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   160453篇
  免费   10870篇
  国内免费   640篇
耳鼻咽喉   1774篇
儿科学   3929篇
妇产科学   2624篇
基础医学   21097篇
口腔科学   3435篇
临床医学   15650篇
内科学   34072篇
皮肤病学   3280篇
神经病学   14756篇
特种医学   7052篇
外国民族医学   14篇
外科学   25583篇
综合类   1969篇
一般理论   109篇
预防医学   11849篇
眼科学   3347篇
药学   10198篇
中国医学   238篇
肿瘤学   10987篇
  2023年   899篇
  2022年   1513篇
  2021年   3433篇
  2020年   2109篇
  2019年   3158篇
  2018年   3635篇
  2017年   2832篇
  2016年   3190篇
  2015年   3632篇
  2014年   5156篇
  2013年   6930篇
  2012年   10475篇
  2011年   11125篇
  2010年   6393篇
  2009年   6075篇
  2008年   9823篇
  2007年   10277篇
  2006年   10197篇
  2005年   10242篇
  2004年   9390篇
  2003年   8692篇
  2002年   8336篇
  2001年   2173篇
  2000年   1862篇
  1999年   2160篇
  1998年   1946篇
  1997年   1569篇
  1996年   1350篇
  1995年   1259篇
  1994年   1144篇
  1993年   1031篇
  1992年   1309篇
  1991年   1202篇
  1990年   1047篇
  1989年   979篇
  1988年   918篇
  1987年   897篇
  1986年   891篇
  1985年   875篇
  1984年   929篇
  1983年   801篇
  1982年   963篇
  1981年   867篇
  1980年   730篇
  1979年   656篇
  1978年   646篇
  1977年   536篇
  1976年   515篇
  1974年   513篇
  1973年   449篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
OBJECTIVE: The authors described the influence of specific medical conditions on clinical remission and response of major depression (MDD) in a clinical trial evaluating a care-management intervention among older primary-care patients. METHODS: Adults age 60 years and older were randomly selected and screened for depression. Participants were randomly assigned to Usual Care or to an Intervention with a depression care-manager offering algorithm-based care for MDD. In all, 324 adults meeting criteria for MDD were included in these analyses. Remission and response was defined by a score on the Hamilton Rating Scale for Depression <10 and by a decrease from baseline of > or =50%, respectively. Medical comorbidity was ascertained through self-report. Cognitive impairment was defined by a score <24 on the Mini-Mental State Exam (MMSE). RESULTS: In Usual Care, rates of remission were faster in persons who reported atrial fibrillation (AF) than in persons who did not report AF and slower in persons who reported chronic pulmonary disease than in persons who did not report chronic pulmonary disease; rates of response were less stable in persons with MMSE <24 than in those with MMSE > or =24. In the Intervention condition, none of the specific chronic medical conditions were significantly associated with outcomes for MDD. CONCLUSIONS: Because disease-specific findings were observed in persons who received Usual Care but not in persons who received more intensive treatment in the Intervention condition, our results suggest that the association of medical comorbidity and treatment outcomes for MDD may be determined by the intensity of treatment for depression.  相似文献   
103.
Mechanical airway obstruction secondary to retropharyngeal bleeding is rare. In most cases such a complication is described after head and neck trauma. Complicating factors include anticoagulant therapy, tumour, aneurysm, infection or major cervical spine injury. A precise initial diagnosis is necessary to avoid a life-threatening situation. Lateral X-ray and computed tomography is essential for safe management. Treatment depends upon size of the haematoma as well as the clinical course of the patient. Smaller haematomas may be observed. Lager haematomas and those that fail to reabsorb should undergo drainage.   相似文献   
104.
105.
Acute myelogenous leukemia (AMU is a hematologic disorder that is characterized by an abnormal proliferation of immature myeloid cells. Granulocytic sarcomas are clusters of leukemic myeloid cells that may develop as a result of AML. Oral manifestations of AML are common and often involve enlargements of the gingiva and/or mucosal tissue from direct leukemia cell infiltration. We describe the case history of a 50-year-old man who had an ulcera-tive lesion of the oral mucosa that was determined to be a granulocytic sarcoma of AML-M0 subtype. The combination of both the subtype and clinical presentation of the leukemia makes this presentation unusual, and to the best of our knowledge, of a type that has not been previously reported in the literature.  相似文献   
106.
Phase II clinical trials are performed to investigate whether a novel treatment shows sufficient promise of efficacy to justify its evaluation in a subsequent definitive phase III trial, and they are often also used to select the dose to take forward. In this paper we discuss different design proposals for a phase II trial in which three active treatment doses and a placebo control are to be compared in terms of a single‐ordered categorical endpoint. The sample size requirements for one‐stage and two‐stage designs are derived, based on an approach similar to that of Dunnett. Detailed computations are prepared for an illustrative example concerning a study in stroke. Allowance for early stopping for futility is made. Simulations are used to verify that the specified type I error and power requirements are valid, despite certain approximations used in the derivation of sample size. The advantages and disadvantages of the different designs are discussed, and the scope for extending the approach to different forms of endpoint is considered. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
107.
Against the theoretical background of the effort–recovery model and the action regulation theory, the author presents a cross‐sectional questionnaire study testing hypotheses about the relationship between work‐related time pressure, cognitive and emotional irritation, work–family conflict and psychosomatic complaints. Subjects were 576 female home care nurses. Results of a path analysis show that the relation of time pressure and psychosomatic complaints is partially mediated by experiencing a work–family conflict; also the relation of time pressure and work–family conflict is partially mediated by cognitive and emotional irritation. It is argued that cognitive and emotional irritation are fruitful concepts for a more comprehensive understanding of the relationship between work stressors and the development of strain‐based work–family conflict. Implications for the prevention of work–family conflict are outlined. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
108.
109.
The Mac-1 integrin is an important mediator of migration and inflammatory activation of neutrophils and monocytes. However, the role of Mac-1 in modulating macrophage emigration and activation and its subsequent impact on cutaneous wound healing have not been fully elucidated. To examine the significance of Mac-1 to murine wound healing, we measured epithelialization and granulation tissue formation in partial-thickness ear wounds and full-thickness head wounds, respectively, in Mac-1-deficient mice. Wounds were histologically analyzed at postwounding days 3, 5, and 7. The gap measured between the leading edges of inward-migrating granulation tissue was significantly increased in knockout mice compared with control animals at day 5 (3.8+/-0.3 vs. 2.6+/-0.5 mm; p<0.001) and day 7 (2.2+/-0.4 vs. 0.96+/-0.73 mm; p=0.005). Epithelial gap measurements were also increased in knockout mice vs. wild-type controls at days 3 (0.62+/-0.02 vs. 0.54+/-0.07 mm; p<0.05) and 5 (0.58+/-0.06 vs. 0.39+/-0.08 mm; p<0.001). Immunohistochemistry showed equal numbers of macrophages in knockout and control wounds. These findings show that Mac-1 is required for normal wound healing but that the attenuation in the deposition of granulation tissue and wound epithelialization in Mac-1 knockout mice is not associated with decreased monocyte migration into the wound.  相似文献   
110.
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