全文获取类型
收费全文 | 3549篇 |
免费 | 230篇 |
国内免费 | 174篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 13篇 |
妇产科学 | 21篇 |
基础医学 | 202篇 |
口腔科学 | 134篇 |
临床医学 | 132篇 |
内科学 | 310篇 |
皮肤病学 | 60篇 |
神经病学 | 75篇 |
特种医学 | 63篇 |
外科学 | 76篇 |
综合类 | 394篇 |
现状与发展 | 1篇 |
预防医学 | 654篇 |
眼科学 | 12篇 |
药学 | 1229篇 |
中国医学 | 383篇 |
肿瘤学 | 184篇 |
出版年
2024年 | 8篇 |
2023年 | 59篇 |
2022年 | 140篇 |
2021年 | 150篇 |
2020年 | 107篇 |
2019年 | 100篇 |
2018年 | 99篇 |
2017年 | 119篇 |
2016年 | 139篇 |
2015年 | 118篇 |
2014年 | 179篇 |
2013年 | 351篇 |
2012年 | 188篇 |
2011年 | 246篇 |
2010年 | 167篇 |
2009年 | 148篇 |
2008年 | 181篇 |
2007年 | 162篇 |
2006年 | 137篇 |
2005年 | 138篇 |
2004年 | 117篇 |
2003年 | 96篇 |
2002年 | 77篇 |
2001年 | 66篇 |
2000年 | 66篇 |
1999年 | 45篇 |
1998年 | 51篇 |
1997年 | 51篇 |
1996年 | 35篇 |
1995年 | 35篇 |
1994年 | 42篇 |
1993年 | 36篇 |
1992年 | 27篇 |
1991年 | 26篇 |
1990年 | 39篇 |
1989年 | 21篇 |
1988年 | 20篇 |
1987年 | 23篇 |
1986年 | 16篇 |
1985年 | 18篇 |
1984年 | 17篇 |
1983年 | 4篇 |
1982年 | 13篇 |
1981年 | 9篇 |
1980年 | 9篇 |
1979年 | 10篇 |
1978年 | 12篇 |
1977年 | 13篇 |
1976年 | 7篇 |
1975年 | 6篇 |
排序方式: 共有3953条查询结果,搜索用时 24 毫秒
31.
目的 定量研究血液灌流对有机磷农药硫线磷和其解毒药阿托品的吸附作用.方法 模拟临床血液灌流装置,对含硫线磷和硫酸阿托品的血样进行灌流吸附,分别用毛细管气相色谱法和高效液相色谱法测定硫线磷和硫酸阿托品的残留量.结果 吸附剂用量为0.5、1.0和1.5 g,包膜活性炭在灌流2.0 h后硫线磷的清除率均能达到90%以上,硫酸阿托品的清除率依次为61.9%、84.9%和88.9%;HA230树脂在灌流1.5 h后硫线磷清除率都达到90%以上,硫酸阿托品的清除率也依次高达88.0%、97.2%和98.4%;包膜活性炭灌流3.0h后,硫酸阿托品与硫线磷的比值最高为灌流前的10.1倍,而HA230树脂灌流后,此比值最高为灌流前的6.7倍.结论 包膜活性炭和HA230吸附树脂血液灌流1.5~2.0 h均能清除血中大部分硫线磷,而且均能增加血中硫酸阿托品和硫线磷浓度的比值. 相似文献
32.
取因职业而接触乙烯类或苯类的孕妇静脉血和他们新生儿脐带血进行SCE和MN测定。发现接触乙烯类或苯类的母血SCE(8.55±0.84,9.44±1.12)均高于对照组(7.68±1.40),他们新生儿脐带血SCE(8.94±1.43,8.75±0.88)也高于对照组(6.71±1.27)。接触乙烯类和苯类的母血微核率(0.833‰,0.727‰),高于对照组(0.267‰),他们新生儿脐血微核率(0.75‰,0.818‰)也高于对照组(0.267‰)。我们还发现母亲孕期被动吸烟增强了这两类诱变剂对他们后代的遗传毒性。 相似文献
33.
Summary This short paper summarizes the basic concept and the technology of a new computed radiographic system which uses an energy-storage phosphorus panel called Imaging Plate as an image sensor. The Imaging Plate can be used to obtain radiographs in exactly the same way as the screen-film combination is used in conventional radiography. The system eliminates the drawbacks of conventional screen-film radiography by combining digital image processing and digitization of the x-ray energy pattern utilizing scanning laser stimulated luminescence.The major part of this paper was originally delivered at the 1984 AAPM Annual Summer School which was held on July 22–27 at University of Notre Dame, USA. Modified for the publication in the Neurosurgical Review. 相似文献
34.
Maria Ruiz-Castell Gwenaëlle Le Coroller Jean-Francois Landrier Djedgiga Kerkour Bernard Weber Guy Fagherazzi Brice M. R. Appenzeller Michel Vaillant Torsten Bohn 《Nutrients》2021,13(1)
Metabolic syndrome (MetS) characteristics include chronic inflammation and elevated oxidative stress. This study assessed associations between circulating concentrations of micronutrients/phytochemicals and inflammatory/oxidative stress markers with MetS and MetS components. Adults (N = 606) from the European Health Examination Survey in Luxembourg (2013–2015) were randomly selected. We performed a multivariable logistic regression model using the least absolute shrinkage and selection operator to identify MetS-associated variables. Participants with MetS had higher concentrations of C-reactive protein (CRP), 8-iso-prostaglandin F2α, leptin, insulin, and vitamins E/A, but lower concentrations of adiponectin, beta-carotene, and oxidized low-density lipoprotein. A one-unit increase in log-CRP was associated with 51% greater odds of MetS (OR = 1.51 (95% CI: 1.16, 1.98)). Adults with a one-unit increase in log-leptin were 3.1 times more likely to have MetS (3.10 (2.10, 4.72)). Women with a one-unit increase in vitamin A were associated with 3% increased odds of MetS (1.03 (1.01, 1.05)), while those with a one-unit increase in log-adiponectin were associated with 82% decreased odds (0.18 (0.07, 0.46)). Chronic inflammation best characterized adults with MetS, as CRP, adiponectin, and leptin were selected as the main MetS determinants. Micronutrients did not seem to affect MetS, except for vitamin A in women. 相似文献
35.
This paper continues the systematic review on proanthocyanidins and flavan-3-ols in the prevention and treatment of periodontal disease and covers the immunomodulatory effects, and animal- and clinical studies, while the other part discussed the direct antibacterial properties. Inflammation as a major response of the periodontal tissues attacked by pathogenic microbes can significantly exacerbate the condition. However, the bidirectional activity of phytochemicals that simultaneously inhibit bacterial proliferation and proinflammatory signaling can provide a substantial alleviation of both cause and symptoms. The modulatory effects on various aspects of inflammatory and overall immune response are covered, including confirmed and postulated mechanisms of action, structure activity relationships and molecular targets. Further, the clinical relevance of flavan-3-ols and available outcomes from clinical studies is analyzed and discussed. Among the numerous natural sources of flavan-3-ols and proanthocyanidins the most promising are, similarly to antibacterial properties, constituents of various foods, such as fruits of Vaccinium species, tea leaves, grape seeds, and tannin-rich medicinal herbs. Despite a vast amount of in vitro and cell-based evidence of immunomodulatory there are still only a few animal and clinical studies. Most of the reports, regardless of the used model, indicated the efficiency of these phytochemicals from cranberries and other Vaccinium species and tea extracts (green or black). Other sources such as grape seeds and traditional medicinal plants, were seldom. In conclusion, the potential of flavan-3-ols and their derivatives in prevention and alleviation of periodontal disease is remarkable but clinical evidence is urgently needed for issuing credible dietary recommendation and complementary treatments. 相似文献
36.
Francesca Oliviero Paola Galozzi Anna Scanu Francesca Galuppini Vanni Lazzarin Silvia Brocco Giampietro Ravagnan Paolo Sfriso Roberta Ramonda Paolo Spinella Leonardo Punzi Gianmaria Pennelli Roberto Luisetto 《Nutrients》2021,13(3)
Background: Polydatin is a stilbenoid with important antioxidant, anti-inflammatory, and immunomodulating properties. The aim of this study was to assess the anti-inflammatory preventive effect of polydatin in the mouse model of acute arthritis induced by calcium pyrophosphate (CPP) crystals. Methods: Acute arthritis was induced by the injection of a suspension of sterile CPP crystals into the ankle joint of Balb/c mice. Animals were randomized to receive polydatin or colchicine (the control drug) according to a prophylactic and a therapeutic protocol. The primary outcome was the variation of ankle swelling obtained after crystal injection and treatment, while histological parameters such as leukocyte infiltration, IL-1ß and CXCL1 levels and tissue expression were considered as secondary outcomes. Results: Prophylactic treatment with PD significantly diminished ankle swelling after 48 h from crystal injection. Secondary outcomes such as leukocyte infiltration, necrosis, edema, and synovitis were also decreased. PD caused a reduction in circulating levels of IL-1ß and CXCL1, as well as their tissue expression. By contrast, the therapeutic administration of PD did not have any beneficial effect. Conclusions: PD can effectively prevent acute inflammatory response to crystals in the mouse model of CPP crystal-induced arthritis. These results suggest that this bioactive compound might be used in the prevention of crystal-induced acute attacks in humans. 相似文献
37.
Jing Sun Xianyang Chen Yongru Wang Yuelin Song Bo Pan Bei Fan Fengzhong Wang Xiaonan Chen Pengfei Tu Jiarui Han Huixia Huo Jun Li 《中草药(英文版)》2023,15(3):430-438
Objective: The present study aimed to evaluate the therapeutic effect and explore the underlying mechanisms of Longxue Tongluo Capsule (LTC) on ischemic stroke rats.
Methods: Twenty-six rats were randomly divided into four groups, including sham group, sham + LTC group, MCAO group, and MCAO + LTC group. Ischemic stroke rats were simulated by middle cerebral artery occlusion (MCAO), and LTC treatment group were orally administrated with 300 mg/kg of LTC once daily for seven consecutive days. LTC therapy was validated in terms of neurobehavioral abnormality evaluation, cerebral infarct area, and histological assessments. The plasma metabolome comparisons amongst different groups were conducted by UHPLC-Q Exactive MS in combination with subsequent multivariate statistical analysis, aiming to finding the molecules in respond to the surgery or LTC treatment.
Results: Intragastric administration of LTC significantly decreased not only the neurobehavioral abnormality scores but also the cerebral infarct area of MCAO rats. The interstitial edema, atrophy, and pyknosis of glial and neuronal cells occurred in the infarcted area, core area, and marginal area of cerebral cortex were improved after LTC treatment. A total of 13 potential biomarkers were observed, and Youden index of 11 biomarkers such as LysoPC, SM, and PE were more than 0.7, which were involved in neuroprotective process. The correlation and pathway analysis showed that LTC was beneficial to ischemic stroke rats via regulating glycerophospholipid and sphingolipid metabolism, together with nicotinate and nicotinamide metabolism. Heatmap and ternary analysis indicated the synergistic effect of carbohydrates and lipids may be induced by flavonoid intake from LTC.
Conclusion: The present study could provide evidence that metabolomics, as systematic approach, revealed its capacity to evaluate the holistic efficacy of TCM, and investigate the molecular mechanism underlying the clinical treatment of LTC on ischemic stroke. 相似文献
38.
39.
Michael H. Erhard Reiner Kühlmann Ladislaus Szinicz Uli Lösch 《Archives of toxicology》1990,64(7):580-585
The development of a specific and sensitive immunologic ELISA detection system for methylphosphonoflouridic acid. 1,2,2-trimethylpropylester (soman) by the use of monoclonal antibodies (MAbs) is described. The monoclonal antibodies F71D7, F71H10, F71B12 and F71H9 originally produced against the soman derivative methyl phosphonic acid,p-aminophenyl 1,2,2-trimethylpropyldiester (MATP) also reacted with soman in a previously developed, direct competitive ELISA. After optimizing the ELISA system by varying the reaction mixture and the solvents for the organophosphate, 5.0×10–7 mol/l soman (80% purity), e.g. 2.5 ng or 2 ng pure soman per 25 l test buffer, could be detected after a total test duration of 40 min. A shortening of the incubation time to 10 min resulted in a drop of sensitivity to 1.8×10–6 mol/l soman. Various alcohols which may be used as extraction media for soman from various materials (isopropanol, ethanol and methanol) were shown to inhibit peroxidase activity and thereby reduce the sensitivity of the test. However, the influence of alcohols decreased with the shortening of incubation time. All monoclonal antibodies showed little cross reactivity to sarin and no cross reactivity to tabun and VX. Judging on the reactivity of the MAbs with MATP and soman oxidazed by 1,2-dihydrobenzol, some reactivity with some other (non-toxic) soman analogues containing the same pinacolyl group can be expected. There was no evidence for stereoselectivity of the MAbs tested. Finally, soman could be detected in different biological samples like human serum, goat serum, rabbit serum, chicken serum, milk, and tap water in concentrations between 1.3×10–6 and 2.0×10–6 mol/l. 相似文献
40.
四乙基胺抑制蟾酥的强心效应 总被引:1,自引:0,他引:1
[目的]观察蟾酥对离体蟾蜍心脏收缩运动的影响和各种受体阻断剂、钾通道阻断剂对这种效应的影响。[方法]将离体蟾蜍心脏收缩运动用张力换能器转换成电信号,通过Doctor-95 Super Lab软件系统在电脑上连续记录心率和收缩力的变化,并打印成曲线。[结果]取自蟾蜍同体耳后腺的蟾酥对离体蟾蜍心脏收缩运动有增强作用。M受体阻断剂阿托品(0.5g/L)和β受体阻断剂心得安(0.01g/L)不能阻断蟾酥对离体蟾蜍心脏收缩运动的增强作用,而α受体阻断剂酚妥拉明(0.5g/L)、非选择性钾通道阻断剂四乙基胺(10mmol/L)则明显抑制蟾酥对离体蟾蜍心脏收缩运动的增强作用。[结论]蟾酥是通过α受体作用于钾通道而增强离体蟾蜍心脏收缩运动。 相似文献