全文获取类型
收费全文 | 2044802篇 |
免费 | 152550篇 |
国内免费 | 3131篇 |
专业分类
耳鼻咽喉 | 29574篇 |
儿科学 | 64089篇 |
妇产科学 | 54269篇 |
基础医学 | 290171篇 |
口腔科学 | 58142篇 |
临床医学 | 178102篇 |
内科学 | 405740篇 |
皮肤病学 | 43848篇 |
神经病学 | 159673篇 |
特种医学 | 81253篇 |
外国民族医学 | 725篇 |
外科学 | 322921篇 |
综合类 | 42086篇 |
现状与发展 | 2篇 |
一般理论 | 577篇 |
预防医学 | 147021篇 |
眼科学 | 46019篇 |
药学 | 155146篇 |
5篇 | |
中国医学 | 4206篇 |
肿瘤学 | 116914篇 |
出版年
2018年 | 20161篇 |
2017年 | 15482篇 |
2016年 | 17114篇 |
2015年 | 19352篇 |
2014年 | 26762篇 |
2013年 | 40299篇 |
2012年 | 55154篇 |
2011年 | 58116篇 |
2010年 | 34727篇 |
2009年 | 33200篇 |
2008年 | 56256篇 |
2007年 | 59877篇 |
2006年 | 60723篇 |
2005年 | 58851篇 |
2004年 | 57397篇 |
2003年 | 55486篇 |
2002年 | 54497篇 |
2001年 | 107560篇 |
2000年 | 111634篇 |
1999年 | 94254篇 |
1998年 | 23898篇 |
1997年 | 21356篇 |
1996年 | 21801篇 |
1995年 | 20512篇 |
1994年 | 19228篇 |
1993年 | 17776篇 |
1992年 | 73353篇 |
1991年 | 71177篇 |
1990年 | 69088篇 |
1989年 | 66562篇 |
1988年 | 61042篇 |
1987年 | 59785篇 |
1986年 | 55743篇 |
1985年 | 53504篇 |
1984年 | 39192篇 |
1983年 | 33058篇 |
1982年 | 18267篇 |
1981年 | 16339篇 |
1979年 | 34922篇 |
1978年 | 23840篇 |
1977年 | 20415篇 |
1976年 | 18419篇 |
1975年 | 20120篇 |
1974年 | 23825篇 |
1973年 | 22735篇 |
1972年 | 21221篇 |
1971年 | 19683篇 |
1970年 | 18642篇 |
1969年 | 17171篇 |
1968年 | 15563篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
941.
Spectral analysis of the electroencephalogram in neonatal rats chronically treated with the NMDA antagonist MK-801. 总被引:1,自引:0,他引:1
J A Gorter M Veerman M Mirmiran N P Bos M A Corner 《Brain research. Developmental brain research》1991,64(1-2):37-41
In order to study the involvement of NMDA-receptor activation in brain development, rat pups were chronically treated with the non-competitive NMDA antagonist MK-801 during the neonatal period. We recorded the cortical EEG at various vigilance states throughout the treatment period. Spectral analysis of the EEG showed reduced power in the delta (delta) frequency range (1.5-4 Hz) during quiet sleep and less power in the theta (theta) range (4-7 Hz) during REM-sleep in MK-801 animals than in controls. No significant differences were found for the total time spent in each of the different vigilance states. We conclude that chronic MK-801 treatment probably causes a developmental retardation in state-related brain activities. 相似文献
942.
Transneuronal degeneration of thalamic neurons following partial deafferentation was studied using [3H]thymidine autoradiography. Timed-pregnant female Sprague-Dawley rats received systemic injections of [3H]thymidine on embryonic day (E) 13, 14 and/or 15. On the day of birth, pups were anesthetized by hypothermia and subjected to unilateral enucleation, unilateral removal of the inferior colliculus or sham lesion. Animals were sacrificed on postnatal day 10 or 30 and the brains processed for autoradiography. Material from sham-lesioned animals demonstrates that neurons destined for the dorsal lateral geniculate nucleus (LGd) undergo final mitoses on E13, 14 and 15. Neurons in the ventral medial geniculate nucleus (MGv) undergo final mitoses on E13 and 14. Thirty days following neonatal unilateral eye removal, the contralateral LGd displays a loss of approximately 30-35% of [3H]thymidine labeled neurons. Neonatal unilateral removal of the inferior colliculus results in a loss of approximately 30-40% of labeled neurons in MGv. For both LGd and MGv, shorter survival times reveal less severe cell loss. Late generated (E15) LGd neurons show less severe loss following enucleation than do earlier generated neurons. These results document the degree of cell loss in sensory thalamic nuclei following deafferentation and demonstrate that [3H]thymidine autoradiography provides a useful quantitative method for assessing anterograde transneuronal cell loss in targeted populations of neurons in the developing central nervous system. 相似文献
943.
We developed a novel method which enables bloodless exposure of the levator veli palatini muscle in rat in order to investigate the physiological properties of this muscle. The levator veli palatini muscle which is innervated by a branch of the glossopharyngeal nerve showed rhythmic spontaneous movement in rats. Cutting the branch supplying LVP of the glossopharyngeal nerve caused cessation of the spontaneous movement of the levator veli palatini muscle. The spontaneous discharges of the glossopharyngeal nerve were synchronized with those of the phrenic nerve. A mixture of 95% oxygen and 5% room air influenced the efferent discharges from the branch of the glossopharyngeal nerve supplying the levator veli palatini muscle. These findings indicate that the motor nerve supply to the levator veli palatini muscle is the glossopharyngeal nerve, and the levator veli palatini muscle is related to the respiratory system, in particular with inspiration in rats. 相似文献
944.
945.
A total of 102 patients were examined, 32 of these with true eczema, 38 with exudative mycosis of the soles, and 32 with eczema etiologically related to a fungal infection. Analysis of the immune and biochemical reactions in the examinees has shown a marked reduction of adenyl nucleotides in the leukocytic suspension and neutrophils of patients with a mycotic infection as against those with true eczema. The lowest creatine phosphate levels were detected in the leukocytic suspension and neutrophils of the patients suffering from eczema etiologically related to mycosis and exudative mycosis of the soles. These results give grounds to search for effective corrective therapy. 相似文献
946.
947.
P G Crosignani A M Mattei C Scarduelli V Cavioni P Boracchi 《Human reproduction (Oxford, England)》1989,4(8):910-912
This paper reports the changes in prolactin levels after 12 spontaneous and 52 induced pregnancies in 54 women with unambiguous hyperprolactinaemia (median plasma prolactin levels 67.5 ng/ml, range 40-400). Twenty-three of the patients showed radiological evidence of prolactinoma. The pregnancies were induced in 37 patients by bromocriptine, in nine by metergoline, in two by lisuride and in four by other treatments. Of the 64 pregnancies, 16 ended in spontaneous abortion, while 48 went to term. Follow-up was continued for at least 6 months after delivery or until the end of lactation. In a control group of 32 hyperprolactinaemic women (median prolactin 70 ng/ml, range 40-400) not wishing to become pregnant, prolactin changes were similarly registered over a mean period of 15 months without any treatment (range 6-38 months). After pregnancy, a significant downward trend of plasma prolactin was observed in the puerperal women with a 'normalization' rate of 17%. No changes were observed in the 32 controls who did not become pregnant. 相似文献
948.
949.
950.
J M Debets R Kampmeijer M P van der Linden W A Buurman C J van der Linden 《Critical care medicine》1989,17(6):489-494
Tumor necrosis factor (TNF) cachectin has been implicated as an important host mediator responsible for shock and multiple organ failure (MOF) observed during sepsis. Using a sensitive enzyme-linked immunosorbent assay, we measured plasma TNF levels in 43 septic patients suffering from a broad range of diseases. Measurements were taken on the day that sepsis was diagnosed. Eleven patients had detectable TNF plasma levels ranging from 10 to 100 pg/ml (TNF-positive group); in 32 patients circulating TNF could not be detected (TNF-negative group). The groups did not differ significantly as to age, underlying disease, percentage positive bacteremia and bacteriologic profile, sepsis score, and extent of MOF. Eight (73%) of 11 TNF-positive patients died from sepsis during ICU stay, vs. 11 (34%) of 32 TNF-negative patients (p less than .05). This study demonstrates that sepsis is accompanied by detectable circulating TNF in 25% of the cases, and for these patients mortality is twice that for comparable TNF-negative patients. 相似文献