全文获取类型
收费全文 | 20138篇 |
免费 | 2500篇 |
国内免费 | 450篇 |
专业分类
耳鼻咽喉 | 119篇 |
儿科学 | 152篇 |
妇产科学 | 55篇 |
基础医学 | 3066篇 |
口腔科学 | 494篇 |
临床医学 | 2447篇 |
内科学 | 1423篇 |
皮肤病学 | 45篇 |
神经病学 | 923篇 |
特种医学 | 1863篇 |
外国民族医学 | 1篇 |
外科学 | 4570篇 |
综合类 | 2178篇 |
预防医学 | 2259篇 |
眼科学 | 110篇 |
药学 | 1101篇 |
3篇 | |
中国医学 | 1830篇 |
肿瘤学 | 449篇 |
出版年
2024年 | 68篇 |
2023年 | 707篇 |
2022年 | 971篇 |
2021年 | 1102篇 |
2020年 | 893篇 |
2019年 | 789篇 |
2018年 | 898篇 |
2017年 | 617篇 |
2016年 | 917篇 |
2015年 | 1223篇 |
2014年 | 1553篇 |
2013年 | 1540篇 |
2012年 | 1036篇 |
2011年 | 971篇 |
2010年 | 903篇 |
2009年 | 905篇 |
2008年 | 716篇 |
2007年 | 555篇 |
2006年 | 442篇 |
2005年 | 464篇 |
2004年 | 837篇 |
2003年 | 319篇 |
2002年 | 266篇 |
2001年 | 226篇 |
2000年 | 148篇 |
1999年 | 146篇 |
1998年 | 237篇 |
1997年 | 318篇 |
1996年 | 317篇 |
1995年 | 252篇 |
1994年 | 386篇 |
1993年 | 265篇 |
1992年 | 284篇 |
1991年 | 274篇 |
1990年 | 262篇 |
1989年 | 184篇 |
1988年 | 199篇 |
1987年 | 90篇 |
1986年 | 125篇 |
1985年 | 122篇 |
1984年 | 98篇 |
1983年 | 66篇 |
1982年 | 122篇 |
1981年 | 81篇 |
1980年 | 47篇 |
1979年 | 46篇 |
1978年 | 26篇 |
1977年 | 29篇 |
1976年 | 17篇 |
1975年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
板股韧带的MRI研究及临床意义 总被引:1,自引:0,他引:1
目的 明确板股韧带正常MRI表现 ,建立由它所致假撕裂与外侧半月板后角真撕裂的鉴别方法。资料与方法 采用 6 0侧正常膝进行矢状和冠状位MR扫描 ,观察板股韧带的MRI表现。结果 板股韧带显示率为88.3% (5 3侧 ) ,其中板股前韧带为 2 6 .7% (16侧 )、板股后韧带为 86 .7% (5 2侧 )和两条韧带同时存在为 2 3.3% (14侧 )。板股韧带在矢状像上表现为位于后交叉韧带前或后方的类圆形或短棒状低信号结构 ,而在冠状像上表现为自外侧半月板后角至股骨内侧髁外侧面的条带样低信号结构。在矢状像上 ,5 2 .8% (2 8/5 3)板股韧带与外侧半月板后角之间显示出一线样高信号 ,被称为假撕裂 ,易与外侧半月板后角撕裂混淆。但假撕裂仅有两种走行方向即后下斜行 (2 1/2 8)或垂直方向 (7/2 8)。结论 根据假撕裂位置、方向以及冠状像和连续矢状面的观察 ,可正确区分外侧半月板后角真假撕裂 相似文献
62.
Abstract Closed suction drainage systems are commonly used in orthopaedic surgery, particularly in joint arthroplasty. The rationale
for the use of drains is a theoretical reduction of wound haematomas and infection. However the benefit of using drains after
total hip or knee arthroplasty is controversial. Several reports have shown that the use of drains does not reduce infection
and morbidity and is an unnecessary and potentially dangerous practice. In fact most studies highlighted that at best their
use appears to make no difference to important clinical outcomes. Recently a metaanalysis raised the question about the usefulness
of closed suction drainage again, concluding that it has no major benefits. The purpose of this study was to review the evidences
available concerning the utility of closed suction drainage outlining that this practice is not supported by clinical evidence. 相似文献
63.
Melanoses of the gastrointestinal tract 总被引:4,自引:0,他引:4
Electronmicroscopy and electron probe energy dispersive X-ray analysis studies have substantially contributed to our understanding of the various gastrointestinal tract melanoses. The nature of the pigment granules which occur in the various melanoses is discussed; their pattern of distribution in melanosis coli, melanosis ilei, melanosis duodeni and melanosis oesophagi is summarized and current knowledge of the aetiology and pathogenesis of these conditions is reviewed. Brief mention is also made of other examples of lipofuscin pigmentation, and a case of haemosiderosis ilei is described. 相似文献
64.
Nodular hyperplasia surrounding fibrolamellar carcinoma 总被引:2,自引:0,他引:2
We report a case of acetaminophen-induced liver necrosis in a 14-year-old girl. At autopsy, a 9 cm subcapsular nodule was present in the right lobe of the liver which showed distinct zonation: a central greyish white area of fibrolamellar carcinoma with a peripheral fleshy, tan-coloured rim ranging from 1 to 2 cm in thickness. This peripheral zone consisted of nodular, hyperplastic parenchyma resembling the changes seen in focal nodular hyperplasia, and stood out from the adjacent necrotic parenchyma. The sparing of this zone from the deleterious effects of acetaminophen provides indirect evidence of a predominantly arterial rather than portal blood supply to this region. The arterial supply was most probably derived from the tumour vasculature and may explain the parenchymal hyperplasia sometimes reported adjacent to a fibrolamellar carcinoma. Awareness of this phenomenon is essential when evaluating a needle biopsy, as sampling of this region may lead to a false negative diagnosis. 相似文献
65.
Joen-Rong sheu Chao-Hsin Lin Jih-Luan chung Che-Ming Teng Tur-Fu Huang 《Thrombosis research》1992,66(6):679-691
Triflavin, an Arg-Gly-Asp (RGD)-containing peptide, purified from snake venom of Trimeresurus flavoviridis, inhibits human platelet aggregation through the blockade of fibrinogen binding to fibrinogen receptors associated with glycoprotein IIb/IIIa complex. In this report, we examined the effect of triflavin on tumor cells (human hepatoma J-5)-induced platelet aggregation (TCIPA) of heparinized platelet-rich plasma (PRP). ADP-scavenger agents, apyrase (10 U/ml) and creatine phosphate (5 mM)/creatine phosphokinase (5 U/ml) did not inhibit TCIPA while hirudin (5u/ml) completely inhibited it. J-5 cells initially induced platelet aggregation, then blood coagulation occurred. J-5 cells concentration-dependently shortened the recalcification time of normal as well as Factor VIII, IX-deficient human plasmas, while it was inactive at shortening the recalcification time of Factor VII-deficient plasma, suggesting J-5 cells induced platelet aggregation through activation of extrinsic pathway, leading to thrombin formation as evidenced by the amidolytic activity on S-2238 by expressing tissue factor-like activity. Triflavin inhibited TCIPA in a dose-dependent manner (IC50, 0.02 μM). When compared on molar ratio, triflavin was approximately 30,000 times more potent than GRGDS (IC50,0.58 mM). On the other hand, GRGES showed no significant effect on TCIPA, even its concentration was raised to 4 mM. Additionally, the monoclonal antibodies, raised against glycoprotein IIb/IIIa complex (i.e., 7E3 and 10 E5) inhibited J-5 TCIPA. In conclusion, we suggest the inhibitory effect of triflavin on J-5 TCIPA may be chiefly mediated by the binding of triflavin to the fibrinogen receptor associated with glycoprotein IIb/IIIa complex on platelet surface membrane. 相似文献
66.
Leon A. Weisberg Jack Greenberg Antonio Stazio 《Computerized medical imaging and graphics》1988,12(6):379-383
The clinical and computerized tomographic (CT) findings in 10 patients with cerebral toxoplasmosis are reviewed. All patients with cerebral toxoplasmosis were homosexuals and/or intravenous drug users, and all patients had other manifestations of AIDS. Two presented with focal seizures, 4 presented with focal neurological deficit which progressively worsened, and 4 had evidence of diffuse neurological dysfunction (altered consciousness, generalized seizures). CT showed a single lesion in 3 patients and multiple lesions in 7 patients. Two patients had hypodense nonenhancing lesions(s). Eight patients had hypodense lesions with peripheral or nodular enhancement. The lesions were more commonly located in the cerebral hemispheres and subcortical gray matter nuclear masses (thalamus, basal ganglia). The finding of a hypodense lesion with a central slightly hyperdense noncalcified region that showed dense nodular homogeneous enhancement was quite characteristic of cerebral toxoplasmosis, but this pattern may also be seen in other neurological conditions including brain lymphomas. 相似文献
67.
The phosphorylation patterns of isolated red blood cell (RBC) membranes labeled with [ γ-32p]ATP are altered by Zn++ ions. Zn++ ions caused an increased phosphate incorporation into a 72 KDa protein and several proteins in the 40–60 KDa region and a decrease in the labeling of a 53 KDa protein. The 72 KDa and 53 KDa proteins have been identified as protein 4.2 and a protease-cleaved fragment of protein 3, respectively. Evidence suggests that the changes in phosphorylation pattern may be due to the stimulation of endogenous membrane alkaline phosphatase(s). Our results suggest that Zn++, at physiological concentrations in the intact erythrocyte, could modulate the phosphorylation of selected proteins which may regulate their association in the cytoskeletal network. 相似文献
68.
69.
We report a case of ectopic ectodermal structures in the ectocervix of a 51-year-old female. Sebaceous glands and numerous abnormal hair follicles were present in the stroma of an otherwise normal cervix. 相似文献
70.
M.H. THERKILDSEN N. CHRISTENSEN L.J. ANDERSEN S. LARSEN M. KATHOLM 《Histopathology》1992,21(2):167-171
Malignant transformation of a benign Warthin's tumour (adenolymphoma) is extremely rare. The light microscopic and ultrastructural features of an adenocarcinoma arising in a Warthin's tumour in the parotid gland are described. Light microscopy demonstrated a transition zone from the benign to the malignant component, and the malignant cells revealed oncocytic features by both light- and electronmicroscopy. 相似文献