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   2045篇
  免费   103篇
  国内免费   12篇
耳鼻咽喉   69篇
儿科学   52篇
妇产科学   16篇
基础医学   318篇
口腔科学   26篇
临床医学   147篇
内科学   419篇
皮肤病学   149篇
神经病学   82篇
特种医学   82篇
外科学   334篇
综合类   7篇
预防医学   59篇
眼科学   23篇
药学   151篇
肿瘤学   226篇
  2022年   24篇
  2021年   29篇
  2020年   15篇
  2019年   32篇
  2018年   40篇
  2017年   33篇
  2016年   35篇
  2015年   27篇
  2014年   47篇
  2013年   59篇
  2012年   82篇
  2011年   100篇
  2010年   78篇
  2009年   49篇
  2008年   77篇
  2007年   96篇
  2006年   117篇
  2005年   100篇
  2004年   70篇
  2003年   90篇
  2002年   93篇
  2001年   59篇
  2000年   71篇
  1999年   79篇
  1998年   39篇
  1997年   22篇
  1996年   22篇
  1995年   17篇
  1994年   17篇
  1993年   21篇
  1992年   60篇
  1991年   44篇
  1990年   50篇
  1989年   37篇
  1988年   44篇
  1987年   27篇
  1986年   31篇
  1985年   27篇
  1984年   23篇
  1983年   23篇
  1981年   15篇
  1980年   13篇
  1979年   13篇
  1978年   10篇
  1975年   8篇
  1974年   11篇
  1973年   9篇
  1972年   11篇
  1968年   9篇
  1967年   8篇
排序方式: 共有2160条查询结果,搜索用时 15 毫秒
1.
2.
3.
Estramustine phosphate disodium (Estracyt) was used in the treatment of 38 patients with prostatic carcinoma for at least 1 year. Of these patients 37 patients were treated with Estracyt as primary treatment and 1 patient had been treated with another antiandrogenic therapy before the Estracyt treatment. Estracyt was given orally in a dose of 560 mg/day in divided oral doses. The clinical evaluation was done for the change of PAP, the relapse rate, the survival rate and the side effect. Among 22 cases which had shown abnormally high PAP values before the treatment started, the values decreased or normalized in 21 cases (95.5%) in the first year of administration of Estracyt. In 6 cases, however, the values increased again in the second year or later. Relapse was observed in 10 (26.3%) out of 38 cases. Relapse rate was 2.6%, 51.7%, and 51.7%, at the first, third, and fifth year, respectively. Survival rate was 97.4% at the first year, 88.5% at the third year, and 68.8% at the fifth year for the follow-up study. Side effects were observed in 14 (36.8%) out of 38 cases. The main side effect was gynecomastia. Gastro-intestinal disturbance and edema were also observed. However, there were only 2 cases (5.2%) in which administration of Estracyt had to be discontinued.  相似文献   
4.
Since the prevalence and clinical characteristics of young-onset hypertension are still to be elucidated, we performed targeted-screening at an annual university health check-up for two consecutive years. Out of 16,464 subjects in 2003 and 17,032 in 2004 that were aged less than 30 years, 22 and 26 students (all males) exhibited high blood pressure (BP), respectively, on three occasions during casual BP measurements at the Tohoku University Health Center (systolic and diastolic BP of 140 and/or 90 mmHg or greater, respectively). These students were asked to measure their BP at home, and 9 subjects in total were diagnosed as having essential hypertension (EH). The remaining students were diagnosed as having white coat hypertension (WCH). In 8 out of 9 EH students, their father and/or mother had also been treated with antihypertensive medication. Adjustment by attendance ratio for each BP measurement suggested that the incidence of EH was around 0.1% and that of hypertension (EH and WCH) was around 0.5% in university students aged less than 25 years, since most of the subjects and hypertensive students were between 18 and 24 years old. Body mass index of the EH, which was more than 25 kg/m2 (overweight), was significantly higher than that with WCH. In conclusion, the combination of repeated casual BP measurements and home BP effectively identified young-onset EH. The clinical parameters indicated that male gender, genetic background, and excessive weight were risk factors for young-onset hypertension.  相似文献   
5.
We investigated prolidase activity in samples derived from wound fluid as well as blister fluid. Prolidase activity was elevated in fluid samples collected from wounds over the levels in sera collected from patients with chronic wounds (P<0.05). Prolidase activity was also present in samples taken from blister diseases. However, prolidase activity in blister fluid was not higher than that in sera collected from patients with blister diseases. Our results indicate that prolidase may play a role in wound healing.  相似文献   
6.
  • 1) The prolidase (Pd) and prolinase (Pn) activities of cultured skin fibroblasts derived from two prolidase-deficient sisters, the elder with typical clinical manifestations [symptom (+)] and the younger with only slight clinical manifestations [symptom (–)] were examined biochemically. Pd activity against several substrates other than Gly-Pro were present to some degree in both sisters. There were no detectable differences in Pd activity between the symptom (+) patient and the symptom (–) sister. Pn activity seemed to be increased in both. The lower Pn activity found against Pro-Gly as compared with those against other substrates indicates that Pro-Gly, which has been used for Pn assays in most previous reports, may not be the best substrate for this test. Pd derived from control fibroblasts was activated by Mn2+ against all substrates tested in this experiment. Cu2+, Hg2+, Cd2+ and Zn2+ remarkably inhibited enzyme activity, Co2+ slightly inhibited it, and neither Mg2+ nor Fe2+ had any remarkable effect. The Pd derived from the prolidase-deficient patients was also activated by Mn2+. This Pd seemed to be more inhibited by Co2+ than was the control. However, we found no remarkable differences between the two patients.
  • 2) We also studied Pd and Pn activities in rat skin and blood during wound healing. Pd and Pn activities adjacent to the wound increased in parallel with fibroblast proliferation. Pd activity was also detected in an extract of newborn mouse epidermis.
  相似文献   
7.
We previously found frequent loss of heterozygosity at 12q21 and 12q22-q23.1 in primary pancreatic cancers, and the DUSP6/MKP-3 gene residing in this region at 12q22 lost its expression in the great majority of pancreatic cancer cell lines. The DUSP6/MKP-3 protein is a dual-specificity phosphatase that dephosphorylates the active form of ERK, making a feedback loop to control ERK activity. Gain-of-function mutations of KRAS2 occur in the great majority of pancreatic cancer cells, and loss of expression of DUSP6/MKP-3 may synergistically promote constitutive activation of ERK and uncontrolled cell growth. To study loss of the feedback pathway and its impact on pancreatic cancer cell growth, we first investigated the expression of DUSP6/MKP-3 in primary pancreatic cancer tissues immunohistochemically; we found up-regulation in mildly as well as severely dysplastic/in situ carcinoma cells and down-regulation in invasive carcinoma, especially in the poorly differentiated type. Adenovirus-mediated reintroduction of DUSP6/MKP-3 into cultured pancreatic cancer cells induced strong expression of recombinant DUSP6/MKP-3 and reduction of phosphorylated ERK in a dose-dependent manner based on the multiplicity of infection and resulted in suppression of cell growth. Moreover, analyses by flow cytometry and immunocytochemistry revealed that the exogenous expression of DUSP6/MKP-3 induced apoptosis. These results show that DUSP6 exerts apparent tumor-suppressive effects in vitro and suggest that DUSP6 is a strong candidate tumor suppressor gene at 12q22 locus.  相似文献   
8.
Prostate cancer is a major cause of cancer death among elderly men in America, Europe, and Japan. However, the molecular mechanism of carcinogenesis is not yet well characterized. Frequent loss of heterozygosity (LOH) on chromosome 10q was reported in prostate cancer, and a candidate tumor suppressor gene, PTEN, was isolated on chromosome band 10q23.3. To investigate the genetic alterations of PTEN, we examined 45 primary prostate cancer specimens. LOH at the PTEN locus was observed in two (11.1%) of 18 tumors. However, no mutations were observed in any of the primary prostate cancers. These data suggest that mutation of the PTEN gene does not play a major role in prostate carcinogenesis of Japanese patients. Received: February 6, 1998 / Accepted: July, 3, 1998  相似文献   
9.
Defensins are cationic antimicrobial peptides with a broad spectrum. Recently human beta-defensin 2 (hBD-2) has been isolated from psoriatic skin; however, its exact localization and fate have not been fully understood. We studied the distribution pattern of hBD-2 in skin tissues of psoriasis and other inflammatory skin diseases. In the upper spinous and granular layer of psoriasis vulgaris hBD-2 was present in the cytoplasm. In the horny layer the positive signals were in a basket-weave pattern, indicating possible accumulation of hBD-2 in the intercellular space. The similar pattern of hBD-2 distribution was observed in the lesions of nummular eczema and atopic dermatitis. hBD-2 was not detected in the section of normal elbow and knee skin. When isolated psoriatic scales were stained, hBD-2 was detected in a wrapping paper-like distribution pattern surrounding the corneocytes. In horny layer of psoriatic skin hBD-2 was closely associated or colocalized with elafin, which is known to be in extracellular space, as demonstrated by double staining. Western blot analysis using cultured human keratinocytes detected hBD-2 with an expected size in the conditioned medium and in the cell lysates when stimulated with 5% FCS or IL-alpha. These results indicate that hBD-2 was synthesized and remained in cytoplasm in the upper spinous and granular layer, and then secreted into intercellular space in the horny layer. This dynamic change in hBD-2 distribution in epidermis is certainly relevant to function as an innate host defense mechanism against invading micro-organisms.  相似文献   
10.
Pulmonary fibrosis is the result of abnormal processes of repair that occur after lung injury. Transforming growth factor (TGF)-beta is a key molecule in the progression of pulmonary fibrosis. Although clinical use of interferon (IFN)-beta did not improve survival in patients with idiopathic pulmonary fibrosis, because some preclinical studies have suggested that IFN-beta is a potent inhibitor of fibrogenesis, beneficial effects of IFN-beta have been expected. We therefore attempted to determine effects of IFN-beta and investigated the mechanism of action of IFN-beta in bleomycin-induced pulmonary fibrosis. Bleomycin at Day 0 and IFN-beta for 4 wk were administered intravenously to ICR mice. At 28 d after bleomycin injection, histologic and chemical analysis was performed for evaluation of effects of IFN-beta. Tissue distribution and amounts of TGF-beta1 and thrombospondin (TSP)-1/2 were analyzed. IFN-beta attenuated prolylhydroxylase activity, resulting in inhibition of pulmonary fibrosis. Bleomycin-induced increase in TGF-beta1 in epithelial cells and extracellular matrix was attenuated by IFN-beta. TSP-1/2 was limited in platelets of control mice, but was present in foamy cells in fibrotic regions induced by bleomycin. These findings suggest that the antifibrotic effect of IFN-beta is inhibition of TGF-beta and its activation via decrease in TSP-1/2 in lung tissue and change in location of TSP-1/2 from platelets to foamy cells.  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