首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   793篇
  免费   46篇
  国内免费   41篇
耳鼻咽喉   1篇
儿科学   11篇
妇产科学   2篇
基础医学   60篇
口腔科学   2篇
临床医学   26篇
内科学   129篇
皮肤病学   6篇
神经病学   1篇
特种医学   10篇
外科学   40篇
综合类   85篇
预防医学   250篇
药学   130篇
中国医学   104篇
肿瘤学   23篇
  2024年   2篇
  2023年   6篇
  2022年   7篇
  2021年   51篇
  2020年   24篇
  2019年   18篇
  2018年   22篇
  2017年   32篇
  2016年   39篇
  2015年   47篇
  2014年   62篇
  2013年   93篇
  2012年   41篇
  2011年   46篇
  2010年   33篇
  2009年   29篇
  2008年   30篇
  2007年   31篇
  2006年   26篇
  2005年   24篇
  2004年   28篇
  2003年   16篇
  2002年   18篇
  2001年   12篇
  2000年   20篇
  1999年   9篇
  1998年   6篇
  1997年   9篇
  1996年   11篇
  1995年   10篇
  1994年   6篇
  1993年   4篇
  1992年   9篇
  1991年   11篇
  1990年   6篇
  1989年   10篇
  1988年   1篇
  1987年   9篇
  1986年   3篇
  1985年   8篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
  1977年   1篇
  1976年   2篇
  1975年   1篇
  1974年   2篇
排序方式: 共有880条查询结果,搜索用时 15 毫秒
1.
2.
目的探讨白芷酒炖前后对挥发性成分的影响。方法采用顶空固相微萃取技术(HS-SPME)结合气相色谱-质谱法(GC-MS)对白芷酒炖前后挥发性成分及其相对百分含量进行对比分析。结果从白芷生品中初步检测出53个峰,鉴定出36个成分;从白芷酒炖中检测出32个峰,鉴定出26个成分;与生品成分比较,酒炖白芷中有22种成分未测到,但新增了12种成分,表明酒炖白芷中的挥发性成分的组成和含量均发生了变化。结论白芷酒炖后由于受热及辅料黄酒的作用使挥发性成分的种类及含量发生了明显变化,并存在成分转化,本研究为白芷酒炖的炮制机理及其在都梁丸中应用的物质基础研究提供了科学依据。  相似文献   
3.
This study investigated the effect and mechanism of pre-germinated brown rice (PGBR) prevented hyperglycemia in C57BL/6J mice fed high-fat-diet (HFD). Normal six-week-old mice were randomly divided into three groups. Group 1 was fed standard-regular-diet (SRD) and group 2 was fed HFD for 16 weeks. In group 3, the mice were fed a HFD with its carbohydrate replaced with PGBR for 16 weeks. Comparing the SRD and HFD groups, we found the HFD group had higher blood pressure, higher concentrations of blood glucose and HbA1c. The HFD group had less protein expression of insulin receptor (IR), insulin receptor substrate-1 (IRS-1), phosphatidylinositol-3-kinase (PI3K), glucose transporter-4 (GLUT-4) and glucokinase (GCK) and greater expression of glucogen synthase kinase (GSK) in skeletal muscle. The HFD group also had less expression of IR, serine/threonine kinase PI3K-linked protein kinase B (Akt/PKB), AMP-activated protein kinase (AMPK), GCK and peroxisome proliferator-activated receptor γ (PPARγ) in liver. In the HFD + PGBR group, the PGBR could reverse the disorders of blood pressure, blood glucose, HbA1c and increase insulin concentration. PGBR increased the IR, IRS-1, PI3K, Akt, GLUT-1 and GLUT-4 proteins, and ameliorated AMPK, GCK, GSK and PPARγ proteins. Together, PGBR prevented HFD-induced hyperglycemia through improving insulin levels, insulin receptor, glucose transporters and enhancing glucose metabolism.  相似文献   
4.
Rice false smut is an emerging and economically-important rice disease caused by infection by the fungal pathogen Villosiclava virens. Ustiloxin B is an antimitotic cyclopeptide mycotoxin isolated from the rice false smut balls that formed in the pathogen-infected rice spikelets. A monoclonal antibody (mAb) designated as mAb 1B5A10 was generated with ustiloxin B—ovalbumin conjugate. A highly-sensitive and specific indirect competitive enzyme-linked immunosorbent assay (icELISA) was then developed. The median inhibitory concentration (IC50) of the icELISA was 18.0 ng/mL for the detection of ustiloxin B; the limit of detection was 0.6 ng/mL, and the calibration range was from 2.5 to 107.4 ng/mL. The LOD/LOQ values of the developed ELISA used for the determination of ustiloxin B in rice false smut balls and rice grains were 12/50 μg/g and 30/125 ng/g, respectively. The mAb 1B5A10 cross-reacted with ustiloxin A at 13.9% relative to ustiloxin B. Average recoveries of ustiloxin B ranged from 91.3% to 105.1% for rice false smut balls at spiking levels of 0.2 to 3.2 mg/g and from 92.6% to 103.5% for rice grains at spiking levels of 100 to 5000 ng/g. Comparison of ustiloxin B content in rice false smut balls and rice grains detected by both icELISA and high performance liquid chromatography (HPLC) demonstrated that the developed icELISA can be employed as an effective and accurate method for the detection of ustiloxin B in rice false smut balls, as well as rice food and feed samples.  相似文献   
5.
6.
目的:比较枳壳不同炮制品的燥性,考察其对功能性消化不良(FD)大鼠胃肠功能的影响。方法:以大鼠饮水量、排尿量、肾水通道蛋白3(AQP3)含量、血清环磷酸腺苷(c AMP)与血清环磷酸鸟苷(c GMP)比值为评价指标,观察不同剂量的枳壳生品、麸炒枳壳、蜜麸枳壳对健康大鼠水液代谢的影响;以胃黏膜损伤指数,血清肿瘤坏死因子-α(TNF-α),白细胞介素6(IL-6),IL-8含量为评价指标,观察不同剂量枳壳生品、麸炒枳壳、蜜麸枳壳对健康大鼠胃黏膜损伤的影响;以大鼠胃残留率和小肠推进率,血清胃动素(MTL),血管活性肠肽(VIP),降钙素基因相关肽(CGRP)含量为评价指标,观察不同剂量枳壳生品、麸炒枳壳、蜜麸枳壳对FD大鼠胃肠功能的影响。结果:在水液代谢方面,同等剂量给药组与空白组相比,差异性排序为枳壳生品麸炒枳壳蜜麸枳壳,且高剂量组低剂量组;在胃黏膜损伤方面,不同剂量枳壳生品、麸炒枳壳、蜜麸枳壳组各项指标与空白组比较均无显著性差异;在促胃肠动力方面,同等剂量给药组与模型组相比,差异性为麸炒枳壳枳壳生品蜜麸枳壳,且低剂量组高剂量组。结论:枳壳生品的燥性主要表现为对机体津液的损伤,且强度与剂量有关,对健康大鼠胃黏膜未见明显直接刺激。炮制后可在一定程度上缓和伤津之弊,且以蜜麸枳壳缓和作用最佳;枳壳生品和炮制品均可促进FD大鼠胃肠功能的恢复,麸炒枳壳治疗作用优于生品与蜜麸制品。  相似文献   
7.
8.

Objectives

To evaluate the formation of advanced oxidation protein products (AOPPs) in juvenile overweight/obesity and obesity-related disorders and to investigate the effect of weight reduction on AOPPs.

Design and methods

AOPPs were determined in 114 overweight/obese children and adolescents without/with insulin resistance and metabolic syndrome and compared with 53 lean controls. Measurements were repeated following weight reduction program (diet/exercise, bran-enriched diet/exercise, and diet/exercise plus metformin).

Results

Overweight/obese subjects had higher AOPPs than lean controls, more elevated in patients with co-occurring metabolic syndrome. AOPPs positively correlated with central obesity, triglycerides, lipid peroxidation and insulin, and negatively with glucose to insulin ratio. AOPPs decreased following obesity intervention and ΔAOPPs correlated with ΔBMI%. AOPPs reduction was more pronounced in subjects on bran-enriched diet. Baseline AOPPs were a better predictor of clinically significant weight reduction than BMI%.

Conclusions

Juvenile overweight/obesity was associated with AOPPs accumulation, more pronounced in metabolic syndrome. Body mass reduction decreased oxidative stress, with bran-enriched diet being more effective than diet/exercise alone.  相似文献   
9.
The present study compared the effects of three rice cultivars on postprandial glycemic control and appetite. A single-blind, randomized, crossover clinical trial was performed with 18 healthy subjects, nine males and nine females. Three treatments were administered at three separate study visits: commercially available conventional white rice (short grain), specialty high amylose white rice 1 (Dixiebelle), and specialty high amylose white rice 2 (Rondo). Postprandial capillary blood glucose, venous blood glucose and insulin measurements, and appetite visual analog scale (VAS) surveys were done over the course of two hours. The capillary blood glucose concentrations were significantly lower for Rondo compared to short grain rice at 30 min, and for Dixiebelle and Rondo compared to short grain rice at 45, 60, and 120 min. Capillary blood glucose area under the curve (AUC) was significantly lower for Dixiebelle and Rondo compared to short grain rice. Subjects were significantly more hungry at 30 min after Dixiebelle intake than Rondo intake, but there were no other significant effects in appetite ratings. The present study determined that intake of high amylose rice with resistant starch (RS) can attenuate postprandial blood glucose and insulin response in comparison to short grain rice.  相似文献   
10.
Structures of some bioactive phytochemicals in bran extract of the black rice cv. Riceberry that had demonstrated anti-cancer activity in leukemic cell line were investigated. After saponification with potassium hydroxide, separation of the unsaponified fraction by reversed-phase high performance liquid chromatography (HPLC) resulted in four sub-fractions that had a certain degree of anti-proliferation against a mouse leukemic cell line (WEHI-3 cell), this being IC50 at 24 h ranging between 2.80–467.11 μg/mL. Further purification of the bioactive substances contained in these four sub-fractions was performed by normal-phase HPLC. Structural characterization by gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance spectroscopy (NMR) resulted in, overall, the structures of seven phytosterols and four triterpenoids. Four phytosterols, 24-methylene-ergosta-5-en-3β-ol, 24-methylene-ergosta-7-en-3β-ol, fucosterol, and gramisterol, along with three triterpenoids, cycloeucalenol, lupenone, and lupeol, were found in the two sub-fractions that showed strong anti-leukemic cell proliferation (IC50 = 2.80 and 32.89 μg/mL). The other sterols and triterpenoids were campesterol, stigmasterol, β-sitosterol and 24-methylenecycloartanol. Together with the data from in vitro biological analysis, we suggest that gramisterol is a significant anti-cancer lead compound in Riceberry bran extract.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号