全文获取类型
收费全文 | 13574篇 |
免费 | 956篇 |
国内免费 | 72篇 |
专业分类
耳鼻咽喉 | 102篇 |
儿科学 | 435篇 |
妇产科学 | 488篇 |
基础医学 | 1528篇 |
口腔科学 | 322篇 |
临床医学 | 1512篇 |
内科学 | 3111篇 |
皮肤病学 | 336篇 |
神经病学 | 903篇 |
特种医学 | 549篇 |
外国民族医学 | 3篇 |
外科学 | 1815篇 |
综合类 | 480篇 |
一般理论 | 7篇 |
预防医学 | 1109篇 |
眼科学 | 431篇 |
药学 | 795篇 |
3篇 | |
中国医学 | 105篇 |
肿瘤学 | 568篇 |
出版年
2021年 | 160篇 |
2020年 | 108篇 |
2019年 | 145篇 |
2018年 | 188篇 |
2017年 | 177篇 |
2016年 | 149篇 |
2015年 | 190篇 |
2014年 | 268篇 |
2013年 | 394篇 |
2012年 | 562篇 |
2011年 | 582篇 |
2010年 | 394篇 |
2009年 | 356篇 |
2008年 | 567篇 |
2007年 | 542篇 |
2006年 | 567篇 |
2005年 | 569篇 |
2004年 | 491篇 |
2003年 | 447篇 |
2002年 | 452篇 |
2001年 | 473篇 |
2000年 | 418篇 |
1999年 | 346篇 |
1998年 | 137篇 |
1997年 | 138篇 |
1996年 | 141篇 |
1995年 | 124篇 |
1994年 | 129篇 |
1993年 | 126篇 |
1992年 | 343篇 |
1991年 | 333篇 |
1990年 | 301篇 |
1989年 | 311篇 |
1988年 | 283篇 |
1987年 | 296篇 |
1986年 | 247篇 |
1985年 | 239篇 |
1984年 | 189篇 |
1983年 | 167篇 |
1982年 | 100篇 |
1981年 | 106篇 |
1980年 | 114篇 |
1979年 | 174篇 |
1978年 | 138篇 |
1977年 | 126篇 |
1976年 | 97篇 |
1975年 | 101篇 |
1974年 | 116篇 |
1973年 | 116篇 |
1972年 | 97篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
91.
A comparison of cocaine, lidocaine with epinephrine, and oxymetazoline for prevention of epistaxis on nasotracheal intubation 总被引:1,自引:0,他引:1
R I Katz A R Hovagim H S Finkelstein Y Grinberg R V Boccio P J Poppers 《Journal of clinical anesthesia》1990,2(1):16-20
The alpha-adrenergic agonist oxymetazoline was compared to cocaine and to lidocaine with epinephrine with respect to prevention of epistaxis on nasotracheal intubation. The nares of three groups of 14 patients each were topically pretreated with 4% lidocaine with 1:100,000 epinephrine (group 1), 10% cocaine (group 2), or 0.05% oxymetazoline (group 3) prior to nasotracheal intubation. After intubation, epistaxis was estimated on a scale of 0 to 3, with 0 indicating no bleeding, 1 representing blood on the nasotracheal tube only, 2 indicating blood pooling in the pharynx, and 3 representing blood in the pharynx sufficient to impede intubation. Only 29% of the patients in group 1 displayed no bleeding, whereas 57% of those in group 2 and 86% of those in group 3 had no bleeding. Nonparametric analysis showed a statistically significant difference (p less than 0.013) between oxymetazoline and lidocaine with epinephrine. In addition, heart rate (HR) and blood pressure (BP) were examined prior to administration of the medications; at 5 minutes, 10 minutes, and 15 minutes after administration of the medications; and after intubation. No significant differences were noted (p greater than 0.05) between the medications except for a slightly higher systolic BP for cocaine than for lidocaine with epinephrine at 15 minutes. The results of this double-blind, randomized trial demonstrate that the alpha-adrenergic agonist oxymetazoline is as effective as cocaine, and more effective than lidocaine with epinephrine, for the prevention of epistaxis associated with nasotracheal intubation. 相似文献
92.
Thirty-five posters were presented at the Workshop on Brain Uptake And Utilization Of Fatty Acids, Lipids, and Lipoproteins.
They were grouped into four categories: (1) mechanisms of lipid uptake and transport to the brain, (2) lipoproteins and polyunsaturated
fatty acids, (3) eicosanoids in brain function, and (4) fatty acids and lipids in brain disorders. This article summarizes
the highlights of the research presented in these posters. The individual abstracts follow these synopses. 相似文献
93.
Pheochromocytoma and paraganglioma: comparison of MR imaging with CT and I-131 MIBG scintigraphy 总被引:6,自引:0,他引:6
To ascertain the magnetic resonance (MR) imaging characteristics of pheochromocytomas and paragangliomas and to compare MR with computed tomography (CT) and iodine-131 metaiodobenzylguanidine (I-131 MIBG), 19 patients (18 with pheochromocytomas, one with a paraganglioma) were studied. The 18 patients with pheochromocytomas had had positive findings with I-131 MIBG scintigraphy. Abdominal pheochromocytomas were generally hypointense compared with normal liver on T1-weighted MR images and extremely hyperintense on T2-weighted MR images. MR imaging was preferable to CT in the evaluation of primary pheochromocytomas due to superior tissue characterization, particularly in the patient with hypertension and borderline catecholamine levels. For patients with recurrent or metastatic disease, the data suggest that I-131 MIBG scintigraphy is the examination of choice. 相似文献
94.
95.
Isolated granulomatous disease was identified in a gastrectomy specimen after a gastrointestinal hemorrhage in a 61-year-old white woman. She died postoperatively. No other areas of granulomatous tissue were identified at autopsy. Ten years previously, pulmonary sarcoidosis was proven on lung biopsy. Conceivable, other reported cases of unexplained "idiopathic" granulomatous disease of the stomach may represent residua of prior disseminated sarcoidosis. 相似文献
96.
Sir Martin Roth has stated, "where there is depression, there is hope," to emphasize the fact that depression can be a treatable source of excess disability, even when it is superimposed upon irreversible chronic medical illness. Both the potential benefits and the risks of antidepressant medications are increased in the frail elderly. This article presents an approach toward defining who should be treated and for ensuring that elderly patients receive adequate treatment. 相似文献
97.
Bone marrow transplantation in miniature swine. III. Graft-versus-host disease and the effect of T cell depletion of marrow 总被引:1,自引:0,他引:1
K Sakamoto D H Sachs S Shimada F A Popitz-Bergez L R Pennington M D Pescovitz M A McDonough T J MacVittie S I Katz R E Gress 《Transplantation》1988,45(5):869-875
Graft-versus-host disease (GVHD) has been evaluated in partially inbred miniature swine in order to study this complication of allogeneic bone marrow transplantation (BMT) in a major histocompatibility complex (MHC) genetically defined large animal model. Bone marrow from MHC homozygous ("parental") swine was injected into irradiated (900 rads total-body irradiation) MHC heterozygous ("F1") swine that shared one haplotype with the donor. All 18 animals successfully engrafted with donor bone marrow, and 17 of these developed skin rash of varying intensity depending on the extent of T cell depletion of infused marrow. Of 18 animals, 8 received undepleted bone marrow from exsanguinated donors and 2 also received additional peripheral blood lymphocytes (PBL) as a source of mature T cells. All 8 showed a moderate-to-severe rash, and the 2 pigs that received additional donor PBL developed the most severe rash. The cutaneous eruption seen in this model clinically, histologically, and immunologically resembled human GVHD. Two protocols of T cell depletion of donor bone marrow by antiporcine T cell monoclonal antibodies plus complement were tested for their effect on development of GVHD. The combination of two monoclonal antibodies, 74-12-4 (PT4) and 76-2-11 (PT8), had a marginal effect on the subsequent development of cutaneous manifestations of GVHD. However, treatment of the donor marrow by a combination of three monoclonal antibodies--PT4, PT8, and MSA4 (PT11)--effectively decreased the severity of the GVHD skin rash. These results indicate that (1) the GVHD associated with allogeneic bone marrow transplantation in swine is dependent on T cells in the marrow; (2) effective T cell depletion of donor marrow by monoclonal antibodies and complement does not prevent engraftment; and (3) this swine GVHD model, which allows study with F1 and homozygous parental combinations in an MHC genetically defined large animal, is particularly useful for the understanding of GVHD pathogenesis, prevention, and treatment. 相似文献
98.
Experiments were designed to evaluate the effect of recombinant IL-2 on growth of hemopoietic precursors from different sources (normal cord blood and bone marrow, and PB from CGL patients). For this purpose, combined cell sorting techniques and multipotent colony forming cell assays were used. A monoclonal antibody BI-3C5, which recognizes an antigen present on early lympho-myeloid cells as well as on all colony forming cells (CFU-GEMM assay), was used to enrich the studied populations. Double colour immunofluorescence techniques were performed to analyse the expression of Tac antigen on early progenitors. The results showed that rIL-2 had a stimulatory effect on growth of enriched progenitors from the three sources and surprisingly that addition of anti-Tac did not abolish this effect. On the contrary, anti-Tac enhanced even more growth of these sorted BI-3C5 precursors, suggesting a ligand action of the antibody. More interestingly, a low percentage of cord cells (1 in 1000) expressed both BI-3C5 and Tac antigens. The vast majority of cells did not concomitantly express both markers. The double labelled cells had a lymphoid-like morphology, high nucleus/cytoplasmic ratio and 2-3 nucleoli. The results will be discussed focusing on early and late "stem" cell growth. 相似文献
99.
The myocardium in congestive heart failure 总被引:1,自引:0,他引:1
A M Katz 《The American journal of cardiology》1989,63(2):12A-16A
It is now apparent that the myocardium in patients with congestive heart failure (CHF) is not normal, because important structural and molecular changes modify function in these hearts. It appears likely that the myocardium in these patients with CHF becomes unable to provide enough chemical energy to meet its mechanical requirements. If this interpretation is correct, the resulting condition of "energy starvation" would have several important implications for therapy. For example, inotropic stimulation, by increasing energy expenditure, could contribute to the progressive myocardial cell death that characterizes end-stage cardiac hypertrophy. Conversely, the reduction in myocardial contractility that develops in the chronically over-loaded heart reduces myocardial energy expenditure, and changes in the expression of myosin isoforms improve cardiac efficiency. Therefore, an important goal of therapy in the patient with CHF is to reduce energy expenditure by unloading the failing heart and, in some cases, by administration of negative inotropic drugs. 相似文献
100.
The relationships between ocular dominance columns and intrinsic cortical circuitry were examined in brain slices prepared from the striate cortex of macaques. Ocular dominance columns in layer 4C beta were visualized in vitro following anterograde transport of rhodamine injected into the lateral geniculate nucleus in vivo. The axonal and dendritic arborizations of individual layer 4C beta cells were revealed by intracellular fluorescent dye injections. Both qualitative observations and quantitative analysis showed that the dendrites of cells close to borders remained preferentially, although not absolutely, in the "home" column (the column containing the cell body). Thus, the segregated pattern of afferent input appears to have considerable influence on the pattern of dendritic arbors. Similarly, while axon collaterals within layer 4C beta could cross into the adjacent column, their limited lateral spread produced arbors that remained primarily within the home column. The terminal arbors of collaterals that travelled from layer 4C beta to layer 3 had a larger lateral spread, and the termination pattern appeared to be independent of column borders. Thus, our observations indicate that, while the course of many layer 4C beta dendrites appears to be guided by columnar boundaries as defined by geniculate afferents, there exist morphological substrates for intercolumnar interactions even between 4C beta cells. Intercolumnar interactions are seen more commonly in layer 3, however, where larger, denser axon arbors originating from 4C beta cells can freely cross ocular dominance column boundaries. 相似文献