全文获取类型
收费全文 | 21274篇 |
免费 | 1211篇 |
国内免费 | 112篇 |
专业分类
耳鼻咽喉 | 231篇 |
儿科学 | 428篇 |
妇产科学 | 461篇 |
基础医学 | 2740篇 |
口腔科学 | 639篇 |
临床医学 | 1664篇 |
内科学 | 5657篇 |
皮肤病学 | 527篇 |
神经病学 | 1899篇 |
特种医学 | 526篇 |
外科学 | 3312篇 |
综合类 | 110篇 |
现状与发展 | 1篇 |
一般理论 | 4篇 |
预防医学 | 1591篇 |
眼科学 | 403篇 |
药学 | 1068篇 |
中国医学 | 52篇 |
肿瘤学 | 1284篇 |
出版年
2023年 | 159篇 |
2022年 | 309篇 |
2021年 | 837篇 |
2020年 | 368篇 |
2019年 | 723篇 |
2018年 | 848篇 |
2017年 | 486篇 |
2016年 | 493篇 |
2015年 | 570篇 |
2014年 | 786篇 |
2013年 | 1095篇 |
2012年 | 1776篇 |
2011年 | 1682篇 |
2010年 | 973篇 |
2009年 | 899篇 |
2008年 | 1411篇 |
2007年 | 1443篇 |
2006年 | 1368篇 |
2005年 | 1331篇 |
2004年 | 1076篇 |
2003年 | 1019篇 |
2002年 | 962篇 |
2001年 | 136篇 |
2000年 | 78篇 |
1999年 | 135篇 |
1998年 | 144篇 |
1997年 | 144篇 |
1996年 | 118篇 |
1995年 | 120篇 |
1994年 | 104篇 |
1993年 | 84篇 |
1992年 | 66篇 |
1991年 | 63篇 |
1990年 | 41篇 |
1989年 | 40篇 |
1988年 | 40篇 |
1987年 | 39篇 |
1986年 | 44篇 |
1985年 | 46篇 |
1984年 | 46篇 |
1983年 | 23篇 |
1982年 | 30篇 |
1981年 | 44篇 |
1980年 | 29篇 |
1979年 | 42篇 |
1978年 | 36篇 |
1977年 | 21篇 |
1976年 | 30篇 |
1975年 | 23篇 |
1974年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Jorge Guardado Carlos Cotrim Otília Sim?es Sofia Almeida Mário Ialá Luís Lopes Hélder Pereira Manuel Carrageta 《Revista portuguesa de cardiologia》2006,25(4):409-415
INTRODUCTION: Transesophageal echocardiography (TEE) has become increasingly useful in the study of patients with suspected pulmonary thromboembolism. OBJECTIVE: The aim of this study was to prospectively evaluate the usefulness of TEE in the study of the distal part of the left pulmonary artery (LPA) as well as the influence of this procedure on total echocardiographic exam duration. METHODOLOGY: A prospective study in two groups of consecutive patients referred for TEE with a one- year interval between evaluation of Group A: 33 patients, 17 male, mean age 54 +/- 24 years, and Group B: 42 patients, 20 male, mean age 48 +/- 27 years (p = NS). The procedure was considered long when it took more than 3 min to evaluate the distal part of the LPA. RESULTS: In group A we were able to visualize the distal part of the LPA in 24 patients (73%) without significant prolongation of total exam duration in 16 patients (48% of group A). In one of the patients with suspected pulmonary thromboembolism thrombi were only observed in the distal part of the LPA. In group B we were able to visualize the distal part of the LPA in 36 patients (86%) without significant prolongation of total exam duration in 26 patients (61% of group B). CONCLUSIONS: 1. Visualization of the distal part of the LPA was possible in more patients, and with TEE time prolongation in less patients, in group B. These differences can be accounted for by the training of the operator in this technique. 2. The importance of visualization of this part of the LPA in guiding treatment in the subset of patients with pulmonary thromboembolism confirms the usefulness of this specific procedure. 相似文献
32.
Takayuki Takeichi Hideaki Okajima Hiroko Suda Shintarou Hayashida Hironori Iwasaki Manuel Zeledon Ramirez Mikako Ueno Katsuhiro Asonuma Yukihiro Inomata 《Liver transplantation》2005,11(10):1285-1288
Congenital absence of the portal vein (CAPV) is a rare malformation of the splanchnic venous system. Although CAPV is usually detected in the pediatric age group, our patient was a 35-year-old woman. She had been diagnosed with CAPV in 1996 when she was 27 years old. In 1998, she was placed on hemodialysis due to chronic renal failure. After several episodes of encephalopathy in 2002, liver transplantation (LT) was recommended to her and her family. Since there was no suitable living donor candidate, she was put on the waiting list for a deceased donor liver transplant in Japan. In 2004, her ammonia level increased to around 300 microg/dl, and she went into a coma lasting for three days. After recovering from this event, she underwent a living domino transplantation using a whole liver donated by a familial amyloid polyneuropathy (FAP) patient. Her portal vein, which had drained directly into the inferior vena cava (IVC), was transected together with a cuff of the IVC wall and anastomosed to the graft liver portal vein in an end-to-end fashion. In conclusion, liver transplantation proved to be a safe and effective way to save this patient and improve her quality of life. 相似文献
33.
34.
Andressa A.F.L. Maciel Reinaldo B. Ori Manuel B. Braga-Neto Andra B. Braga Eunice B. Carvalho Herene B.M. Lucena Gerly A.C. Brito Richard L. Guerrant Aldo A.M. Lima 《Toxicon》2007,50(8):1027-1040
Vitamin A (retinol), a fat-soluble vitamin, is an essential nutrient for the normal functioning of the visual system, epithelial cell integrity and growth, immunity, and reproduction. Our group has investigated the effect of high doses of oral vitamin A on early childhood diarrhea in our prospective community-based studies from Northeast Brazil and found a beneficial role in reducing the mean duration but not incidence of diarrheal episodes. In this study, we explored the role of retinol supplementation in intestinal cell lines following Clostridium difficile toxin A (TxA) challenge. C. difficile is the most common anaerobic pathogen borne with antibiotic-borne diarrhea and pseudomembranous colitis. Since retinol is critical for the integrity of tight junctions and to modulate the cell cycle, we have focused on changes in transepithelial electrical resistance (TEER) in Caco-2, a more differentiated intestinal cell line, and on models of cell proliferation, migration and viability in IEC-6 cells, an undifferentiated crypt cell line, following TxA injury. In this model, retinol therapy reduced apoptosis, improved cell migration and proliferation, and prevented the reduction in TEER, following C. difficile TxA challenge in a glutamine-free medium. These results suggest the role of retinol in protecting intestinal epithelial barrier function from C. difficile TxA enterotoxic damage. 相似文献
35.
Antonio Gómez Mercedes Salgado Manuel Valladares-Ayerbes Mónica Jorge Ana Carballo Sonia Candamio Pilar Izquierdo Paula Peleteiro Rafael López 《Clinical & translational oncology》2010,12(12):843-848
Objective
The aim of the project was to assess the effectiveness and safety of weekly epoetin-beta (EB) in patients with gastrointestinal cancer (GIC) subjected to concomitant chemoradiotherapy (CCTRT). 相似文献36.
37.
38.
39.
Manuel Sosa P. Saavedra J. del Pino-Montes J. Alegre R. Pérez-Cano G. Martínez Díaz Guerra M. Díaz-Curiel C. Valero M. Muñoz-Torres A. Torrijos J. Mosquera C. Gómez-Alonso GIUMO Study Group 《Journal of clinical densitometry》2005,8(4):430-435
Measurement of ultrasonographic parameters provides information concerning not only bone density but also bone architecture. We investigated the usefulness of ultrasonographic parameters and bone mineral density (BMD) to evaluate the probability of Colles' fracture. Two-hundred eighty-nine postmenopausal women (62.3 +/- 8.7 yr) with (n = 76) and without (n = 213) Colles' fracture were studied. BMD of lumbar spine and proximal femur was evaluated in all women by dual-energy X-ray absorptiometry (DXA) and speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness in the calcaneus were measured by a Sahara ultrasonometer (Hologic). Patients suffering from Colles' fracture had lower values of BMD adjusted by height at the lumbar spine, L2-L4 (0.797 g/cm2 vs 0.860 g/cm2), femoral neck (0.685 g/cm2 vs 0.712 g/cm2 ), SOS (1518 m/sg vs 1525 m/sg), and stiffness (74.6 vs 77.7) (p < 0.05). Nevertheless, BUA values were similar in both groups. After stepwise logistic regression analysis, the area found under receiver operating characteristic (ROC) curves was 0.60 for L2L4 and 0.63 for a formula combining L2L4 and height. Our data suggest that patients suffering from Colles' fracture have lower values of BMD by DXA, SOS, and stiffness. However, the ability of these techniques to discriminate is low because the values for the area under ROC curve are 0.60 for L2-L4 and 0.63 for a formula derived of the combination of L2-L4 and height. 相似文献
40.
Jose M. Fernández-Cebrián Peter Vorwald Kuborn Mar Pardo de Lama Alfonso Sanjuanbenito Dehesa Manuel Nevado Santos Pedro A. Pacheco Martínez Beatriz Fernández-Escudero 《Clinical & translational oncology》2005,7(3):101-109
Colorectal cancer is one of the best studied of all malignant diseases interms of genetics and/or molecular prognostic factors. These factors, and relationships with prognosis, may have important implications especially in the design of surgical and adjuvant chemo-radiotherapy options. However, the true prognostic significance of all known factors has yet to be realised. We have reviewed the literature with specific focus on the role of molecular markers involved in prognosis and the prediction of response to adjuvant treatment. 相似文献