全文获取类型
收费全文 | 20315篇 |
免费 | 1322篇 |
国内免费 | 320篇 |
专业分类
耳鼻咽喉 | 381篇 |
儿科学 | 293篇 |
妇产科学 | 299篇 |
基础医学 | 3217篇 |
口腔科学 | 297篇 |
临床医学 | 1676篇 |
内科学 | 4140篇 |
皮肤病学 | 997篇 |
神经病学 | 1420篇 |
特种医学 | 1305篇 |
外科学 | 2427篇 |
综合类 | 180篇 |
一般理论 | 5篇 |
预防医学 | 782篇 |
眼科学 | 487篇 |
药学 | 1946篇 |
中国医学 | 328篇 |
肿瘤学 | 1777篇 |
出版年
2023年 | 168篇 |
2022年 | 562篇 |
2021年 | 773篇 |
2020年 | 447篇 |
2019年 | 601篇 |
2018年 | 667篇 |
2017年 | 565篇 |
2016年 | 866篇 |
2015年 | 1188篇 |
2014年 | 1336篇 |
2013年 | 1477篇 |
2012年 | 2000篇 |
2011年 | 1814篇 |
2010年 | 1267篇 |
2009年 | 998篇 |
2008年 | 1052篇 |
2007年 | 1019篇 |
2006年 | 914篇 |
2005年 | 776篇 |
2004年 | 550篇 |
2003年 | 473篇 |
2002年 | 437篇 |
2001年 | 116篇 |
2000年 | 80篇 |
1999年 | 100篇 |
1998年 | 113篇 |
1997年 | 138篇 |
1996年 | 135篇 |
1995年 | 97篇 |
1994年 | 78篇 |
1993年 | 81篇 |
1992年 | 67篇 |
1991年 | 58篇 |
1990年 | 62篇 |
1989年 | 41篇 |
1988年 | 50篇 |
1987年 | 46篇 |
1986年 | 35篇 |
1984年 | 28篇 |
1983年 | 24篇 |
1982年 | 21篇 |
1981年 | 20篇 |
1978年 | 28篇 |
1959年 | 23篇 |
1958年 | 63篇 |
1957年 | 61篇 |
1956年 | 59篇 |
1955年 | 52篇 |
1954年 | 43篇 |
1949年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
82.
83.
Thuong PT Lee CH Dao TT Nguyen PH Kim WG Lee SJ Oh WK 《Journal of natural products》2008,71(10):1775-1778
Phytochemical study on a methanol-soluble extract of the leaves of persimmon (Diospyros kaki) resulted in the isolation of two new ursane-type triterpenoids, 3alpha,19alpha-dihydroxyurs-12,20(30)-dien-24,28-dioic acid (1) and 3alpha,19alpha-dihydroxyurs-12-en-24,28-dioic acid (2), together with 12 known ursane- and oleanane-type triterpenoids (3-14). Triterpenoids with a 3beta-hydroxy group were found to inhibit protein tyrosine phosphatase 1B (PTP1B) activity, with IC50 values ranging from 3.1+/-0.2 to 18.8+/-1.3 microM, whereas those with a 3alpha-hydroxy moiety were not active. 相似文献
84.
Kang JH Farina A Park JH Kim SH Kim JY Rizzo N Elmakky A Jun HS Hahn WB Cha DH 《Prenatal diagnosis》2008,28(8):704-709
OBJECTIVES: To estimate the combined screening performance of first and early second trimester prenatal serum markers for Down syndrome, in screening for the development of preeclampsia, and analyze the correlation among marker levels, week of onset, and severity of the disease. METHODS: A retrospective cohort study was carried out on 32 women with preeclampsia and 3044 controls. Serum samples from these pregnancies were assayed for pregnancy-associated plasma protein-A (PAPP-A), alpha-fetoprotein (AFP), unconjugated estriol (uE3), human chorionic gonadotrophin (hCG), and inhibin-A. A likelihood ratio and the odds of being affected given a positive result (OAPR) of various combinations of markers were calculated and receiver operating characteristic (ROC) curves analysis was performed. RESULTS: In the pregnancies that subsequently developed preeclampsia, first trimester PAPP-A concentration was significantly lower and concentrations of early second trimester inhibin-A and hCG significantly elevated. Levels of early second trimester uE3 and AFP were not significantly altered. We also found that inhibin-A correlates with both onset of the disease and the severity. CONCLUSION: Down syndrome biochemical markers levels are altered in those patients who subsequently developed preeclampsia and may be a useful screening test for preeclampsia. Inhibin-A is the most predictive marker and correlates with the severity of subsequent preeclampsia and inversely with the week of occurrence of preeclampsia. 相似文献
85.
86.
87.
Chung HH Jo H Kang WJ Kim JW Park NH Song YS Chung JK Kang SB Lee HP 《Gynecologic oncology》2007,104(3):529-534
OBJECTIVES: To assess the value and clinical impact of integrated PET/CT using (18)F-FDG in the diagnosis and management of women with suspected cervical cancer recurrence. METHODS: Fifty-two patients with cervical cancer with suspected recurrence because of clinical, cytological, biochemical and radiological findings were retrospectively evaluated. A final diagnosis of recurrence was confirmed by histologic tissue biopsy or by further clinical or radiological evidence. The clinical impact of information provided by PET/CT on patient management was assessed on the basis of clinical follow-up data concerning further diagnostic or therapeutic approach. RESULTS: Twenty-eight of 32 positive PET/CT scans (87.5%) were proven to have recurrent disease. Seventeen of 20 negative PET/CT scans (85.0%) had no evidence of disease. The sensitivity, specificity, and accuracy of PET/CT for detecting recurrence were 90.3%, 81.0%, and 86.5% respectively. PET/CT changed the management of 12 patients (23.1%) by changing treatment plan (5 patients), by initiating unplanned treatment strategy (4 patients), or by obviating the need for planned diagnostic procedures (3 patients). Median duration after performing PET/CT and last follow-up was 12 (range: 6-27) months, and the 2-year disease-free survival rate of patients with negative PET/CT scan for recurrence was significantly better than that of patients with positive PET/CT (85.0% vs. 10.9%, P=0002). CONCLUSIONS: In patients with a suspected recurrence of cervical cancer, integrated PET/CT using (18)F-FDG provides good anatomic and functional localization of suspicious lesions, and the better diagnostic interpretation has an impact not only on clinical management and treatment planning of patients, but also on disease-free survival. 相似文献
88.
89.
90.