全文获取类型
收费全文 | 55703篇 |
免费 | 4863篇 |
国内免费 | 3270篇 |
专业分类
耳鼻咽喉 | 543篇 |
儿科学 | 535篇 |
妇产科学 | 647篇 |
基础医学 | 7165篇 |
口腔科学 | 1099篇 |
临床医学 | 6870篇 |
内科学 | 8705篇 |
皮肤病学 | 763篇 |
神经病学 | 2985篇 |
特种医学 | 2473篇 |
外国民族医学 | 37篇 |
外科学 | 6141篇 |
综合类 | 7755篇 |
现状与发展 | 7篇 |
一般理论 | 2篇 |
预防医学 | 3504篇 |
眼科学 | 1559篇 |
药学 | 5559篇 |
44篇 | |
中国医学 | 2688篇 |
肿瘤学 | 4755篇 |
出版年
2024年 | 147篇 |
2023年 | 785篇 |
2022年 | 2170篇 |
2021年 | 2899篇 |
2020年 | 1933篇 |
2019年 | 1819篇 |
2018年 | 1956篇 |
2017年 | 1664篇 |
2016年 | 1788篇 |
2015年 | 2591篇 |
2014年 | 3218篇 |
2013年 | 2905篇 |
2012年 | 4637篇 |
2011年 | 4746篇 |
2010年 | 3026篇 |
2009年 | 2470篇 |
2008年 | 3209篇 |
2007年 | 3064篇 |
2006年 | 2846篇 |
2005年 | 2589篇 |
2004年 | 1878篇 |
2003年 | 1717篇 |
2002年 | 1501篇 |
2001年 | 1205篇 |
2000年 | 1227篇 |
1999年 | 1163篇 |
1998年 | 648篇 |
1997年 | 685篇 |
1996年 | 541篇 |
1995年 | 451篇 |
1994年 | 367篇 |
1993年 | 255篇 |
1992年 | 336篇 |
1991年 | 249篇 |
1990年 | 216篇 |
1989年 | 188篇 |
1988年 | 148篇 |
1987年 | 134篇 |
1986年 | 105篇 |
1985年 | 90篇 |
1984年 | 51篇 |
1983年 | 50篇 |
1982年 | 22篇 |
1981年 | 24篇 |
1980年 | 13篇 |
1979年 | 23篇 |
1978年 | 11篇 |
1973年 | 11篇 |
1971年 | 9篇 |
1969年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
71.
18例恶性苗勒混合瘤临床病理分析 总被引:1,自引:0,他引:1
目的:探讨女性生殖系统恶性苗勒混合瘤(MMMT)的临床与病理特征。方法:对18例女性生殖系统MMMT进行光镜观察及免疫组化染色,结合临床资料进行分析,对9例进行了术后随访。结果:各部位MMMT的形态特征相似,均含有上皮及间叶两种组织成分,相互间有穿插和移行变化,组织成分形态多样,免疫组化有助于判断。恶性度与异型性、核分裂数及出血坏死程度有关。预后与临床分期有关。化疗有效。结论:MMMT的诊断主要依据组织形态学,预后与临床分期有关。 相似文献
72.
C. H. Suh C. H. Lee J. Lee C. H. Song C. W. Lee W. H. Kim S. K. Lee 《Journal of Korean medical science》1998,13(1):39-43
Inflammatory bowel disease (IBD) is commonly associated with arthritic manifestations. They are divided into three clinical categories; peripheral arthritis, spondylitis, and sacroiliitis. To evaluate the incidence of arthritis associated with IBD in Korea, we retrospectively reviewed one hundred and twenty-nine patients with IBD, 77 with ulcerative colitis (UC) and 52 with Crohn''s disease (CD). Arthritis occurred in twenty-two patients (17.1%); 15 with UC(19.6%), 7 with CD (13.5%). Patients with arthritis had more active inflammations and all were seronegative except one patient. Peripheral arthritis was found in twenty patients (15.5%) and more common in UC (19.6%) than in CD (9.6%). Joint involvements tended to be monoarticular or pauciarticular, and most frequently developed in the knee and ankle. Spondylitis was diagnosed in one patient (1.6%) who showed HLA B27 positivity. Radiographic sacroiliitis was observed in eight patients (6.2%) who revealed HLA B27 negativity. Both peripheral arthritis and sacroiliitis were found in six patients (4.6%). In CD, arthritis occurred in 20% of the patients with colonic involvement but in none of the patients without colonic involvement. In conclusion, arthritis was frequent in patients with IBD. Peripheral arthritis was more common in patients with UC than CD. All the patients with CD and arthritis had colonic involvement. 相似文献
73.
Mouse embryonic diastema region is an ideal site for the development of ectopically transplanted tooth germ. 总被引:1,自引:0,他引:1
The anterior eye chamber and the kidney capsule of the mouse have been traditionally used for long-term culture of tooth germ grafts. However, although these sites provide an excellent growth environment, they do not represent real in situ sites for the development of a grafted tooth germ. Here, we describe a protocol to transplant a tooth germ into the mandibular diastema region of mouse embryos using exo utero surgery. Our results demonstrate that the mouse embryonic diastema region represents a normal physiological environment for the development of transplanted tooth germs. Transplanted tooth germs developed synchronically with and became indistinguishable from the endogenous ones. These ectopic teeth were vascularized and surrounded with nerve fibers, and were able to erupt normally. Thus, the exo utero transplantation approach will provide a new avenue to study tooth development and regeneration. 相似文献
74.
Yong D Lim JG Choi JR Park Q Yang CH Choi SH Jeong HJ Song KS 《Yonsei medical journal》2000,41(1):136-139
Klinefelter syndrome (KS) is often associated with various neoplasms, especially germ cell tumors. Mediastinum is the most favored site of extragonadal germ cell tumors with KS, which is somewhat different from those without KS. The retroperitoneal germ cell tumor in KS is very rare. A five-month-old boy with an abdominal mass was found to have a retroperitoneal tumor. After surgical removal, he was diagnosed to have mature cystic teratoma. Cytogenetic study of his peripheral lymphocytes revealed that his karyotype was consistent with KS. This case suggests that patients with KS might be at risk of having germ cell tumors in sites other than mediastinum. It also suggests that all cases with these tumors should be screened for the presence of karyotypic abnormalities, and it might help to assess the exact correlation between germ cell tumors and KS, and to treat them accordingly. 相似文献
75.
Arterial intima proteins were extracted by 9 M urea from matching histologically atheroma-free areas of 27 human thoracic aortas of both sexes from younger (15-34) and older (35-82) age groups and studied after separation by high-resolution two-dimensional polyacrylamide gel electrophoresis. Seventeen specific protein groups on each gel were identified according to their relative charges and molecular weights and their distribution in the two age groups compared. Some plasma-derived proteins occurred rarely in young aortas while they were consistently found in those from older cases, i.e., protein group 4 (alpha 1-antichymotrypsin) 1/13 (8%) vs 12/14 (86%), group 7 (haptoglobin beta-chain) 1/13 (8%) vs 13/14 (93%) and groups 6 and 9 (IgG chains) 3/13 (23%) vs 9/14 (64%), respectively. Other plasma-derived proteins such as group 3 (albumin) and 5 (alpha 1-antitrypsin) were identified in all samples of both age groups but their expression in the aortic intima increased with age. Proteins which are typically found intracellularly such as those from groups 11 (actin), 12 (cytoskeleton proteins), and 13 (tropomyosin-like proteins) appeared in samples of intima of both age groups but were less apparent in older specimens. These studies suggest that the changes in aortic intima protein distribution in the absence of atherosclerosis closely correlate with histological changes such as intimal thickening often found with aging, providing new sensitive markers of vascular senescence. 相似文献
76.
神经导航中脑组织变形补偿的点云处理 总被引:1,自引:0,他引:1
有限元方法是解决神经导航中脑组织变形的重要方法,需要手术过程中的脑皮层信息作为其边界条件.本文通过非结构点云进行了脑皮层信息的表示,并通过对其进行处理来获取有限元方法的边界条件.点云处理包括纹理映射、分割、简化和去噪,其中非结构点云的简化与去噪采用了改进的基于表面特性k邻域的聚类方法.实验结果证明所采用的点云处理方法是可靠的. 相似文献
77.
Oxidative stress has been implicated in several diseases, including cancer. Oxidants induce oncogenes and their products associated with cell growth. Even though epidemiological studies implicate oxidants in promoting cancer, there is still a lack of in vivo evidence for the same. In this study, we measured the levels of myeloperoxidase (MPO), an enzyme associated with oxidation and autoantibodies to lipid peroxide-modified protein (LOOH-RSA), in the plasma of subjects with gynecological cancers. The gynecological cancer subjects (n = 201) had higher plasma MPO and LOOH-RSA levels compared with control subjects (n = 60). Immunohistochemical analysis of tissues revealed that immunostaining for MPO and LOOH-RSA was higher in cancer tissues compared with controls. The staining was specific to cell types and not ubiquitously present. Neutrophils, monocytes/macrophages, and natural killer cells have been proposed to play a role in cancer promotion and progression. This study proposes a role for oxidative stress and especially MPO in cancer. 相似文献
78.
Ji-Ying Song Cornelis J. F. Van Noorden Wilma M. Frederiks 《Virchows Archiv : an international journal of pathology》1997,430(3):253-260
Intermediate filaments (IF) maintain the structural and functional integrity of cells. To investigate whether IF change as a consequence of increased mechanical pressure and what the significance of such alterations is for the integrity of hepatocytes, we investigated alterations of IF in rat liver following common bile duct ligation (CBDL). Immunofluorescence of cytokeratin 18 was performed on extracted cryostat sections which were also used for electron microscopy. Ultrathin sections of mildly extracted liver tissue were applied to reveal the relationship between IF and intercellular junctions and cytoplasmic organelles. Our results showed that hepatocellular IF underwent striking changes during CBDL. The so-called pericanalicular sheath disappeared and IF were rigidly rearranged at the cell periphery, appearing as honeycomb-like structures. Increased amounts of IF were found in close association with increased numbers of desmosomes at the lateral membranes of hepatocytes, and electron-dense desmosome-like bodies were even observed in the ectoplasm at bile canaliculi. Rearrangement of IF in the cytoplasm resulted in segregation of subcellular compartments. The increased density of the IF network and desmosomes are compensatory mechanisms of hepatocytes to resist increased mechanical load and disperse the tension. However, the intracellular rearrangement of IF leading to segregation of subcellular compartments may also have distinct effects on hepatocellular metabolic functions. 相似文献
79.
BACKGROUND: Haptoglobin polymorphism is associated with the prevalence of infections, autoimmune diseases, cardiovascular diseases, and other disorders. Congenital haptoglobin deficiency is associated with anaphylactic transfusion reactions in anhaptoglobinaemic patients with antihaptoglobin antibody. AIMS: To investigate haptoglobin genotypic distribution (including the Hp(0) allele) and associated serum haptoglobin concentrations in Koreans. METHODS: Five hundred and nine healthy Korean adults were randomly selected. Two methods were used: haptoglobin genotyping based on a polymerase chain reaction (PCR) system that exploited the structural difference of the Hp(1) and Hp(2 )alleles, and another PCR method that detected haptoglobin gene deletion by amplification of the junctional region of the Hp(0) allele. Serum haptoglobin concentrations were measured by nephelometry. RESULTS: The haptoglobin genotypes of 509 subjects were as follows: Hp(1)Hp(1), 7.1%; Hp(2)Hp(1), 37.7%; Hp(2)Hp(2), 49.3%; Hp(0)Hp(1), 2.2%; Hp(0)Hp(2), 3.5%; Hp(0)Hp(0), 0.2%. The gene frequency of Hp(0) in Koreans was calculated to be 0.031. Significant differences were seen among the concentrations of each haptoglobin genotype (Kruskal-Wallis test). Hp(0)Hp(2), but not Hp(0)Hp(1), was associated with hypohaptoglobinaemia. CONCLUSIONS: PCR methods for differentiating between haptoglobin genotypes, including the Hp(0) allele, may be useful in a broad spectrum of basic studies and clinical examinations. 相似文献
80.
Chung JP Chi SW Park YN Lee SJ Song SY Lee KS Chung JB Lee SI Kang JK Kim KW Chi HS 《Yonsei medical journal》2000,41(4):528-532
Intraductal papillary mucinous tumor (IPMT) of the pancreas, a lesion consisting of mucin-producing cells with neoplastic potential, is characterized by duct ectasia, mucin hypersecretion, often extensive papillary intraductal growth, varying degrees of cytologic atypia, and relatively indolent growth. The clinical presentation of IPMT of the pancreas is characterized by chronic or recurrent attacks of abdominal discomfort often in association with low level pancreatic enzyme elevations. Less commonly these lesions may be detected as asymptomatic radiographic abnormalities. Interestingly, a case of a minute IPMT (2 mm in height and 7 mm in length, adenoma) in the main pancreatic duct presenting with acute pancreatitis in a 55 year-old man has been reported in the Japanese literature. Recently, we also experienced a case of a minute IPMT in a branch pancreatic duct causing repeated bouts of acute pancreatitis in a 75 year-old man. A filling defect at the neck of the main pancreatic duct seen on an endoscopic retrograde pancreatogram performed after recovery of the second attack of acute pancreatitis led the patient to undergo an exploratory laparotomy. After a near-total pancreatectomy was carried out, a minute (3 x 7 mm) IPMT of borderline malignancy was discovered in a branch duct at the head portion near the pancreatic neck without any lesions in the main pancreatic duct. Surprisingly, despite the resective surgery the patient died of carcinomatosis 8.5 months after the operation. We herein report a case of a minute but aggressive IPMT of the pancreas with a review of the literature. 相似文献