全文获取类型
收费全文 | 7003篇 |
免费 | 595篇 |
国内免费 | 501篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 49篇 |
妇产科学 | 67篇 |
基础医学 | 1495篇 |
口腔科学 | 42篇 |
临床医学 | 326篇 |
内科学 | 1333篇 |
皮肤病学 | 46篇 |
神经病学 | 305篇 |
特种医学 | 103篇 |
外科学 | 669篇 |
综合类 | 1492篇 |
现状与发展 | 3篇 |
预防医学 | 97篇 |
眼科学 | 49篇 |
药学 | 1550篇 |
中国医学 | 428篇 |
肿瘤学 | 38篇 |
出版年
2023年 | 46篇 |
2022年 | 55篇 |
2021年 | 101篇 |
2020年 | 107篇 |
2019年 | 112篇 |
2018年 | 120篇 |
2017年 | 138篇 |
2016年 | 136篇 |
2015年 | 168篇 |
2014年 | 263篇 |
2013年 | 345篇 |
2012年 | 383篇 |
2011年 | 434篇 |
2010年 | 372篇 |
2009年 | 426篇 |
2008年 | 394篇 |
2007年 | 404篇 |
2006年 | 394篇 |
2005年 | 370篇 |
2004年 | 361篇 |
2003年 | 365篇 |
2002年 | 314篇 |
2001年 | 233篇 |
2000年 | 249篇 |
1999年 | 190篇 |
1998年 | 226篇 |
1997年 | 203篇 |
1996年 | 145篇 |
1995年 | 133篇 |
1994年 | 105篇 |
1993年 | 98篇 |
1992年 | 89篇 |
1991年 | 78篇 |
1990年 | 60篇 |
1989年 | 60篇 |
1988年 | 46篇 |
1987年 | 46篇 |
1986年 | 29篇 |
1985年 | 34篇 |
1984年 | 30篇 |
1983年 | 28篇 |
1982年 | 34篇 |
1981年 | 44篇 |
1980年 | 17篇 |
1979年 | 26篇 |
1978年 | 27篇 |
1977年 | 21篇 |
1976年 | 12篇 |
1974年 | 7篇 |
1973年 | 9篇 |
排序方式: 共有8099条查询结果,搜索用时 31 毫秒
1.
Chrystalle Katte Carreon Annachiara Benini Christopher Baird David Hoganson Michele Borisuk Sitaram Emani Sophie Hofferberth Robert F. Padera Stephen P. Sanders 《The Journal of thoracic and cardiovascular surgery》2019,157(1):342-350.e3
Objectives
Although valved venous homografts (VVHs) are used for establishing right ventricle-to-pulmonary artery continuity in some complex heart defects, the tissue changes that occur in situ have not been described. We review the gross and microscopic changes observed in explanted VVH conduits and their effects on functionality.Methods
In total, 20 explanted VVH conduits were evaluated for valve integrity, presence of thrombus, and stenosis. Hematoxylin and eosin– and trichrome-stained sections were reviewed for neointima formation, wall remodeling, inflammation, and calcification. Regurgitation and narrowing were assessed on pre-explant echocardiogram, and angiographic video clips were correlated with tissue findings. The source of the proliferating cells within the conduits was investigated by fluorescent in situ hybridization.Results
Thirteen male and 7 female infants underwent VVH implantation either as part of a composite Sano shunt (65%) or to establish right ventricle-to-pulmonary artery continuity in biventricular hearts (35%). The median duration of conduits in situ was 140 days (range: 98-340 days). Conduits were predominantly explanted for staged conversion to bidirectional Glenn (60%) and conduit upsizing (20%). The valves remained intact and functional in 75% of cases. Occlusive thrombosis was absent in all. Wall thickening due to neointima formation and wall remodeling was uniformly present and appeared to be driven by smooth muscle actin–expressing cells, which by fluorescent in situ hybridization are predominantly of recipient origin. Minimal calcification and mild adventitial chronic inflammation were present.Conclusions
Vein wall thickening is a uniform finding and can cause stenosis. The valves remain functional in most, and vein walls undergo remodeling with only minimal inflammation and calcification. 相似文献2.
3.
Notch1 has been implicated in asthma pathogenesis. However, the function of Notch1 in regulating airway smooth muscle (ASM) cell proliferation and migration during airway remodeling of asthma remains unknown. Using an in vitro model induced by tumor necrosis factor (TNF)-α, we reported in this study that Notch1 participated in TNF-α-induced proliferation and migration of ASM cells. Our results demonstrated that Notch1 expression was significantly upregulated in ASM cells exposed to TNF-α. Notch1 inhibition significantly repressed TNF-α-induced ASM cell proliferation and migration, while Notch1 overexpression promoted the opposite effect. Moreover, Notch1 inhibition downregulated the expression of Notch-1 intracellular domain (NICD) and Hes1, while upregulated PTEN expression in TNF-α-exposed cells. Notably, Hes1 overexpression partially reversed the Notch1-inhibition-mediated inhibitory effect on TNF-α-induced ASM cell proliferation and migration. In addition, the promoting effect of Notch1 inhibition on PTEN expression was markedly abrogated by Hes1 overexpression. Overall, these findings demonstrated that Notch1 inhibition repressed TNF-α-induced ASM cell proliferation and migration by modulating the Hes1/PTEN signaling axis, a finding that highlights the involvement of Notch1/Hes1/PTEN in regulating airway remodeling of asthma. 相似文献
4.
Phoebe Hammer Kevin White Stephanie Mengden Vessy Korcheva Philipp W. Raess 《Journal of cutaneous pathology》2019,46(5):343-346
Cutaneous leiomyomas are rare benign smooth‐muscle tumors. These lesions are distinguished based on their cell of origin and are subclassified as pilar leiomyoma, angioleiomyoma, and genital‐type leiomyoma. Nipple leiomyoma is the least common genital‐type leiomyoma, arising from the dartoic muscle cell of the nipple. Histologic examination of the lesion is necessary for definitive diagnosis, and these uncommon tumors can pose a diagnostic challenge. We describe herein a series of six nipple leiomyomas with a spectrum of histologic appearances. 相似文献
5.
Atherosclerosis has long been known as an inflammatory disease. However, whether targeting inflammation improves outcomes was unproven until the recent results of CANTOS (Canakinumab Anti-Inflammatory Thrombosis Outcomes Study). In this review, we reflect on why it has taken a long time to prove the inflammatory hypothesis of atherosclerosis and derive important lessons for the future. In particular, we discuss the off-target immune-modulatory effects of approved cardiovascular therapies, review the attempted anti-inflammatory therapies including the recently published CIRT (Cardiovascular Inflammation Reduction Trial), and discuss the likely reasons for their failures. We further build on CANTOS to review the immune-modulatory therapies for atherosclerosis currently in trials, and discuss the likelihood of their added value as well as the potential hazard associated with their use. We finally argue for a critical approach to the use of animal models, coupled with the use of humans as model organisms to accelerate the identification of the most appropriate targets. 相似文献
6.
Aging alters bladder functions where a decrease in filling, storage and emptying is observed. These changes cause urinary incontinence, especially in women. The aim of this study is to examine how aging affects the intracellular calcium movements due to agonist-induced contractions in permeabilized female rat bladder. Urinary bladder isolated from young and old female Sprague-Dawley rats were used. Small detrusor strips were permeabilized with β-escin. The contractile responses induced with agonists were compared between young and old groups. Carbachol-induced contractions were decreased in permeabilized detrusor from old rats compared to young group. Heparin and ryanodine decreased carbachol-induced contractions in young rats where only heparin inhibited these contractions in olds. Caffeine-induced contractions but not inositol triphosphate (IP3)-induced contractions were decreased in old group compared to youngs. The cumulative calcium response curves (pCa 8–4) were also decreased in old rats. Carbachol-induced calcium sensitization responses did not alter by age where GTP-β-S and GF-109203X but not Y-27632 inhibited these responses. Carbachol-induced contractions decrease with aging in rat bladder detrusor. It can be postulated as IP3-induced calcium release (IICR) is primarily responsible for the contractions in older rats where the decrease in carbachol contractions in aging may be as a result of a decrease in calcium-induced calcium release (CICR), rather than carbachol-induced calcium sensitization. 相似文献
7.
8.
Zehua Li Ji Wu Xiuli Zhang Caiwen Ou Xinglong Zhong Yanting Chen Lihe Lu Hailin Liu Yining Li Xiaoyu Liu Bo Wu Yuxi Wang Pingzhen Yang Jianyun Yan Minsheng Chen 《The Journal of pathology》2019,249(4):461-471
Vascular calcification is prevalent in patients with chronic kidney disease (CKD) and a major risk factor of cardiovascular disease. Vascular calcification is now recognised as a biological process similar to bone formation involving osteogenic differentiation of vascular smooth muscle cells (VSMCs). Cell division cycle 42 (CDC42), a Rac1 family member GTPase, is essential for cartilage development during endochondral bone formation. However, whether CDC42 affects osteogenic differentiation of VSMCs and vascular calcification remains unknown. In the present study, we observed a significant increase in the expression of CDC42 both in rat VSMCs and in calcified arteries during vascular calcification. Alizarin red staining and calcium content assay revealed that adenovirus-mediated CDC42 overexpression led to an apparent VSMC calcification in the presence of calcifying medium, accompanied with up-regulation of bone-related molecules including RUNX2 and BMP2. By contrast, inhibition of CDC42 by ML141 significantly blocked calcification of VSMCs in vitro and aortic rings ex vivo. Moreover, ML141 markedly attenuated vascular calcification in rats with CKD. Furthermore, pharmacological inhibition of AKT signal was shown to block CDC42-induced VSMC calcification. These findings demonstrate for the first time that CDC42 contributes to vascular calcification through a mechanism involving AKT signalling; this uncovered a new function of CDC42 in regulating vascular calcification. This may provide a potential therapeutic target for the treatment of vascular calcification in the context of CKD. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. 相似文献
9.
Payal Chauhan MD DNB Nancy Bhardwaj MD Rashmi Jindal MD Nadia Shirazi MD 《Pediatric dermatology》2020,37(1):251-253
Cutaneous smooth muscle hamartoma is an uncommon, benign tumor developing in the dermis as a result of disorganized hyperproliferation of arrector pili muscle fibers. We present a 1-month-old infant with a congenital smooth muscle hamartoma together with the dermoscopic findings of the case. Dermoscopy can be a helpful non-invasive tool in diagnosing congenital smooth muscle hamartoma due to its distinct findings that help to differentiate it from close mimickers like solitary mastocytoma. 相似文献
10.
Perfluorooctanesulfonate (PFOS) is a persistent environmental agent. We examined whether PFOS exposure during pregnancy alters blood pressure in male and female offspring, and if this is related to sex-specific changes in vascular mechanisms. PFOS was administered through drinking water (50 μg/mL) to pregnant Sprague-Dawley rats from gestational day 4 until delivery. PFOS-exposure decreased maternal weight gain but did not significantly alter feed and water intake in dams. The male and female pups born to PFOS mothers were smaller in weight by 29 % and 27 %, respectively. The male PFOS offspring remained smaller through adulthood, but the female PFOS offspring exhibited catch-up growth. The blood pressure at 12 and 16 weeks of age was elevated at similar magnitude in PFOS males and females than controls. Mesenteric arterial relaxation to acetylcholine was reduced in both PFOS males and females, but the extent of decrease was greater in females. Relaxation to sodium-nitroprusside was reduced in PFOS females but unaffected in PFOS males. Vascular eNOS expression was not changed, but phospho(Ser1177)-eNOS was decreased in PFOS males. In PFOS females, both total eNOS and phospho(Ser1177)-eNOS expression were reduced. In conclusion, PFOS exposure during prenatal life (1) caused low birth weight followed by catch-up growth only in females (2) lead to hypertension of similar magnitude in both males and females; (2) decreased endothelium-dependent vascular relaxation in males but suppressed both endothelium-dependent and -independent relaxation in females. The endothelial dysfunction is associated with reduced activity of eNOS in males and decreased expression and activity of eNOS in females. 相似文献