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   2049篇
  免费   117篇
  国内免费   10篇
耳鼻咽喉   26篇
儿科学   43篇
妇产科学   11篇
基础医学   291篇
口腔科学   87篇
临床医学   153篇
内科学   457篇
皮肤病学   12篇
神经病学   111篇
特种医学   104篇
外科学   312篇
综合类   5篇
现状与发展   1篇
预防医学   82篇
眼科学   8篇
药学   175篇
中国医学   2篇
肿瘤学   296篇
  2024年   4篇
  2023年   27篇
  2022年   62篇
  2021年   87篇
  2020年   45篇
  2019年   70篇
  2018年   66篇
  2017年   46篇
  2016年   79篇
  2015年   93篇
  2014年   74篇
  2013年   76篇
  2012年   116篇
  2011年   161篇
  2010年   78篇
  2009年   56篇
  2008年   99篇
  2007年   100篇
  2006年   121篇
  2005年   111篇
  2004年   100篇
  2003年   114篇
  2002年   111篇
  2001年   13篇
  2000年   19篇
  1999年   23篇
  1998年   20篇
  1997年   13篇
  1996年   14篇
  1995年   9篇
  1994年   14篇
  1993年   13篇
  1992年   6篇
  1991年   12篇
  1990年   12篇
  1989年   13篇
  1988年   9篇
  1987年   12篇
  1986年   6篇
  1985年   8篇
  1984年   10篇
  1983年   6篇
  1981年   11篇
  1980年   8篇
  1979年   2篇
  1978年   2篇
  1977年   3篇
  1976年   5篇
  1974年   6篇
  1973年   6篇
排序方式: 共有2176条查询结果,搜索用时 312 毫秒
81.
82.
The prognosis of follicular lymphoma (FL) is significantly associated with host immunity and tumor microenvironment. Lymphopenia has been identified as a negative prognostic factor for FL. The association between monocytosis and progression-free survival (PFS) in FL remains controversial. It is unknown whether the ratio of peripheral blood absolute lymphocyte count to absolute monocyte count (ALC/AMC) at diagnosis is associated with FL prognosis. We studied 99 consecutive patients with FL who were treated with rituximab-containing chemotherapy at Kitano Hospital or Kyoto University Hospital between 2000 and 2012. We analyzed individual variables associated with the ALC/AMC ratio before treatment, as well as known prognostic factors of FL, and found that an ALC/AMC ratio of 4.7 was the best cut-off value for PFS. Kaplan–Meier analysis showed that a decreased ALC/AMC ratio was associated with inferior PFS (P = 0.022). Multivariate analysis showed that a decreased ALC/AMC ratio was a significant poor prognostic factor independent of other variables (hazard ratio, 2.714; 95 % confidence interval, 1.060–6.948; P = 0.037). The ALC/AMC ratio before treatment may be a significant prognostic factor predicting PFS of FL.  相似文献   
83.
Volumetric-modulated arc therapy (VMAT) is a widespread intensity-modulated radiation therapy (IMRT) method, however, VMAT requires adaptation of the radiation treatment planning system (RTPS) and linear accelerator (linac); these upgrades are quite expensive. The Smart Arc of Pinnacle3 (Philips), which is the software used in VMAT calculations, can select constant dose rate (CDR) mode. This approach has a low initial cost because the linac upgrade is not required. The objective of this study was to clarify the utility of CDR mode for prostate IMRT. Pinnacle3 and Clinac 21EX linac (Varian, 10 MV X-rays) were used for planning. The plans were created for 28 patients using a fixed multi-field IMRT (f-IMRT), VMAT and CDR techniques. The dose distribution results were classified into three groups: optimal, suboptimal and reject. For the f-IMRT, VMAT and CDR results, 25, 26 and 21 patients were classified as ‘optimal’, respectively. Our results show a significant reduction in the achievement rate of ‘optimal’ for a CDR when the bladder volume is <100 cm3. The total numbers of monitoring units (MUs) (average ± 1σ) were 469 ± 53, 357 ± 35 and 365 ± 33; the average optimization times were ∼50 min, 2 h and 2 h 40 min, and the irradiation times were ∼280 s, 60 s and 110 s, respectively. CDR can reduce the total MUs and irradiation time compared with f-IMRT, and CDR has a lower initial cost compared with VMAT. Thus, for institutions that do not currently perform VMAT, CDR is a useful option. Additionally, in the context of patient identification, bladder volume may be useful.  相似文献   
84.
The purpose of this study was to report the outcomes of high-dose-rate (HDR) brachytherapy and hypofractionated external beam radiotherapy (EBRT) combined with long-term androgen deprivation therapy (ADT) for National Comprehensive Cancer Network (NCCN) criteria-defined high-risk (HR) and very high-risk (VHR) prostate cancer. Data from 178 HR (n = 96, 54%) and VHR (n = 82, 46%) prostate cancer patients who underwent 192Ir-HDR brachytherapy and hypofractionated EBRT with long-term ADT between 2003 and 2008 were retrospectively analyzed. The mean dose to 90% of the planning target volume was 6.3 Gy/fraction of HDR brachytherapy. After five fractions of HDR treatment, EBRT with 10 fractions of 3 Gy was administered. All patients initially underwent ≥6 months of neoadjuvant ADT, and adjuvant ADT was continued for 36 months after EBRT. The median follow-up was 61 months (range, 25–94 months) from the start of radiotherapy. The 5-year biochemical non-evidence of disease, freedom from clinical failure and overall survival rates were 90.6% (HR, 97.8%; VHR, 81.9%), 95.2% (HR, 97.7%; VHR, 92.1%), and 96.9% (HR, 100%; VHR, 93.3%), respectively. The highest Radiation Therapy Oncology Group-defined late genitourinary toxicities were Grade 2 in 7.3% of patients and Grade 3 in 9.6%. The highest late gastrointestinal toxicities were Grade 2 in 2.8% of patients and Grade 3 in 0%. Although the 5-year outcome of this tri-modality approach seems favorable, further follow-up is necessary to validate clinical and survival advantages of this intensive approach compared with the standard EBRT approach.  相似文献   
85.
An 81‐year‐old man was referred to our hospital because gastric cancer was detected on screening esophagogastroduodenoscopy. Surgical resection of the tumor was performed. It was 25 × 20 mm in size and swollen lymph nodes were present nearby. Lymphadenectomy was also performed. Histopathologically, the tumor reached the proper muscle layer via venous invasion. There were three components that constituted the tumor, that is, 40% of mass was invasive micropapillary carcinoma (IMPC), 40% was papillary adenocarcinoma and 20% tubular adenocarcinoma. Vascular invasion was prominent. Immunohistochemistry revealed that the tumor showed an entirely intestinal mucin phenotype, being positive only for CD10 and negative for MUC2, MUC5AC, and MUC6. HER2 staining score ranged from 2+ to 3+, depending on the components described above. HER2 gene amplification was present in all the components according to dual‐color in situ hybridization. The metastatic lymph nodes were similar to the primary site in morphology and immunohistochemistry, but HER2 amplification was higher in the lymph nodes. The IMPC component with HER2 amplification is rarely seen and its positivity for CD10 is an unexpected finding for gastric IMPC. Hence, this is a highly unusual case judging by the literature; further studies are needed to clarify the nature of gastric IMPC.  相似文献   
86.
87.
Aims: Although body posture in relation to the dental condition has been of great interest in the dental profession, rumination bias has been a substantial obstacle to achieving a reliable objective evaluation of the intrinsic body posture. The aim of this study was to establish a posture control protocol that would minimize the effect of bias.

Methodology: Fifteen healthy male volunteers (23–33 years of age) participated in this study. The posture movement was recorded for 10 seconds by a three-dimensional motion capture system. The experiment was performed on four different days.

Results: The posture was most stable at 4–5 seconds after the start of the front bulb gaze (the mean coefficient of variation ranged from 0·1 to 44·1). The intraclass correlation coefficients for four days were 0·871–0·975 (P≤0·001).

Conclusions: It was concluded that the use of this measurement method helped in producing a reliable intrinsic standing posture where unbiased evaluation of the effect of any intervention on the body posture is researched.  相似文献   

88.
Neonatal estrogen treatment (NET) induces morphological changes in male reproductive organs. NET with β-estradiol 17-cypionate is reported to induce inflammation with stromal-epithelial abnormalities in the prostate and seminal vesicles in post-pubertal mice. The aim of this study was to investigate the histopathology of the testis, ductuli efferentes, epididymis, and vas deferens in mice after NET with β-estradiol 17-cypionate. No morphological changes in these organs were observed until 4 weeks after NET. However, some inflammatory cells were found in epididymis and vas deferens 6 weeks after NET. Eight weeks after NET, inflammatory cells spread to the ductuli efferentes and inflammation was severe from 6 to 12 weeks after NET. Inflammatory cells were never seen in the whole testis, but cystic dilatation of the rete testes with spermatogenic disturbance was found around the mediastinum testis. Many inflammatory cells emigrated into the lumen of the epididymis, resulting in complete absence of spermatozoa in the vas deferens. Most of the inflammatory cells penetrating into the epithelial layers of epididymal ducts were neutrophils. These results indicate that in post-pubertal mice, NET with β-estradiol 17-cypionate induces inflammation in the ductuli efferentes, epididymis, and vas deferens, but not in the testis, provoking obstructive azoospermia.  相似文献   
89.
Hepatitis B virus X (HBX) protein plays a crucial role in carcinogenesis, but its mechanism is unclear. The involvement of ataxia telangiectasia mutated (ATM) kinase in the enhanced redox system was investigated by examining the phosphorylation level of ATM in HBX gene-transfected cells and in transgenic mice following redox system manipulation by treatment with hydrogen peroxide (H2O2) or antioxidant. Western blotting and immunostaining showed that phospho-ATM was significantly increased by HBX both in vitro (3.2-fold; p<0.05) and in vivo (4-fold; p<0.05), and this effect was abrogated by antioxidant treatment. The level of PKC-δ in HBX-expressing cells was increased 3.5-fold compared to controls. Nuclear localized NF-E2-related factor 2 (Nrf2) was increased in HBX-expressing cells exposed to H2O2, but remained at lower levels after the treatment with rottlerin, KU55933, or caffeine. The levels of anti-oxidant molecules were increased in HBX expressing cells and in transgenic mice, indicating that HBX stimulates the Nrf2-mediated redox system. The levels of intracellular reactive oxygen species (ROS) were significantly increased in HBX-expressing cells treated with hydrogen peroxide in the presence of ATM inhibitor KU55933 or caffeine. Treatment of HBX-expressing cells with KU55933 or caffeine before the exposure to H2O2 increased the ratio of cell apoptosis to 33 ± 4% (p<0.05) and 22 ± 4% (p<0.05), respectively. Collectively, HBX stimulates the ATM-mediated PKC-δ/Nrf2 pathway, and maintains the enhanced activity of the redox system. Therefore, manipulating ATM kinase activity might be a useful strategy for treating HBX-induced carcinogenesis.  相似文献   
90.
Granulocyte colony-stimulating factor (G-CSF)-producing tumors are known for their aggressive behavior. Only four cases of G-CSF-producing colorectal carcinoma have been previously reported. Herein, we present a case of an undifferentiated carcinoma of the descending colon showing G-CSF production and giant cell carcinoma morphology in a 93-year-old woman. A tumor with a diameter of 80 mm was identified in the descending colon via computed tomography. Descending colectomy was performed involving the abdominal wall where tumor invasion was observed. The white blood cell count, which was elevated before resection, decreased to normal levels after intervention. However, local recurrence at the resected site was detected 39 days after surgery. Upon recurrence, increased white blood cell counts and serum G-CSF were seen. The patient died because of respiratory failure 98 days after colectomy. By using immunohistochemistry, G-CSF expression was detected in tumor cells in the resected specimen, along with overexpression of CD44 and highly proliferating nestin-positive tumor vessels. The poor clinical outcome of this patient is consistent with previous reports that the expression of these three molecules predict poor prognosis. While G-CSF can be a therapeutic target considering its auto/paracrine function to induce tumor growth via the G-CSF receptor, CD44 and nestin may also be possible candidate therapeutic targets. Further studies are required to assess the efficacy of treatments targeting these three molecules.  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