全文获取类型
收费全文 | 956篇 |
免费 | 62篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 28篇 |
妇产科学 | 13篇 |
基础医学 | 78篇 |
口腔科学 | 47篇 |
临床医学 | 113篇 |
内科学 | 160篇 |
皮肤病学 | 20篇 |
神经病学 | 85篇 |
特种医学 | 115篇 |
外科学 | 102篇 |
综合类 | 36篇 |
预防医学 | 70篇 |
眼科学 | 62篇 |
药学 | 74篇 |
中国医学 | 1篇 |
肿瘤学 | 28篇 |
出版年
2020年 | 10篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 9篇 |
2016年 | 19篇 |
2015年 | 18篇 |
2014年 | 14篇 |
2013年 | 23篇 |
2012年 | 26篇 |
2011年 | 29篇 |
2010年 | 26篇 |
2009年 | 35篇 |
2008年 | 28篇 |
2007年 | 40篇 |
2006年 | 16篇 |
2005年 | 19篇 |
2004年 | 23篇 |
2003年 | 22篇 |
2002年 | 22篇 |
2001年 | 18篇 |
2000年 | 26篇 |
1999年 | 22篇 |
1998年 | 25篇 |
1997年 | 43篇 |
1996年 | 41篇 |
1995年 | 22篇 |
1994年 | 19篇 |
1993年 | 21篇 |
1992年 | 14篇 |
1991年 | 25篇 |
1990年 | 19篇 |
1989年 | 26篇 |
1988年 | 30篇 |
1987年 | 21篇 |
1986年 | 21篇 |
1985年 | 20篇 |
1984年 | 21篇 |
1983年 | 19篇 |
1982年 | 9篇 |
1981年 | 13篇 |
1980年 | 15篇 |
1979年 | 9篇 |
1978年 | 14篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1975年 | 10篇 |
1972年 | 9篇 |
1970年 | 10篇 |
1969年 | 9篇 |
1966年 | 11篇 |
排序方式: 共有1035条查询结果,搜索用时 0 毫秒
1.
2.
The role of growth factors and cytokines in the impaired healing of chronic leg ulcers remains uncertain. The aim of this study was to determine whether changes in the amount and location of cytokines and growth factors may be associated with impaired healing in chronic leg ulcers. Biopsies from leg ulcers of 21 patients and from normal skin of nine healthy volunteers were examined immunohistochemically for selected growth factors and cytokines. Greater staining intensity was found in keratinocytes at the edges of ulcers compared to normal skin, or skin adjacent to the ulcers. Staining at the ulcer edge was more intense in nonhealing ulcers for only vascular endothelial growth factor and platelet-derived growth factor, whereas staining in the adjacent skin was more intense for all factors in the nonhealing phase. For all factors staining was cytoplasmic, suggesting production in these areas. This study shows up-regulation of the production of cytokines and growth factors in keratinocytes of chronic leg ulcers that is greater when the ulcers are nonhealing. 相似文献
3.
4.
The event of preterm birth represents a significant risk to the equilibrium of the family, often placing the family under significant stress. This paper is intended to assist neonatal nurses in understanding factors related to a family's appraisal of stress and strategies used for coping. Such factors are an important consideration in planning the most effective interventions to support optimal family adaptation to their preterm infant's birth. In identifying the best clinical approaches to supporting a family coping with the event of a preterm birth, nurses need to consider levels of the evidence that supports adoption of clinical intervention strategies. Working to reduce family stress and improve family coping ensures the most optimal home environment for the preterm infant to grow and thrive in after discharge. 相似文献
5.
6.
Picotamide inhibition of excess in vitro thromboxane B2 release by colorectal mucosa in inflammatory bowel disease. 总被引:1,自引:0,他引:1
Collins CE Benson MJ Burnham WR Rampton DS 《Alimentary pharmacology & therapeutics》1996,10(3):315-320
BACKGROUND: Inflammatory bowel disease is associated with increased mucosal release of eicosanoids. Among these, thromboxane A2 has been proposed as a possible inflammatory mediator; its suppression may be a useful therapeutic option. METHODS: Using a tissue incubation technique, we compared release of immunoreactive thromboxane B2 by colonic biopsies from patients with ulcerative colitis, Crohn's disease and controls, and assessed the inhibitory effect of picotamide, a thromboxane synthesis inhibitor-receptor antagonist, which has been widely used in Italy for management of ischaemic heart and cerebrovascular disease. RESULTS: Increased amounts of thromboxane B2 were released from biopsies from patients with active ulcerative colitis (median 238 pg/20 min/mg wet weight (interquartile range 147- 325), n = 12) and active Crohn's disease (252 (174-450), 6) compared with those from patients with quiescent ulcerative colitis (95 (61- 140), 12) or Crohn's disease (105 (57-201), 13), or controls (136 (64- 206), 8). Incubation with picotamide at concentrations between 100 microM and 1 mM reduced thromboxane B2 release (IC50 890 microM). CONCLUSION: Since increased thromboxane A2 production may have pathogenetic importance, thromboxane synthesis inhibitor-receptor antagonists such as picotamide merit therapeutic trial in the management of inflammatory bowel disease. 相似文献
7.
Anderson RA; Evans LW; Irvine DS; McIntyre MA; Groome NP; Riley SC 《Human reproduction (Oxford, England)》1998,13(12):3319-3325
Follistatin is a binding protein for the activin and inhibin family of
hormones, regulating their biological activity. In the male reproductive
tract, the interaction of these factors is likely to be involved in the
regulation of the proliferation of several cell types. We have investigated
the presence of follistatin and activin A in seminal plasma using specific
immunoassays and have localized follistatin and activin/inhibin subunits in
the adult human testis, prostate and seminal vesicle to establish their
likely sources. High concentrations of immunoreactive follistatin were
present in seminal plasma in normal men (mean 97.9 ng/ml; 1.43 ng/ml in
peripheral plasma) and were similar in men with oligo/azoospermia and
following vasectomy. Follistatin immunoreactivity was localized to both
Leydig and Sertoli cells of the testis, and to epithelial cells of the
prostate gland and seminal vesicle, which are likely to be the predominant
sources of the hormone in seminal plasma. Activin A was also present in
seminal plasma in normal men but was undetectable following vasectomy, thus
deriving from the testis. Consistent with this finding, the betaA-subunit
was immunolocalized in Sertoli and Leydig cells but was not present in
seminal vesicle or prostate gland. The functional significance of the high
concentrations of follistatin secreted into seminal plasma by the prostate
gland and/or seminal vesicle is uncertain, but they may regulate the
biological activity of testis-derived activin A and inhibin B.
相似文献
8.
Alcohol as a risk factor for injury or death resulting from accidental falls: a review of the literature 总被引:8,自引:0,他引:8
An examination of the English language literature published from 1950 to 1985 on the subject of alcohol consumption and falls yielded 21 studies. Those identified represented four types. Type I studies examined alcohol exposure among fall cases. The percentage of fatal falls related to alcohol exposure ranged from 21 to 77%; for nonfatal falls the range was 17-53%. Among Type II studies comparing fatal falls among alcoholics to the standard population, ratios of observed to expected deaths ranged from 2.9 to 16. Type III studies compared blood alcohol levels (BALs) of fall patients and disease patients treated medically. Those studies yielded odds ratios from 2.5 to 10. In the single Type IV study comparing BALs of fall subjects with nonfall controls relative risks were 1 (BALs, 50-100 mg/dl), 3 (BALs, 100-150 mg/dl) and 60 (BALs, greater than 160 mg/dl). We conclude that there is substantial evidence that alcohol increases risks for falls, but that more case-control studies (Type IV) are required to evaluate the exact magnitude of this risk and intervention studies are needed to assess methods to reduce the risk. 相似文献
9.
10.
Identification of two mutations in a compound heterozygous child with dihydrolipoamide dehydrogenase deficiency 总被引:1,自引:0,他引:1
Hong YS; Kerr DS; Craigen WJ; Tan J; Pan Y; Lusk M; Patel MS 《Human molecular genetics》1996,5(12):1925-1930
An infant girl with elevated blood lactate, pyruvate, and plasma
branched-chain amino acids was diagnosed with dihydrolipoamide
dehydrogenase (E3; dihydrolipoamide: NAD+ oxidoreductase, EC 1.8.1.4)
deficiency. Activities of the pyruvate dehydrogenase complex and E3 from
patient were 26 and 2% of controls in blood lymphocytes, and 11 and 14% in
cultured skin fibroblasts, respectively. Western blot analysis demonstrated
that the amount of E3 protein in fibroblasts from the patient and her
father was about half of controls, while Northern blot analysis showed
normal amounts of E3 RNA. DNA sequencing of cloned full-length E3 cDNAs
from the patient revealed two mutations in separate alleles. One is a
single base insertion of an extra adenine in the last codon of the leader
peptide sequence (TAC-->TAAC) leading to a nonsense mutation which
results in the premature termination of the precursor E3 polypeptide
(Y35X). The other is a missense mutation due to substitution of guanine for
adenine, causing an Arg-->Gly substitution at amino acid 460 of the
mature protein (R460G) which triggers the loss of E3 activity probably by
structural change in the E3 dimer. DNA sequencing of E3 cDNAs from the
parents demonstrated that the nonsense mutation was inherited from the
father and the missense mutation was inherited from the mother.
相似文献