全文获取类型
收费全文 | 8271篇 |
免费 | 399篇 |
国内免费 | 125篇 |
专业分类
耳鼻咽喉 | 78篇 |
儿科学 | 162篇 |
妇产科学 | 159篇 |
基础医学 | 1497篇 |
口腔科学 | 227篇 |
临床医学 | 708篇 |
内科学 | 1170篇 |
皮肤病学 | 156篇 |
神经病学 | 773篇 |
特种医学 | 204篇 |
外科学 | 519篇 |
综合类 | 702篇 |
现状与发展 | 2篇 |
预防医学 | 451篇 |
眼科学 | 238篇 |
药学 | 1146篇 |
中国医学 | 286篇 |
肿瘤学 | 317篇 |
出版年
2023年 | 101篇 |
2022年 | 93篇 |
2021年 | 238篇 |
2020年 | 217篇 |
2019年 | 306篇 |
2018年 | 297篇 |
2017年 | 225篇 |
2016年 | 148篇 |
2015年 | 177篇 |
2014年 | 495篇 |
2013年 | 493篇 |
2012年 | 476篇 |
2011年 | 551篇 |
2010年 | 383篇 |
2009年 | 356篇 |
2008年 | 347篇 |
2007年 | 371篇 |
2006年 | 319篇 |
2005年 | 289篇 |
2004年 | 272篇 |
2003年 | 220篇 |
2002年 | 197篇 |
2001年 | 109篇 |
2000年 | 95篇 |
1999年 | 107篇 |
1998年 | 91篇 |
1997年 | 91篇 |
1996年 | 89篇 |
1995年 | 72篇 |
1994年 | 71篇 |
1993年 | 53篇 |
1992年 | 62篇 |
1991年 | 46篇 |
1990年 | 51篇 |
1989年 | 51篇 |
1988年 | 42篇 |
1987年 | 32篇 |
1986年 | 38篇 |
1985年 | 272篇 |
1984年 | 159篇 |
1983年 | 164篇 |
1982年 | 134篇 |
1981年 | 124篇 |
1980年 | 94篇 |
1979年 | 56篇 |
1978年 | 22篇 |
1977年 | 18篇 |
1976年 | 19篇 |
1975年 | 16篇 |
1974年 | 9篇 |
排序方式: 共有8795条查询结果,搜索用时 46 毫秒
51.
Albertini-Yagi CS Oliveira RC Vieira JE Negri EM de Oliveira LR Saldiva PH Lorenzi-Filho G 《Respiratory physiology & neurobiology》2005,145(1):101-110
The study objectives were to compare in vitro transportability and physical properties of respiratory mucus, obtained invasively by direct collection (DC) right after endotracheal intubation and non-invasively by sputum induction with 3% hypertonic saline solution inhalation (SI) 24 h before the anesthesia. Twenty-two patients with no pulmonary disease scheduled for elective abdominal surgical procedures were studied. The parameters analyzed and the main results are as follows. (1) Transportability by cilia (MCT), SI was higher than DC (0.94+/-0.25 and 0.62+/-0.25; P<0.001). There was a significant correlation between the two methods and DC could be estimated by: DC=0.21+(0.44 SI) (r=0.44; P<0.001). (2) Transportability by cough (CC), SI was higher than DC (68.23+/-32.1 and 33.58+/-19.04 mm; P=0.002). (3) Contact angle (CA), SI was lower than DC (10+/-3 degrees and 22+/-14 degrees ; P=0.025). (4) Rheological properties (no significant difference obtained between SI and DC). These results indicated that SI changes mucus physical properties and transportability in non-expectorators. 相似文献
52.
53.
Comparative study of pituitary and bacteria-derived human growth hormone by monoclonal antibodies 总被引:1,自引:0,他引:1
We have established hybridoma lines which secrete mouse monoclonal antibodies (Mabs) to human pituitary growth hormone, hGH. Using indirect competitive ELISA and indirect passive hemagglutination inhibition twelve different Mabs were characterized with regard to cross-reactivity with the hGH-related hormones, human chorionic somatomammotropin, hCS, and human prolactin, hPRL. The reactivity of these Mabs with pituitary hGH was compared to that with either bacterially-produced methionyl-hGH or to that of reduced and S-carboxymethylated hGH, which has an altered conformation. None of the Mabs reacted with hPRL. Four did not react with hCS whereas the others showed varying degree of cross-reactivity with hCS. All Mabs reacted more weakly with reduced and S-carboxymethylated hGH than with the native form of the hormone, which was not seen with conventional rabbit antisera to hGH. Thus in the case of hGH the Mabs are superior to conventional antisera in revealing small conformational differences. However the pituitary and bacterially-derived methionyl-hGH were indistinguishable as determined by the 12 Mabs. 相似文献
54.
Calcitonin gene-related peptide in cardiovascular tissues of the rat 总被引:15,自引:0,他引:15
P K Mulderry M A Ghatei J Rodrigo J M Allen M G Rosenfeld J M Polak S R Bloom 《Neuroscience》1985,14(3):947-954
The distribution of calcitonin gene-related peptide immunoreactivity in the cardiovascular system of the rat was investigated by radioimmunoassay and immunocytochemistry. The nature of the immunoreactivity was studied by gel permeation and high performance liquid chromatography. Immunocytochemistry demonstrated the existence of calcitonin gene-related peptide-containing nerve fibres throughout the cardiovascular system. These were present in all regions of the heart, particularly in association with the coronary arteries, within the papillary muscles and within the sinoatrial and atrioventricular nodes. Calcitonin gene-related peptide-containing fibres were found mainly in the adventitia of the arteries and veins. Calcitonin gene-related peptide concentrations were high in major arteries and veins but comparatively low in the heart, aortic arch and thoracic aorta. Chromatography showed that approximately 70% of the total immunoreactivity was identical to synthetic calcitonin gene-related peptide. Calcitonin gene-related peptide concentrations in the blood vessels of rats treated neonatally with capsaicin were not found to be significantly different from those in control animals although capsaicin caused significant reductions of calcitonin gene-related peptide levels in certain other tissues. The results of this study suggest that calcitonin gene-related peptide-containing fibres are likely to be of importance in the innervation of vascular tissues and raise the possibility that these fibres are different in character from calcitonin gene-related peptide-containing fibres found in other tissues. 相似文献
55.
Monoclonal antibodies against human granulocytes and myeloid differentiation antigens 总被引:4,自引:0,他引:4
Patrice Mannoni Anna Janowska-Wieczorek A. Robert Turner Locksley McGann Jean-Michael Turc 《Human immunology》1982,5(4):309-323
Monoclonal antibodies (MCA) were obtained by immunizing BALB/c mice with 99% pure granulocytes from normal donors or with a whole leukocyte suspension obtained from a chronic myelogenous leukemia (CML) patient, and then fusing the mouse spleen cells with a 315–43 myeloma cell clone. Four MCA were selected and studied using ELISA, immunofluorescence, cytotoxicity assays, and FACS analysis. Antibodies 80H.1. 80H.3. and 80H.5 (from normals) and 81H.1 (from CML) detected antigens expressed on neutrophils. Antibodies 80H.1 and 80H.3 (lgG) also reacted with monocytes but not with other blood cell subsets. Antibodies 80H.5 and 81H.1 (lgM) were cytotoxic and reacted strongly with most of the cells of the neutrophil maturation sequence. i.e., myeloblasts, promyelocytes, myelocytes, and mature granulocytes. Antibodies 80H.5 and 81H.1 also inhibited BFU-GM and CFU-E. Antigens recognized by 80H.3. 80H.5, and 81H.1 were expressed both on a proportion of cells from HL.60, KG.1, ML.1, and K562 myeloid cell lines, and on a proportion of blast cells isolated from patients with acute myelogenous leukemia. They were not found on lymphoid cell lines or lymphoid leukemia cells. These MCA recognize either late differentiation antigens expressed on mature neutrophils and monocytes (80H.1 and 80H.3) or early differentiation antigens (80H.5 and 81H.1) specific to the granulocytic lineage. They may be useful for a better definition of those antigens specific to hematopoietic stem cells and their relationship with normal or neoplastic hematopoiesis. 相似文献
56.
Detection of IgE-mediated respiratory sensitization in workers exposed to hexahydrophthalic anhydride 总被引:10,自引:0,他引:10
57.
A J Beitz 《Neuroscience》1982,7(11):2753-2768
The sites of origin of brain stem enkephalin and substance P projections to the rodent nucleus raphe magnus were studied utilizing the combined horseradish peroxidase retrograde transport-peroxidase-antiperoxidase immunohistochemical technique. Several brain stem areas were found to contain both enkephalin- and substance P-like immunoreactive double labeled neurons following injection of horseradish peroxidase into the raphe magnus. Nuclei providing both enkephalin and substance P inputs to the raphe magnus include the nucleus reticularis paragigantocellularis, the nucleus cuneiformis, the nucleus solitarius and the trigeminal subdivision of the lateral reticular nucleus. Enkephalin projections to the raphe magnus were also found to originate from the dorsal parabrachial nucleus, the nucleus reticularis gigantocellularis pars α and from an area which corresponds to the A5 group of Dahlström &; Fuxe. Additional neurons containing substance P-like immunoreactivity and horseradish peroxidase reaction product were identified in the superior central raphe nucleus and the nucleus pontis oralis. The midbrain periaqueductal gray contributes very few enkephalin and substance P fibers to the raphe magnus.The nucleus raphe magnus is a key structure in the intrinsic analgesia system and it has also been implicated in other diverse and non-nonciceptive functions. The present study identifies several brain stem sites which provide enkephalin and substance P input to this raphe nucleus. Several of these nuclei have been implicated in central analgesic mechanisms or in non-nociceptive autonomic functions. The present investigation raises the possibility that these brain stem regions may modulate neuronal activity in the raphe magnus via enkephalin or substance P projections and thus influence the involvement of the raphe magnus in both opiate related mechanisms of pain control and non-nociceptive functions. 相似文献
58.
Class I molecules of the major histocompatibility complex bind peptides derived from cytosolic proteins and display them on the cell surface. This function alerts cytotoxic T cells to the presence of intracellular pathogens. Class I molecule assembly requires the association of the heavy chain with β2-microglobulin, accompanied by peptide loading via specific transporters. This study localizes where these assembly steps take place, using monoclonal antibodies recognizing class I molecules in different assembly states to analyze subcellular fractions of the early secretory pathway. The distribution of peptide-loaded class I molecules was more localized than the distribution of the total pool of class I molecules in the early secretory pathway. Loaded molecules colocalized with the peptide transporter, free heavy chains, and the chaperone calnexin in high density rough endoplasmic reticulum (RER) membranes. These data suggest that subunit assembly and peptide acquisition occur at the same intracellular site. Class I molecules also localized to less dense subfractions of the early secretory pathway, which contained comparatively less peptide-loaded molecules than the high density RER fractions, at steady state. Following a 15 °C temperature block, class I molecules accumulated in these less dense membrane fractions, indicating that these fractions represent the intermediate compartment where empty class I molecules are trapped in mutant cells. In the presence of cycloheximide, a pool of class I molecules recycling to the RER was detected, suggesting empty molecules recycle to acquire peptide. 相似文献
59.
目的 检验幼师女生自尊水平与心理健康的关系。方法 使用自尊量表和SCL-90量表对196名幼师女生进行测量。结果 幼师女生的心理健康总体水平不高,幼师女生自尊水平与心理健康之间存在的显著的负相关。结论 一方面幼师女生的自尊受心理健康水平的影响,特别是抑郁、强迫和人际敏感等方面;另一方面幼师女生的自尊也会影响她们的心理健康水平。 相似文献
60.
Screening microarrays of novel monoclonal antibodies for binding to T-, B- and myeloid leukaemia cells 总被引:3,自引:0,他引:3
Belov L Huang P Chrisp JS Mulligan SP Christopherson RI 《Journal of immunological methods》2005,305(1):10-19
We have developed a microarray (DotScan) that enables rapid immunophenotyping and classification of leukaemias and lymphomas by measuring the capture of cells by immobilized dots of 82 CD antibodies [Belov, L., de la Vega, O., dos Remedios, C.G., Mulligan, S.P., 2001. Immunophenotyping of leukemia using a cluster of differentiation antibody microarray. Cancer Res. 61, 4483; Belov, L., Huang, P., Barber, N., Mulligan, S.P., Christopherson, R.I., 2003. Identification of repertoires of surface antigens on leukemias using an antibody microarray. Proteomics 3, 2147]. The DotScan technology has been used to investigate the properties of 498 new antibodies submitted to the HLDA8 Workshop. These antibodies have been applied as 10 nl dots to a film of nitrocellulose on a microscope slide to make an HLDA8 microarray. After blocking the remaining nitrocellulose surface, individual arrays were incubated with each of 7 cell types from a human leukaemia cell panel consisting of three cell lines, CCRF-CEM (a T-cell acute lymphocytic leukaemia), MEC-1 (derived from B-cell chronic lymphocytic leukaemia) and HL-60 (a promyelocytic leukaemia), and four leukaemias from patients: a T-cell prolymphocytic leukaemia, a B-cell chronic lymphocytic leukaemia, and two acute myeloid leukaemias. Leukaemia cells were captured by those immobilized antibodies for which they expressed the corresponding surface molecule. Unbound cells were gently washed off, bound cells were fixed to the arrays and dot patterns were recorded using a DotScan array reader and quantified using DotScan data analysis software. The data obtained show the unique expression profiles of the 7 cell types in the leukaemia cell panel obtained with the DotScan microarray, and the differential capture patterns for these 7 cell types screened against the 498 antibodies in the HLDA8 microarray constructed for this study. 相似文献