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   266396篇
  免费   32332篇
  国内免费   8645篇
耳鼻咽喉   2119篇
儿科学   2498篇
妇产科学   5708篇
基础医学   22142篇
口腔科学   3231篇
临床医学   22238篇
内科学   25508篇
皮肤病学   1718篇
神经病学   9514篇
特种医学   7933篇
外国民族医学   254篇
外科学   33117篇
综合类   36375篇
现状与发展   45篇
一般理论   3篇
预防医学   19175篇
眼科学   803篇
药学   21436篇
  234篇
中国医学   7181篇
肿瘤学   86141篇
  2024年   580篇
  2023年   5080篇
  2022年   7636篇
  2021年   13635篇
  2020年   12757篇
  2019年   11201篇
  2018年   10796篇
  2017年   11259篇
  2016年   12165篇
  2015年   13760篇
  2014年   21044篇
  2013年   21176篇
  2012年   17436篇
  2011年   17953篇
  2010年   13254篇
  2009年   13365篇
  2008年   13725篇
  2007年   12834篇
  2006年   11422篇
  2005年   9403篇
  2004年   7817篇
  2003年   6593篇
  2002年   5475篇
  2001年   4956篇
  2000年   4120篇
  1999年   3502篇
  1998年   3067篇
  1997年   2782篇
  1996年   2260篇
  1995年   2134篇
  1994年   1848篇
  1993年   1496篇
  1992年   1345篇
  1991年   1252篇
  1990年   976篇
  1989年   882篇
  1988年   807篇
  1987年   734篇
  1986年   615篇
  1985年   825篇
  1984年   687篇
  1983年   435篇
  1982年   460篇
  1981年   428篇
  1980年   386篇
  1979年   251篇
  1978年   204篇
  1977年   178篇
  1976年   138篇
  1975年   68篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
92.

Objective

Comparative survival between neoadjuvant chemotherapy and adjuvant chemotherapy for patients with cT2-4N0-1M0 non–small cell lung cancer has not been extensively studied.

Methods

Patients with cT2-4N0-1M0 non–small cell lung cancer who received platinum-based chemotherapy were retrospectively identified. Exclusion criteria included stage IV disease, induction radiotherapy, and targeted therapy. The primary end point was disease-free survival. Secondary end points were overall survival, chemotherapy tolerance, and ability of Response Evaluation Criteria In Solid Tumors response to predict survival. Survival was estimated using the Kaplan–Meier method, compared using the log-rank test and Cox proportional hazards models, and stratified using matched pairs after propensity score matching.

Results

In total, 330 patients met the inclusion criteria (n = 92/group after propensity-score matching; median follow-up, 42 months). Five-year disease-free survival was 49% (95% confidence interval, 39-61) for neoadjuvant chemotherapy versus 48% (95% confidence interval, 38-61) for adjuvant chemotherapy (P = .70). On multivariable analysis, disease-free survival was not associated with neoadjuvant chemotherapy or adjuvant chemotherapy (hazard ratio, 1.1; 95% confidence interval, 0.64-1.90; P = .737), nor was overall survival (hazard ratio, 1.21; 95% confidence interval, 0.63-2.30; P = .572). The neoadjuvant chemotherapy group was more likely to receive full doses and cycles of chemotherapy (P = .014/0.005) and had fewer grade 3 or greater toxicities (P = .001). Response Evaluation Criteria In Solid Tumors response to neoadjuvant chemotherapy was associated with disease-free survival (P = .035); 15% of patients receiving neoadjuvant chemotherapy (14/92) had a major pathologic response.

Conclusions

Timing of chemotherapy, before or after surgery, is not associated with an improvement in overall or disease-free survival among patients with cT2-4N0-1M0 non–small cell lung cancer who undergo complete surgical resection.  相似文献   
93.
Breast carcinoma is a major cause of morbidity and mortality in women. The study of bone pathologies presents considerable potential in anthropology, paleopathology, forensic science and medicine. In this paper, we present and discuss metastatic lesions found in the skeletons of known individuals from the CAL Milano Cemetery Skeletal Collection, clinically diagnosed with breast cancer during life. Fourteen skeletons from a contemporary and identified collection were macroscopically studied and metastases were identified by comparison with clinical literature. As a result, bone metastases were observed in 43% of the study sample. They were located most commonly on the ribs (28.1%), pelvic girdle (19.8%), vertebrae (15.6%), skull (15.6%), scapulae (10.2%) as well as proximal segment of the femora (8.4%) and humeri (2.4%) respectively, favoring sites of high vascularization. The majority of the lesions were osteolytic, although osteoblastic and mixed metastases did occur. Osteolytic metastases appear as coalescent porosity or round to oval perforating lesions on bones with denticulated margins and pitted surrounding bone, whereas osteoblastic metastases thickened the existing trabecula (spongiosclerosis). Mixed metastases were perforating lytic lesions exposing the osteoblastic activity in the underlying trabecular bone. These results, consistent with the data from the literature, strengthen the diagnostic criteria for metastases and illustrate the aspect of bone metastases in breast carcinoma.  相似文献   
94.
目的:探讨3D-CRT 低剂量区 V5体积的大小对非小细胞肺癌患者肺功能的影响。方法:收集我院肿瘤科2014年4月~2015年10月收治的46例首次行三维适形放射治疗且顺利完成治疗的非小细胞肺癌患者,对每例患者分别在治疗前以及治疗后的1、3个月进行肺功能检测,分析3D-CRT 低剂量区 V5体积的大小与肺功能变化之间的关系。结果:放疗后1个月的 FEV1%、FVC%值明显高于放疗前且差异均具有显著性。放疗后1个月、3个月的 DLCO%值明显低于放疗前,且放疗前的与放疗后3个月的差异具有显著性;V5≦45%、45%55%三组放疗前后的 FEV1%值和 FVC%值比较差异均不具有显著性。V5≦45%、45%55%三组放疗前后的 DLCO%值均呈逐渐下降趋势,且 V5>55%组的放疗前后 DLCO%值比较差异具有显著性。而 V5≦45%组和45%55%时,DLCO%值降低的趋势更加显著。  相似文献   
95.
Paraneoplastic pemphigus is a relatively rare but significant acquired autoimmune mucocutaneous disorder that is characterised by diffuse erythema, painful blistering and sores of the skin and mucus membranes. The underlying pathogenesis is believed to be triggered by altered immune system in response to underlying neoplasm. The manifestations can predate, occur at the same time or after the diagnosis of cancer. Associations with gastric cancer have only been reported twice. A 78-year-old lady presented with a month’s history of extensive skin lesions that started off as bullous lesions and biopsy revealed bullous pemphigus. Endoscopy for anemia revealed gastric cancer. This case reinforced the need to consider underlying malignancy in elderly patient with new onset dermatological presentation.  相似文献   
96.
目的 探讨不同非密闭雾化方式在不合作患儿接受布地奈德雾化治疗中的应用效果。方法 选取本院门诊270例3岁以下使用布地奈德雾化治疗的患儿,采用随机数字表法将患儿分为Pari雾化系统、Philips雾化系统及Salter雾化系统3个治疗组,毎组90例,各组又依据面罩距离面部0 cm、2 cm、4 cm分为3个小组,毎组30例,分别测量各组雾化气流流速及吸入雾化颗粒量占总雾化颗粒量的比例。采用方差分析及Bonferroni进行统计分析。结果 雾化气流流速及雾化吸入量在不同雾化系统组间差异有统计学意义(P<0.05)。在3种距离下,Pari系统均能使患儿吸入最多量的雾化颗粒,其次是Salter系统,再是Philips系统,与此相反,气流流速Pari系统最低。Pari系统离开面部4 cm及Salter系统离开面部2 cm的吸入量均高于Philips系统0 cm的吸入量。结论 选择合适的非密闭雾化系统方式,是提高不合作患儿布地奈德雾化治疗的有效方式。  相似文献   
97.
The Combined Aerobic and Resistance Exercise (CARE) Trial compared different types and doses of exercise performed during breast cancer chemotherapy. Here, we report the longer-term follow-up of patient-reported outcomes, health-related fitness and exercise behavior at 6, 12 and 24 months postintervention. A multicenter trial in Canada randomized 301 breast cancer patients initiating chemotherapy to thrice weekly, supervised exercise consisting of a standard dose of 25–30 min of aerobic exercise (STAN; n = 96), a higher dose of 50–60 min of aerobic exercise (HIGH; n = 101) or a combined dose of 50–60 min of aerobic and resistance exercise (COMB; n = 104) performed for the duration of chemotherapy (median of 17 weeks). Primary outcomes were patient-reported outcomes including quality of life, cancer-related symptoms and psychosocial outcomes. Secondary outcomes were objective health-related fitness (assessed at 12 months only) and self-reported exercise behavior. A total of 269 (89.4%) participants completed patient-reported outcomes at all three follow-up time points and 263 (87.4%) completed the health-related fitness assessment at 12-month follow-up. COMB was significantly superior to (i) STAN for sleep quality at 6-month follow-up (p = 0.027); (ii) HIGH for upper body muscular endurance at 12-month follow-up (p = 0.020); and (iii) HIGH for meeting the resistance exercise guideline at 6-month follow-up (p = 0.006). Moreover, self-reported meeting of the combined exercise guideline during follow-up was significantly associated with better patient-reported outcomes and health-related fitness. Performing combined exercise during and after breast cancer chemotherapy may result in better longer-term patient-reported outcomes and health-related fitness compared to performing aerobic exercise alone.  相似文献   
98.
Nidogen 1 (NID1) is a glycoprotein found in basement membranes involved in cross-linking collagen IV and laminin. The role of NID in breast cancer has only been evaluated in a small number of studies and the findings of these studies have been inconsistent. Our previous work revealed that highly tumorigenic murine mammary tumor cells express high levels of Nid1 while weakly tumorigenic mammary tumor cells express low levels of Nid1. To investigate Nid1, two stable knockdown lines were created, and Nid1 knockdown was confirmed at both the mRNA and protein level. Nid1 knockdown significantly reduced cell proliferation and migration/invasion and these reductions in proliferation and migration/invasion could be rescued by conditioned media containing NID1 protein. The reduced migration/invasion observed in the Nid1 knockdown cells was not associated with significant alterations in the epithelial gene Cdh1 or the mesenchymal genes Snai1, Snai2, Twist1, Twist2, Zeb1 and Zeb2. Therefore, suppression of Nid1 expression reduces proliferation and migration/invasion in claudin-low murine mammary tumor cells.  相似文献   
99.
100.
目的:构建基于SERVQUAL模型的医养结合型养老机构卫生服务质量评价指标体系。方法:围绕医养结合型养老机构卫生服务的概念、特性、内涵、内容等,采用文献研究法、半结构式访谈法、Delphi—AHP法等定性与定量相结合的研究方法,构建指标体系并确定指标权重。结果:构建了具有7个一级指标,27个二级指标和77个三级指标的养老机构卫生服务质量评价指标体系。指标体系三轮咨询专家权威系数Cr均高于0.84,专家综合权威性系数均高于0.83;总体专家协调系数Kendall W第一、二轮为0.309,第三轮为0.706,且均通过显著性检验;内容效度指数I-CVI介于0.90~1.00之间,S-CVI为0.94,kappa值均高于0.74;信度系数Cronbachα总体为0.972,各维度Cronbachα系数在0.792~0.921之间。评价指标体系具有较好的稳定性、可靠性和一致性。结论:本研究建立的评价指标体系有利于医养结合型养老机构全面建立贴近老年人卫生服务需求的内设医疗机构,改善机构内卫生服务质量。在对指标体系进行应用时,可转化为机构中老年人对各指标项目的感受(P)与期望(E),以两者的差值(P-E)代表机构的卫生服务质量。根据专家赋权结果,应重点加强医养结合养老机构对可靠性、有效性、经济性等指标项目的建设。  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