全文获取类型
收费全文 | 7447篇 |
免费 | 490篇 |
国内免费 | 152篇 |
专业分类
耳鼻咽喉 | 47篇 |
儿科学 | 138篇 |
妇产科学 | 99篇 |
基础医学 | 842篇 |
口腔科学 | 243篇 |
临床医学 | 504篇 |
内科学 | 1303篇 |
皮肤病学 | 41篇 |
神经病学 | 753篇 |
特种医学 | 322篇 |
外国民族医学 | 2篇 |
外科学 | 634篇 |
综合类 | 518篇 |
预防医学 | 852篇 |
眼科学 | 168篇 |
药学 | 1036篇 |
1篇 | |
中国医学 | 229篇 |
肿瘤学 | 357篇 |
出版年
2023年 | 89篇 |
2022年 | 252篇 |
2021年 | 333篇 |
2020年 | 198篇 |
2019年 | 270篇 |
2018年 | 237篇 |
2017年 | 225篇 |
2016年 | 227篇 |
2015年 | 212篇 |
2014年 | 403篇 |
2013年 | 640篇 |
2012年 | 291篇 |
2011年 | 384篇 |
2010年 | 307篇 |
2009年 | 311篇 |
2008年 | 358篇 |
2007年 | 344篇 |
2006年 | 282篇 |
2005年 | 258篇 |
2004年 | 254篇 |
2003年 | 195篇 |
2002年 | 175篇 |
2001年 | 152篇 |
2000年 | 130篇 |
1999年 | 117篇 |
1998年 | 111篇 |
1997年 | 120篇 |
1996年 | 104篇 |
1995年 | 98篇 |
1994年 | 68篇 |
1993年 | 92篇 |
1992年 | 66篇 |
1991年 | 54篇 |
1990年 | 66篇 |
1989年 | 59篇 |
1988年 | 73篇 |
1987年 | 54篇 |
1986年 | 47篇 |
1985年 | 68篇 |
1984年 | 54篇 |
1983年 | 42篇 |
1982年 | 54篇 |
1981年 | 44篇 |
1980年 | 29篇 |
1979年 | 37篇 |
1978年 | 24篇 |
1977年 | 19篇 |
1976年 | 12篇 |
1975年 | 12篇 |
1974年 | 10篇 |
排序方式: 共有8089条查询结果,搜索用时 15 毫秒
1.
Spleen sizing by ultrasound in polycythaemia and thrombocythaemia: comparison with SPECT 总被引:3,自引:1,他引:2
M. Messinezy L. M. MacDonald T. O. Nunan N. B. Westwood S. Chinn & T. C. Pearson 《British journal of haematology》1997,98(1):103-107
Detection of non-palpable early splenic enlargement may aid diagnosis of primary polycythaemia (PP) and primary thrombocythaemia (PT). In this study linear spleen sizing by ultrasound has been compared with spleen volume estimation by single photon emission computerized tomography (SPECT) in 26 patients. Spleen length by ultrasound correlated well with SPECT volume estimation.
Ultrasound spleen length was also measured in 60 normal control subjects where the upper limit of the 95% reference range was 11.6 cm. Changes in spleen length with both age and body weight were substantial and overshadowed the imperfect reproducibility of this method. Therefore, interpretation of an individual's measured spleen length should be in relation to that predicted for adults of the same age and weight, particularly at the extremes of the younger, heavier patients and also the older, lighter patients.
Ultrasound spleen lengths of different patient groups (21 PP, 26 PT, 17 idiopathic erythrocytosis, 12 secondary polycythaemia, nine apparent polycythaemia) were compared both using the measured overall reference range and the differences from the values predicted for their age and weight. The comparison showed that almost all patients with PP whose spleens were not palpable had spleen lengths greater than the upper limit for the normal control group, but separation from the other patient groups was incomplete.
Detection of non-palpable splenomegaly by ultrasound length should remain a 'minor' criterion amongst the 'proposed modified diagnostic criteria' of PP. 相似文献
Ultrasound spleen length was also measured in 60 normal control subjects where the upper limit of the 95% reference range was 11.6 cm. Changes in spleen length with both age and body weight were substantial and overshadowed the imperfect reproducibility of this method. Therefore, interpretation of an individual's measured spleen length should be in relation to that predicted for adults of the same age and weight, particularly at the extremes of the younger, heavier patients and also the older, lighter patients.
Ultrasound spleen lengths of different patient groups (21 PP, 26 PT, 17 idiopathic erythrocytosis, 12 secondary polycythaemia, nine apparent polycythaemia) were compared both using the measured overall reference range and the differences from the values predicted for their age and weight. The comparison showed that almost all patients with PP whose spleens were not palpable had spleen lengths greater than the upper limit for the normal control group, but separation from the other patient groups was incomplete.
Detection of non-palpable splenomegaly by ultrasound length should remain a 'minor' criterion amongst the 'proposed modified diagnostic criteria' of PP. 相似文献
2.
3.
The calculation of the extent of the ring scotoma around positive lenses, as conventionally taught to students of clinical optics, indicates that the scotoma is of a significant size. Using knife-edge lenses this study shows that the calculations are invalid due to the finite size of the eye's entrance pupil and in many instances the scotoma is shown not to exist. The effect noticed in clinical practice is probably largely due to the frame and the edging techniques used which add to the refractive scotoma which is present with high powered lenses, large apertures and/or small pupil sizes. 相似文献
4.
Y. Spyckerelle B. Herbeth J.-P. Deschamps ‡ 《Journal of human nutrition and dietetics》1992,5(3):161-168
The dietary history method was used to determine the total energy and macronutrient intake, the distribution of daily energy from the different meals and the energy contribution of various food groups, in a population of 299 boys, aged between 10 and 15 years. The effects of age, the social status of the father (SPS), the ponderal index, the importance of breakfast or lunch, and the level of energy intake on dietary indicators, were studied. In our population, energy intake increased with increasing age but the energy contribution of macronutrients did not vary. The diet of boys whose fathers were in the upper SPS classes differed from the diet of those boys whose fathers were manual workers: for example they consumed less energy and pastries, but more animal protein (in percentage of energy intake), more dairy products, and more fruit. The ponderal index was negatively related to energy intake but positively related to protein intake, especially from meat and meat products. The energy intake from protein, animal protein and the energy contribution of dairy products, meat and meat products, fish and vegetables was lower among large eaters than among small eaters. The energy contribution of pastries, sugar and sweets was higher among large eaters.
Similarily, the energy intake from morning and evening snacks was also higher among large eaters. It should be noted that boys who had a substantial breakfast took in less energy from all other meals (including snacks and main meals). Such informaton is necessary in order to develop an effective health programme. 相似文献
Similarily, the energy intake from morning and evening snacks was also higher among large eaters. It should be noted that boys who had a substantial breakfast took in less energy from all other meals (including snacks and main meals). Such informaton is necessary in order to develop an effective health programme. 相似文献
5.
6.
脑梗死急性期对血压和颅压的控制极为重要,若措施得当,可大大降低病死率和致残率。笔者结合临床工作经验总结体会如下:脑梗死急性期对血压和颅压的控制极为重要,若措施得当,可大大降低病死率和致残率,笔者结合临床工作经验总结体会如下。 相似文献
7.
Chun-Hsiung Huang Fang-Yuan Ho Hon-Ming Ma Chan-Tsung Yang Jiann-Jong Liau Hung-Chan Kao Tai-Horng Young Cheng-Kung Cheng 《Journal of orthopaedic research》2002,20(5):1038-1041
Osteolysis induced by ultrahigh molecular weight polyethylene wear debris has been recognized as the major cause of long-term failure in total joint arthroplasties. In a previous study, the prevalence of intraoperatively identified osteolysis during primary revision surgery was much higher in mobile bearing knee replacements (47%) than in fixed bearing knee replacements (13%). We postulated that mobile bearing knee implants tend to produce smaller sized particles. In our current study, we compared the particle size and morphology of polyethylene wear debris between failed mobile bearing and fixed bearing knees. Tissue specimens from interfacial and lytic regions were extracted during revision surgery of 10 mobile bearing knees (all of the low contact stress (LCS) design) and 17 fixed bearing knees (10 of the porous-coated anatomic (PCA) and 7 of the Miller/Galante design). Polyethylene particles were isolated from the tissue specimens and examined using both scanning electron microscopy and light-scattering analyses. The LCS mobile bearing knees produced smaller particulate debris (mean equivalent spherical diameter: 0.58 microm in LCS, 1.17 microm in PCA and 5.23 microm in M/G) and more granular debris (mean value: 93% in LCS, 77% in PCA and 15% in M/G). 相似文献
8.
9.
10.
Previous reports in the literature have described correlation of increasing repeat length with severity of the phenotype, in Kennedy syndrome. We describe male siblings with different repeat lengths, with lack of expression of the phenotype in the sibling with the longer repeat length. The phenotype was identical to motor neurone disease. There is variability of expression in Kennedy syndrome and repeat length even in siblings cannot be taken as a conclusive indicator of severity. CAG repeat length cannot be used to predict the natural history of Kennedy disease. The diagnosis of Kennedy syndrome should be considered in male patients presenting with atypical motor neurone disease. 相似文献