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   2854篇
  免费   141篇
  国内免费   9篇
耳鼻咽喉   90篇
儿科学   44篇
妇产科学   30篇
基础医学   314篇
口腔科学   64篇
临床医学   174篇
内科学   741篇
皮肤病学   58篇
神经病学   137篇
特种医学   317篇
外科学   236篇
综合类   18篇
预防医学   160篇
眼科学   73篇
药学   154篇
中国医学   5篇
肿瘤学   389篇
  2023年   30篇
  2022年   74篇
  2021年   107篇
  2020年   42篇
  2019年   84篇
  2018年   84篇
  2017年   67篇
  2016年   62篇
  2015年   49篇
  2014年   97篇
  2013年   93篇
  2012年   164篇
  2011年   190篇
  2010年   102篇
  2009年   89篇
  2008年   147篇
  2007年   163篇
  2006年   131篇
  2005年   123篇
  2004年   129篇
  2003年   125篇
  2002年   111篇
  2001年   73篇
  2000年   80篇
  1999年   57篇
  1998年   27篇
  1997年   22篇
  1996年   19篇
  1995年   12篇
  1994年   16篇
  1993年   9篇
  1992年   49篇
  1991年   51篇
  1990年   40篇
  1989年   37篇
  1988年   34篇
  1987年   36篇
  1986年   46篇
  1985年   34篇
  1984年   14篇
  1983年   13篇
  1981年   4篇
  1979年   12篇
  1978年   7篇
  1977年   4篇
  1975年   4篇
  1974年   8篇
  1973年   7篇
  1971年   4篇
  1968年   6篇
排序方式: 共有3004条查询结果,搜索用时 0 毫秒
71.
72.
An 80-year-old man visited our hospital because of dyspnea on exertion from 6 months ago. Echo Doppler study showed severe calcification in the aortic valve with restricted movement and the sigmoid septum causing obstruction at the LV outflow tract (LVOT). Considering the aortic valve area (AVA) might have been inaccurately estimated, we carried out beta-blocker stress echocardiography. The transaortic pressure gradient and AVA were respectively calculated as 52 mmHg and 0.90 cm2 before propranolol administration and as 64 mmHg and 0.86 cm2 after propranolol administration. Thus, beta-blocker stress echocardiography may provide an accurate assessment of AS if the LVOT obstruction is concomitant.  相似文献   
73.
74.
Sodium-glucose cotransporter-2 inhibitors (SGLT2) are drugs that have been reported to have several effects through the regulation of plasma volume, for example, antihypertensive effects. This study aimed to clarify the impact of long-term administration and subsequent discontinuation of the SGLT2 inhibitor tofogliflozin on estimated plasma volume (ePV), brain natriuretic peptide (BNP) and the relationship between changes in ePV, BNP and body weight (BW). Data from 157 participants with type 2 diabetes receiving tofogliflozin monotherapy in a phase 3 study were analysed. Changes in variables or correlations among them during a 52-week administration and a 2-week post-treatment period were investigated. Percent change in ePV was calculated using the Strauss formula. Significant decreases in BW, ePV and ln-transformed BNP (ln-BNP) were noted by week 52. %ΔBW was not significantly correlated with %ΔePV and Δln-BNP, while %ΔePV was significantly correlated with Δln-BNP. Two weeks after discontinuation of tofogliflozin, BW, ePV and ln-BNP were significantly increased. %ΔBW was significantly correlated with %ΔePV and Δln-BNP. Furthermore, ePV and BNP were significantly higher than baseline levels.  相似文献   
75.
Pseudomonas aeruginosa, responsible for serious nosocomial-acquired infections, possesses intrinsic antibiotic resistance mechanisms and commonly exhibits multidrug resistance. Here, we report the evolving resistance profiles of strains isolated from the sputum of a patient being treated for repeated P. aeruginosa infections following cancer resection. Whole genome sequencing of six isolates obtained over a 2-month period revealed two key single nucleotide polymorphisms in the mexR and gyrB genes that affected efflux pump expression and antimicrobial resistance.  相似文献   
76.
Asymptomatic colorectal cancer detected by screening   总被引:2,自引:1,他引:2  
PURPOSE: Colorectal cancer screening has become prevalent. To discuss the efficacy of screening, we studied the characteristics of asymptomatic Colorectal cancer detected by screening. METHODS: This is a retrospective review of patients with colorectal cancer treated at our institution. During the past 20 years, 96 of 1,046 cases of colorectal cancer were asymptomatic and detected by screening. Sixty-one of these cases were detected in the recent five years. The initial screening procedures were fecal occult blood test in 51 cases, sigmoidoscopy or colonoscopy in 18, barium enema in 9, and other tests in 18. RESULTS: Thirteen lesions (14 percent) were smaller than 1.0 cm and 32 (33 percent) were 1–2 cm in size. There were 34 Tis, 21 T1, and 8 T2 tumors. Of the 55 Tis or T1 lesions, 14 showed nonpolypoid growth (5 flat-elevated, 7 flat-elevated with depression, 1 flat, 1 depressed), and 12 of these were detected on endoscopy. Thirty-four cases were TNM Stage 0, 25 were Stage I, 16 were Stage II, 12 were Stage III, and 9 were Stage IV. Sixty-one percent of those detected by screening were in either Stage 0 or Stage I compared with 16 percent in the symptomatic group. Cumulative five-year disease-free survival rates were 100 percent for both Stage 0 and Stage I, 94 percent for Stage II, and 52 percent for Stage III. Overall cumulative five-year survival rate was 87 percent for those detected by screening, compared with 57 percent in symptomatic patients. CONCLUSIONS: Asymptomatic cancers detected by screening were at a less advanced stage. In particular, many nonpolypoid early cancers were detected by endoscopic screening.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Montreal, Quebec, Canada, May 7 to 12, 1995.  相似文献   
77.
Totsune K  Takahashi K  Arihara Z  Sone M  Satoh F  Ito S  Kimura Y  Sasano H  Murakami O 《Lancet》2001,358(9284):810-811
Urotensin II is a potent vasoconstrictor, which also has some vasodilatory properties. We investigated its expression in various tissues and in the plasma of patients with renal dysfunction. Plasma concentrations of urotensin II-like immunoreactivity were 2-fold higher in patients not on dialysis and 3-fold higher in those on haemodialysis thanin healthy individuals. Messenger RNA encoding theurotensin II precursor and the urotensin II receptor precursor were expressed in various human tissues. The peptidemight act as an important regulator in the cardiovascularand renal systems. Urotensin II antagonists could, therefore, be useful in the treatment of diseases affecting theseorgans.  相似文献   
78.
Restenosis after coronary artery stent implantation is attributed chiefly to intimal hyperplasia, which is prevented experimentally by angiotensin-converting enzyme (ACE) inhibitors. Therefore, the present study investigated whether the effect of quinapril, a tissue-specific ACE inhibitor, on the prevention of coronary restenosis differs according to ACE polymorphism. One hundred consecutive patients with successful stent implantation were randomly assigned to quinapril and control groups. Both follow-up angiography and ACE polymorphism analysis were obtained from 92 patients (control, 46; quinapril treatment, 46). The prevalence of risk factors did not differ statistically according to quinapril treatment or ACE genotypes. There was no statistically significant difference in the occurrence of restenosis 6 months after stenting between the groups. Quantitative coronary angiography revealed that quinapril treatment resulted in significantly higher minimal lumen diameter and significantly lower percent diameter stenosis (22.9 +/- 22.6 vs 37.1 +/- 19.7% in the control group, p < 0.05) in patients with the D allele although there was no difference in those with the II genotype. In addition, intravascular ultrasound revealed that quinapril treatment significantly prevented the loss of minimal lumen cross-sectional area and the increase in percent area stenosis (34.5 +/- 14.0 vs 53.3 +/- 16.4% in the control group, p < 0.05) in patients with the D allele compared to those with the II genotype. These results suggest that the administration of ACE inhibitors for the attenuation of lumen loss after coronary stent implantation is best for subjects with the D allele of the ACE genotype.  相似文献   
79.
80.
We evaluated a new rapid urinary antigen detection kit. NOW Streptococcus pneumoniae (Binax Inc., USA) that detected S. pneumoniae antigen by immunochromatographic membrane assay, with 66 Japanese adult patients of community acquired pneumonia. Twenty-two (33.3%) patients were found to be positive with the kit and S. pneumoniae was isolated from six patients (27.3%) of these 22 patients. S. pneumoniae was not isolated from eight of the 22 patients by blood or sputum culture. Analysis of clinical laboratory data showed that the levels of C-reactive protein (CRP) in the serum were significantly higher in the urine-antigen positive group than those in the urine-antigen negative group. There were no significant difference between the two groups including renal function, urinalysis, clinical symptom, and severity of pneumonia. Our study suggests that more cases of community acquired pneumonia are caused by S. pneumoniae than conventional tests can currently confirm. Since it is not technically complex, does not require equipment, and detects within as quickly as in 15 minutes, the S. pneumoniae urinary antigen kit is useful for rapid diagnosis of community acquired pneumonia in adults.  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