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   8937篇
  免费   479篇
  国内免费   29篇
耳鼻咽喉   195篇
儿科学   86篇
妇产科学   42篇
基础医学   1285篇
口腔科学   227篇
临床医学   506篇
内科学   2247篇
皮肤病学   174篇
神经病学   591篇
特种医学   238篇
外科学   1949篇
综合类   36篇
一般理论   1篇
预防医学   246篇
眼科学   112篇
药学   597篇
中国医学   14篇
肿瘤学   899篇
  2023年   53篇
  2022年   105篇
  2021年   191篇
  2020年   74篇
  2019年   100篇
  2018年   133篇
  2017年   116篇
  2016年   149篇
  2015年   140篇
  2014年   181篇
  2013年   216篇
  2012年   375篇
  2011年   394篇
  2010年   210篇
  2009年   212篇
  2008年   373篇
  2007年   425篇
  2006年   396篇
  2005年   410篇
  2004年   424篇
  2003年   410篇
  2002年   413篇
  2001年   335篇
  2000年   305篇
  1999年   329篇
  1998年   131篇
  1997年   108篇
  1996年   98篇
  1995年   81篇
  1994年   94篇
  1993年   72篇
  1992年   184篇
  1991年   148篇
  1990年   158篇
  1989年   188篇
  1988年   185篇
  1987年   174篇
  1986年   163篇
  1985年   166篇
  1984年   93篇
  1983年   83篇
  1980年   51篇
  1979年   102篇
  1978年   63篇
  1977年   51篇
  1975年   54篇
  1974年   49篇
  1972年   54篇
  1971年   46篇
  1969年   48篇
排序方式: 共有9445条查询结果,搜索用时 15 毫秒
101.
Systemic venous return to the heart is disturbed as a result of right heart failure. ICG clearance is known to be influenced by hepatic venous return to the right atrium. Under a hypothesis that right heart function could be evaluated by ICG clearance test, patients with mitral valve disease (Group M, n = 29), aortic valve disease (Group A, n = 16), ischemic heart disease (Group CABG, n = 19) were studied. Preoperative K-ICG (normal range > 0.17) in the Group M was significantly lower than those in the Group A and Group CABG (0.097 +/- 0.037 vs 0.166 +/- 0.032 and 0.171 +/- 0.027, p < 0.05). In the Group M, patients who underwent tricuspid annuloplasty (TAP) had significantly lower K-ICG than the others (0.077 +/- 0.026 vs 0.113 +/- 0.038, p < 0.05). Postoperatively, K-ICG of TAP patients significantly increased (0.092 +/- 0.031, p < 0.05) when compared to their preoperative value. ICG clearance test was useful to quantify the right heart function, especially in the postoperative evaluation.  相似文献   
102.
To tune and test the generalizability of a deep learning-based model for assessment of COVID-19 lung disease severity on chest radiographs (CXRs) from different patient populations.A published convolutional Siamese neural network-based model previously trained on hospitalized patients with COVID-19 was tuned using 250 outpatient CXRs. This model produces a quantitative measure of COVID-19 lung disease severity (pulmonary x-ray severity (PXS) score). The model was evaluated on CXRs from 4 test sets, including 3 from the United States (patients hospitalized at an academic medical center (N = 154), patients hospitalized at a community hospital (N = 113), and outpatients (N = 108)) and 1 from Brazil (patients at an academic medical center emergency department (N = 303)). Radiologists from both countries independently assigned reference standard CXR severity scores, which were correlated with the PXS scores as a measure of model performance (Pearson R). The Uniform Manifold Approximation and Projection (UMAP) technique was used to visualize the neural network results.Tuning the deep learning model with outpatient data showed high model performance in 2 United States hospitalized patient datasets (R = 0.88 and R = 0.90, compared to baseline R = 0.86). Model performance was similar, though slightly lower, when tested on the United States outpatient and Brazil emergency department datasets (R = 0.86 and R = 0.85, respectively). UMAP showed that the model learned disease severity information that generalized across test sets.A deep learning model that extracts a COVID-19 severity score on CXRs showed generalizable performance across multiple populations from 2 continents, including outpatients and hospitalized patients.  相似文献   
103.
Neurokinin 2 receptor (NK2R), a G protein‐coupled receptor for neurokinin A (NKA), a tachykinin family member, regulates various physiological functions including pain response, relaxation of smooth muscle, dilation of blood vessels, and vascular permeability. However, the precise role and regulation of NK2R expression in cancer cells have not been fully elucidated. In this study, we found that high NK2R gene expression was correlated with the poor survival of colorectal cancer patients, and Interferon (IFN‐α/β) stimulation significantly enhanced NK2R gene expression level of colon cancer cells in a Janus kinas 1/2 (JAK 1/2)‐dependent manner. NKA stimulation augmented viability/proliferation and phosphorylation of Extracellular‐signal‐regulated kinase 1/2 (ERK1/2) levels of IFN‐α/β‐treated colon cancer cells and NK2R blockade by using a selective antagonist reduced the proliferation in vitro. Administration of an NK2R antagonist alone or combined with polyinosinic‐polycytidylic acid, a synthetic analog of double‐stranded RNA, to CT26‐bearing mice significantly suppressed tumorigenesis. NK2R‐overexpressing CT26 cells showed enhanced tumorigenesis and metastatic colonization in both lung and liver after the inoculation into mice. These findings indicate that IFN‐α/β‐mediated NK2R expression is related to the malignancy of colon cancer cells, suggesting that NK2R blockade may be a promising strategy for colon cancers.  相似文献   
104.
An 82-year-old female was referred to our hospital because a 16 x 8 cm tumor detected in her liver by abdominal ultrasonography (echo, hereafter) and CT. The patient was diagnosed as having highly advanced cholangiocellular carcinoma (CCC) by abdominal angiography. Since excision of the tumor was impossible due to the patient's age, a reservoir was indwelled for intra-arterial injection into the liver. Continuous injection of 1,000 mg 5-FU over 24 hours was performed every 2 weeks using a portable disposable pump 70 times. The tumor has been markedly reduced since the start of chemotherapy, with a reduction rate (PR) of 98% over the 3 years until the present. Since the frequency of administration was low, only twice a month, the patient had few side effects despite her old age, and injections could be performed in the outpatient department. Usually, the prognosis for CCC is poor. However, the patient has maintained a good QOL with the periodic intra-arterial injection of the carcinostatic into the liver, and this treatment has had a strong antitumor effect. This chemotherapy is thus considered useful for CCC which can not be resected.  相似文献   
105.
106.
107.
Interstitial pneumonia (IP) is a major risk factor for lung adenocarcinoma (LADC). IP-related LADC predominantly develops in the bronchiolar metaplasia lining in honeycomb lesions. Kirsten rat sarcoma virus (KRAS) is the most common oncogene mutated in IP-related LADC. The present study examined the metaplastic epithelia in honeycomb lesions for KRAS mutations using digital droplet polymerase chain reaction (ddPCR), a sensitive method used to detect infrequent mutations. Significantly higher KRAS mutation variant allele frequencies (VAFs) were detected in the metaplastic lung epithelia from 13 patients with IP compared with those in 46 non-lesioned lung samples from patients without IP (G12V, P=0.0004, G12C, P=0.0181, and G12A, P=0.0234; Mann Whitney U test). Multivariate analyses revealed that higher KRAS G12V (logistic regression model; P=0.0133, odds ratio=7.11) and G12C (P=0.0191, odds ratio=5.81) VAFs in patients with IP were independent of confounding variables, such as smoking and age. In patients with IP, metaplastic epithelia exhibited significantly higher KRAS G12V and G12C VAFs compared with the non-lesioned counterparts (paired t-test; G12V, P=0.0158, G12C, P=0.0465). These results suggested that IP could increase KRAS mutations and supported the hypothesis that bronchiolar metaplasia could be a precursor for IP-related LADC.  相似文献   
108.
Chylous ascites (CA) is the accumulation of fluid with a high triglyceride content in the peritoneal cavity. Only two cases in the literature have reported CA with hyperthyroidism. A 28-year-old previously healthy woman presented with gradual-onset abdominal swelling, exertional dyspnea, and diarrhea. Hyperthyroidism and heart failure were diagnosed using laboratory investigation and echocardiography. Ultrasonography revealed a large amount of ascites. The ascitic fluid was milky with elevated triglyceride levels. Treatment with anti-thyroid therapy and diuretics improved all symptoms, and the free triiodothyronine (T3) level normalized after five days. Hyperthyroidism and heart failure should be considered as reversible causes of CA.  相似文献   
109.
Objective The quality of life and activities of daily living (ADL) are generally poor among dialysis patients after intracerebral hemorrhaging, and their precise clinical course remains unclear. In addition, the association between the severity of cerebral hemorrhaging and the long-term prognosis in these patients has not been fully elucidated. This study aimed to evaluate the subsequent prognosis of hemodialysis patients who survived the acute phase of intracerebral hemorrhaging. Methods We included hemodialysis patients who were admitted to Nagasaki University Hospital between 2007 and 2015 for intracerebral hemorrhaging treatment. After excluding cases of in-hospital death, survivors were classified using the 5-point modified Rankin Scale (mRS), which specifically measures the ADL in patients with cerebrovascular diseases. The patients were followed up at the medical facilities to which they were transferred in the same medical zone until 2017. Results Out of 91 patients with cerebral hemorrhaging (65±11 years old, 66% men, hemodialysis duration 108±91 months), 62 survived until discharge. Twenty-one patients died during observation, largely due to infectious diseases, such as sepsis and pneumonia (n=16, 76%). Compared to patients with mRS 0-4 (n=31), those with mRS 5 (n=31) showed a significantly poorer prognosis. The hazard ratio adjusted for age and antiplatelets was 13.7 (95% confidence interval: 3.88-63.7, p<0.001). Conclusion Hemodialysis patients with intracerebral hemorrhaging who were bedridden showed poor outcomes. The major causes of death were infections. Therefore, these patients should be carefully monitored for infections in order to improve their prognosis.  相似文献   
110.
A 64-year-old Japanese man who worked at a butcher shop was hospitalized for a fever, headache, and deafness. We diagnosed him with sepsis and meningitis caused by Streptococcus suis infection. The patient''s renal function declined rapidly, and hemodialysis was performed temporarily. A renal biopsy was performed, and the renal function tended to improve with antimicrobial therapy. This case seemed rather similar to one of staphylococcal-associated nephritis in that it showed mesangial proliferative nephritis with immunoglobulin A deposition, even though the nephritis was caused by streptococci. Similarly, intramembranous electron-dense deposits were characteristic findings. We present new findings of an in vivo renal biopsy in a case of S. suis-associated glomerulonephritis.  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