayed normal glucose excursion rates in glucose tolerance test. Methyl indoxam suppression of diet-induced body weight gain and glucose intolerance was correlated with the inhibition of Pla2g1b-mediated postprandial lysophospholipid absorption.

Conclusions and implications:

These results show that oral supplementation of a diabetogenic diet with the Pla2g1b inhibitor methyl indoxam effectively suppresses diet-induced obesity and diabetes in mice. This suggests that Pla2g1b inhibition may be a potentially effective oral therapeutic option for treatment of obesity and diabetes.  相似文献   
993.
Objectives The aims of this study were to evaluate the suitability of the spray congealing technique to produce solid lipid microparticles (SLMs) for topical administration and to study the skin permeation of a drug from SLMs compared with solid lipid nanoparticles (SLNs). Methods Econazole nitrate was used as model drug and Precirol ATO 5 as the lipidic carrier. SLMs and SLNs were both prepared at 5: 1, 10: 1 and 12.5: 1 lipid: drug weight ratios and characterised in terms of particle size, morphology, encapsulation efficiency and chemical analysis of the particle surface. SLMs and SLNs were also incorporated into HPMC K 100M hydrogels for ex‐vivo drug permeation tests using porcine epidermis. Key findings SLMs had particle sizes of 18–45 μm, while SLNs showed a mean diameter of 130–270 nm. The encapsulation efficiency was 80–100%. Permeation profiles of econazole nitrate were influenced by both particle size (significant difference until 9 h) and the amount of lipid. Conclusions The results confirm the usefulness of SLNs as carriers for topical administration and suggest the potential of SLMs for the delivery of drugs to the skin.  相似文献   
994.
Ferroelectric domain nucleation and growth in multiferroic BiFeO(3) is studied on a single-domain level by using piezoresponse force spectroscopy. Variation of local electromechanical response with dc tip bias is used to determine the size of the domain formed below the conductive scanning probe tip. The domain parameters are calculated self-consistently from the decoupled Green function theory by using tip geometry determined from the domain wall profile. The critical parameters of the nucleating domain and the activation energy for nucleation are determined. The switching mechanism is modeled by using the phase-field method, and comparison with experimental results shows that the nucleation biases are within a factor of approximately 2 of the intrinsic thermodynamic limit. The role of atomic-scale defects and long-range elastic fields on nucleation bias lowering is discussed. These measurements open a pathway for quantitative studies of the role of a single defect on kinetics and thermodynamics of first order bias-induced phase transitions and electrochemical reactions.  相似文献   
995.
We report the first case of a primary adrenal natural killer (NK)/T-cell nasal type lymphoma in adults. The patient presented with an enlarging left adrenal mass and the initial concern was for adrenocortical carcinoma. Surgical resection revealed NK/T-cell lymphoma. Rapid recurrence in the contralateral adrenal gland was treated with a single cycle of chemotherapy before he died due to infectious complications and progressive disease. This case demonstrates the aggressive presentation of a novel subset of primary adrenal lymphoma that should be considered in the differential diagnosis of a rapidly enlarging adrenal mass.  相似文献   
996.
The purpose of the study is to compare surrogate estimates of insulin sensitivity with a directly measured insulin sensitivity index, steady-state plasma glucose (SSPG) from insulin suppression test (IST), in subjects with hypertension. Two hundred and twenty-eight hypertensive patients who received IST for SSPG were included for analysis. Estimates from fasting measurements alone, homeostasis model assessment for insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI)), and indices from fasting and/or 2 h samples (ISI(0,120) and ISI(TX)) were calculated. In addition to Pearson and partial correlations, variance-component models were used to test the relationship between surrogate estimates of insulin sensitivity and SSPG. A large proportion of variance owing to covariates in the variance-component models indicated the goodness of model fit, irrespective of the independence among variables. SSPG was positively correlated with logarithmic transformation (Log) (HOMA-IR) and negatively correlated with QUICKI, Log (ISI(0,120)) and ISI(TX) (all P<0.0001). Log (ISI(0,120)) seemed to have a better correlation with SSPG (r=-0.72) than other measures in partial correlation. The proportion of variance owing to all covariates of Log (ISI(0,120)) and ISI(TX) were larger than those of Log (HOMA-IR) and QUICKI in the variance-component models. After adjustments for demographic and obesity covariates, the proportion of variance explained by Log (ISI(0,120)) were largest among the surrogate measures in the variance-component models. Our results showed that ISI(0,120) and ISI(TX) correlated better with SSPG than those used fasting measures alone (HOMA-IR and QUICKI). Log (ISI(0,120)) currently showing the strongest association with SSPG than other estimates is adaptable for use in large studies of hypertension.  相似文献   
997.
Alcohol consumption is associated with decreased antiretroviral adherence, and decreased adherence results in poorer outcomes. However the magnitude of alcohol's impact on survival is unknown. Our objective was to use a calibrated and validated simulation of HIV disease to estimate the impact of alcohol on survival. We incorporated clinical data describing the temporal and dose-response relationships between alcohol consumption and adherence in a large observational cohort (N=2,702). Individuals were categorized as nondrinkers (no alcohol consumption), hazardous drinkers (consume > or =5 standard drinks on drinking days), and nonhazardous drinkers (consume <5 standard drinks on drinking days). Our results showed that nonhazardous alcohol consumption decreased survival by more than 1 year if the frequency of consumption was once per week or greater, and by 3.3 years (from 21.7 years to 18.4 years) with daily consumption. Hazardous alcohol consumption decreased overall survival by more than 3 years if frequency of consumption was once per week or greater, and by 6.4 years (From 16.1 years to 9.7 years) with daily consumption. Our results suggest that alcohol is an underappreciated yet modifiable risk factor for poor survival among individuals with HIV.  相似文献   
998.
Pneumocandins have concentration-dependent antifungal activity and higher dose of caspofungin (HD-CAP) in combination with other licensed antifungal therapy (OLAT) may improve response. Thirty-four patients who received HD-CAP were compared with 63 patients who received standard dose (SD)-CAP. There were no differences between the groups in either patient or disease characteristics. Significantly more patients in the HD-CAP arm had extrapulmonary infections (29 vs 8% in SD group; P=0.0053), and non-Aspergillus species infection (21 vs 6%; P=0.05) and had received prior antifungal therapy (71 vs 33%; P=0.0004). No serious adverse reactions were noted in patients receiving HD- or SD-CAP therapy. Twelve weeks after treatment commenced 44% had a complete or partial response compared with 29% in SD-CAP group (P=0.1). Logistic regression analysis showed a significant probability of a favorable outcome at 12 weeks in patients who received HD-CAP (OR 3.066, 95% CI, 1.092-8.61; P=0.033). This may in part reflect higher number of patients in HD group had received granulocyte-macrophage colony-stimulating factor (41 vs 14% in SD group; P=0.04) and/or interferon gamma (26 vs 5% in SD group; P=0.003) immune enhancement. Further studies are needed to evaluate efficacy of HD-CAP in severely immunosuppressed cancer patients with invasive fungal infections.  相似文献   
999.
Transmission of human herpesvirus 8 (HHV-8) may occur through various routes including breastfeeding and sexual intercourse. We attempted to detect HHV-8 infection in nine HIV-positive couples discordant for Kaposi's sarcoma who maintained a monogamous sexual relationship for at least one year. By quantitative real-time polymerase chain reaction and HHV-8 genotyping we provide strong evidence for the sexual transmission of HHV-8 in this unique cohort.  相似文献   
1000.
The expansion of human immunodeficiency virus (HIV) care and treatment in Africa and other resource-limited settings has begun to mitigate the impact of the acquired immunodeficiency syndrome pandemic. As this expansion has occurred, critical research has been conducted that has helped to define best practices and establish guidelines in HIV care. However, despite this research, a tremendous gap exists between the actual delivery of care and those strategies with proven efficacy in the clinical research setting: the program-implementation gap. The field of implementation research has the potential to fill this knowledge gap and to address the barriers to the effective replication of evidence-based interventions in local settings. This article reviews the current understanding of the field of implementation research and discusses its association with other areas of health services research, clinical research, and quality management work. Opportunities for conducting implementation research are proposed, and future steps to develop the field are outlined.  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