全文获取类型
收费全文 | 14631篇 |
免费 | 1195篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 170篇 |
儿科学 | 491篇 |
妇产科学 | 300篇 |
基础医学 | 2329篇 |
口腔科学 | 353篇 |
临床医学 | 1473篇 |
内科学 | 3121篇 |
皮肤病学 | 247篇 |
神经病学 | 1128篇 |
特种医学 | 482篇 |
外国民族医学 | 1篇 |
外科学 | 2000篇 |
综合类 | 96篇 |
一般理论 | 8篇 |
预防医学 | 1155篇 |
眼科学 | 345篇 |
药学 | 1172篇 |
中国医学 | 17篇 |
肿瘤学 | 968篇 |
出版年
2022年 | 120篇 |
2021年 | 238篇 |
2020年 | 204篇 |
2019年 | 259篇 |
2018年 | 282篇 |
2017年 | 271篇 |
2016年 | 323篇 |
2015年 | 289篇 |
2014年 | 410篇 |
2013年 | 543篇 |
2012年 | 724篇 |
2011年 | 679篇 |
2010年 | 401篇 |
2009年 | 374篇 |
2008年 | 573篇 |
2007年 | 631篇 |
2006年 | 559篇 |
2005年 | 558篇 |
2004年 | 618篇 |
2003年 | 506篇 |
2002年 | 492篇 |
2001年 | 423篇 |
2000年 | 464篇 |
1999年 | 406篇 |
1998年 | 186篇 |
1997年 | 144篇 |
1996年 | 160篇 |
1995年 | 142篇 |
1994年 | 138篇 |
1993年 | 134篇 |
1992年 | 305篇 |
1991年 | 334篇 |
1990年 | 329篇 |
1989年 | 339篇 |
1988年 | 262篇 |
1987年 | 275篇 |
1986年 | 236篇 |
1985年 | 288篇 |
1984年 | 191篇 |
1983年 | 164篇 |
1982年 | 126篇 |
1981年 | 102篇 |
1980年 | 89篇 |
1979年 | 165篇 |
1978年 | 122篇 |
1977年 | 106篇 |
1975年 | 97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
71.
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
72.
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
73.
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
74.
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
75.
H Henkes S Kubicki M L Hansen K Terstegge G Scholz M Ruhnke 《EEG-EMG Zeitschrift für Elektroenzephalographie, Elektromyographie und verwandte Gebiete》1989,20(4):295-301
Polysomnograms were recorded of twelve patients with acquired immune deficiency syndrome (AIDS) during different stages in an open design. During the first night no hypnotics were administered, during the second night 30 mg flurazepam per os were given. Flurazepam affected mainly the NREM parameters. The times "awake" during the night were reduced, sleep stage 2 showed an increase, and the effective sleep time was also increased. The increase in sleep spindle density was remarkable, however, delta sleep and generation of K-complexes were not affected. Flurazepam did not affect REM sleep at all. The amount of REM sleep showed a slight increase. REM distribution during the night did not show the "bell shaped" increase and the decrease in the morning; the degree of the illness correlated with a flattening of REM distribution. 相似文献
76.
While previous studies have identified a protective effect for barbiturate anesthesia during focal cerebral ischemia, no such effect has been demonstrated for isoflurane. To better understand the effects of these anesthetics on cerebral blood flow and metabolism that might have relevance to their respective potential for cerebral protection, fasted physiologically stable rats underwent autoradiographic determination of CBF and CMRglu during deep isoflurane or pentobarbital anesthesia (burst suppression of EEG). As expected, cerebral blood flow was significantly greater during isoflurane anesthesia (isoflurane = 157 +/- 18 and pentobarbital = 54 +/- 12 ml/100 g/min) while CMRglu values were nearly identical (isoflurane = 35 +/- 5 and pentobarbital = 33 +/- 4 mumol/100 g/min). Additional identically anesthetized rats underwent middle cerebral artery occlusion with CBF autoradiographically determined 1 h later. While the insult resulted in a significant reduction in the ipsilateral hemispheric and cortical blood flow in both anesthetic groups, flow remained at least twofold greater in isoflurane as opposed to pentobarbital-anesthetized rats. When regional flow was assessed, no difference between groups was observed with respect to the area of tissue with flow values falling between 0-10 ml/100 g/min. In contrast, isoflurane-anesthetized rats had significantly less hemispheric and cortical area with flow values in the ranges of 10-20 and 20-30 ml/100 g/min, respectively. These data, therefore, do not support the contention that isoflurane causes maldistribution of CBF during focal ischemia. 相似文献
77.
Bartholdy C Stryhn A Hansen NJ Buus S Thomsen AR 《European journal of immunology》2003,33(7):1941-1948
DNA vaccination is an efficient way to induce CD8+ T cell memory, but it is still unclear to what extent such memory responses afford protection in vivo. To study this, we induced CD8+ memory responses directed towards defined viral epitopes, using DNA vaccines encoding immunodominant MHC class I-restricted epitopes of lymphocytic choriomeningitis virus covalently linked to beta2-microglobulin. This vaccine construct primed for a stronger recall response than did a more conventional minigene construct. Despite this, vaccinated mice were only protected against systemic infection whereas protection against the consequences of peripheral challenge was limited. Phenotypic analysis revealed that DNA vaccine-primed CD8+ T cells in uninfected mice differed from virus-primed CD8+ T cells particularly regarding expression of very-late antigen (VLA)-4, an adhesion molecule important for targeting T cells to inflammatory sites. Thus, our DNA vaccine induces a long-lived memory CD8+ T cell population that provides efficient protection against high-dose systemic infection. However, viral replication in solid non-lymphoid organs is not curtailed sufficiently fast to prevent significant virus-induced inflammation. Our results suggest that this is due to qualitative limitations of the primed CD8+ T cells. 相似文献
78.
Taste buds are chemosensory endorgans consisting of modified epithelial cells. Fish and other vertebrates use their taste bud cells to sample potential food, either selecting or rejecting substances according to their edibility. The adult gustatory system in fish has been studied thoroughly, including regeneration experiments. Taste buds occur in the epithelia of the lips, the mouth cavity, the oropharyngeal cavity, and also in the skin of the barbels, the head, and sometimes even all over the body surface. Despite its importance for feeding, little is known about the ontogeny of the fish taste system. We examined the development of taste buds in the zebrafish on the light microscopical and the scanning and transmission electron microscopical levels. Taste buds develop later than the olfactory organ and the solitary chemosensory cells, two other chemosensory systems in aquatic vertebrates. The first few taste bud primordia are visible within the epithelia of lips and gill arches 3 to 4 days after fertilization, and the first few taste buds with open receptor areas appear on the lips and simultaneously on the gill arches 4-5 days after fertilization, which coincides with the onset of feeding. Taste buds in the mouth cavity, on the head, and on the barbels are formed later in development. As seen in other fish, zebrafish taste buds contain elongate dark and light cells, termed according to their electron density. Dark cells with a cell apex of many short microvilli appear first, followed by the light cells with one large microvillus. In addition, the zebrafish has a third fusiform cell type, which appears last. This cell type is low in electron density and has a brush-like apical ending with several small microvilli. This cell type has not been described previously. Furthermore, in zebrafish, the ontogenetic processes of taste bud formation differ from regenerative processes described in the literature. 相似文献
79.
J G Schwartz N Clare K Hansen H Britton L Manhoff 《Cancer Genetics and Cytogenetics》1986,20(1-2):89-93
A 4-year-old female with acute promyelocytic leukemia (APL) was found to have a variant form of the 15;17 translocation, which is diagnostic of APL. The karyotype of the malignant cells was 47,XX,t(1;11)(q25;q21),t(1;17)(p36;q21), + 8. This case is additional evidence that the breakpoint of #17 at q21 is the characteristic chromosomal aberration of APL. The present case is also unusual because of the young age of the patient. 相似文献
80.
Heterozygote detection in phenylketonuria 总被引:1,自引:0,他引:1
Phenylalanine loading was carried out on 105 parents of children with phenylalanine hydroxylase deficiency and 33 apparently normal individuals with no family history of phenylketonuria. The best discriminant was found to be the logarithmic transformation of the slope of the rise in serum tyrosine multiplied by the maximum serum tyrosine concentration over the maximum serum phenylalanine concentration obtained after an oral load with a pure solution of L-phenylalanine. The overlap between heterozygotes for phenylketonuria and normal homozygotes was 2.4%. The distribution of the discriminant values suggested three heterozygous phenotypes for phenylalanine hydroxylase deficiency, and the phenotypic combination of parents could be correlated to the phenotype of their affected offspring, i.e. classical phenylketonuria, mild phenylketonuria or hyperphenylalaninemia. The probability of heterozygosity for phenylketonuria was determined by means of the distribution of the discriminant values of the heterozygotes and that of normal homozygotes. The likelihood of being a heterozygote was corrected for the genetic background of the person requiring genetic counseling, and was finally expressed as the percentage probability of being a heterozygote for phenylketonuria. 相似文献