全文获取类型
收费全文 | 14741篇 |
免费 | 1180篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 169篇 |
儿科学 | 521篇 |
妇产科学 | 294篇 |
基础医学 | 2328篇 |
口腔科学 | 359篇 |
临床医学 | 1508篇 |
内科学 | 3133篇 |
皮肤病学 | 248篇 |
神经病学 | 1082篇 |
特种医学 | 559篇 |
外国民族医学 | 1篇 |
外科学 | 2009篇 |
综合类 | 127篇 |
一般理论 | 8篇 |
预防医学 | 1143篇 |
眼科学 | 325篇 |
药学 | 1176篇 |
中国医学 | 15篇 |
肿瘤学 | 962篇 |
出版年
2022年 | 116篇 |
2021年 | 224篇 |
2020年 | 195篇 |
2019年 | 248篇 |
2018年 | 273篇 |
2017年 | 266篇 |
2016年 | 311篇 |
2015年 | 284篇 |
2014年 | 407篇 |
2013年 | 546篇 |
2012年 | 710篇 |
2011年 | 665篇 |
2010年 | 412篇 |
2009年 | 384篇 |
2008年 | 570篇 |
2007年 | 618篇 |
2006年 | 556篇 |
2005年 | 538篇 |
2004年 | 604篇 |
2003年 | 500篇 |
2002年 | 488篇 |
2001年 | 425篇 |
2000年 | 469篇 |
1999年 | 418篇 |
1998年 | 205篇 |
1997年 | 167篇 |
1996年 | 183篇 |
1995年 | 159篇 |
1994年 | 156篇 |
1993年 | 149篇 |
1992年 | 305篇 |
1991年 | 338篇 |
1990年 | 335篇 |
1989年 | 360篇 |
1988年 | 277篇 |
1987年 | 287篇 |
1986年 | 244篇 |
1985年 | 294篇 |
1984年 | 195篇 |
1983年 | 171篇 |
1982年 | 129篇 |
1981年 | 108篇 |
1980年 | 99篇 |
1979年 | 167篇 |
1978年 | 126篇 |
1977年 | 108篇 |
1975年 | 99篇 |
1974年 | 117篇 |
1973年 | 105篇 |
1972年 | 86篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
J J Hansen B Nielsen P Krogsgaard-Larsen L Brehm E O Nielsen D R Curtis 《Journal of medicinal chemistry》1989,32(10):2254-2260
The enantiomers of alpha-amino-4-bromo-3-hydroxy-5-isoxazolepropionic acid (4-bromohomoibotenic acid, Br-HIBO, 1) a selective and potent agonist at one class of the central (S)-glutamic acid receptors, were prepared with an enantiomeric excess higher than 98.8% via stereoselective enzymic hydrolysis of (RS)-alpha-(acetylamino)-4-bromo-3-methoxy-5-isoxazolepropionic acid (4) using immobilized aminoacylase. The absolute configuration of the enantiomers of Br-HIBO was established by X-ray crystallographic analysis, which confirmed the expected preference of the enzyme for the S form of the substrate 4. (S)- and (RS)-Br-HIBO were potent neuroexcitants on cat spinal neurones in vivo, while (R)-Br-HIBO was a very weak excitant. Correspondingly, the S enantiomer of Br-HIBO (IC50 = 0.34 microM) was considerably more potent than the R form (IC50 = 32 microM) as an inhibitor of [3H]-(RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid ([ 3H]AMPA) binding to rat brain synaptic membranes in vitro. In contrast, (S)- and (R)-Br-HIBO were approximately equipotent (IC50 values of 0.22 and 0.15 microM, respectively) as inhibitors of [3H]-(S)-glutamic acid binding in the presence of CaCl2. The enantiomers of Br-HIBO showed no significant affinity for those binding sites on rat brain membranes which are labeled by [3H]kainic acid or [3H]-(R)-aspartic acid. 相似文献
82.
83.
Acute phase reaction, heterogeneity, and microheterogeneity of serum proteins as nonspecific tumor markers in lung cancer 总被引:2,自引:0,他引:2
The acute phase proteins, orosomucoid, ceruloplasmin, antitrypsin, and haptoglobin were measured in serum from 54 patients with lung cancer, 16 patients with benign lung inflammation, and 30 healthy individuals. A statistical correlation was found between tumor size and acute phase protein level, which, however, was ascribed to nonspecific inflammation in the tissues surrounding the tumor. The patients who subsequently could not be radically treated by surgery had higher concentrations of orosomucoid and ceruloplasmin than the radically treated patients. No difference in acute phase protein concentration was found between benign and malignant disease. The glycan-dependent microheterogeneity of orosomucoid and ceruloplasmin was analyzed by crossed affinoimmunoelectrophoresis with lectins, and the patterns of the patients with benign inflammation and malignant disease were different. The heterogeneity of ceruloplasmin was also analyzed by crossed immunoelectrophoresis without lectin. This analysis, combined with the total serum concentration of ceruloplasmin, made it possible to discriminate the 54 cases of malignancy from the 46 cases of nonmalignancy with a sensitivity of 78% and a specificity of 93%. It is suggested that the simple electrophoretic analyses of (micro-)heterogeneity is a valuable supplement to the acute phase profile in isolating high-risk patients and in monitoring radically treated cancer patients for relapse. 相似文献
84.
85.
86.
C. A. Guldberg A. A. Dahl A. Bertelsen H. Hansen J. Haslerud K. Hytten K. Narud 《Acta psychiatrica Scandinavica》1996,93(2):113-118
The ICD-10 and DSM-IV classifications have both given low priority to “reactivity” to acute stress as a classificatory principle for functional psychoses. In Scandinavia, reactivity is still considered an important factor in the development of such psychoses. Reactivity is a complex concept, and its various components are historically examined. The Reactivity of Psychosis Rating Form (RPRF) was developed in order to operationalize reactivity. Seven of the 10 elements of RPRF can be rated reliably. Factor analysis of the RPRF yields three factors: stressor, onset and change, that also show high interrater reliability. Our results indicate that RPRF has both construct and discriminant validity. Further studies with the RPRF may elucidate the true status of reactivity in functional psychoses. 相似文献
87.
Per Karlsson Lars Farde Christer Halldin Carl-Gunnar Swahn Göran Sedvall Christian Foged Kristian Tage Hansen Birte Skrumsager 《Psychopharmacology》1993,113(2):149-156
The benzazepines NNC 687 and NNC 756 have in animal studies been described as selective D1-dopamine receptor antagonists. Both compounds have been labeled with11C for examination by positron emission tomography (PET). In the present study central receptor binding was studied in monkeys and healthy men. After IV injection of both radioligands in Cynomolgus monkeys radioactivity accumulated markedly in the striatum, a region with a high density of D1-dopamine receptors. This striatal uptake was displaced by high doses of the selective D1-antagonist SCH 23390 (2 mg/kg) but not by the 5HT2-antagonist ketanserin (1.5 mg/kg) or the selective D2-antagonist raclopride (3 mg/kg). The cortical uptake after injection of [11C]NNC 687 was not reduced in displacement experiments with ketanserin. The cortical uptake of [11C]NNC 756 was reduced in displacement and protection experiments with ketanserin by 24–28% (1.5 mg/kg), whereas no reduction could be demonstrated on striatal uptake. In healthy males both compounds accumulated markedly in the striatum. For [11C]NNC 687 the ratio of radioactivity in the putamen to cerebellum was about 1.5. For [11C]NNC 756 the ratio was about 5. This ratio of 5 for [11C]NNC 756 is the highest obtained so far for PET radioligands for the D1-dopamine receptor. 相似文献
88.
Henrik Husted S ren Overgaard Jens Ole Laursen Klaus Hinds Lise N rrekjaer Hansen Harald M. Knudsen Niels B. Mossing 《Acta orthopaedica》1996,67(5):421-423
During the 10-year period 1981-1990, 1, 199 patients in the county of South Jutland, Denmark, had 1, 477 primary total hip arthroplasties (THA) performed because of primary arthrosis (OA).
The patients were followed until the end of 1994, with a mean follow-up of 5.6 (0-14) years. Bilateral operations were performed on 356 patients, whereas 248 patients had died with only 1 THA.
The cumulated risk of replacement of the contralateral hip was approximately 0.15 1 year after replacement of the first hip, 0.20 after 2 years, 0.29 after 5 years and 0.47 after 10 years, respectively.
During the follow-up period, the demand for a THA of the contralateral hip continued to be approximately 15 times higher than in the general population. 相似文献
The patients were followed until the end of 1994, with a mean follow-up of 5.6 (0-14) years. Bilateral operations were performed on 356 patients, whereas 248 patients had died with only 1 THA.
The cumulated risk of replacement of the contralateral hip was approximately 0.15 1 year after replacement of the first hip, 0.20 after 2 years, 0.29 after 5 years and 0.47 after 10 years, respectively.
During the follow-up period, the demand for a THA of the contralateral hip continued to be approximately 15 times higher than in the general population. 相似文献
89.
Spontaneous remission in a patient with therapy-related myelodysplastic syndrome (t-MDS) with monosomy 7 总被引:1,自引:0,他引:1
B. Renneboog V. Hansen P. Heimann A. De Mulder F. Janssen & A. Ferster 《British journal of haematology》1996,92(3):696-698
We describe a case of spontaneously reversible refractory anaemia, a subtype of myelodysplastic syndrome (MDS), with monosomy 7 secondary to chronic treatment with azathioprine (AZA) in a young renal transplant recipient. AZA was stopped after that conventional cytogenetics and fluorescence in situ hybridization (FISH) had demonstrated the existence of a monosomy 7 clone. 4 months later, haematological values had considerably improved and the karyotypic examination as well as the FISH analysis were normal. The spontaneous remission of this MDS with monosomy 7, which is usually associated with a particularly poor prognosis, could be due to the recovery of a better immunosurveillance following the withdrawal of AZA. 相似文献
90.
E K Hansen 《Scandinavian journal of dental research》1992,100(6):305-309
Dentin hypersensitivity in 112 teeth was randomly treated with Duraphat or Vitrabond. No patients were included unless they, without being asked, complained about daily pain for a long period of time caused by cold, warm, sweet, sour, touch or any combination of these five variables. Patients were excluded if the dentin hypersensitivity could have been caused by cervical abrasion/erosion lesions deeper than 1 mm, cracked-tooth syndrome, caries lesions, operative caries treatment, and/or periodontal surgery or root scaling within the last 6 months. The pain was registered on a binary scale: 1) pain before the treatment; and 2) pain/no pain after the treatment. With Duraphat, 22% of the treatments failed within 1 wk and the cumulative 1-yr success rate was 41%. With Vitrabond, 2% failed within the first week and the 1-yr success rate was 79%. The difference between the two treatments was highly significant. Patients in whom Duraphat failed were treated with Vitrabond and vice versa; the 1-yr success rate for the retreated teeth was 68% when "Duraphat-failures" were treated with Vitrabond and 42% when "Vitrabond-failures" were treated with Duraphat. 相似文献