全文获取类型
收费全文 | 24039篇 |
免费 | 1526篇 |
国内免费 | 668篇 |
专业分类
耳鼻咽喉 | 157篇 |
儿科学 | 492篇 |
妇产科学 | 354篇 |
基础医学 | 2272篇 |
口腔科学 | 427篇 |
临床医学 | 2952篇 |
内科学 | 2999篇 |
皮肤病学 | 410篇 |
神经病学 | 1156篇 |
特种医学 | 1311篇 |
外科学 | 2568篇 |
综合类 | 3611篇 |
预防医学 | 2937篇 |
眼科学 | 269篇 |
药学 | 2561篇 |
21篇 | |
中国医学 | 1115篇 |
肿瘤学 | 621篇 |
出版年
2024年 | 36篇 |
2023年 | 281篇 |
2022年 | 657篇 |
2021年 | 1052篇 |
2020年 | 832篇 |
2019年 | 744篇 |
2018年 | 732篇 |
2017年 | 754篇 |
2016年 | 756篇 |
2015年 | 806篇 |
2014年 | 1632篇 |
2013年 | 1737篇 |
2012年 | 1362篇 |
2011年 | 1616篇 |
2010年 | 1271篇 |
2009年 | 1114篇 |
2008年 | 1168篇 |
2007年 | 1095篇 |
2006年 | 941篇 |
2005年 | 891篇 |
2004年 | 748篇 |
2003年 | 688篇 |
2002年 | 601篇 |
2001年 | 493篇 |
2000年 | 406篇 |
1999年 | 346篇 |
1998年 | 348篇 |
1997年 | 324篇 |
1996年 | 297篇 |
1995年 | 280篇 |
1994年 | 194篇 |
1993年 | 193篇 |
1992年 | 171篇 |
1991年 | 169篇 |
1990年 | 141篇 |
1989年 | 134篇 |
1988年 | 118篇 |
1987年 | 120篇 |
1986年 | 101篇 |
1985年 | 136篇 |
1984年 | 144篇 |
1983年 | 83篇 |
1982年 | 113篇 |
1981年 | 73篇 |
1980年 | 56篇 |
1979年 | 74篇 |
1978年 | 42篇 |
1977年 | 46篇 |
1976年 | 52篇 |
1975年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
Nixie G. Raymond Johanna T. Dwyer Patricia Nevins Paul Kurtin 《Pediatric nephrology (Berlin, Germany)》1990,4(2):145-151
Children with mild to moderate renal insufficiency may be at an increased risk for developing glomerulosclerosis and subsequent renal failure. Low protein diets (LPD) have been shown to delay the progression of renal insufficiency in laboratory animals and may be of benefit in adult humans. The nutritional costs of a LPD in adults are reportedly minimal. We review the protein and caloric requirements of growing children and discuss the potential harmful effects and benefits of an LPD in this population. We also discuss dietary adherence and the difficulty of designing an LPD for children. We conclude that the protein content of a typical American diet can safely be reduced to, but not below, the recommended daily allowance for protein if diets are carefully planned, patients and their parents extensively counseled, and if dietary supplements are given to help meet the caloric and vitamin-mineral nutrient needs of growing children. In addition, ongoing nutritional assessment, counseling, and frequent monitoring of growth, diet and biochemical indicators of protein status are essential for maintaining the health of these children. 相似文献
142.
目的:研究钛接圈在不同烘烤温度下浇注镍铬合金的质量关系。方法:选择临床骨融合种植义齿二期手术后典型病例石膏模型,在基桩上固定纯钛接圈,常规制作桥架蜡型,使桥架接圈周围嵌体蜡厚度为1mm,常规内、外包埋,放置24h后,分4组不同温度烘烤,a组烘烤升温至600℃,b组升温至650℃,c组升温至700℃,d组升温至800℃。每组试件10个,共40个试件。用远红外温度测试仪控制合金浇注温度为1306℃,自然冷却后,电镜观察。结果:钛接圈烘烤温度600℃、800℃时镍铬合金支架断口出现二次断裂及气孔机会多,当650℃、700℃时二次断裂出现机会少。结论:在常规牙科操作中,钛接圈烘烤温度为650℃、700℃时,浇注镍铬合金较好。 相似文献
143.
E. Guerrero-Lindner M. Castro J. M. MuÑoz M. P. Arruebo M.D. Murillo L. Buéno† & M.A. plaza 《Neurogastroenterology and motility》2003,15(3):307-316
Cytokines are involved in fever and other symptoms of the acute phase response induced by endotoxins. The aim of this work was to study the involvement of central tumour necrosis factor-alpha (TNF-alpha) in the changes induced by lipopolysaccharide (LPS) on gastrointestinal (GI) motility in sheep. Body temperature and myoelectric activity of the antrum, duodenum and jejunum was recorded continuously. Intravenous (i.v.) administration of LPS (0.1 micro g kg-1)-induced hyperthermia, decreased gastrointestinal myoelectric activity and increased the frequency of the migrating motor complex (MMC). These effects started 40-50 min after LPS and lasted for 6-7 h. TNF-alpha (50 and 100 ng kg-1) mimicked these effects when injected intracerebroventricularly (i.c.v.) but not i.v. Pretreatment with soluble recombinant TNF receptor (TNFR:Fc, 10 micro g kg-1, i.c.v.) abolished the TNF-induced actions and reduced those evoked by LPS. Furthermore, the effects induced by either LPS or TNF were suppressed by prior i.c.v. injection of indomethacin (100 micro g kg-1). In contrast, the i.v. injections of TNFR:Fc or indomethacin were ineffective. Our data suggest that LPS disturbs GI motility in sheep through a central pathway that involves TNF-alpha and prostaglandins sequentially. 相似文献
144.
A. G. BIRKS H. IZZARD D. R. MORROLL J. R. PRIOR S. A. TROUP B. A. LIEBERMAN I. L. MATSON 《International journal of andrology》1994,17(6):289-291
The World Health Organization (WHO) laboratory manual (1992) states that assessment of sperm motility can be performed at either 37O C or room temperature (20–24O C). The motility of spermatozoa in 44 semen samples (22 fresh samples and 22 frozen-thawed samples) was assessed at both of these temperatures and a significant difference in the motility profiles was noted, specifically an increase at 37O C in the percentage (expressed here as median and ranges) of spermatozoa with excellent progressive motility and an overall increase in the percentage with total progressive motility. With fresh samples the excellent progressive motility increased from 41 (19–53) to 54 (30–66) and the overall motility from 58.5 (39–74) to 65.0 (40–79). With the frozen—thawed samples the excellent motility increased from 14 (1–33) to 25 (6–45) and the overall motility from 30.5 (14–51) to 33.0 (16–52). As the WHO laboratory manual was published. 'In response to a growing need for the standardisation of procedures for the examination of human spermatozoa' it is proposed that only one temperature for routine analysis should be used, namely 37O C, which may have more physiological relevance and eliminate effects of fluctuations in ambient laboratory temperature. 相似文献
145.
146.
M. S. Avidan N. Jones R. Ing M. Khoosal C. Lundgren & D. F. Morrell 《Anaesthesia》1997,52(11):1073-1076
We sought to determine whether the forced air convection warmers (nine Bair Huggers, Augustine Medical, and one Warm Touch, Mallinkrodt Medical) used in our operating theatres could be a source of microbial pathogens. Agar plates were placed directly in the air stream of the warmers. Four of these grew potentially pathogenic organisms. When the warmers were set to blow through perforated blankets, no growth occurred. Three of the warmers were swabbed and sites of colonisation were found in their hoses. After fixing a microbial filter to the end of the hose, organisms were no longer detectable. We conclude that these warming devices are a potential source of nosocomial infection. They should only be used in conjunction with perforated blankets, should have their microbial filters changed regularly and their hoses sterilised. The inclusion of a microbial filter into the nozzle of the hose could be incorporated into the design of the warmer. 相似文献
147.
S. A. Carter 《Clinical physiology and functional imaging》1991,11(3):253-261
Summary. The effect of changes in local and body temperature on the toe systolic pressures was studied in 20 subjects with and 30 without Raynaud's syndrome in the toes. The pressures were significantly lower in the group with Raynaud's syndrome under all experimental conditions (P < 0·01). The pressures were significantly lower during body cooling than during body warming in both groups (P < 0·01). The mean decrease with body cooling was 58 mmHg in the group with Raynaud's syndrome and 24 mmHg in the control subjects (P < 0·01). During body cooling pressures fell to less than 30 mmHg in 70% of subjects with Raynaud's syndrome and in 3% of the controls. Local cooling from 30 to 10°C during body cooling resulted in a significant mean decrease in pressure of over 40 mmHg in both groups (P < 0·01) and the pressure fell below 30 mmHg in over 90% of the group with and in 26% of those without Raynaud's attacks. The results indicate the importance of body cooling and local temperature in the mechanism of vasospasm in the toes. They are also relevant to the diagnosis of Raynaud's syndrome in the lower limbs and have implications for the testing of patients with arteriosclerotic occlusion since erroneously low pressure values could be obtained in tests when the feet are cold. 相似文献
148.
Myocardial protection in adult cardiac surgery: current options and future challenges 总被引:3,自引:0,他引:3
Francesco Nicolini Cesare Beghi Claudio Muscari Andrea Agostinelli Alessandro Maria Budillon Igino Spaggiari Tiziano Gherli 《European journal of cardio-thoracic surgery》2003,24(6):986-993
Current techniques of myocardial protection are evolving with the use of less conventional modalities of cardioplegia and have reduced the morbidity and mortality of cardiac operations. Blood cardioplegic solutions appear superior to cold cardioplegia in terms of myocardial protection and adjuncts as glutamate/aspartate enhancement, antioxidant supplementation, nitric oxide donors and maintenance of calcium homeostasis seem effective. In the near future, further experimental and clinical investigations about pharmacological preconditioning, sodium–hydrogen exchangers inhibition and gene therapy need to be addressed to well define their potential role in the improvement of current techniques of myocardial protection that are suboptimal in high-risk clinical settings. 相似文献
149.
V. Gh. MUSTEATA I. T. CORCIMARU I. A. IACOVLEVA L. Z. MUSTEATA I. S. SUHARSCHII L. T. ANTOCI 《International journal of laboratory hematology》2004,26(6):397-401
The purpose of this comparative study was to evaluate the response of primary splenic low‐grade non‐Hodgkin's lymphomas (NHL) to chemotherapy, splenectomy, and chemotherapy combined with splenectomy in order to elaborate the optimum treatment modality. A total of 104 patients (age range: 15–82 years) with primary low‐grade B‐cell NHL of the spleen were comprised by our study. Stage IV disease was determined in 102 (98.1%) cases. Regarding the treatment modality, splenectomy was performed in 14 patients, early splenectomy and single‐agent chemotherapy in 15, early splenectomy and combined chemotherapy in 19, single‐agent chemotherapy in 23, and combined chemotherapy in 33. In the above‐mentioned order, complete remission rate was following: none, 40.0, 31.6, 21.8, and 18.2%. Partial remissions were achieved in 85.7, 46.7, 57.9, 30.4, and 69.7% of cases, respectively. The median remission duration turned out to be longer (74.5 months) in the group of patients with complete remissions attained by means of splenectomy and combined chemotherapy. Local relapses in the spleen developed in 19 (72.7%) patients treated with combined chemotherapy and in 9 (90.0%), who had undergone single‐agent chemotherapy. The 5‐year overall survival was 54.4% after splenectomy, 39.4% after single‐agent chemotherapy, and 37.1% after combined chemotherapy, being significantly higher (P < 0.05) after splenectomy and single‐agent chemotherapy (67.2%), and splenectomy followed by combined chemotherapy (64.7%). Early splenectomy combined with chemotherapy is the optimum treatment option for primary low‐grade NHL of the spleen because of the superiority in complete remission rate, remission duration, and in overall survival rate. Splenectomy leads to somatic compensation of patients, makes impossible local relapsing in the spleen, prevents continuous dissemination from the primary tumor site, and mostly corrects cytopenias, creating better conditions for chemotherapy. 相似文献
150.
为研究温血停搏液(谷氨酸加天门冬氨酸强化)诱导停跳和主动脉开放前再灌注的未成熟心肌保护的效果。用12只新西兰幼免(3~4周),体重450~550g,随机分成2组:冷血停搏液(谷氨酸加天门冬氨酸强化)组(Ⅰ组,n=6);温血停搏浪诱导及再灌注血组(Ⅱ组,n=6)。结果:1.心功能;CO±dp0/dt恢复百分率Ⅱ组明显优于Ⅰ组(P<0.01);LVSP恢复百分率Ⅱ组优于Ⅰ组(P<0.05)。2.LDH和CK漏出量(U/l)Ⅱ组明显优于Ⅰ组(P<0.01);3。心肌含水量(%)Ⅱ组优于Ⅰ组(P<0.01);4.心肌结构保护Ⅱ组明显优于Ⅰ组。本实验提示:温血诱导停跳与主动脉开放前温血再灌注对于未成熟心肌有良好的心肌保护效果。 相似文献