全文获取类型
收费全文 | 659861篇 |
免费 | 40590篇 |
国内免费 | 739篇 |
专业分类
耳鼻咽喉 | 9327篇 |
儿科学 | 21940篇 |
妇产科学 | 17068篇 |
基础医学 | 106715篇 |
口腔科学 | 19766篇 |
临床医学 | 56552篇 |
内科学 | 119630篇 |
皮肤病学 | 16140篇 |
神经病学 | 51092篇 |
特种医学 | 24618篇 |
外国民族医学 | 63篇 |
外科学 | 99185篇 |
综合类 | 9120篇 |
一般理论 | 156篇 |
预防医学 | 47170篇 |
眼科学 | 15272篇 |
药学 | 50468篇 |
中国医学 | 1216篇 |
肿瘤学 | 35692篇 |
出版年
2019年 | 5020篇 |
2018年 | 7916篇 |
2017年 | 6213篇 |
2016年 | 7360篇 |
2015年 | 7418篇 |
2014年 | 9323篇 |
2013年 | 15179篇 |
2012年 | 19979篇 |
2011年 | 22236篇 |
2010年 | 12903篇 |
2009年 | 11175篇 |
2008年 | 21641篇 |
2007年 | 23102篇 |
2006年 | 23094篇 |
2005年 | 22518篇 |
2004年 | 21623篇 |
2003年 | 21003篇 |
2002年 | 20736篇 |
2001年 | 29144篇 |
2000年 | 31279篇 |
1999年 | 24359篇 |
1998年 | 7062篇 |
1997年 | 6051篇 |
1996年 | 6114篇 |
1995年 | 5572篇 |
1994年 | 5211篇 |
1992年 | 16966篇 |
1991年 | 17427篇 |
1990年 | 17556篇 |
1989年 | 16951篇 |
1988年 | 15602篇 |
1987年 | 15511篇 |
1986年 | 14525篇 |
1985年 | 14037篇 |
1984年 | 10593篇 |
1983年 | 9056篇 |
1982年 | 5259篇 |
1979年 | 10143篇 |
1978年 | 7472篇 |
1977年 | 6373篇 |
1976年 | 6134篇 |
1975年 | 6969篇 |
1974年 | 8215篇 |
1973年 | 7626篇 |
1972年 | 7401篇 |
1971年 | 7130篇 |
1970年 | 6597篇 |
1969年 | 6242篇 |
1968年 | 5929篇 |
1967年 | 5387篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
T Abumiya I Sayama K Asakura H Hadeishi M Mizuno A Suzuki N Yasui F Shishido K Uemura 《No shinkei geka. Neurological surgery》1990,18(9):837-844
Regional effects of craniotomy on cerebral circulation and metabolism, such as regional cerebral blood flow (rCBF), regional cerebral oxygen consumption (rCMRO2), regional oxygen extraction fraction (rOEF), and regional cerebral blood volume (rCBV) were examined by a PET (positron emission tomography) study concerning surgery that was performed on unruptured aneurysm patients. Eight patients with intracranial un-ruptured aneurysms were studied pre- and post-operatively by the 15O labelled-gas steady-state method, using HEADTOME-III. All patients underwent aneurysmal surgery performed by the transsylvian approach. There was a significant increase in the mean OEF values taken from the whole-brains of 8 patients, but there was not a significant change in CBF, CMRO2 or CBV. The increase in OEF was caused by decrease of O2 content, which was caused by post-operative decrease in the Hb value. So, this OEF increase was not the direct effect of craniotomy. In 2 patients, the rCBF and rCMRO2, in the fronto-temporal region (where craniotomy was performed) increased post-operatively. This regional effect suggests transient reactive hyperemia following compressive ischemia during the operative procedure, and metabolic demands for recovery of brain function. In 2 other patients, who had relatively low rCBFs during the pre-operative study, rCBF and rCMRO2 in the bi-frontal region had decreased more at the post-operative study. This change appears to have been caused by removal of cerebrospinal fluid and depression of the frontal lobe. From this study, it becomes evident that the regional effect of craniotomy on cerebral circulation and metabolism is not so great, when adequate microsurgical techniques are used. 相似文献
62.
Management of splenic injuries in children has evolved over the past two decades. Splenectomies or splenorrhaphies are now performed infrequently, with the majority of hemodynamically stable children with splenic injuries managed nonoperatively. This article reviews the imaging features of acute splenic injuries in children as well as the appearance of healing splenic injuries. Follow-up evaluation and outcomes in children with splenic injuries also are addressed. 相似文献
63.
64.
65.
The response of single detergent treated bovine retinal pigment epithelial cells in culture to ATP was measured with an image analyser. The most pronounced contraction was produced by 1.0 mM ATP with most change taking place in the first 10 min. At 1 h the area had decreased by about 33%, perimeter 22% and maximum length 25%. By way of comparison rabbit skin fibroblasts had a decreased area of approximately 40%, perimeter 25% and maximum length 22%. Bovine aortic smooth muscle cells on the other hand decreased in area by 55%, perimeter 40% and maximum length 36%. It is hoped that this assay may be used to evaluate drugs which could counteract contractile events in proliferative vitreoretinopathy. 相似文献
66.
B. Bogin P. Smith A.B. Orden M.I. Varela Silva J. Loucky 《American journal of human biology》2002,14(6):753-761
Maya families from Guatemala migrated to the United States in record numbers from the late 1970s to the early 1990s. Births to Maya immigrant women have created a sizable number of Maya American children. The height and sitting height of 5 to 12 years children (n = 431) were measured in 1999 and 2000. Leg length was estimated and the sitting height ratio was calculated. These data were compared with a sample of Maya children living in Guatemala measured in 1998 (n = 1,347). Maya American children are currently 11.54 cm taller and 6.83 cm longer‐legged, on average, than Maya children living in Guatemala. Consequently, the Maya Americans have a significantly lower average sitting height ratio (i.e., relatively longer legs in proportion to length of the head and trunk) than do the Maya in Guatemala. These results add support to the hypothesis that both the height and body proportions of human populations are sensitive indicators of the quality of the environment for growth. Am. J. Hum. Biol. 14:753–761, 2002. © 2002 Wiley‐Liss, Inc. 相似文献
67.
68.
69.
70.
I A Bochkov O D Trofimova O S Darbeeva R S Cherkasskaia M S Shevchuk 《Laboratornoe delo》1989,(6):43-47
Formulae for the calculation of the count of microorganisms isolated from natural bacterial biocenoses of a child's body have been derived. The authors suggest a variant of simplified drip method for the computation of microorganism colonies in solid media. The described method helps cut down the nutrient media consumption at least 3-fold and is time-saving. 相似文献