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   8272篇
  免费   666篇
  国内免费   11篇
耳鼻咽喉   170篇
儿科学   373篇
妇产科学   217篇
基础医学   936篇
口腔科学   227篇
临床医学   650篇
内科学   2135篇
皮肤病学   258篇
神经病学   565篇
特种医学   258篇
外科学   1458篇
综合类   26篇
一般理论   2篇
预防医学   711篇
眼科学   193篇
药学   385篇
中国医学   34篇
肿瘤学   351篇
  2023年   35篇
  2022年   78篇
  2021年   224篇
  2020年   124篇
  2019年   284篇
  2018年   276篇
  2017年   199篇
  2016年   209篇
  2015年   212篇
  2014年   299篇
  2013年   379篇
  2012年   431篇
  2011年   512篇
  2010年   347篇
  2009年   258篇
  2008年   396篇
  2007年   446篇
  2006年   457篇
  2005年   423篇
  2004年   384篇
  2003年   369篇
  2002年   357篇
  2001年   304篇
  2000年   356篇
  1999年   253篇
  1998年   66篇
  1997年   52篇
  1996年   55篇
  1995年   47篇
  1994年   38篇
  1993年   35篇
  1992年   133篇
  1991年   115篇
  1990年   102篇
  1989年   98篇
  1988年   55篇
  1987年   54篇
  1986年   47篇
  1985年   50篇
  1984年   34篇
  1983年   29篇
  1979年   27篇
  1975年   20篇
  1974年   18篇
  1973年   24篇
  1972年   22篇
  1971年   21篇
  1970年   18篇
  1969年   22篇
  1968年   19篇
排序方式: 共有8949条查询结果,搜索用时 15 毫秒
41.
BACKGROUND: A major consequence of malnutrition in cystic fibrosis (CF) patients is the loss of lean body mass (LBM) and the subsequent impairment of respiratory muscle function. AIM: To determine whether insulin-like growth factor I (IGF-I) could be related to the LBM depletion and the evolution of respiratory disease in CF patients. METHODS: LBM was evaluated by dual energy x ray absorptiometry; serum concentrations of IGF-I were measured in 24 CF patients twice with a one year interval. Both values were expressed as SD score (SDS) calculated from normal data for age, sex, and pubertal stage and analysed with respect to anthropometric evaluation and disease related conditions. RESULTS: At the initial evaluation, IGF-I SDS had a mean value of -0.98 (range -3.6 to 3.2) and correlated with weight for age index, LBM SDS, and lung disease related conditions. Multiple regression analysis showed that only LBM remained independently related to IGF-I, suggesting that the relation of IGF-I to LBM was independent of weight and that the correlation between IGF-I and the respiratory conditions was related to the level of LBM. IGF-I SDS at the first evaluation was lower for the patients who lost > or =5% of weight for age index or > or =1 SD of LBM between the two evaluations. CONCLUSION: Low levels of IGF-I could be crucial for clinical outcome by impairing LBM and respiratory function. IGF-I could be a tool for nutritional evaluation by identifying the CF patients at risk of LBM depletion.  相似文献   
42.
Contribution of a retrospective series of 16 patients with type II absorptive hypercalciuria over a total of 1.041 patients undergoing metabolic study due to relapsing renal lithiasis. Clinical history of lithiasis, biochemistry prior to treatment and instituted therapy were examined in all cases. Stones composition, radiologic appearance of lithiasis and evolution of biochemical parameters after medical treatment with a mixture of phosphates were also studied.  相似文献   
43.
We present 2-year-old patient with a allopecia lesions in scalp, and clinique diagnostic of Cutis Aplasia. The anatomopathologic study have diagnosed the lesions as Acquired Progressive Lymphangioma (APL). Is a rare vascular tumour that has a tendency to appear in childhood an to progress slowly over the years. It could present as a solitary erythematous macule or plaque and a simple excision is usually curative. Our patient is the youngest reported in the literature.  相似文献   
44.
PURPOSE: The purpose of this research was to identify promiscuous T-helper cell determinants (THd) from carcinoembryonic antigen (CEA) to be used to prime T-cell help for cancer therapy. CEA was selected because this antigen is expressed in an important variety of carcinomas. EXPERIMENTAL DESIGN: Potential promiscuous THd from CEA were predicted using available computer algorithms. Predicted peptides were synthesized and tested in binding experiments to different HLA-DR molecules. Binder peptides were then used to prime T-cell responses both in vitro and in vivo. RESULTS: Twenty 15-mer peptides from CEA were predicted to bind to different HLA-DR molecules. The promiscuous character of these peptides was demonstrated in binding experiments. Fifteen of 20 peptides tested were able to bind to HLA-DR4, but only CEA (625-639) was shown to be presented after processing of recombinant CEA. CEA (625-639) was also found to be presented by HLA-DR53. Moreover, immunization of HLA-DR4 transgenic mice with CEA (625-639) in conjunction with class I epitope OVA (257-264), induced a CTL response specific of OVA (257-264). CONCLUSIONS: CEA (625-639) might be a relevant promiscuous THd peptide for cancer therapy.  相似文献   
45.
PURPOSE: In recent years, the incidence of cutaneous melanoma has increased more than that of any other cancer. Dacarbazine is considered the gold standard for treatment, having a response rate of 15% to 20%, but most responses are not sustained. Previously, we have shown that short exposure of primary cutaneous melanoma cells to dacarbazine resulted in the upregulation of interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF). The purpose of the present study was to determine how long-term exposure of melanoma cells to dacarbazine would affect their tumorigenic and metastatic potential in vivo. MATERIALS AND METHODS: The primary cutaneous melanoma cell lines SB2 and MeWo were repeatedly exposed in vitro to increasing concentrations of dacarbazine, and dacarbazine-resistant cell lines SB2-D and MeWo-D were selected and examined for their ability to grow and metastasize in nude mice. RESULTS: The dacarbazine-resistant cell lines SB2-D and MeWo-D exhibited increased tumor growth and metastatic behavior in vivo. This increase could be explained by the activation of RAF, MEK, and ERK, which led to the upregulation of IL-8 and VEGF. More IL-8, VEGF, matrix metalloproteinase-2 (MMP-2), and microvessel density (CD-31) were found in tumors produced by SB2-D and MeWo-D in vivo than in those produced by their parental counterparts. No mutations were observed in BRAF. CONCLUSION: Our results have significant clinical implications. Treatment of melanoma patients with dacarbazine could select for a more aggressive melanoma phenotype. We propose that combination treatment with anti-VEGF/IL-8 or MEK inhibitors may potentiate the therapeutic effects of dacarbazine.  相似文献   
46.
47.
48.
Aprotinin is a protease inhibitor of interest for its antifibrinolytic effect of reducing perioperative bleeding in certain types of surgery, with wide use in heart surgery, liver transplantation and vascular surgery. The application of aprotinin during orthopedic surgery has recently been suggested. Such use is controversial, as there is lack of consensus as to the type of patient for whom aprotinin administration would be indicated, the surgical procedure during which it would be most effective (hip or knee arthroplasty, spinal arthrodesis, major tumor or septic surgery), the doses to administer, its safety and its real efficacy for conserving homologous blood. That is to say, there is no agreement as to the cost/benefit relation of aprotinin for the various types of orthopedic surgery. This critical review of the literature leads to the conclusion that aprotinin is a promising drug for use in orthopedic surgery, given that published studies have established the benefit in blood product savings and decreased blood loss during surgery.  相似文献   
49.

Objective

To study the epidemiology, clinical features, diagnosis, therapeutic management, and outcome of non-tuberculous mycobacterial lymphadenitis in a paediatric population of Aragón (Spain).

Material and methods

A retrospective study was conducted on patients under 15 years-old diagnosed with non-tuberculous mycobacterial lymphadenitis between the years 2000 and 2015. Inclusion criteria: patients with lymphadenitis and positive culture. Quantitative values are shown as mean, rank, and standard deviation, and qualitative data as frequencies.

Results

Twenty-seven cases were registered, with a mean age of presentation of 39.9 months (range 10 months–8 years). The mean time between the symptoms onset and first consultation was 1.7 ± 1.1 months. The most frequent location was sub-maxilar in 17/27 cases (63%), on the right side in 59.3%, and size 2.96 ± 1.26 cm. Fistulae were observed in 16/27 cases. Tuberculin test was greater than 10 mm in 7/24 (29.1%). Microbiological cultures were positive for Mycobacterium avium in 14/27 (51.9%), Mycobacterium intracellulare 3/27 (11.1%), and Mycobacterium lentiflavum 3/27 (11.1%). Combined treatment of antibiotics and surgery was given in 16/27 cases (59.8%), medical treatment only in7/27 (25.9%), and surgical exeresis alone in 4/27 (14.8%). Two patients required a new surgery, and one showed severe neutropenia secondary to rifabutin. Only one case (3.7%) suffered from temporary facial palsy as sequel.

Conclusions

The most frequent treatment was the combination of antibiotics and surgery. Delay in diagnosis seemed to be responsible for the limited number of exeresis as first option, only one for every seven patients.  相似文献   
50.
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