全文获取类型
收费全文 | 1612篇 |
免费 | 106篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 65篇 |
妇产科学 | 32篇 |
基础医学 | 253篇 |
口腔科学 | 65篇 |
临床医学 | 173篇 |
内科学 | 258篇 |
皮肤病学 | 11篇 |
神经病学 | 203篇 |
特种医学 | 28篇 |
外国民族医学 | 7篇 |
外科学 | 237篇 |
综合类 | 9篇 |
预防医学 | 140篇 |
眼科学 | 13篇 |
药学 | 85篇 |
肿瘤学 | 134篇 |
出版年
2022年 | 14篇 |
2021年 | 21篇 |
2020年 | 9篇 |
2019年 | 22篇 |
2018年 | 33篇 |
2017年 | 21篇 |
2016年 | 19篇 |
2015年 | 25篇 |
2014年 | 38篇 |
2013年 | 48篇 |
2012年 | 93篇 |
2011年 | 106篇 |
2010年 | 49篇 |
2009年 | 54篇 |
2008年 | 76篇 |
2007年 | 105篇 |
2006年 | 75篇 |
2005年 | 101篇 |
2004年 | 82篇 |
2003年 | 93篇 |
2002年 | 77篇 |
2001年 | 20篇 |
2000年 | 37篇 |
1999年 | 42篇 |
1998年 | 21篇 |
1997年 | 22篇 |
1996年 | 24篇 |
1995年 | 21篇 |
1994年 | 18篇 |
1993年 | 15篇 |
1992年 | 17篇 |
1991年 | 18篇 |
1990年 | 20篇 |
1989年 | 22篇 |
1988年 | 24篇 |
1987年 | 12篇 |
1986年 | 16篇 |
1985年 | 13篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1980年 | 12篇 |
1979年 | 17篇 |
1978年 | 10篇 |
1976年 | 10篇 |
1975年 | 9篇 |
1974年 | 9篇 |
1973年 | 11篇 |
1972年 | 8篇 |
1971年 | 12篇 |
1970年 | 14篇 |
排序方式: 共有1719条查询结果,搜索用时 15 毫秒
11.
Nicole Fellmann Mario Bedu Gil Boudet Martine Mage Marcel Sagnol Jean-Marc Pequignot Bruno Claustrat Jocelyne Brun Liliane Peyrin Jean Coudert 《European journal of applied physiology》1992,64(3):258-265
Summary The aim of the study was to investigate the inter-relationships between pituitary-adrenal hormones and catecholamines during a prolonged competition over 6 days. Plasma adrenocorticotropic hormone (ACTH), cortisol (C), -endorphin (EP), free and sulphated adrenaline (A) and noradrenaline (NA) were measured in 11 volunteer male subjects during a national Nordic-ski race (323 km). Blood samples were obtained before the competition in the evening as control (D0), and before and after each day's racing (D1–D6). The mean daily heart rate (f
c) was calculated fromf
c values recorded every minute during the race. The results showed the following: changes in meanf
c [from 147 (SEM 3) to 156 (SEM 3) beats · min–1 according to the day] were not significant during the race. Diurnal variations in ACTH, EP and C were no longer apparent after the race: evening levels were higher than their respective D0 values during the race, except on D3 when there was a lack of response to exercise in the three hormones. Unlike ACTH and EP, pre- and postexercise C values on D1 and D2 were higher than those on the subsequent days (P<0.001). In contrast, there was a progressive accumulation of A and NA in pre-and postrace concentrations which reached a plateau in about 4 days. Positive correlations between exercise responses in ACTH, C and EP were found especially on D3 and D6 (P<0.001) but there were no significant correlations between catecholamines and the other three hormones. Thus, prolonged competition over 6 days evoked different control mechanisms for hormones of the pituitary-adrenal axis and catecholamines. A sustained catecholamine release and sympathetic activation induced a progressive NA and A accumulation during the race. In contrast, the lack of a response to exercise in ACTH, EP and C on D3 suggested a dissociated central command for pituitary axis hormones and sympathetic adrenal activation. On the following days, the response to a lack of exercise, in spite of ACTH stimulation, may have reflected an adaptation of adrenal glands to prolonged stress. 相似文献
12.
Viollet L Zarhrate M Maystadt I Estournet-Mathiaut B Barois A Desguerre I Mayer M Chabrol B LeHeup B Cusin V Billette De Villemeur T Bonneau D Saugier-Veber P Touzery-De Villepin A Delaubier A Kaplan J Jeanpierre M Feingold J Munnich A 《European journal of human genetics : EJHG》2004,12(6):483-488
Chronic distal spinal muscular atrophy (Chronic DSMA, MIM (*)607088) is a rare autosomal recessive disorder characterized by a progressive motor weakness and muscular atrophy, predominating in the distal parts of the limbs. A form of Chronic DSMA gene has been previously mapped to chromosome 11q13 in the 10.3 cM interval defined by loci D11S1889 and D11S1321. By linkage analysis in 12 European Chronic DSMA families, we showed that a disease gene maps to chromosome 11q13.3 (Z(max)=6.66 at theta=0.00 at the DSM4 locus) and suggested that this condition is genetically homogeneous. Recombination events allowed us to reduce the genetic interval to a 2.6 cM region, telomeric to the IGHMBP2 gene, excluding this gene as the disease causing gene in Chronic DSMA. Moreover, partial linkage disequilibrium was found between three rare alleles at loci D11S1369, DSM4 and D11S4184 and the mutant chromosome in European patients. Analysis of the markers at these loci strongly suggests that most Chronic DSMA chromosomes are derived from a single ancestor. Refinement of the Chronic DSMA locus will hopefully allow to test candidate genes and lead to identification of the disease-causing mutations. 相似文献
13.
Screening for cognitive impairment in older African-Caribbeans 总被引:1,自引:0,他引:1
Rait G Morley M Burns A Baldwin R Chew-Graham C St Leger AS 《Psychological medicine》2000,30(4):957-963
BACKGROUND: There are increasing numbers of older African-Caribbeans in the United Kingdom. Screening instruments are commonly used in the detection of cognitive impairment, but have not been assessed within this population. This study aimed to develop culturally modified versions of screening instruments for cognitive impairment (Mini-Mental State Examination (MMSE) and Abbreviated Mental Test (AMT)) and to determine their sensitivity and specificity in the diagnosis of dementia. METHODS: The instruments were modified using a process involving a community group of African-Caribbeans and an academic group of health professionals. They were used in a two-stage study involving community resident African-Caribbeans aged 60 years or over in inner-city Manchester, comparing the screening instruments against a computerized diagnostic interview. RESULTS: One hundred and thirty people completed the study. The results for the largest subgroup, the Jamaicans (N = 96) were analysed. Effects of gender, age and education on the MMSE and AMT scores were evaluated. The correlations between the screening instruments and diagnostic interview were highly significant (P < 0.001). At appropriate cut-offs both screening instruments demonstrated high sensitivity and acceptable specificity levels. CONCLUSIONS: A defined process with lay input has assisted in producing culturally modified versions of the MMSE and AMT that perform well compared with a diagnostic interview, if an appropriate cut-off is used. They are easy to administer and acceptable to older African-Caribbean people. The results need to be viewed within the limitations of the current study. 相似文献
14.
15.
Theodore E. Milner Caroline Cloutier Andrew B. Leger David W. Franklin 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1995,107(2):293-305
In order to determine the maximum joint stiffness that could be produced by cocontraction of wrist flexor and extensor muscles, experiments were conducted in which healthy human subjects stabilized a wrist manipulandum that was made mechanically unstable by using positive position feedback to create a load with the characteristics of a negative spring. To determine a subject's limit of stability, the negative stiffness of the manipulandum was increased by increments until the subject could no longer reliably stabilize the manipulandum in a 1° target window. Static wrist stiffness was measured by applying a 3° rampand-hold displacement of the manipulandum, which stretched the wrist flexor muscles. As the load stiffness was made more and more negative, subjects responded by increasing the level of cocontraction of flexor and extensor muscles to increase the stiffness of the wrist. The stiffness measured at a subject's limit of stability was taken as the maximum stiffness that the subject could achieve by cocontraction of wrist flexor and extensor muscles. In almost all cases, this value was as large or larger than that measured when the subject was asked to cocontract maximally to stiffen the wrist in the absence of any load. Static wrist stiffness was also measured when subjects reciprocally activated flexor or extensor muscles to hold the manipulandum in the target window against a load generated by a stretched spring. We found a strong linear correlation between wrist stiffness and flexor torque over the range of torques used in this study (20–80% maximal voluntary contraction). The maximum stiffness achieved by cocontraction of wrist flexor and extensor muscles was less than 50% of the maximum value predicted from the joint stiffness measured during matched reciprocal activation of flexor and extensor muscles. EMG recorded from either wrist flexor or extensor muscles during maximal cocontraction confirmed that this reduced stiffness was due to lower levels of activation during cocontraction of flexor and extensor muscles than during reciprocal contraction. 相似文献
16.
P N Leger C Cornelise B Dupont H Ferte F Bouchet R Marchais 《Bulletin de la Societe de pathologie exotique (1990)》1990,83(5):677-679
Before undertaking a campaign of mosquito control in a tourist area, a survey on the breeding sites and the present species has been done between March and November 1989. Fifteen species have been found, ten of them new for the department. 相似文献
17.
18.
19.
Rait G Burns A Baldwin R Morley M Chew-Graham C St Leger AS Abas M 《Family practice》1999,16(6):591-595
BACKGROUND: There are increasing numbers of older African-Caribbeans in the UK. Primary care staff often feel less confident about diagnosing depression in this group. Screening instruments may assist in making diagnoses in cross-cultural consultations. OBJECTIVE: We aimed to determine the sensitivity and specificity of screening instruments for depression in older African-Caribbean people in Manchester, UK. METHODS: We carried out a two-stage study to compare three screening instruments for depression (Geriatric Depression Scale, Brief Assessment Schedule Depression Cards, Caribbean Culture Specific Screen), with a computerized diagnostic interview for mental health disorders in older adults (Geriatric Mental State). The study was set in inner-city Manchester. The subjects were community-resident African-Caribbeans aged 60 years and over; 227 subjects were approached. Of the 160 people screened, 130 agreed to diagnostic interview. The main outcome measures were Spearman correlation coefficients; these were calculated between each screening instrument and the diagnostic interview. Receiver-operating characteristic (ROC) curve analysis was used to determine appropriate sensitivity and specificity for each instrument. RESULTS: The results for the largest subgroup, the Jamaicans (n = 96/130), demonstrated highly significant correlations between screening instruments and diagnostic interview (P < 0.001). Each instrument had a high sensitivity: Brief Assessment Schedule depression cards (cut-off > or =6; sensitivity 90.9% (95% CI 58.8-99.8), specificity 82.1% (95% CI 74.0-90.3)), Caribbean Culture Specific Screen (cut-off > or =6; sensitivity 90.9% (95% CI 58.8-99.8), specificity 74.1% (95% CI 64.8-83.4)), and Geriatric Depression Scale (cut-off > or =4; sensitivity 100% (95% CI 97.1-100), specificity 69.1% (95% CI 59.6-79.2)). CONCLUSIONS: These screening instruments demonstrate high sensitivity levels, if an appropriate cut-off point is used. The culture-specific instrument did not perform better than the traditional instruments. Health professionals should approach the consultation in a culturally sensitive manner and use the validated instrument they are most familiar with. 相似文献
20.
D A Nicoll-Griffith J P Falgueyret J M Silva P E Morin L Trimble C C Chan S Clas S Leger Z Wang J A Yergey D Riendeau 《Drug metabolism and disposition》1999,27(3):403-409
The lactol derivative of a lactone cyclooxygenase-2 inhibitor (DFU) was evaluated in vivo and in vitro for its potential suitability as a prodrug. DFU-lactol was found to be 10 to 20 times more soluble than DFU in a variety of aqueous vehicles. After administration of DFU-lactol at 20 mg kg-1 p.o. in rats, a Cmax of 7.5 microM DFU was reached in the plasma. After oral administration, the ED50s of DFU-lactol in the carrageenan-induced paw edema and lipopolysaccharide-induced pyresis assays in rats are comparable with the ED50s observed when dosing with DFU. Incubations of DFU-lactol with rat and human hepatocytes demonstrated that the oxidation of DFU-lactol can be mediated by liver enzymes and that a competing pathway is direct glucuronidation of the DFU-lactol hydroxyl group. Assays with subcellular fractions from rat liver indicated that most of the oxidation of DFU-lactol occurs in the cytosolic fraction and requires NAD(P)+. Human liver cytosol can also support the oxidation of DFU-lactol to DFU when NAD(P)+ is added to the incubations. Fractionation of human liver cytosolic proteins showed that at least three enzymes are capable of efficiently effecting the oxidation of DFU-lactol to DFU. Incubations with commercially available dehydrogenases suggest that alcohol and hydroxysteroid dehydrogenases are involved in this oxidative process. These data together suggest that lactols may represent useful prodrugs for lactone-containing drugs. 相似文献