全文获取类型
收费全文 | 17857篇 |
免费 | 1440篇 |
国内免费 | 348篇 |
专业分类
耳鼻咽喉 | 167篇 |
儿科学 | 427篇 |
妇产科学 | 409篇 |
基础医学 | 1228篇 |
口腔科学 | 96篇 |
临床医学 | 2331篇 |
内科学 | 3413篇 |
皮肤病学 | 63篇 |
神经病学 | 1176篇 |
特种医学 | 466篇 |
外科学 | 2016篇 |
综合类 | 1875篇 |
现状与发展 | 1篇 |
预防医学 | 2760篇 |
眼科学 | 47篇 |
药学 | 2560篇 |
10篇 | |
中国医学 | 240篇 |
肿瘤学 | 360篇 |
出版年
2024年 | 41篇 |
2023年 | 359篇 |
2022年 | 564篇 |
2021年 | 849篇 |
2020年 | 777篇 |
2019年 | 679篇 |
2018年 | 663篇 |
2017年 | 640篇 |
2016年 | 663篇 |
2015年 | 639篇 |
2014年 | 1153篇 |
2013年 | 1392篇 |
2012年 | 1074篇 |
2011年 | 1110篇 |
2010年 | 828篇 |
2009年 | 807篇 |
2008年 | 807篇 |
2007年 | 771篇 |
2006年 | 695篇 |
2005年 | 588篇 |
2004年 | 508篇 |
2003年 | 448篇 |
2002年 | 319篇 |
2001年 | 317篇 |
2000年 | 297篇 |
1999年 | 256篇 |
1998年 | 248篇 |
1997年 | 233篇 |
1996年 | 198篇 |
1995年 | 261篇 |
1994年 | 161篇 |
1993年 | 135篇 |
1992年 | 140篇 |
1991年 | 141篇 |
1990年 | 120篇 |
1989年 | 93篇 |
1988年 | 109篇 |
1987年 | 83篇 |
1986年 | 80篇 |
1985年 | 85篇 |
1984年 | 69篇 |
1983年 | 44篇 |
1982年 | 38篇 |
1981年 | 31篇 |
1980年 | 31篇 |
1979年 | 26篇 |
1978年 | 24篇 |
1977年 | 16篇 |
1975年 | 10篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
11.
12.
Factor Xa-activated whole blood clotting time (Xa-ACT) for bedside monitoring of dalteparin anticoagulation during haemodialysis. 总被引:1,自引:1,他引:0
Rolf Dario Frank Vincent M Brandenburg Regina Lanzmich Jürgen Floege 《Nephrology, dialysis, transplantation》2004,19(6):1552-1558
BACKGROUND: Low molecular weight heparins (LMWH) like dalteparin are increasingly used for anticoagulation during haemodialysis (HD). The available laboratory tests for monitoring LMWH anticoagulation are time-consuming and expensive, and the suitability of the conventional activated clotting time (ACT) is controversial. A simple and cheap bedside test would be useful. METHODS: We studied the factor Xa-activated whole blood clotting time (Xa-ACT) in vitro and in vivo in nine patients undergoing chronic HD with i.v. dalteparin bolus anticoagulation and compared it with the conventional ACT. Plasma anti-factor Xa (antiXa) activity was determined with a chromogenic assay. Thrombin-antithrombin complexes were measured to detect coagulation activation. RESULTS: Xa-ACT and ACT were prolonged with rising dalteparin concentration. In vitro, both clotting times were strongly correlated with the antiXa levels (r = 0.94 and 0.89, respectively). Nevertheless, compared with the ACT, the Xa-ACT was considerably more sensitive to the LMWH in vitro (healthy blood: Xa-ACT 90 s/U vs ACT 26 s/U; uraemic blood: Xa-ACT 96 s/U vs ACT 31 s/U) as well as in vivo (Xa-ACT 81 s/U vs ACT 22 s/U) and reflected different intensities of anticoagulation. An initial dalteparin bolus of 80+/-11 U/kg body weight was able to prevent coagulation activation for up to 4 h of HD. CONCLUSION: For monitoring LMWH anticoagulation the Xa-ACT was superior to the conventional ACT in vitro as well as in vivo during HD. The Xa-ACT can be useful as a LMWH bedside test. The ACT was not sensitive enough to serve as a LMWH monitoring tool. 相似文献
13.
介绍了蓬辣滩水电站泄洪闸门的状况、计算机监控系统改造方案的结构和特点及闸门定轮轴承的改造情况,通过上述改造,提高了泄洪设备运行的自动化水平,同时也为其他闸门工程提供参考。 相似文献
14.
特异性荧光偏振免疫法监测521例肾移植后环孢素A全血浓度3275次 总被引:2,自引:0,他引:2
目的通过监测肾移植后病人环孢素A(CsA)全血浓度 ,提出CsA在三联免疫抑制用药方案中的理想治疗窗。方法用特异性荧光偏振免疫法测定CsA全血浓度 ,对521例病人监测3275次 ,按术后时间及临床表现分组比较。结果肾移植后<1 ,、1~3、3~6、6~12个月、1~2和>2年的CsA全血谷浓度的理想治疗窗应分别为250~450、200~400、150~300、100~250、100~200和100~180μg/L。结论CsA全血浓度在上述范围内 ,中毒反应和排异反应明显减少 相似文献
15.
B. Hagander J. Holm† N.-G. Asp† S. Efendi‡ I. Lundquist§ P. Nilsson-Ehle B. Scherstén 《Journal of human nutrition and dietetics》1988,1(4):239-246
Test meals with 10.9 g dietary fibre from sugar beet and corresponding control meals were given to eight healthy subjects, aged 67 ± 9 years. The postprandial glucose, triglyceride, hormone and glycerol responses were monitored during 3 hours. After the beet fibre meal the insulin and C-peptide areas were reduced by 28 ( P < 0.01) and 22% ( P > 0.025), respectively, and the somatostatin levels increased by approximately 30% ( P > 0.05). Further, the maximum relative postprandial reduction of plasma glycerol levels was less evident after the fibre-rich meal than after the control meal (36 ± 4% v. 46 ± 4%, P < 0.05). There was no apparent difference in the overall glycaemic response between the meals. The triglyceride levels were similar after both test meals.
Suspension of beet fibre bread given to rats by oro-gastric intubation induced lower blood glucose response than a control bread at 15 and 30 min ( P < 0.001), respectively, but a similar insulin response.
The results suggest an effect of beet fibre on the rate of carbohydrate absorption, expressed as a lower insulin response in the healthy volunteers and a reduced glucose response in the rat.
The mechanism behind this effect in healthy subjects could possibly be mediated by an increased somatostatin response. 相似文献
Suspension of beet fibre bread given to rats by oro-gastric intubation induced lower blood glucose response than a control bread at 15 and 30 min ( P < 0.001), respectively, but a similar insulin response.
The results suggest an effect of beet fibre on the rate of carbohydrate absorption, expressed as a lower insulin response in the healthy volunteers and a reduced glucose response in the rat.
The mechanism behind this effect in healthy subjects could possibly be mediated by an increased somatostatin response. 相似文献
16.
汕头卫生检疫局空港处对汕头航空口岸—宗入境二级货包的监测过程及对有关运输工作人员作了放射知识问卷调查。从中发现。运输单位货物存放设施落后。有关工作人员放射卫生知识欠缺,对放射污染可能造成的危害缺乏正确的认识。为此,笔者提出了自己的看法,以期对放射监测工作的进一步完善提供参考。 相似文献
17.
The application of Doppler-tipped guide wires to measure blood flow velocity in coronary and peripheral arteries has been
described previously as a valuable means of functional assessment in interventional cardiological procedures. In animal studies
intravascular Doppler has been used in the cerebrovascular system, and this appears to be an important field of application
for this new technique. We used intravascular haemodynamic monitoring by the Doppler guide wire during neuroendovascular procedures
in patients with different cerebrovascular diseases and evaluated the clinical feasibility of the method. We found it a safe
technique which complements morphological angiographic information with valuable functional data. Further studies may be expected
to demonstrate the relation of flow parameters to clinical outcome.
Received: 16 January 1996 Accepted: 30 January 1996 相似文献
18.
19.
R. J. Rona A. V. Swan R. Beech D. M. Wilson F. B. Kavanagh C. Brown C. Axtell S. Mandalia 《Clinical genetics》1992,42(4):186-195
For certain genetic conditions DNA testing identifies carriers and determines the risk status of foetuses, thus helping parents to make more informed prenatal decisions. Data, collected from three genetic centres in England and Wales from August 1986 to July 1990, are used to describe trends in demand for DNA testing, the impact of DNA tests on carrier risk assessment, and the use of DNA tests in relation to pregnancy outcome. Altogether the data include 23,388 subjects and 681 pregnancies in 8738 families divided into five cohorts by year of entry and referral. The most frequent gene disorders referred to the genetic centres are currently being tested or will soon be tested. For these disorders the initial high level of activity has declined and may have reached steady state. Demand for DNA services is high for cystic fibrosis and Duchenne muscular dystrophy, intermediate for Huntington's disease, and low for adult polycystic kidney disease, phenylketonuria and tuberous sclerosis. Based on these findings we suggest that demand for DNA tests will be high in serious, untreatable and slow progressing conditions with early onset; intermediate for conditions affecting intellect and neurological integrity with later onset; and low for treatable, late-onset conditions, or those for which there is evidence of heterogeneity, and variable penetrance. It would be helpful to assess the extent to which this view of demand is confirmed when the new disorders being DNA tested are considered and for the pattern of activity of DNA testing for some types of cancer. Since no DNA centre could offer a fully comprehensive testing service, it is recommended that a structure is created to audit overall activity, assist in policy formulation, and influence supraregional service organisation, in order that the spread of DNA services be planned as effectively as possible. This structure would facilitate monitoring of the evolution of contract specifications agreed by commissioners and providers on a regional basis. 相似文献
20.
Effects of smoking and drinking on excretion of hippuric acid among toluene-exposed workers 总被引:1,自引:1,他引:0
Osamu Inoue Kazunori Seiji Takao Watanabe Haruo Nakatsuka Chui Jin Shi-Jie Liu Masayuki Ikeda 《International archives of occupational and environmental health》1993,64(6):425-430
Summary In order to investigate possible effects of smoking and drinking on the metabolism of toluence in occupational settings, 206 toluene-exposed men (mean age: 31.4 years) in shoemaking, painting, or surface-coating workshops together with 246 nonexposed control men (36.8 years) were studied for the time-weighted average intensities of exposure to toluene, hippuric acid concentration in shift-end urine samples, and the two social habits of smoking and drinking. The mean daily consumptions of cigarettes and ethanol were about 20 pieces and 10 g among smokers and drinkers, respectively. The geometric mean toluene concentration among the exposed subjects was about 20 ppm, with a maximum of 521 ppm. Regression analysis after classification of the subjects by smoking and drinking clearly demonstrated that the two social habits, when combined, markedly reduce the hippuric acid level in the urine of workers exposed to was a significant association between smoking and drinking habits, which hindered separate evaluation of the effects of the two habits on toluene metabolism. Comparison of the present results with the findings reported in the literature, however, suggested that the observed effects may be attributable to smoking rather than to drinking habits. 相似文献