全文获取类型
收费全文 | 1166篇 |
免费 | 80篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 42篇 |
妇产科学 | 7篇 |
基础医学 | 149篇 |
口腔科学 | 72篇 |
临床医学 | 118篇 |
内科学 | 215篇 |
皮肤病学 | 10篇 |
神经病学 | 83篇 |
特种医学 | 194篇 |
外科学 | 91篇 |
综合类 | 74篇 |
预防医学 | 60篇 |
眼科学 | 29篇 |
药学 | 46篇 |
中国医学 | 24篇 |
肿瘤学 | 26篇 |
出版年
2023年 | 6篇 |
2022年 | 8篇 |
2021年 | 17篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 26篇 |
2017年 | 19篇 |
2016年 | 21篇 |
2015年 | 15篇 |
2014年 | 40篇 |
2013年 | 65篇 |
2012年 | 56篇 |
2011年 | 50篇 |
2010年 | 55篇 |
2009年 | 46篇 |
2008年 | 50篇 |
2007年 | 63篇 |
2006年 | 33篇 |
2005年 | 19篇 |
2004年 | 19篇 |
2003年 | 15篇 |
2002年 | 16篇 |
2001年 | 16篇 |
2000年 | 16篇 |
1999年 | 28篇 |
1998年 | 61篇 |
1997年 | 54篇 |
1996年 | 42篇 |
1995年 | 32篇 |
1994年 | 35篇 |
1993年 | 28篇 |
1992年 | 10篇 |
1991年 | 14篇 |
1990年 | 17篇 |
1989年 | 25篇 |
1988年 | 29篇 |
1987年 | 26篇 |
1986年 | 17篇 |
1985年 | 29篇 |
1984年 | 14篇 |
1983年 | 14篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1980年 | 14篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 6篇 |
1969年 | 3篇 |
排序方式: 共有1251条查询结果,搜索用时 0 毫秒
61.
目的建立大鼠心肌梗死后心力衰竭模型,并进行评估,以提高存活率和成功率。方法分批对70只SD大鼠行冠状动脉左前降支结扎术,同时设15只假手术组,并计算死亡率。于4周时行血流动力学检查,检测心率(HR)、左心室舒张末压(LVEDP)、左室压力最大上升速率(+dp/dtmax)以及左室压力最大下降速率(-dp/dtmax)。结果4周时模型组HR、+dp/dtmax和-dp/dtmax绝对值均低于假手术组(P<0.05),LVEDP则高于假手术组(P<0.05)。随着手术大鼠例数增多,存活率得到提高(P<0.05)。结论心肌梗死后4周形成心力衰竭模型,通过经口气管插管法、选择结扎冠状动脉分支末梢部位、增加手术操作熟练程度,可提高动物存活率。 相似文献
62.
目的:评估人工流产(指手术流产)对乳腺癌危险性的可能影响。方法:研究在上海267040例妇女的一项乳房自我检查随机试验的队列人群中进行,由队列研究和巢式病例对照研究两部分组成。结果:依据基线调查表采集的资料分析,人工流产不增加乳腺癌危险性。调整潜在的混淆因素后,OR=1.06(95%CI:0.91~1.25)。人工流产次数增加无危险性趋势增加。从更详细的652例乳腺癌病例和694例对照资料分析,得出相似的结果。人工流产发生在首次生育后不增加危险性;少数妇女在首次生育前人工流产以及妊娠13周后人工流产,虽然被观察到危险性有增加,但无显著性统计学意义。结论:在中国,人工流产不是乳腺癌发生的重要原因。 相似文献
63.
64.
65.
A Papadopoulou MO Rawashdeh GA Brown AS McNeish IW Booth 《Acta paediatrica (Oslo, Norway : 1992)》1995,84(1):79-83
The short- and long-term effects of an elemental diet in children with acute Crohn's disease were compared with those of prednisolone in historical controls. Clinical remission was induced in 25 of 30 and in 18 of 28 episodes treated for six weeks with an elemental diet and prednisolone. Patients with proximal disease had longer remission after treatment with an elemental diet (p < 0.05) than did patients with colonic disease after treatment with prednisolone (p < 0.01). Disease activity index score improved in both groups compared with the pretreatment scores (p < 0.05). However, the improvement in the elemental diet group was significantly better than in the prednisolone group (p < 0.001). Changes in linear growth were better after treatment with an elemental diet compared with steroids (p < 0.001). Serum albumin and haematocrit concentrations all improved significantly in the children treated with an elemental diet (p < 0.001) but not in those treated with steroids. Thus an elemental diet was better than prednisolone in proximal disease and confirmed improved growth and nutritional status. 相似文献
66.
The quantitative nature of a visual task differentiates between ventral and dorsal stream 总被引:5,自引:0,他引:5
The aim of the present positron emission tomography (PET) study was to investigate how visual processing in dorsal and ventral streams depends on the quantitative nature of the task. In the same-different task, participants identified the presence of an orientation difference between two gratings, presented centrally in succession. In the quantification task, participants estimated the magnitude of the difference and compared it to a fixed standard. Detection of dimming of the fixation point was used as a control task. Visual input, motor responses, and performance were equated across tasks. Subtracting same-different from quantification yielded significant activation in the left superior parietal lobule and left ventral premotor cortex, consistent with results obtained in number-processing tasks. The reverse subtraction yielded activation in the right inferior temporal gyrus, in agreement with earlier results. These results demonstrate that a single attribute can be processed either in the ventral or dorsal stream, depending on the cognitive operations required by the tasks. 相似文献
67.
目的 探索层流洁净技术治疗大面积烧伤的价值。方法 对室内空气及创面进行细菌培养;监测病房使用时间的细菌微粒数比较,各洁净级别杀菌率。不同级别地点细菌培养结果比较。结果 千级以上层流病房细菌培养为“0”,与普通病房对照有较大差别,患者死亡率明显降低,疗程缩短,医疗费用下降,手术植皮及其他伤口均达Ⅰ期愈合,无交叉感染。结论 层流洁净病房应用于烧伤治疗,疗效非常满意。 相似文献
68.
69.
Resistance of Copenhagen rats to chemical induction of glutathione S- transferase 7-7-positive liver foci 总被引:2,自引:0,他引:2
Copenhagen (Cop) rats are completely resistant to the chemical induction of
mammary adenocarcinomas, but their susceptibility to hepatocarcinogenesis
is virtually unknown. Rat liver is a well- characterized and easily
manipulated tissue in which to study carcinogenesis. Therefore, if Cop rats
are resistant to hepatocarcinogenesis, studies into resistance mechanisms
may be feasible. Male Cop and F344 rats, 7-8 weeks old, were initiated
using either N-nitrosodiethylamine (DEN) (200 mg/kg, i.p.) or a two-thirds
partial hepatectomy (PH) followed by N-methyl-N-nitrosourea (MNU) (60
mg/kg, i.p.). The rats were then promoted using a modified resistant
hepatocyte (RH) protocol (a combination of four doses of 2-
acetylaminofluorene (2-AAF) and a single dose of CCl4 that provides a
selective mitotic stimulus for initiated cells). Six weeks after initiation
the rats were killed and liver sections were stained for glutathione
S-transferase 7-7 (GST 7-7), a marker for putative preneoplastic
hepatocytes. Cop rats were found to be highly resistant, having a
approximately 9- and approximately 27-fold smaller percentage of liver area
occupied by GST 7-7-positive foci than susceptible F344 rats following
initiation by DEN and MNU respectively. Furthermore, gross liver nodules
did not form in any of the Cop rats, whereas all F344 rat livers contained
nodules. Hepatic necrosis caused by DEN during initiation, and CCl4 during
promotion is necessary to stimulate compensatory hepatocyte division. We
demonstrated that these agents do indeed increase serum transaminase levels
and produce histologic evidence of necrosis in Cop rats. In order for liver
foci to grow rapidly in the RH protocol, the surrounding normal hepatocytes
must be mito-inhibited by 2-AAF. We found that the degree of
mito-inhibition of normal hepatocytes by 2-AAF is the same in Cop and F344
rats. These results show that the Cop rat is highly resistant to the
chemical induction of putative preneoplastic liver foci and nodules.
相似文献
70.
GA McCarthy B Kampmann V Novelli RF Miller DE Mercey D Gibb 《Archives of disease in childhood》1996,74(5):455-457
AIDS related Kaposi's sarcoma is commonly seen in homosexual men, only occasionally in men and women with heterosexually acquired HIV, and extremely rarely in children. The case of an HIV infected mother and her vertically infected child who both developed visceral Kaposi's sarcoma is reported. It is proposed that the putative Kaposi's sarcoma agent may also be transmitted vertically. 相似文献