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   332篇
  免费   6篇
耳鼻咽喉   1篇
儿科学   55篇
基础医学   19篇
口腔科学   2篇
临床医学   28篇
内科学   74篇
皮肤病学   10篇
神经病学   31篇
特种医学   1篇
外科学   69篇
预防医学   5篇
眼科学   2篇
药学   22篇
肿瘤学   19篇
  2021年   1篇
  2016年   5篇
  2015年   5篇
  2014年   5篇
  2013年   2篇
  2012年   1篇
  2011年   4篇
  2010年   4篇
  2009年   3篇
  2008年   2篇
  2007年   7篇
  2006年   18篇
  2005年   11篇
  2004年   15篇
  2003年   11篇
  2002年   8篇
  2001年   6篇
  2000年   2篇
  1999年   14篇
  1998年   28篇
  1997年   23篇
  1996年   22篇
  1995年   24篇
  1994年   16篇
  1993年   20篇
  1992年   7篇
  1991年   3篇
  1990年   6篇
  1989年   3篇
  1988年   3篇
  1986年   5篇
  1985年   5篇
  1984年   5篇
  1983年   4篇
  1981年   3篇
  1980年   3篇
  1979年   6篇
  1978年   2篇
  1977年   3篇
  1976年   1篇
  1973年   1篇
  1972年   1篇
  1971年   1篇
  1968年   1篇
  1963年   1篇
  1959年   1篇
  1958年   4篇
  1957年   9篇
  1956年   1篇
  1955年   2篇
排序方式: 共有338条查询结果,搜索用时 15 毫秒
1.
2.
Neutrophilic dermatoses (ND), with or without accompanying myelodysplastic syndrome (MDS), were examined in terms of nuclear abnormality like pelgeroid anomaly of infiltrating cells into skin lesions. Six ND accompanying MDS showed 1.0 to 13.5% of such anomalous cells among infiltrating cells. In contrast, ND without accompanying myeloproliferative disorders rarely had such anomalous cells. Our findings suggest that pelgeroid-like anomalous cells infiltrating into ND are probably a good marker of underlying MDS.  相似文献   
3.
BACKGROUND: The value of serum prostate-specific antigen (PSA) screening was examined to detect prostate cancer in men receiving hemodialysis. METHODS: Forty-one male patients age 60-95 (median age, 70 years) receiving hemodialysis were investigated for PSA levels. We set the cut-off point at 4 ng/mL (the usual reference range). Digital rectal examination (DRE) and transrectal ultrasonography (TRUS) of the prostate were performed in patients whose PSA was more than 4 ng/mL and/or who expected further examination of the prostate. When prostate cancer was suspected, biopsy of the prostate was performed. In patients with prostate cancer, magnetic resonance imaging, computed tomography and bone scintigraphy were performed to diagnose the clinical stage. RESULTS: The mean serum level of PSA was 2.10 +/- 0.49 ng/mL. In this screening study, four of 41 men required further examinations for prostate cancer. Two of four refused further examinations. The other two were diagnosed with prostate cancer. The incidence of prostate cancer was at least 5% in our hemodialysis patients. One man, whose clinical stage was T2aN0M0, was treated with radical retropubic prostatectomy. Another man, whose clinical stage was T2bN0M0, was treated with luteinizing hormone-releasing hormone analogue. CONCLUSION: In our preliminary study, prostate cancer screening with PSA was useful for the early detection of prostate cancer in hemodialysis patients. If possible, DRE and TRUS should be performed in conjunction with PSA tests.  相似文献   
4.
In a patient with sustained ventricular tachycardia, we obtained two different paced QRS morphologies from a single pacing site. In one QRS morphology the stimulus to the QRS complex was long, 150 msec, and in the other it was 100 msec. At the paced cycle length of 600 msec and the stimulus output of 4 V, one QRS morphology with the stimulus to the onset of QRS activation (St-QRS) interval of 150 msec was observed. At the paced cycle length of 400 msec, the other QRS morphology with a St-QRS interval of 100 msec was observed alternatively with the former. At the paced cycle length of 353 msec or 316 msec, the latter with a shorter St-QRS interval was exclusively observed. When the stimulus output was increased from 4 to 10 V, keeping with the paced cycle length at 400 msec, the St-QRS interval was shortened from 100 to 80 msec. For the two QRS morphologies with two St-QRS intervals, two slowly conducting pathways would be responsible. The site of the block in the faster pathway must be located at the proximity of the pacing site and the conduction at a shorter paced cycle length would be explained by "supernormal conduction."  相似文献   
5.
Pharmacokinetk Analysis of Increased Toxicity of 2-sec-ButylphenylMethylcarbamate (BPMC) by Fenitrothion Pretreatment in Mice.TSUDA, S., MIYAOKA, T., IWASAKI, M., AND SHIRASU, Y. (1984).Fundam. Appl. Toxicol. 4, 724–730. The potentiating effectof O,O-dimethyl O-(3-methyl-4-nitrophenyl) phosphorothioate(fenitrothion) on the toxicity of 2-sec-butylphenyl methylcarbamate(BPMC) in male mice was analyzed pharmacokinetically. The animalspretreated by dietary administration of 1000 ppm fenitrothionfor 1 week (4.4% of the po LD50 daily) did not show toxic symptomsexcept for a slight decrease in body weight In the fenitrothion-pretreatedmice, toxicity of fenitrothion was not changed but a fivefoldpotentiation was observed in po and ip acute lethality and athreefold potentiation of iv lethality of BPMC. Toxic signsafter BPMC administration were similar regardless of fenitrothionpretreatment or of route of administration. Fenitrothion pretreatmentfollowed by BPMC administration (20 mg/kg po or 8 mg/kg iv,approximate LD5 in the pretreated mice) significantly increasedthe plasma BPMC concentration and the total area under the plasmaconcentration versus time curve (AUG0-. The pretreatment increasedthe oral AUC0-, more greatly than the iv AUC0-, (for po, 6.3-fold;for iv, 2.0-fold). The oral systemic availability of BPMC (fractionreaching systemic circulation) was increased by fenitrothiontreatment to 3.3-fold. These results suggest that a major causeof the potentiation may be the increase in amount of BPMC inthe systemic circulation.  相似文献   
6.
Posterior stabilization is a common surgical procedure, which aims for rigid stabilization by facet fusion. Facet non-union has a potential risk of the screw loosening and malalignment. Although some authors have reported the influencing factors about screw loosening in the lumbar spine, there are few reports about the risk factor contributing to the facet non-union in the cervical spine. In all, 22 patients (78 facets and 122 screws) with degenerative cervical kyphosis or spondylolisthesis who underwent decompression and lateral mass screw (LMS) fixation were analyzed. Age, gender, smoking, bone mineral density (BMD), the degree of facet decortication with bone packing, and screw loosening were investigated as risk factors contributing to the facet non-union at each segmental fused level. Facet fusion rate was 85.9% (67/78 facets) and the incidence of loosening was 4.9% (6/122 screws, 4 patients). Insufficient facet decortication with bone packing is a significant risk factor of facet non-union (p <0.05, odds ratio: 26.5). All six loosened screws were associated with bony non-union of the facet and were located in the uppermost or lowermost vertebrae. Comparing loosened screws and stable screws, the average maximal insertional screw torque (MIT) was 9.8 cNm and 39.5 cNm, respectively (p <0.05). Additionally, the length of the stable screws was significantly longer versus the loosened screws (p <0.05). Lower MIT and shorter screw length located near the ends of the lateral mass may predict loosening, which can lead to facet non-union. Sufficient facet decortication with bone packing is one of the important factors contributing to the facet fusion.  相似文献   
7.
We evaluated the effects of the seed saponins of Thea sinensisL. on alcohol absorption and metabolism in rats and mice. Anethanolic extract from the seeds of T. sinensis was orally administeredto the rats 1 hr before or 0.5 hr after administration of ethanol(2 g/kg), and the blood ethanol assayed 0.5, 1, 2, 3, and 4hr after ethanol administration. The ethanol level decreasedafter both pie- and post- administration of the extract. Theextract was further purified to obtain a saponin fraction whichwas orally administered to mice 1 hr before ethanol administration.Blood, liver, and stomach were obtained 0, 1, 3, and 6 hr afterethanol administration, and the ethanol, acetaldehyde, acetate,and acetone concentrations in each specimen were measured byhead space gas chromatography. The saponin fraction decreasedthe ethanol levels in the blood and liver but increased thatin the stomach five-fold over the control level, suggestinginhibition of alcohol absorption. The ethanol disappearancetime from the blood was shortened, suggesting the promotionof alcohol disappearance. The acetate and acetone levels wereunaffected. However, the acetaldehyde level decreased in theblood, liver, and stomach. The decreases in the ethanol andacetaldhyde levels in the liver suggested the protective effectsof the seed saponins on the liver. The saponins did not directlyinhibit hepalic alcohol dehydrogenase activity. The seed saponinsof T. sinensis seem to suppress alcohol absorption by slowinggastric emptying and by inhibiting absorption across the cellmembranes of the digestive tract.  相似文献   
8.
Combined Repeat Dose and Reproductive/Developmental ToxicityScreening Test (OECD): Familiarization Using Cyclophosphamide.TANAKA, S., KAWASHIMA, K., NAITO, K., USAMI, M., NAKADATE, M.,IMAIDA, K., TAKAHASHI, M., HAYASHI, Y., KUROKAWA, Y., AND TOBE,M. (1992A, Y., AND TOBE, M. (1992). Fundam. Appl. Toxicol. 18,89–95. A familiarization study was conducted on the "Combined RepeatDose and Reproductive/Developmental Toxicity Screening Test(ReproTox)" proposed by the OECD. Cyclophosphamide (CP) at dosesof 6.7, 4.5, 3, 2, and 0 mg/kg body wt was given daily by gavageto groups of 12 male and 12 female Sprague-Dawley rats. As aresult, anemia and leukopenia were evident in treated males.The absolute and relative thymus and spleen weights were decreasedin treated rats. Histopathologically, atrophy of the thymus,spleen, and bone marrow was observed. With respect to the reproductive/developmentaltoxicity, dose-dependent increases in postimplantation lossof fetuses and postnatal death were found in dams given CP.The body weight of pups treated with CP was significantly loweredin a dose-related manner. Thus the results demonstrated mostof the known toxicological properties of CP, except the adverseeffects on spermatogenesis and fertility. Therefore ReproToxcan be considered as a useful screening test for assessing repeatdose and reproductive/developmental toxicity of existing chemicalsof high production volume.  相似文献   
9.
Background and objective: Bronchiolitis obliterans (BO) has been reported to develop following ingestion of Sauropus androgynus (SA), a leafy shrub distributed in Southeast Asia. Little is known about direct effects of SA on airway resident cells or haematopoietic cells in vitro. Identification of the SA component responsible for the development of BO would be an important key to elucidate its mechanism. We sought to elucidate the direct effects of SA on airway resident cells or haematopoietic cells and identify the SA element responsible for the pathogenesis of BO. Methods: SA dry powder was partitioned into fractions by solvent extraction. Human and murine monocytic cells, epithelial cells and endothelial cells were cultured with SA solution or fractions eluted from SA. We also investigated the effect of SA in vivo using a murine BO syndrome (BOS) model. Results: The aqueous fraction of SA induced significant increases of inflammatory cytokine and chemokine production from monocytic lineage cells. This fraction also induced significant apoptosis of endothelial cells and enhanced intraluminal obstructive fibrosis in allogeneic trachea allograft in the murine BOS model. We found individual differences in tumour necrosis factor α (TNF‐α) production from monocytes of healthy controls stimulated by this aqueous fraction of SA, whereas it induced high‐level TNF‐α production from monocytes of patients with SA‐induced BO. Conclusions: These results suggest that an aqueous fraction of SA may be responsible for the pathogenesis of BO.  相似文献   
10.
BACKGROUND: We report our experience with Gas-less laparoscopy-assisted surgery (Gas-less LAS), hand-assisted laparoscopic surgery (HALS) and pure laparoscopic surgery (LS) for renal carcinoma and compare the characteristics and usefulness of these methods. METHODS: Seventeen, 14 and 16 patients were subjected to Gas-less LAS, HALS and LS, respectively. The study started with Gas-less LAS and then gradually shifted to HALS and LS. We evaluated the operative and postoperative parameters for each group. The learning curve effect was evaluated based on data from the first 10 cases of each group, which were operated on by the same surgeon and operation team. RESULTS: The learning curve of operation times in the LS group demonstrated that the operation time for this procedure is acceptable even in early-stage cases. Differences in mean operative time between the three surgical groups, excluding the conversion cases, were not statistically significant; however, there was a significant difference in blood loss volume between the groups (P 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