全文获取类型
收费全文 | 3125篇 |
免费 | 254篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 57篇 |
儿科学 | 265篇 |
妇产科学 | 97篇 |
基础医学 | 499篇 |
口腔科学 | 50篇 |
临床医学 | 306篇 |
内科学 | 751篇 |
皮肤病学 | 25篇 |
神经病学 | 284篇 |
特种医学 | 153篇 |
外国民族医学 | 1篇 |
外科学 | 352篇 |
综合类 | 73篇 |
一般理论 | 2篇 |
预防医学 | 147篇 |
眼科学 | 101篇 |
药学 | 118篇 |
中国医学 | 2篇 |
肿瘤学 | 112篇 |
出版年
2021年 | 27篇 |
2019年 | 34篇 |
2018年 | 45篇 |
2017年 | 30篇 |
2016年 | 37篇 |
2015年 | 44篇 |
2014年 | 58篇 |
2013年 | 86篇 |
2012年 | 122篇 |
2011年 | 126篇 |
2010年 | 105篇 |
2009年 | 68篇 |
2008年 | 96篇 |
2007年 | 110篇 |
2006年 | 102篇 |
2005年 | 95篇 |
2004年 | 107篇 |
2003年 | 100篇 |
2002年 | 77篇 |
2001年 | 93篇 |
2000年 | 112篇 |
1999年 | 97篇 |
1998年 | 59篇 |
1997年 | 61篇 |
1996年 | 57篇 |
1995年 | 52篇 |
1994年 | 43篇 |
1993年 | 39篇 |
1992年 | 85篇 |
1991年 | 88篇 |
1990年 | 57篇 |
1989年 | 72篇 |
1988年 | 74篇 |
1987年 | 76篇 |
1986年 | 74篇 |
1985年 | 62篇 |
1984年 | 40篇 |
1983年 | 45篇 |
1982年 | 27篇 |
1981年 | 38篇 |
1980年 | 25篇 |
1979年 | 39篇 |
1978年 | 27篇 |
1977年 | 38篇 |
1976年 | 24篇 |
1974年 | 24篇 |
1971年 | 22篇 |
1926年 | 23篇 |
1925年 | 28篇 |
1924年 | 22篇 |
排序方式: 共有3395条查询结果,搜索用时 15 毫秒
31.
32.
Calcitonin gene-related peptide in cardiovascular tissues of the rat 总被引:15,自引:0,他引:15
P K Mulderry M A Ghatei J Rodrigo J M Allen M G Rosenfeld J M Polak S R Bloom 《Neuroscience》1985,14(3):947-954
The distribution of calcitonin gene-related peptide immunoreactivity in the cardiovascular system of the rat was investigated by radioimmunoassay and immunocytochemistry. The nature of the immunoreactivity was studied by gel permeation and high performance liquid chromatography. Immunocytochemistry demonstrated the existence of calcitonin gene-related peptide-containing nerve fibres throughout the cardiovascular system. These were present in all regions of the heart, particularly in association with the coronary arteries, within the papillary muscles and within the sinoatrial and atrioventricular nodes. Calcitonin gene-related peptide-containing fibres were found mainly in the adventitia of the arteries and veins. Calcitonin gene-related peptide concentrations were high in major arteries and veins but comparatively low in the heart, aortic arch and thoracic aorta. Chromatography showed that approximately 70% of the total immunoreactivity was identical to synthetic calcitonin gene-related peptide. Calcitonin gene-related peptide concentrations in the blood vessels of rats treated neonatally with capsaicin were not found to be significantly different from those in control animals although capsaicin caused significant reductions of calcitonin gene-related peptide levels in certain other tissues. The results of this study suggest that calcitonin gene-related peptide-containing fibres are likely to be of importance in the innervation of vascular tissues and raise the possibility that these fibres are different in character from calcitonin gene-related peptide-containing fibres found in other tissues. 相似文献
33.
34.
Effect of Chlamydia pneumoniae on cellular ATP content in mouse macrophages: role of Toll-like receptor 2
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yaraei K Campbell LA Zhu X Liles WC Kuo CC Rosenfeld ME 《Infection and immunity》2005,73(7):4323-4326
Chlamydiae are obligate intracellular gram-negative bacteria and are dependent on the host cell for ATP. Thus, chlamydial infection may alter the intracellular levels of ATP and affect all energy-dependent processes within the cell. We have shown that both live C. pneumoniae and inactivated C. pneumoniae induce markers of cell death prior to completion of the bacterial growth cycle. As depletion of ATP could account for the observed increase in cell death, the effects of C. pneumoniae on ATP concentrations within mouse macrophages were investigated. Live, heat-killed, and UV-inactivated C. pneumoniae cultures (at multiplicities of infection [MOIs] of 0.01, 0.1, and 1.0) were incubated with mouse bone marrow macrophages isolated from C57BL/6J mice and mice deficient in Toll-like receptors. Treatment of the macrophages with both live and inactivated C. pneumoniae increased the ATP content of the cells. In cells infected with live C. pneumoniae, the increase was inversely proportional to the MOI. In cells treated with inactivated C. pneumoniae, the increase in ATP content was smaller than that induced by infection with live organisms and was proportional to the MOI. The increase in ATP content early in the developmental cycle was independent of the growth of C. pneumoniae, while sustained induction required live organisms. The capacity of C. pneumoniae to increase the ATP content was ablated in macrophages deficient in expression of either Toll-like receptor 2 or the Toll-like receptor accessory protein MyD88. In contrast, no effect was observed in macrophages lacking expression of Toll-like receptor 4. 相似文献
35.
L O Maddox M Descartes J Collins J Keating S Rosenfeld C Palmer A J Carroll R Kuzniecky 《Journal of medical genetics》1997,34(7):590-591
Patients affected with progressive myoclonus epilepsy of the Lafora type present during late adolescence with a characteristic EEG pattern and Lafora bodies seen on skin biopsy. The critical region for the Lafora gene has been localised to chromosome 6q24 flanked by the dinucleotide repeat markers D6S292 and D6S420. This study for linkage of markers from the candidate gene region was performed in a previously unpublished family affected with Lafora disease. EEG and skin biopsy evaluation for Lafora bodies were performed on five of eight family members followed for seizure activity. Haplotype and linkage analysis of DNA from five family members were carried out using the nine dinucleotide repeat markers reported in the common region of homozygosity by Serratosa et al in 1995. The present study of an additional family affected by Lafora disease has narrowed the 17 cM critical region for the Lafora disease gene on chromosome 6q24 to a 4 cM region flanked by markers D6S308 and D6S311. 相似文献
36.
Ghazzawi IM; Sarraf MG; Taher MR; Khalifa FA 《Human reproduction (Oxford, England)》1998,13(2):348-352
A prospective study was carried out to compare the fertilizing capability
and pregnancy outcome following intracytoplasmic sperm injection (ICSI)
using spermatozoa obtained from ejaculates, or surgically from epididymis
or seminiferous tubules. A total of 77 ICSI cycles (one per patient) was
included. In all, 28 patients had severe oligoasthenoteratozoospermia, 19
patients had obstructive azoospermia and 30 patients had non-obstructive
azoospermia. The main outcome measures were fertilization rate per injected
metaphase II oocyte and the clinical pregnancy rate per embryo transferred
back to the female recipients. In patients with severe
oligoasthenoteratozoospermia, the fertilization and pregnancy rates were 79
and 25 %. In patients with obstructive azoospermia, for whom epididymal
spermatozoa were used, these were 75 and 28%, and in the non-obstructive
group for which testicular spermatozoa were used for injection, they were
69 and 21% respectively. These rates were not significantly different in
the three groups (P = 0.85 and P = 0.14 respectively), suggesting that
spermatozoa from the ejaculates and epididymal or testicular biopsies are
able to fertilize equally by using ICSI. Live birth per embryo transfer was
significantly reduced in patients with non-obstructive azoospermia compared
to the other two groups. The high abortion rate (50%) in the group in which
testicular spermatozoa were used raises doubts about the developmental
competence of such embryos.
相似文献
37.
38.
Berge-Lefranc JL; Jay P; Massacrier A; Cau P; Mattei MG; Bauer S; Marsollier C; Berta P; Fontes M 《Human molecular genetics》1996,5(10):1637-1641
While constructing a cDNA library of human embryos, we have isolated a
clone homologous to jumonji, a mouse gene required for neural tube
formation. We have determined the complete coding sequence of the human
homologue (JMJ) and deduced the amino acid sequence of the putative
protein. We show here that human and mouse jumonji putative proteins are
homologous and present 90% identity. During human embryogenesis, JMJ mRNAs
are predominantly expressed in neurons and particularly in dorsal root
ganglion cells. They are also expressed in neurons of human adult cerebral
cortex. In view of these observations, we propose JMJ as a candidate gene
for developmental defects of the central nervous system in the human. The
human JMJ gene maps at position 6p24-6p23.
相似文献
39.
Previous data indicate that the infant rat shows a marked increase in adrenocortical responsiveness to stress immediately following prolonged maternal separation. In Experiment 1 we studied the immediate effects of repeated maternal deprivation. Our results indicate that the increase in basal as well as stress-induced corticosterone levels is a direct function of the length of the deprivation period immediately preceding testing, and is not cumulative. In Experiment 2 we examined the long-term consequences of maternal deprivation on adrenal responsivity. Four days following a single 24-h period of maternal deprivation, pups remained hyperresponsive to stress, although their basal levels of corticosterone had returned to control values. Shorter periods of deprivation (which did result in increased responsivity immediately following deprivation) did not have persistent effects. Our data suggest: 1) short periods of deprivation do not have a cumulative effect, and 2) there is a critical length of deprivation beyond which persistent changes in adrenocortical responsivity ensue. 相似文献
40.