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   503篇
  免费   53篇
  国内免费   4篇
儿科学   31篇
妇产科学   1篇
基础医学   91篇
口腔科学   8篇
临床医学   65篇
内科学   103篇
皮肤病学   9篇
神经病学   10篇
特种医学   79篇
外科学   42篇
综合类   8篇
预防医学   67篇
眼科学   3篇
药学   22篇
  2篇
肿瘤学   19篇
  2023年   4篇
  2020年   5篇
  2019年   6篇
  2018年   8篇
  2017年   6篇
  2016年   7篇
  2015年   10篇
  2014年   11篇
  2013年   38篇
  2012年   16篇
  2011年   11篇
  2010年   14篇
  2009年   23篇
  2008年   14篇
  2007年   12篇
  2006年   14篇
  2005年   10篇
  2004年   18篇
  2003年   17篇
  2002年   10篇
  2001年   14篇
  2000年   11篇
  1999年   16篇
  1998年   20篇
  1997年   23篇
  1996年   21篇
  1995年   19篇
  1994年   18篇
  1993年   12篇
  1992年   6篇
  1991年   11篇
  1990年   11篇
  1989年   13篇
  1988年   8篇
  1987年   12篇
  1986年   9篇
  1985年   10篇
  1984年   4篇
  1983年   10篇
  1982年   5篇
  1980年   5篇
  1979年   7篇
  1978年   8篇
  1977年   5篇
  1976年   8篇
  1975年   4篇
  1974年   3篇
  1971年   2篇
  1967年   2篇
  1958年   2篇
排序方式: 共有560条查询结果,搜索用时 15 毫秒
1.
Clinical aspects of pelvic inflammatory disease   总被引:2,自引:0,他引:2  
Pelvic inflammatory disease (PID) is a common and poorly managed condition. Untreated or inadequately treated, it leads to tubal infertility, ectopic pregnancy and chronic pelvic pain. Diagnostic difficulties are compounded by the wide variety of clinical presentations and the insensitivity and poor specificity of laboratory tests. Better recognition of mild and atypical disease needs a high index of suspicion whenever young, sexually active women present with gynaecological symptoms. Laparoscopy supplemented by microbiological tests and fimbrial minibiopsy should be regarded as the diagnostic 'gold standard' for research studies; new studies are required to identify techniques which might reduce under- and over-diagnosis. Early treatment reduces the risk of an adverse effect on fertility. Any therapeutic regimen selected should be effective against the common aetiological agents Chlamydia trachomatis, Neisseria gonorrhoeae, genital mycoplasmas and aerobic and anaerobic bacteria. Since at least 60% of cases of PID can be attributed to infection with a sexually transmitted organism, partner notification forms an essential part of management.   相似文献   
2.
Smoking and raven IQ   总被引:1,自引:0,他引:1  
Nicotine has recently been shown to enhance measures of information processing speed including the decision time (DT) component of simple and choice reaction time and the string length measure of evoked potential waveform complexity. Both (DT and string length) have been previously demonstrated to correlate with performance on standard intelligence tests (IQ). We therefore hypothesised that nicotine is acting to improve intellectual performance on the elementary information processing correlates of IQ. In the current experiment we tested this hypothesis using the Raven Advanced Progressive Matrices (APM) test. APM scores were significantly higher in the smoking session compared to the non-smoking session, suggesting that nicotine acts to enhance physiological processes underlying performance on intellectual tasks.  相似文献   
3.
Screening for early ovarian cancer   总被引:5,自引:0,他引:5  
Taylor  KJ; Schwartz  PE 《Radiology》1994,192(1):1
  相似文献   
4.
BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a major health problem with an estimated prevalence of 10-15% among smokers. The incidence of moderate COPD, as defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD), is largely unknown. AIM: To determine the cumulative incidence of moderate COPD (forced expiratory volume in 1 second/forced vital capacity ratio [FEV1/FVC] <0.7 and FEV1 <80% predicted) and its association with patient characteristics in a cohort of male smokers. DESIGN: Prospective cohort study. SETTING: The city of IJsselstein, a small town in the Netherlands. METHOD: Smokers aged 40-65 years who were registered with local GPs, participated in a study to identify undetected COPD. Baseline measurements were taken in 1998 of 399 smokers with normal spirometry (n = 292) or mild COPD (FEV1/FVC <0.7 and FEV1 >or=80% predicted, n = 107) and follow-up measurements were conducted in 2003. RESULTS: After a mean follow-up of 5.2 years, 33 participants developed moderate COPD (GOLD II). This showed an estimated cumulative incidence of 8.3% (95% CI = 5.8 to 11.4) and a mean annual incidence of 1.6%. No participant developed severe airflow obstruction. The risk of developing moderate COPD in smokers with baseline mild COPD (GOLD I) was five times higher than in those with baseline normal spirometry (one in five versus one in 25). CONCLUSIONS: In a cohort of middle-aged male smokers, the estimated cumulative incidence of moderate COPD (GOLD II) over 5 years was relatively high (8.3%). Age, childhood smoking, cough, and one or more GP contacts for lower respiratory tract problems were independently associated with incident moderate COPD.  相似文献   
5.
BACKGROUND: Chest radiography (CXR) is frequently performed in Western societies. There is insufficient knowledge of its diagnostic value in terms of changes in patient management decisions in primary care. AIM: To assess the influence of CXR on patient management in general practice. DESIGN OF STUDY: Prospective cohort study. SETTING: Seventy-eight GPs and three general hospitals in the Netherlands. METHOD: Patients (n = 792) aged > or =18 years referred by their GPs for CXR were included. The main outcome was change in patient management assessed by means of questionnaires filled in by GPs before and after CXR. RESULTS: Mean age of the patients was 57.3+/-16.2 years and 53% were male. Clinically relevant abnormalities were found in 24% of the CXRs. Patient management changed in 60% of the patients following CXR. Main changes included: fewer referrals to a medical specialist (from 26 to 12%); reduction in initiation or change in therapy (from 24 to 15%); and more frequent reassurance (from 25 to 46%). However, this reassurance was not perceived as such in a quarter of these patients. A change in patient management occurred significantly more frequently in patients with complaints of cough (67%), those who exhibited abnormalities during physical examination (69%), or those with a suspected diagnosis of pneumonia (68%). CONCLUSION: Patient management by the GP changed in 60% of patients following CXR. CXR substantially reduced the number of referrals and initiation or change in therapy, and more patients were reassured by their GP. Thus, CXR is an important diagnostic tool for GPs and seems a cost-effective diagnostic test.  相似文献   
6.
7.
Enveloped whole virions and nucleocapsids of human herpesvirus 6 (HHV-6) strain Z29 were purified from supernatant fluids of infected human cord blood lymphocytes by filtration through polyvinylpyrrolidone-treated filters, banding on a Nycondenz step gradient, and centrifugation through two successive continuous sucrose gradients. More than 20 proteins ranging in molecular weight from less than 30,000 to more than 200,000 were identified in preparations of purified whole virions labeled with [35S]methionine and [35S]cysteine. Immunogenic virion proteins of HHV-6 were identified in immunoblot assays with human immune sera, immune sera generated from mice immunized with purified whole virions or purified nucleocapsids, and a monoclonal antibody generated from a mouse immunized with purified nucleocapsids. The sera and the monoclonal antibody reacted strongly with a 101-kilodalton protein in the immunoblots, suggesting that the protein is a component of the nucleocapsid. Human sera lacking HHV-6-specific antibodies and seropositive for one or more of the other human herpesviruses failed to react with this protein, indicating that it is a specific serologic marker for HHV-6 infection.  相似文献   
8.
Hegedus  V; Poulsen  PE; Reichardt  J 《Radiology》1978,126(1):29-34
A study of 11 patients with "double pylorus" revealed that a second channel between the gastric antrum and the duodenal bulb is the result of ulcer penetration. The fistula can be a sign of spontaneous recovery from ulcerative disease; the fistula occurred in conjunction with clinical improvement in the majority of the patients. The advantages of radiological vs. endoscopic diagnostic procedures are discussed.  相似文献   
9.
Cross sectional studies have reported impaired growth in children with atopic dermatitis. If this growth impairment is irreversible, it would be expected to adversely influence final height attainment. The standing heights and other anthropometric parameters were assessed in 35 adults with onset of atopic dermatitis before 5 years of age and a control group of 35 adults with adult onset contact dermatitis or psoriasis. There was no significant difference in the standing height SD score, mid-parental height SD score, sitting height SD score, subischial leg length SD score, nor body mass index between the atopic dermatitis and control groups. The standing height SD score was not significantly different among: (a) patients with atopic dermatitis affecting less than 50% of their body surface area and those with greater than 50% affected; (b) patients using the four different potency topical corticosteroids; and (c) patients with atopic dermatitis without asthma and those with coexisting asthma. It is concluded that short stature is not a feature of our group of adult patients with onset of atopic dermatitis before 5 years of age, continuing into adulthood, and severe enough to require specialist care. This suggests that if growth impairment occurs in childhood, it is likely to be temporary and reversible.  相似文献   
10.
Undernutrition, a multifactorial phenomenon, has severe consequences. A study was conducted in Syria to compare nutritional differences in children from three rural livelihood groups: a “barley-livestock” group in the southeast (Khanasser), and an “olive/fruit tree” group and an “irrigation” group in the northwest of Aleppo province (Afrin). An anthropometric assessment was conducted on 541 rural children from 207 rural households and 199 urban children (2-10 years) from a middle income urban group. Comparisons were made with the 1978 NCHS/WHO (National Center for Health Statistics/ World Health Organization) international growth reference (WHO, 1995) and a -2 SD Z-score was used as a cut-off. Prevalence rates and mean Z-scores were calculated and independent sample t-tests used to compare totals and age-group disaggregated children (both boys and girls). Total stunting prevalence was highest in the barley-livestock group (23%) and lowest in the irrigation group (12.5%). Girls in the barley-livestock group displayed the highest rates of stunting (28.3%), followed by the boys (22%) and the girls (21.08%) in the olive/fruit tree group. The prevalence of underweight children was highest in the barley-livestock and olive/fruit tree livelihood groups (14.29% and 13.25%, respectively). Wasting rates were very low. The rates of stunting and underweight were higher in the barley-livestock and olive/fruit tree groups, as compared with the country-level estimates of 20.8 percent and 12.9 percent respectively, in children under five. A comparison of rates and mean scores indicates that, amongst rural groups, there was considerable variation: the barley-livestock and olive/fruit tree group, belonging to drier and poorer areas, exhibited higher rates and lower mean scores.  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