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   2352428篇
  免费   175431篇
  国内免费   3360篇
耳鼻咽喉   32109篇
儿科学   75990篇
妇产科学   62877篇
基础医学   348978篇
口腔科学   63805篇
临床医学   211656篇
内科学   458736篇
皮肤病学   51914篇
神经病学   185769篇
特种医学   88285篇
外国民族医学   489篇
外科学   355026篇
综合类   47521篇
现状与发展   12篇
一般理论   848篇
预防医学   182763篇
眼科学   54429篇
药学   175591篇
  10篇
中国医学   4582篇
肿瘤学   129829篇
  2021年   19112篇
  2019年   19628篇
  2018年   27186篇
  2017年   20454篇
  2016年   22861篇
  2015年   25772篇
  2014年   36237篇
  2013年   54163篇
  2012年   74989篇
  2011年   79753篇
  2010年   47247篇
  2009年   44719篇
  2008年   74950篇
  2007年   79800篇
  2006年   80619篇
  2005年   78151篇
  2004年   74699篇
  2003年   72001篇
  2002年   69668篇
  2001年   109016篇
  2000年   111717篇
  1999年   93789篇
  1998年   27106篇
  1997年   23756篇
  1996年   24130篇
  1995年   22794篇
  1994年   20954篇
  1993年   19767篇
  1992年   72233篇
  1991年   70279篇
  1990年   68600篇
  1989年   65900篇
  1988年   60499篇
  1987年   59301篇
  1986年   55393篇
  1985年   53148篇
  1984年   39424篇
  1983年   33453篇
  1982年   19888篇
  1979年   35931篇
  1978年   25697篇
  1977年   21270篇
  1976年   20354篇
  1975年   21859篇
  1974年   26205篇
  1973年   24859篇
  1972年   23243篇
  1971年   22075篇
  1970年   20281篇
  1969年   19356篇
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
161.
Hypertrophic lichen planus (HLP) is a T‐cell‐mediated process typically presenting with hypertrophic or verrucous plaques on the lower limbs. We report the case of a 24‐year‐old woman with a history of HLP since age 3 years presenting with rapid malignant transformation of one lesion into a large squamous cell carcinoma (SCC). Subsequent examination revealed progressive, widespread metastatic involvement, and the patient ultimately died from her disease. SCC associated with HLP is rare, with a review of the literature revealing fewer than 50 cases. This case highlights the need to be aware of suspicious changes in HLP and to educate patients as to when to be reevaluated.  相似文献   
162.
163.
Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial‐ and muscular‐dependent pathways. This was associated with an enhanced nitric oxide‐dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN.  相似文献   
164.
165.
Thyroid diseases are common, and use of levothyroxine is increasing worldwide. We investigated the influence of gender, race and socioeconomic status on the diagnosis and treatment of thyroid disorders using data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), a multicenter cohort study of civil servants (35-74 years of age) from six Brazilian cities. Diagnosis of thyroid dysfunction was by thyrotropin (TSH), and free thyroxine (FT4) if TSH was altered, and the use of specific medications. Multivariate logistic regression models were constructed using overt hyperthyroidism/hypothyroidism and levothyroxine use as dependent variables and sociodemographic characteristics as independent variables. The frequencies of overt hyper- and hypothyroidism were 0.7 and 7.4%, respectively. Using whites as the reference ethnicity, brown, and black race were protective for overt hypothyroidism (OR=0.76, 95%CI=0.64-0.89, and OR=0.53, 95%CI=0.43-0.67, respectively, and black race was associated with overt hyperthyroidism (OR=1.82, 95%CI=1.06-3.11). Frequency of hypothyroidism treatment was higher in women, browns, highly educated participants and those with high net family incomes. After multivariate adjustment, levothyroxine use was associated with female gender (OR=6.06, 95%CI=3.19-11.49) and high net family income (OR=3.23, 95%CI=1.02-10.23). Frequency of hyperthyroidism treatment was higher in older than in younger individuals. Sociodemographic factors strongly influenced the diagnosis and treatment of thyroid disorders, including the use of levothyroxine.  相似文献   
166.
Coronavirus disease 2019 (COVID-19) has resulted in many challenges in patient care, especially among high-risk populations such as heart transplant recipients. Patients with heart transplant experience a significantly higher mortality rate with COVID-19 infection, and management is based on extrapolation from clinical trials done on nontransplant patients and from clinical experience. Here we report 4 cases of patients with heart transplant who presented with COVID-19 infection in late 2020. Patients presented with symptoms similar to those seen in the general population. All 4 patients were admitted to the hospital, and they were all treated with dexamethasone. In addition, 2 patients received remdesivir. Immunosuppressive medications were adjusted to maintain adequate levels of immunosuppression but at the same time allow for an adequate immune response against the infection. All patients were discharged alive from the hospital. We then performed a literature review on studies that included heart transplant patients who developed the infection and developed suggestions for a standardized management approach, which we share in this article.  相似文献   
167.
Journal of Thrombosis and Thrombolysis - Amniotic fluid embolism (AFE) is a catastrophic condition in the peripartum period and still remains as a leading cause of maternal death. Although over 80%...  相似文献   
168.
PurposeOur purpose was to determine the effect of chemoradiotherapy (CRT) on patient-reported quality of life (QOL) for patients with intact pancreas cancer.Methods and MaterialsWe reviewed a prospective QOL registry for patients with intact, clinically localized pancreatic ductal adenocarcinoma treated with CRT between June 2015 and November 2018. QOL was assessed pre-CRT (immediately before CRT, after neoadjuvant chemotherapy) and at the completion of CRT with the Functional Assessment of Cancer Therapy-Hepatobiliary (FACT-Hep) and its component parts: FACT-General (FACT-G) and hepatobiliary cancer subscore (HCS). A minimally important difference from pre-CRT was defined as ≥ 6, 5, and 8 points for FACT-G, HCS, and FACT-Hep, respectively.ResultsOf 157 patients who underwent CRT, 100 completed both pre- and post-CRT surveys and were included in the primary analysis. Median age at diagnosis was 65 years (range, 23-90). National Comprehensive Cancer Network resectability status was resectable (3%), borderline resectable (40%), or locally advanced (57%). Folinic acid, 5-fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX) (75%) or gemcitabine and nab-paclitaxel (42%) were given for a median of 6 cycles (range, 0-42) before CRT. Radiation therapy techniques included 3-dimensional conformal (22%), intensity modulated photon (55%), and intensity modulated proton (23%) radiation therapy to a median dose of 50 Gy (range, 36-62.5). Concurrent chemotherapy was most commonly capecitabine (82%). Sixty-three patients (63%) had surgery after CRT. The mean decline in FACT-G, HCS subscale, and FACT-Hep from pre- to post-CRT was 3.5 (standard deviation [SD], 13.7), 1.7 (SD 7.8), and 5.2 (SD 19.4), respectively. Each of these changes were statistically significant, but did not meet the minimally important difference threshold. Pancreatic head tumor location was associated with decline in FACT-Hep. Nausea was the toxicity with the greatest increase from pre- to post-CRT by both physician-assessment and patient-reported QOL.ConclusionsFor patients with intact pancreatic adenocarcinoma, modern CRT is well tolerated with minimal decline in QOL during treatment.  相似文献   
169.
170.
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