全文获取类型
收费全文 | 1526篇 |
免费 | 72篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 36篇 |
儿科学 | 62篇 |
妇产科学 | 86篇 |
基础医学 | 162篇 |
口腔科学 | 6篇 |
临床医学 | 145篇 |
内科学 | 331篇 |
皮肤病学 | 28篇 |
神经病学 | 111篇 |
特种医学 | 55篇 |
外科学 | 225篇 |
综合类 | 9篇 |
一般理论 | 1篇 |
预防医学 | 53篇 |
眼科学 | 29篇 |
药学 | 127篇 |
中国医学 | 9篇 |
肿瘤学 | 128篇 |
出版年
2024年 | 3篇 |
2023年 | 10篇 |
2022年 | 13篇 |
2021年 | 32篇 |
2020年 | 19篇 |
2019年 | 32篇 |
2018年 | 34篇 |
2017年 | 32篇 |
2016年 | 41篇 |
2015年 | 35篇 |
2014年 | 46篇 |
2013年 | 64篇 |
2012年 | 82篇 |
2011年 | 99篇 |
2010年 | 58篇 |
2009年 | 49篇 |
2008年 | 92篇 |
2007年 | 95篇 |
2006年 | 89篇 |
2005年 | 81篇 |
2004年 | 94篇 |
2003年 | 73篇 |
2002年 | 62篇 |
2001年 | 40篇 |
2000年 | 43篇 |
1999年 | 39篇 |
1998年 | 14篇 |
1997年 | 9篇 |
1996年 | 13篇 |
1995年 | 15篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 16篇 |
1991年 | 23篇 |
1990年 | 21篇 |
1989年 | 11篇 |
1988年 | 17篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1985年 | 9篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1974年 | 4篇 |
1910年 | 4篇 |
1909年 | 2篇 |
1908年 | 8篇 |
排序方式: 共有1603条查询结果,搜索用时 9 毫秒
11.
Celleno D Capogna G Costantino P Zangrillo A 《International Journal of Obstetric Anesthesia》1995,4(1):26-29
48 primiparae received epidural analgesia in labor with 10 ml of 0.125% bupivacaine with epinephrine 1:800 000, and then were divided in 4 equal groups (n = 12) to receive one of the following: 5 ml saline (B); 100 mug of fentanyl (BF); 150 microg of clonidine (BC); 75 microg of clonidine and 50 microg of fentanyl (BCF). All the patients had satisfactory analgesia. Onset was similar in the 4 groups but the duration of analgesia was significantly prolonged by the addition of either 100 microg of fentanyl or 150 microg of clonidine (respectively 89.8 min and 92.5 min vs 62.5 min) (P < 0.0001). The addition of both clonidine (75 microg) and fentanyl (50 microg) produced a considerably prolonged analgesia (177.5 min) (P < 0.0001). No episodes of bradycardia were observed. Hypotension, reversed by i.v. ephedrine, occurred in 2 patients of BCF group and in 1 patient of BF and BC groups. Only patients receiving fentanyl had pruritus. Both fentanyl and clonidine produced sedation, but both incidence and severity were greater with the mixture. No differences in neonatal outcome assessed by Apgar scores and NACS, were observed. 相似文献
12.
Sinonasal undifferentiated carcinoma (SNUC) is a rare and highly aggressive neoplasm of the paranasal sinuses, which has recently been characterized as a distinct pathologic entity. The prognosis for patients with SNUC is poor. Early case reports describe patients with lesions that were clinically advanced at initial presentation and surgically unresectable. Survival was reported in months after treatment with chemotherapy and radiation. As more experience was gained with treatment of SNUC, it was found that aggressive, combined surgical therapy of lesions previously considered unresectable has shown increased survival. We report a case of a 38-year-old man with SNUC originating in the posterior ethmoid, extending into the anterior cranial fossa and orbit, who was treated with preoperative hyperfractionated radiation therapy, chemotherapy, and craniofacial resection. 相似文献
13.
Hemangiopericytoma (HPC) is a rare vascular tumor that can arise in any organ system, but occurs most frequently in skeletal muscle. We present a case of a primary sphenoid sinus HPC unusual for its spontaneous remission after biopsy. There have been approximately 55 cases of sinonasal HPC reported in the literature, representing less than 5% of all lesions. In general, HPC behaves aggressively, demonstrating greater than 50% local recurrence and 10% metastatic disease. Although extended surgical resection is traditionally considered the most effective therapy for all HPC, critical literature review does not support this method of treatment for HPC occurring in the paranasal sinuses and skull base. Long-term follow-up indicates that the majority of sinonasal HPC have a benign clinical course regardless of treatment. As a result, we do not recommend extended resection as the initial therapy for sinonasal HPC. Instead, a period of observation coupled with serial MRI or CT scans should be used to detect tumor progression. These indolent tumors should undergo extended resection only after progression has been confirmed. In addition to the case report, a synopsis of the reviewed literature and a summary of treatment recommendations are also presented. 相似文献
14.
Cuzzocrea S Costantino G Mazzon E De Sarro A Caputi AP 《British journal of pharmacology》1999,128(6):1241-1251
1 The therapeutic efficacy of Mn(III)tetrakis (4-benzoic acid) porphyrin (MnTBAP), a novel superoxide dismutase mimetic which scavenges peroxynitrite, was investigated in rats subjected to shock induced by peritoneal injection of zymosan. 2 Our data show that MnTBAP (given at 1, 3 and 10 mg kg-1 intraperitoneally, 1 and 6 h after zymosan injection) significantly reduce in dose dependent manner the development of peritonitis (peritoneal exudation, high nitrate/nitrite and peroxynitrite plasma levels, leukocyte infiltration and histological examination). 3 Furthermore, our data suggest that there is a reduction in the lung, small intestine and liver myeloperoxidase (MPO) activity and lipid peroxidation activity from MnTBAP-treated rats. 4 MnTBAP also reduced the appearance of nitrotyrosine immunoreactivity in the inflamed tissues. 5 Furthermore, a significant reduction of suppression of mitochondrial respiration, DNA strand breakage and reduction of cellular levels of NAD+ was observed in ex vivo macrophages harvested from the peritoneal cavity of zymosan-treated rat. 6 In vivo treatment with MnTBAP significantly reduced in a dose-dependent manner peroxynitrite formation and prevented the appearance of DNA damage, the decrease in mitochondrial respiration and the loss of cellular levels of NAD+. 7 In conclusion our results showed that MnTBAP was effective in preventing the development of zymosan-induced shock. 相似文献
15.
Vacca A Ribatti D Gasparini G Fanelli M Minischetti M Ritelli G Costantino F Iurlaro M Bonoldi E Dammacco F 《International journal of oncology》1996,8(3):561-566
We evaluated the microvessel area (an index of angiogenesis) by using the factor VIII-related antigen (factor VIII-RA), and the expression of three components of the subendothelial basement membrane, namely: tenascin, laminin and type IV collagen. The four markers were assessed by immunohistochemical methods in 57 B-cell non-Hodgkin's lymphomas (B-NHL) and 28 benign lymphadenopathies. We found that microvessel area and the basement membrane markers had a different distribution pattern in relation to the histological type and degree of malignancy. In reactive and atypical lymphoid hyperplasias and in follicular low- and intermediate-grade B-NHL, microvessels were distributed within the interfollicular zones. By contrast, diffuse intermediate-grade and high-grade B-NHL were highly vascularized and microvessels were closely related to the neoplastic cells. Microvessel area was significantly associated with tenascin expression in all histological grades. Conversely, it was not correlated to laminin and type IV collagen expression, especially in diffuse intermediate-grade and high-grade B-NHL, where the expression of these markers was poor and fragmented. Our study suggests that angiogenesis and tenascin expression are associated phenomena in B-NHL, and that both increase with the malignancy grade. The prognostic value of angiogenesis and tenascin in B-NHL warrants further assessment in follow-up studies. 相似文献
16.
An understanding of statistical concepts is important for biomedical researchers. Statistics and probability are the scientific basis for dealing with sources of variation inherent in most biologic processes. This paper provides an introduction to the statistical framework that is fundamental to scientific methods of inquiry. Topics covered include the role of statistics, hierarchy of evidence, reliability and bias, sample size and power, random samples and random allocation, hypothesis testing, estimation, statistical inference, and publication bias. Future papers will focus on specific statistical techniques commonly used in biomedical research. 相似文献
17.
Capogna G Celleno D Sebastiani M Muratori F Costantino P Cipriani G Passarelli F Varrassi G 《International Journal of Obstetric Anesthesia》1991,1(1):19-23
In 56 women undergoing elective caesarean section, general anaesthesia was induced with either propofol 1% or thiopentone 2.5% followed by 50% nitrous oxide in oxygen and isoflurane 0.75% until delivery. In the thiopentone group the arterial pressure rose following tracheal intubation and skin incision, while in the propofol group there was a significant tendency to hypotension immediately following induction of anaesthesia. There were differences in electroencephalogram (EEG) between the groups, while laryngoscopy, intubation and surgical stimulation had no effect on EEG pattern. Recovery after anaesthesia did not differ between groups. None of the patients had recall of the intraoperative period, but 53% of patients induced with propofol showed signs of light anaesthesia between induction and delivery. Neonates in the propofol group had lower Apgar scores 1 min after birth than those in the thiopentone group, but these differences were no longer significant at 5 min. No differences were noted in neurobehavioural status at 1, 4 and 24 h. 相似文献
18.
Gerardo Zanetta Consultant Stefania Chiari Consultant Sonia Rota Registrar Giorgio Bratina Professor rea Maneo Registrar Valter Torri Medical Statistician Costantino Mangioni Professor 《BJOG : an international journal of obstetrics and gynaecology》1997,104(9):1030-1035
Objective To assess the results of a policy of tailored conservative surgical management for young women with stage I ovarian carcinomas.
Design Retrospective study.
Participants Ninety-nine women aged 40 years or younger who underwent either primary surgery in our department or were referred after primary surgery performed elsewhere.
Methods Of the 99 women in our study, 56 underwent fertility-sparing surgery and 43 more radical surgery. Minimal requirements for conservative management were adequate staging and complete information about the therapeutic options. Factors important in the choice of the treatment were, age, wish to preserve fertility, histologic type and grade, and the stage of the tumour.
Results Conservative treatment was conducted in 84% of nulliparous and in 33% of parous women; 62% of grade 1 tumours, 48% of grade 2, and 50% of grade 3 were treated conservatively. With a median follow up of seven years, we observed five recurrences (9%) of carcinoma in women treated conservatively and five (12%) in those treated more radically. Two women (one in each treatment arm) were saved after recurrence. Two recurrences after conservative surgery involved the residual ovary (3.6%). Two women developed borderline tumour in the contralateral ovary and both were treated by surgery.
Conclusion After adequate staging and accurate information is given to the patient, conservative treatment may be safe in some women with early ovarian cancer. The risk of recurrence in the contralateral ovary is low. Conservative surgery may be also considered in some Stage I grade 3 tumours and in some women with stage IC tumours. 相似文献
Design Retrospective study.
Participants Ninety-nine women aged 40 years or younger who underwent either primary surgery in our department or were referred after primary surgery performed elsewhere.
Methods Of the 99 women in our study, 56 underwent fertility-sparing surgery and 43 more radical surgery. Minimal requirements for conservative management were adequate staging and complete information about the therapeutic options. Factors important in the choice of the treatment were, age, wish to preserve fertility, histologic type and grade, and the stage of the tumour.
Results Conservative treatment was conducted in 84% of nulliparous and in 33% of parous women; 62% of grade 1 tumours, 48% of grade 2, and 50% of grade 3 were treated conservatively. With a median follow up of seven years, we observed five recurrences (9%) of carcinoma in women treated conservatively and five (12%) in those treated more radically. Two women (one in each treatment arm) were saved after recurrence. Two recurrences after conservative surgery involved the residual ovary (3.6%). Two women developed borderline tumour in the contralateral ovary and both were treated by surgery.
Conclusion After adequate staging and accurate information is given to the patient, conservative treatment may be safe in some women with early ovarian cancer. The risk of recurrence in the contralateral ovary is low. Conservative surgery may be also considered in some Stage I grade 3 tumours and in some women with stage IC tumours. 相似文献
19.
Enrico Zecca Daniele de Luca Simonetta Costa Marco Marras Pierluigi de Turris Costantino Romagnoli 《The journal of maternal-fetal & neonatal medicine》2006,19(9):569-574
OBJECTIVE: To investigate the effect of different delivery room strategies on survival, short term morbidity, and outcomes in extremely premature infants. METHODS: This retrospective cohort study included all preterm infants with a gestational age between 24 and 28 weeks who were born in 1992-1997 (period A; n = 161) and in 1998-2003 (period B; n = 163). In period A, elective intubation was performed. In period B, if spontaneous breathing was present, nasal continuous positive airway pressure (nCPAP) was applied. RESULTS: Survival rate and the number of never-intubated infants significantly increased in period B. No differences were found concerning short-term morbidity. Among major outcomes, the need for retinopathy of prematurity (ROP) surgery and the length of stay were significantly lower in period B. Subgroup analysis showed no significant differences from period A to period B in infants with gestational age 24-26 weeks. In the 27-28 weeks subgroup, the never-intubated infants rate increased from 2.8% to 21.3% and survival rate increased from 63% to 79%. A reduced need for ROP surgery and a shorter hospital stay were also observed. CONCLUSIONS: Changes in delivery room strategy tending to reduce mechanical ventilation in extremely premature infants are likely to benefit essentially infants of 27-28 weeks of gestation. Extension of such benefits to premature infants at the limit of viability requires further research. 相似文献
20.
Two families of unique glycolipids, clathrosides A-C (2a-4a) and isoclathrosides A-C (5a-7a) were isolated from the Caribbean sponge Agelas clathrodes. Clathrosides and isoclathrosides are glycosides of a very-long-chain alcohol derived from fatty acids, a new class of glycolipids that appears to be characteristic of marine sponges. The six compounds differ in configuration and in the branching of alkyl chains. Stereostructures of the clathrosides were determined by NMR and CD spectroscopy, mass spectrometry, and chemical degradation. Location of the methyl branch on the proper alkyl chain required an exceptional 1-D TOCSY experiment, in which coherence was transferred through as many as 13 vicinal couplings. 相似文献