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   1024篇
  免费   64篇
  国内免费   4篇
耳鼻咽喉   32篇
儿科学   23篇
妇产科学   9篇
基础医学   99篇
口腔科学   11篇
临床医学   107篇
内科学   377篇
皮肤病学   13篇
神经病学   66篇
特种医学   35篇
外科学   150篇
综合类   5篇
预防医学   17篇
眼科学   15篇
药学   58篇
中国医学   3篇
肿瘤学   72篇
  2021年   21篇
  2020年   9篇
  2019年   13篇
  2018年   22篇
  2017年   20篇
  2016年   22篇
  2015年   17篇
  2014年   22篇
  2013年   27篇
  2012年   42篇
  2011年   59篇
  2010年   26篇
  2009年   33篇
  2008年   47篇
  2007年   53篇
  2006年   42篇
  2005年   54篇
  2004年   41篇
  2003年   39篇
  2002年   52篇
  2001年   36篇
  2000年   54篇
  1999年   58篇
  1998年   9篇
  1997年   6篇
  1996年   7篇
  1995年   5篇
  1994年   9篇
  1993年   5篇
  1992年   11篇
  1991年   21篇
  1990年   9篇
  1989年   16篇
  1988年   11篇
  1987年   14篇
  1986年   8篇
  1985年   18篇
  1984年   9篇
  1983年   11篇
  1979年   10篇
  1978年   7篇
  1977年   6篇
  1976年   6篇
  1974年   9篇
  1973年   9篇
  1972年   13篇
  1971年   5篇
  1970年   9篇
  1969年   9篇
  1968年   5篇
排序方式: 共有1092条查询结果,搜索用时 15 毫秒
1.
The purpose of this study was to evaluate the quantitative changes in tooth mobility before and after periodontal surgery using a tooth mobility tester. The tester was so designed as to be able to measure the cycle of sympathetic vibrations produced when a tooth was tapped with a impact hammer. Initially the degrees of tooth mobility, which were clinically classified from 0 to 3, were observed and the mode of mobility was assessed by the tester. Then, we examined the changes of tooth mobility after flap surgery. The following is a summary of findings.
1)  The coefficient of change in measurements had a tendency to decrease at the buccal site and the cervical site.
2)  At 1 week after flap surgery, the degree of tooth mobility was increased significantly.
3)  At the 6th week after surgery, tooth mobility had returned to the preoperative level.
4)  At 6 months after surgery, the mobility was decreased significantly compared to immediatery after surgery.
5)  The extent of bone absorption, probing pocket depth and clinical attachment level did not influence the postoperative changes of tooth mobility.
  相似文献   
2.
3.
The inhibitory effects of hinokitiol (beta-thujaplicin) on Chlamydia trachomatis D/UW-3/Cx were shown by MIC, minimum lethal concentration (MLC), and preinoculation minimal microbicidal concentration assays using HeLa 229 cells. The MIC and the MLC were both 32 microg/ml. Further evaluation of hinokitiol as a topical agent against C. trachomatis is warranted.  相似文献   
4.
The administration of doxycycline prior to bleomycin in mice attenuated pulmonary fibrosis. Bronchoalveolar neutrophil influx and gelatinase activity, but not caseinolytic activity, were attenuated by doxycycline. Established fibrosis was not affected by doxycycline. Thus, doxycycline might be useful for slowing down pulmonary fibrosis by biological activity other than antibacterial activity.  相似文献   
5.
We compared pharmacologically-perturbed hemodynamic parameters (cerebral blood volume; CBV, and flow; CBF) by acetazolamide administration in six healthy human subjects studied with positron emission tomography (PET) and near-infrared (NIR) time-resolved spectroscopy (TRS) simultaneously to investigate whether NIR-TRS could measure in vivo hemodynamics in the brain tissue quantitatively. Simultaneously with the PET measurements, TRS measurements were performed at the forehead with four different optode spacing from 2 cm to 5 cm. Total hemoglobin and oxygen saturation (SO2) measured by TRS significantly increased after administration of acetazolamide at any optode spacing in all subjects. In PET study, CBV and CBF were estimated in the following three volumes of interest (VOIs) determined on magnetic resonance images, VOI1: scalp and skull, VOI2: gray matter region, VOI3: gray and white matter regions. Acetazolamide treatment elevated CBF and CBV significantly in VOI2 and VOI3 but VOI1. TRS-derived CBV was more strongly correlated with PET-derived counterpart in VOI2 and VOI3 when the optode spacing was above 4 cm, although optical signal from cerebral tissue could be caught with any optode spacing. As to increase of the CBV, 4 cm of optode spacing correlated best with VOI2. To support the result of TRS-PET experiment, we also estimated the contribution ratios of intracerebral tissue to observed absorption change based on diffusion theory. The contribution ratios at 4 cm were estimated as follows: 761 nm: 50%, 791 nm: 72%, 836 nm: 70%. These results demonstrated that NIR-TRS with 4 cm of optode spacing could measure cerebral hemodynamic responses optimally and quantitatively.  相似文献   
6.
The release of oxygen-derived free radicals has been implicated in endotoxin-mediated hepatic injury. The effect of hepatic lipid peroxidation on tissue energy reserves in the livers of normal and cirrhotic rats was studied following administraton ofE. coli endotoxin. Before endotoxin injection, the basal hepatic energy charge was lower and levels of hepatic malondialdehyde (MDA) and total glutathione (GSH) higher in cirrhotic rats than in normal rats. Virtually identical levels of blood endotoxin were obtained in the two groups 24h after injection of LD50 doses of endotoxin (20 mg/kg and 1 mg/kg in normal and cirrhotic rats, respectively). Hepatic energy charge, tissue blood flow, GSH and glutathione peroxidase (GPX) were consistently or transiently decreased up to 24h after the injection of endotoxin in both normal and cirrhotic rats. MDA, significantly increased in normal rats 1 h after injection of endotoxin, returned to normal levels 3–12 h after endotoxin administration, but was again elevated at 24 h. Cirrhotic rats did not show any significant change in MDA following endotoxin injection. In normal rats, endotoxin appears to trigger the liberation of free radicals accelerating depletion of hepatic energy reserves, over and above the effect of decreased hepatic blood flow. In contrast, increased lipid peroxidation was not detected in cirrhotic rats despite GSH and GPX consumption during endotoxemia (indicating oxygen radical generation). Cirrhotic livers were apparently protected against oxygen radical injury by higher levels of endogenous GSH and GPX. Reduced hepatic blood flow may be mainly responsible for the alteration in energy metabolism of the cirrhotic liver.  相似文献   
7.

Purpose

To evaluate the postoperative outcomes of cataract eyes complicated with coexisting ocular pathologies that underwent implantation of a refractive multifocal intraocular lens (MIOL) with a surface-embedded near section.

Methods

LENTIS MPlus (Oculentis GmbH) refractive MIOLs were implanted in 15 eyes with ocular pathologies other than cataract (ie, six high-myopia eyes with an axial length longer than 28 mm, two fundus albipunctatus eyes, two branch retinal-vein occlusion eyes, four glaucoma eyes (one with high myopia), and two keratoconus eyes). Uncorrected or corrected distance and near visual acuity (VA) (UDVA, UNVA, CDVA, and CNVA), contrast sensitivity, and defocus curve were measured at 1 day and 6 months postoperatively, and each patient completed a 6-month postoperative questionnaire regarding vision quality and eyeglass use.

Results

Thirteen eyes (87%) registered 0 or better in CDVA and 12 eyes (73%) registered better than 0 in CNVA. Contrast sensitivity in the eyes of all patients was comparable to that of normal healthy subjects. No patient required eyeglasses for distance vision, but three patients (20%) required them for near vision. No patient reported poor or very poor vision quality.

Conclusion

With careful case selection, sectorial refractive MIOL implantation is effective for treating cataract eyes complicated with ocular pathologies.  相似文献   
8.
9.
Resistant maltodextrin Fibersol-2 is a soluble and fermentable dietary fiber that is Generally Recognized As Safe (GRAS) in the United States. We tested whether Fibersol-2 contains anti-tumor activity. Human colorectal cancer cell line, HCT116, and its isogenic cells were treated with FIbersol-2. Tumor growth and tumorigenesis were studied in vitro and in vivo. Apoptotic pathway and generation of reactive oxygen species (ROS) were investigated. We discovered that Fibersol-2 significantly inhibits tumor growth of HCT116 cells by inducing apoptosis. Fibersol-2 strongly induces mitochondrial ROS and Bax-dependent cleavage of caspase 3 and 9, which is shown by isogenic HCT116 variants. Fibersol-2 induces phosphorylation of Akt, mTOR in parental HCT116 cells, but not in HCT116 deficient for Bax or p53. It prevents growth of tumor xenograft without any apparent signs of toxicity in vivo. These results identify Fibersol-2 as a mechanism-based dietary supplement agent that could prevent colorectal cancer development.  相似文献   
10.
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