全文获取类型
收费全文 | 7077篇 |
免费 | 384篇 |
国内免费 | 141篇 |
专业分类
耳鼻咽喉 | 107篇 |
儿科学 | 176篇 |
妇产科学 | 121篇 |
基础医学 | 933篇 |
口腔科学 | 501篇 |
临床医学 | 522篇 |
内科学 | 1672篇 |
皮肤病学 | 161篇 |
神经病学 | 611篇 |
特种医学 | 445篇 |
外国民族医学 | 1篇 |
外科学 | 707篇 |
综合类 | 59篇 |
一般理论 | 1篇 |
预防医学 | 679篇 |
眼科学 | 70篇 |
药学 | 510篇 |
中国医学 | 75篇 |
肿瘤学 | 251篇 |
出版年
2023年 | 59篇 |
2022年 | 123篇 |
2021年 | 214篇 |
2020年 | 136篇 |
2019年 | 174篇 |
2018年 | 226篇 |
2017年 | 134篇 |
2016年 | 211篇 |
2015年 | 208篇 |
2014年 | 289篇 |
2013年 | 346篇 |
2012年 | 472篇 |
2011年 | 529篇 |
2010年 | 308篇 |
2009年 | 219篇 |
2008年 | 379篇 |
2007年 | 387篇 |
2006年 | 334篇 |
2005年 | 302篇 |
2004年 | 223篇 |
2003年 | 192篇 |
2002年 | 156篇 |
2001年 | 146篇 |
2000年 | 147篇 |
1999年 | 120篇 |
1998年 | 121篇 |
1997年 | 119篇 |
1996年 | 119篇 |
1995年 | 91篇 |
1994年 | 70篇 |
1993年 | 79篇 |
1992年 | 66篇 |
1991年 | 84篇 |
1990年 | 62篇 |
1989年 | 96篇 |
1988年 | 72篇 |
1987年 | 79篇 |
1986年 | 47篇 |
1985年 | 69篇 |
1984年 | 32篇 |
1983年 | 31篇 |
1982年 | 27篇 |
1981年 | 24篇 |
1980年 | 33篇 |
1979年 | 15篇 |
1978年 | 26篇 |
1977年 | 25篇 |
1976年 | 32篇 |
1975年 | 30篇 |
1968年 | 16篇 |
排序方式: 共有7602条查询结果,搜索用时 31 毫秒
21.
22.
Raoul JL; Bourguet P; Bretagne JF; Duvauferrier R; Coornaert S; Darnault P; Ramee A; Herry JY; Gastard J 《Radiology》1988,168(2):541-545
Biodistribution of iodine-131-labeled Lipiodol Ultra-Fluide (I-131 LUF) injected into the hepatic artery was studied scintigraphically in 47 patients with hepatocellular carcinoma (n = 23), hepatic metastases (n = 14), or normal livers (n = 10). The investigation was extremely well tolerated. I-131 LUF concentrated mainly in the liver (L) and the lungs (l), with L/L + l activity ratios greater than 75% for all three groups of patients. I-131 LUF distribution was homogeneous in normal livers and heterogeneous in cirrhotic livers. I-131 LUF concentrated in the tumor with a tumorous (T) to nontumorous (NT) activity ratio (T/NT) of 4.3 +/- 3.6 for hepatocellular carcinoma and 2.4 +/- 0.7 for hepatic metastases. The effective half-life of I-131 LUF is more than 4.5 days for the three groups. It was eliminated mainly through the urine. Clearance from tumor is slower than from normal liver, as shown by the increase in T/NT at day 18. Biodistribution did not change in patients who had a second injection, which indicates that there is no saturation phenomenon. The results of this study suggest that LUF may be considered as a potential carrier vehicle for therapeutic agents. 相似文献
23.
Eduardo Domínguez-Adame Lanuza Encarnación Jiménez Andrade Antonio Rodríguez Fernández Jaime Medina Díez 《Clinical & translational oncology》2005,7(2):78-80
Primary linitis plastica of the rectum is an infrequent and unusual rectal carcinoma. We report a new case that presented clinically as a haemorrhoidal syndrome. We comment on the characteristics--clinical picture and histopathology--of this uncommon presentation of rectal tumour, as well as its clinical history and prognosis taking into account that the literature consulted indicated the unusualness of primary linitis plastica of the rectum. 相似文献
24.
Dominik Zumsteg Danielle M Andrade Richard A Wennberg 《Clinical neurophysiology》2006,117(6):1380-1387
OBJECTIVE: We have investigated the cortical sources and electroencephalographic (EEG) characteristics of small sharp spikes (SSS) by using statistical non-parametric mapping (SNPM) of low resolution electromagnetic tomography (LORETA). METHODS: We analyzed 7 SSS patterns (501 individual SSS) in 6 patients who underwent sleep EEG studies with 29 or 23 scalp electrodes. The scalp signals were averaged time-locked to the SSS peak activity and subjected to SNPM of LORETA values. RESULTS: All 7 SSS patterns (mean 72 individual SSS, range 11-200) revealed a very similar and highly characteristic transhemispheric oblique scalp voltage distribution comprising a first negative field maximum over ipsilateral lateral temporal areas, followed by a second negative field maximum over the contralateral subtemporal region approximately 30 ms later. SNPM-LORETA consistently localized the first component into the ipsilateral posterior insular region, and the second component into ipsilateral posterior mesial temporo-occipital structures. CONCLUSIONS: SSS comprise an amalgam of two sequential, distinct cortical components, showing a very uniform and peculiar EEG pattern and cortical source solutions. As such, they must be clearly distinguished from interictal epileptiform discharges in patients with epilepsy. SIGNIFICANCE: The awareness of these peculiar EEG characteristics may increase our ability to differentiate SSS from interictal epileptiform activity. The finding of a posterior insular source might serve as an inspiration for new physiological considerations regarding these enigmatic waveforms. 相似文献
25.
Lucia Carvalho Monica Lipay Francisco Belfort Ivan Santos Joyce Andrade Alessandra Haddad Flavia Brunstein Lydia Ferreira 《Journal of plastic, reconstructive & aesthetic surgery》2006,59(9):961-968
BACKGROUND: Telomerase activity (TA) is believed to play a role in the regulation of senescence and to limit the number of cell divisions. The deregulation of telomerase appears to contribute to oncogenesis and the formation of immortal cell lines. As a result, it is believed that it could be used as a prognostic marker in melanoma. METHODS: TA was assayed by the polymerase chain reaction PCR-ELISA-based telomeric repeat amplification protocol (TRAP assay). One hundred and eight samples were distributed in four histological groups: 30 samples from primary cutaneous melanomas, 24 from peritumoural skin sites, 28 from benign melanocytic lesions, and 26 from normal skin sites as a control. RESULTS: TA was different among the four tested groups (Kruskall-Wallis test p<0.001), and increasing values of TA were observed progressing from normal skin to benign and then to malignant lesions. Among melanoma samples, there was a significant association between TA and ulceration (p=0.025), TA and vascular invasion (p=0.018) and TA and mitotic rate (p=0.029) (Mann-Whitney test). A linear regression analysis showed significant associations between the increase of TA with Breslow thickness (p=0.004) and the presence of satellites (p=0.002). CONCLUSIONS: We observed that TA had increased from control skin to peritumoural skin, and then to benign melanocytic lesions and finally to melanoma, suggesting tumour progression. TA showed higher values in the presence of some important histopathologic parameters related to poor prognosis in cutaneous melanoma such as ulceration, vascular invasion, satellites, high rates of mitosis, and in thicker tumours. 相似文献
26.
Cristiano Feijó Andrade Thomas K. Waddell Shaf Keshavjee Mingyao Liu 《American journal of transplantation》2005,5(5):969-975
Traditionally, the recognition and tolerance of transplanted grafts has been considered to be within the realm of the adaptive immune system. Innate immunity, on the other hand, as the first line of host defense, plays a role in fighting against invading microorganisms. Recently, with the discovery of the Toll-like receptors (TLRs), the role of innate immune responses in the control of adaptive immunity has become a new area of interest. Emerging evidence suggests that in addition to responding to pathogen-associated molecular patterns of microorganisms, TLRs can be activated by endogenous ligands, expressed by mammalian cells. These 'danger signals' may participate in ischemia-reperfusion related organ damage and subsequently influence function and survival of transplanted grafts. Furthermore, it has been suggested that adaptive immune responses can enhance the acute inflammatory responses controlled by innate immunity in organ transplantation. This review addresses the potential involvement of TLRs in different stages of organ transplantation. Intriguing and controversial findings are presented and discussed in order to stimulate more attention to this emerging and potentially important area of research in organ transplantation. 相似文献
27.
Alberto J Espay Danielle M Andrade Richard A Wennberg Anthony E Lang 《Epileptic Disord》2005,7(3):227-230
Angelman syndrome is a neurogenetic disorder resulting in refractory epilepsy and profound psychomotor retardation in its most prevalent form, caused by deletion of maternal chromosome 15q11-13. We report the case of a 29-year-old, mentally retarded man with unusual electroencephalographic changes during periods of atypical absence status epilepticus, a previously unreported manifestation of the usually milder, drug-responsive epilepsy associated with Angelman syndrome due to the UBE3A mutation.[Published with video sequences]. 相似文献
28.
29.
R Mokni A Chakar F Bleiberg-Daniel JL Mahu PA Walravens P Chappuis J Navarro D Lemonnier 《Acta paediatrica (Oslo, Norway : 1992)》1993,82(6-7):539-543
Biochemical markers of nutritional status (albumin, transthyretin, insulin-like growth factor-I and zinc) were measured in slowly growing two- to five-year-old, low-income Parisian children whose weight-for-height or height-for-age z scores (WHZ or HAZ) were between — 1 and — 2 SD of the NCHS median. The results were compared to controls who were matched for age, sex, and ethnic origin with WHZ and HAZ between — 1 and + 2 SD. Mean serum levels of transthyretin, albumin and insulin-like growth factor-I and mean plasma zinc concentrations were significantly lower in the growth-impaired children than in the controls ( p = 0.002, p = 0.006, p = 0.015, and p = 0.035, respectively). While the height-retarded children had low mean serum insulin-like growth factor-I values, the weight-retarded subjects had decreased levels of albumin, transthyretin and zinc when compared to controls. Lower mean levels of nutritional markers in healthy, slowly growing children suggest that inadequate dietary intakes of zinc, protein and/or energy may result in marginal delays in weight and height gains. 相似文献
30.
JI Elizalde ; J Clemente ; JL Marin ; J Panes ; B Aragon ; A Mas ; JM Pique ; J Teres 《Transfusion》1997,37(6):573-576
BACKGROUND: Equilibration of hemoglobin concentration after transfusion has been estimated to take about 24 hours, but some studies have shown that earlier measurements reflect steady-state values in persons who have not bled recently. This study was aimed at assessing the changes over time in hemoglobin concentration after transfusion in acutely anemic patients because of recent bleeding. STUDY DESIGN AND METHODS: Thirty-two normovolemic patients recovering from an acute bleeding episode who were no longer thought to be bleeding and who received a 2- unit red cell transfusion were studied. At baseline and 15, 30, 60, and 120 minutes and 24 hours after transfusion, hemoglobin concentration and hematocrit values were measured. RESULTS: The administration of 2 units of packed red cells elicited a 24-hour increase of 22.4 +/− 6.8 g per L in hemoglobin concentration. Hemoglobin values were not different at any of the defined posttransfusion times. Hematocrit levels experienced similar changes over time. Agreement between 15-minute and 24-hour values was excellent, as only 6 percent of patients exhibited a clinically significant difference (> 6 g/L) between the hemoglobin measurements. CONCLUSION: Hemoglobin and hematocrit values rapidly equilibrate after transfusion in normovolemic patients who are recovering from an acute bleeding episode. This fact would allow a rapid assessment of the effects of transfusion and of the recurrence of bleeding in patients remaining at risk. 相似文献