全文获取类型
收费全文 | 17383篇 |
免费 | 808篇 |
国内免费 | 94篇 |
专业分类
耳鼻咽喉 | 177篇 |
儿科学 | 372篇 |
妇产科学 | 358篇 |
基础医学 | 1979篇 |
口腔科学 | 1453篇 |
临床医学 | 1160篇 |
内科学 | 4550篇 |
皮肤病学 | 433篇 |
神经病学 | 1411篇 |
特种医学 | 299篇 |
外科学 | 2514篇 |
综合类 | 90篇 |
一般理论 | 4篇 |
预防医学 | 1239篇 |
眼科学 | 372篇 |
药学 | 757篇 |
中国医学 | 81篇 |
肿瘤学 | 1036篇 |
出版年
2024年 | 11篇 |
2023年 | 132篇 |
2022年 | 275篇 |
2021年 | 584篇 |
2020年 | 332篇 |
2019年 | 530篇 |
2018年 | 616篇 |
2017年 | 408篇 |
2016年 | 423篇 |
2015年 | 523篇 |
2014年 | 739篇 |
2013年 | 898篇 |
2012年 | 1459篇 |
2011年 | 1584篇 |
2010年 | 896篇 |
2009年 | 733篇 |
2008年 | 1202篇 |
2007年 | 1368篇 |
2006年 | 1155篇 |
2005年 | 1015篇 |
2004年 | 895篇 |
2003年 | 742篇 |
2002年 | 757篇 |
2001年 | 88篇 |
2000年 | 60篇 |
1999年 | 72篇 |
1998年 | 113篇 |
1997年 | 96篇 |
1996年 | 82篇 |
1995年 | 53篇 |
1994年 | 55篇 |
1993年 | 44篇 |
1992年 | 25篇 |
1991年 | 22篇 |
1990年 | 23篇 |
1989年 | 11篇 |
1988年 | 16篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 12篇 |
1984年 | 26篇 |
1983年 | 19篇 |
1982年 | 11篇 |
1981年 | 24篇 |
1980年 | 20篇 |
1979年 | 10篇 |
1978年 | 8篇 |
1977年 | 18篇 |
1976年 | 13篇 |
1974年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Eduardo M. Salinas Jorge Cebada Alberto Valdés Anoland Garateix Abel Aneiros Julio L. Alvarez 《Toxicon》1997,35(12):1699-1709
The effects were studied of a toxin (Bainh) isolated from the secretion of the Caribbean sea anemone Bunodosoma granulifera on electrical and mechanical activities of rat ventricular muscle. The effects on the ionic currents of single rat and dog ventricular cardiomyocytes were studied using the whole-cell recording patch-clamp technique. In the concentration range from 1 to 10 mg/ml, Bainh increased the force of contraction and induced an increase in action potential duration of ventricular multicellular preparations. In single cardiomyocytes, at concentrations up to 10 mg/ml Bainh showed no significant effects on the sodium current. However, at 0.5–1 mg/ml it increased the L-type Ca current (ICaL) by 25–50%. This increase in ICaL was not voltage dependent and was reversible after washout. The transient outward current was not significantly affected by Bainh (1–10 mg/ml). In this concentration range, Bainh markedly (≈75%) increased the inward-going rectifier current, IK1. This effect that was not voltage dependent and was fully reversible upon returning to control solution. It is suggested that these effects on ionic currents could explain the positive inotropic action of Bainh on cardiac multicellular preparations. 相似文献
32.
Patricio López-Jaramillo Director Marcelo Narváez Professor rés Calle Professor José Rivera Consultant Patricio Jácome Registrar César Ruano Professor Eduardo Nava Consultant 《BJOG : an international journal of obstetrics and gynaecology》1996,103(1):33-38
Objective To elucidate the role of the L-arginine: nitric oxide pathway in pregnancy and pre-eclampsia.
Participants Pregnant women (nulliparous, age < 25 years). Normotensive pregnancy ( n = 22 ) was defined when blood pressure remained at levels of < 120/80 mmHg and there was no proteinuria. Women with pre-eclampsia ( n = 22 ) had blood pressure measurements of > 140/90 mmHg and proteinuria of > 300 mg/l. Nonpregnant normotensive women ( n = 22 ) were studied as controls.
Study Design Blood samples were taken for measurements of ionised calcium, atrial natriuretic factor, cyclic guanosine 3'5'monophophate (GMP), arginine and asymmetric dimethylarginine. Urine samples were collected for determination of cyclic GMP excretion. Cyclic GMP concentrations were also determined in 12 women with severe pre-eclampsia before and after treatment with hydralazine.
Results L-arginine, asymmetric dimethylarginine and atrial natriuretic factor were not different in any group. Cyclic GMP concentrations in plasma [0.94 (SD 0.23) nM] as well as in urine [50.1 (SD15.7)μM] were increased significantly ( P < 0.05 ) in normal pregnancy compared to nonpregnant controls [plasma mean 0.46 (SD 0.12) nM and urine mean 18.4 (SD 10.3) μM], but not in the pre-eclampsia group [plasma mean 0.48 (SD 0.10) nM and urine mean 24.1 (SD 14.5) μM]. Concentrations of cyclic GMP in plasma and urine increased significantly ( P < 0.05 ) in women treated with hydralazine.
Conclusions The differences in cyclic GMP concentrations may reflect differences in nitric oxide production. Hydralazine increases cyclic GMP concentrations in severely pre-eclamptic women. This action could explain the antihypertensive effect of hydralazine. 相似文献
Participants Pregnant women (nulliparous, age < 25 years). Normotensive pregnancy ( n = 22 ) was defined when blood pressure remained at levels of < 120/80 mmHg and there was no proteinuria. Women with pre-eclampsia ( n = 22 ) had blood pressure measurements of > 140/90 mmHg and proteinuria of > 300 mg/l. Nonpregnant normotensive women ( n = 22 ) were studied as controls.
Study Design Blood samples were taken for measurements of ionised calcium, atrial natriuretic factor, cyclic guanosine 3'5'monophophate (GMP), arginine and asymmetric dimethylarginine. Urine samples were collected for determination of cyclic GMP excretion. Cyclic GMP concentrations were also determined in 12 women with severe pre-eclampsia before and after treatment with hydralazine.
Results L-arginine, asymmetric dimethylarginine and atrial natriuretic factor were not different in any group. Cyclic GMP concentrations in plasma [0.94 (SD 0.23) nM] as well as in urine [50.1 (SD15.7)μM] were increased significantly ( P < 0.05 ) in normal pregnancy compared to nonpregnant controls [plasma mean 0.46 (SD 0.12) nM and urine mean 18.4 (SD 10.3) μM], but not in the pre-eclampsia group [plasma mean 0.48 (SD 0.10) nM and urine mean 24.1 (SD 14.5) μM]. Concentrations of cyclic GMP in plasma and urine increased significantly ( P < 0.05 ) in women treated with hydralazine.
Conclusions The differences in cyclic GMP concentrations may reflect differences in nitric oxide production. Hydralazine increases cyclic GMP concentrations in severely pre-eclamptic women. This action could explain the antihypertensive effect of hydralazine. 相似文献
33.
Eneida F. Vencio Rita C. Alencar Eduardo Zancope 《Journal of oral pathology & medicine》2007,36(2):120-122
A 13-year-old boy had complained of an asymptomatic swelling in the anterior maxilla for approximately 4 years. The patient reported no local trauma. The intra-oral examination revealed an exophytic lesion in the incisive papilla between the maxillary central and lateral incisor teeth. The radiographies detected no significant findings. Histopathologically, the lesion showed a dense fibrous tissue above the overlying mucosa. Bone ossification lay beneath a partially hypertrophic cartilage showing occasionally pleomorphic chondrocytes. Because of its microscopic aspects, heterotopic ossification may be mistaken for chondrosarcoma or other conditions involving periosteum, such as parosteal osteosarcoma. A case of heterotopic ossification in the anterior maxilla is presented, and clinicopathologic similarities with other osteochondromatous lesions are discussed. 相似文献
34.
35.
Eduardo M. B. Tinoco Ståle P. Lyngstadaas Hans R. Preus Per Gjermo 《Journal of clinical periodontology》1997,24(12):937-944
Abstract Immunological data have been suggested to be a potential tool in the diagnosis, classification and monitoring of periodontal diseases. However, the role of circulating antibodies in periodontal patients is poorly understood. Patients suffering from localized juvenile periodontitis (LJP) are often reported to show high titers of serum IgG antibodies against Aetinobaeillus actinomycetemcomitans (A. actinomycetemcotnitans), but several affected patients do not. Most studies use well-known reference strains of the bacterium for testing against the patients' sera. The aim of the present investigation was to study the relationship between serum IgG antibody levels to autologous A. actinomycetemcomitans strains and clinical attachment loss (CAL). In addition, we wanted to assess the patients’serum titers against 4 well-known reference strains of the bacterium as well as their general potential immunoglobulin response. Intravenous blood samples were taken from 23 LJP patients and 10 healthy individuals, and autologous A. actinomycetemcomitans strains were cultured from 18 of the L.JP patients. CAL was measured at 4 different sites around ail present teeth and assessed as a % of teeth with at least 1 site moderately ≥2<5 mm) or severely (≥5 mm) involved. An enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the serum titers of IgG antibodies to A. actinomycetemcomitans antigens. No significant correlation was found between serum IgG antibody titers to autologous strains and CAL. However, there was a trend that low responders had more moderately affected teeth than had high responders and patients with undetectable A. actinomycetemcomitans levels, which is in agreement with a hypothetically protective role of the antibodies. The total counts of immunoglobulin assessed in all participants showed that the predominant class was IgG and the reference group displayed significantly less (p<0.05) IgG and IgG1 counts than the LJP patients. Both the reaction pattern against reference and autologous strains varied widely. We conclude that the specific antibody response against A. actinomycetemcomitans shows a weak correlation to clinical attachment levels in LJP patients. 相似文献
36.
Christoph Scherfler MD Johannes Schwarz MD PhD Angelo Antonini MD PhD Donald Grosset MD Francesc Valldeoriola MD PhD Kenneth Marek MD Wolfgang Oertel MD Eduardo Tolosa MD PhD Andrew J. Lees MD Werner Poewe MD 《Movement disorders》2007,22(9):1229-1238
The diagnosis of idiopathic Parkinson's disease (PD) can be achieved with high degrees of accuracy in cases with full expression of classical clinical features. However, diagnostic uncertainty remains in early disease with subtle or ambiguous signs. Functional imaging has been suggested to increase the diagnostic yield in parkinsonian syndromes with uncertain clinical classification. Loss of striatal dopamine nerve terminal function, a hallmark of neurodegenerative Parkinsonism, is strongly related to decreases of dopamine transporter (DAT) density, which can be measured by single photon emission computed tomography (SPECT). The use of DAT‐SPECT facilitates the differential diagnosis in patients with isolated tremor symptoms not fulfilling PD or essential tremor criteria, drug‐induced, psychogenic and vascular Parkinsonism as well as dementia when associated with Parkinsonism. This review addresses the value of DAT‐SPECT in early differential diagnosis, and its potential as a screening tool for subjects at risk of developing PD as well as issues around the assessment of disease progression. © 2007 Movement Disorder Society 相似文献
37.
Background. Port-wine stains (PWSs) are capillary malformations that usually show progressive stasis of the vascular channels and cause slow hyperplasia of the soft and hard tissues. When these lesions involve the lower lip, macrocheilia may be developed along the time. Vascular-specific lasers are not adequate to correct these three-dimensional tissue deformities, and surgical management becomes necessary, resulting in considerable morbidity and aesthetic disturbances.
Objective. To report a case of macrocheilia secondary to PWS treated by combination of surgery and carbon dioxide laser.
Methods. A 51-year-old man with macrocheilia of the lower lip and severe functional impairment, secondary to long evolution PWS, received treatment with carbon dioxide laser vaporization and minimal surgical correction, resulting in significant improvement of the lower lip hypertrophy, good aesthetic and functional status, and preservation of the muscular function.
Conclusions. Combined carbon dioxide laser and surgery treatment may constitute a valuable alternative in treatment of macrocheilia secondary to PWS because bleeding risk is minimized and improves the preservation of muscular function and aesthetic results in relationship to conventional surgical approaches. 相似文献
Objective. To report a case of macrocheilia secondary to PWS treated by combination of surgery and carbon dioxide laser.
Methods. A 51-year-old man with macrocheilia of the lower lip and severe functional impairment, secondary to long evolution PWS, received treatment with carbon dioxide laser vaporization and minimal surgical correction, resulting in significant improvement of the lower lip hypertrophy, good aesthetic and functional status, and preservation of the muscular function.
Conclusions. Combined carbon dioxide laser and surgery treatment may constitute a valuable alternative in treatment of macrocheilia secondary to PWS because bleeding risk is minimized and improves the preservation of muscular function and aesthetic results in relationship to conventional surgical approaches. 相似文献
38.
39.
Wilson disease: novel mutations in the ATP7B gene and clinical correlation in Brazilian patients 总被引:1,自引:0,他引:1
Deguti MM Genschel J Cancado EL Barbosa ER Bochow B Mucenic M Porta G Lochs H Carrilho FJ Schmidt HH 《Human mutation》2004,23(4):398
Wilson disease (WD) is a rare inherited autosomal recessive disorder caused by a defect in a metal transporting P-type ATPase, resulting in copper overload in various tissues and cells. The aim was to assess both the phenotype in Brazilian WD patients and the corresponding ATP7B genotype. Sixty subjects belonging to 46 pedigrees diagnosed as WD were included in this study. Direct sequencing of all 21 exons within ATP7B and their flanking introns was performed. Demographic, clinical, laboratory and histopathological data at the time of diagnosis were obtained. We identified twenty-five mutations, twelve of them reported for the first time. The c.3402delC mutation had the highest allelic frequency (30.8%), followed by the c.2123T>C (p.L708P) (16.7%). Exons 8 and 15 were the site of 62.5% of the mutations. The common European mutation c.3207C>A (p.H1069Q) was not present at all. Phenotype varied greatly among individuals with the same ATP7B genotype. Our data confirm the heterogeneity of ATP7B genotype in Brazilian WD patients. The mutational spectrum is compatible with the Brazilian history of Mediterranean immigration; however, new mutations, and different frequencies and phenotype associated with the previously known mutations characterize this population. Exons 8 and 15 should be preferentially screened in WD cases from Brazil. Phenotype variation among subjects with the same ATP7B genotype suggests that modifying factors play an additional role in the pathogenesis of WD. 相似文献
40.
Durand-Joly I Aliouat el M Recourt C Guyot K François N Wauquier M Camus D Dei-Cas E 《Journal of clinical microbiology》2002,40(5):1862-1865
The infectious power of Pneumocystis carinii f. sp. hominis was explored by inoculating SCID mice intranasally with either P. carinii f. sp. hominis or P. carinii f. sp. muris isolates. Only mice inoculated with mouse parasites developed Pneumocystis pneumonia, as assessed by microscopy and PCR. These results suggest that humans do not contract pneumocystosis from animals. 相似文献