全文获取类型
收费全文 | 13348篇 |
免费 | 960篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 308篇 |
儿科学 | 351篇 |
妇产科学 | 259篇 |
基础医学 | 2036篇 |
口腔科学 | 385篇 |
临床医学 | 1320篇 |
内科学 | 3250篇 |
皮肤病学 | 162篇 |
神经病学 | 1138篇 |
特种医学 | 453篇 |
外科学 | 1653篇 |
综合类 | 86篇 |
一般理论 | 7篇 |
预防医学 | 1009篇 |
眼科学 | 217篇 |
药学 | 888篇 |
中国医学 | 19篇 |
肿瘤学 | 786篇 |
出版年
2023年 | 94篇 |
2022年 | 95篇 |
2021年 | 173篇 |
2020年 | 173篇 |
2019年 | 239篇 |
2018年 | 236篇 |
2017年 | 215篇 |
2016年 | 241篇 |
2015年 | 255篇 |
2014年 | 301篇 |
2013年 | 471篇 |
2012年 | 582篇 |
2011年 | 605篇 |
2010年 | 368篇 |
2009年 | 361篇 |
2008年 | 634篇 |
2007年 | 538篇 |
2006年 | 565篇 |
2005年 | 582篇 |
2004年 | 517篇 |
2003年 | 473篇 |
2002年 | 429篇 |
2001年 | 476篇 |
2000年 | 410篇 |
1999年 | 364篇 |
1998年 | 142篇 |
1997年 | 110篇 |
1996年 | 127篇 |
1995年 | 118篇 |
1994年 | 113篇 |
1993年 | 111篇 |
1992年 | 270篇 |
1991年 | 295篇 |
1990年 | 318篇 |
1989年 | 316篇 |
1988年 | 229篇 |
1987年 | 252篇 |
1986年 | 247篇 |
1985年 | 241篇 |
1984年 | 177篇 |
1983年 | 170篇 |
1982年 | 118篇 |
1980年 | 82篇 |
1979年 | 167篇 |
1978年 | 113篇 |
1977年 | 94篇 |
1975年 | 94篇 |
1974年 | 106篇 |
1973年 | 96篇 |
1971年 | 81篇 |
排序方式: 共有10000条查询结果,搜索用时 85 毫秒
11.
Anal sphincter size measured by endosonography in healthy volunteers. Effect of age, sex, and parity. 总被引:8,自引:0,他引:8
M B Nielsen C Hauge O O Rasmussen M S?rensen J F Pedersen J Christiansen 《Acta radiologica (Stockholm, Sweden : 1987)》1992,33(5):453-456
The anal sphincter muscles consist of the circular internal and external sphincters together with the sling-shaped associated puborectalis muscle. Ten men, 10 women with no vaginal deliveries, and 10 women with one or more vaginal deliveries were studied with anal endosonography using a 7 MHz multiplanar endoprobe. The thickness of the internal sphincter and the thickness, length, and cross-sectional area of the external sphincter were measured and related to age, sex, and parity. Reproducibility was assessed by similar measurements on different days in 10 volunteers. Anal sphincter size was the same in men and women and was not affected by the number of child births. Internal sphincter muscle thickness increased with age. Anal manometry and electromyography with an anal sponge were performed in all volunteers but the results did not correlate to any of the anal sphincter dimensions. Our conclusion is that although there are some limitations, endosonography can be used to determine the size of the anal sphincter muscles. 相似文献
12.
13.
Microalbuminuria as a predictor of preeclampsia. 总被引:1,自引:0,他引:1
K F Konstantin-Hansen H Hesseldahl S M Pedersen 《Acta obstetricia et gynecologica Scandinavica》1992,71(5):343-346
Urinary albumin concentration (UA) and albumin/creatinine ratio (UA/UC) in early morning specimens were assayed in 225 consecutive pregnant women at 20, 26, 28 and 30 weeks of gestation. 193 did not develop preeclampsia (control group), 14 developed preeclampsia later (preeclamptic group), 9 were excluded and 9 dropped out. Reference intervals of UA and UA/UC of healthy pregnant women (wk 20-30) was obtained. A statistically significant increase in urinary albumin excretion was observed with increasing gestational age as a normal phenomenon. There was no significant difference in the values of UA and UA/UC in the preeclamptic group when compared with the control group at the same stage of gestation. This indicates that microalbuminuria cannot be used as a predictor of preeclampsia. 相似文献
14.
S S Pedersen H M?ller F Espersen C H S?rensen T Jensen N H?iby 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》1992,100(4):326-334
Patients with cystic fibrosis commonly acquire chronic pulmonary infection with alginate-producing Pseudomonas aeruginosa. The infection remains localized at the mucosal surfaces of the airways. Using enzyme-linked immunosorbent assays immunoglobulin concentrations and titers of specific antibodies to purified P. aeruginosa alginate and to P. aeruginosa sonicated antigens were measured in tears, saliva, sputum and serum. CF patients had significantly higher concentrations of IgG, IgA and SIgA in serum and saliva than controls. They also had significantly higher levels of specific antibodies to alginate and sonicated antigen in secretions and serum. Local production of IgA, IgG and IgM antibodies to P. aeruginosa was demonstrated. Only a minor proportion of specific IgA antibodies were present as secretory IgA in tears, saliva and sputum. The ratio of alginate-specific SIgA to specific monomeric IgA in sputum was significantly lower than the similar ratio in saliva, whereas the same ratio for specific P. aeruginosa sonicate antigens was found in saliva and sputum. 相似文献
15.
16.
L. Lund H. Henmar P. A. Würtzen G. Lund N. Hjortskov J. N. Larsen 《Clinical and experimental allergy》2007,37(4):564-571
BACKGROUND: Specific immunotherapy with intact allergen vaccine is a well-documented treatment for allergic diseases. Different vaccine formulations are currently commercially available, the active ingredient either being intact allergens or chemically modified allergoids. The rationale behind allergoids is to decrease allergenicity while maintaining immunogenicity. However, data from the German health authorities based on reporting of adverse events over a 10-year period did not indicate increased safety of allergoids over intact allergens. OBJECTIVE: The objective of this study was to investigate the effect of chemical modification on allergenicity and immunogenicity comparing four commercial allergoid products for birch pollen immunotherapy with an intact allergen vaccine. METHODS: Solid-phase IgE inhibition and histamine release assays were selected as model systems for allergenicity, and a combination of human T cell proliferation and IgG titres following mouse immunizations were used to address the immunogenicity of the intact allergen vaccine and the four allergoids. In all assays, the products were normalized with respect to the manufacturer's recommended maintenance dose. RESULTS: IgE inhibition experiments showed a change in epitope composition comparing intact allergen vaccine with allergoid. One allergoid product induced enhanced histamine release compared to the intact allergens, while the other three allergoids showed reduced release. Standard T cell stimulation assays using lines from allergic patients showed a reduced response for all allergoids compared with the intact allergen vaccine regardless of the cell type used for antigen presentation. All allergoids showed reduced capacity to induce allergen-specific IgG responses in mice. CONCLUSION: While some allergoids were associated with reduced allergenicity, a clear reduction in immunogenicity was observed for all allergoid products compared with the intact allergen vaccine, and the commercial allergoids tested therefore do not fulfil the allergoid concept. 相似文献
17.
K. Bonatz A. Weiss R. Hehlmann H. -P. Aßmus M. Heine 《Journal of molecular medicine (Berlin, Germany)》1991,69(18):853-856
Summary A 40-year-old, HIV-infected female patient received antibiotic treatment for a urinary tract infection. After the initial success of therapy and a symptom-free period, she developed pneumonia with septic shock and adult respiratory distress syndrome (ARDS). In spite of intensive care and respirator therapy with positive end-expiratory pressure (PEEP), she died of infectious toxic shock. Autopsy findings showed relapsing, gramnegative, bacterial pneumonia (morphologically compatible with Klebsiella pneumonia) and secondary, invasive aspergillosis. The pathogenesis and epidemiology of these unusual complications of AIDS are discussed.Abbreviations AIDS
acquired immunodeficiency syndrome
- ARDS
adult respiratory distress syndrome
- CDC
Centers for Disease Control
- HIV
human immunodeficiency virus
- PEEP
positive end-expiratory pressure 相似文献
18.
Local circuit neurons of macaque monkey striate cortex: I. Neurons of laminae 4C and 5A 总被引:6,自引:0,他引:6
J S Lund 《The Journal of comparative neurology》1987,257(1):60-92
A study has been made, using Golgi preparations, of the organization of neurons with smooth or sparsely spined dendrites, here called local circuit neurons, of the macaque monkey primary visual cortex. Since these neurons include those responsible for inhibitory circuitry of the cortex, a better understanding of their anatomical organization is essential to concepts of functional organization of the region. This account describes those neurons found with cell body and major dendritic spread within the thalamic recipient zone of lamina 4C and its border zone with lamina 5A. The neurons are grouped firstly in terms of in which laminar division the soma occurred--4C beta, 4C alpha or the border zone of 5A-4C beta--and secondly, into varieties on the basis of the interlaminar projection patterns of their axons. Most, if not all, of the local circuit neurons of these divisions have interlaminar axon projections as well as an arbor local to their cell body and dendritic field. These interlaminar projections are highly specific, targeting from one to five laminar divisions depending on the variety of neuron; on this basis 17 varieties of local circuit neuron are described. While the number of varieties appears dauntingly large in terms of understanding the functional circuitry of the region, the clear-cut organization of the interlaminar links may provide clues as to the information processing that concerns each neuron. The local circuit neuron axon projections can be related to a wealth of information already available concerning the laminar organization of afferent axons and efferent cell groups, the organization of spiny neuron intrinsic relays (presumed to be excitatory), and physiological properties of different laminar divisions. It is hoped that the information derived from this study can serve as a guide for correlated physiological-anatomical studies on single cells of the region. 相似文献
19.
F J Skj?rten S H Brorson B Roald E H Str?m B Lund 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》1992,100(11):1001-1007
Fifty renal biopsies were studied by immunoelectron microscopy after embedding in a partly hydrophilic polyacrylic resin (LR White). Immunofluorescence studies were carried out on frozen sections of parallel tissue samples. Polyacrylic embedding gave good preservation of the renal ultrastructure and precise localization of immunoglobulin and C3c antibodies within glomerular electron-dense deposits. Non-specific staining of plasma proteins within vascular lumina could easily be detected. There was good correlation between immunoelectron and immunofluorescence microscopy. Immunoelectron microscopy is a very sensitive method, which can detect small amounts of antigen. More cases were, however, positive by immunofluorescence than by immunoelectron microscopy. This discrepancy may be explained by difference in sample size, and by difference in resolution of morphological details (electron microscopy versus fluorescence microscopy). 相似文献
20.
M G Conlan W D Haire R P Lieberman G Lund A Kessinger J O Armitage 《Bone marrow transplantation》1991,7(3):235-240
Long-term indwelling central venous catheters have eased the administration of drugs, blood products, and hyperalimentation to patients with cancer. However, their use is associated with thrombotic complications. We report here on the thrombotic complications prospectively observed in 46 patients with refractory lymphoma (22 Hodgkin's disease, 24 non-Hodgkin's lymphoma) who had placement of one or more catheters in preparation for autologous stem cell transplantation (ASCT). Thrombosis of 26 catheters in 19 patients was observed. Specific abnormalities of hemostasis were equally common in patients who developed thrombosis and in those who did not. Thrombotic complications were more common in patients with Hodgkin's disease (13/22) than in patients with non-Hodgkin's lymphoma (6/24, p = 0.04). Although more patients with Hodgkin's disease had received prior splenectomy and/or irradiation to the area involved by thrombosis than patients with non-Hodgkin's lymphoma, the incidence of splenectomy and irradiation was similar for patients with Hodgkin's disease who developed thrombosis and those who did not. Therefore, although the etiology remains unexplained, patients with Hodgkin's disease undergoing intensive chemotherapy and ASCT appear to have a higher incidence of catheter-related thrombosis than patients with non-Hodgkin's lymphoma undergoing similar therapy. 相似文献