全文获取类型
收费全文 | 2352篇 |
免费 | 279篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 71篇 |
妇产科学 | 88篇 |
基础医学 | 231篇 |
口腔科学 | 25篇 |
临床医学 | 315篇 |
内科学 | 444篇 |
皮肤病学 | 22篇 |
神经病学 | 320篇 |
特种医学 | 62篇 |
外科学 | 346篇 |
综合类 | 49篇 |
一般理论 | 1篇 |
预防医学 | 142篇 |
眼科学 | 134篇 |
药学 | 226篇 |
中国医学 | 5篇 |
肿瘤学 | 149篇 |
出版年
2023年 | 39篇 |
2022年 | 32篇 |
2021年 | 88篇 |
2020年 | 54篇 |
2019年 | 59篇 |
2018年 | 97篇 |
2017年 | 83篇 |
2016年 | 83篇 |
2015年 | 89篇 |
2014年 | 111篇 |
2013年 | 123篇 |
2012年 | 185篇 |
2011年 | 194篇 |
2010年 | 93篇 |
2009年 | 111篇 |
2008年 | 123篇 |
2007年 | 161篇 |
2006年 | 139篇 |
2005年 | 83篇 |
2004年 | 71篇 |
2003年 | 70篇 |
2002年 | 61篇 |
2001年 | 58篇 |
2000年 | 50篇 |
1999年 | 38篇 |
1998年 | 28篇 |
1997年 | 27篇 |
1996年 | 20篇 |
1995年 | 11篇 |
1994年 | 9篇 |
1993年 | 10篇 |
1992年 | 27篇 |
1991年 | 17篇 |
1990年 | 13篇 |
1989年 | 17篇 |
1988年 | 14篇 |
1987年 | 22篇 |
1986年 | 17篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1971年 | 9篇 |
1969年 | 6篇 |
1966年 | 5篇 |
排序方式: 共有2638条查询结果,搜索用时 46 毫秒
61.
62.
63.
64.
We have identified and molecularly characterized a novel deletion in the beta-globin gene cluster that increases fetal hemoglobin (HbF) synthesis in a 24-year-old Laotian man who is heterozygous for this mutation. The patient is asymptomatic with a mild anemia, hypochromia, and microcytosis (Ht = 39%, MCH = 22.8 pg, MCV = 71 fl), normal levels of HbA2 (3.0%) and 11.5% HbF (G gamma A gamma ratio 60 to 40), with heterocellular distribution (52% F cells). Extensive restriction endonuclease mapping defined the 5' breakpoint within the IVS II of the delta-globin gene, between positions 775 to 781 very similar to the 5' breakpoint of the Sicilian delta beta-thalassemia. However, the 3' breakpoint was localized between two Pst I sites 4.7 kb 3' of the beta- globin gene, thus ending about 0.7 kb upstream from the 3' breakpoint of the Sicilian delta beta-thalassemia. This results in a 12.5 kb deletion of DNA. It is of interest that the 5' breakpoint of the deletion residues within an AT-rich region which has been proposed as a specific recognition signal for recombination events, while the 3' breakpoint lies within a cluster of L1 repetitive sequences (formerly known as Kpn I family repeats). The presence of the 3' breakpoints of several other deletions within this region of L1 repeats also suggests that such sequences might serve as hot spots for recombination and eventually lead to thalassemia deletions. The similarity of the 5' and 3' breakpoints of these delta beta-thalassemias underscores the putative regulatory role of the deleted and juxtaposed sequences on the expression of the gamma-globin genes in adult life. 相似文献
65.
Shailender Swaminathan Vincent Mor Rajnish Mehrotra Amal N Trivedi 《Health services research》2015,50(3):790-808
ObjectiveIn 2011, the Centers for Medicare and Medicaid Services (CMS) replaced fee-for-service reimbursement for erythropoiesis stimulating agents (ESAs) with a fixed-sum bundled payment for all dialysis-related care and pay-for-performance incentives to discourage maintaining patients'' hematocrits above 36 percent. We examined the impact of the new payment policy on the use of ESAs.ConclusionsCMS''s payment reform for dialysis care reduced the use of ESAs in patients who may not benefit from these agents. 相似文献
66.
67.
68.
James Sargent MD Roya Sohaey MD Neha Trivedi MD 《Journal of clinical ultrasound : JCU》2018,46(5):355-357
Infection of a maternal urachal cyst during pregnancy is rare; Sonography is an important diagnostic tool that can help minimize maternal and fetal complications. We describe the case of a 35‐year‐old multiparous woman presenting in the third trimester with 2 weeks of fever, abdominal pain, and urinary symptoms. Imaging showed a 5‐cm complex anterior midline mass, found intraoperatively to be eroding into the uterus. Sonographic imaging aided in the diagnosis and management of the urachal cyst, and antepartum sonographic measurements of the lower uterine segment helped to counsel regarding a trial of labor. Following treatment, the patient stabilized and had an uncomplicated vaginal delivery. 相似文献
69.
70.
The application of quantitative cytochemistry to study the acinar distribution of enzymatic activities in human liver biopsy sections 总被引:4,自引:0,他引:4
The zonal distribution of enzyme activities was measured by quantitative cytochemistry in cryosections of liver from three normal children and five infants with idiopathic hepatitis of infancy. Optimal conditions for cytochemical reactions were first validated in rat liver and subsequently used in human livers to quantify zonal activities of acid phosphatase (AP), succinate dehydrogenase (SDH), glutamate dehydrogenase (GDH), glucose-6-phosphatase (G6P) and NADPH-dehydrogenase (ND). In normal rat and human livers, activities were greater for SDH and G6P in periportal and for GDH and ND in perivenular hepatocytes, while AP was evenly distributed along the sinusoids. In five infants with idiopathic hepatitis of infancy (IHI), a similar trend of distribution was observed for the two mitochondrial (SDH and GDH) and the two microsomal (G6P and ND) enzymes, although the distribution gradient was less pronounced than, in normal livers. AP showed a mildly greater periportal than perivenular activity. This preliminary study shows that a similar metabolic zonation exists for these enzymes in human livers as is observed in rats. 相似文献