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   737篇
  免费   55篇
  国内免费   14篇
儿科学   55篇
妇产科学   4篇
基础医学   98篇
口腔科学   10篇
临床医学   88篇
内科学   152篇
皮肤病学   29篇
神经病学   41篇
特种医学   87篇
外科学   70篇
综合类   7篇
预防医学   92篇
眼科学   4篇
药学   27篇
  2篇
中国医学   2篇
肿瘤学   38篇
  2023年   7篇
  2020年   9篇
  2019年   10篇
  2018年   13篇
  2017年   14篇
  2016年   11篇
  2015年   13篇
  2014年   20篇
  2013年   24篇
  2012年   31篇
  2011年   15篇
  2010年   25篇
  2009年   28篇
  2008年   28篇
  2007年   17篇
  2006年   22篇
  2005年   15篇
  2004年   18篇
  2003年   22篇
  2002年   14篇
  2001年   21篇
  2000年   16篇
  1999年   20篇
  1998年   21篇
  1997年   26篇
  1996年   17篇
  1995年   16篇
  1994年   18篇
  1993年   11篇
  1992年   12篇
  1991年   7篇
  1990年   13篇
  1989年   21篇
  1988年   7篇
  1987年   17篇
  1986年   16篇
  1985年   18篇
  1984年   7篇
  1983年   11篇
  1980年   10篇
  1979年   11篇
  1978年   12篇
  1976年   10篇
  1975年   9篇
  1974年   10篇
  1973年   12篇
  1972年   10篇
  1970年   12篇
  1968年   11篇
  1966年   9篇
排序方式: 共有806条查询结果,搜索用时 15 毫秒
31.
32.
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   
33.
BACKGROUND : The effects of salt intake on renal regulation have been investigated for decades. To find new pathways and to demonstrate the utility of oligonucleotide expression arrays, we studied whole kidneys. METHODS : Eight Sprague-Dawley rats were divided into two groups. One group received a 6% salt (by weight) diet, while the other group received a 0.3%, otherwise identical, salt diet for 7 days. The rats were sacrificed after 7 days and the left kidney was subjected to RNA extraction. Oligonucleotide expression arrays (Affymetrix) were used to determine downregulation and upregulation, comparing high with low salt intake. Four rats from each group were studied separately. RESULTS : The experiments were reproducible. Thirty genes were downregulated with the high-salt diet, while 35 genes were upregulated. The renin gene, beta-2 glycoprotein-1, retinol binding protein, annexin VI, and the PTP2C protein tyrosine phosphatase were among the downregulated genes. The angiotensin II receptor type 1B receptor, HMG-CoA reductase, B7 antigen, and the rat calcium channel beta subunit III were among the upregulated genes. Differentially regulated were the p55 subunit (upregulated) and the p50 subunit (downregulated) of the phosphatidyl inositol 3-kinase enzyme complex. We verified our results by selecting a high-salt downregulated gene (renin) and an upregulated gene (B7 antigen) and subjecting these genes to real-time polymerase chain reaction. The results were consistent. CONCLUSION : Oligonucleotide expression arrays can detect novel genes encoding for proteins not generally associated with responses to varied salt intake. Experiments of this nature have substantial limitations and require detailed verification. However, overall, the utility is promising.  相似文献   
34.
BACKGROUND. Late life onset schizophrenia (sometimes termed "late paraphrenia") has been theorized to be due to neuro-degenerative processes affecting individuals with latent vulnerability to schizophrenia. However, neuro-imaging studies using computed tomography (CT) and magnetic resonance imaging (MRI) investigating possible degenerative anatomic correlates (atrophy, white matter disease, and strokes) to late onset psychoses have yielded conflicting findings. The variation in these findings may be due to differences in study design, case ascertainment, and measurement methods. OBJECTIVE. The present study compares a continuous measure of total volume of white matter hyperintensities (WMHs) in age, race, and gender-ratio matched groups of late-onset schizophrenic, elderly, early-onset schizophrenic and control subjects. METHOD. Our method of WMH measurement yielded an explicit volume and is an alternative to frequently used ordinal measures. RESULTS. We found no significant differences in the WMH volumes between these three groups. This finding is consistent with a prior study (Symonds et al., 1997. J Neuropsychiat Clin Neurosci 9: 251 - 258), that used ordinal measures.  相似文献   
35.
The objective of this study was to investigate EEG frequency profiles (topographic distribution of spectral power data) in well-defined idiopathic generalised epilepsy (IGE) syndromes: juvenile absence epilepsy (JAE), juvenile myoclonic epilepsy (JME), epilepsy with grand mal seizures on awakening (EGMA), and in the unified 'common IGE' (CIGE) group of these patients. Methods: Absolute and relative (percent) power values were computed from waking EEG activity by Fast Fourier Transform (FFT). Each patient group was compared to an age-matched group of healthy control persons. Results: There was a general tendency for diffuse (absolute and relative) delta-theta-alpha power excess and relative beta power deficit in all IGE groups as compared to controls. Statistically significant (P相似文献   
36.
Overheating may cause terminal apnoea and cot death. Rectal temperature and breathing patterns were examined in normal infants at home during the first 6 months of life. Twenty one infants had continuous overnight rectal temperature and breathing recordings for 429 nights (mean 20.4 nights, range 7-30) spaced over the first six months of life. Periods when breathing was 'regular' were directly marked on single night records. Sleep state was determined from respiratory variables. 'Regular' breathing was a reliable marker of 'quiet' sleep (specificity 93%). The duration of 'quiet' sleep increased from 6 to 22 minutes from two weeks to three months of age and then remained static, as did the proportion of sleep spent in the quiet phase (9% to 34%). Rectal temperature fell during 66% of quiet sleep and usually rose during rapid eye movement (REM) sleep. The drop in rectal temperature was maximal at the start of quiet sleep, whereas the maximum rise during REM sleep was reached after 10 to 15 minutes. Oscillations in rectal temperature are associated with changes in sleep and breathing state. The maturation of rectal temperature patterns during the first six months of life are closely related to a maturation of sleep state and breathing patterns.  相似文献   
37.
38.
39.
40.
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