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   1715篇
  免费   113篇
  国内免费   2篇
耳鼻咽喉   33篇
儿科学   169篇
妇产科学   42篇
基础医学   237篇
口腔科学   31篇
临床医学   145篇
内科学   284篇
皮肤病学   30篇
神经病学   56篇
特种医学   28篇
外科学   194篇
综合类   25篇
预防医学   130篇
眼科学   137篇
药学   112篇
中国医学   7篇
肿瘤学   170篇
  2023年   14篇
  2022年   36篇
  2021年   53篇
  2020年   36篇
  2019年   45篇
  2018年   56篇
  2017年   47篇
  2016年   45篇
  2015年   39篇
  2014年   65篇
  2013年   84篇
  2012年   150篇
  2011年   161篇
  2010年   95篇
  2009年   59篇
  2008年   112篇
  2007年   119篇
  2006年   90篇
  2005年   129篇
  2004年   96篇
  2003年   83篇
  2002年   85篇
  2001年   7篇
  2000年   12篇
  1999年   10篇
  1998年   14篇
  1997年   12篇
  1996年   5篇
  1995年   8篇
  1994年   3篇
  1993年   8篇
  1991年   6篇
  1990年   4篇
  1989年   7篇
  1988年   3篇
  1987年   5篇
  1986年   3篇
  1984年   3篇
  1983年   3篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1977年   2篇
  1975年   1篇
  1974年   2篇
  1973年   3篇
  1972年   2篇
  1963年   1篇
  1961年   1篇
排序方式: 共有1830条查询结果,搜索用时 15 毫秒
101.
"Drip breast milk" is that milk which spontaneously drips from the contralateral breask during the suckling of an infant. Biochemically and immunologically, pooled drip milk resembled pooled mature expressed breast milk, although it has a lower fat concentration. About 15% of lactating women are capable of producing drip milk; volumes produced are up to 188 ml/donor/day. A milk bank is described which processes 1400 liters of drip milk/yr. Heat treatment of this milk with a semi-automated holder pasteurizer caused a 21% reduction in IgA concentration and a 36% reduction in lysozyme activity, as well as a decrease in the ability of the milk to inhibit the growth of E. coli. In comparison with boiling, pasteurization was as effective in reducing total bacterial content provided the milk initially contained fewer than 10(6) bacteria/ml.  相似文献   
102.
103.
The development of resistance to variety of chemotherapeutic agents is one of the major challenges in effective cancer treatment. Tumor cells are able to generate a multi-drug resistance (MDR) phenotype due to microenvironmental selection pressures. This review addresses the use of nanotechnology-based delivery systems to overcome MDR in solid tumors. Our own work along with evidence from the literature illustrates the development of various types of engineered nanocarriers specifically designed to enhance tumor-targeted delivery through passive and active targeting strategies. Additionally, multi-functional nanocarriers are developed to enhance drug delivery and overcome MDR by either simultaneous or sequential delivery of resistance modulators (e.g., with P-glycoprotein substrates), agents that regulate intracellular pH, agents that lower the apoptotic threshold (e.g., with ceramide), or in combination with energy delivery (e.g., sound, heat, and light) to enhance the effectiveness of anticancer agents in refractory tumors. In preclinical studies, the use of multi-functional nanocarriers has shown significant promise in enhancing cancer therapy, especially against MDR tumors.  相似文献   
104.

Background:

Tumour gene expression analysis is useful in predicting adjuvant chemotherapy benefit in early breast cancer patients. This study aims to examine the implications of routine Oncotype DX testing in the UK.

Methods:

Women with oestrogen receptor positive (ER+), pNO or pN1mi breast cancer were assessed for adjuvant chemotherapy and subsequently offered Oncotype DX testing, with changes in chemotherapy decisions recorded. A subset of patients completed questionnaires about their uncertainties regarding chemotherapy decisions pre- and post-testing. All patients were asked to complete a diary of medical interactions over the next 6 months, from which economic data were extracted to model the cost-effectiveness of testing.

Results:

Oncotype DX testing resulted in changes in chemotherapy decisions in 38 of 142 (26.8%) women, with 26 of 57 (45.6%) spared chemotherapy and 12 of 85 (14.1%) requiring chemotherapy when not initially recommended (9.9% reduction overall). Decision conflict analysis showed that Oncotype DX testing increased patients'' confidence in treatment decision making. Economic analysis showed that routine Oncotype DX testing costs £6232 per quality-adjusted life year gained.

Conclusion:

Oncotype DX decreased chemotherapy use and increased confidence in treatment decision making in patients with ER+ early-stage breast cancer. Based on these findings, Oncotype DX is cost-effective in the UK setting.  相似文献   
105.
Type 2 diabetic subjects failing glyburide therapy were randomized to receive additional therapy with either metformin (2,550 mg/day) or troglitazone (600 mg/day) for 3-4 months. Biopsies of subcutaneous abdominal adipose tissue were obtained before and after therapy. Glycemic control was similar with both treatments. Metformin treatment increased insulin-stimulated whole-body glucose disposal rates by 20% (P < 0.05); the response to troglitazone was greater (44% increase, P < 0.01 vs. baseline, P < 0.05 vs. metformin). Troglitazone-treated subjects displayed a tendency toward weight gain (5 +/- 2 kg, P < 0.05), increased adipocyte size, and increased serum leptin levels. Metformin-treated subjects were weight-stable, with unchanged leptin levels and reduced adipocyte size (to 84 +/- 4% of control, P < 0.005). Glucose transport in isolated adipocytes from metformin-treated subjects was unaltered from pretreatment. Glucose transport in both the absence (321 +/- 134% of pre-Rx, P < 0.05) and presence of insulin (418 +/- 161%, P < 0.05) was elevated after troglitazone treatment. Metformin treatment had no effect on adipocyte content of GLUT1 or GLUT4 proteins. After troglitazone treatment, GLUT4 protein expression was increased twofold (202 +/- 42%, P < 0.05). Insulin-stimulated serine phosphorylation of Akt was augmented after troglitazone (170 +/- 34% of pre-Rx response, P < 0.05) treatment and unchanged by metformin. We conclude that the ability of troglitazone to upregulate adipocyte glucose transport, GLUT4 expression, and insulin signaling can contribute to its greater effect on whole-body glucose disposal.  相似文献   
106.
The comparative decomposition of chickpea residue, and chopped and unchopped wheat straw was investigated in pits for 120 days. Microbial biomass, humus, C/N ratio, pH, Electrical conductivity (EC), dehydrogenase, alkaline phosphatase, cellulase, xylanase, total phenol and soluble protein were determined to assess their response to the addition of inorganic nitrogen and mixed fungal inoculum of Aspergillus nidulans, Phanerochaete chrysosporium and Trichoderma viride. The evaluation of physico-chemical parameters (organic matter, organic carbon, N, C/N, pH, EC, microbial biomass) revealed that by supplementing unchopped wheat straw with 1% urea and mixed fungal inoculum, a lowest C/N ratio of 10.7, lowest biomass of 9.54 and highest humus content of 13% can be achieved within 3 months. Germination of Lepidium sativum (cress seeds) showed a germination index >60%, in this treatment. The enzyme assay for dehydrogenase indicated highest microbial activity in uninoculated treatments compared to fungal inoculated counterparts, in the second month sampling (active phase of composting). However, cellulase and xylanase activity showed an upward trend during curing phase of composting. Chickpea residue compost, though resulted in a C/N ratio of 17.3, but its germination index was less than 60%. The rapid quality tests conducted for H2S, NH3, NO3 and starch confirmed the stability and maturity of finished compost prepared from wheat straw through microbial inoculants.  相似文献   
107.
108.
The present study investigates cardioprotective effect of Sida rhomboidea. Roxb (SR) extract on heart weight, plasma lipid profile, plasma marker enzymes, lipid peroxidation, endogenous enzymatic and non-enzymatic antioxidants and membrane bound ATPases against isoproterenol (IP) induced myocardial necrosis (MN) in rats. Rats treated with IP (85 mg/kg, s.c.) recorded significant (p<0.05) increment in heart weight, plasma lipid profile, plasma marker enzymes of cardiac damage, cardiac lipid peroxidation (LPO) and activity levels of Ca+2 ATPase whereas there was significant (p<0.05) decrease in plasma HDL, cardiac endogenous enzymatic and non-enzymatic antioxidants, Na+-K+ ATPase and Mg+2 ATPase. Pre-treatment with SR extract (400 mg/kg per day, p.o.) for 30 consecutive days followed by IP injections on days 29th and 30th, showed significant (p<0.05) decrease in heart weight, plasma lipid profile, plasma marker enzymes of cardiac damage, cardiac lipid peroxidation, Ca+2 ATPase and significant increase in plasma HDL, cardiac endogenous enzymatic and non-enzymatic antioxidants, Na+-K+ ATPase and Mg+2 ATPase compared to IP treated group. Hence, this study is the first scientific report on cardioprotective effect of SR against IP induced MN in rats.  相似文献   
109.

Objective  

The present study was conducted to assess the utility of serum transferrin receptor (sTfR) and sTfR ferritin indices to differentiate ACD from IDA and also to diagnose coexisting IDA and ACD.  相似文献   
110.
We present a large single-center series (>2200 cases) operated for Tetralogy of Fallot (TOF). We analyzed the incidence of associated unusual and uncommonly described cardiac lesions and their diagnostic and therapeutic implications in TOF patients. This retrospective study was conducted by reviewing records of patients operated for TOF at a large tertiary care pediatric cardiac centre. From 2002 to 2008, a total of 2235 cases of TOF were evaluated with echocardiography, cardiac catheterization, and/or cardiac computed tomography followed by cardiac surgery. Known and well-described associations were excluded from the study. Unusual associations were tabulated. Several unusual associations having an incidence >0.1% were detected. These included subaortic membrane (1%), pulmonary venous abnormalities (0.5%), small left ventricle (0.5%), interrupted inferior vena cava (0.5%), mitral valve abnormalities (0.4%), hemitruncus (0.4%), tricuspid valve abnormalities (0.4%), biventricular dysfunction (0.3%), retroaortic innominate vein (0.3%), bicuspid aortic valve (0.2%), and pericardial effusion (0.2%). This series describes unusual, not previously routinely reported cardiac lesions associated with TOF that may affect management and should be sought on preoperative evaluation. We demonstrate that more unusual associations do exist in not infrequent numbers, i.e., a TET is not just a TET.  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