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   858篇
  免费   58篇
  国内免费   2篇
耳鼻咽喉   13篇
儿科学   20篇
妇产科学   4篇
基础医学   164篇
口腔科学   28篇
临床医学   78篇
内科学   211篇
皮肤病学   3篇
神经病学   66篇
特种医学   45篇
外科学   76篇
综合类   5篇
预防医学   23篇
眼科学   19篇
药学   95篇
肿瘤学   68篇
  2023年   4篇
  2022年   10篇
  2021年   16篇
  2020年   6篇
  2019年   11篇
  2018年   9篇
  2017年   12篇
  2016年   11篇
  2015年   14篇
  2014年   30篇
  2013年   25篇
  2012年   50篇
  2011年   55篇
  2010年   28篇
  2009年   24篇
  2008年   33篇
  2007年   44篇
  2006年   49篇
  2005年   57篇
  2004年   32篇
  2003年   36篇
  2002年   29篇
  2001年   39篇
  2000年   27篇
  1999年   20篇
  1998年   9篇
  1997年   7篇
  1996年   5篇
  1995年   10篇
  1993年   4篇
  1992年   22篇
  1991年   29篇
  1990年   17篇
  1989年   15篇
  1988年   11篇
  1987年   7篇
  1986年   9篇
  1985年   6篇
  1984年   5篇
  1982年   6篇
  1978年   4篇
  1977年   5篇
  1974年   4篇
  1972年   3篇
  1971年   12篇
  1970年   6篇
  1969年   5篇
  1968年   5篇
  1967年   9篇
  1966年   9篇
排序方式: 共有918条查询结果,搜索用时 15 毫秒
1.
On the basis of data showing a bimodal distribution of values for extracellular pH (pHe), and a discontinuous delta PCO2/delta lactate relationship, Kraig et al. (1986) proposed that H+ is grossly compartmentalized between neurons and glia in the ischemic brain. We measured delta pHe during ischemia, varying ischemic lactate contents between 9 and 38 mmol kg-1. No bimodal distribution was found, but delta pHe varied linearly with lactate content. Because we have also failed to record a discontinuous delta PCO2/delta lactate relationship, we conclude that major compartmentation of H+ does not occur during ischemia.  相似文献   
2.
A series of 8 rat and 16 mouse invasive bladder carcinomas were investigated for the presence of silverstained nucleolar organizer regions (AgNORs) to clarify whether this parameter is applicable to the estimation of their invasive character. With regard to number of AgNORs per cell, neither rat nor mouse carcinomas showed any difference between invasive and noninvasive sites within the same tumor. However, the frequency of cancer cells bearing bizarre dots, irregular in size and shape, was significantly higher at sites of actual invasion. Quantitative data generated using an image analyzer revealed significantly lower values for NOR roundness and significantly larger NOR size in invasive sites than in noninvasive sites in all groups. Double staining for the proliferation marker proliferating cell nuclear antigen (PCNA) and AgNORs was performed on eight rat carcinomas and a close correlation between the two was confirmed. Thus the number of AgNORs in PCNA-positive cells was significantly greater than in PCNA-negative cells. Furthermore, a particularly strong correlation was observed for incidences of PCNA-positive cells and bizarre dots (P<0.01). The quantitative data also demonstrated significant differences in size and shape of dots. It is concluded that AgNORs have diagnostic value for the invasive character of bladder carcinomas.  相似文献   
3.
4.
The current study investigates the effect of megestrol acetate, a synthetic progestin, on the activity of interleukin-1. Murine thymocytes were suspended in vitro and stimulated with varying concentrations of interleukin-1. [3H]Thymidine uptake was observed as an index of thymocyte proliferation. A dose-dependent increase in [3H]thymidine uptake was observed with increasing concentrations of interleukin-1. When megestrol acetate was added to the solution, a marked suppressive effect was observed. Higher doses of megestrol acetate had a greater suppressive effect on thymocyte proliferation. Additional investigation is required to further delineate the potential systemic effects of megestrol acetate.  相似文献   
5.
A case of repeated episodes of hypoventilatory respiratory failure accompanied with primary hypothyroidism was reported. A 76-year-old woman was admitted to our hospital due to both disturbance of consciousness and respiratory failure. A diagnosis of primary hypothyroidism complicated with hypoventilatory respiratory failure deterioration due to respiratory infection was made. Supplemental therapy of thyroid hormones improved her general condition, but respiratory failure recurred after interruption of a replacement drug. Cases of unexplained respiratory failure should be differentiated from respiratory failure induced by hypothyroidism.  相似文献   
6.
The amount of lactate formed during ischemia determines the rise in tissue PCO2 (PtCO2). Conflicting results exist on the relationship between lactate and PtCO2. The objective of this study was to settle this issue. We varied the preischemic plasma glucose concentration of normo- and hypercapnic rats, assessed tissue lactate and total CO2 contents, and determined the PCO2/lactate relationship over the lactate range 2-40 mmol kg-1. The results showed that whatever the equilibration time, the PCO2/lactate relationship was linear. The results obtained could be reproduced by a theoretical buffer system that mimics the buffering behavior of intracellular fluid. Our results bear on the question of whether compartmentation of H+ occurs during ischemia, with glial cells becoming more acid than neurons. A discontinuous PCO2/lactate relationship, with a constant PCO2 above a certain lactate content, would support this contention. Since our results demonstrate a linear relationship between lactate and PCO2 over the lactate range 2-40 mmol kg-1, they considerably weaken any argument for gross compartmentation of H+.  相似文献   
7.
Crystalline lens changes of 17 cases of eye undergoing simple vitrectomy were observed from the post-operative 1st to 21st month. Changes in the crystalline lenses were detected through a slitlamp microscope or by methods of image analysis, the Opacity Lensmeter and the laser scattering spectroscopy. Increases of the scattering light intensity of the anterior and posterior deep cortical layers were observed from the early post-operative stage in 9 cases. Seven cases progressed to nuclear opacification during the observation period, however, one case showed no nuclear changes even at the 12 post-operative month. No relationships were observed between the early cortical changes and surgical invasion, patient age, or cause of vitreous opacification. Quantitative evaluation by image analysis revealed early post-operative crystalline lens changes in cases undergoing vitreous surgery.  相似文献   
8.
A 36 year old woman was admitted to our department because of a chest X-ray which showed multiple developing shadows. She underwent bilateral exploratory thoracotomies and a total 5 tumors were resected and pathologically diagnosed as benign metastasizing leiomyoma, the largest of which was positive for the progesterone receptor and negative for the estrogen receptor. A histogram of this tumor using a flow cytometer showed a diploid pattern and 4.6 percent of the S phase which was not more than that of a leiomyoma of the uterus from another patient. Two months later, she underwent a hysterectomy and bilateral salpingo-oophorectomy for treatment of the positive progesterone receptor in the pulmonary lesions. The resected uterine myoma and normal myometrium showed positive estrogen and progesterone receptors. For the subsequent 28 months she has been free of any further symptoms. Benign metastasizing leiomyoma of the uterus is a rare disease and very interesting because of its histological benignity and hormonal dependency. However, according to the literature, it is often confused in entity due to the fact that normal lung tissue also possesses hormone receptors. Considering our data on hormone receptors, it is rational to think that multiple leiomyomatous lesions in the lung should only be diagnosed as benign metastasizing leiomyomas when they possess positive estrogen and progesterone receptors.  相似文献   
9.
A detailed toxicity analysis was performed on the top minnow utilizing the stick‐enzyme immunoassay (S‐EIA), the mouse bioassay, the guinea pig atrium assay and fluorometric HPLC. The S‐EIA test indicated 96% of the samples tested contained polyether toxins. Mice injected with acetone extractions from top minnow displayed symptoms of toxicity while the guinea pig atrium assay demonstrated the presence of a polar, Na+ channel inhibitor.  相似文献   
10.
The distributions of radioactivity were examined by whole body autoradiography and liquid scintillation spectrophotometry in male ddY mice following oral administration of tritium-labelled Irgasan® DP300 (2,4,4-trichloro-2-hydroxydiphenyl ether) (I) and its three chlorinated derivatives; 2,3,4,4-tetrachloro-2-hydroxydiphenyl ether (II), 2,4,4,5-tetrachloro-2-hydroxydiphenyl ether (III) and 2,3,4,4,5-pentachloro-2-hydroxydiphenyl ether (IV). The autoradiograms at 6 or 24 hr showed that the radioactivity distributed in the gall, liver, lung, heart, and kidneys. Among these tissues the radioactivity was most concentrated in the gall, suggesting the enterohepatic circulation of these compounds. A much higher level of radioactivity in each tissue was observed in mice receiving [3H]-III than the other compounds tested. Most of the radioactivity disappeared from each tissue in 24 hr due to [3H]-Irgasan DP300, [3H]-II or [3H]-IV, but in 96 hr it was due to [3H]-III.The cumulative radioactivity excreted in urine after administration of these compounds was in the order of [3H]-Irgasan DP300, [3H]-II, [3H]-IV and [3H]-III while that in feces was in the order of [3H]-IV, [3H]-III, [3H]-II and [3H]-Irgasan DP300,This work was presented at the 106th Annual Meeting of the Pharmaceutical Society of Japan (1986).  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