全文获取类型
收费全文 | 8049篇 |
免费 | 647篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 81篇 |
儿科学 | 232篇 |
妇产科学 | 160篇 |
基础医学 | 973篇 |
口腔科学 | 204篇 |
临床医学 | 926篇 |
内科学 | 1778篇 |
皮肤病学 | 114篇 |
神经病学 | 426篇 |
特种医学 | 272篇 |
外科学 | 1131篇 |
综合类 | 193篇 |
一般理论 | 1篇 |
预防医学 | 519篇 |
眼科学 | 131篇 |
药学 | 645篇 |
中国医学 | 28篇 |
肿瘤学 | 930篇 |
出版年
2023年 | 45篇 |
2022年 | 86篇 |
2021年 | 169篇 |
2020年 | 98篇 |
2019年 | 154篇 |
2018年 | 195篇 |
2017年 | 126篇 |
2016年 | 157篇 |
2015年 | 170篇 |
2014年 | 245篇 |
2013年 | 333篇 |
2012年 | 490篇 |
2011年 | 495篇 |
2010年 | 280篇 |
2009年 | 242篇 |
2008年 | 443篇 |
2007年 | 499篇 |
2006年 | 456篇 |
2005年 | 432篇 |
2004年 | 385篇 |
2003年 | 375篇 |
2002年 | 330篇 |
2001年 | 295篇 |
2000年 | 256篇 |
1999年 | 204篇 |
1998年 | 93篇 |
1997年 | 67篇 |
1996年 | 72篇 |
1995年 | 55篇 |
1994年 | 49篇 |
1993年 | 52篇 |
1992年 | 144篇 |
1991年 | 112篇 |
1990年 | 132篇 |
1989年 | 115篇 |
1988年 | 103篇 |
1987年 | 92篇 |
1986年 | 81篇 |
1985年 | 73篇 |
1984年 | 54篇 |
1983年 | 57篇 |
1982年 | 36篇 |
1981年 | 35篇 |
1980年 | 26篇 |
1979年 | 49篇 |
1978年 | 31篇 |
1977年 | 26篇 |
1975年 | 25篇 |
1974年 | 34篇 |
1971年 | 22篇 |
排序方式: 共有8744条查询结果,搜索用时 15 毫秒
1.
Ngai-Yin Chan Chi-Chung Choy Ho-Chuen Yuen Hoi-Fan Chow Ho-Fai Fong 《The Canadian journal of cardiology》2019,35(4):396-404
Background
Persistent iatrogenic atrial septal defect (iASD) is a common but poorly characterized complication after cryoballoon (CB) pulmonary vein isolation (PVI) procedures. We therefore investigate its prevalence, evolution, risk factors, and clinical outcomes in a prospective longitudinal study.Methods
A total of 108 patients (41 women, mean age 57 ± 11.3) underwent CB PVI for AF. Serial transesophageal echocardiography (TEE) was performed 9 months and then annually until 6 years after the procedure to study the characteristics of persistent iASD.Results
Persistent iASD occurred in 33 (30.6%) patients 9 months after CB PVI. Spontaneous closure of iASD was found in 6 (22.2%) and 3 (15.8%) patients 2 and 3 years after the procedures, respectively. No spontaneous closure was observed on 4, 5, and 6-year TEE follow-up. The projected long-term persistence rate of iASD after CB PVI was therefore 20% (30.6% × 0.778 × 0.842). Using multivariate logistic regression, a higher number of cryoapplications (≥ 2 minutes) was the only independent predictor of persistent iASD 9 months after CB PVI (odds ratio [OR] 1.207; 95% confidence interval [CI], 1.033-1.411, P = 0.018). Two (1.9%) patients with significantly larger iASD size than the others (long diameter 12.6 ± 0.8 vs 3.7 ± 1.5 mm, P < 0.001; short diameter 10.9 ± 0.2 vs 3 ± 1.1 mm, P < 0.001) required percutaneous closure because of exertional dyspnea and right ventricular enlargement. Over 129.7 patient-years follow-up, during which iASD persisted, there was no occurrence of neurologic events.Conclusions
Approximately one fifth of patients undergoing CB PVI will have permanently persistent iASD. Patients with defect sizes of greater than 10 mm may need percutaneous closure due to significant left-to-right shunting. 相似文献2.
3.
Robert K.P Chow MD Vincent C Ho MD FRCPC 《Journal of the American Academy of Dermatology》1996,34(6):1047-1060
Critical to the proper management of pyoderma gangrenosum are correct diagnosis, identification and treatment of any underlying disorder, and the proper choice of topical and systemic therapy. Many agents are available for the treatment of pyoderma gangrenosum. We review the current therapeutic options, their efficacy and side effects, and we offer some guidelines for their proper selection. 相似文献
4.
N. H. Chow Y. L. Guo J. S. Lin J. H. Su T. S. Tzai H. R. Guo I. J. Su 《British journal of cancer》1997,75(11):1708-1710
A high incidence of bladder cancer has been documented in an area of chronic arsenic (As) exposure. This study investigates the characteristics of As-associated (n = 49) and other (n = 64) bladder cancers. A higher histological grading was observed for the As-exposed tumours (P = 0.04), but no other difference in pathobiological features or prognosis was found between the two groups. 相似文献
5.
Soft tissue sarcomas of the head and neck in adults 总被引:1,自引:0,他引:1
We reviewed the clinical records and pathologic material of 176 adults with primary soft tissue sarcomas treated at Memorial Sloan-Kettering Cancer Center between 1950 and 1985. Seventy-two patients (41%) had low-grade sarcomas and 104 (59%) had high-grade sarcomas. All but 18 patients underwent some form of excision as initial therapy. Adjuvant radiotherapy and chemotherapy combined with surgical excision showed no significant effect. A significantly increased risk of treatment failure was associated with large tumor size, positive surgical margins, bone involvement, local recurrence, metastatic spread, and high histologic grade. Except for recurrence, the p value by univariate analysis in the log-rank test for comparison of survival according to these clinical and pathologic characteristics was p less than 0.0001. Although the overall survival was 75% at 2 years, 55% at 5 years, and 46% at 10 years, only 20% of the patients with high-grade sarcomas were alive 10 years after treatment. Most patients with rhabdomyosarcoma, high-grade peripheral nerve tumor, and high-grade fibrous histiocytoma and all patients with high-grade angiosarcoma died of disease less than 5 years after diagnosis. New therapeutic strategies are needed to improve the survival of adult patients with high-grade soft tissue sarcomas of the head and neck. 相似文献
6.
7.
Benyam Asefa Paul Kauler Denis Cournoyer Shirley Lehnert T. Y.-K. Chow 《Current genetics》1998,34(5):360-367
The deoxyribonucleases (DNases) have been shown genetically to be important in the vital processes of DNA repair and recombination.
The NUD1 gene, which codes for an endo-exonuclease of Saccharomyces cerevisiae, was analyzed for its role in the DNA double-strand break (DSB) repair processes. While the nud1 strain is only slightly sensitive to ionizing radiation, expression of the HO-endonuclease to introduce a DSB at the MAT locus in that strain results in cell death. Cell survival is inversely proportional to the duration of HO-endonuclease expression.
Analysis of the surviving colonies from the nud1 strain indicated that many of the survivors are sterile and that the proportion of these sterile survivors increases with
the time of HO-endonuclease expression. On the other hand, the surviving colonies from the isogenic NUD1 strain are mating-proficient. Interestingly, double mutants of nud1 rad52 are more resistant to ionizing irradiation than the rad52 strain and have a cell-survival fraction of 32% for rad52-1 nud1 and 9% for rad52::URA3 nud1 following prolonged HO-endonuclease expression, indicating that nud1 has a suppressor effect on the DSB-induced lethality in rad52. Polymerase chain reaction analysis showed that many of the nud1 survivors contained small alterations within the MAT locus, suggesting that the survivors arose through the process of non-homologous end-joining. These results suggest that
the endo-exonuclease acts at a DSB to promote DNA repair via the homologous recombination pathway.
Received: 20 July / 20 September 1998 相似文献
8.
LY Chow MRCPsych D Chung MRCPsych V Leung MB BS TF Leung MB ChB CM Leung MRCPsych 《International journal of clinical practice》1997,51(5):330-331
Akathisia as a side-effect of metoclopramide has received increasing attention in consultation-liaison psychiatry in recent years. A case of metoclopramide-induced akathisia resulting in a suicide attempt is reported in order to highlight the suffering of such patients and the factors that lead to misdiagnosis. 相似文献
9.
10.
The survival rate and elastic properties of the anterior abdominal skin flap in Sprague-Dawley rats were studied in three groups of animals. In group 1 where the flaps were supplied by a normal artery, arterial flaps (1A) had better survival rate and elastic properties than venous flaps (1B). In group 2, where the flaps were supplied by an artery with diminished perfusion pressure, the arterial flaps (2A) still had slightly better results than venous flaps (2B). However, in group 3 where the flaps were supplied by a vein, venous flaps (3B) had better results than arterial flaps (3A). 相似文献