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   1909篇
  免费   148篇
  国内免费   17篇
耳鼻咽喉   7篇
儿科学   42篇
妇产科学   36篇
基础医学   170篇
口腔科学   9篇
临床医学   256篇
内科学   385篇
皮肤病学   21篇
神经病学   85篇
特种医学   53篇
外科学   188篇
综合类   31篇
预防医学   95篇
眼科学   125篇
药学   368篇
中国医学   15篇
肿瘤学   188篇
  2022年   13篇
  2021年   32篇
  2020年   17篇
  2019年   27篇
  2018年   33篇
  2017年   45篇
  2016年   32篇
  2015年   63篇
  2014年   65篇
  2013年   77篇
  2012年   119篇
  2011年   131篇
  2010年   84篇
  2009年   66篇
  2008年   120篇
  2007年   113篇
  2006年   107篇
  2005年   108篇
  2004年   79篇
  2003年   97篇
  2002年   83篇
  2001年   70篇
  2000年   66篇
  1999年   60篇
  1998年   27篇
  1997年   15篇
  1996年   13篇
  1995年   14篇
  1994年   11篇
  1993年   11篇
  1992年   29篇
  1991年   15篇
  1990年   12篇
  1989年   19篇
  1988年   12篇
  1987年   16篇
  1986年   18篇
  1985年   19篇
  1984年   9篇
  1983年   11篇
  1981年   7篇
  1979年   19篇
  1978年   14篇
  1976年   13篇
  1975年   9篇
  1974年   15篇
  1973年   8篇
  1971年   7篇
  1970年   5篇
  1969年   5篇
排序方式: 共有2074条查询结果,搜索用时 250 毫秒
91.

Background

Microsatellite instability (MSI) is one of the leading mechanisms for the carcinogenesis of gastric cancer. Its prognostic value is controversial.

Methods

Between May 1988 and Oct 2003, a total of 214 gastric cancer patients undergoing curative surgery were enrolled, and their MSI statuses were classified as MSI-H (high) or MSI-L/S (low/stable). The clinicopathologic characteristics of MSI-H and MSI-L/S gastric cancers were compared.

Results

The MSI-H tumors accounted for 11.7?% (n?=?25) of the 214 total gastric cancers. Although not statistically significant, the MSI-H gastric cancers were more frequently located in the lower third of the stomach (64?% vs. 49.2?%) and were more often the intestinal type (72?% vs. 61.4?%) compared to the MSI-L/S gastric cancers. The MSI-H gastric cancers had a significantly better 5-year overall survival (OS) rate (68?% vs. 47.6?%, p?=?0.030) and a trend of a better 3-year disease-free survival rate (71.8?% vs. 55.2?%, p?=?0.076) compared to the MSI-L/S gastric cancers. A multivariate analysis revealed that pathologic TNM stage and MSI status were the independent prognostic factors for OS after curative surgery.

Conclusions

Compared to MSI-L/S tumors, MSI-H tumors are associated with a better OS rate for gastric cancer patients after R0 resection.  相似文献   
92.

Purpose  

Patient reporting of type 2 diabetes symptoms in a questionnaire with a 7-day recall period was expected to be different from symptom reports using a 7-day diary with repeated 24-h recall based on cognitive theory of memory processes and prior literature. This study compared these two types of recall in patients diagnosed with type 2 diabetes (T2D).  相似文献   
93.
Background. Nephropathy associated with contrast medium exposure is a well-known complication of IVP. However, it is uncertain whether iso-osmolar non-iodinated contrast medium (iodixanol) is less nephrotoxic than low-osmolar contrast medium (iohexol). Materials and Methods. In this single-center, double-blind, prospective study, 50 patients undergoing IVP were randomized into two groups receiving different contrast medium: iodixanol and iohexol. Patients in high risk for contrast nephropathy were included, 28 with renal insufficiency and 19 with diabetes mellitus. We compared the nephrotoxic effect (contrast nephropathy), complement and cytokines profile between the iodixanol and iohexol groups. The mean volume of contrast medium in each IVP procedure was 0.8 mL/kg. Results. The incidence of contrast nephropathy was 4 percent among all patients (one iodixanol and one iohexol). We found no significant differences in contrast nephropathy and allergic reactions between the two groups. There was no significant difference in cytokine profiles in both groups (p > 0.05).The incidence of allergic reaction was 16 percent among all patients. Twelve percent (3/25) had late reaction after iohexol exposure compared to four percent (2/25) with iodixanol (p = 1.0). One patient had severe skin rash due to late adverse reaction after iodixanol. No mortality was found. Conclusions. New iodixanol and iohexol contrast medium for routine IVP examination are safe and have low nephrotoxicity profile, especially in elderly or high-risk patients. Iodixanol contrast medium has an increased risk to induce severe late adverse reaction compared to iohexol. Allergic reaction may be the main adverse effect after contrast medium infusion.  相似文献   
94.
95.
96.
97.
98.
To investigate the role of plasma calcitonin gene-related peptide (CGRP) in paediatric migraine, we prospectively collected 134 blood samples during or between attacks from 66 migraine, 33 non-migraine headache (non-migraine) and 22 non-headache patients, aged 4–18 years. Plasma CGRP concentrations were measured by enzyme-linked immunosorbent assay and disability by Pediatric MIgraine Disability ASsessment (PedMIDAS) questionnaire. Migraineurs had higher plasma CGRP levels than non-migraine patients ( P  = 0.007). The attack level was higher than the non-attack level in migraine ( P  = 0.036), but not in non-migraine, patients. This was also revealed in paired comparison ( n  = 9, P  = 0.015 vs. n  = 4, P  = 0.47). Using a threshold of 55.1 pg/ml, the sensitivity of the attack level in predicting migraine was 0.81, and specificity 0.75. The PedMIDAS score tended to be higher in the high CGRP (> 200 pg/ml, n  = 7) group than in the low (< 200 pg/ml, n  = 33) group (26.07 vs. 19.32, P  = 0.16) using Mann–Whitney test. Plasma CGRP is useful for diagnosis in paediatric migraine.  相似文献   
99.
目的:探讨在缺氧性损害下肼屈嗪对视网膜色素上皮(ARPE-19)细胞的抗氧化效果以及活性氧(ROS)在此效果中的作用。方法:用人视网膜色素上皮细胞研究肼屈嗪对氧化应激的作用,包括特丁基氢过氧化物(t-BHP)、过氧化氢(H2O2)、叠氮化钠(NaN3),以及缺氧引起的细胞坏死。用MTT检验测试细胞活性。结果:用ROS诱导的氧化应激治疗ARPE-19细胞,肼屈嗪在抵抗t-BHP、H2O2、缺氧引起的细胞坏死中表现出浓度依赖性,但对NaN3不具有浓度依赖性。这一作用中不涉及到一氧化氮(NO)。结论:肼屈嗪在ARPE-19细胞中表现出抗氧化应激诱导的破坏,这一作用可能是因为对ROS的净化剂作用。所以肼屈嗪可能用于治疗老年黄斑变性。  相似文献   
100.
Rogers JV  Hull BE  Fink PS  Chiou HC  Bigley NJ 《Vaccine》2000,18(15):1522-1530
Plasmid DNA encoding herpes simplex virus type-1 glycoprotein D (gD-1) was complexed with asialoorosomucoid conjugated to poly-L-lysine. Following its intravenous injection into BALB/c mice, this complex was targeted to the liver. Liver cells expressing gD-1 were detected immunohistochemically through day 6 post-immunization, while gD-1 DNA was detectable through 14 days post-immunization. Decline of gD-1 expression and detectable gD-1 DNA in the liver correlated with influx of T cells, predominantly CD4(+). The ASOR-poly-L-lysine DNA carrier system promotes hepatic expression of gD-1 and may be useful in vaccination against herpes simplex virus type-1.  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