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   63446篇
  免费   9929篇
  国内免费   123篇
耳鼻咽喉   694篇
儿科学   1644篇
妇产科学   2848篇
基础医学   7124篇
口腔科学   1175篇
临床医学   21146篇
内科学   10397篇
皮肤病学   649篇
神经病学   4214篇
特种医学   1641篇
外国民族医学   1篇
外科学   6997篇
综合类   942篇
一般理论   29篇
预防医学   6296篇
眼科学   693篇
药学   3684篇
中国医学   62篇
肿瘤学   3262篇
  2023年   933篇
  2022年   372篇
  2021年   832篇
  2020年   1006篇
  2019年   891篇
  2018年   1856篇
  2017年   1887篇
  2016年   2093篇
  2015年   2198篇
  2014年   2514篇
  2013年   3280篇
  2012年   2506篇
  2011年   2817篇
  2010年   2234篇
  2009年   2392篇
  2008年   2511篇
  2007年   2490篇
  2006年   2464篇
  2005年   2317篇
  2004年   2198篇
  2003年   2094篇
  2002年   2071篇
  2001年   2019篇
  2000年   1855篇
  1999年   1787篇
  1998年   1179篇
  1997年   1186篇
  1996年   1059篇
  1995年   1024篇
  1994年   838篇
  1993年   730篇
  1992年   1363篇
  1991年   1284篇
  1990年   1262篇
  1989年   1128篇
  1988年   1009篇
  1987年   1029篇
  1986年   985篇
  1985年   1025篇
  1984年   806篇
  1983年   698篇
  1982年   508篇
  1981年   436篇
  1980年   411篇
  1979年   653篇
  1978年   497篇
  1977年   425篇
  1976年   433篇
  1974年   410篇
  1972年   419篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
A novel injectable scaffolding matrix (E-Matrix) has been developed to accelerate wound healing in diabetic foot ulcers. This porcine collagen-derived matrix is designed to mimic tertiary embryonic connective tissue and to stimulate fetal wound repair mechanisms including angiogenesis. In vitro and animal studies have indicated a beneficial effect on tissue growth and an acceptable safety profile. In this report, we describe the initial use of this product in a pilot study of six humans with chronic nonhealing diabetic foot ulcers. A dramatic initial response to injection was seen, with an average wound size reduction of 72% 2 weeks after injection. Randomized trials are underway to define the potential benefit of this new treatment modality for diabetic foot ulcers.  相似文献   
142.
143.
PROBLEM: To compare depressive symptoms in children with attention deficit hyperactivity disorder (ADHD) to those in healthy children, and to explore the influence of individual and family factors on level of depression. METHODS: Individual interviews with 68 children, ages 7 to 12 years, in order to complete the Children's Depression Inventory. FINDINGS: Children with ADHD reported significantly more depressive symptoms than did children without ADHD; 14.7% of children with ADHD reached the threshold of a 19 point score, which suggests clinical depression. No significant effects of individual and family factors on level of depression were found. CONCLUSIONS: Children with ADHD are more inclined to experience depressive symptoms than are healthy children. To plan appropriate interventions, nurses evaluating and working with children with ADHD should always consider a possible coexistence of depressive symptoms.  相似文献   
144.
145.
Psychiatric morbidity in Hobart's dependent aged   总被引:1,自引:0,他引:1  
Psychiatric morbidity in the dependent aged was studied in the elderly population of Hobart's nursing homes and long-stay hospitals. Only patients with home addresses in Hobart and who were admitted for the first time aged 70 years or over were included. Three hundred and twelve persons were interviewed with a standard interview, and an informant was interviewed when appropriate. The medical records were searched for diagnoses and drug treatments. Physical disability was rated on an ad hoc scale. Comparisons were made of the prevalence of dementia, depression and anxiety in different types of unit, and between these and two domiciliary samples, one of which received domiciliary nursing services (n = 100) and the other not (n = 100). The differential use of institutions by men and women, and a possible sex difference in the prevalence of dementia is discussed.  相似文献   
146.
The inference that mitral valve replacement (MVR) may produce left ventricular outflow tract (LVOT) obstruction has been made, but no comparative hemodynamic studies with various types of prostheses have been done. The purpose of the present study was to compare the gradients created across the LVOT with MVR in young sheep with small left ventricular cavities. Mitral valve replacement was accomplished using cardiopulmonary bypass and hypothermic cardioplegic arrest. Five animals were used for each of the following valves studied: 25-mm Ionescu-Shiley bovine pericardial valve, 25-mm Hancock porcine aortic valve, 2M-6120 28-mm Starr-Edwards ball-valve prosthesis, 25-mm Bj?rk-Shiley 60-degree flat tilting-disc prosthesis, and 25-mm St. Jude Medical hemidisc valve. Gradients across the LVOT were measured after MVR and then during infusion of isoproterenol hydrochloride (0.05 micrograms/kg/min). Following MVR, only the Starr-Edwards valve produced an LVOT gradient (32 +/- 23 mm Hg). Substantial gradients after MVR were seen, however, with isoproterenol administration with the Ionescu-Shiley (47 +/- 4 mm Hg), Hancock (13 +/- 8 mm Hg), and Starr-Edwards (65 +/- 30 mm Hg) valves but not with the low-profile valves (Bj?rk-Shiley and St. Jude Medical). The results of the present study demonstrate that MVR can produce LVOT obstruction. The greatest degree of obstruction was with the high-profile mechanical and bioprosthetic valves.  相似文献   
147.
148.
Akt, a Serine/Threonine protein kinase, mediates growth factor-associated cell survival. Constitutive activation of Akt (phosphorylated Akt, P-Akt) has been observed in several human cancers, including lung cancer and may be associated with poor prognosis and chemotherapy and radiotherapy resistance. The clinical relevance of P-Akt in non-small cell lung cancer (NSCLC) is not well described. In the present study, we examined 82 surgically resected snap-frozen and paraffin-embedded stage I to IIIA NSCLC samples for P-Akt and Akt by Western blotting and for P-Akt by immunohistochemistry. P-Akt protein levels above the median, measured using reproducible semiquantitative band densitometry, correlated with a favorable outcome (P = 0.007). Multivariate analysis identified P-Akt as a significant independent favorable prognostic factor (P = 0.004). Although associated with a favorable prognosis, high P-Akt levels correlated with high tumor grade (P = 0.02). Adenocarcinomas were associated with low P-Akt levels (P = 0.039). Akt was not associated with either outcome or clinicopathologic variables.Cytoplasmic (CP-Akt) and nuclear (NP-Akt) P-Akt tumor cell staining was detected in 96% and 42% of cases, respectively. Both CP-Akt and NP-Akt correlated with well-differentiated tumors (P = 0.008 and 0.017, respectively). NP-Akt also correlated with nodal metastases (P = 0.022) and squamous histology (P = 0.037).These results suggest P-Akt expression is a favorable prognostic factor in NSCLC. Immunolocalization of P-Akt, however, may be relevant as NP-Akt was associated with nodal metastases, a known poor prognostic feature in this disease. P-Akt may be a potential novel therapeutic target for the management of NSCLC.  相似文献   
149.
150.
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