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   31131篇
  免费   2252篇
  国内免费   527篇
耳鼻咽喉   486篇
儿科学   1166篇
妇产科学   489篇
基础医学   2459篇
口腔科学   1211篇
临床医学   3267篇
内科学   4925篇
皮肤病学   453篇
神经病学   8595篇
特种医学   539篇
外科学   1451篇
综合类   2350篇
现状与发展   3篇
一般理论   1篇
预防医学   3325篇
眼科学   215篇
药学   2113篇
  8篇
中国医学   536篇
肿瘤学   318篇
  2024年   127篇
  2023年   748篇
  2022年   1001篇
  2021年   1556篇
  2020年   1492篇
  2019年   1390篇
  2018年   1367篇
  2017年   1324篇
  2016年   1253篇
  2015年   1145篇
  2014年   1889篇
  2013年   2824篇
  2012年   1533篇
  2011年   1790篇
  2010年   1372篇
  2009年   1451篇
  2008年   1513篇
  2007年   1368篇
  2006年   1202篇
  2005年   957篇
  2004年   827篇
  2003年   854篇
  2002年   662篇
  2001年   476篇
  2000年   425篇
  1999年   390篇
  1998年   368篇
  1997年   322篇
  1996年   250篇
  1995年   243篇
  1994年   210篇
  1993年   186篇
  1992年   194篇
  1991年   142篇
  1990年   144篇
  1989年   81篇
  1988年   101篇
  1987年   96篇
  1986年   74篇
  1985年   112篇
  1984年   85篇
  1983年   60篇
  1982年   56篇
  1981年   47篇
  1980年   45篇
  1979年   43篇
  1978年   34篇
  1977年   31篇
  1976年   15篇
  1975年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Ziment  Irwin 《Lung》1990,168(1):168-176
Optimal control of chronic obstructive airway disorders is usually achieved with therapy based onβ 2-adrenoceptor agonist administration. Aerosols are highly effective, have few side effects, allow for fine adjustment of dosage to titrate symptoms, and result in reduction in hyperreactivity. Equivalent bronchodilating doses of oral agents cause side effects that limit acceptability. With oral agents, cardiohemodynamic disturbances are usually minor, while tremor and restlessness diminish with continued drug use. In chronic regimens, an aerosolβ 2-adrenergic agent should be chosen whose overall incidence of side effects is less than 5%, and an oral agent that produces no more than a 10% incidence of tremor. Suboptimal oral dosages in combination with maximal dosages ofβ 2-agonist aerosol, with or without other bronchodilator drugs, are advisable for chronic therapy. An optimal risk/benefit ratio with broxaterol therapy will probably be achieved by using an aerosol-oral combination. Thus, broxaterol, a newβ 2-agent, should be studied further to determine its value in chronic bronchospastic disorders.  相似文献   
992.

Objective

Eating disorders are associated with significant illness burden and costs, yet access to evidence-based care is limited. Greater use of programme-led and focused interventions that are less resource-intensive might be part of the solution to this demand-capacity mismatch.

Method

In October 2022, a group of predominantly UK-based clinical and academic researchers, charity representatives and people with lived experience convened to consider ways to improve access to, and efficacy of, programme-led and focused interventions for eating disorders in an attempt to bridge the demand-capacity gap.

Results

Several key recommendations were made across areas of research, policy, and practice. Of particular importance is the view that programme-led and focused interventions are suitable for a range of different eating disorder presentations across all ages, providing medical and psychiatric risk are closely monitored. The terminology used for these interventions should be carefully considered, so as not to imply that the treatment is suboptimal.

Conclusions

Programme-led and focused interventions are a viable option to close the demand-capacity gap for eating disorder treatment and are particularly needed for children and young people. Work is urgently needed across sectors to evaluate and implement such interventions as a clinical and research priority.  相似文献   
993.
To describe the clinical profile, management, maternal outcomes and factors associated with severe maternal outcome (SMO) in patients admitted for eclampsia.A retrospective cohort study was carried out. All women admitted to the Obstetric Intensive Care Unit (ICU) at Instituto de Medicina Integral Prof. Fernando Figueira (IMIP), Recife, Northeast of Brazil, from April 2012 to December 2019 were considered for inclusion and patients with the diagnosis of eclampsia were selected. Patients who, after reviewing their medical records, did not present a diagnosis of eclampsia were excluded from the study. Severe maternal outcome (SMO) was defined as all cases of near miss maternal mortality (MNM) plus all maternal deaths during the study period. The Risk Ratio (RR) and its 95% confidence interval (95% CI) were calculated as a measure of the relative risk. Multiple logistic regression analysis was performed to control confounding variables. The institute''s internal review board and the board waived the need of the informed consent.Among 284 patients with eclampsia admitted during the study period, 67 were classified as SMO (23.6%), 63 of whom had MNM (22.2%) and 5 died (1.8%). In the bivariate analysis, the following factors were associated with SMO: age 19 years or less (RR = 0.57 95% CI 0.37–0.89, P = .012), age 35 years or more (RR = 199 95% CI 1.18–3.34, P = .019), the presence of associated complications such as acute kidney injury (RR = 3.85 95% CI 2.69–5.51, P < .001), HELLP syndrome (RR = 1.81 95% CI 1.20–2.75, P = .005), puerperal hemorrhage (PPH) (RR = 2.15 95% CI 1.36–3.40, P = .003) and acute pulmonary edema (RR = 2.78 95% CI 1.55–4.96, P = .008). After hierarchical multiple logistic regression analysis, the factors that persisted associated with SMO were age less than or equal to 19 years (ORa = 0.46) and having had PPH (ORa = 3.33).Younger age was a protective factor for developing SMO, while those with PPH are more likely to have SMO.  相似文献   
994.
目的 探讨实施全民食盐加碘(USI)措施后,贵州省儿童甲状腺肿(甲肿)及其消长规律。方法 2001年4月采用点面结合的“典型调查”方法调查贵州省儿童的甲状腺肿情况,2003年10月采用群体追踪调查的方法,对2001年调查的同一人群开展甲肿消长情况的流行病学现况追踪调查。结果 2003年共有效追踪调查了1702名学生。其中在240例原检出Ⅰ度甲肿的学生中,139例转变为正常,转变率57.92%。15例转变Ⅱ度,转变率为6.25%。86例未改变,占35.83%。在28例原检出Ⅱ度甲肿的学生中,7例转为正常,2例转为I度,总体转变率42.86%。在追踪调查的1434名正常学生中,新发甲肿率为6.69%。结论 贵州省8~10岁儿童甲肿率逐年下降,但降幅非常缓慢,儿童甲肿多数会随时间推移自行减轻或恢复正常,只有少数会加重。  相似文献   
995.
It is now well-recognized that the activating JAK2(V617F) mutation occurs in the majority of patients with polycythemia vera (PV) and approximately half of those with either essential thrombocythemia (ET) or myelofibrosis with myeloid metaplasia (MMM). Here we analyzed JAK2(V617F) mutation in 137 Chinese patients with myeloproliferative disorders by allele-specific polymerase chain reaction (PCR). DNA was extracted from methanol/acetic acid-fixed cells that had been routinely prepared for cytogenetic analysis. A single point mutation (Val617Phe) was identified in JAK2 in 42 (73.7%) of 57 patients with PV, 40 (58.8%) of 68 with ET, and eight (66.7%) of 12 with MMM.  相似文献   
996.
997.
Anatomical variations in the dimensions of different brain structures have been correlated with clinical syndromes. This study on the parameters of normal and abnormal cavum septi pellucidi (CSP) can be of clinical significance. We obtained 479 brains from autopsied persons (310 males and 169 females, 377 normal or asymptomatic and 102 abnormal or symptomatic persons, aged 22-89 years) and observed that 110 brains (75 males and 35 females) had CSP. These cava were classified into two groups depending on the past medical histories of the autopsied person: 40 asymptomatic and 70 symptomatic cava. We have defined symptomatic cava as those in autopsied persons who had known past medical history of psychiatric or neurological disease. Asymptomatic cava were in autopsied persons who had no known past medical history of psychiatric or neurological disease. The CSP parameters (length, width, depth) of the symptomatic and asymptomatic groups were measured and were statistically analyzed. Analysis showed that the cava in the symptomatic group were significantly longer and wider. Discriminant function analysis was used to derive a mathematical formula to classify CSP into an asymptomatic or symptomatic group based on length and width measurements of the cavum.  相似文献   
998.
Deleterious variants in the same gene present in two or more families with overlapping clinical features provide convincing evidence of a disease–gene association; this can be a challenge in the study of ultrarare diseases. To facilitate the identification of additional families, several groups have created “matching” platforms. We describe four individuals from three unrelated families “matched” by GeneMatcher and MatchMakerExchange. Individuals had microcephaly, developmental delay, epilepsy, and recessive mutations in TRIT1. A single homozygous mutation in TRIT1 associated with similar features had previously been reported in one family. The identification of these individuals provides additional evidence to support TRIT1 as the disease‐causing gene and interprets the variants as “pathogenic.” TRIT1 functions to modify mitochondrial tRNAs and is necessary for protein translation. We show that dysfunctional TRIT1 results in decreased levels of select mitochondrial proteins. Our findings confirm the TRIT1 disease association and advance the phenotypic and molecular understanding of this disorder.  相似文献   
999.
OBJECTIVE: Many studies have reported that cognitive ability may be predictive of the functional outcome for patients with schizophrenia. However, no study has prospectively examined these aspects in schizophrenia and bipolar disorders simultaneously. The present study attempted to analyze if neurocognition and clinical status predicts the real-life functioning for patients with schizophrenia or bipolar I disorder, using a longitudinal design. METHOD: Forty-seven schizophrenic and 43 bipolar I outpatients were assessed twice with a neurocognitive battery (Executive Functions, Working Memory, Verbal Memory, Visual Memory, Visual-Motor Processing, Vigilance, Vocabulary and Motor Speed tasks), clinical scales (the Positive and Negative Symptom Scale, the Hamilton Rating Scale for Depression and the Clinician Administered Rating Scale for Mania) and functional outcome measures (the Global Assessment of Functioning Scale, the WHO's Disability Assessment Scale and occupational adaptation level) over a one-year follow-up period. The cognitive performance of the patients was compared, at baseline and one year later, with that of 25 healthy subjects. RESULTS: In schizophrenia patients, global functioning one year later was predicted by a composite neurocognitive score and three specific domain (verbal memory, motor speed, vocabulary). Symptoms appeared to explain less of the variance in functioning. In bipolar I patients, changes in the composite neurocognitive score over one year, deficits in the visual/motor processing domain, severity of symptoms (psychotic, excitatory and affective symptoms) and premorbid adjustment at the first assessment were the variables that better predicted functioning or disability changes over follow-up period. CONCLUSIONS: Although the relationships between cognition, symptoms and functional capacity differ for schizophrenia or bipolar I patients, neuropsychological performance seems to be a principal longitudinal predictor of functioning in both disorders. Baseline neurocognition and cognitive changes over 12 months predicted changes in functioning over the same period, but only in bipolar I patients. These cognitive domains could be potential neurocognitive endophenotypes (endophenocognitypes) with regard to bipolar I disorder.  相似文献   
1000.
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