全文获取类型
收费全文 | 558篇 |
免费 | 41篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 21篇 |
妇产科学 | 10篇 |
基础医学 | 49篇 |
口腔科学 | 44篇 |
临床医学 | 53篇 |
内科学 | 101篇 |
皮肤病学 | 16篇 |
神经病学 | 9篇 |
特种医学 | 115篇 |
外科学 | 59篇 |
综合类 | 28篇 |
预防医学 | 37篇 |
眼科学 | 7篇 |
药学 | 35篇 |
中国医学 | 1篇 |
肿瘤学 | 28篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 15篇 |
2017年 | 10篇 |
2016年 | 17篇 |
2015年 | 11篇 |
2014年 | 8篇 |
2013年 | 16篇 |
2012年 | 16篇 |
2011年 | 24篇 |
2010年 | 18篇 |
2009年 | 32篇 |
2008年 | 12篇 |
2007年 | 33篇 |
2006年 | 4篇 |
2005年 | 7篇 |
2004年 | 11篇 |
2003年 | 6篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 21篇 |
1997年 | 37篇 |
1996年 | 32篇 |
1995年 | 18篇 |
1994年 | 16篇 |
1993年 | 19篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 18篇 |
1988年 | 21篇 |
1987年 | 13篇 |
1986年 | 14篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1968年 | 3篇 |
1967年 | 6篇 |
1961年 | 2篇 |
1939年 | 5篇 |
排序方式: 共有616条查询结果,搜索用时 15 毫秒
131.
TA Griffin RW Hostoffer K-Y Tserng DJ Lebovitz CL Hoppel JL Mosser D Kaplan DS Kerr 《Acta paediatrica (Oslo, Norway : 1992)》1996,85(7):875-878
The mechanisms of hypocalcemia, recurrent infections and hypogammaglobulinemia associated with metabolic decompensation of propionic acidemia due to propionyl-CoA carboxylase deficiency have not been defined. A 7-week-old infant with this disorder presented with severe hypocalcemia and B cell lymphopenia during an episode of metabolic acidosis and hyperammonemia. Hypocalcemia (1.1 mmoll 1 ) was associated with elevated serum intact parathyroid hormone (122 ng 1 1 ), hyperphosphatemia, hypophosphaturia and hypercalcuria, indicating parathyroid hormone resistance. B cell lymphopenia (20 cells μl-1 ) was associated with transient neutropenia, anemia and subsequent hypogammaglobulinemia (IgG < 294mgdl-1 , IgM < 8mgdl-1 , IgA < 8mgdl 1 ), while T cells were normal. Parathyroid hormone resistance and B cell lymphopenia resolved following treatment with hemodialysis, diet and carnitine. These complications may be due to interference with parathyroid hormone renal tubular action and B cell maturation/proliferation by accumulated organic acids. 相似文献
132.
PJ Donald John DS McKean Boisvert M.D. Ph.D. John Tulip Judy Cummins Man-Kai Cheng 《Journal of neuro-oncology》1985,3(2):113-118
Summary Brain and glioma tissue levels of tritiated hematoporphyrin derivative (3H-HPD) were measured in normal and 9L intracerebral glioma-bearing rats at 24 hours following administration of3H-HPD 2–20 mg/kg and at 24–120 hours after3H-HPD 10 mg/kg. Levels of3H-HPD in blood, liver, spleen and muscle were also measured.Tissue levels of3H-HPD increased progressively as the dose was increased. In animals given 10 mg/kg, gradual decreases in tissue levels occurred between 24 and 72 hours but thereafter remained stable. The3H-HPD level in gliomas was consistently 2–3 × greater than in brain tissue, despite changes in dosage and time interval. High levels of activity were measured in normal brain tissue at all dosage levels, and subsequent clearance of the3H-HPD from brain, glioma, and other tissues was slow; at 120 hours after administration of 10 mg/kg, approximately 50% of the 24 hour level was still present.These results indicate that although a dose- and time-independent preferential uptake of hematoporphyrin derivative occurs in intracerebral gliomas, persistent high levels may be present in the surrounding brain. The disadvantages of using hematoporphyrin derivative rather than its individual components in studies of HPD uptake and photosensitization in the brain are discussed. 相似文献
133.
Purpose: To determine if the pattern of release of neurotensin from the enkephalin-, neurotensin- and somatostatin-like immunoreactive amacrine cells in response to light and dark is the same as that of the enkephalins and somatostatin. Methods/Results: Both the enkephalins and somatostatin are released at high rates in the dark and at lower rates in the light, and these rate changes are reflected in increasing intracellular levels of the peptides in vivo in the light and decreasing levels in the dark The levels of neurotensin-like immunoreactivity show a similar diurnal light-driven and non-circadian rhythm in vivo. Conclusion: This implies that the actual release rates of neurotensin follow the same patterns as those demonstrated in vitro for the enkephalins and somatostatin. 相似文献
134.
Yuri Tolkach Heidrun Gevensleben Ralph Bundschuh Aydan Koyun Daniela Huber Christina Kehrer Thomas Hecking Mignon-Denise Keyver-Paik Christina Kaiser Hojjat Ahmadzadehfar Markus Essler Walther Kuhn Glen Kristiansen 《Breast cancer research and treatment》2018,169(3):447-455
Purpose
Prostate-specific membrane antigen (PSMA), a protein product of the folate hydrolase 1 (FOLH1) gene, is gaining increasing acceptance as a target for positron emission tomography/computer tomography (PET/CT) imaging in patients with several cancer types, including breast cancer. So far, PSMA expression in breast cancer endothelia has not been sufficiently characterized.Methods
This study comprised 315 cases of invasive carcinoma of no special type (NST) and lobular breast cancer (median follow-up time 9.0 years). PSMA expression on tumor endothelia was detected by immunohistochemistry. Further, vascular mRNA expression of the FOLH1 gene (PSMA) was investigated in a cohort of patients with invasive breast cancer provided by The Cancer Genome Atlas (TCGA).Results
Sixty percent of breast cancer cases exhibited PSMA-positive endothelia with higher expression rates in tumors of higher grade, NST subtype with Her2-positivity, and lack of hormone receptors. These findings were confirmed on mRNA expression levels. The highest PSMA rates were observed in triple-negative carcinomas (4.5 × higher than in other tumors). Further, a case of a patient with metastatic breast cancer showing PSMA expression in PET/CT imaging and undergoing PSMA radionuclide therapy is discussed in detail.Conclusions
This study provides a rationale for the further development of PSMA-targeted imaging in breast cancer, especially in triple-negative tumors.135.
Brief hospitalization contributes to quicker and more effective recovery in psychiatric practice. It also leads to a progressive change in the pattern of mental morbidity. Two-year follow-up of patients treated with this technique indicates that recovery is sustained, and relapse/wastage rate is low. There is need for further research in this significant aspect of military medicine.KEY WORDS: Follow-up studies, Hospitalization, Length of stay, Outcome assessment 相似文献
136.
137.
Prevalence and infectivity of hepatitis G virus and its strain variant, the GB agent, in volunteer blood donors in Taiwan 总被引:2,自引:0,他引:2
BACKGROUND: The prevalence of hepatitis G virus (HGV) and its strain variant, the GB agent (GBV-C) is high in non-virus-inactivated plasma products, but, persistent infection in recipients is relatively low. STUDY DESIGN AND METHODS: Stored samples from transfusion donors and recipients in a prospective study of posttransfusion hepatitis were tested for HGV RNA and antibody to the E2 protein (anti-E2). RESULTS: Thirty-two (2.1%) of the 1500 qualified donors were positive for HGV RNA. Twenty-four persons had received a transfusion of blood from one of these 32 viremic donors. Of these 24 recipients, 3 were positive for HGV RNA before transfusion. Of the remaining 21 recipients, 8 became viremic after transfusion, while the other 13 were not infected. Four of the eight infected recipients were persistently positive for HGV RNA, while four became negative in 1 to 3 years. Three of the four patients with HGV clearance seroconverted to anti-E2 positivity. Comparison of the viral titer, viral sequences at E2, storage period of blood donations, and clinical data in the infected and noninfected recipients revealed no significant differences. However, the noninfected recipients seemed to have a higher prevalence of anti-E2 before transfusion. CONCLUSION: The prevalence of HGV viremia in volunteer blood donors in Taiwan is 2.1 percent, and blood from 0.6 percent of them actually causes HGV infection in the recipients. In half of infected recipients, clearance of HGV occurs. Anti-E2 appears in most recipients whose viremia is cleared. 相似文献
138.
Beverley O’Brien RM RN PhD Beverley Chalmers DS PhD Deshayne Fell MSc Maureen Heaman RN MN PhD Elizabeth K. Darling RM MSc Pearl Herbert BN BEd MSc 《分娩》2011,38(3):207-215
Abstract: Background: In Canada maternity care is publicly funded, and although women may choose their care providers, choices may be limited. The purpose of this study was to compare perceptions of maternity outcomes and experiences of those who received care from midwives with those who received care from other providers. Methods: Based on the 2006 Canadian census, a random sample of women (n = 6,421) who had recently given birth in Canada completed a computer‐assisted telephone interview for the Maternity Experiences Survey. The sample was stratified according to province or territory where birth occurred, age, rural or urban residence, and presence of other children in the home. Those who were 15 years of age and older, gave birth to a singleton baby, and were living with their infant were eligible for inclusion. Results: Women whose primary prenatal providers were midwives had fewer ultrasounds and were more likely to attend prenatal classes and have at least five or more prenatal visits. They were also more likely to rate satisfaction with their maternity experience as “very positive” and be satisfied with information provided on a variety of pregnancy and birth topics if their primary prenatal provider was a midwife. They were almost half as likely to experience induction and 7.33 times more likely to experience a medication‐free delivery. They were more likely to initiate and maintain breastfeeding at 3 and 6 months. Conclusions: Evidence shows that midwifery outcomes and levels of satisfaction meet or exceed Canadian maternity care standards. Facilitation of the continuing integration of midwives as autonomous practitioners throughout Canada is recommended. (BIRTH 38:3 September 2011) 相似文献
139.
Doerte W. Luedders Diana Bundschuh Amadeus Hornemann Jana-Christin Hoerster Philipp Boemicke Frank Köster Michael K. Bohlmann 《Archives of gynecology and obstetrics》2011,284(2):287-292
Purpose
The prevalence of diabetic disorders in pregnancy is rising, which goes along with increased risks for maternal and foetal complications during pregnancy and delivery. The expression of the endo-β-d-glucuronidase, heparanase (HPSE), may increase under hyperglycaemic conditions, is believed to play an important role in diabetes associated morbidity outside the female reproductive tract and is expressed in the placenta throughout gestation. However, the placental expression of HPSE has not been investigated in diabetic patients. 相似文献140.