全文获取类型
收费全文 | 20185篇 |
免费 | 1154篇 |
国内免费 | 151篇 |
专业分类
耳鼻咽喉 | 250篇 |
儿科学 | 525篇 |
妇产科学 | 732篇 |
基础医学 | 2182篇 |
口腔科学 | 579篇 |
临床医学 | 1673篇 |
内科学 | 4009篇 |
皮肤病学 | 416篇 |
神经病学 | 943篇 |
特种医学 | 757篇 |
外国民族医学 | 11篇 |
外科学 | 3508篇 |
综合类 | 364篇 |
现状与发展 | 2篇 |
一般理论 | 11篇 |
预防医学 | 1747篇 |
眼科学 | 576篇 |
药学 | 1861篇 |
中国医学 | 139篇 |
肿瘤学 | 1205篇 |
出版年
2024年 | 17篇 |
2023年 | 267篇 |
2022年 | 801篇 |
2021年 | 1169篇 |
2020年 | 637篇 |
2019年 | 793篇 |
2018年 | 1082篇 |
2017年 | 625篇 |
2016年 | 660篇 |
2015年 | 682篇 |
2014年 | 936篇 |
2013年 | 1104篇 |
2012年 | 1597篇 |
2011年 | 1762篇 |
2010年 | 1000篇 |
2009年 | 719篇 |
2008年 | 1014篇 |
2007年 | 1028篇 |
2006年 | 938篇 |
2005年 | 901篇 |
2004年 | 780篇 |
2003年 | 713篇 |
2002年 | 644篇 |
2001年 | 151篇 |
2000年 | 125篇 |
1999年 | 105篇 |
1998年 | 86篇 |
1997年 | 80篇 |
1996年 | 76篇 |
1995年 | 72篇 |
1994年 | 64篇 |
1993年 | 56篇 |
1992年 | 64篇 |
1991年 | 66篇 |
1990年 | 66篇 |
1989年 | 55篇 |
1988年 | 56篇 |
1987年 | 47篇 |
1986年 | 40篇 |
1985年 | 41篇 |
1984年 | 45篇 |
1983年 | 38篇 |
1982年 | 37篇 |
1981年 | 25篇 |
1980年 | 23篇 |
1978年 | 19篇 |
1977年 | 17篇 |
1976年 | 19篇 |
1974年 | 16篇 |
1973年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Mohamed Eid Fawzy Mohamed Shoukri Walid Hassan Vijayaraghavan Nambiar Miltiadis Stefadouros Charles C Canver 《Catheterization and cardiovascular interventions》2007,69(1):40-46
BACKGROUND: The effect of mitral valve morphology (MVM) on the long-term results of mitral balloon valvuloplasty (MBV) is not well established. The aim of the study was to evaluate the impact of MVM on long-term outcome of MBV. METHODS: Five hundred and eighteen consecutive patients (mean age, 31+/-11 years) who underwent successful MBV were followed up for 0.5-16.5 (mean, 6+/-4.5) years. Patients were divided into two groups according to their mitral echo score (MES) before MBV: group A (n=340; MES8). RESULTS: We report the immediate and long-term clinical and echocardiographic results of the above-mentioned 518 consecutive patients. The mitral valve area was significantly larger in group A than in group B, both immediately after MBV (2.0+/-0.3 vs. 1.82+/-0.3 cm2, respectively; P<0.0001) and also at the last follow-up (1.8+/-0.33 vs. 1.5+/-0.33 cm2, respectively; P<0.0001). Restenosis occurred in 38/340 (11%) in group A vs. 73/178 (41%) in group B (P<0.0001). Actuarial freedom from restenosis at 5, 10, 15 years were 92+/-2%, 85+/-3%, 65+/-6% for group A vs. 72+/-4%, 44+/-5%, 9+/-6% for group B (P<0.001). Event-free survival rates at 5, 10, 15 years for group A were 93+/-1%, 88+/-2%, 66+/-6% vs. 82+/-3%, 59+/-6%, 8+/-7% for group B (P<0.0001). Stepwise Cox multivariate regression analysis identified MES, preprocedure functional class, and postprocedure mitral valve area相似文献
23.
24.
D. Douglas Miller Henry G. Stratmann Leslee Shaw Beaver R. Tamesis Mark D. Wittry Liwa T. Younis Bernard R. Chaitman 《Journal of nuclear cardiology》1994,1(1):72-82
Background
A total of 137 consecutive patients with recent uncomplicated myocardial infarction (n=31) or unstable angina (n=106) were studied to determine the relative prognostic value of predischarge clinical risk stratification and intravenous dipyridamole stress sestamibi (MIBI) myocardial tomography in patients unable to exercise maximally after an acute ischemic coronary event. 相似文献25.
Simon Vinitski Carlos Gonzalez Feroze Mohamed Tad Iwanaga Robert L. Knobler Kamil Khalili John Mack 《Magnetic resonance in medicine》1997,37(3):457-469
Our aim was to develop an accurate multispectral tissue segmentation method based on 3D feature maps. We utilized proton density (PD), T2-weighted fast spin-echo (FSE), and T1-weighted spin-echo images as inputs for segmentation. Phantom constructs, cadaver brains, an animal brain tumor model and both normal human brains and those from patients with either multiple sclerosis (MS) or primary brain tumors were analyzed with this technique. Initially, misregistration, RF inhomogeneity and image noise problems were addressed. Next, a qualified observer identified samples representing the tissues of interest. Finally, k-nearest neighbor algorithm (k-NN) was utilized to create a stack of color-coded segmented images. The inclusion of T1 based images, as a third input, produced significant improvement in the delineation of tissues. In MS, our 3D technique was found to be far superior to that based on any combination of 2D feature maps (P < 0.001). We identified at least two distinctly different classes of lesions within the same MS plaque, representing different stages of the disease process. Further, we obtained the regional distribution of MS lesion burden and followed its changes over time. Neuropsychological aberrations were the clinical counterpart of the structural changes detected in segmentation. We could also delineate the margins of benign brain tumors. In malignant tumors, up to four abnormal tissues were identified: 1) a solid tumor core, 2) a cystic component, 3) edema in the white matter, and 4) areas of necrosis and hemorrhage. Subsequent neurosurgical exploration confirmed the distribution of tissues as predicted by this analysis. 相似文献
26.
Hans J. Biersack Bernd Briele Andreas L. Hotze Peter Oehr Liu Qian Mohamed A. Mekkawy Wei-Jen Shih 《Annals of nuclear medicine》1992,6(3):131-136
Nuclear Medicine offers screening methods for oncology such as bone and bone marrow scintigraphy. During the last two decades, special procedures have gained widespread application. This paper is centered around the “tumor-specific” radiopharmaceuticals. In patients with thyroid cancer, I-131 still plays a significant role. Ga-67 still has its indications in lymphoma, while in other diseases Tl-201 cloride is now the agent of choice. Especially in thyroid cancer, Tl-201 has proved to be a reliable tumor imaging radiopharmaceutical. More recently, Tc-99m MIBI was introduced for tumor imaging. Tc-99m HMPAO may also be used for tumor scintigraphy, especially in brain lesions. In addition, I-123 IMP has successfully been used for imaging malignant melanoma. Another promising field of tumor diagnosis is receptor imaging. In neuroblastoma and malignant pheochromocytoma, I-131/123 mIBG is the radiopharmaceutical of choice and may be considered as a receptor imaging agent also. First clinical results with In-111 octreotide show potentials as somatostatine-receptor radiopharmaceutical in insulinoma, islet cell carcinoma, medullary and lung cancer, while I-123 estradiol needs some improvement until it may be recommended as diagnostic tool in breast cancer. Since 1978, radiolabeled poly- or monoclonal tumor antibodies and their fragments have gained widespread application. Especially the Tc-99m 225.28S melanoma antibody, I-131 or Tc-99m CEA and In-111/I-131 labeled OC-125 antibodies have proven to be of clinical significance in melanoma, colorectal and ovarian cancer. 相似文献
27.
28.
29.
30.
F R Nelson D Holloway A K Mohamed 《Journal of the American Mosquito Control Association》1986,2(3):296-299
In a laboratory study, the insect growth regulator, cyromazine, exerted a high level of biological activity on Aedes aegypti and Culex quinquefasciatus treated in the 4th larval instar. At 1.5 and 1.0 ppm this IGR produced 97 and 99% inhibition of emergence in adult Ae. aegypti, respectively. In Cx. quinquefasciatus, there was 99% inhibition at 1 ppm and complete inhibition at 1.5 ppm. The overall pupal mortality was higher than larval or adult stages of both species. This material induced different types of morphogenetic abnormalities in pupae and adults of the 2 species similar to those induced by other IGRs. However, most abnormalities were observed in the pupal stage. Adverse effects were not detected on the 4 mosquito predator species during the acute or posttreatment tests. 相似文献