全文获取类型
收费全文 | 2932篇 |
免费 | 237篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 80篇 |
妇产科学 | 45篇 |
基础医学 | 486篇 |
口腔科学 | 23篇 |
临床医学 | 316篇 |
内科学 | 741篇 |
皮肤病学 | 29篇 |
神经病学 | 211篇 |
特种医学 | 220篇 |
外国民族医学 | 1篇 |
外科学 | 324篇 |
综合类 | 72篇 |
一般理论 | 6篇 |
预防医学 | 224篇 |
眼科学 | 25篇 |
药学 | 186篇 |
中国医学 | 16篇 |
肿瘤学 | 196篇 |
出版年
2023年 | 15篇 |
2022年 | 31篇 |
2021年 | 63篇 |
2020年 | 33篇 |
2019年 | 55篇 |
2018年 | 57篇 |
2017年 | 46篇 |
2016年 | 43篇 |
2015年 | 56篇 |
2014年 | 62篇 |
2013年 | 109篇 |
2012年 | 170篇 |
2011年 | 190篇 |
2010年 | 113篇 |
2009年 | 91篇 |
2008年 | 119篇 |
2007年 | 162篇 |
2006年 | 133篇 |
2005年 | 121篇 |
2004年 | 125篇 |
2003年 | 99篇 |
2002年 | 95篇 |
2001年 | 95篇 |
2000年 | 99篇 |
1999年 | 63篇 |
1998年 | 64篇 |
1997年 | 62篇 |
1996年 | 69篇 |
1995年 | 35篇 |
1994年 | 33篇 |
1993年 | 49篇 |
1992年 | 60篇 |
1991年 | 45篇 |
1990年 | 56篇 |
1989年 | 55篇 |
1988年 | 63篇 |
1987年 | 52篇 |
1986年 | 35篇 |
1985年 | 44篇 |
1984年 | 24篇 |
1983年 | 29篇 |
1982年 | 33篇 |
1981年 | 18篇 |
1980年 | 20篇 |
1979年 | 20篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 25篇 |
1975年 | 12篇 |
1974年 | 8篇 |
排序方式: 共有3207条查询结果,搜索用时 9 毫秒
51.
Gina L. Trakman Winnie Y. Y. Lin Amy L. Hamilton Amy L. Wilson-OBrien Annalise Stanley Jessica Y. Ching Jun Yu Joyce W. Y. Mak Yang Sun Junkun Niu Yinglei Miao Xiaoqing Lin Rui Feng Minhu Chen Nitin Shivappa James R. Hebert Mark Morrison Siew C. Ng Michael A Kamm 《Nutrients》2022,14(17)
(1) Background: Developing countries have experienced a rapid recent rise in Inflammatory Bowel Disease (IBD) incidence and emerging evidence suggests processed foods and food additives may predispose one to the development and perpetuation of Crohn’s disease (CD). The aim of this study was to evaluate processed food and food additive intake in CD patients and controls, in Australia (high CD incidence), Hong Kong (intermediate incidence) and mainland China (emerging incidence). (2) Methods: In 274 CD patients (CD), 82 first-degree relatives (FDR), 83 household members (HM) and 92 healthy unrelated controls (HC) from Australia (n = 180), Hong Kong (HK) (n = 160) and mainland China (n = 191) we estimated early life (0–18 years), recent (12 months), and current processed and food additive intake, using validated questionnaires and a 3-day-food diary. (3) Results: Early life processed food intake: Combining all regions, CD were more likely to have consumed soft drinks and fast foods than HM, more likely to have consumed processed fruit and snacks than their FDR, and more likely to have consumed a range of processed foods than HC. HK and China CD patients were more likely to have consumed a range of processed foods than HC. Recent food-additive intake (12-months): Combining all regions, CD patients had significantly higher intakes of aspartame and sucralose, and polysorbate-80, than HC, and more total emulsifiers, artificial sweeteners, and titanium dioxide than FDR and HC. HK and China CD patients had a higher intake of almost all food additives than all controls. Current additive intake (3-days): Australian and HK CD patients had higher total food-additive intake than FDR, and HK CD patients had a higher intake of total food-additives and emulsifiers than HM. (4) Conclusions: CD patients have been exposed to more processed food and food additives than control groups, which may predispose them to CD development and ongoing inflammation. 相似文献
52.
用离体大鼠肝脏灌流方法,研究了胆碱酯酶抑制剂CXN的生物转化过程。径HPLC分离纯化及光谱分析,鉴定了CXN的六个脂溶性代谢产物的化学结构。产物Ⅰ为CXN原形,其余均为氧化产物。其中产物Ⅲ尚保留部分抑酶活力,而产物Ⅱ,Ⅴ及Ⅵ对小鼠全脑胆碱酯酶的抑酶活力明显下降。另外还观察到,代谢产物Ⅱ及Ⅴ对小鼠的急性毒性也明显减小。 相似文献
53.
静松灵[2-(2,4-二甲基苯胺基)-4,5-二氢噻唑,XT]是国内合成的麻醉物,经ip给药后,从大鼠尿中分离、纯化、鉴定了四个代谢产物。MB1即XT原形;MB3及MA2互为异构体,分别为2位、4位甲基氧化为羧基的产物;MA1则4位甲基氧化为羧基,二氢噻唑环中41位亚甲基氧化为羰基。初步实验表明:代谢产物MB3,MA2,MA1的药效与毒性均远低于原形药,大鼠与小鼠对XT的转化机制相近,但也存在种属的差异。 相似文献
54.
Fan Huang Peng Xia Varut Vardhanabhuti SaiKam Hui KuiKai Lau Henry KaFung Mak Peng Cao 《Human brain mapping》2023,44(4):1344
This study proposed a semisupervised loss function named level‐set loss (LSLoss) for cerebral white matter hyperintensities (WMHs) segmentation on fluid‐attenuated inversion recovery images. The training procedure did not require manually labeled WMH masks. Our image preprocessing steps included biased field correction, skull stripping, and white matter segmentation. With the proposed LSLoss, we trained a V‐Net using the MRI images from both local and public databases. Local databases were the small vessel disease cohort (HKU‐SVD, n = 360) and the multiple sclerosis cohort (HKU‐MS, n = 20) from our institutional imaging center. Public databases were the Medical Image Computing Computer‐assisted Intervention (MICCAI) WMH challenge database (MICCAI‐WMH, n = 60) and the normal control cohort of the Alzheimer''s Disease Neuroimaging Initiative database (ADNI‐CN, n = 15). We achieved an overall dice similarity coefficient (DSC) of 0.81 on the HKU‐SVD testing set (n = 20), DSC = 0.77 on the HKU‐MS testing set (n = 5), and DSC = 0.78 on MICCAI‐WMH testing set (n = 30). The segmentation results obtained by our semisupervised V‐Net were comparable with the supervised methods and outperformed the unsupervised methods in the literature. 相似文献
55.
灰黄霉素中灰黄霉酸杂质及色泽的考查 总被引:1,自引:0,他引:1
常仁厚 《中国现代应用药学》1998,15(5):44-45
目的:本文采用薄层色谱法考查了不同厂家灰黄霉素中灰黄霉酸杂质的存在.方法:以丙酮为溶媒,精制灰黄霉素,摸索分离条件,探讨杂质限度,考查产品色泽.结果:杂质均值为0.276%,RSD为0.168%.结论:对改进产品检验方法、提高产品质量具有一定的参考价值. 相似文献
56.
In heart failure with reduced ejection fraction (HFrEF), diminished tonic and reflex vagal heart rate modulation and exaggerated sympathetic outflow and neural norepinephrine release are evident from disease inception. Each of these disturbances of autonomic regulation has been independently associated with shortened survival, and β-adrenoceptor antagonism and therapeutic autonomic modulation by other means have been demonstrated, in clinical trials, to lessen symptoms and prolong survival. In contrast, data concerning the autonomic status of patients with heart failure with preserved ejection fraction (HFpEF) are comparatively sparse. Little is known concerning the prognostic consequences of autonomic dysregulation in such individuals, and therapies applied with success in HFrEF have in most trials failed to improve symptoms or survival of those with HFpEF. A recent HFpEF Expert Scientific Panel report emphasised that without a deeper understanding of the pathophysiology of HFpEF, establishing effective treatment will be challenging. One aspect of such pathology may be cardiovascular autonomic disequilibrium, often worsened by acute exercise or routine daily activity. This review aims to summarise existing knowledge concerning parasympathetic and sympathetic function of patients with HFpEF, consider potential mechanisms and specific consequences of autonomic disturbances that have been identified, and propose hypotheses for future investigation. 相似文献
57.
The essential adaptive food selection behavior of young children has become increasingly medicalized as a kind of disease—the “picky-eating” syndrome in Hong Kong. The researcher used the multiple case studies approach with data collected from in-depth interviews and advertisements to examine the process of the medicalization of picky-eating disorder, which demonstrates how an essential adaptive human behavior can be redefined by the market and medical system as a deviant, abnormal behavior that needs to be eliminated and how the resulting health risks can be resolved by modern medicine produced by this pharmaceutical nexus. 相似文献
58.
Mak Anselm Thornhill Susannah I Lee Hui Yin Lee Bernett Poidinger Michael Connolly John E Fairhurst Anna-Marie 《Clinical rheumatology》2018,37(3):811-816
Clinical Rheumatology - The signalling lymphocyte activation molecule (SLAM) family receptors play important roles in modulating immune responses. Previous studies in murine models and patients... 相似文献
59.
Wen-Sheng Tzeng Reng-Hong Wu Steven Kuan-Hua Huang Chee-Wai Mak Alex Chien-Hwa Liao Victor Chia-Hsiang Lin 《Clinical imaging》2012,36(6):773-779
Radiologists and urologists require practical and helpful image reconstructions for diagnosing urinary obstruction. We performed different types of imaging and reconstruction, then used a self-designed urinary obstruction-specific questionnaire to evaluate the diagnostic outcome of them. Our results suggested that two-dimensional (2D) axial computed tomography (CT) is clinically superior to retrograde pyelography or antegrade pyelography, and to other modes of image reconstruction that are often used for diagnosing urinary obstruction. 相似文献