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   32397篇
  免费   2079篇
  国内免费   259篇
耳鼻咽喉   434篇
儿科学   591篇
妇产科学   489篇
基础医学   3986篇
口腔科学   1544篇
临床医学   2664篇
内科学   8680篇
皮肤病学   391篇
神经病学   3301篇
特种医学   1315篇
外科学   5229篇
综合类   93篇
一般理论   6篇
预防医学   1312篇
眼科学   538篇
药学   1695篇
中国医学   72篇
肿瘤学   2395篇
  2023年   333篇
  2022年   275篇
  2021年   1095篇
  2020年   745篇
  2019年   1022篇
  2018年   1205篇
  2017年   956篇
  2016年   1067篇
  2015年   1130篇
  2014年   1459篇
  2013年   1779篇
  2012年   2780篇
  2011年   2678篇
  2010年   1499篇
  2009年   1370篇
  2008年   2145篇
  2007年   2256篇
  2006年   2031篇
  2005年   1844篇
  2004年   1643篇
  2003年   1495篇
  2002年   1295篇
  2001年   256篇
  2000年   233篇
  1999年   220篇
  1998年   192篇
  1997年   170篇
  1996年   125篇
  1995年   136篇
  1994年   123篇
  1993年   105篇
  1992年   114篇
  1991年   93篇
  1990年   79篇
  1989年   54篇
  1988年   85篇
  1987年   61篇
  1986年   44篇
  1985年   63篇
  1984年   52篇
  1983年   43篇
  1982年   43篇
  1981年   28篇
  1980年   24篇
  1979年   41篇
  1978年   30篇
  1977年   22篇
  1974年   21篇
  1973年   31篇
  1972年   26篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
71.
72.
Pancreatic cystic neoplasms(PCNs) are a high prevalence disease. It is estimated that about 20% of the general population is affected by PCNs. Some of those lesions can progress till cancer, while others behave in a benign fashion. In particular intraductal papillary mucinousneoplasms of the pancreas can be considered as the pancreatic analogon to colonic polyps. Treatment of these precursor lesions at an early stage can potentially reduce pancreas cancer mortality and introduce a new "era" of preemptive pancreatic surgery. However, only few of those lesions have an aggressive behavior. The accuracy of preoperative diagnosis, i.e., the distinction between the various PCNs is around 60%, and the ability to predict the future outcome is also less accurate. For this reason, a significant number of patients are currently over-treated with an unnecessary, high-risk surgery. Furthermore, the majority of patients with PCN are on life-long follow-up with imaging modality, which has huge cost implications for the Health Care System for limited benefits considering that a significant proportion of PCNs are or behave like benign lesions. The current guidelines for the diagnosis and management of PCNs are more based on expert opinion than on evidence. For all those reasons, the management of cystic tumors of the pancreas remains a controversial area of pancreatology. On one hand, the detection of PCNs and the surgical treatment of pre-cancerous neoplasms can be considered a big opportunity to reduce pancreatic cancer related mortality. On the other hand, PCNs are associated with a considerable risk of under- or over- treatment of patients and incur high costs for the Health Care System.  相似文献   
73.
74.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
75.
76.
77.
BackgroundThere is poor data on the prognostic role of Comprehensive Geriatric Assessment (CGA) in older patients with metastatic renal cell carcinoma (mRCC) treated with first line Tyrosine Kinase Inhibitors (TKIs).Materials and MethodsWe retrospectively reviewed the clinical charts of mRCC patients older than 70 years treated at our Institute with first-line Sunitinib or Pazopanib for at least 6 months. Every patient received a CGA at baseline and was identified as fit, vulnerable or frail according to Balducci's Criteria. We then assessed the impact of CGA category on survival, disease control and tolerability of TKIs.ResultsWe identified 86 eligible patients. Median age: 74.5 years, 56% males; 45.4% were fit, 37.2% vulnerable and 17.4% frail at CGA. There were no significant differences in the rate of Grade (G)1–2 and G3-4 toxicities, dose reduction rates, PFS and OS between Sunitinib and Pazopanib. Fit, vulnerable and frail patients achieved significantly different median PFS (18.9 vs 11.2 vs 5.1 months; p < 0.001) and OS (35.5 vs 14.6 vs 10.9 months; p < 0.001). Patients categorized as fit had higher chance of receiving a second-line treatment (66.6% vs 28.9% in vulnerable/frail; p = 0.002). The incidence of G3/4 events was significantly lower in the fit subgroup (19% vs 45% in vulnerable/frail; p = 0.0025).ConclusionsIn our retrospective single-center experience, CGA could accurately discriminate patients with higher risk of experiencing G3/4 toxicities, shorter PFS, and lower chance of receiving a second line treatment. CGA strongly impacted on OS, independently from International mRCC Database Consortium (IMDC) classification.  相似文献   
78.
79.
IntroductionBreast cancer survivors are at increased risk of developing unrelated primary cancers, particularly lung cancer. Evidence indicates that sex hormones as well as a deregulation of DNA-repair pathways may contribute to lung cancer onset. We investigated whether the hormone status and expression of markers involved in DNA repair (BRCA1/2, ERCC1, and P53R2), synthesis (TS and RRM1), and cell division (TUBB3) might be linked to lung cancer risk.Patients and MethodsThirty-seven breast cancer survivors with unrelated lung cancer and 84 control subjects comprising women with breast cancer (42/84) or lung cancer (42/84) were enrolled. Immunohistochemistry on tumor tissue was performed. Geometric mean ratio was used to assess the association of marker levels with patient groups.ResultsEstrogen receptor was expressed in approximately 90% of the breast cancer group but was negative in the majority of the lung cancer group, a result similar to the lung cancer control group. Likewise, ER isoform β was weakly expressed in the lung cancer group. Protein analysis of breast cancer versus control had a significantly lower expression of BRCA1, P53R2, and TUBB3. Likewise, a BRCA1 reduction was observed in the lung cancer group concomitant with a BRCA2 increase. Furthermore, BRCA2 and TUBB3 increased in ipsilateral lung cancer in women who had previously received radiotherapy for breast cancer.ConclusionThe decrease of DNA-repair proteins in breast cancer could make these women more susceptible to therapy-related cancer. The increase of BRCA2 and TUBB3 in lung cancer from patients who previously received radiotherapy for breast cancer might reflect a tissue response to exposure to ionizing radiation.  相似文献   
80.
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