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   4393篇
  免费   164篇
  国内免费   12篇
耳鼻咽喉   30篇
儿科学   164篇
妇产科学   63篇
基础医学   512篇
口腔科学   140篇
临床医学   557篇
内科学   678篇
皮肤病学   23篇
神经病学   485篇
特种医学   110篇
外科学   563篇
综合类   26篇
一般理论   1篇
预防医学   405篇
眼科学   15篇
药学   342篇
肿瘤学   455篇
  2021年   28篇
  2020年   34篇
  2019年   42篇
  2018年   57篇
  2017年   41篇
  2016年   49篇
  2015年   52篇
  2014年   89篇
  2013年   162篇
  2012年   229篇
  2011年   210篇
  2010年   146篇
  2009年   124篇
  2008年   281篇
  2007年   293篇
  2006年   277篇
  2005年   316篇
  2004年   265篇
  2003年   277篇
  2002年   255篇
  2001年   62篇
  2000年   31篇
  1999年   48篇
  1998年   70篇
  1997年   77篇
  1996年   66篇
  1995年   52篇
  1994年   47篇
  1993年   39篇
  1992年   39篇
  1991年   40篇
  1990年   27篇
  1989年   30篇
  1988年   34篇
  1987年   31篇
  1986年   36篇
  1985年   39篇
  1984年   40篇
  1983年   46篇
  1982年   50篇
  1981年   42篇
  1980年   36篇
  1979年   29篇
  1978年   30篇
  1977年   32篇
  1976年   22篇
  1975年   29篇
  1974年   21篇
  1968年   23篇
  1967年   24篇
排序方式: 共有4569条查询结果,搜索用时 15 毫秒
81.
A systematic assessment of radiotherapy for cancer was conducted by The Swedish Council on Technology Assessment in Health Care (SBU) and published in 1996. The assessment reviewed the scientific literature up to 1993 on the use of radiotherapy in the treatment of solid tumours, and estimated the costs associated with radiotherapy. It also described the current practise of radiotherapy in Sweden 1992 and compared practise with scientific knowledge. The SBU has now conducted a follow-up study on radiotherapy for cancer, including a review of the scientific literature from 1994 and a prospective survey of radiotherapy practise in Sweden 2001. The following conclusions were drawn: The role of radiotherapy as an important form of treatment for cancer with both curative and palliative intent has been further confirmed.The use of radiotherapy in Sweden has increased and is now at the internationally recommended level.Radiotherapy in Sweden is mostly given in accordance with the scientific evidence but may still be underutilized in certain situations.The resources for radiotherapy are being utilized more efficiently.The costs of radiotherapy are still 5% of the total cost of cancer care, while the cost of an individual treatment (fraction) has decreased.The need for radiotherapy capacity will increase. In addition, half of the treatment equipment will have to be replaced in the next few years.  相似文献   
82.
[18F] FDG PET in Gastric Non-Hodgkin's Lymphoma   总被引:1,自引:0,他引:1  
The possibility of using [18F] FDG PET for assessment of tumor extension in primary gastric non-Hodgkin's lymphoma (NHL) was studied in 8 patients (6 high-grade and 2 Iow-grade, one of the MALT type) and in a control group of 7 patients (5 patients with NHL without clinical signs of gastric involvement, 1 patient with NHL and benign gastric ulcer and 1 patient with adenocarcinoma of the stomach). All patients with gastric NHL and the two with benign gastric ulcer and adenocarcinoma, respectively, underwent endoscopy including multiple biopsies for histopathological diagnosis. All patients with high-grade and one of the two with low-grade NHL and the patient with adenocarcinoma displayed high gastric uptake of [18F] FDG corresponding to the pathological findings at endoscopy and/or CT. No pathological tracer uptake was seen in the patient with low-grade gastric NHL of the MALT type. In 6/8 patients with gastric NHL, [18F] FDG PET demonstrated larger tumor extension in the stomach than was found at endoscopy, and there was high tracer uptake in the stomach in two patients who were evaluated as normal on CT. [18F] FDG PET correctly excluded gastric NHL in the patient with a benign gastric ulcer and in the patients with NHL without clinical signs of gastric involvement. Although the experience is as yet limited, [18F] FDG PET affords a novel possibility for evaluation of gastric NHL and would seem valuable as a complement to endoscopy and CT in selected patients, where the technique can yield additional information decisive for the choice of therapy.  相似文献   
83.
During the past two decades many different treatment regimens of combination chemotherapy have been applied in extensive stage small-cell lung cancer (SCLC). This study was carried out to identify whether these modifications have resulted in an improved overall survival for extensive stage during the past two decades. In total, 1111 patients with extensive stage SCLC were included in six consecutive randomised trials in our setting from 1973 until 1992. Of these, 526 patients treated in the early period (1973–1981) were compared with 585 patients treated in the late period (1981–1992) with respect to pretreatment prognostic factors, staging, treatment and outcome. No change in the distribution of prognostic factors was detected and the frequency of patients with extensive stage was equal in the two periods, and no difference in overall response rates and survival was observed (P=0.49). Median survival in the two periods was 208 days and 215 days, respectively. No stage migration or treatment-related improved outcome was observed in extensive disease. We suggest restricting aggressive treatment to patients with favorable prognosis and long-term survival as a realistic aim.  相似文献   
84.
85.
BACKGROUND: Epidemiologic evidence of an association between tobacco smoking and non-Hodgkin's lymphoma has been conflicting. This may reflect that non-Hodgkin's lymphoma comprises several distinct disease entities with different etiologies, as some studies have indicated an association between smoking and follicular lymphoma. OBJECTIVE: To investigate the association between cigarette smoking and non-Hodgkin's lymphoma risk, overall and by subtype. METHODS: As part of a nationwide Danish-Swedish population-based case-control study, we interviewed 3,055 incident non-Hodgkin's lymphoma patients and 3,187 population controls. All lymphomas were uniformly classified according to the WHO classification. We used unconditional logistic regression to estimate adjusted odds ratios (OR) and 95% confidence intervals (95% CI) for the association between cigarette smoking and risk of non-Hodgkin's lymphoma. RESULTS: Cigarette smoking was not associated with the risk of non-Hodgkin's lymphoma overall (OR, 0.97; 95% CI, 0.87-1.08) nor with the major subgroups such as diffuse large B-cell lymphoma (OR, 0.94; 95% CI, 0.79-1.10), chronic lymphocytic leukemia (OR, 0.86; 95% CI, 0.72-1.02), or follicular lymphoma (OR, 1.03; 95% CI, 0.85-1.24). Female smokers were at a marginally increased risk of follicular lymphoma (OR, 1.41; 95% CI, 1.04-1.92). Men who had ever smoked had a significantly increased risk of T-cell lymphoma (OR, 1.67; 95% CI, 1.11-2.51). No dose-response association with cigarette smoking could be established for any lymphoma subgroup. CONCLUSION: We found little evidence of an association between cigarette smoking and non-Hodgkin's lymphoma risk overall. Although increased risks of follicular lymphoma in female smokers and of T-cell lymphoma in male smokers were suggested, no dose-response relationship was observed, leaving limited support for causality.  相似文献   
86.
87.
88.
Fatty acid composition of serum lipids and adipose tissue triacylglycerols (AT-TAG) partly reflect dietary fatty acid intake. The fatty acid composition is, besides the diet, also influenced by desaturating enzymes that can be estimated using product-to-precursor fatty acid ratios. The interrelationships between desaturase indices derived from different serum lipid fractions and adipose tissue are unclear, as well as their associations with obesity and insulin resistance. We aimed to investigate cross-sectional correlations between desaturase indices as measured in serum lipid fractions (phospholipids; PL and free fatty acids; FFA) and in adipose tissue (AT-TAG). In a population-based sample of 301 healthy 60-year-old men various desaturase indices were assessed: stearoyl-CoA-desaturase (16:1n-7/16:0; SCD-16 and 18:1n-9/18:0; SCD-18, respectively), delta-6-desaturase (20:3n-6/18:2n-6; D6D) and delta-5-desaturase (20:4n-6/20:3n-6; D5D). Correlations with BMI and insulin resistance (HOMA-IR) were also examined. SCD-16 and D5D were significantly correlated between fractions and tissues (all r > 0.30), whereas SCD-18 and D6D were not. Desaturase indices in serum FFA and AT-TAG were significantly correlated; SCD-16 (r = 0.63), SCD-18 (r = 0.37), and D5D (r = 0.43). In phospholipids, SCD-16 was positively correlated to BMI (r = 0.15), while D5D negatively to both BMI (r = -0.30) and HOMA-IR (r = -0.31), all p < 0.01. D6D in both phospholipids and AT-TAG was positively correlated to HOMA-IR and BMI (all p < 0.01). In conclusion, SCD-1 and D5D activity indices showed overall strong correlations between lipid pools. SCD-1 activity index in adipose tissue is best reflected by 16:1/16:0-ratio in serum FFA, but associations with obesity and insulin resistance differ between these pools. D5D in PL was inversely related to obesity and insulin resistance, whereas D6D index showed positive associations.  相似文献   
89.
OBJECTIVE: To evaluate the influence of the laparoscopic technique in hernia repair regarding time to full recovery and return to work, complications, recurrence rate, and economic aspects. SUMMARY BACKGROUND DATA: Several studies have shown advantages in terms of less pain and faster recovery after laparoscopic hernia repair, whereas others have not, and the cost-effectiveness has been questioned. The laparoscopic technique must be thoroughly compared with the open procedures before its true place in hernia surgery can be defined. METHODS: Six hundred thirteen male patients aged 40 to 75 years were randomized to the conventional procedure, preperitoneal mesh placed by the open technique, or laparoscopic preperitoneal mesh (TAPP). Follow-up was after 7 days, 8 weeks, and 1 year. RESULTS: Of 613 patients undergoing surgery, 604 (98.5%) were followed for 1 year. Patients who underwent TAPP gained full recovery after 18.4 days, compared with 24.2 days for open mesh (p < 0.001) and 26.4 days for the conventional procedure (p < 0.001). Patients who underwent TAPP returned to work after 14.7 days, compared with 17.7 days for open mesh (p = 0.05) and 17.9 days for the conventional procedure (p = 0.04). They also had significantly less restriction in physical activities after 7 days. The TAPP procedure was more expensive, mainly as a result of longer surgical time and equipment costs, even after compensation for earlier return to work. Complications were more common in the TAPP group, with a varying pattern between the groups. Four recurrences in the conventional, 11 in the open mesh, and 4 in the TAPP group were recorded after 1 year (p = n.s.). CONCLUSION: The laparoscopic technique results in both shorter time to full recovery and shorter time to return to work, at the price of substantially increased costs.  相似文献   
90.
脊髓刺激(spinal cord stimulation,SCS)是通过植入电极从而在不同的脊髓节段进行的电刺激方法,Shealy在1967年首次使用脊髓刺激治疗疼痛病人.  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