全文获取类型
收费全文 | 7733篇 |
免费 | 439篇 |
国内免费 | 54篇 |
专业分类
耳鼻咽喉 | 74篇 |
儿科学 | 272篇 |
妇产科学 | 182篇 |
基础医学 | 1283篇 |
口腔科学 | 111篇 |
临床医学 | 598篇 |
内科学 | 1883篇 |
皮肤病学 | 179篇 |
神经病学 | 800篇 |
特种医学 | 148篇 |
外科学 | 670篇 |
综合类 | 23篇 |
预防医学 | 669篇 |
眼科学 | 157篇 |
药学 | 586篇 |
中国医学 | 37篇 |
肿瘤学 | 554篇 |
出版年
2024年 | 7篇 |
2023年 | 57篇 |
2022年 | 169篇 |
2021年 | 280篇 |
2020年 | 164篇 |
2019年 | 225篇 |
2018年 | 241篇 |
2017年 | 201篇 |
2016年 | 206篇 |
2015年 | 245篇 |
2014年 | 328篇 |
2013年 | 399篇 |
2012年 | 630篇 |
2011年 | 635篇 |
2010年 | 324篇 |
2009年 | 271篇 |
2008年 | 480篇 |
2007年 | 536篇 |
2006年 | 503篇 |
2005年 | 468篇 |
2004年 | 434篇 |
2003年 | 388篇 |
2002年 | 365篇 |
2001年 | 45篇 |
2000年 | 31篇 |
1999年 | 50篇 |
1998年 | 72篇 |
1997年 | 61篇 |
1996年 | 49篇 |
1995年 | 48篇 |
1994年 | 35篇 |
1993年 | 35篇 |
1992年 | 35篇 |
1991年 | 23篇 |
1990年 | 17篇 |
1989年 | 13篇 |
1988年 | 23篇 |
1987年 | 15篇 |
1986年 | 15篇 |
1985年 | 9篇 |
1984年 | 11篇 |
1983年 | 15篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 9篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1974年 | 5篇 |
排序方式: 共有8226条查询结果,搜索用时 0 毫秒
121.
Montalbano M Pasulo L Sonzogni A Remuzzi G Colledan M Strazzabosco M 《Journal of clinical gastroenterology》2007,41(2):216-220
End-stage liver disease after hepatitis C virus (HCV) infection is the most common indication for liver transplantation, accounting for over 40% of liver transplants performed. Combined liver/kidney transplantation is being performed more frequently, in part because HCV infection may coexist with conditions that damage the kidney, such as diabetes and cryoglobulinemia. Unfortunately, HCV hepatitis and cryoglobulinemia may recur after liver transplantation and adversely affect graft and patient survival. In immunocompetent patients, interferon (IFN) and ribavirin (RBV) combination therapy is often able to control cryoglobulinemic syndrome. Very little data are available on liver transplant recipients, whereas IFN usually is not indicated in kidney transplant recipients because of early reports of steroid-induced rejection after its administration. Successful treatment of cryoglobulinemia with IFN/RBV in recipients of combined liver/kidney transplant has not been previously reported. We treated 1 recipient of a combined liver and kidney transplant with pegylated-IFN/RBV combination therapy. The patient developed HCV recurrence associated with cryoglobulinemia and severe cutaneous peripheral and neurologic manifestations. Treatment with pegylated-IFN-alpha2b and RBV for 12 months cured the cryoglobulinemic vasculitis and allowed the sustained eradication of HCV with no significant changes in kidney function. 相似文献
122.
Mourad-Baars PE Verspaget HW Mertens BJ Mearin ML 《European journal of gastroenterology & hepatology》2007,19(3):213-216
AIM OF THE STUDY: To investigate the seroprevalence of Helicobacter pylori infection in young children from the general population in The Netherlands. METHODS: Determination of IgG antibodies against H. pylori, using an enzyme-linked immunosorbent assay technique [cutoff 0.32 Absorption Index (AI)], in serum from 1258 children who were 2-4 years of age. The serum was obtained from a serum bank of 6127 children who attended the community child healthcare centers in the Dutch province of Zuid-Holland. RESULTS: In general, we found a seroprevalence of 1.2% of H. pylori infection, with a significant difference between the children with parents who were both Dutch (0.5%), and the children with at least one non-Dutch parent (2.6%) (P<0.001). CONCLUSIONS: The prevalence of H. pylori infection in young infants in the general population in The Netherlands is low. Children with at least one non-Dutch parent form a risk group, however, for H. pylori infection in The Netherlands. 相似文献
123.
Expression of ectonucleotidase CD39 by Foxp3+ Treg cells: hydrolysis of extracellular ATP and immune suppression 下载免费PDF全文
124.
Brown adipose tissue (BAT) is involved in rat and mice thermoregulation, and heat produced by BAT depends on the concerted action of thyroid hormones and catecholamines. Little is known about cold-induced thermogenesis in mammals that have little or no BAT, such as rabbits. In these animals, thermogenesis primarily occurs in skeletal muscle. In this work, we have studied the effect of cold acclimation (4 C for 10 d) in normal and hypothyroid rabbits. It is known that hypothyroid rats die after a few hours of cold exposure. We now show that, different from rats, hypothyroid rabbits sustain their body temperature and survive after 10 d cold exposure. When compared with rabbits kept at room temperature, the muscles of cold-exposed rabbits showed a dark red color characteristic of oxidative muscle fibers. According to this pattern, we observed that in both normal and hypothyroid rabbits, cold exposure promotes an increase in oxygen consumption by skeletal muscle mitochondria. Moreover, in red muscle, cold acclimation induces an increase in the expression and activity of sarcoplasmic reticulum Ca(2+) ATPase isoform 1 (SERCA1), one of the muscle enzymes involved in heat production. We conclude that rabbit cold tolerance is probably related to increased muscle oxidative metabolism and heat production by SERCA1 and that these changes are not completely dependent on normal thyroid function. 相似文献
125.
Giuseppe Grosso Antonio Mistretta Stefano Marventano Roberta Ferranti Luisa Mauro Rosario Cunsolo Lidia Proietti Mariano Malaguarnera 《Hepatitis monthly》2012,12(9)
Background
The impact of hepatitis B virus (HBV) vaccination campaigns on HBV epidemiology needs to be evaluated, in order to assess the long-term immunity offered by vaccines against HBV.Objectives
To evaluate the current status of anti-HBV vaccine coverage among healthcare workers (HCWs) in Southern Italy, and to determine the long-term persistence of antibodies to hepatitis B surface antigens (anti-HBs) in such a cohort of subjects.Patients and Methods
A longitudinal, retrospective seroepidemiological survey was conducted among 451 HCWs, who were working at or visiting, the Occupational Health Department of a city hospital, in Catania, Italy, between January 1976 and December 2010.Results
At the 30-year follow-up (mean follow-up 10.15 ± 5.96 years, range 0.74-30), 261 HCWs had detectable anti-HBs titers indicating a persistence of seroprotection of 89.4% (out of 292 anti-HBs positive results, three months after vaccination). An inadequate vaccination schedule was the strongest predictor of antibody loss during follow-up (OR = 8.37 95% CI: 5.41-12.95, P < 0.001). A Kaplan-Maier survival curve revealed that the persistence of anti-HBs 30 years after vaccination, was 92.2% for high responders, while it was only 27.3% for low responders (P = 0.001).Conclusions
A good level of seroprotection persisted in 57.9% of the subjects after 30 years. Factors related to this immunization status confirmed the importance of vaccinating HCWs early in their careers and ensuring an adequate vaccination schedule. However, with particular reference to the low rate of hepatitis B vaccine coverage among HCWs in Southern Italy, the implementation of a new educational intervention as part of an active vaccination program is needed. 相似文献126.
127.
Middle cerebral artery peak systolic and ductus venosus velocity waveforms in the hydropic fetus. 总被引:2,自引:0,他引:2
Erich Cosmi Salvatore Dessole Luisa Uras Giampiero Capobianco Donato D'Antona Alessandra Andrisani Pietro Litta Guido Ambrosini 《Journal of ultrasound in medicine》2005,24(2):209-213
OBJECTIVE: The purpose of this study was to assess whether Doppler assessment of the middle cerebral artery (MCA) peak systolic velocity (PSV) and ductus venosus (DV) velocity waveforms during sonography of hydropic fetuses may specify the cause of fetal hydrops. METHODS: A level II sonographic examination was performed in 16 hydropic fetuses, and the MCA PSV and DV velocity waveforms were assessed. The MCA PSV values divided hydropic fetuses into anemic (group 1) and nonanemic (group 2) fetuses. In group 2 fetuses, the DV was defined as normal or abnormal. Sonographic examination and Doppler assessment of these vessels specified the cause of hydrops and indicated the use of specific investigations for diagnosing the etiology of fetal hydrops. RESULTS: Seven of 16 fetuses had MCA PSV values greater than 1.50 multiples of the median (group 1). Nine of 16 fetuses had normal MCA PSV values (group 2); among them, 7 of 9 had either absent or reversed flow in the DV, and 2 had a normal DV. In group 1, the cause of fetal anemia was investigated by maternal serum tests, and 5 cordocentesis procedures were performed. In group 2, 7 of 9 fetuses had reversed flow in the DV, which suggested a cardiac abnormality confirmed by echocardiography. Five cordocentesis procedures were performed for fetal karyotype, and in 2 fetuses, the cause of hydrops was idiopathic. CONCLUSIONS: Our data suggest that assessment of the MCA PSV and DV velocity waveforms in the hydropic fetus may further our knowledge of the etiology of hydrops and may indicate which investigations among the many available should be used for diagnosing the cause of fetal hydrops. 相似文献
128.
Maria Luisa Cotrina Jane H.-C. Lin Alexandra Alves-Rodrigues Shujun Liu Jiang Li Hooman Azmi-Ghadimi Jian Kang Christian C. G. Naus Maiken Nedergaard 《Proceedings of the National Academy of Sciences of the United States of America》1998,95(26):15735-15740
Forced expression of gap junction proteins, connexins, enables gap junction-deficient cell lines to propagate intercellular calcium waves. Here, we show that ATP secretion from the poorly coupled cell lines, C6 glioma, HeLa, and U373 glioblastoma, is potentiated 5- to 15-fold by connexin expression. ATP release required purinergic receptor-activated intracellular Ca2+ mobilization and was inhibited by Cl− channel blockers. Calcium wave propagation also was reduced by purinergic receptor antagonists and by Cl− channel blockers but insensitive to gap junction inhibitors. These observations suggest that cell-to-cell signaling associated with connexin expression results from enhanced ATP release and not, as previously believed, from an increase in intercellular coupling. 相似文献
129.
Maria Alenita Oliveira Ana Luisa Godoy Fernandes Lucia Ande Santos Maria Amélia dos Santos Carvalho Sonia Maria Faresin Ilka Lopes Santoro 《The Journal of asthma》2013,50(5):407-410
Aim. To study any discriminative properties of SF-36 and QQL-EPM in stable and non-controlled moderate asthmatic patients. Methods. A total of 63 asthmatic patients were assessed regarding asthma symptoms, FEV1 % predicted value, PEF, ED visits and hospitalizations, QQL-EPM and SF-36 questionnaires. Results. QQL-EPM highlighted significance in all domains to distinguish stable from non-controlled patients (p = 0.0001) while SF-36 was only significant in 3 of its 7 domains (p = 0.009). Conclusion. The study showed that the specific quality of life questionnaire for asthma (QQL-EPM) demonstrates better discriminative properties that characterize asthma control when compared with the more generic SF-36 questionnaire. 相似文献
130.
Sabina Luisa Campanelli Giuseppe Casalino Caterina Casavola Vincenzo Moramarco 《Materials》2013,6(12):5923-5941
Friction Stir Welding (FSW) is a solid-state joining process; i.e., no melting occurs. The welding process is promoted by the rotation and translation of an axis-symmetric non-consumable tool along the weld centerline. Thus, the FSW process is performed at much lower temperatures than conventional fusion welding, nevertheless it has some disadvantages. Laser Assisted Friction Stir Welding (LAFSW) is a combination in which the FSW is the dominant welding process and the laser pre-heats the weld. In this work FSW and LAFSW tests were conducted on 6 mm thick 5754H111 aluminum alloy plates in butt joint configuration. LAFSW is studied firstly to demonstrate the weldability of aluminum alloy using that technique. Secondly, process parameters, such as laser power and temperature gradient are investigated in order to evaluate changes in microstructure, micro-hardness, residual stress, and tensile properties. Once the possibility to achieve sound weld using LAFSW is demonstrated, it will be possible to explore the benefits for tool wear, higher welding speeds, and lower clamping force. 相似文献