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   4489篇
  免费   336篇
  国内免费   14篇
耳鼻咽喉   35篇
儿科学   169篇
妇产科学   97篇
基础医学   520篇
口腔科学   69篇
临床医学   611篇
内科学   822篇
皮肤病学   50篇
神经病学   434篇
特种医学   100篇
外科学   682篇
综合类   65篇
一般理论   26篇
预防医学   532篇
眼科学   32篇
药学   275篇
中国医学   8篇
肿瘤学   312篇
  2023年   62篇
  2022年   103篇
  2021年   278篇
  2020年   124篇
  2019年   236篇
  2018年   248篇
  2017年   150篇
  2016年   132篇
  2015年   134篇
  2014年   183篇
  2013年   260篇
  2012年   340篇
  2011年   401篇
  2010年   174篇
  2009年   150篇
  2008年   246篇
  2007年   214篇
  2006年   198篇
  2005年   202篇
  2004年   175篇
  2003年   133篇
  2002年   120篇
  2001年   40篇
  2000年   32篇
  1999年   24篇
  1998年   27篇
  1997年   17篇
  1996年   18篇
  1995年   17篇
  1994年   13篇
  1993年   17篇
  1992年   28篇
  1991年   27篇
  1990年   35篇
  1989年   20篇
  1988年   21篇
  1987年   28篇
  1986年   23篇
  1985年   12篇
  1984年   12篇
  1983年   8篇
  1982年   14篇
  1981年   11篇
  1980年   9篇
  1979年   19篇
  1978年   9篇
  1977年   8篇
  1976年   12篇
  1971年   10篇
  1970年   10篇
排序方式: 共有4839条查询结果,搜索用时 15 毫秒
71.
The progress with intensive chemotherapy and supportive care measures has improved survival in patients with newly diagnosed acute myeloid leukemia (AML). Given the recent development of effective low intensity therapies, an optimal decision on the therapy intensity may improve survival through the avoidance of early mortality. We reviewed the outcome of 3728 patients with newly diagnosed AML who received intensive chemotherapy between August 1980 and May 2020. Intensive chemotherapy was defined as a cumulative cytarabine dose ≥ 700 mg/m2 during induction therapy. We divided the whole cohort into a training and validation group at a 3:1 ratio. The population was divided into a training (2790 patients) and a validation cohort (938 patients). The median age was 55 years (range, 15-99). Among them, 442 patients (12%) had core-binding factor AML. Binary logistic regression identified older age, worse performance status, hyperbilirubinemia, elevated creatinine, hyperuricemia, cytogenetic abnormalities other than CBF and -Y, and pneumonia as adverse prognostic factors for an early 4-week mortality. This risk classification for early mortality was verified in the validation cohort of patients. In the validation cohort of more recently treated patients from 2000 to 2017, the 4-week mortality rates with intensive chemotherapy were 2%, 14%, and 50% in the low-, high-, and very high-risk group, respectively. The mortality rates with low intensity therapies were 3%, 9%, and 20%, respectively. The risk classification guides treatment intensity by the assessment of age, frailty, organ dysfunction, cytogenetic abnormality, and infection to avoid early mortality.  相似文献   
72.

Community implementation of evidence-based practices (EBPs) for Attention Deficit/Hyperactivity Disorder (ADHD) is greatly lacking. A recent randomized community-based trial of an EBP for ADHD (Supporting Teens’ Autonomy Daily; STAND) demonstrated suboptimal implementation and effectiveness outcomes. In the present study, we conducted an Innovation Tournament (IT) with agency staff stakeholders (N?=?26) to identify barriers to successful implementation of STAND and implementation strategies for a revised service delivery model. We conducted member-checking of agency staff-generated ideas with parents (N?=?226) and subsequent querying of additional parent (N?=?226) and youth-generated (N?=?205) strategies to improve care. Go-Zone plots were utilized to identify strategies with the highest feasibility and importance. Practical barriers (i.e., transportation, scheduling difficulties) and parent/youth engagement were the most commonly cited obstacles to successful implementation of STAND in community contexts. Eighteen “winning” implementation strategies were identified that survived member checking. These were classified as train and educate stakeholders (n?=?5; e.g., train agency supervisors to deliver supervision, digitize treatment materials and trainings), engage consumers (n?=?9; e.g., begin treatment with rapport building sessions, increase psychoeducation), provide interactive assistance (n?=?2; e.g., add group supervision, increase roleplay in supervision), and use of evaluative/iterative strategies (n?=?2; e.g., perform fidelity checks, supervisor review of session recordings). Parents and youth desired longer duration of treatment and increased focus on maintenance. Strategies will be developed and tested as part of a pilot effectiveness trial designed to refine STAND’s service delivery model.

Trial Registration NCT02694939 www.clinicaltrials.gov

  相似文献   
73.
74.
75.
76.
77.
ObjectivesIntravenous (IV) tissue plasminogen activator (tPA) should be given to patients with acute ischemic stroke (AIS) and avoided in stroke mimics (SM). Select use of emergency brain magnetic resonance imaging (eMRI-brain) in stroke-alerts aids diagnosis, but accepted utilization criteria for eMRI-brain do not currently exist. We developed criteria for eMRI-brain and report the yield of eMRI-brain in stroke-alert patients.Materials and MethodsWe developed three history-based criteria for performing eMRI-brain during stroke-alerts: (1) history of previous similar deficits, (2) change in consciousness at onset of symptoms, (3) symptom presentation consistent with migraine aura. We then performed a retrospective chart review of patients who presented as a stroke-alert over a 5-year period and determined how these criteria affected administration of IV tPA to AIS and SM patients.ResultsAmong 3,512 stroke-alerts, 230 (8.1%) patients met our criteria for eMRI-brain exams: 217 (92.6%) had SM and 17 (7.4%) had AIS. Our IV tPA decision-making analysis showed that based on eMRI-brain IV tPA was less frequently administered to SM patients (PCC-0.841, p=0.036) with less failures to administer IV tPA to patients with AIS (PCC -0.907, p-value=0.013, Pearson correlation coefficient). No patients became ineligible for IV tPA due to MRI-related time delays.ConclusionsOur history based criteria for performing eMRI-brain during stroke-alerts show a high yield of stroke mimics. Selective eMRI-brain improves decision-making accuracy regarding IV tPA administration.  相似文献   
78.
79.
The proprotein convertases (PCs) furin and PACE4 process numerous substrates involved in tumor growth, invasion, and metastasis. We have previously shown that PCs increase the susceptibility to chemical skin carcinogenesis. Because of the human relevancy of UV radiation in the etiopathogenesis of human skin cancer, we investigated whether or not transgenic mice overexpressing either furin alone or both furin and PACE4 show increased susceptibility to UV carcinogenesis. After backcrossing our previously described furin and PACE4 transgenic lines, targeted to the epidermis, into a SKH-1 background, we exposed both single and double transgenic mice to UV radiation for 34 weeks. The results showed an increase in squamous cell carcinoma (SCC) multiplicity of approximately 70% in the single furin transgenic mouse line SF47 (P < .002) and a 30% increase in the other single transgenic line SF49 when compared to wild-type (WT) SKH-1 mice. Interestingly, there was also an increase in the percentage of high histologic grade SCCs in the transgenic lines compared to the WT mice, i.e., WT = 9%, SF47 = 15%, and SF49 = 26% (P < .02). Targeting both furin and PACE4 to the epidermis in double transgenic mice did not have an additive effect on tumor incidence/multiplicity but did enhance the tumor histopathologic grade, i.e., a significant increase in higher grade SCCs was seen in the bigenic mouse line SPF47 (P < .02). Thus, we observed an increased susceptibility to UV in single furin transgenic mice that was not substantially enhanced in the double furin/PACE4 transgenic mice.  相似文献   
80.
Pancreatic cancer is the fourth leading cause of cancer deaths in the USA. Although some patients will present with premalignant pancreatic lesions (i.e., intraductal papillary mucinous neoplasms) or localized tumors amenable to curative resection, the majority of patients will unfortunately present with technically unresectable or metastatic disease. This review of the recent medical literature will discuss the optimal work-up and management of premalignant pancreatic lesions and the surgical management of localized, borderline resectable, and locally advanced (i.e., unresectable) pancreatic tumors. It will focus on new criteria used to define surgical “resectability,” the significance and clinical impact of surgical margins, the role of multimodality therapy in the management of patients with borderline resectable or locally advanced tumors, the role of surgery for local or distant recurrence, and minimally invasive surgical approaches.  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