全文获取类型
收费全文 | 4049篇 |
免费 | 255篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 30篇 |
儿科学 | 151篇 |
妇产科学 | 94篇 |
基础医学 | 649篇 |
口腔科学 | 78篇 |
临床医学 | 316篇 |
内科学 | 1092篇 |
皮肤病学 | 59篇 |
神经病学 | 448篇 |
特种医学 | 64篇 |
外科学 | 349篇 |
综合类 | 29篇 |
一般理论 | 2篇 |
预防医学 | 369篇 |
眼科学 | 53篇 |
药学 | 323篇 |
中国医学 | 37篇 |
肿瘤学 | 183篇 |
出版年
2023年 | 31篇 |
2022年 | 59篇 |
2021年 | 137篇 |
2020年 | 71篇 |
2019年 | 111篇 |
2018年 | 119篇 |
2017年 | 74篇 |
2016年 | 103篇 |
2015年 | 115篇 |
2014年 | 164篇 |
2013年 | 188篇 |
2012年 | 307篇 |
2011年 | 348篇 |
2010年 | 172篇 |
2009年 | 147篇 |
2008年 | 242篇 |
2007年 | 264篇 |
2006年 | 207篇 |
2005年 | 247篇 |
2004年 | 210篇 |
2003年 | 197篇 |
2002年 | 178篇 |
2001年 | 48篇 |
2000年 | 44篇 |
1999年 | 43篇 |
1998年 | 50篇 |
1997年 | 33篇 |
1996年 | 26篇 |
1995年 | 25篇 |
1994年 | 20篇 |
1993年 | 29篇 |
1992年 | 14篇 |
1991年 | 14篇 |
1990年 | 20篇 |
1989年 | 18篇 |
1988年 | 10篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1985年 | 21篇 |
1984年 | 12篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1979年 | 10篇 |
1978年 | 13篇 |
1976年 | 10篇 |
1975年 | 9篇 |
1970年 | 8篇 |
1969年 | 13篇 |
1967年 | 8篇 |
排序方式: 共有4326条查询结果,搜索用时 15 毫秒
1.
Graciela Spivak 《Archives of toxicology》2016,90(11):2583-2594
2.
3.
Immunoglobulin M Enzyme-Linked Immunosorbent Assay Using Recombinant Polypeptides for Diagnosis of Dengue 下载免费PDF全文
Elsa Videa Maria Josefina Coloma Flavia Barreto dos Santos Angel Balmaseda Eva Harris 《Clinical and Vaccine Immunology : CVI》2005,12(7):882-884
We demonstrate that a mixture of four recombinant dengue virus E polypeptides corresponding to the N-terminal region of the envelope protein from all serotypes substitutes for standard antigens in two immunoglobulin M enzyme-linked immunosorbent assay formats with 100% concordance, making these polypeptides a useful and accessible reagent for serological diagnosis of dengue in endemic countries. 相似文献
4.
5.
H. Bonél A. Frick H. Sittek A. Heuck M. Steinborn R. G. H. Baumeister M. Reiser 《Der Radiologe》1997,37(10):785-793
Summary
Purpose of this study was to evaluate the diagnostic value of a low field dedicated MRI system in hand and wrist imaging.
All 308 exams of the hand and wrist, that were performed on a low-field dedicated MRI system (Artoscan, Esaote Biomedica,
Italy) in our institution in 1996, and high-field MRI exams performed in addition as part of the diagnostic work-up, were
evaluated and correlated to final operative (n = 64) and histologic (n = 12) reports. 90 % of all low-field MRI scans stated a diagnosis according to clinical suspicion. In 62 % the clinical question
was answered, and in 26 % additional pathologies were identified. An MR-diagnosis completely different from the clinical suspicion
was stated in 2 %. High field exams contributed additional information in 6 of 36 patients. In 3 patients a tumor was not
shown completely in the limited field-of-view of the dedicated low-field MRI-system. Frequency-selective fat-suppression pulse
sequences and a better spatial resolution were the reasons for the additional information obtained in the other three patients.
Low-field dedicated MR-imaging is a valuable method in the extensive work-up of the hand and wrist. Osseous, ligamentous and
tendinous pathologies are well depicted. Large or infiltrative tumors should be referred to a high-field system.
相似文献
6.
Elsa Murray Ph.D. Estralita Martin Douglas Burton Leonard J. Deftos 《Journal of bone and mineral research》1989,4(6):831-838
Biochemical and molecular biological studies of osteoblastic cell function and hormonal regulation are frequently confounded by the inherent cellular heterogeneity and phenotypic instability of existing in vitro and in vivo model systems. A new technique (derived from Western blotting or antibody-based detection of protein molecules bound to nitrocellulose paper) is described for identification of individual cells which synthesize osteoblast-specific gene products (bone Gla-protein, type I collagen, and alkaline phosphatase) or produce cAMP in response to parathyroid hormone (PTH) or isoproterenol. Dispersed primary neonatal rat calvariae or osteogenic sarcoma cells were “plated” on Immobilon-P (a hydrophobic transfer membrane with very high protein-binding capacity) for 30 minutes to several hours, followed by agonist treatment, formalin fixation, hematoxylin staining, and immunostaining with a battery of antibodies specific for osteoblastic products. Individual cells and their secretory zones were visualized by light microscopy and counted. Treatment with PTH with or without isoproterenol resulted in increases in the percentages of osteoblastic cells elaborating cAMP, as well as the intensity of immunostaining, but had no effects on MCF-7 cells, a nonosteoblastic breast carcinoma control line. The percentage of cells within each primary osteoblastic cell population isolated or rat osteogenic sarcoma cell clone (G2 or C12) that elaborated bone-specific proteins or that generated cAMP in response to PTH varied with time and the individual cellular preparation, reconfirming the cellular heterogeneity of these systems. This method, in conjunction with techniques such as in vitro hybridization, should prove useful in characterizing discrete osteoblastic bone cell subpopulations and in clarifying mechanisms of hormonal regulation by local and systemic agents. 相似文献
7.
Elsa J. Brochmann Murray Samuel S. Murray Mario Grisanti Maria Eugenia L. Duarte Marshall R. Urist 《Journal of orthopaedic research》1997,15(4):585-592
The SENCAR (sensitive to carcinogenesis) mouse is a unique tool for investigating the interaction between a specific defect in intracellular signaling, dietary calcium, and metabolic bone disease. The SENCAR mouse was developed by selective breeding for enhanced sensitivity to two-stage carcinogenesis. Its major genetic defect, which renders it exquisitely sensitive to stimulation with diacylglycerol or phorbol esters, is in the regulatory domain of protein kinase C, one of the primary intracellular mediators of hormonal effects. At sexual maturity, SENCAR mice are large and have big bones, but our previous pharmacokinetic studies showed that they accumulate lesscalcium under normal conditions and lose more calcium under adverse conditions than do other, standard strains of mice. To histologically define the effect of low dietary calcium on bone metabolism, we performed histomorphometric analysis of tetracycline-labeled sections of femoral bone from male SENCAR mice maintained on calcium-sufficient and calcium-deficient diets during the critical period from 10 to 14 weeks of age. The bone volume, absolute osteoid volume, and mineral apposition rate were lower at 14 than at 10 weeks of age in SENCAR mice fed 0.02 or 0.6% calcium diets. Calcium deficiency increased the architectural disarray and the probability of observing focal discontinuities in the growth plate. Thus, characteristic features of impaired bone metabolism (low bone volume and apposition rate) develop early in SENCAR mice and are exacerbated by low dietary calcium. Detailed examinations of the histology and biochemistry of SENCAR mouse bone will provide insights into the mechanisms by which specific defects in the signal transduction of protein kinase C contribute to impaired bone metabolism. 相似文献
8.
Larry E. Davis Mario Kornfeld Herbert S. Mooney Kurt J. Fiedler Kathleen Y. Haaland William W. Orrison Elsa Cernichiari Thomas W. Clarkson 《Annals of neurology》1994,35(6):680-688
For 3 months in 1969 a family in the United States that included a pregnant mother consumed pork containing methylmercury. Children, aged 20, 13, and 8 years and a neonate, developed severe neurological signs. Twenty-two years later, the 2 oldest had cortical blindness or constricted visual fields, diminished hand proprioception, choreoathetosis, and atentional deficits. Magnetic resonance images showed tissue loss in the calcarine and parietal cortices and cerebellar folia. The youngest had quadriplegia, blindness, and severe mental retradation until their deaths. The brain of the 8-year-old who died at age 30 showed cortical atrophy, neuronal loss, and gliosis, most pronounced in the paracentral and parietooccipital regions. The total mercury level in formalin-fixed, left occipital cortex was 1,974 ng/gm as measured by atomic absorption. Regional brain mercury levels correlated with extent of brain damage. A control patient had 38.5 ng of mercury/gm in the occipital cortex. Systemic organs in the patient and a control subject had comparable mercury levels. In mercury-intoxicated rats, we found that only 5 to 10% of total brain mercury was lost by formalin fixation. Brain inorganic mercury in the patient ranged from 82 to 100%. Since inorganic mercury crosses the blood-brain barrier poorly, biotransformation of methyl to inorganic mercury may have occurred after methylmercury crossed the blood-brain barrier, accounting for its persistence in brain and causing part of the brain damage. 相似文献
9.
Terry Kwong MB BS FRACP Senior Fellow Elsa Valderrama MD Assistant Professor of Pediatric Pathology Carole Paley MD Assistant Professor of Pediatrics Norman Ilowite MD Associate Professor of Pediatrics 《Seminars in arthritis and rheumatism》1994,23(6)
Childhood sarcoidosis is a rare disorder with protean manifestations. The case of a child with prolonged fever, hepatosplenomegaly, pancytopenia, and systemic necrotizing vasculitis manifesting as fever, rash and skin infarctions, digital pregangrene, and foot drop is reported. This is the first case of systemic necrotizing vasculitis reported in sarcoidosis. The fulminant course of the disease required treatment with intravenous pulsed cyclophosphamide and high doses of corticosteroids. The spectrum of vasculitis in childhood and adult sarcoidosis is reviewed. 相似文献
10.
A A Baumeister 《Brain research》1991,557(1-2):136-145
This study examined the effects of bilateral intranigral microinjection of selective opioid agonists on the tail-flick and hot-plate antinociception tests. The principal findings are: (1) the mu-selective agonist D-Ala2, N-Me-Phe4, Gly5-ol-enkephalin (DAGO) had antinociceptive effects on both tests which were reversible by beta-funaltrexamine (beta-FNA: a mu-selective antagonist) and naloxone (a non-selective opioid antagonist); (2) the antinociceptive potency of DAGO injected into the nigra is comparable to its potency in the periaqueductal gray; (3) intranigral D-Pen2, D-Pen5-enkephalin (a delta-selective agonist), U-50, 488H and dynorphin A-(1-13) (kappa-selective agonists) had no antinociceptive effects; (4) antinociceptive effects were produced by the mixed delta/mu agonists D-Thr2-leucine enkephalin-Thr (DTLET) and D-Ser2-leucine enkephalin-Thr (DSLET); (5) the effect of DTLET on the hot-plate but not the tail-flick test was reversed by Cys2, Tyr3, Orn5, Pen7-amide (CTOP; a mu-selective antagonist), beta-FNA, and naloxone, but not by the delta-selective antagonist naltrindole. Based on the potent antinociceptive effects of DAGO, the complete lack of such effects by the highly selective delta and kappa agonists, and the antagonism of DTLET by CTOP and beta-FNA, it is concluded that the antinociceptive effects of intranigral opioid agonists are mediated by mu receptors. 相似文献