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   48408篇
  免费   4967篇
  国内免费   1007篇
耳鼻咽喉   317篇
儿科学   940篇
妇产科学   591篇
基础医学   3539篇
口腔科学   1602篇
临床医学   4986篇
内科学   6096篇
皮肤病学   586篇
神经病学   3368篇
特种医学   1514篇
外国民族医学   3篇
外科学   4262篇
综合类   6256篇
现状与发展   5篇
一般理论   2篇
预防医学   8346篇
眼科学   650篇
药学   3670篇
  41篇
中国医学   4512篇
肿瘤学   3096篇
  2024年   169篇
  2023年   1032篇
  2022年   1544篇
  2021年   2032篇
  2020年   2001篇
  2019年   1909篇
  2018年   1883篇
  2017年   1842篇
  2016年   1684篇
  2015年   1509篇
  2014年   3412篇
  2013年   3409篇
  2012年   2785篇
  2011年   2970篇
  2010年   2328篇
  2009年   2270篇
  2008年   2554篇
  2007年   2519篇
  2006年   2266篇
  2005年   1945篇
  2004年   1612篇
  2003年   1503篇
  2002年   1177篇
  2001年   1092篇
  2000年   873篇
  1999年   763篇
  1998年   569篇
  1997年   596篇
  1996年   464篇
  1995年   483篇
  1994年   423篇
  1993年   321篇
  1992年   334篇
  1991年   299篇
  1990年   263篇
  1989年   249篇
  1988年   234篇
  1987年   188篇
  1986年   155篇
  1985年   138篇
  1984年   115篇
  1983年   77篇
  1982年   75篇
  1981年   63篇
  1980年   66篇
  1979年   36篇
  1978年   31篇
  1977年   27篇
  1976年   19篇
  1975年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Background Many people with learning disabilities (LD) show aggressive behaviour, but the extent of the problem and its associated factors and effects are unclear. Methods A cross‐sectional analysis was carried out using interview data from 3065 adults with LD on the Leicestershire LD Register. Physical aggression towards others was defined as carers reporting frequent (more than three times per week) and/or severe episodes. Individuals with and without aggression were compared using multiple logistic regression models for potential physical and psychological factors. Results Carers reported that 443 (14%) of adults were physically aggressive towards others. Men (P = 0.001), younger individuals (P < 0.001), people with more severe LD (P < 0.001) and those in institutional settings (P < 0.001) had a significantly higher prevalence of physical aggression. People with Down syndrome had a lower prevalence of physical aggression (P < 0.001). After adjustment, we found no relationship between aggression and the presence of epilepsy or autism. Among psychological factors, symptoms of frustration (P < 0.001) and mood swings (P < 0.001) were associated with higher levels of aggression. Failure to cope among carers was reported by 14% overall: 42% of people caring for adults with aggression said they were unable to cope compared with 10% of those caring for adults without aggression. Conclusions Physical aggression towards other people presents a significant challenge to carers of adults with LD. Further research is needed to identify aetiological factors with a view to finding effective interventions to reduce, and improve management of, this behaviour.  相似文献   
92.
Abstract Epilepsy in high-grade glioma patients is a major concern, mainly as regards indications to treatment and best choice; toxicities, and pharmocokinetic and pharmacodynamic interactions of drugs. All these generally unsolved problems complicate patients’ quality of life and interfere with the evaluation of response criteria in clinical trials. A prospective, multicentre data collection on 132 adult newly diagnosed, histologically proven glioblastomas from 9 Lombardy hospitals collected in the same database during a one-year period was recently published. From this database we report epidemiological and clinical characteristics in epilepsy-symptomatic (31%) glioblastoma patients vs. the group with other presenting symptoms (69%). We analyse demographic and clinico-radiological features, timing of onset and the course of seizures, and modalities of treatment in the two groups of patients. No statistically significant differences were observed between the two groups as regards age, site of lesion(s), extent of surgery and survival in relation to anticonvulsant treatment status or pharmacokinetic properties of drugs.  相似文献   
93.
Lung cancer mortality rates among United States and Japanese males were compared and related to smoking and dietary data. Mortality rates increased from 1950 to 1985 in both countries, but the absolute values are consistently lower in Japan (38.2 deaths/100,000 in 1985) than in the U.S. (72.2/100,000). The proportion of smokers is higher in Japan than in the U.S. since 1955. Japanese males start smoking considerably later than U.S. males, but smoke a higher quantity of cigarettes per day. Available information on inhalation practices and yield and type of cigarettes smoked showed no differences among the two countries large enough to account for the differences in mortality rates. Further data in this regard should he obtained. Dietary data show that fat consumption (as percentage of calories) is consistently higher in the U.S. than in Japan from 1950 (40% vs. 7.9%) through 1985 (43.5% vs. 24.5%). A linear relationship is observed between lung cancer mortality and fat intake. Our data support the hypothesis that dietary habits may modulate the carcinogenic effects of tobacco smoking.  相似文献   
94.
The results of the first 3 year' collaboration of the Italian Registry of Paediatric Chronic Peritoneal Dialysis (CPD) (1986–1988) are presented. This Registry acquired data on the majority of the paediatric patients treated with CPD in Italy, thus providing a national picture in a field where few nationwide surveys are available. Patients of less than 15 years of age at the start of dialysis were enrolled and clinical data collected until the age of 19 years. The number of nephrological paediatric centres participating in the Registry increased from 7 in 1986 to 11 in 1988. The total number of patients on CPD was 70 and the percentage of dialysed children treated with CPD ranged from 40.2% to 43.6%. Data on 89 peritoneal catheters were collected: during 1417 dialysis-months 70 catheter-related complications were observed (1:20.8 dialysis-months); actuarial catheter survival was 92.7% at 6 months, 84.8% at 1 year and 68.8% at 2 years. The incidence of peritonitis changed from 1 episode every 10.9 patient-months in 1986 to 1 every 19.8 in 1988. Abdominal hernias were the other main clinical complication observed. The survival of patients was 92.5% at 3 years, while the technique survival at the same time was 84%.  相似文献   
95.
对HCV血清标记阳性的静脉内毒瘤者进行半年和15个月随访,并调查影响转归的部分因素。结果显示,静脉内毒瘾者抗-HCV自然转阴率分别为11.0/和33.3%。单因素和多因素分析均提示转阴率以婚姻状况良好的已婚者较离婚者高、人均年收入高者较低者高,说明婚姻状况和人们的经济水平对毒瘾者抗-HCV转阴有一定的影响。  相似文献   
96.
用江西麦饭石水浸液喂养小鼠116只,自来水喂养39只,食物条件完全相同,一个月后,发现饮用江西麦饭石水浸液的小鼠体重增长和抗疲劳及耐缺氧能力均优于对照组。用麦饭石任氏液灌注离体蛙心后,心肌收缩力有明显增强。  相似文献   
97.
BACKGROUND: Susceptibility to asthma is known to involve genetic factors. Genome-wide screens have indicated that the chromosome 5q31-q34 region is linked to and/or associated with asthma. A new gene, named UGRP1 and reported by Niimi et al., encodes uteroglobin-related protein and is expressed in the lung and trachea. Niimi et al. showed the -112G/A polymorphism of the UGRP1 gene to be associated with asthma in a case-control study. OBJECTIVE: The objective of the present study was to replicate this association and confirm the possible role of the UGRP1-112G/A polymorphism in the aetiology of childhood asthma in a Japanese population. METHODS AND RESULTS: We conducted a transmission disequilibrium test (TDT) in 131 families identified through paediatric patients being treated for asthma. A case-control study was also carried out by comparing the probands and 137 unrelated non-atopic non-asthmatic Japanese children and 211 unrelated healthy Japanese adults. The -112G/A polymorphism was genotyped by the PCR-RFLP method. The TDT revealed that the -112A allele was not preferentially transmitted to asthma-affected children (P=0.85). Neither the presence of at least one A allele in an individual's genotype (sum of the G/A and A/A genotypes) nor the -112A allele was more prevalent among the asthma subjects than among the control subjects. CONCLUSION: Our findings indicate that the UGRP1-112G/A polymorphism does not play a substantial role in genetic predisposition to childhood asthma in this Japanese population.  相似文献   
98.
以液体稀释法比较了自制与进口十六烷基吡啶作用于4种口腔常见微生物的最低抑菌浓度和最低杀菌浓度的实验结果,经t检验证明两者间无显著差异,提示自制氯化十六烷基吡啶的药效质量可靠。并就控制接种菌量及杀菌机理等问题作了初步探讨。  相似文献   
99.
中药865液对创伤性出血止血效果的实验研究   总被引:1,自引:0,他引:1  
通过应用不同浓度的865液对家兔,家犬创伤性出血的止血效果实验观察、组织愈合的病理学检查和抑菌试验,结果表明:865液对创伤性出血有肯定的止血效果,对组织愈合无影响,同时还有明显的抑菌作用,为外伤性出血或术中手术野渗血觅得了新的止血措施。  相似文献   
100.
Anorectal function was evaluated in eight patients who had low anterior resection of the rectum with a low anastomotic line, using an EEA stapler, with determination of function based on periodic manometric studies and clinical symptoms. Immediately following surgery all patients suffered from frequent bowel actions and soiling. These symptoms improved with time and most patients could enjoy almost normal daily life by the sixth postoperative month. One month after surgery, anal canal resting pressure and maximum squeeze pressure were significantly reduced and rectoanal inhibitory reflex was absent; neither showed a distinct tendency to improve thereafter. Rectal sensation and reservoir capacity, which also were seriously impaired, recovered satisfactorily by the time of the six-month examination. This suggests that an improvement of clinical symptoms following this operation is dependent upon the recovery of reservoir capacity and sensation of the neorectum, and that this operative procedure is a functionally acceptable option for low rectal cancer.  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