全文获取类型
收费全文 | 79899篇 |
免费 | 6208篇 |
国内免费 | 293篇 |
专业分类
耳鼻咽喉 | 705篇 |
儿科学 | 3151篇 |
妇产科学 | 2159篇 |
基础医学 | 10036篇 |
口腔科学 | 1128篇 |
临床医学 | 9544篇 |
内科学 | 15747篇 |
皮肤病学 | 1302篇 |
神经病学 | 7218篇 |
特种医学 | 2022篇 |
外国民族医学 | 38篇 |
外科学 | 9344篇 |
综合类 | 1313篇 |
一般理论 | 113篇 |
预防医学 | 9189篇 |
眼科学 | 1967篇 |
药学 | 4914篇 |
1篇 | |
中国医学 | 216篇 |
肿瘤学 | 6293篇 |
出版年
2023年 | 704篇 |
2022年 | 1056篇 |
2021年 | 2250篇 |
2020年 | 1387篇 |
2019年 | 2129篇 |
2018年 | 2474篇 |
2017年 | 1784篇 |
2016年 | 1946篇 |
2015年 | 2108篇 |
2014年 | 2930篇 |
2013年 | 3995篇 |
2012年 | 5919篇 |
2011年 | 6082篇 |
2010年 | 3321篇 |
2009年 | 2883篇 |
2008年 | 5162篇 |
2007年 | 5080篇 |
2006年 | 4687篇 |
2005年 | 4551篇 |
2004年 | 4263篇 |
2003年 | 3798篇 |
2002年 | 3496篇 |
2001年 | 1431篇 |
2000年 | 1216篇 |
1999年 | 1184篇 |
1998年 | 761篇 |
1997年 | 578篇 |
1996年 | 503篇 |
1995年 | 513篇 |
1994年 | 444篇 |
1993年 | 391篇 |
1992年 | 644篇 |
1991年 | 615篇 |
1990年 | 556篇 |
1989年 | 503篇 |
1988年 | 470篇 |
1987年 | 412篇 |
1986年 | 428篇 |
1985年 | 430篇 |
1984年 | 337篇 |
1983年 | 308篇 |
1982年 | 261篇 |
1981年 | 263篇 |
1980年 | 216篇 |
1979年 | 225篇 |
1978年 | 150篇 |
1977年 | 163篇 |
1976年 | 128篇 |
1974年 | 140篇 |
1973年 | 113篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
5.
S F Wong A Lee-Tannock D Amaraddio F Y Chan H D McIntyre 《Ultrasound in obstetrics & gynecology》2006,28(7):934-938
OBJECTIVE: To assess the effect of glucose control on the rate of growth of fetuses in women with pregestational diabetes mellitus (Types 1 and 2). METHODS: All pregestational diabetic women booked at Mater Mothers' Hospital, Brisbane, Australia, between 1 January 1994 and 31 December 2002, were included. Pregnancies with congenital fetal anomalies, multiple pregnancies, and pregnancies terminated prior to 20 weeks' gestation were excluded. Dating scans were performed before 14 weeks' gestation and serial scans were performed at 18, 24, 28, 32 and 36 weeks. Fetal parameters, including biparietal diameter, femur length and abdominal circumference, were recorded. The daily growth rates for biparietal diameter, femur length, and fetal abdominal area were calculated and compared with those in a low-risk (non-diabetic) population. The growth rates in fetuses of women with satisfactory diabetic control (HbA1c < 6.5%) and unsatisfactory control (HbA1c > or = 6.5%) in the three trimesters were compared. RESULTS: A total of 174 diabetic pregnancies were included and a total of 997 ultrasound scans were performed. The growth rates for fetuses of mothers with diabetes mellitus were significantly higher than for those in the low-risk population. The z-scores for biparietal diameter, femur length, and fetal abdominal area were 0.18, 0.59 and 1.44, respectively. Fetuses of diabetic mothers with high HbA1c in the first trimester had significantly greater fetal abdominal area growth rate than those with normal HbA1c (fetal abdominal area z-score of 1.7 vs. 0.75, P = 0.009). Although the fetal abdominal area z-scores in fetuses of diabetic mothers with high HbA1c in the second or third trimesters were also higher than those with normal HbA1c levels, the differences did not reach statistical significance. Maternal obesity did not influence the fetal growth rate. CONCLUSION: The rate of growth of fetuses of diabetic mothers differs from that of the normal population. Growth acceleration persists until the late third trimester. Moreover, periconceptional glucose control appears to have a significant effect on accelerated growth of the fetal abdominal area. 相似文献
6.
Elizabeth C Frenzel Georgia A Thomas Hend A Hanna 《Infection control and hospital epidemiology》2006,27(5):512-514
At the time of hire, 4059 of 6522 healthcare workers required a 2-step tuberculin skin test; 114 workers (2.8%) demonstrated a boosted reaction after the second step. Boosted reactions were significantly associated with male sex and older age. A verbal history of previous tuberculin skin test results was not a reliable indicator of baseline tuberculin skin test status at the time of hire. 相似文献
7.
8.
Juin Fok-Seang Linda C. Smith-Thomas Sally Meiners Elizabeth Muir Jian-Sheng Du Elizabeth Housden Alan R. Johnson Andreas Faissner Herbert M. Geller Roger J. Keynes John H. Rogers James W. Fawcett 《Brain research》1995,689(2):207
The adult mammalian central nervous system (CNS) lacks the capacity to support axonal regeneration. There is increasing evidence to suggest that astrocytes, the major glial population in the CNS, may possess both axon-growth promoting and axon-growth inhibitory properties and the latter may contribute to the poor regenerative capacity of the CNS. In order to examine the molecular differences between axon-growth permissive and axon-growth inhibitory astrocytes, a panel of astrocyte cell lines exhibiting a range of axon-growth promoting properties was generated and analysed. No clear correlation was found between the axon-growth promoting properties of these astrocyte cell lines with: (i) the expression of known neurite-outgrowth promoting molecules such as laminin, fibronectin andN-cadherin; (ii) the expression of known inhibitory molecules such tenascin and chondroitin sulphate proteoglycan; (iii) plasminogen activator and plasminogen activator inhibitor activity; and (iv) growth cone collapsing activity. EM studies on aggregates formed from astrocyte cell lines, however, revealed the presence of an abundance of extracellular matrix material associated with the more inhibitory astrocyte cell lines. When matrix deposited by astrocyte cell lines was assessed for axon-growth promoting activity, matrix from permissive lines was found to be a good substrate, whereas matrix from the inhibitory astrocyte lines was a poor substrate for neuritic growth. Our findings, taken together, suggest that the functional differences between the permissive and the inhibitory astrocyte cell lines reside largely with the ECM. 相似文献
9.
Intracranial venous thrombosis has been described in newborns, but there have been no reports of intractable neonatal seizures due to this condition. We report cortical venous sinus thrombosis in two term neonates who presented with seizures in the first 24 hours of life. The diagnosis was made by cranial computed tomography and was confirmed by cerebral angiography. Both patients improved clinically after the intracranial venous thrombosis resolved. These patients demonstrate that intracranial venous thrombosis should be considered in the differential diagnosis of neonatal seizures. 相似文献
10.
Patients at Boston's Children's Hospital diagnosed as having cerebral palsy were filmed walking. These films were digitized and translated into measurements associated with leg motion. In this paper we use the gait measurements of 128 such patients to illustrate that the kth nearest neighbour clustering procedure results in a gait typology for patients with cerebral palsy. The procedure identifies four subpopulations from the sample data; the membership of a patient within this typology is mostly determined by the patient's motor control. The developed typology differs from the present diagnostic system which classifies a cerebral palsy patient as either quadriplegic, diaplegic or hemiplegic. 相似文献