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   1358篇
  免费   75篇
  国内免费   19篇
耳鼻咽喉   43篇
儿科学   59篇
妇产科学   88篇
基础医学   136篇
口腔科学   25篇
临床医学   118篇
内科学   230篇
皮肤病学   20篇
神经病学   116篇
特种医学   103篇
外科学   193篇
综合类   28篇
预防医学   38篇
眼科学   83篇
药学   39篇
中国医学   1篇
肿瘤学   132篇
  2022年   8篇
  2021年   22篇
  2020年   15篇
  2019年   13篇
  2018年   33篇
  2017年   12篇
  2016年   20篇
  2015年   27篇
  2014年   34篇
  2013年   73篇
  2012年   58篇
  2011年   56篇
  2010年   64篇
  2009年   60篇
  2008年   57篇
  2007年   45篇
  2006年   29篇
  2005年   45篇
  2004年   36篇
  2003年   37篇
  2002年   34篇
  2001年   32篇
  2000年   43篇
  1999年   32篇
  1998年   41篇
  1997年   33篇
  1996年   27篇
  1995年   22篇
  1994年   20篇
  1993年   16篇
  1992年   27篇
  1991年   22篇
  1990年   37篇
  1989年   35篇
  1988年   28篇
  1987年   17篇
  1986年   18篇
  1985年   19篇
  1984年   14篇
  1983年   13篇
  1982年   10篇
  1981年   9篇
  1980年   13篇
  1979年   15篇
  1978年   13篇
  1977年   10篇
  1976年   10篇
  1975年   9篇
  1973年   9篇
  1972年   12篇
排序方式: 共有1452条查询结果,搜索用时 15 毫秒
101.
BACKGROUND: Efforts to mimic the biologic olfactory system have resulted in the development of an electronic nose, whereby volatile gases may be identified by means of organic semiconductors. Such devices have been used in the food and beverage industry for quality-control purposes, but to date have not been used in the field of medicine. OBJECTIVE: To present the application of an electronic nose for clinical decision making by assessing the ability of an electronic nose to distinguish cerebrospinal fluid (CSF) from serum. DESIGN: Randomized, prospective, masked study. SUBJECTS: Nineteen matched sets of CSF and serum from inpatients at a university hospital. RESULTS: The electronic nose was able to distinguish CSF from serum in 18 of 19 patients. The data points for 18 of 19 CSF and 18 of 19 serum samples were within statistically distinct cluster groups, suggesting that the device is able to identify an unknown sample as CSF or serum. CONCLUSIONS: This new technology is able to distinguish CSF from serum with a high degree of accuracy and speed, and with small sample quantity, potentially allowing the physician to identify reliably CSF otorrhea or rhinorrhea. This revolutionary diagnostic approach may have further, widespread application in the field of otorhinolaryngology and in medicine as a whole.  相似文献   
102.
The present analysis was performed to evaluate the impact of cytosine arabinoside (ara-C) dose escalation on hematological and cytogenetic responses in patients with chronic myelogenous leukemia (CML) who failed to respond to low-dose ara-C (LD ara-C) at a dose of 10 mg/m2/d over 10 days per month and interferon-alpha (IFNalpha, 3.5 MU/d). Following the same administration schedule, dose escalation of ara-C to 15 and 20 mg/m2/d 1-10 was performed in 36 of 119 patients (30%) due to inadequate hematological response and/or disease progression. As a result, improvement of hematological and cytogenetic responses was achieved in 22 (61%) and nine (25%) patients, respectively. Escalated ara-C dose levels were usually well tolerated, although some patients experienced deterioration of preexisting side effects. Our results support the critical role of ara-C dose towards a better disease control in CML.  相似文献   
103.
Purpose: Experiments were undertaken to determine if metabolic changes induced by Motexafin gadolinium (Gd-Tex+2, XCYTRIN) predict time intervals between drug and radiation wherein there is enhancement of radiation efficacy.

Methods and Materials: We evaluated the effect of Gd-Tex+2 on tumor metabolism and on tumor growth using a mouse mammary carcinoma model and 31P nuclear magnetic resonance (NMR) experiments. Response to therapy was evaluated based on time for the tumor to regrow to pretreatment size and also tumor doubling time.

Results: 31P NMR experiments indicated that Gd-Tex+2 effected tumor energy metabolism during the first 24 hours postadministration. A decrease in phosphocreatine was noted at 2 (p < 0.04), 6 (p < 0.006), and 24 (p < 0.001) hours post Gd-Tex+2. A decrease in nucleoside triphosphates was noted only at 2 hours (p < 0.02), with subsequent recovery at 6 hours. Phosphocreatine in control (saline treated) tumors showed a significant decrease only at 24 hours (p < 0.01). Irradiation at 2 and 6 hours post Gd-Tex+2 induced an enhanced effect compared to radiation alone as measured by analyzing the growth curves, maximum tumor volumes, and the time for the tumors to regrow to their initial volumes. Irradiation at 24 hours post Gd-Tex+2 induced a modest enhancement in tumor growth delay compared to radiation alone.

Discussion: NMR spectroscopy may be useful for monitoring tumor metabolism after treatment with Gd-Tex+2 and administering radiation during the time of maximal efficacy of Gd-Tex+2.  相似文献   

104.
OBJECTIVE: To determine whether children's food consumption is increased by the size of the group of children in which they are eating. DESIGN: Crossover study. SETTING: University based preschool. PARTICIPANTS: 54 children, aged 2.5-6.5 years. INTERVENTIONS: Each child ate a standardised snack in a group of three children, and in a group of nine children. MAIN OUTCOME MEASURES: Amount each individual child consumed, in grams. RESULTS: Amount eaten and snack duration were correlated (r = 0.71). The association between group size and amount eaten differed in the short (<11.4 min) versus the long (> or =11.4 min) snacks (p = 0.02 for the interaction between group size and snack duration). During short snacks, there was no effect of group size on amount eaten (16.7 (SD 11) g eaten in small groups vs 15.1 (6.6) g eaten in large groups, p = 0.42). During long snacks, large group size increased the amount eaten (34.5 (16) vs 26.5 (13.8), p = 0.02). The group size effect was partially explained by a shorter latency to begin eating, a faster eating rate and reduced social interaction in larger groups. CONCLUSIONS: Children consumed 30% more food when eating in a group of nine children than when eating in a group of three children during longer snacks. Social facilitation of food consumption operates in preschool-aged children. The group size effect merits consideration in creating eating behaviour interventions.  相似文献   
105.
Purpose: Within this phase II EORTC trial, we have investigated the safety and efficacy of pentostatin in lymphoid malignancies. We have previously reported the results in T- and B-cell prolymphocytic leukemia, B-cell chronic lymphocytic leukemia (B-CLL) and hairy cell leukemia. This report focuses on the outcome in T-cell malignancies: T-CLL, Sézary syndrome (Sézary), mycosis fungoides (MF) and T-zone lymphoma (TZL).Patients and methods: Of the 92 patients with these diagnoses enrolled, 76 were evaluable for response and toxicity, i.e., 25 of 28 with T-CLL, 21 of 26 with Sézary, 22 of 26 with MF, and 8 of 12 with TZL. All patients had progressive and advanced disease. Pentostatin was administered at a dosage of 4 mg/m2 every week for the first 3 weeks, then 4 mg/m2 every 14 days for another 6 weeks, followed by maintenance therapy of 4 mg/m2 monthly for a maximum of 6 months.Results: Response rates (complete and partial responses) in patients with Sézary (n = 22) or MF (n = 21) were 33% and 23%, respectively, and in patients with T-CLL (n = 21) or TZL (n = 8) 8% and 25%, respectively. Sixteen (21%) patients died during the first ten weeks of treatment: twelve of progressive disease, two of infectious complications with progressive disease, one of myocard infarction and one of renal failure related to administration of i.v. contrast. Major toxicity (grade 3–4) included infection in 11% of patients, nausea/vomiting in 4%, diarrhea in 3%. Hematologic toxicity was mild to non-existent.Conclusions: We conclude that pentostatin is active in Sézary and MF but showed marginal activity in T-CLL or TZL. Toxicities are mild to moderate at the dose schedule administered. Due to its relatively specific lympholytic effect and its favorable toxicity spectrum, pentostatin might be especially useful for the palliative treatment of T-cell malignancies.  相似文献   
106.
应用局部皮瓣修复虎口狭窄   总被引:1,自引:0,他引:1  
马显杰  鲁开化  艾玉峰 《医学争鸣》1999,20(11):945-945
0 引言 外伤或烧伤后,所致的虎口瘢痕挛缩、狭窄,临床上较常见,修复方法亦较多[1~3].我科自1991-01~1997-06应用局部皮瓣修复虎口狭窄17例,方法简便,效果较好.1 临床资料 本组17例,24个虎口.男性11例,女性6例.年龄3岁~4...  相似文献   
107.
PURPOSE: To evaluate the relationship between contrast acuity at declining contrast levels and the type and density of lens opacity in cataract. METHODS: Contrast acuity at declining contrast levels was determined with the Holladay Contrast Acuity Test, in relation to the type and density of age-related cataract in 180 patients with bilateral cataract and 20 control subjects with normal macular function. Cataracts were graded according to the Lens Opacities Classification System (LOCS) III of nuclear color (NC), nuclear opalescence (NO), cortical (C), and posterior subcapsular (P) cataract. Best-corrected visual acuity and near contrast acuity were determined in randomized order monocularly in both eyes. Visual difficulties in everyday life were evaluated, using the VF-14 questionnaire and the Cataract Symptom Score. RESULTS: The contrast-dependent effect of cataract on contrast acuity was statistically significant (P < 0.001; two-way ANOVA). In the comparison of early, intermediate, and advanced nuclear, nuclear-cortical, and posterior subcapsular cataracts (PSCs), significantly reduced contrast acuity scores were found for the PSC groups (P < 0.001). Comparison of nuclear and nuclear-cortical cataracts showed the contrast acuity scores to be comparable at all contrast levels (P > 0.05). High correlation coefficients were found between the LOCS III P score and the contrast acuity measurements (r = 0.77-0.84; P < 0.001). In contrast, the correlation coefficients of the NO, NC, and C scores were considerably lower (r = 0.45-0.66; P < 0.001). High correlation coefficients were also found between the contrast acuity measurements and self-reported functional vision. CONCLUSIONS: The statistically significant, contrast-dependent effect of cataract on contrast acuity supports the clinical relevance of recording visual acuity at low contrast levels in patients with age-related cataract. Particularly, the severity of PSC has a strong influence on the impairment of contrast acuity. Contrast acuity corresponded closely to the self-reported visual difficulties in everyday life.  相似文献   
108.
109.
Founder effect in spinal and bulbar muscular atrophy (SBMA)   总被引:3,自引:2,他引:3  
We analyzed the polymorphic (CAG)n and (GGC)n repeats of the androgen receptor gene in 113 unrelated X-linked spinal and bulbar muscular atrophy (SBMA) X chromosomes and 173 control X chromosomes in Japanese males. The control chromosomes had an average CAG repeat number of 21 +/- 3 with a range from 14-32 repeat units, and SBMA chromosomes had a range from 40-55 with a median of 47 +/- 3 copies. The control chromosomes had seven different alleles of the (GGC)n repeat with the range of 11 to 17; the most frequent size of (GGC)n was 16 (79%), while (GGC)17 was very rare (1%). However, in SBMA chromosomes only two alleles were seen; the most frequent size of (GGC)n was 16 (61%) followed by 17 (39%). (GGC)n size distribution was significantly different between SBMA and control chromosomes (P < 0.0001), indicating the presence of linkage disequilibrium. There was no allelic association between the (CAG)n and (GGC)n microsatellites among control subjects as well as SBMA patients, which suggests that a founder effect makes a more significant contribution to generation of Japanese SBMA chromosomes than new mutations.   相似文献   
110.
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