全文获取类型
收费全文 | 430052篇 |
免费 | 43580篇 |
国内免费 | 3006篇 |
专业分类
耳鼻咽喉 | 8617篇 |
儿科学 | 13938篇 |
妇产科学 | 8556篇 |
基础医学 | 42990篇 |
口腔科学 | 7912篇 |
临床医学 | 49514篇 |
内科学 | 108502篇 |
皮肤病学 | 14355篇 |
神经病学 | 39668篇 |
特种医学 | 14825篇 |
外国民族医学 | 106篇 |
外科学 | 74550篇 |
综合类 | 1860篇 |
现状与发展 | 72篇 |
一般理论 | 90篇 |
预防医学 | 33589篇 |
眼科学 | 8687篇 |
药学 | 20303篇 |
中国医学 | 833篇 |
肿瘤学 | 27671篇 |
出版年
2023年 | 6110篇 |
2022年 | 2807篇 |
2021年 | 7906篇 |
2020年 | 8578篇 |
2019年 | 7097篇 |
2018年 | 16893篇 |
2017年 | 13411篇 |
2016年 | 13925篇 |
2015年 | 14432篇 |
2014年 | 22462篇 |
2013年 | 26635篇 |
2012年 | 24094篇 |
2011年 | 24321篇 |
2010年 | 19865篇 |
2009年 | 21697篇 |
2008年 | 21959篇 |
2007年 | 21242篇 |
2006年 | 22366篇 |
2005年 | 19600篇 |
2004年 | 17965篇 |
2003年 | 15736篇 |
2002年 | 15021篇 |
2001年 | 10745篇 |
2000年 | 10091篇 |
1999年 | 9513篇 |
1998年 | 5130篇 |
1997年 | 4618篇 |
1996年 | 4416篇 |
1995年 | 4162篇 |
1994年 | 2777篇 |
1993年 | 2327篇 |
1992年 | 4992篇 |
1991年 | 4606篇 |
1990年 | 4137篇 |
1989年 | 4001篇 |
1988年 | 3626篇 |
1987年 | 3331篇 |
1986年 | 3211篇 |
1985年 | 2837篇 |
1984年 | 2149篇 |
1983年 | 1897篇 |
1982年 | 1340篇 |
1979年 | 1696篇 |
1978年 | 1336篇 |
1977年 | 1329篇 |
1975年 | 1218篇 |
1974年 | 1341篇 |
1973年 | 1357篇 |
1972年 | 1369篇 |
1971年 | 1244篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
C Martín-García J Carnés R Blanco J C Martínez-Alonso A Callejo-Melgosa A Frades T Colino 《Journal of investigational allergology & clinical immunology》2007,17(4):271-273
Many types of seafood require cooking before ingestion and it has been demonstrated that this cooking process may affect the antigenicity and allergenicity of the food. We describe a case of anaphylaxis caused by selective sensitization to razor shell, a mollusc. In vivo and in vitro studies confirmed sensitization to boiled razor shell. Analysis of the nature of the allergen yielded results that were consistent with the findings of other authors and suggested that allergens involved in seafood allergy are commonly high molecular weight proteins that, in most cases, are heat stable. 相似文献
102.
103.
104.
105.
To produce hybrids, one member of the parental line is genetically made male-sterile. This male-sterile trait is encoded by mitochondria so that it is maternally inherited. Consequently, the progeny of a male-sterile plant is fully sterile. Nevertheless, during the handling of cytoplasmic male-sterile seed stocks, some mixture with seeds of the maintainer lines can occur. Up to the present time, the only way to check the homogeneity of the cytoplasmic male-sterile seed stock was to grow the plants until flowering time. We have developed a method which can be used immediately after the harvest, allowing us to check samples from both sunflower and sugar beet. We used the mitochondrial plasmid, present only in the maintainer lines, as a probe for the total nucleic acids prepared from the cytoplasmic male-sterile seed stocks which might be contaminated. The signals compared to those of samples artificially contaminated allow us to measure as few as one male-fertile seed in 1000 seeds in a rapid and accurate manner. 相似文献
106.
D Puluszézak A Bianchi J C Cazin M Cazin 《Methods and findings in experimental and clinical pharmacology》1991,13(6):419-425
A detailed examination of quantitative relationships of pharmacological action with plasma and tissue concentrations of indomethacin has been undertaken in the rat, after single oral administration of two sustained release preparations. In this study, drug was assayed by high performance liquid chromatography, whereas antiinflammatory response was assessed through the carrageenin-induced edema test. Significant linear correlations (p less than 0.001) were found between logarithmically transformed percent inhibition of edema and logarithmically transformed plasma, as well as tissue levels of indomethacin. However, the lack of significance for partial correlation regarding tissue concentration, contrary to plasma concentration, suggests that pharmacological response is more closely related to the latter, indicating that antidematous effect is mediated via the circulating drug rather than a local action in target tissues. This assumption is further discussed from the equivalence point of view. The relevance of this type of study in the case of topical administration of indomethacin is addressed as well. Taking into account the predictive value of the rat paw edema test for clinical efficacy, relationships similar to those observed are to be expected in man. The high correlation existing between plasma concentration of indomethacin and its pharmacological effect justifies the development and use of sustained release preparations in order to improve the outcome of treatment with this nonsteroidal antiinflammatory drug. 相似文献
107.
The distribution of tyrosine-hydroxylase (TH)-immunoreactive cell bodies and fibers in the diencephalon has been investigated with immunohistological techniques in the pigeon. The results suggest that TH is present in a number of morphologically distinct neuronal systems. Preoptic and hypothalamic TH neurons were subdivided into a medial periventricular and a lateral group. The medial group starts with a rostral collection of small cells in the preoptic region. A significantly larger collection of TH neurons occupies the paraventricular nucleus (PVN) (stratum cellulare internum) and mainly consists of large multipolar cells. Further caudally, the main concentration of cells is in the hypothalamic posteromedial and the periventricular regions of the tuberoinfundibular (arcuate) nucleus. No TH neuron was found in the ventral and lateral parts of the tuberoinfundibular region, suggesting that the prominent tuberoinfundibular dopaminergic system described in mammals is absent in the pigeon. This further substantiated by the relative scarcity of TH immunoreactive fibers and varicosities in the neurohemal zone of the median eminence (ME). The caudalmost components of the medial group appear to be continuous with the large population of TH neurons distributed in the midline of the mesencephalon. Tyrosine-hydroxylase-immunopositive cells have not been found in the paraventricular organ. The lateral group consists of TH neurons loosely arranged in the lateral hypothalamus, including regions of the supraoptic nucleus and hypothalamic posterolateral nucleus. Tyrosine-hydroxylase containing neurons vary widely in size, shape, and dendritic arborization in each diencephalic region. However, it is possible to distinguish two main cell types. Small bipolar neurons with two simple arborizing dendrites were concentrated in the medial periventricular system. The second type of cell is large, multipolar with four to five branching dendrites. This latter cell type occurs mainly in the lateral system and in the PVN. Major fiber bundles containing TH immunoreactivity were identified in the lateral and periventricular hypothalamus. The paraventricular organ and the organum vasculosum laminae terminalis contained the densest arborization of fibers and varicosities. In the ME, dense innervation was found in the subependymal layer. Dense arborizations of TH positive fibers and varicosities were located in the septal nuclei and the paleostriatum augmentatum. 相似文献
108.
Topographic electroencephalography was carried out to study reaction to photic stimulation in 29 normal volunteers, and 12 patients who had presented frequent clinically confirmed migraines for at least 3 years. In the group of migraineurs photic stimulation resulted in an increase in the alpha band power. The difference between the two groups was statistically significant. This reaction to photic stimulation is of help in diagnosis and suggests that a diagnosis and therapeutic orientation might be possible in patients for whom clinical diagnosis is not clear. The specificity of the migraineur's reaction to photic stimulation and its possible origin are discussed. 相似文献
109.
110.