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   1199篇
  免费   136篇
  国内免费   3篇
耳鼻咽喉   11篇
儿科学   80篇
妇产科学   31篇
基础医学   199篇
口腔科学   31篇
临床医学   218篇
内科学   218篇
皮肤病学   36篇
神经病学   159篇
特种医学   20篇
外科学   82篇
综合类   4篇
预防医学   88篇
眼科学   20篇
药学   77篇
肿瘤学   64篇
  2023年   8篇
  2022年   11篇
  2021年   12篇
  2020年   26篇
  2019年   33篇
  2018年   32篇
  2017年   30篇
  2016年   26篇
  2015年   40篇
  2014年   37篇
  2013年   60篇
  2012年   98篇
  2011年   66篇
  2010年   54篇
  2009年   49篇
  2008年   79篇
  2007年   67篇
  2006年   57篇
  2005年   70篇
  2004年   55篇
  2003年   64篇
  2002年   51篇
  2001年   30篇
  2000年   31篇
  1999年   30篇
  1998年   12篇
  1997年   19篇
  1996年   9篇
  1995年   10篇
  1994年   12篇
  1993年   18篇
  1992年   21篇
  1991年   22篇
  1990年   11篇
  1989年   11篇
  1988年   11篇
  1987年   16篇
  1986年   9篇
  1985年   5篇
  1984年   3篇
  1983年   3篇
  1982年   8篇
  1981年   3篇
  1980年   2篇
  1979年   7篇
  1978年   3篇
  1977年   2篇
  1973年   1篇
  1972年   1篇
  1970年   1篇
排序方式: 共有1338条查询结果,搜索用时 15 毫秒
1.
BACKGROUND: Airway inflammation is a characteristic feature of bronchial asthma. Previous studies have shown an increased local inflammatory activity in the airway mucosa of asthma patients. OBJECTIVES: To analyze the association of asthma with three sensitive markers of systemic inflammation, C-reactive protein, serum amyloid-A (SAA), and plasma fibrinogen. METHODS: A cross-sectional, population-based study including 1,513 Finnish men aged 45 to 74 years, who participated in a chronic disease risk factor survey in 1997. Of the participating men, 97 were classified as asthma patients. The odds ratios of asthma were analyzed by quartile of each inflammation marker. RESULTS: In logistic regression models the age-adjusted odds ratios (second, third, and fourth quartile as compared with the first quartile) of asthma increased gradually with increasing quartile of C-reactive protein (1.28, 1.19, 1.96, P for trend = 0.039), SAA (1.20, 3.00, 3.49, P for trend < 0.001), and fibrinogen (1.22, 1.79, 3.16, P for trend < 0.001). The associations were independent of smoking. Further adjustment for waist-to-hip ratio, a marker of central obesity, and symptoms of chronic bronchitis weakened the observed association, but the increasing trend in the association of SAA and fibrinogen with asthma remained highly significant. CONCLUSIONS: Sensitive markers of systemic inflammation, particularly SAA and fibrinogen, were positively and significantly associated with asthma prevalence. These findings support the hypothesis that not only local, but also systemic, inflammation exist in bronchial asthma.  相似文献   
2.
Samples from 96 children with acute respiratory infection were obtained simultaneously with nasal, nasopharyngeal, and oropharyngeal swabs and by nasopharyngeal aspiration and were cultured on chocolate and blood agar plates. The rates of isolation of Streptococcus pneumoniae and Haemophilus influenzae detected by the four sampling methods were compared. Nasopharyngeal aspirates were optimal for the detection of both S. pneumoniae (isolation rate, 33%) and H. influenzae (isolation rate, 31%). When a nasopharyngeal aspirate is not available, such as for healthy children or children with no obtainable secretions, the nasopharyngeal swab seems optimal for the detection of both S. pneumoniae and H. influenzae among children younger than 13 months of age. Among older children, similarly, the nasopharyngeal swab seems optimal for the detection of S. pneumoniae; however, for H. influenzae, the oropharyngeal swab seems optimal.  相似文献   
3.
Two sampling techniques, nasal swabbing and oropharyngeal swabbing, for detection of the upper respiratory tract carriage of Streptococcus pneumoniae and Haemophilus influenzae were studied prospectively with 296 healthy Filipino infants at various ages: 6 to 8, 10 to 12, 14 to 17, 18 to 22, 32 to 39, and 46 to 65 weeks. In all age groups S. pneumoniae was isolated significantly more often (P < 0.0001) from the nasal site than from the oropharyngeal site. H. influenzae was found equally often at both sites.  相似文献   
4.
Nineteen patients with 49 symptomatic non-neoplastic non-parasitic simple hepatic cysts were subjected to ultrasonographically guided percutaneous aspiration and temporary injection of 99% ethanol into the cyst. Small cysts were treated twice, the large ones three times at the same sitting. The volume of alcohol per injection varied from 20 to 100 ml, depending on the size of the cyst. A cure was usually achieved with one ethanol sclerotherapy treatment. Only minor side effects such as transient pain and temperature elevation occurred. Forty-seven of the 49 cysts could be treated adequately, and did not recur during a follow-up period af 12–40 months. The results indicate that aspiration an and ethanol sclerotherapy is the treatment of choice in patients with symptomatic non-neoplastic simple hepatic cysts or polycystic liver disease. Correspondence to: A. Leinonen  相似文献   
5.
The presence of human papillomavirus (HPV) DNA in cervical and vaginal scrapes was analyzed by the AffiProbe HPV test kit (Orion Corp., Orion Pharmaceutica, Helsinki, Finland), which is a 1-day solution hybridization test for HPV type 6/11, 16, or 18. The AffiProbe test was compared with a commercially available dot blot test (ViraPap and ViraType tests; Life Technologies Inc., Gaithersburg, Md.). The study group consisted of 178 patients seen in a gynecological outpatient clinic. Altogether, 64 specimens (36 cervical and 28 vaginal scrapes) from 49 patients were positive by the AffiProbe test. Concurrently collected cervical scrapes from 174 patients were available for the reference test, which yielded 27 positive results for HPV type 6/11 or 16/18 and 25 positive results for HPV type 31/33/35. Agreement as to the presence of HPV type 6/11, 16, or 18 by the two tests was reached in 85% of the specimens. Eleven cervical specimens were positive by the AffiProbe test only, and nine cervical specimens were positive by the ViraType test only. Independent evidence obtained by the polymerase chain reaction, repeat examination, or the concurrent presence of HPV DNA in vaginal or vulval epithelium supported the AffiProbe and the ViraType test results for 6 of the 11 and 6 of the 9 specimens with discrepant results, respectively. Thus, the DNA tests had similar sensitivities for HPV type 6/11, 16, and 18 DNAs, but the results were obtained within 1 day by the AffiProbe test, whereas results for the ViraPap and ViraType analyses required from 4 days to 2 weeks.  相似文献   
6.
Chlamydia pneumoniae is an obligate intracellular pathogen with a tendency to cause persistent infections that has been associated with many chronic conditions such as asthma and coronary artery disease. However, its immunopathogenic mechanisms are poorly understood. When aiming to study the impact of C. pneumoniae infection on host cell apoptosis, we found that epithelial infected (HL) cells and macrophages (U937-line) were resistant to staurosporine and tumour necrosis factor (TNF)-alpha-induced physiological apoptosis 48, 72 or 120 h post-infection, as determined by flow cytometry, DNA fragmentation assay and fluorescence microscopy. The antiapoptotic influence was observed even at a late stage of the chlamydial life cycle and was dependent on the chlamydial protein synthesis. The mechanisms involved blockage of mitochondrial cytochrome c release and caspase 3 activation. We also found that during a persistent C. pneumoniae infection induced in vitro by penicillin treatment of cell cultures, the inhibition of apoptosis was extended for up to 120 h of follow-up post-infection and was restricted to the cells carrying chlamydial inclusions. Our findings suggest that inhibition of apoptosis may be one of the pathogenetic mechanisms by which C. pneumoniae infection can mediate the development of chronic diseases.  相似文献   
7.
8.
It is not known how well nasopharyngeal swab culture represents pneumococcal carriage status. We tested this by comparing swab culture to quantitative culture and quantitative PCR of mucosal tissue in a rat model of pneumococcal carriage. Quantitative culture and quantitative PCR identified significantly more carriers compared to swab culture (differences 15% and 33%, 95% CI 1-28% and 16-47%, p=0.04 and 0.001, respectively). The sensitivity and specificity of swab culture was 75/92% and 63/100% compared to quantitative tissue culture and quantitative PCR, respectively. The quantitative estimates of culture and PCR were very similar (Pearson correlation coefficient 0.79, p<0.001). In conclusion, even a well-controlled swab sampling markedly underestimates pneumococcal carriage rate, and simultaneous use of quantitative culture and PCR increases the number of positive samples by about one third.  相似文献   
9.
We aimed to compare the antidepressant and anxiolytic effects, tolerability and effects on quality of life of mirtazapine and citalopram in a randomized, double-blind, multicentre, 8-week study. Patients with a Major Depressive Episode (DSM-IV) and a baseline score of > or = 22 on the Montgomery-Asberg Depression Rating Scale (MADRS) were randomized to 8 weeks treatment with either mirtazapine (n = 137, 15-60 mg/day) or citalopram (n = 133, 20-60 mg/day). Efficacy was evaluated by the MADRS, Hamilton Anxiety Scale (HAM-A), Clinical Global Impression scales (CGI), the Leeds Sleep Evaluation Questionnaire (LSEQ) and Quality of Life Enjoyment and Satisfaction Questionnaire (QLESQ). The efficacy analyses were performed on the Intent-To-Treat Group using the Last Observation Carried Forward method. Vital signs and laboratory variables are measured and adverse events recorded at each weekly visit. The magnitude of reduction from baseline in group mean MADRS scores was large in both groups, reaching after 8 weeks of treatment mean scores of 9.1 in the mirtazapine group and 8.9 in the citalopram group. Both treatments also resulted in a substantial improvement in anxiety symptoms, sleep disturbances and quality of life, and high percentage of responders. However, at day 14, statistically significantly larger magnitudes of change favouring mirtazapine were present in the group mean MADRS, HAM-A and CGI-Severity of illness and Quality of life scores. A difference of 2.3 points on MADRS favouring mirtazapine is considered indicative for a clinically relevant superiority between two proven antidepressants. Mirtazapine treatment was also related to faster improvement of sleep, quality of sleep and improved alertness following awakening, as shown by statistically significant differences on the self-rating LSEQ at various time points. There were no differences between two treatment groups on self-rating QLSEQ. Both drugs were well tolerated, with a low number of patients in either group prematurely terminating the study due to adverse events (mirtazapine: 3.6%, citalopram, 3.0%). Sweating and nausea were statistically significantly more frequent in the citalopram group and increased appetite and complaints of weight increase in the mirtazapine group. There were no clinically relevant changes in laboratory parameters and vital sign variables with either treatment, except for clinically relevant increase in body weight, occurring more frequently in mirtazapine patients. In this study, mirtazapine and citalopram were equally effective in reducing symptoms of depression and anxiety, and well tolerated. However, mirtazapine was significantly more effective than citalopram after 2 weeks of treatment on the MADRS, HAM-A and CGI Severity of illness and Quality of life scales. This finding, consistently present at all major efficacy variables, suggests potentially faster onset of efficacy of mirtazapine over citalopram.  相似文献   
10.
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