全文获取类型
收费全文 | 3092篇 |
免费 | 237篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 80篇 |
儿科学 | 88篇 |
妇产科学 | 50篇 |
基础医学 | 378篇 |
口腔科学 | 31篇 |
临床医学 | 395篇 |
内科学 | 627篇 |
皮肤病学 | 104篇 |
神经病学 | 329篇 |
特种医学 | 203篇 |
外科学 | 329篇 |
综合类 | 122篇 |
一般理论 | 1篇 |
预防医学 | 307篇 |
眼科学 | 44篇 |
药学 | 121篇 |
中国医学 | 1篇 |
肿瘤学 | 132篇 |
出版年
2023年 | 24篇 |
2022年 | 29篇 |
2021年 | 66篇 |
2020年 | 40篇 |
2019年 | 52篇 |
2018年 | 73篇 |
2017年 | 53篇 |
2016年 | 67篇 |
2015年 | 60篇 |
2014年 | 101篇 |
2013年 | 138篇 |
2012年 | 128篇 |
2011年 | 140篇 |
2010年 | 123篇 |
2009年 | 123篇 |
2008年 | 140篇 |
2007年 | 115篇 |
2006年 | 131篇 |
2005年 | 119篇 |
2004年 | 112篇 |
2003年 | 114篇 |
2002年 | 102篇 |
2001年 | 91篇 |
2000年 | 68篇 |
1999年 | 70篇 |
1998年 | 57篇 |
1997年 | 62篇 |
1996年 | 54篇 |
1995年 | 45篇 |
1994年 | 42篇 |
1993年 | 43篇 |
1992年 | 55篇 |
1991年 | 40篇 |
1990年 | 60篇 |
1989年 | 50篇 |
1988年 | 42篇 |
1987年 | 61篇 |
1986年 | 49篇 |
1985年 | 55篇 |
1984年 | 37篇 |
1983年 | 21篇 |
1982年 | 22篇 |
1981年 | 21篇 |
1980年 | 15篇 |
1979年 | 23篇 |
1978年 | 15篇 |
1975年 | 17篇 |
1974年 | 19篇 |
1973年 | 20篇 |
1971年 | 19篇 |
排序方式: 共有3342条查询结果,搜索用时 15 毫秒
31.
Heel pain in children is common, and its evaluation is challenging. Medical history and physical examination may be unrevealing owing to children's limited communication skills. Often, advanced laboratory and imaging studies are required to make an accurate diagnosis. The most common causes of heel pain in children are apophysitis, enthesopathy, and overuse syndromes such as tendinitis. Juvenile rheumatoid arthritis is relatively uncommon. In very active children, occult fractures must also be evaluated. Pain unrelated to activity may indicate tumors, infection, or congenital problems. In general, heel pain in children is treated nonoperatively. For fractures in particular, children are less likely than adults to receive surgical treatment. 相似文献
32.
S Shea C R Isasi S Couch T J Starc R P Tracy R Deckelbaum P Talmud L Berglund S E Humphries 《American journal of epidemiology》1999,150(7):737-746
Higher plasma fibrinogen levels are associated with increased risk of myocardial infarction in adults, but little is known about factors that influence fibrinogen levels in childhood. The authors examined the associations of measures of obesity, presence of the (G-455-->A) allele in the beta-fibrinogen promoter gene, and family history of early onset of ischemic heart disease with plasma fibrinogen levels in children. Children (n = 299) were recruited during 1994-1997 from 276 families living in a racially mixed area of New York City. The mean age of the study children was 9.9 years; 79% were Hispanic. The frequency of the (G-455-->A) allele was lower in Hispanics than in non-Hispanic Whites (15.5% vs. 28.3% in children (p < 0.01) and 13.9% vs. 28.3% in parents (p < 0.001)). Graded relations of children's plasma fibrinogen levels were found with tertiles of body mass index (weight (kg)/height (m)2) and sum of skinfolds (tests for linear trend: p < 0.001). Plasma fibrinogen levels in the children were not related to race/ethnicity, presence of the (G-455-->A) allele, or family history. Multiple linear regression analyses adjusting plasma fibrinogen levels for age, sex, race/ethnicity, the (G-455-->A) allele, and family history of early onset of heart disease showed a significant association with either body mass index or sum of skinfolds (p < 0.001 for both models) but not with the other variables. 相似文献
33.
We studied physiological and sensory effects of left cervical vagal stimulation in six adult patients receiving this stimulation as adjunctive therapy for intractable epilepsy. Stimulus strength varied among subjects from 0.1 to 2.1 microCoulomb (microC) per pulse, delivered in trains of 30-45 s at frequencies from 20 to 30 Hz; these stimulation parameters were standard in a North American study. The stimulation produced no systematic changes in ECG, arterial pressure, breathing frequency tidal volume or end-expiratory volume. Five subjects experienced hoarseness during stimulation. Three subjects with high stimulus strength (0.9-2.1 microC) recalled shortness of breath during stimulation when exercising; these sensations were seldom present during stimulation at rest. No subjects reported the thoracic burning sensation or cough previously reported with chemical stimulation of pulmonary C fibers. Four of six subjects (all those receiving stimuli at or above 0.6 microC) experienced a substantial reduction in monthly seizure occurrence at the settings used in our studies. Although animal models of epilepsy suggest that C fibers are the most important fibers mediating the anti-seizure effect of vagal stimulation, our present findings suggest that the therapeutic stimulus activated A fibers (evidenced by laryngeal effects) but was not strong enough to activate B or C fibers. 相似文献
34.
Co-occurrence of mood and personality disorders: a report from the Collaborative Longitudinal Personality Disorders Study (CLPS) 总被引:1,自引:0,他引:1
Skodol AE Stout RL McGlashan TH Grilo CM Gunderson JG Shea MT Morey LC Zanarini MC Dyck IR Oldham JM 《Depression and anxiety》1999,10(4):175-182
The purpose of this study was to examine the relationship of subtypes and particular clinical features of mood disorders to co-occurrence with specific personality disorders. Five hundred and seventy-one subjects recruited for the Collaborative Longitudinal Personality Disorders Study (CLPS) were assessed with the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) and the Diagnostic Interview for DSM-IV Personality Disorders (DIPD-IV). Percent co-occurrence rates for current and lifetime mood disorders with personality disorders were calculated. Logistic regression analyses examined the effects of clinical characteristics of depressive disorders (e.g., age at onset, recurrence, symptom severity, double depression, and atypical features) on personality disorder co-occurrence. In comparison with other DSM-IV personality disorders, avoidant, borderline, and dependent personality disorders (PDs) were most specifically associated with mood disorders, particularly depressive disorders. Severity and recurrence of major depressive disorder and comorbid dysthymic disorder predicted co-occurrence with borderline and to a lesser extent research criteria depressive personality disorders. The results are consistent with the view that a mood disorder with an insidious onset and recurrence, chronicity, and progression in severity leads to a personality disorder diagnosis in young adults. 相似文献
35.
Joseph P. Eder Anthony D. Elias Lois Ayash Catherine A. Wheeler Thomas C. Shea Lowell E. Schnipper Emil Frei III Karen H. Antman 《Cancer chemotherapy and pharmacology》1991,29(1):61-65
Summary Cyclophosphamide demonstrates enhanced tumoricidal activity with decreased bone marrow toxicity when given on a divided-dose schedule in certain animal models. A total of 22 patients presenting with refractory metastatic cancer were treated in a phase I trial of continuous infusion of cyclophosphamide over 96 h. Granulocytopenia of <500/l that lasted for > 14 days or thrombocytopenia of <25,000/l that lasted for > 14 days was the target dose-limiting toxicity in the absence of nonhematologic grade 4 toxicity. The maximal tolerated dose was 7 g/m2. Three patients died. Of 21 evaluable patients, 9 responded, including 8/9 who had experienced disease progression during prior oxazaphosphorine-containing combination chemotherapy. Clinically meaningful responses were observed in patients who had demonstrated clinical resistance to an oxazaphosphorine drug given at lower doses.Supported in part by U.S. Public Health Service grant P01CA-38493 and by a grant from the Mather's Foundation. Two of the authors (J. P. E. and A. D. E.) are recipients of Career Development awards from the American Cancer Society, and one (T. C. S.) is a recipient of a Faculty Development Award from the Pharmaceutical Manufacturer's Association Foundation 相似文献
36.
K Suzuki T Ezoe J Tohyama J Matsuda MT Vanier K Suzuki 《Acta paediatrica (Oslo, Norway : 1992)》2003,92(S443):54-62
Spontaneously occurring genetic lysosomal storage diseases are as rare in other mammalian species as in man. However, the advent of gene targeting technology has revolutionized the state of animal models of genetic diseases. Nearly all lysosomal storage diseases known in man have been duplicated in the mouse. The technology now allows, not only complete inactivation of endogenous genes, but also the introduction of essentially any type of mutation. These animal models can overcome many of the limitations inherent in studies of human patients - rarity of the disease, extremely complex genetic background and logistical and ethical constraints in the design and execution of experiments with human subjects. For example, genetic manipulations of germ cells or cross-breeding experiments between two mutants are readily feasible with animal models. Two major areas of the utility of animal models are the clarification of the pathophysiology/pathogenetic mechanism of disease and the exploration of therapeutic approaches. Examples of experiments using animal models of lysosomal storage disease are presented, primarily from studies undertaken in our own laboratory.
Conclusion : Animal models have proved invaluable in extending our knowledge of the lysosomal storage diseases and exploring potential therapies. 相似文献
Conclusion : Animal models have proved invaluable in extending our knowledge of the lysosomal storage diseases and exploring potential therapies. 相似文献
37.
Hemoglobin and albumin adducts of benzene oxide among workers exposed to high levels of benzene 总被引:3,自引:0,他引:3
Yeowell-O'Connell K; Rothman N; Smith MT; Hayes RB; Li G; Waidyanatha S; Dosemeci M; Zhang L; Yin S; Titenko-Holland N; Rappaport SM 《Carcinogenesis》1998,19(9):1565-1571
Benzene oxide (BO) reacts with cysteinyl residues in hemoglobin (Hb) and
albumin (Alb) to form protein adducts (BO-Hb and BO-Alb), which are
presumed to be specific biomarkers of exposure to benzene. We analyzed
BO-Hb in 43 exposed workers and 42 unexposed controls, and BO-Alb in a
subsample consisting of 19 workers and 19 controls from Shanghai, China, as
part of a larger cross-sectional study of benzene biomarkers. The adducts
were analyzed by gas chromatography-mass spectrometry following reaction of
the protein with trifluoroacetic anhydride and methanesulfonic acid. When
subjects were divided into controls (n = 42) and workers exposed to < or
=31 (n = 21) and >31 p.p.m. (n = 22) benzene, median BO-Hb levels were
32.0, 46.7 and 129 pmol/g globin, respectively (correlation with exposure:
Spearman r = 0.67, P < 0.0001). To our knowledge, these results
represent the first observation in humans that BO-Hb levels are
significantly correlated with benzene exposure. Median BO-Alb levels in
these 3 groups were 103 (n = 19), 351 (n = 7) and 2010 (n = 12) pmol/g Alb,
respectively, also reflecting a significant correlation with exposure
(Spearman r = 0.90, P < 0.0001). The blood dose of BO predicted from
both Hb and Alb adducts was very similar. These results clearly affirm the
use of both Hb and Alb adducts of BO as biomarkers of exposure to high
levels of benzene. As part of our investigation of the background levels of
BO-Hb and BO-Alb found in unexposed persons, we analyzed recombinant human
Hb and Alb for BO adducts. Significant levels of both BO-Hb (19.7 pmol/g)
and BO-Alb (41.9 pmol/g) were detected, suggesting that portions of the
observed background adducts reflect an artifact of the assay, while other
portions are indicative of either unknown exposures or endogenous
production of adducts.
相似文献
38.
Increased aneusomy and long arm deletion of chromosomes 5 and 7 in the lymphocytes of Chinese workers exposed to benzene 总被引:4,自引:1,他引:4
Zhang L; Rothman N; Wang Y; Hayes RB; Li G; Dosemeci M; Yin S; Kolachana P; Titenko-Holland N; Smith MT 《Carcinogenesis》1998,19(11):1955-1961
Two of the most common cytogenetic changes in therapy- and chemical-
related leukemia are the loss and long (q) arm deletion of chromosomes 5
and 7. The detection of these aberrations in lymphocytes of individuals
exposed to potential leukemogens may serve as useful biomarkers of
increased leukemia risk. We have used a novel fluorescence in situ
hybridization (FISH) procedure to determine if specific aberrations in
chromosomes 1, 5 and 7 occur at an elevated rate in the blood cells of
workers exposed to benzene. Forty-three healthy workers exposed to a wide
range of benzene concentrations (median 31 p.p.m., 8 h time-weighted
average) and 44 unexposed controls from Shanghai were studied. Whole blood
was cultured and metaphase spreads were harvested at 72 h. Benzene exposure
was associated with increases in the rates of monosomy 5 and 7 but not
monosomy 1 (P < 0.001, P < 0.0001 and P = 0.94, respectively) and
with increases in trisomy and tetrasomy frequencies of all three
chromosomes. Long arm deletion of chromosomes 5 and 7 was increased in a
dose-dependent fashion (P = 0.014 and P < 0.0001) up to 3.5-fold in the
exposed workers. These results demonstrate that leukemia-specific changes
in chromosomes 5 and 7 can be detected by FISH in the peripheral blood of
otherwise healthy benzene-exposed workers. We suggest that aberrations in
chromosomes 5 and 7 may be useful biomarkers of early biological effect for
benzene exposure.
相似文献
39.
Neuropsychological functioning in end-stage renal disease. 总被引:2,自引:0,他引:2
H N Bawden P Acott J Carter D Lirenman G W MacDonald M McAllister M C McDonnell S Shea J Crocker 《Archives of disease in childhood》2004,89(7):644-647
AIMS: To compare the neuropsychological functioning and behaviour of children with non-syndromic end-stage renal disease (ESRD) and sibling controls. METHODS: The study was carried out at two tertiary care paediatric teaching hospitals, in Halifax and Vancouver, Canada. Children with ESRD were on a renal transplant waiting list and either pending dialysis or on dialysis therapy. Twenty two patient-sibling pairs were evaluated. Neuropsychological assessments consisting of measures of intelligence, academic achievement, memory, and motor abilities were carried out. Maternal ratings of behaviour and self-report rating of self-esteem were collected. RESULTS: The Verbal, Performance, and Full Scale IQs of patients with ESRD were significantly lower than the IQs of the sibling controls. The mean differences were 8.6, 11.7, and 10.9 points, respectively. ESRD patients also had significantly more difficulty on measures of fine motor coordination and ability to copy geometric designs than sibling controls. There were no differences between groups on measures of academic achievement, memory, behaviour, or self-esteem. CONCLUSIONS: Although children with ESRD exhibited mild deficits on measures of intelligence and some measures of motor abilities, their neuropsychological outcome was more favourable than earlier reports indicated. 相似文献
40.
Recent advances in modern perinatal and neonatal intensive care have led to an increase in the survival of premature infants. This increased survival, unfortunately, has not been accompanied by an improvement in neurodevelopmental outcomes. Premature infants, especially those with an extremely low birth weight (less than 1000 g) or those born at less than 28 weeks’ gestation, are at increased risk of major disabilities and complex, ‘low severity’ dysfunctions that have significant, lasting effects on their school function, academic performance and behaviour, as well as on family function. Neonatal follow-up programs provide a number of functions to centres providing neonatal intensive care, including quality assurance and audits, research and follow-up clinical care to neonatal intensive care unit survivors and their families. The challenge for neonatal follow-up programs is to meet the often competing objectives of providing clinical services to children and their families while providing quality assurance and audits, and high-quality long-term outcome research components, given the available resources. There is also a need for ongoing research to develop and evaluate effective postdischarge intervention programs to improve the long-term outcome of prematurity and other neonatal complications. Developmental paediatricians – with their background and training in the provision of specialized health care to children and their care-givers with respect to developmental and psychosocial well-being, and in conducting developmental and behavioural disabilities research – play a valuable role in the follow-up assessment and care of neonatal intensive care unit graduates, and strengthen the multidisciplinary research groups necessary to assess long-term outcomes and the effects of perinatal and postdischarge interventions. 相似文献