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   6208篇
  免费   327篇
  国内免费   27篇
耳鼻咽喉   101篇
儿科学   166篇
妇产科学   197篇
基础医学   599篇
口腔科学   191篇
临床医学   426篇
内科学   1319篇
皮肤病学   101篇
神经病学   297篇
特种医学   153篇
外科学   1374篇
综合类   157篇
一般理论   3篇
预防医学   476篇
眼科学   127篇
药学   475篇
中国医学   33篇
肿瘤学   367篇
  2023年   67篇
  2022年   191篇
  2021年   268篇
  2020年   165篇
  2019年   210篇
  2018年   257篇
  2017年   164篇
  2016年   193篇
  2015年   209篇
  2014年   221篇
  2013年   323篇
  2012年   513篇
  2011年   544篇
  2010年   280篇
  2009年   237篇
  2008年   327篇
  2007年   342篇
  2006年   314篇
  2005年   300篇
  2004年   266篇
  2003年   246篇
  2002年   222篇
  2001年   53篇
  2000年   40篇
  1999年   51篇
  1998年   41篇
  1997年   30篇
  1996年   21篇
  1995年   23篇
  1994年   14篇
  1993年   22篇
  1992年   17篇
  1991年   20篇
  1990年   16篇
  1989年   26篇
  1988年   22篇
  1987年   21篇
  1986年   21篇
  1985年   18篇
  1984年   24篇
  1983年   23篇
  1982年   23篇
  1981年   25篇
  1980年   24篇
  1979年   10篇
  1978年   10篇
  1977年   16篇
  1976年   15篇
  1975年   12篇
  1974年   10篇
排序方式: 共有6562条查询结果,搜索用时 0 毫秒
101.
Clinical Rheumatology - Adult-onset Still’s disease (AOSD) characterized by a high spiking fever, skin rash, arthritis, and leukocytosis. The aim of the present study was considering the...  相似文献   
102.
Growth differentiation factor 15 (GDF15) plays an important role in cancer pathophysiology and prognosis. However, limited studies analyzed its level and prognostic value in acute myeloid leukemia (AML) patients. This study included 56 adult AML patients. Serum GDF15 level was measured at diagnosis in all patients by enzyme-linked immunosorbent assay. Remission and survival statuses were assessed at 90 days following treatment. GDF15 level was significantly higher in patients than in controls (P < 0.001). GDF15 level correlated positively with age (P < 0.001), hemoglobin level (P = 0.027), and platelet count (P = 0.024). High GDF15 above the median level was associated with inferior OS (P = 0.044) together with high platelet count (P = 0.006) and high bone marrow blast percent (P = 0.038). There was no statistically significant difference between patients with GDF15 above and below the median level regarding DFS (P = 0.881). On multivariate analysis for OS, GDF15 level was an independent risk factor (P = 0.047). In conclusion, serum GDF15 level is significantly elevated in AML patients and high GDF15 level is associated with inferior OS.  相似文献   
103.
The coronavirus disease 2019 (COVID-19) pandemic is a threat worldwide for individuals of all ages, including children. Gastrointestinal manifestations could be the initial presenting manifestation in many patients, especially in children. These symptoms are more common in patients with severe disease than in patients with non-severe disease. Approximately 48.1% of patients had a stool sample that was positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral RNA. Children typically form 1%-8% of all laboratory-confirmed cases of SARS-CoV-2. Gastrointestinal manifestations of COVID-19 in children are not rare, with a prevalence between 0 and 88%, and a wide variety of presentations, including diarrhoea, vomiting, and abdominal pain, can develop before, with or after the development of respiratory symptoms. Atypical manifestations such as appendicitis or liver injury could also appear, especially in the presence of multisystem inflammatory disease. In this review, we discussed the epidemiology of COVID-19 gastrointestinal diseases in children as well as their implications on the diagnosis, misdiagnosis, prognosis, and faecal-oral transmission route of COVID-19 and the impact of gastrointestinal diseases on the gut microbiome, child nutrition, and disease management.  相似文献   
104.
DNA extracted from 31 primary colorectal carcinomas was analyzed for the presence ofras gene amplification and mutations. Nine carcinomas had Ha-ras amplification and seven Ki-ras amplification. Nine carcinomas had codon 12 Ki-ras mutations. Immunohistochemical staining forras proteins revealed a normal membrane association in normal mucosa and benign polyps but an abnormal cytoplasmic distribution in carcinomas. Amplification, mutations, and immunohistochemical staining were independent of histologic differentiation, Duke's stage, or DNA ploidy status. This study demonstrates that abnormalities ofras genes are a common finding in colorectal carcinomas. They are potentially important biologic changes associated with malignancy, although they do not appear to be related to clinical behavior. Supported by The Cancer Research Campaign and the North West Regional Health Authority.  相似文献   
105.
Exhaled nitric oxide is age-dependent in asthma   总被引:1,自引:0,他引:1  
We determined whether the exhaled nitric oxide (eNO) level in asthmatics is age-dependent. Eighty-seven asthmatic patients aged 2-41 years were studied. Hyperreactivity to adenosine 5'-monophosphate (AMP) was used to confirm asthma (相似文献   
106.
The impact of bone marrow fibrosis grade on the prognosis of patients with chronic myelomonocytic leukemia (CMML) remains controversial. Therefore, we examined the records of 82 patients diagnosed with CMML at our institution and summarized baseline characteristics and molecular profiles by subgroups of absent or mild (grades 0/1) and moderate (grade 2) fibrosis. Cox proportional hazards models were constructed to assess the prognostic significance of fibrosis grade. Grade 2 fibrosis was identified in 63 patients (76.8%), grade 1 in 16 patients (19.5%), and grade 0 in 3 patients (3.7%). Grade 2 fibrosis was associated with reduced hemoglobin levels (median 9.75 vs 11.0 g/dL in grade 0/1; p?=?0.04) and increased percentages of ringed sideroblasts (7.5 vs 0%; p?=?0.008). In multivariable analysis, grade 2 fibrosis was an independent predictor of poor overall survival (OS; 95% CI 1.32–6.35; HR 2.90; p?=?0.008), but not event-free survival (EFS; 95% CI 0.62–2.67; HR 1.28; p?=?0.50). Absolute neutrophil count (ANC) was found to impact OS (95% CI 1.01–1.09; HR 1.05; p?=?0.009), while both ANC (95% CI 1.00–1.07; HR 1.04; p?=?0.04) and peripheral blood blast percentage (95% CI 1.02–1.32; HR 1.16; p?=?0.02) impacted EFS. These results implicate fibrosis grade is an important indicator of prognosis, with high-grade fibrosis predicting inferior survival. Given the prevalence of marrow fibrosis in CMML, fibrosis grading should be incorporated into prognostic assessment and therapeutic decision-making.  相似文献   
107.
OBJECTIVES--Cytokines, released from mononuclear cells (MNC) are mediators of joint destruction in rheumatoid arthritis (RA). The mechanisms of action of gold salts used in the treatment of RA are unknown. The aim of this study was to investigate cytokine expression and intensity of MNC infiltrate in the RA synovial membrane (SM) following treatment with sodium aurothiomalate (SAT). METHODS--Sequential blind needle biopsies were obtained at entry into the study and at two and 12 weeks after the start of SAT therapy in 10 patients with active RA. SMs were stained with a panel of monoclonal antibodies to assess cytokine expression (IL-1 alpha, IL-1 beta, TNF-alpha, IL-6, and GM-CSF). RESULTS--There was a significant decrease in IL-1 alpha, IL-1 beta, IL-6 and TNF-alpha expression 12 weeks after treatment (p < 0.004, p < 0.002, p < 0.009 and p < 0.004 respectively). This was noted in the lining layer, the perivascular aggregates and the connective tissue areas. Detailed examination of the MNC infiltrate showed a significant reduction in inflammatory monocytes (MONO) in the lining layer at two weeks (p < 0.03). A decrease in the number of CD68+ macrophages (MAC) was noted in the perivascular and connective tissue areas at 12 weeks. No significant changes were observed in the number of T and B cells and blood vessels. CONCLUSION--The results suggest that gold may suppress RA disease activity by diminishing MONO and MAC numbers and consequently monokine production in the SM.  相似文献   
108.
Individuals harboring the loss-of-function (LOF) proprotein convertase subtilisin/kexin type 9 Gln152His variation (PCSK9Q152H) have low circulating low-density lipoprotein cholesterol levels and are therefore protected against cardiovascular disease (CVD). This uncleavable form of proPCSK9, however, is retained in the endoplasmic reticulum (ER) of liver hepatocytes, where it would be expected to contribute to ER storage disease (ERSD), a heritable condition known to cause systemic ER stress and liver injury. Here, we examined liver function in members of several French-Canadian families known to carry the PCSK9Q152H variation. We report that PCSK9Q152H carriers exhibited marked hypocholesterolemia and normal liver function despite their lifelong state of ER PCSK9 retention. Mechanistically, hepatic overexpression of PCSK9Q152H using adeno-associated viruses in male mice greatly increased the stability of key ER stress-response chaperones in liver hepatocytes and unexpectedly protected against ER stress and liver injury rather than inducing them. Our findings show that ER retention of PCSK9 not only reduced CVD risk in patients but may also protect against ERSD and other ER stress–driven conditions of the liver. In summary, we have uncovered a cochaperone function for PCSK9Q152H that explains its hepatoprotective effects and generated a translational mouse model for further mechanistic insights into this clinically relevant LOF PCSK9 variant.  相似文献   
109.
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