全文获取类型
收费全文 | 2405篇 |
免费 | 217篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 82篇 |
妇产科学 | 64篇 |
基础医学 | 323篇 |
口腔科学 | 43篇 |
临床医学 | 217篇 |
内科学 | 606篇 |
皮肤病学 | 76篇 |
神经病学 | 222篇 |
特种医学 | 58篇 |
外科学 | 312篇 |
综合类 | 42篇 |
预防医学 | 228篇 |
眼科学 | 15篇 |
药学 | 174篇 |
中国医学 | 3篇 |
肿瘤学 | 145篇 |
出版年
2023年 | 16篇 |
2022年 | 27篇 |
2021年 | 53篇 |
2020年 | 37篇 |
2019年 | 63篇 |
2018年 | 68篇 |
2017年 | 49篇 |
2016年 | 58篇 |
2015年 | 54篇 |
2014年 | 66篇 |
2013年 | 87篇 |
2012年 | 158篇 |
2011年 | 145篇 |
2010年 | 94篇 |
2009年 | 80篇 |
2008年 | 135篇 |
2007年 | 134篇 |
2006年 | 102篇 |
2005年 | 92篇 |
2004年 | 92篇 |
2003年 | 90篇 |
2002年 | 85篇 |
2001年 | 53篇 |
2000年 | 49篇 |
1999年 | 44篇 |
1998年 | 24篇 |
1997年 | 20篇 |
1996年 | 17篇 |
1995年 | 21篇 |
1994年 | 22篇 |
1992年 | 42篇 |
1991年 | 39篇 |
1990年 | 34篇 |
1989年 | 30篇 |
1988年 | 19篇 |
1987年 | 31篇 |
1986年 | 36篇 |
1985年 | 31篇 |
1984年 | 20篇 |
1983年 | 33篇 |
1982年 | 20篇 |
1981年 | 17篇 |
1980年 | 20篇 |
1979年 | 26篇 |
1978年 | 16篇 |
1976年 | 14篇 |
1975年 | 14篇 |
1973年 | 18篇 |
1971年 | 16篇 |
1970年 | 16篇 |
排序方式: 共有2624条查询结果,搜索用时 15 毫秒
1.
2.
3.
Early responses to chemotherapy of normal and malignant hematologic cells are prognostic in children with acute lymphoblastic leukemia. 总被引:2,自引:0,他引:2
Stephen J Laughton Lesley J Ashton Edward Kwan Murray D Norris Michelle Haber Glenn M Marshall 《Journal of clinical oncology》2005,23(10):2264-2271
PURPOSE: Improved cure rates for children with acute lymphoblastic leukemia (ALL) have resulted from better relapse prediction, using clinical and laboratory features at diagnosis, and more intensive therapy in high-risk patients. More recently, measurements of the variation in the response of malignant lymphoblasts to chemotherapy in vivo have further improved relapse prediction. It is unknown whether the variation in the response of nonmalignant hematologic cells after chemotherapy correlates with the response of lymphoblasts or risk of relapse. PATIENTS AND METHODS: We retrospectively evaluated myelosuppression during induction and consolidation chemotherapy in 227 children uniformly treated for ALL on consecutive Australian and New Zealand Children's Cancer Study Group protocols. The early response to treatment was assessed in a representative subset (n = 62) by determining minimal residual disease (MRD) level by molecular techniques on the end-of-induction bone marrow sample. RESULTS: We found that a slow rate of myeloid recovery at the end of induction chemotherapy, reflected in a low absolute neutrophil count (ANC), was highly predictive of relapse (P < .0001). Additionally, patients with a high end-of-induction MRD level had a high risk of relapse (P = .001). Multivariate analysis confirmed the independent prognostic significance of MRD and ANC at the end of induction chemotherapy (P < .05). There was no significant association between other measures of myelotoxicity and MRD or relapse. CONCLUSION: We conclude that the responses of normal myeloid cells and malignant lymphoblasts to chemotherapy predict outcome by distinct mechanisms. While these results are promising, their use in the clinical setting needs to be examined in a future randomized controlled trial. 相似文献
4.
5.
Hillary R Bogner Mark S Cary Martha L Bruce Charles F Reynolds Benoit Mulsant Thomas Ten Have George S Alexopoulos 《The American journal of geriatric psychiatry》2005,13(10):861-868
OBJECTIVE: The authors described the influence of specific medical conditions on clinical remission and response of major depression (MDD) in a clinical trial evaluating a care-management intervention among older primary-care patients. METHODS: Adults age 60 years and older were randomly selected and screened for depression. Participants were randomly assigned to Usual Care or to an Intervention with a depression care-manager offering algorithm-based care for MDD. In all, 324 adults meeting criteria for MDD were included in these analyses. Remission and response was defined by a score on the Hamilton Rating Scale for Depression <10 and by a decrease from baseline of > or =50%, respectively. Medical comorbidity was ascertained through self-report. Cognitive impairment was defined by a score <24 on the Mini-Mental State Exam (MMSE). RESULTS: In Usual Care, rates of remission were faster in persons who reported atrial fibrillation (AF) than in persons who did not report AF and slower in persons who reported chronic pulmonary disease than in persons who did not report chronic pulmonary disease; rates of response were less stable in persons with MMSE <24 than in those with MMSE > or =24. In the Intervention condition, none of the specific chronic medical conditions were significantly associated with outcomes for MDD. CONCLUSIONS: Because disease-specific findings were observed in persons who received Usual Care but not in persons who received more intensive treatment in the Intervention condition, our results suggest that the association of medical comorbidity and treatment outcomes for MDD may be determined by the intensity of treatment for depression. 相似文献
6.
Ramona A. Cole Anita Bansal Debra M. Moriarity William A. Haber William N. Setzer 《Journal of natural medicines》2007,61(4):414-417
The leaf essential oil of Eugenia zuchowskiae from Monteverde, Costa Rica, has been obtained by hydrodistillation and analyzed by GC–MS. The principal constituents of
E. zuchowskiae leaf oil were α-pinene (28.3%), β-caryophyllene (13.2%), α-humulene (13.1%), and α-copaene (8.1%). The leaf essential oil
of E. zuchowskiae showed pronounced in-vitro cytotoxic activity against MCF-7, MDA-MB-468, and UACC-257 human tumor cell lines. The major components
showed cytotoxic activities comparable to doxorubicin (LC50 14–70 μg/ml). 相似文献
7.
8.
Colonic wall thickness measured by ultrasound: striking differences in patients with cystic fibrosis versus healthy controls.
下载免费PDF全文
![点击此处可从《Gut》网站下载免费的PDF全文](/ch/ext_images/free.gif)
BACKGROUND: Colonic strictures represent an advanced stage of fibrosing colonopathy in patients with cystic fibrosis. AIMS: To clarify whether ultrasonography can identify patients with an early stage of fibrosing colonopathy and to determine clinical factors that influence bowel wall thickening. PATIENTS: Ninety patients with cystic fibrosis, median age 10 years, and 46 healthy controls, median age 13 years, were investigated. METHODS: Bowel wall thickness was measured by ultrasound in a prospective study. RESULTS: In cystic fibrosis, wall thickness of both small intestine and colon was significantly (p < 0.0001) higher than in controls; 81% of patients with cystic fibrosis had a maximum colon wall thickness at any site of 2 mm or more, a value that was never reached by controls. The maximum colon wall thickness was 6.5 mm. Bowel wall thickness was unchanged at re-examination after one year. There was no progression even with high dose pancreatic supplements. There was no association between bowel wall thickness and clinical features such as previous meconium ileus, intestinal resection, distal intestinal obstruction syndrome, abdominal pain, or pancreatic enzyme dose. CONCLUSIONS: There is genuine intestinal involvement in cystic fibrosis; in a few cases this could lead to fibrosing colonopathy. 相似文献
9.
Pseudomembranous tracheobronchitis caused by Aspergillus 总被引:1,自引:0,他引:1
D W Hines M H Haber L Yaremko C Britton R W McLawhon A A Harris 《The American review of respiratory disease》1991,143(6):1408-1411
Four immunosuppressed patients with a rapidly evolving, febrile, respiratory distress syndrome were found at autopsy to have Aspergillus pseudomembranes of their lower tracheobronchial tree. Steroids, neutropenia, broad spectrum antibiotic use, and alcoholism appear to be predisposing risk factors. Bronchoscopy may reveal the pathology but antemortem diagnosis is difficult because of the low yield of sputum cultures and fulminant nature of the disease. 相似文献
10.
Jesse S Siffledeen Kerry Siminoski Hillary Steinhart Gordon Greenberg Richard N Fedorak 《Journal canadien de gastroenterologie》2003,17(8):473-478
BACKGROUND: Vitamin D deficiency is a putative, pathogenic cofactor in the increase in osteopenia and osteoporosis seen in patients with Crohn's disease. OBJECTIVE: To determine the frequency of low serum 25-hydroxy-vitamin D3 (25-OHD) levels and the associated alterations in bone mineral density in a cohort of adults with Crohn's disease. METHODS: 25-OHD levels were determined in 242 consecutive patients with Crohn's disease seen in two tertiary inflammatory bowel disease referral centres. Bone mineral density was assessed by dual energy x-ray absorptiometry. RESULTS: Nineteen (8%) patients exhibited vitamin D deficiency (25-OHD less than 25 nmol/L) and 52 (22%) patients exhibited vitamin D insufficiency (25-OHD less than 40 nmol/L). Mean T-scores at the lumbar spine, femoral neck, total hip and ultradistal radius in the group with low 25-OHD did not differ from those of the normal 25-OHD group. Serum alkaline phosphatase and parathyroid hormone levels were higher in the low 25-OHD group than in the normal group. Decreased red blood cell (RBC) folate predicted low 25-OHD in male patients, while smoking, RBC folate and serum iron predicted low 25-OHD in female patients. The rate of low 25-OHD deficiency in the winter was significantly higher than that in the summer (11.9% versus 2.8%, respectively). CONCLUSION: Vitamin D-deficient Crohn's disease patients exhibit biochemical evidence of metabolic bone disease, without detectable differences in bone mineral density. Sunlight exposure, nutrition and smoking status were predictors of vitamin D deficiency in this patient cohort. 相似文献