全文获取类型
收费全文 | 405791篇 |
免费 | 25755篇 |
国内免费 | 10440篇 |
专业分类
耳鼻咽喉 | 3685篇 |
儿科学 | 12137篇 |
妇产科学 | 4828篇 |
基础医学 | 32480篇 |
口腔科学 | 8882篇 |
临床医学 | 44967篇 |
内科学 | 67682篇 |
皮肤病学 | 6345篇 |
神经病学 | 20095篇 |
特种医学 | 15826篇 |
外国民族医学 | 32篇 |
外科学 | 53805篇 |
综合类 | 39824篇 |
现状与发展 | 41篇 |
一般理论 | 9篇 |
预防医学 | 33338篇 |
眼科学 | 7270篇 |
药学 | 61032篇 |
178篇 | |
中国医学 | 10963篇 |
肿瘤学 | 18567篇 |
出版年
2023年 | 4366篇 |
2022年 | 9796篇 |
2021年 | 16842篇 |
2020年 | 11415篇 |
2019年 | 18824篇 |
2018年 | 14554篇 |
2017年 | 12615篇 |
2016年 | 12588篇 |
2015年 | 15500篇 |
2014年 | 27449篇 |
2013年 | 28752篇 |
2012年 | 28189篇 |
2011年 | 25528篇 |
2010年 | 22252篇 |
2009年 | 20931篇 |
2008年 | 19358篇 |
2007年 | 19414篇 |
2006年 | 16903篇 |
2005年 | 12424篇 |
2004年 | 8136篇 |
2003年 | 7186篇 |
2002年 | 5603篇 |
2001年 | 5009篇 |
2000年 | 4157篇 |
1999年 | 3319篇 |
1998年 | 3373篇 |
1997年 | 3078篇 |
1996年 | 2563篇 |
1995年 | 2526篇 |
1994年 | 2327篇 |
1993年 | 1917篇 |
1992年 | 2159篇 |
1991年 | 1883篇 |
1990年 | 1729篇 |
1989年 | 1662篇 |
1988年 | 1515篇 |
1987年 | 1372篇 |
1985年 | 4598篇 |
1984年 | 5112篇 |
1983年 | 4029篇 |
1982年 | 4607篇 |
1981年 | 4247篇 |
1980年 | 3577篇 |
1979年 | 3392篇 |
1978年 | 2783篇 |
1977年 | 2239篇 |
1976年 | 2617篇 |
1975年 | 1901篇 |
1974年 | 1720篇 |
1973年 | 1644篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
目的:分析用血浆巨细胞病毒(cytomegalovirus,CMV)多聚酶链反应(plymerase chain reaction,PCR)检测结果指导抗CMV干预性治疗的临床意义。方法:1999年8月至2001年7月行异基因造血干细胞移植(hematopoietic stem cell transplantation,HSCT)的所有患者自预处理开始,常规用PCR法检测血浆的CMV-DNA(采用华美公司生产的巨细胞病毒4℃ PCR检测试剂盒),每周1次。其中尚无CMV病的临床表现而检测到血浆CMV阳性的患者89例。随机选取52例阳性患者给予干预性治疗。将上述89例患者分为3组(分别为停止治疗时血浆CMV-PCR转阴组、停止治疗时未转阴组、血浆CMV阳性未治疗组)比较各组CMV病的发生率。CMV病的发生率采用Kaplan-Meier曲线表示,曲线间的比较用Log-Rank(曲线无交叉)或Breslow(曲线交叉)检验,某时点率的比较采用RXC列联表或χ^2检验。结果:100d内CMV病的发生率,在治疗后血浆CMV-PCR由阳性转为阴性组为10.26%,治疗结束时血浆CMV-PCR仍为阳性组为66.67%,血浆CMV-PCR阳性未治疗组为36.24%(P=0.0000)。上述3组中任两组移植后100d CMV病的发生率差异均有显著性。移植后1年时上述3例CMV病累积发生率分别为30.65%、75.00%、42.95%(P=0.0009),治疗未转阴组与治疗转阴组和阳性未治疗组相比,CMV病的发生率明显升高。结论:血浆CMV-PCR检测结果用来指导干预性治疗有一定临床意义。干预性治疗后血浆CMV-DNA仍未转阴者,应考虑换药或联合用药治疗。 相似文献
972.
Mitsuhiko Yanagisawa Rumiko Hosoki Masanori Otsuka 《European journal of pharmacology》1992,220(2-3):111-117
We have developed an isolated spinal cord-skin preparation of the newborn rat. The spinal cord together with a piece of skin connected to the cord by the saphenous nerve was isolated from 1- to 4-day-old rats and separately superfused with artificial cerebrospinal fluid in two neighbouring chambers. Potentials were recorded extracellularly from the third lumbar ventral root. Application of capsaicin (0.5-2 μM) or KCl (60–350 mM) with brief pressure pulses to the perfusion bath of the skin evoked a depolarizing response of 20- to 40-s duration in the ventral root. The response was depressed by [Met5]enkcphalin (0.03–3 μM). morphine (0.1–2 μM) and a tachykinin antagonist, [D-Arg1,D-Trp7,9,Leu11] substance P (spantide), 1–10 μM), applied to the spinal cord by superfusion, whereas the response was augmented by centrally administered calcitonin gene-related peptide (0.1–0.2 μM) or bicuculline (0.5–1 μM). 相似文献
973.
1999~2001年全国治疗药物监测室间质评结果 总被引:1,自引:0,他引:1
目的:通过开展室间质量评价活动提高临床实验室的检验结果质量。方法:每年向参加治疗药物监测(TDM)室间质量评价活动的单位发放质控品10个批号,测定项目包括茶碱、地高辛、苯妥英、苯巴比妥、卡马西平和环孢菌素A,实验室用常规方法测定并回报测定结果,经计算机软件对全部结果进行统计分析。结果:2001年参加TDM室间质评的实验室数为48家,测定结果的平均及格率分别为茶碱94.2%、地高辛82.6%、苯妥英83.8%、苯巴比妥88.4%、卡马西平94.2和环孢菌素A92.4%。1999~2001年全国TDM室间质评的年平均及格率分别为78.7%、84.7%和89.3%。不同测定方法的精密度分别为茶碱4.4%~14.2%、地高辛11.5%~21.9%、苯妥英8.5%~29.5%、苯巴比妥8.2%~13.9%、卡马西平10.8%~12.6%和环孢菌素A15.5%~16.6%。结论:多数参加TDM室间质评实验室的测定结果有较好的一致性,及格率逐年上升,但参加TDM室间质评的实验室数占开展TDM的实验室总数的比例较低,在不同的测定方法间还存在较大的差异。 相似文献
974.
A stratified intraoperative surgical strategy is mandatory during laparoscopic common bile duct exploration for common bile duct stones 总被引:3,自引:0,他引:3
J. F. Gigot B. Navez J. Etienne E. Cambier P. Jadoul P. Guiot P. J. Kestens 《Surgical endoscopy》1997,11(7):722-728
Background: Open exploration and endoscopic sphincterotomy (ES) remain the preferred treatment of common bile duct stones (CBDS). The
recent spread of laparoscopy has worsened the dilemna of choosing between surgical and endoscopic treatment of CBDS. The aim
of this study was to critically evaluate the results of our preliminary experience with laparoscopic common bile duct exploration
(CBDE) for CBDS.
Methods: Ninety-two consecutive patients were prospectively submitted to laparoscopic CBDE. Surgical strategy included an initial
transcystic approach or laparoscopic choledochotomy. Failure of stone clearance was managed by conversion to open CBDE or
by postoperative ES. Electrohydraulic lithotripsy and papillary balloon dilatation were selectively used. Stone clearance
was assessed by choledochoscopy and control cholangiography.
Results: The overall laparoscopic stone clearance in this series was 84% (transcystic route 63% and choledochotomy 93%). Conversion
to laparotomy was mandatory in 12% of the patients because of incomplete stone clearance and in 5% because of intraoperative
complications. Postoperative ES was required in 4% of the patients, giving an overall surgical success rate of 96%. When indicated
(small and limited number of stones located below the cysticocholedochal junction, with a dilated and patent cystic duct)
the transcystic route had the lower success rate, the higher complication rate, and the shorter operative time and postoperative
hospital stay. When indicated (accessible and dilated common bile duct over 7 mm), laparoscopic choledochotomy had the higher
success rate, the lower complication rate, the longer operative time, and the longer postoperative hospital stay, which is
related to associated external biliary drainage. The hospital mortality included two high-risk patients (2%) and the complications
rate was 15%.
Conclusions: Laparoscopic CBDE is safe in selected patients. A stratified intraoperative surgical strategy is mandatory in deciding between
a transcystic route and choledochotomy with specific indications for each approach. When feasible, laparoscopic choledochotomy
is more efficient and safe than the transcystic route, but it is associated with a longer postoperative hospital stay, which
is due to external biliary drainage.
Received: 7 May 1996/Accepted: 19 November 1996 相似文献
975.
R. Raininko I. Elovaara E. Poutiainen A. Virta L. Valanne M. Haltia J. Lhdevirta 《European journal of neurology》1997,4(2):143-151
The course of the organic brain disease caused by human immunodeficency virus (HIV-1) was evaluated in a follow-up study. The primary material included 200 consecutive HIV-1 infected persons. Sixty-one subjects, in whom other brain-affecting factors were excluded, consented to the follow-up. They underwent 278 radiologic examinations: computed tomography, magnetic resonance imaging, or a combination of both (mean 4.6 examinations/subject). Clinical neurologic status and, in 40 subjects, cognitive performance were repeatedly evaluated. Sixteen subjects were followed up until death and 11 of them were autopsied. Median follow-up time was 27 mo (range 2.5–66 mo). The most common radiologic finding was atrophy, found in 19 subjects at study entry and developing in 10 subjects during the study. Twenty-four subjects (39%) showed the development and/or progression of atrophy. Atrophic changes progressed most rapidly in acquired immunodeficiency syndrome (AIDS), but mild developing/progressive atrophy was found even in 33% of asymptomatic or neurologically intact subjects. Cognitive and radiologic worsening were simultaneous in 6/7 subjects with declining neuropsychologic test performance. Signal intensity changes including HIV-1 leukoencephalopathy appeared in AIDS patients with clear cognitive decline. 相似文献
976.
A comparative analysis of radiological and surgical placement of central venous catheters 总被引:3,自引:1,他引:2
Kieran D. McBride Ross Fisher Neil Warnock David A. Winfield Malcolm W. Reed Peter A. Gaines 《Cardiovascular and interventional radiology》1997,20(1):17-22
Purpose To compare the differences in practice and outcome of all radiologically and surgically placed central venous catheters retrospectively
over a 2-year period simultaneously, at a single institution.
Methods A total of 253 Hickman catheters were inserted in 209 patients; 120 were placed radiologically in 102 patients and 133 were
placed surgically in 107 patients. The indication was chemotherapy in 76% of radiological and in 47% of surgical cases; the
remainder were for total parenteral nutrition and venous access.
Results There were 6 (4.5%) primary surgical failures and a further 17 (13%) surgical cases requiring multiple placement attempts.
Pneumothorax occurred once (0.8%) surgically and four times (3.3%) radiologically. There were no radiological primary misplacements
but there were five (3.7%) surgical ones. Catheter or central vein thrombosis occurred in four (3.3%) radiological and five
(3.7%) surgical cases. The rate of infection per 1000 catheter-days was 1.9 in radiologically placed catheters and 4.0 in
surgically placed ones (p<0.001). Average catheter life-span was similar for the two placement methods (100±23 days).
Conclusion Radiological placement is consistently more reliable than surgical placement. There are fewer placement complications and
fewer catheter infections overall. 相似文献
977.
The risk of contracting infectious diseases from patients with either serious or even fatal consequences has led to considerable changes in dental practice in the last few years. A key step in infection control is to prevent contact between the dentist's skin and the patient's blood and saliva by wearing gloves. The practice initially requires some patience and tolerance but then has few disadvantages. This paper reports a case where there were adverse effects to the patient from the dentist wearing gloves. 相似文献
978.
笔者提出了对Reed-Frost模型的学术评论,并新建了一种Reed-Frost模型的改进模型。该改进模型全面考虑了隐性感染者的产生、传染作用及向免疫者的转化。应用这个模型,模拟了NewEngland的麻疹流行和中国上海市某保育院的水痘流行,结果颇为理想。该模型包括了基本的流行要因,故能用以解释流行过程,并可帮助流行病学工作者理解隐性感染在传染病流行过程中的作用。 相似文献
979.
The authors describe their preliminary experience with the use of superparamagnetic magnetic resonance (MR) imaging contrast media for suppression of signal from flowing blood. The goal of this work was to determine if a superparamagnetic contrast agent could successfully eliminate blood signal during cardiac-gated MR imaging, thereby eliminating or reducing flow artifacts associated with the complex and variable hemodynamics within the heart chambers. Imaging and data analysis were performed in 17 dogs subjected to experimental myocardial infarction as part of a parallel project. Six doses (0.2, 1, 2, 3.5, 4, 5, and 10 mg/kg) of AMI-25, an experimental contrast agent, were used in the study. Spin-echo imaging was performed immediately before and every 5 minutes (for an average of 25 minutes) after bolus injection of the contrast agent. Variations in the image signal-to-noise ratio relative to a baseline (before injection of contrast agent) image were assessed as a function of dose and time. Preliminary results suggest that a considerable reduction in blood flow artifacts and, hence, increases in image signal-tonoise ratio can be achieved at doses greater than or equal to 3.5 mg/kg, for approximately 20 minutes after injection. Doses equal to or less than 2 mg/kg and images obtained more than 20 minutes after injection (regardless of dose) did not reliably show hemodynamic artifact suppression. 相似文献
980.
The objectives of this study were to compare the ability of T1-weighted (T1W), proton density/T2-weighted (PD/T2W), and fat saturation (FS) PD/T2W magnetic resonance (MR) sequences for depiction of the knee collateral ligaments and related injuries, and to compare MR findings with clinical findings. Ten subjects with normal knee ligaments and 64 patients with suspected collateral ligament injuries underwent coronal T1W, PD/T2W, and FS PD/T2W imaging. Abnormalities ranged from edema surrounding the collateral ligaments (grade I) to complete disruption of ligamentous fibers (grade III). FS PD/T2W images improved definition of the medial collateral ligament (MCL) and lateral collateral ligament (LCL) compared with other sequences in 78% and 81% of patients, respectively. While the apparent grade of collateral ligament injury was similar with all pulse sequences in most patients, depiction of such injury was usually most conspicuous on FS PD/T2W images (MCL, 92% of patients; LCL, 38% of patients). In no patients were clinically diagnosed collateral ligament injuries undetected or understaged with MR imaging. MR findings indicated higher-grade MCL and LCL injuries than did clinical examination in 24 and 15 patients, respectively. 相似文献