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   7877篇
  免费   614篇
  国内免费   16篇
耳鼻咽喉   77篇
儿科学   381篇
妇产科学   188篇
基础医学   988篇
口腔科学   224篇
临床医学   1077篇
内科学   1337篇
皮肤病学   104篇
神经病学   704篇
特种医学   174篇
外国民族医学   3篇
外科学   801篇
综合类   100篇
一般理论   13篇
预防医学   1180篇
眼科学   90篇
药学   510篇
中国医学   16篇
肿瘤学   540篇
  2023年   72篇
  2022年   126篇
  2021年   280篇
  2020年   158篇
  2019年   261篇
  2018年   246篇
  2017年   199篇
  2016年   184篇
  2015年   199篇
  2014年   306篇
  2013年   414篇
  2012年   603篇
  2011年   603篇
  2010年   260篇
  2009年   275篇
  2008年   432篇
  2007年   470篇
  2006年   454篇
  2005年   451篇
  2004年   386篇
  2003年   328篇
  2002年   264篇
  2001年   110篇
  2000年   112篇
  1999年   88篇
  1998年   60篇
  1997年   47篇
  1996年   29篇
  1995年   37篇
  1992年   68篇
  1991年   52篇
  1990年   56篇
  1989年   62篇
  1988年   44篇
  1987年   50篇
  1986年   54篇
  1985年   39篇
  1984年   35篇
  1983年   35篇
  1982年   24篇
  1980年   25篇
  1979年   41篇
  1978年   34篇
  1977年   44篇
  1976年   26篇
  1975年   29篇
  1974年   27篇
  1973年   25篇
  1972年   37篇
  1970年   34篇
排序方式: 共有8507条查询结果,搜索用时 48 毫秒
91.
92.
The concentrations of tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and IL-1-β in tissue homogenates of gastric mucosal biopsy specimens, and in gastric juice samples from Helicobacter pylori-positive and -negative children, were determined. The study population comprised 30 children with recurrent abdominal pain attending upper gastrointestinal endoscopy. Of these patients 18 were infected with H. pylori. Cytokine concentrations in gastric biopsy homogenate supernatants and in gastric juice were measured by enzyme-linked immunosorbent assay (ELISA). TNF-α levels in gastric juice and in gastric biopsy homogenate supernatants in patients with H. pylori-positive gastritis were found to be significantly higher than those in children without H. pylori infection. IL-6 levels were also higher in H. pylori -infected subjects, but the difference in IL-6 concentrations measured in gastric juice and biopsy homogenate supernatants did not reach statistical significance. IL-1-β concentrations in both specimens showed no significant difference between the two groups of children. It was suggested that increased levels of inflammatory cytokines, especially TNF-α and IL-6 generated locally within the gastric mucosa might be implicated in the pathogenesis of H. pylori-associated gastritis in childhood.  相似文献   
93.
PURPOSE: Residents in rural communities in the United States, especially ethnic minority group members, have limited access to primary and specialty health care that is critical for diabetes management. This study examines primary and specialty medical care utilization among a rural, ethnically diverse, older adult population with diabetes. METHODS: Data were drawn from a cross-sectional face-to-face survey of randomly selected African American (n=220), Native American (n=181), and white (n=297) Medicare beneficiaries > or =65 years old with diabetes in 2 rural counties in central North Carolina. Participants were asked about utilization of a primary care doctor and of specialists (nutritionist, diabetes specialist, eye doctor, bladder specialist, kidney specialist, heart specialist, foot specialist) in the past year. FINDINGS: Virtually all respondents (99.0%) reported having a primary care doctor and seeing that doctor in the past year. About 42% reported seeing a doctor for diabetes-related care. On average, participants reported seeing 2 specialists in the past year, and 54% reported i seeing >1 specialist. Few reported seeing a diabetes specialist (5.7%), nutritionist (10.9%), or kidney specialist (17.5%). African Americans were more likely than others to report seeing a foot specialist (P < .01), while men were more likely than women to have seen bladder specialist (P = .02), kidney specialist (P = .001), and heart specialist (P = .004), after adjusting for potential confounders. Predictors of the number of specialists seen include gender, education, poverty status, diabetes medication use, and self-rated health. CONCLUSIONS: These data indicate low utilization of specialty diabetes care providers across ethnic groups and reflect the importance of primary care providers in diabetes care in rural areas.  相似文献   
94.
95.
96.
Severe congenital neutropenia (CN) is characterized by a maturation arrest of myelopoiesis at the promyelocyte stage. Treatment with pharmacological doses of recombinant human granulocyte colony-stimulating factor (rh-G-CSF) stimulates neutrophil production and decreases the risk of major infectious complications. However, approximately 15% of CN patients develop myeloid malignancies that have been associated with somatic mutations in the G-CSF receptor (G-CSFR) and RAS genes as well as with acquired monosomy 7. We report a CN patient with chronic myelomonocytic leukemia (CMML) who never received rh-G-CSF. Molecular analysis demonstrated a somatic G-CSFR mutation (C2390T), which led to expression of a truncated G-CSFR protein in the CMML. Normal G-CSFR expression was unexpectedly absent in primary and cultured CMML. In addition, CMML cells showed monosomy 7 and an oncogenic NRAS mutation. In vitro culture revealed a G-CSF-dependent proliferation of CMML cells, which subsequently differentiated along the monocytic/macrophage lineage. Our results provide direct evidence for the in vivo expression of a truncated G-CSFR in leukemic cells, which emerged in the absence of rh-G-CSF treatment and transduces proliferative signals.  相似文献   
97.
PURPOSE: Trastuzumab is effective in treating human epidermal growth factor receptor 2 (HER2) -positive breast cancer, but it increases frequency of cardiac dysfunction (CD) when used with or after anthracyclines. PATIENTS AND METHODS: National Surgical Adjuvant Breast and Bowel Project trial B-31 compared doxorubicin and cyclophosphamide (AC) followed by paclitaxel with AC followed by paclitaxel plus 52 weeks of trastuzumab beginning concurrently with paclitaxel in patients with node-positive, HER2-positive breast cancer. Initiation of trastuzumab required normal post-AC left ventricular ejection fraction (LVEF) on multiple-gated acquisition scan. If symptoms suggestive of congestive heart failure (CHF) developed, source documents were blindly reviewed by an independent panel of cardiologists to determine whether criteria were met for a cardiac event (CE), which was defined as New York Heart Association class III or IV CHF or possible/probable cardiac death. Frequencies of CEs were compared between arms. RESULTS: Among patients with normal post-AC LVEF who began post-AC treatment, five of 814 control patients subsequently had confirmed CEs (four CHFs and one cardiac death) compared with 31 of 850 trastuzumab-treated patients (31 CHFs and no cardiac deaths). The difference in cumulative incidence at 3 years was 3.3% (4.1% for trastuzumab-treated patients minus 0.8% for control patients; 95% CI, 1.7% to 4.9%). Twenty-seven of the 31 patients in the trastuzumab arm have been followed for > or = 6 months after diagnosis of a CE; 26 were asymptomatic at last assessment, and 18 remained on cardiac medication. CHFs were more frequent in older patients and patients with marginal post-AC LVEF. Fourteen percent of patients discontinued trastuzumab because of asymptomatic decreases in LVEF; 4% discontinued trastuzumab because of symptomatic cardiotoxicity. CONCLUSION: Administering trastuzumab with paclitaxel after AC increases incidence of CHF and lesser CD. Potential cardiotoxicity should be carefully considered when discussing benefits and risks of this therapy.  相似文献   
98.
99.
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