全文获取类型
收费全文 | 9733篇 |
免费 | 801篇 |
国内免费 | 86篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 458篇 |
妇产科学 | 187篇 |
基础医学 | 1469篇 |
口腔科学 | 356篇 |
临床医学 | 1091篇 |
内科学 | 1780篇 |
皮肤病学 | 172篇 |
神经病学 | 1062篇 |
特种医学 | 452篇 |
外科学 | 1032篇 |
综合类 | 224篇 |
一般理论 | 10篇 |
预防医学 | 799篇 |
眼科学 | 124篇 |
药学 | 744篇 |
中国医学 | 30篇 |
肿瘤学 | 605篇 |
出版年
2021年 | 137篇 |
2020年 | 98篇 |
2019年 | 143篇 |
2018年 | 151篇 |
2017年 | 122篇 |
2016年 | 134篇 |
2015年 | 143篇 |
2014年 | 195篇 |
2013年 | 308篇 |
2012年 | 441篇 |
2011年 | 405篇 |
2010年 | 291篇 |
2009年 | 239篇 |
2008年 | 424篇 |
2007年 | 426篇 |
2006年 | 393篇 |
2005年 | 383篇 |
2004年 | 345篇 |
2003年 | 355篇 |
2002年 | 330篇 |
2001年 | 296篇 |
2000年 | 290篇 |
1999年 | 247篇 |
1998年 | 161篇 |
1997年 | 155篇 |
1996年 | 138篇 |
1995年 | 145篇 |
1994年 | 108篇 |
1993年 | 115篇 |
1992年 | 188篇 |
1991年 | 228篇 |
1990年 | 170篇 |
1989年 | 234篇 |
1988年 | 232篇 |
1987年 | 285篇 |
1986年 | 208篇 |
1985年 | 254篇 |
1984年 | 151篇 |
1983年 | 117篇 |
1982年 | 94篇 |
1981年 | 95篇 |
1980年 | 85篇 |
1979年 | 106篇 |
1978年 | 112篇 |
1977年 | 98篇 |
1976年 | 68篇 |
1975年 | 79篇 |
1974年 | 77篇 |
1973年 | 72篇 |
1972年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Sclerochoroidal calcification is an uncommon condition. Metabolic evaluation and clinical examination are important to exclude associated systemic conditions such as the Bartter and Gitelman syndromes. It has been suggested that the lesions seen in sclerochoroidal calcification are calcium pyrophosphate dihydrate crystals. This report describes the first documented case in the UK of sclerochoroidal calcification associated with Gitelman syndrome and calcium pyrophosphate dihydrate deposition. 相似文献
62.
Porphyromonas gingivalis RgpA and Kgp proteinases and adhesins are C terminally processed by the carboxypeptidase CPG70 下载免费PDF全文
Porphyromonas gingivalis is a bacterial pathogen that produces the polyproteins RgpA and Kgp, which are proteolytically processed into proteinases and adhesins. We have demonstrated that the RgpA and Kgp proteinases and adhesins are C terminally processed by carboxypeptidase CPG70 by sequencing C-terminal peptides from both the wild type and an isogenic CPG70 mutant, using ion trap mass spectrometry. 相似文献
63.
Evans CM Williams OW Tuvim MJ Nigam R Mixides GP Blackburn MR DeMayo FJ Burns AR Smith C Reynolds SD Stripp BR Dickey BF 《American journal of respiratory cell and molecular biology》2004,31(4):382-394
Airway mucus hypersecretion is a prominent feature of many obstructive lung diseases. We thus determined the ontogeny and exocytic phenotype of mouse airway mucous cells. In naive mice, ciliated (approximately 40%) and nonciliated (approximately 60%) epithelial cells line the airways, and > 95% of the nonciliated cells are Clara cells that contain Clara cell secretory protein (CCSP). Mucous cells comprise < 5% of the nonciliated cells. After sensitization and a single aerosol antigen challenge, alcian blue-periodic acid Schiff's positive mucous cell numbers increase dramatically, appearing 6 h after challenge (21% of nonciliated/nonbasal cells), peaking from Days 1-7 (99%), and persisting at Day 28 (65%). Throughout the induction and resolution of mucous metaplasia, ciliated and Clara cell numbers identified immunohistochemically change only slightly. Intracellular mucin content peaks at Day 7, and mucin expression is limited specifically to a Clara cell subset in airway generations 2-4 that continue to express CCSP. Functionally, Clara cells are secretory cells that express the regulated exocytic marker Rab3D and, in antigen-challenged mice, rapidly secrete mucin in response to inhaled ATP in a dose-dependent manner. Thus, Clara cells show great plasticity in structure and secretory products, yet have molecular and functional continuity in their identity as specialized apical secretory cells. 相似文献
64.
Mariner DJ Sirotkin H Daniel JM Lindman BR Mernaugh RL Patten AK Thoreson MA Reynolds AB 《Hybridoma》1999,18(4):343-349
We have generated the first monoclonal antibodies (MAbs) to Armadillo repeat gene deleted in velo-cardiofacial syndrome (ARVCF), a recently identified Armadillo repeat-containing protein closely related to the catenin p120ctn. Six ARVCF-specific MAbs were characterized for isotype, species cross-reactivity, and utility in assays including immunofluorescence, immunoprecipitation, and Western blotting. All six antibodies were isotyped as IgG1 and several cross-reacted with ARVCF from a variety of species including human, rat, dog, and monkey, but not mouse. Importantly, none of the ARVCF MAbs cross-reacted with p120ctn, despite the high homology between these proteins. MAbs 3B2 and 4B1 were consistently the best in all applications and will provide valuable tools for further study of the role of ARVCF in cells. 相似文献
65.
66.
67.
S Stagno D W Reynolds E S Huang S D Thames R J Smith C A Alford 《The New England journal of medicine》1977,296(22):1254-1258
The overall prevalence of congenital cytomegalovirus infection among the offspring of a highly immune young female population was 2.4 per cent (23 of 939). To ascertain whether the presence of anticytomegalovirus antibodies protects the developing fetus, we examined the offspring of 239 prospectively studied women. Despite substantial levels of preconceptional antibodies, intrauterine cytomegalovirus infection occured in seven of 208 (3.4 per cent) seroimmune women. Three neonates with congenital infection were born to 31 initially seronegative women. All the congenitally infected infants had subclinical involvement. Maternal humoral immunity may not protect the fetus against congenital cytomegalovirus infection. Neutralization kinetics and restriction enzyme analysis with endonucleases (EcoR-1 and HinD 111) demonstrated antigenic and genetic homology between viral strains isolated from two siblings consecutively infected in utero, indicating that repeat maternal infection with the same virus is transmissible to sequential products of conception. 相似文献
68.
Summary The development of the neocortex has previously been extensively studied in carnivores (cat and ferret), rodents (rat and mouse) and primates (monkey and human). In these species, it has been shown that the initial population of cells migrating from the ventricular zone forms the primordial plexiform layer. This is subsequently split into marginal zone and subplate zone by the insertion of later-migrating cells into the primordial plexiform layer, to form the cortical plate proper. Many of the cells derived from the split primordial plexiform layer are transient. The neurons of the subplate zone are found in the deeper part of layer VI, and white matter deep to layer VI in the more mature cortex; most of these neurons disappear by adulthood. [3H]-thymidine labelling in the present study has shown a similar pattern of neocortical development in Artiodactyla (sheep). In addition it has been shown that the previously described staining of subplate and cortical plate cells for the fetal protein fetuin indicates that fetuin is a useful marker for a proportion of this transient population of neurons and defines its extent in neocortical development more clearly. Dividing cells were labelled by a single intra-amniotic injection of [3H]-thymidine at E26 to E35 (birth is at E150). The brains were subsequently examined at E40 or E80 for [3H]-thymidine labelling and fetuin staining by a combination of autoradiography and immunocytochemistry. The earliest generated neocortical cells detected in this study (E26) were found in two layers by E40, the outer marginal zone and inner subplate zone. Neurons of the marginal zone were generated up to E28; those of the early subplate zone were generated up to E31. The cortical plate proper was generated by cells born on E32 and later. This sequence is similar to that described in other species, especially the cat. A proportion of the early-generated neurons in the marginal zone, subplate zone and early cortical plate stained for fetuin. By E80 these earliest-generated, fetuin-positive cells were found in the white matter deep to the forming neocortical layers and in layer VI. In adult brains no fetuin-positive neurons could be identified in the neocortex, and neurons had almost entirely disappeared from the white matter. The fetal glycoprotein fetuin seems to be specifically associated with a population of cells that has the same developmental history as the transient marginal zone and subplate neurons described in other species. However, the distribution of fetuin-containing neurons is more extensive and includes some of the neurons within the cortical plate itself. Thus in addition to being a marker for a proportion of the transient marginal zone and subplate cells, the presence of fetuin in subplate and cortical plate neurons, given the trophic properties attributed to fetuin, may indicate its involvement in early stages of synaptogenesis and connectivity in the developing neocortex. 相似文献
69.
Hall M Buysse DJ Nowell PD Nofzinger EA Houck P Reynolds CF Kupfer DJ 《Psychosomatic medicine》2000,62(2):227-230
OBJECTIVE: Previous studies have not evaluated the clinical correlates of the electroencephalographic spectral profile in patients with insomnia. In the preliminary study described here, we evaluated the extent to which symptoms of stress and depression are associated with subjective sleep complaints and quantitative measures of sleep in individuals with chronic insomnia. METHODS: Subjects were 14 healthy adults who met criteria for primary insomnia as specified in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders. Measures of stress, depression, and subjective sleep quality were collected before subjects participated in a two-night laboratory sleep series. We hypothesized that elevated symptoms of stress and depression would be associated with subjective sleep complaints and electroencephalographic evidence of hyperarousal during sleep. Hyperarousal during sleep was defined as decreases in delta power and elevations in alpha and beta power throughout non-rapid eye movement sleep, and symptoms of stress were defined as the tendency to experience stress-related intrusive thoughts and the interaction between intrusion tendency and the number of recent stressful events (subjective stress burden). RESULTS: A stronger tendency to experience stress-related intrusive thoughts was associated with greater sleep complaints and a trend toward higher beta power, whereas increases in subjective stress burden were associated with decreases in delta power. In addition, elevations in subclinical symptoms of depression were associated with greater sleep complaints and elevations in alpha power. CONCLUSIONS: Observed relationships among symptoms of stress, depression, subjective sleep complaints, and electroencephalographic power may be relevant to the discrepancy between subjective and objective measures of sleep in patients with insomnia and may be more broadly applicable to sleep complaints in association with stressful life events and major depression. 相似文献
70.
Cohn R Trouth AJ Dawoodi K Rahming C Reynolds S 《Electromyography and clinical neurophysiology》2001,41(3):131-136
Paroxysmal bi-parietal (vertex) discharges are evoked during sleep by full field stroboscopic light stimulation in approximately 20 per cent of children with a diagnosis of various seizure phenomena. 相似文献