全文获取类型
收费全文 | 47299篇 |
免费 | 3171篇 |
国内免费 | 1559篇 |
专业分类
耳鼻咽喉 | 686篇 |
儿科学 | 1248篇 |
妇产科学 | 766篇 |
基础医学 | 4613篇 |
口腔科学 | 1085篇 |
临床医学 | 5197篇 |
内科学 | 7459篇 |
皮肤病学 | 1951篇 |
神经病学 | 2612篇 |
特种医学 | 1119篇 |
外国民族医学 | 1篇 |
外科学 | 2173篇 |
综合类 | 6842篇 |
现状与发展 | 3篇 |
预防医学 | 4952篇 |
眼科学 | 642篇 |
药学 | 7267篇 |
32篇 | |
中国医学 | 2283篇 |
肿瘤学 | 1098篇 |
出版年
2024年 | 31篇 |
2023年 | 521篇 |
2022年 | 720篇 |
2021年 | 1678篇 |
2020年 | 1447篇 |
2019年 | 1297篇 |
2018年 | 1360篇 |
2017年 | 1408篇 |
2016年 | 1444篇 |
2015年 | 1563篇 |
2014年 | 2899篇 |
2013年 | 3351篇 |
2012年 | 2916篇 |
2011年 | 3144篇 |
2010年 | 2530篇 |
2009年 | 2359篇 |
2008年 | 2338篇 |
2007年 | 2432篇 |
2006年 | 2112篇 |
2005年 | 1981篇 |
2004年 | 1580篇 |
2003年 | 1415篇 |
2002年 | 1155篇 |
2001年 | 1067篇 |
2000年 | 904篇 |
1999年 | 858篇 |
1998年 | 703篇 |
1997年 | 682篇 |
1996年 | 577篇 |
1995年 | 568篇 |
1994年 | 509篇 |
1993年 | 412篇 |
1992年 | 469篇 |
1991年 | 414篇 |
1990年 | 340篇 |
1989年 | 346篇 |
1988年 | 331篇 |
1987年 | 294篇 |
1986年 | 248篇 |
1985年 | 274篇 |
1984年 | 213篇 |
1983年 | 180篇 |
1982年 | 201篇 |
1981年 | 146篇 |
1980年 | 132篇 |
1979年 | 103篇 |
1978年 | 87篇 |
1977年 | 69篇 |
1976年 | 53篇 |
1975年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
61.
Manish Gautam Santanu Saha Sarang Bani A. Kaul Sanjay Mishra Dada Patil N.K. Satti K.A. Suri Sunil Gairola K. Suresh Suresh Jadhav G.N. Qazi Bhushan Patwardhan 《Journal of ethnopharmacology》2009
Ethnopharmacological relevance
Roots of Asparagus racemosus Willd (Shatavari in vernacular) are widely used in Ayurveda as Rasayana for immunostimulation, galactogogue as also in treatment of conditions like ulcers and cancer. Various studies have indicated immunomodulatory properties of Shatavari root extracts and formulations.Aim of the study
To study the effect of standardized Asparagus racemosus root aqueous extract (ARE) on systemic Th1/Th2 immunity of SRBC sensitized animals.Materials and methods
We used HPTLC to quantify steroidal saponins (Shatavarin IV, Immunoside®) and flow cytometry to study effects of ARE on Th1/Th2 immunity. SRBC specific antibody titres and DTH responses were also monitored as markers of Th2 and Th1 responses, respectively. We also studied lymphocyte proliferation. Cyclosporin, cyclophosphamide and levamisole were used as controls.Results
Treatment with ARE (100 mg/(kg b.w. p.o.)) resulted in significant increase of CD3+ and CD4/CD8+ percentages suggesting its effect on T cell activation. ARE treated animals showed significant up-regulation of Th1 (IL-2, IFN-g) and Th2 (IL-4) cytokines suggesting its mixed Th1/Th2 adjuvant activity. Consistent to this, ARE also showed higher antibody titres and DTH responses. ARE, in combination with LPS, Con A or SRBC, produced a significant proliferation suggesting effect on activated lymphocytes.Conclusion
The study suggests mixed Th1/Th2 activity of ARE supports its immunoadjuvant potential. 相似文献62.
L.A. Fischer T. Menné C. Avnstorp G.B. Kasting† J.D. Johansen† 《The British journal of dermatology》2009,161(3):560-567
Background Hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC) is a synthetic fragrance ingredient. Case reports of allergy to HICC appeared in the 1980s, and HICC has recently been included in the European baseline series. Human elicitation dose–response studies performed with different allergens have shown a significant relationship between the patch-test threshold and the repeated open application test (ROAT) threshold, which mimics some real-life exposure situations. Fragrance ingredients are special as significant amounts of allergen may evaporate from the skin.
Objectives The study aimed to investigate the relationship between elicitation threshold doses at the patch test and the ROAT, using HICC as the allergen. The expected evaporation rate was calculated.
Materials and methods Seventeen HICC-allergic persons were tested with a dilution series of HICC in a patch test and a ROAT (duration up to 21 days). Seventeen persons with no HICC allergy were included as control group for the ROAT.
Results The response frequency to the ROAT (in μg HICC cm−2 per application) was significantly higher than the response frequency to the patch test at one of the tested doses. Furthermore the response rate to the accumulated ROAT dose was significantly lower at half of the doses compared with the patch test. The evaporation rate of HICC was calculated to be 72% over a 24-h period.
Conclusions The ROAT threshold in dose per area per application is lower than the patch test threshold; furthermore the accumulated ROAT threshold is higher than the patch test threshold, which can probably be explained by the evaporation of HICC from the skin in the open test. 相似文献
Objectives The study aimed to investigate the relationship between elicitation threshold doses at the patch test and the ROAT, using HICC as the allergen. The expected evaporation rate was calculated.
Materials and methods Seventeen HICC-allergic persons were tested with a dilution series of HICC in a patch test and a ROAT (duration up to 21 days). Seventeen persons with no HICC allergy were included as control group for the ROAT.
Results The response frequency to the ROAT (in μg HICC cm
Conclusions The ROAT threshold in dose per area per application is lower than the patch test threshold; furthermore the accumulated ROAT threshold is higher than the patch test threshold, which can probably be explained by the evaporation of HICC from the skin in the open test. 相似文献
63.
J. de Rotrou L. Battal-Merlet E. Wenisch C. Chausson E. Bizet F. Dray H. Lenoir A.-S. Rigaud O. Hanon 《European journal of neurology》2007,14(2):144-149
Within the context of early diagnosis of Alzheimer's disease (AD), there is a growing interest in neuropsychological screening tests. Amongst these tests, we focused on the largely used Memory Impairment Screen (MIS). The objective of the present work was to show that adding a 10-min delayed recall to the MIS, improves the test psychometric characteristics in order to detect dementia in the earliest stages. A prospective study was carried out on a cohort of 270 consecutive elderly ambulatory subjects attending the Broca Hospital Memory Clinic: normal controls ( n = 67), mild cognitive impairment subjects ( n = 98) and mildly demented patients [ n = 105, Mini Mental State Examination (MMSE) = 23 ± 4]. This study consisted in testing the advantage of the 10-min delayed recall entitled MIS-D compared with the MIS. At a cut-off score of 6, the MIS-D revealed satisfying psychometric characteristics with a sensitivity of 81% and a specificity of 91%, whilst the MIS alone indicated a sensitivity of 60% and a specificity of 88% in detecting dementia. In demented patients with MMSE score ≥26, MIS-D properties still remained satisfying (sensitivity: 75%, specificity: 92%). MIS-D is a more relevant screening test than MIS alone at very early stages of dementia. 相似文献
64.
Bacterial ghosts (BGs) are empty bacterial envelopes of Gram-negative bacteria produced by controlled expression of cloned gene E, forming a lysis tunnel structure within the envelope of the living bacteria. BGs are devoid of cytoplasmic content and possess all bacterial bio-adhesive surface properties in their original state while not posing any infectious threat. BGs are ideally suited as an advanced drug delivery system (ADDS) for toxic substances in tumor therapy. The inner space of BGs can be loaded with either single components or combinations of peptides, drugs or DNA which provides an opportunity to design new types of (polyvalent) drug delivery vehicles. Uptake of BGs loaded with Doxorubicin (Dox) by CaCo2 cells led to effective Dox release from endo-lysosomal compartments and accumulation in the nucleus. Viability and proliferative capacity of the cells were significantly decreased (2–3 orders of magnitude) after internalization of Dox loaded BGs as compared to cells incubated with free Dox. The same effect was observed with leukemia cells. Melanoma cells also revealed a high capability to internalize BGs. These results indicate that BGs are able to target a range of types of cancer. BGs have also been investigated as DNA delivery vectors. Studies show DNA loaded BGs are efficiently phagocytosed and internalized by both professional APCs and tumor cells with up to 82% of cells expressing the plasmid-encoded reporter gene. Our studies with BGs as an ADDS system contribute (i) to optimize drug delivery for the treatment of cancer; (ii) define specific conditions for selection and preparation of BG formulations; (iii) and provide a background for the clinical application of BGs in cancer therapy. 相似文献
65.
Jiqu Xu Shuang Rong Bijun Xie Zhida Sun Li Zhang Hailei Wu Ping Yao Yunjian Zhang Liegang Liu 《Phytotherapy research : PTR》2009,23(12):1742-1747
The major purpose of this study was to determine the effect of procyanidins extracted from the lotus seedpod (LSPC) on the learning and memory impairments induced by scopolamine (1 mg/kg, i.p.) in mice. The capacities of memory and learning were evaluated by the Morris water maze and the step‐down avoidance test. LSPC (50, 100, 150 mg/kg BW, p.o.) significantly reversed scopolamine‐induced learning and memory impairments in the Morris water maze test, as evaluated by shortened escape latency and swimming distance. In the step‐down avoidance test, LSPC (50, 100, 150 mg/kg BW, p.o.) treatment significantly reduced the number of errors and shortened latency compared with that of scopolamine. In addition, LSPC was also found to inhibit acetyl cholinesterase (AChE) activity. These results of this study suggest that LSPC may play a useful role in the treatment of cognitive impairment caused by AD and aging. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
66.
根据微动滑移振幅具有小位移的特点,设计制作了一种弓形传感装置,该装置能把小幅位移信号转换为电信号,并通过示波器实时显示出来,用这种测试装置来测量滑移式微动振幅具有测试方法简单而测试精度较高的优点。 相似文献
67.
平板运动试验阴性患者最大ST/HR斜率对冠心病的诊断价值 总被引:3,自引:1,他引:2
目的探讨平板运动试验阴性患者最大ST/HR斜率对冠心病的诊断价值.方法选择122例平板运动试验阴性而临床有明显冠心病指征的患者进行冠状动脉造影,测定其最大ST/HR斜率.结果平板运动试验阴性患者最大ST/HR斜率诊断冠心病的敏感性为68.2%,特异性为80.8%,准确性为76.2%;运动峰值心率<预计最大心率之85%组最大ST/HR斜率诊断冠心病的敏感性为92.8%,特异性为86.7%,准确性为89.7%,高于运动峰值心率≥预计最大心率之85%组.结论平板运动试验阴性患者最大ST/HR斜率对冠心病的临床诊断有较高的敏感性、特异性和准确性,尤其是对低运动水平的患者,对减少运动试验诊断的漏诊率具有重要意义. 相似文献
68.
通过对 5 0 0例经尿 11项试纸检查阴性的标本 ,沉渣镜检发现尚有 6 7例阳性 ,阳性率为 13.4 %。提示尿沉渣镜检 ,不失为泌尿系统疾病检查的必要手段不应忽视及偏废 相似文献
69.
70.
目的 观察奥曲肽对肝硬化大鼠门脉压力和细菌转位的影响.方法 皮下注射50%四氯化碳橄榄油溶液诱导大鼠肝硬化后,用不同剂量的奥曲肽皮下注射,随机分为A组:注射剂量20μg/kg,B组:注射剂量10μg/kg,C组:生理盐水,共7 d,治疗结束后在无菌条件下获取肠系膜淋巴结,肝、脾、空肠及回肠内容物作细菌培养,并用直接法测门脉压力.结果 奥曲肽能明显降低肝硬化大鼠门脉压力,但A组较B组明显增加肠道细菌增长和细菌转位.结论 大剂量奥曲肽能增加肝硬化肠道细菌过增长,可能增加细菌转位的发生. 相似文献