全文获取类型
收费全文 | 220979篇 |
免费 | 17022篇 |
国内免费 | 7143篇 |
专业分类
耳鼻咽喉 | 1257篇 |
儿科学 | 7657篇 |
妇产科学 | 1550篇 |
基础医学 | 19483篇 |
口腔科学 | 3609篇 |
临床医学 | 23378篇 |
内科学 | 55907篇 |
皮肤病学 | 2717篇 |
神经病学 | 26130篇 |
特种医学 | 6323篇 |
外国民族医学 | 4篇 |
外科学 | 16789篇 |
综合类 | 30023篇 |
现状与发展 | 31篇 |
一般理论 | 9篇 |
预防医学 | 18675篇 |
眼科学 | 2391篇 |
药学 | 15214篇 |
196篇 | |
中国医学 | 10060篇 |
肿瘤学 | 3741篇 |
出版年
2024年 | 682篇 |
2023年 | 4652篇 |
2022年 | 8357篇 |
2021年 | 11855篇 |
2020年 | 11093篇 |
2019年 | 8465篇 |
2018年 | 8320篇 |
2017年 | 8233篇 |
2016年 | 8551篇 |
2015年 | 8246篇 |
2014年 | 15596篇 |
2013年 | 17026篇 |
2012年 | 12730篇 |
2011年 | 13772篇 |
2010年 | 10849篇 |
2009年 | 10431篇 |
2008年 | 10432篇 |
2007年 | 10092篇 |
2006年 | 8987篇 |
2005年 | 7414篇 |
2004年 | 6306篇 |
2003年 | 5422篇 |
2002年 | 4575篇 |
2001年 | 3950篇 |
2000年 | 3296篇 |
1999年 | 2819篇 |
1998年 | 2701篇 |
1997年 | 2382篇 |
1996年 | 2134篇 |
1995年 | 1928篇 |
1994年 | 1774篇 |
1993年 | 1515篇 |
1992年 | 1453篇 |
1991年 | 1278篇 |
1990年 | 1011篇 |
1989年 | 858篇 |
1988年 | 805篇 |
1987年 | 732篇 |
1986年 | 633篇 |
1985年 | 736篇 |
1984年 | 617篇 |
1983年 | 380篇 |
1982年 | 446篇 |
1981年 | 374篇 |
1980年 | 282篇 |
1979年 | 247篇 |
1978年 | 184篇 |
1977年 | 164篇 |
1976年 | 135篇 |
1975年 | 49篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Data on 232 members of a single pedigree, descended from two pairs of original parents, were made available to the participants of Genetic Analysis Workshop 8 (GAW8). In addition to information concerning age and sex, measurements for 10 quantitative traits and genotypes at 22 polymorphic marker loci were also provided for a subset of 193 of these family members. © 1993 Wiley-Liss, Inc. 相似文献
22.
R. N. KALARIA ‡‡ P. G. GALLOWAY† G. PERRY‡ ‡‡ 《Neuropathology and applied neurobiology》1991,17(3):189-201
Amyloid P (AP) component is present in all types of systemic amyloid deposits. Recently, it has been shown to be also present in cerebral amyloid lesions of Alzheimer's disease (AD). In this study, we used immunocytochemical methods to extend these findings at the electron microscope level and characterize the spectrum of AP immunoreactivity in neurofibrillary pathology (NFP) of AD and other neurodegenerative disorders including Down's syndrome (DS), Creutzfeldt-Jakob, Parkinson's, Pick's and diffuse Lewy body diseases and progressive supranuclear palsy. In AD and DS, AP immunoreaction product was evident in all the classical amyloid lesions and NFP in a large sample of all cortical areas examined. The distribution and relative intensity of immunostaining was similar to that of thioflavin S staining in serial sections. In many cases, however, plaques and vessels stained by anti-AP serum were not apparent with thioflavin S. Serial sections immunostained with antiserum to amyloid A, C-reactive protein or to other proteins involved in systemic amyloidoses and the acute phase response showed no evidence of staining in any of the cerebral lesions. Electron microscopy confirmed that AP immunoreactivity was associated with the abnormal filaments characteristic of NFP as well as amyloid fibrils found in plaques and vessels showing congophilic amyloid angiopathy. Plaques of Creutzfeldt-Jakob disease, Pick bodies of Pick's disease, tangles and Lewy bodies in Parkinson's disease and a subpopulation of Lewy bodies in the diffuse Lewy body disease coexistent with AD were also stained. With the exception of vessels in two of the five cases, AP was not detected in age-matched controls. Our observations indicate AP to be a consistent feature of cerebral NFP and amyloid deposits. 相似文献
23.
Neuropsychiatric disturbances are extremely common in Alzheimer’s disease (AD), and represent integral features of the illness,
as well as appropriate targets for therapy. We are interested in designing trials aimed at preventing or delaying the emergence
of psychopathology in AD. For symptomatic treatment of agitation, mood stabilizers, particularly sodium valproate, have proved
to be beneficial in some patients. Since these effects take several weeks to emerge, we considered that they might be dependent
on potentially neuroprotective actions of valproate, such as inhibition of apoptosis and slowing of neurofibrillary tangle
formation. In this article we present the rationale for testing the neuroprotective potential of valproate experimentally
in mouse models of tauopathy and in a clinical trial of patients with AD who lack psychopathology at baseline. Together, these
studies will provide important tests of the hypothesis that valproate, either through inhibition of tau phosphorylation or
some other mechanism, is a useful therapeutic agent to modify disease progression in AD. 相似文献
24.
M. D. Taylor M. L. de Ceballos S. Rose P. N. Chong P. Jenner C. D. Marsden 《Journal of neural transmission (Vienna, Austria : 1996)》1991,3(2):99-108
Summary Aged common marmosets were treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 0.5–2.0 mg/kg/week i.p.) for 16 or 24 weeks, observed for a total of 30 weeks and then killed for measurement of biochemical pramaters in basal ganglia. The MPTP treatment induced a marked depletion in dopamine, 3,4-dihydroxyphenylacetic acid and homovanillic acid levels in the caudate nucleus and putamen. In contrast, the concentrations of five neuropeptides: [Met5]-enkephalin, [Leu5]-enkephalin, cholecystokinin, substance P and neurotensin as measured by a combined HPLC/RIA method, remained unaltered in all basal ganglia regions examined. Enkephalin precursor levels, as reflected by cryptic [Met5]-enkephalin content, were increased in the putamen, but not in the caudate nucleus, as a consequence of MPTP administration. Cryptic [Leu5]-enkephalin content remained unchanged in the striatum of MPTP treated marmosets. Overall, these results suggest an increase in striatal [Met5]-enkephalin release following chronic MPTP treatment of aged marmosets. However, the chronic treatment of aged marmosets with MPTP does not reproduce the neuropeptide alterations characteristic of Parkinson's disease. 相似文献
25.
Directors of nursing at 23 nursing homes with Alzheimer's units in Southwestern Pennsylvania completed a self‐reported survey of 12 questions. Responses from the self‐administered questionnaires (100% response rate) revealed a wide variation in the staff categories assessing the oral health status of newly admitted residents with AD. The respondents described oral examinations that were incomplete when compared to the oral indicators listed in the Minimum Data Set. All nursing homes reported that oral hygiene was provided each day. The number of residents in a facility had a significant effect on the frequency of oral hygiene provided. Only 52% of the facilities reported yearly oral examinations for this population. According to the respondents, dental treatment was typically performed on‐site. The oral health care costs were paid by Medicare, Medicaid, the residents/family members, or by other undescribed resources. Insufficient time, staff, and training, as well as uncooperative behavior, were identified as barriers to optimum oral health care for residents with AD. Additional staff, specialized training, and increased government reimbursement were suggested to improve the oral health care for this group of older adults. For future studies, review of medical records and on‐site evaluation of the oral health care at these facilities should be required to verify the reported practices. 相似文献
26.
Summary This study was undertaken to elucidate, using the Golgi method, the neuropathological change in the brain of the macular mutant mouse, whose hemizygote (Ml/y) is considered to be a model of Menkes kinky hair disease (MKHD). The hemizygote mice gradually lost weight after 10 days of age and died with emaciation and seizure around day 15. The normal littermate (+/y) was well developed. In the cerebrum, the arborization of pyramidal neurons in the layer V of the Ml/y was the same as that in the +/y on day 10. However, development of arborization in the Ml/y was delayed in comparison with that in the +/y on days 12 and 14. Purkinje cells with several somal sprouts were observed in the cerebellum in both the Ml/y and +/y on day 7. The somal sprouts in the +/y had regressed gradually by day 12, while they were still in the anterior and middle lobes of the Ml/y on day 14. Additionally, the trunks of Ml/y stem dendrites became thicker and a cactus formation was recognized on the branching portion of the dendrites on day 14. Arborization of these abnormal Purkinje cells was distinctly poor compared with that in the +/y. These results suggest that the growth of the neurons is delayed in the Ml/y and simultaneously their cytoskeletal developments are disturbed, especially in the Purkinje cells. There is a close similarity in many respects to the neuropathological change in MKHD. 相似文献
27.
X Dong M He X Song B Lu Y Yang S Zhang N Zhao L Zhou Y Li X Zhu R Hu 《Diabetic medicine》2007,24(12):1482-1486
AIMS: Our aim was to assess performances of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease (MDRD) formulae in estimating glomerular filtration rate (GFR) in Chinese diabetic populations and their association with vascular risks. METHODS: A total of 1009 patients with Type 2 diabetes were categorized into low estimated GFR groups (GFR < 60 ml/min/1.73 m(2)) and control groups by the two equations. The performances of these formulae were assessed at different stages of kidney function. Carotid artery intima-media thickness (IMT) and the prevalence of diabetic retinopathy or albuminuria were compared among the groups. The ability of these formulae to identify established vascular risk markers using sensitivity, specificity, positive and negative predictive values were also compared. RESULTS: The prevalence of low estimated GFR was 32.7% with the Cockcroft-Gault formula and 5.2% with the MDRD formula, respectively. In low estimated GFR subjects by the MDRD formula, IMT was significantly thicker than those by the Cockcroft-Gault formula (1.2 mm vs. 1.0 mm; P < 0.05), with a higher prevalence of albuminuria (78.4 vs. 52.8%, P < 0.05) and diabetic retinopathy (46.5 vs. 30.5%; P < 0.05). The Cockcroft-Gault formula gave a specificity of 71.7% and a sensitivity of 37.0%, and the MDRD formula gave a specificity of 96.6% and a sensitivity of 7.9% in estimating low GFR relevant for established vascular risks. CONCLUSIONS: These formulae performed differently in Chinese diabetic populations. The simplified MDRD formula is minimally superior to the Cockcroft-Gault formula for its high specificity and positive predictive values in estimating low GFR relevant for vascular risks. 相似文献
28.
29.
目的 研究利福昔明对比环丙沙星治疗急性肠炎的有效性和安全性。 方法 采用随机对照方法 ,共治疗 5 1例急性肠炎。利福昔明治疗 2 5例 ,环丙沙星 2 6例 ,用药时间方法相同。观察治疗前后临床症状、大便性状、大便次数、便常规、血常规、尿常规及肝肾功能 ,以了解其疗效及不良反应情况。 结果 利福昔明组 (治疗组 )与环丙沙星组 (对照组 )相比 ,显效率分别为 92 .0 %和 80 .8% ,总有效率分别为 92 .0 %和 96 .2 % ,止泻时间治疗组 2 8.6 7± 15 .92h ,对照组 36 .12± 2 0 .70h ,均未见明显毒副作用。以上各项指标及两组在治疗过程中大便次数变化、大便常规复常率经统计学处理均无显著性差异 (P >0 0 5 )。 结论 利福昔明可用于治疗急性肠炎 ,与环丙沙星比较 ,疗效相仿 ,但耐受性好 ,口服不吸收 ,故值得推广 相似文献
30.
Keijiro Sunada Hironori Yamamoto Hiroto Kita Tomonori Yano Tomohiko Miyata Yutaka Sekine Akiko Kuno Nobuki Onishi Michiko Iwamoto Atsuhiro Sasaki Kenichi Ido Kentaro Sugano 《Digestive endoscopy》2004,16(3):237-240
The requirement for endoscopic access to a stricture is a major limitation of the endoscopic dilatation for the treatment of strictures in the gastrointestinal tract. We have developed the double‐balloon enteroscopy method that enables visualization of the entire small bowel. In addition, double‐balloon enteroscopy has a potential for the interventional therapy including dilatation of strictures. We present here a case of jejunal strictures in a 47‐year‐old woman with Crohn's disease successfully treated with a balloon catheter in combination with double‐balloon enteroscopy. Balloon dilation with double‐balloon enteroscopy is a promising method for the treatment of small bowel strictures in Crohn's disease. 相似文献