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   2998篇
  免费   152篇
  国内免费   22篇
耳鼻咽喉   94篇
儿科学   51篇
妇产科学   14篇
基础医学   426篇
口腔科学   46篇
临床医学   176篇
内科学   785篇
皮肤病学   70篇
神经病学   173篇
特种医学   115篇
外科学   538篇
综合类   8篇
预防医学   53篇
眼科学   35篇
药学   142篇
中国医学   8篇
肿瘤学   438篇
  2023年   19篇
  2022年   35篇
  2021年   77篇
  2020年   21篇
  2019年   49篇
  2018年   58篇
  2017年   66篇
  2016年   66篇
  2015年   75篇
  2014年   97篇
  2013年   96篇
  2012年   167篇
  2011年   162篇
  2010年   91篇
  2009年   95篇
  2008年   184篇
  2007年   196篇
  2006年   166篇
  2005年   204篇
  2004年   205篇
  2003年   199篇
  2002年   203篇
  2001年   39篇
  2000年   41篇
  1999年   52篇
  1998年   40篇
  1997年   41篇
  1996年   37篇
  1995年   34篇
  1994年   21篇
  1993年   22篇
  1992年   36篇
  1991年   20篇
  1990年   20篇
  1989年   17篇
  1988年   12篇
  1987年   10篇
  1986年   20篇
  1985年   17篇
  1984年   17篇
  1983年   24篇
  1982年   12篇
  1981年   12篇
  1980年   13篇
  1979年   9篇
  1978年   7篇
  1973年   6篇
  1969年   9篇
  1968年   7篇
  1965年   5篇
排序方式: 共有3172条查询结果,搜索用时 15 毫秒
51.
PURPOSE: To determine the prevalence of use of complementary and alternative medicine (CAM) by patients with cancer in Japan, and to compare the characteristics of CAM users and CAM nonusers. PATIENTS AND METHODS: A questionnaire on cancer CAM and the Hospital Anxiety and Depression Scale were delivered to 6,607 patients who were treated in 16 cancer centers and 40 palliative care units. RESULTS: There were 3,461 available replies for a response rate of 52.4%. The prevalence of CAM use was 44.6% (1,382 of 3,100) in cancer patients and 25.5% (92 of 361) in noncancer patients with benign tumors. Multiple logistic regression analysis determined that history of chemotherapy, institute (palliative care units), higher education, an altered outlook on life after cancer diagnosis, primary cancer site, and younger age were strongly associated with CAM use in cancer patients. Most of the CAM users with cancer (96.2%) used products such as mushrooms, herbs, and shark cartilage. The motivation for most CAM use was recommendation from family members or friends (77.7%) rather than personal choice (23.3%). Positive effects were experienced by 24.3% of CAM users with cancer, although all of them received conventional cancer therapy concurrently. Adverse reactions were reported by 5.3% of cancer patients. CAM products were used without sufficient information by 57.3% of users with cancer and without a consultation with a doctor by 60.7% of users. CONCLUSION: This survey revealed a high prevalence of CAM use among cancer patients, without sufficient information or consultation with their physicians. Oncologists should not ignore the CAM products used by their patients because of a lack of proven efficacy and safety.  相似文献   
52.
L-leucine, an essential amino acid, is one of the most popular ingredients in dietary supplements. To investigate a possibility of its embryo-fetal toxicity in rats, 11- to 12-week old dams were orally administered an aqueous solution of L-leucine at doses of 300 or 1000 mg/kg body weight on gestational days 7-17. Body weight and feed intake was evaluated throughout the whole course of pregnancy (days 0-20). L-Leucine did not influence body weight, but at a dose of 1000 mg/kg, slightly enhanced feed intake on days 14 and 18 of pregnancy. Caesarean section (day 20) revealed no influences on the litter size and weight of live-born fetuses, the number of corpora lutea, implantation index or the quality of placenta, and the minor increase in feed intake was considered irrelevant to the pregnancy outcomes. Fetuses were evaluated in a battery of external, visceral and skeletal examinations. No effects of L-leucine on gender ratio and external abnormalities, and no significant treatment-related variations in visceral and skeletal pathologies were observed. These results suggested that L-leucine, administered orally during organogenesis at doses up to 1000 mg/kg body weight, did not affect the outcome of pregnancy and did not cause fetotoxicity in rats.  相似文献   
53.
54.
BackgroundThe purpose of this study was to investigate residual acetabular retroversion after skeletal maturity in patients with Pemberton osteotomy.Patients and methodsWe compared 40 hips in 36 patients treated with a Pemberton osteotomy (Pemberton group) and 30 hips in 26 patients treated only with a Pavlik harness (Rb group) for developmental dysplasia of the hip. The average age at operation in the Pemberton group was 94.5 months and the follow-up duration was 151.8 months. Radiographic parameters included the acetabular index (a angle) and the center-edge angle of Wiberg, preoperatively and at skeletal maturity. We examined the crossover sign (COS) at the latest follow-up as a sign of acetabular retroversion (AR). We compared the parameters between the two groups and examined the risk factors for acetabular retroversion using a multivariate Cox model.ResultA COS (+) was significantly more frequent in the Pemberton group compared to the Rb group [15 hips (37.5 %) vs 3 hips (10 %); p = 0.0077]. In the Pemberton group, the average age at operation in COS (+) hips was significantly older than that in COS (—) hips (126.9 vs 72.8 months; p = 0.0005). The preoperative α angle did not vary between hips with and without COS; however, the postoperative α angle was significantly smaller in COS (+) hips. A multiple logistic regression analysis for prediction of COS (+) showed that the age at operation and the amount change of α angle were significant predictors for COS (+) hips. The cut-off of the age at operation was 7 years and 9 months old.ConclusionsAR was present in 37.5 % of the hips in the Pemberton group after skeletal maturity. Remodeling of acetabular version was observed in younger patients; however, hips in older patients (> 8 years) at the time of operation and greater degrees of correction tended to result in AR.  相似文献   
55.
PurposeTo compare left adrenal venous sampling (AVS) in two locations: the central adrenal vein and the common trunk.Materials and MethodsA total of 22 patients (12 men and 10 women; mean age, 50 y; range, 26–65 y) who were suspected of having primary aldosteronism (PA) and underwent successful AVS with cortisol concentration measurement and/or venography between November 2010 and August 2011 were retrospectively analyzed. In regard to the left adrenal vein, collections were done at two locations: at the common trunk below the confluence of the inferior phrenic vein and at the central adrenal vein, which was above the confluence. The effects of the inflow from the inferior phrenic vein on plasma aldosterone and cortisol levels were analyzed.ResultsEight patients had bilateral hypersecreting lesions and 13 had a unilateral lesion. One was diagnosed as having secondary hypertension other than PA. The median cortisol levels below and above the confluence were 129 μg/dL (range, 21–400 μg/dL) and 215 μg/dL (range, 21–690 μg/dL), respectively. The median aldosterone levels were 2,120 pg/mL (range, 164–42,700 pg/mL) and 4,275 pg/mL (range, 119–59,000 pg/mL), respectively. The median aldosterone/cortisol (A/C) ratios were 244 (range, 34–2,401) and 278 (range, 25–2,251), respectively. Cortisol and aldosterone levels were significantly higher above the confluence (P = .0050 and P = .0003, respectively), whereas the A/C ratio showed no significant difference (P = .12).ConclusionsAlthough higher levels of cortisol and aldosterone were obtained upstream, A/C ratio was not significantly different between the central adrenal vein and the common trunk.  相似文献   
56.
57.
Abstract

This study aimed to characterize the effect of different running modes on serum irisin concentrations in rats. A total of 18, 10-week-old rats were divided into three groups; control group, 16° uphill running group (concentric exercise; CON) and, ?16° downhill running group (eccentric exercise; ECC). The running group’s rats ran on the inclined treadmill at 16?m/min, for a total of 90?min. Blood was drawn from the rats, 48?h after running, after which the rats were anesthetized. The serum concentrations of irisin were measured using enzyme-linked immunosorbent assays. Vastus intermedius was collected for immunohistochemical analysis. After multiple comparisons, the ECC showed a significantly high serum irisin concentration (ECC: 28.42?±?6.31?ng/ml, CON: 21.27?±?3.03?ng/ml) and a larger irisin antibody reactive cross-sectional area in vastus intermedius compared to the CON (p?<?0.05). This is the first study to reveal that single bout downhill running increases serum irisin concentrations in rats.  相似文献   
58.
59.
60.
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