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   2191篇
  免费   143篇
  国内免费   2篇
耳鼻咽喉   60篇
儿科学   79篇
妇产科学   46篇
基础医学   284篇
口腔科学   37篇
临床医学   172篇
内科学   565篇
皮肤病学   52篇
神经病学   129篇
特种医学   168篇
外科学   225篇
综合类   21篇
预防医学   169篇
眼科学   70篇
药学   104篇
中国医学   7篇
肿瘤学   148篇
  2023年   6篇
  2022年   15篇
  2021年   52篇
  2020年   21篇
  2019年   56篇
  2018年   56篇
  2017年   46篇
  2016年   41篇
  2015年   46篇
  2014年   63篇
  2013年   108篇
  2012年   107篇
  2011年   108篇
  2010年   81篇
  2009年   84篇
  2008年   93篇
  2007年   102篇
  2006年   99篇
  2005年   102篇
  2004年   97篇
  2003年   100篇
  2002年   75篇
  2001年   82篇
  2000年   93篇
  1999年   74篇
  1998年   42篇
  1997年   41篇
  1996年   41篇
  1995年   29篇
  1994年   34篇
  1993年   26篇
  1992年   25篇
  1991年   24篇
  1990年   13篇
  1989年   30篇
  1988年   30篇
  1987年   26篇
  1986年   27篇
  1985年   20篇
  1984年   11篇
  1983年   10篇
  1982年   8篇
  1981年   10篇
  1980年   5篇
  1979年   9篇
  1978年   9篇
  1977年   17篇
  1976年   9篇
  1975年   10篇
  1968年   4篇
排序方式: 共有2336条查询结果,搜索用时 187 毫秒
91.
Reliable, quick and low-cost methods are needed for the early detection of multidrug-resistant and highly virulent high-risk B2 and D Escherichia coli clones or clonal complexes (HiRCC). Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) seems to have a good discriminatory potential at different subspecies levels, but it was never evaluated for the discrimination of E. coli clones. We assessed the potential of MALDI-TOF MS coupled to multivariate data analysis to discriminate representative E. coli B2 and D HiRCC. Seventy-three E. coli isolates from B2 (including ST131 and B2 non-ST131 clones) and D (ST69, ST393, ST405) with variable pulsed-field gel electrophoresis (PFGE) patterns, origins and dates (1980–2010) were tested. MS spectra were acquired from independent extracts obtained from different plate cultures in two different Microflex LT MALDI-TOF devices (Bruker) after a standard extraction procedure. MALDI-TOF MS fingerprinting analysis revealed a good discriminatory ability between the four HiRCC analysed (ST131, ST69, ST405, ST393) and between B2 ST131 and other B2 non-ST131 isolates. Clusters defined by MALDI-TOF MS were consistent with the clonal complexes assigned by multilocus sequence typing (MLST), although differences were detected regarding the composition of clusters obtained by the comparison of PFGE profiles. We demonstrate, for the first time, that characteristic mass fingerprints of different E. coli HiRCC are sufficiently discriminatory and robust to enable their differentiation by MALDI-TOF MS, which might represent a promising tool for the optimisation of infection control, individual patient management and large-scale epidemiological studies of public health relevance. The good correlation between phenotypic and genotypic features further corroborates phylogenetic relationships delineated by MLST.  相似文献   
92.
93.
94.
95.
96.
97.
BackgroundThe growth differentiation factor 15 (GDF-15) has been shown up-regulated in stress conditions and to have regulatory actions in myocyte hypertrophy. We hypothesized that GDF-15 could be related to disease severity and functional status in patients with hypertrophic cardiomyopathy (HCM).Methods and resultsWe performed a study which includes 102 consecutive outpatient HCM subjects, 73% males, aged 47.1 ± 14.6 years. A complete history and clinical examination was performed, including 12-lead electrocardiogram, echocardiography, symptom-limited treadmill exercise, 24-hour ECG-Holter monitoring, and magnetic resonance with Gadolinium. Several biomarkers, associated with myocardial remodeling and damage, were compared to GDF-15 levels. The assays were performed with commercial ELISAs or standardized methods when available. There was a significant association between GDF-15 levels and comorbidities, being higher in hypertension (p = 0.001), diabetes (p = 0.030), atrial fibrillation (p = 0.012), dyspnea (p = 0.020) and NYHA  II functional class (p = 0.037). GDF-15 levels were positively correlated with clinical variables (age, worse exercise capacity and mild renal dysfunction) and biomarkers of interstitial remodeling, such as metalloproteinase-2 (r: 0.40; p = 0.009), N-terminal pro-B-type natriuretic peptide (r: 0.28; p = 0.049), high-sensitivity troponin T (r: 0.30; p = 0.003) and von Willebrand factor (r: 0.33; p = 0.001). Multivariate analysis was assessed to estimate the involvement of these different factors in the GDF-15 levels, confirming the independent implication of severe dyspnea and functional status.ConclusionsThe present results show that higher levels of GDF-15 are associated to conditions of severe disease in HCM. Hence, GDF-15 is suggested as a novel marker related to the severity and could represent a further useful tool in monitoring functional capacity of HCM patients.  相似文献   
98.
99.

Background

Many women covered by the Spanish public health system also have an extra private insurance policy for gynecological examinations and routine annual mammography. We retrospectively analyzed the long-term survival rates in these patients when diagnosed with breast cancer.

Methods

We analyzed the survival and prognostic factors in patients diagnosed with breast cancer who were referred to a medical oncology unit for multidisciplinary treatment covered by private health insurance.

Results

Between 1994 and 2009, a total of 434 patients with breast tumor were analyzed: 33 in situ and 401 infiltrating. Among the infiltrating carcinomas, 38 were stage IV and 363 were stage I, II, or III. With a median follow-up of 62 months, the 5-year global survival rate was 91 %: 97 % for stage I, 94 % for stage II, and 77 % for stage III tumors. In the patients diagnosed by routine mammography, the 5-year survival rate was 96 %, compared with 86 % in those consulting their gynecologist after breast self-examination or for other symptoms (p = 0.0159). Seventy-four percent were treated conservatively and experienced better survival than the 26 % who underwent mastectomy (p = 0.0024). Patients with disease with positive hormone receptors had a better survival rate (p = 0.0264); hormone receptor status was the only independent prognostic factor in the Cox multivariate analysis. Postmenopausal patients who received adjuvant tamoxifen plus exemestane had a better prognosis than those who received tamoxifen alone (p = 0.0203).

Conclusions

Long-term survival rate was high in breast cancer patients with extra private insurance coverage. This is probably because disease was diagnosed at an early stage.  相似文献   
100.
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