全文获取类型
收费全文 | 32258篇 |
免费 | 2996篇 |
国内免费 | 125篇 |
专业分类
耳鼻咽喉 | 329篇 |
儿科学 | 1061篇 |
妇产科学 | 629篇 |
基础医学 | 4546篇 |
口腔科学 | 410篇 |
临床医学 | 3878篇 |
内科学 | 7035篇 |
皮肤病学 | 761篇 |
神经病学 | 3439篇 |
特种医学 | 1035篇 |
外国民族医学 | 1篇 |
外科学 | 4683篇 |
综合类 | 239篇 |
一般理论 | 29篇 |
预防医学 | 2747篇 |
眼科学 | 392篇 |
药学 | 1881篇 |
中国医学 | 65篇 |
肿瘤学 | 2219篇 |
出版年
2023年 | 113篇 |
2022年 | 234篇 |
2021年 | 553篇 |
2020年 | 478篇 |
2019年 | 862篇 |
2018年 | 969篇 |
2017年 | 803篇 |
2016年 | 809篇 |
2015年 | 1007篇 |
2014年 | 1222篇 |
2013年 | 1708篇 |
2012年 | 1998篇 |
2011年 | 2203篇 |
2010年 | 1410篇 |
2009年 | 1299篇 |
2008年 | 1915篇 |
2007年 | 1988篇 |
2006年 | 1930篇 |
2005年 | 1991篇 |
2004年 | 1920篇 |
2003年 | 1939篇 |
2002年 | 1995篇 |
2001年 | 315篇 |
2000年 | 256篇 |
1999年 | 327篇 |
1998年 | 394篇 |
1997年 | 368篇 |
1996年 | 290篇 |
1995年 | 329篇 |
1994年 | 270篇 |
1993年 | 257篇 |
1992年 | 180篇 |
1991年 | 194篇 |
1990年 | 166篇 |
1989年 | 140篇 |
1988年 | 152篇 |
1987年 | 157篇 |
1986年 | 144篇 |
1985年 | 138篇 |
1984年 | 152篇 |
1983年 | 120篇 |
1982年 | 176篇 |
1981年 | 171篇 |
1980年 | 154篇 |
1979年 | 96篇 |
1978年 | 102篇 |
1977年 | 92篇 |
1976年 | 75篇 |
1975年 | 64篇 |
1972年 | 67篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Permanent access to the portal system for cellular transplantation using an implantable port device.
Ahmed A Darwish Etienne Sokal Xavier Stephenne Mustapha Najimi Jean de Ville de Goyet Raymond Reding 《Liver transplantation》2004,10(9):1213-1215
A novel application of the implantable Port-a-Cath (PAC) system is described in the context of cellular transplantation. A silicone catheter was inserted in a collateral branch of the portal vein and connected to a port device positioned subcutaneously on the left thoracic cage. This permanent vascular access allowed iterative intraportal infusions of allogenic hepatocytes without the need of repeated transhepatic catheterization of the portal vein. Using this technique, repeated infusions of cryopreserved and / or fresh hepatocytes were successfully carried out in 3 children with inborn errors of liver metabolism, with the aim of progressively providing a sufficient mass of transplanted liver cells to stabilize the metabolic condition of the patients. We suggest that this technique might also be valuable in pancreatic islet cell transplantation. 相似文献
102.
103.
Stéphane Aubert Roland Henaine Olivier Raisky Nicolas Chavanis Jacques Robin René Ecochard Jean Ninet 《European journal of cardio-thoracic surgery》2005,28(2):223-228
OBJECTIVE: We consider the short- and long-term outcomes of the repair of the isolated partial atrioventricular (AV) septal defect to determine the role played by the atypical forms on the initial AV valve replacement and on the risk of reoperation. METHODS: Two hundred and eight patients underwent an operation for this malformation between 1974 and 2001. Clinical and echocardiographic examinations were performed on all patients, the AV valve regurgitation was graded from 1 to 4 and a residual interatrial shunt was sought. Median age at the intervention was 5.8 years (3 months to 67 years). RESULTS: Median follow-up time was 7.5 years (range 0-22.6 years). The cumulative 30-day, 5- and 20-year survival rates were 96.5, 95.4 and 94.6%, respectively. AV valve replacement was associated with a high mortality (P<0.001). A reoperation was performed on 12 patients (5.7%) including six patients within less than a 30-day period, especially to repair residual AV valve regurgitation. We performed four AV valve repairs by annuloplasty and six AV valve replacements. Two patients who had initially undergone an AV valve replacement underwent a reoperation for valve thrombosis. The cumulative 30-day, 5- and 20-year rates of freedom from reoperation were 96.5, 93.6 and 83%, respectively. An atypical form was present in 24 patients (11.5%) and was a risk factor for initial AV valve replacement (P<0.001) and for reoperation (P<0.001). A complete AV block occurred in 13 patients (6.2%), all of them within a 30-day period. The AV valve replacement was a high risk factor for a complete AV block (P<0.001). At the end of our study 180 patients (96%) were in NYHA I and 8 in NYHA II. CONCLUSIONS: The morbi-mortality of the isolated partial AV septal defect is primarily perioperative and is linked with the presence of an atypical form of the lesion. This atypical form was the main reason for reoperation for AV valve regurgitation. The AV valve replacement was associated with a high mortality and with the occurrence of complete AV block. Using a standardized technique, the AV septal defect can be repaired with excellent long-term clinical and echographic results. 相似文献
104.
105.
Rawling Jean M.; Driscoll Eric R.; Poirier Guy G.; Kirkland James B. 《Carcinogenesis》1993,14(12):2513-2516
Poly(ADP-ribose) (polymer) is enzymatically synthesized on nuclearproteins in response to DNA strand breaks. NAD+ is the substratefor this reaction, which is catalyzed by Poly(ADP-ribose)polymerase.This post-translational modification occurs in response to DNAstrand breaks and is thought to play an important role in DNArepair. Polymer synthesis resulting from DNA damage has beendescribed in cultured cells, but measurement is more difficultin animal tissues. In this study, modifications were made toan earlier method to measure carcinogen-induced increases inpolymer levels in vivo. RNase I was added to the enzyme mixtureused to digest polymer to ribosyladenosine (RAdo). This preventedthe inhibition of snake venom phosphodiesterase by RNA. TheHPLC analysis was improved, allowing elimination of the secondboronate affinity chromatography step traditionally used topurify 相似文献
106.
Deanna Ashley Maureen Samms-Vaughan Rosemary Greenwood Jean Golding 《Paediatric and perinatal epidemiology》1994,8(S1):158-165
Summary. The Jamaican Perinatal Mortality Survey collected data that have been used in this paper to estimate: (1) the rate of multiple deliveries on the island; (2) the way in which this varies with demographic features; and (3) the causes of perinatal mortality among twins on the island.
The survey consisted of two phases: a study of all births in the months of September and October 1986 (the cohort months) and a study of all perinatal deaths in the 12 months from 1 September 1986 to 31 August 1987.
Among the 10408 pregnancies in the cohort months, 99(1.0%) were multiple pregnancies. The twinning rate showed statistically significant trends with maternal age and parity but no association with social factors.
Among the 2020 perinatal deaths occurring in the 12-month period, 173 (8.6%) were twins, with particularly high contribution to the Wigglesworth group 'deaths from immaturity'. Mortality rate of twins was significantly lower if mothers resided in areas where there were good obstetric and paediatric facilities. 相似文献
The survey consisted of two phases: a study of all births in the months of September and October 1986 (the cohort months) and a study of all perinatal deaths in the 12 months from 1 September 1986 to 31 August 1987.
Among the 10408 pregnancies in the cohort months, 99(1.0%) were multiple pregnancies. The twinning rate showed statistically significant trends with maternal age and parity but no association with social factors.
Among the 2020 perinatal deaths occurring in the 12-month period, 173 (8.6%) were twins, with particularly high contribution to the Wigglesworth group 'deaths from immaturity'. Mortality rate of twins was significantly lower if mothers resided in areas where there were good obstetric and paediatric facilities. 相似文献
107.
B n dicte Brichard Jacques Ninane Serge Gosseye Christine Verellen-Dumoulin Christiane Vermylen Jean Rodhain Guy Comu 《Pediatric hematology and oncology》1991,8(3):215-219
A 9-year-old boy presented with a small subcutaneous tumor of the trunk and diffuse bone marrow involvement. The first histological diagnosis given was undifferentiated malignancy possibly of neural crest origin and chemotherapy was started immediately using vincristine, cyclophosphamide, cisplatin, and teniposide (OPEC). Complete response was achieved after four courses of chemotherapy. Histological slides were then reviewed and the final diagnosis of alveolar rhabdomyosarcoma (RMS) was retained. Moreover, chromosome analysis of malignant cells in the bone marrow revealed a translocation involving chromosomes 2 and 13:t(2;13) (q35;q14). This specific karyotype finding has been recently reported in a few cases and could be specific for alveolar RMS. The patient had a relapse 7 months after diagnosis and died 4 months later. 相似文献
108.
109.
The CO2 laser, emitting at 10,600 nm in the extreme infrared wavelength has special advantages for ophthalmology: its hemostatic properties and its ability to cut, vaporize, and shrink tissue make it particularly effective on the external eye and adenexae. In particular, it can be used for layerwise removal of tissue on the conjunctiva, the sclera, and the lids. Energy and exposure time are especially important. Irradiation of sclera from enucleated globes showed that these two parameters have a direct effect on the depth of craters - the CO2 laser's typical impact - and the laser's thermal effect on tissue. Technical and practical observations and the clinical results of more than 80 cases treated with the CO2 laser are presented and discussed. The low-power CO2 laser is a useful ophthalmological tool which can partially replace conventional surgery and extend treatment indications. 相似文献
110.
Paula Murphy Peterson Karen Kaufmann Rauen Jean Brown Jeane Cole 《Rehabilitation nursing》1994,19(4):229-238
Many concerns surround the preparation of a person with spina bifida for a successful transition into adult life and responsibilities. A model of intervention must be based on developmental concerns and timely issues from infancy through all stages of development to young-adult life. This article discusses, within a developmental framework, issues of transition in relation to physical, social, emotional, and educational/vocational needs; it also presents a conceptual framework for the transition into adulthood. Guidelines were developed by incorporating expected outcomes of people with spina bifida and using a philosophical framework that encompasses the achievement of a balance among dependence, independence, and interdependence. This model is based on developmental issues from infancy through all stages of development to young-adult life. Using this framework for care, the rehabilitation nurse can feel confident that the needs of clients with spina bifida and similar chronic conditions are being met. 相似文献