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   628篇
  免费   109篇
  国内免费   7篇
耳鼻咽喉   1篇
儿科学   22篇
妇产科学   8篇
基础医学   89篇
口腔科学   17篇
临床医学   86篇
内科学   80篇
皮肤病学   14篇
神经病学   22篇
特种医学   123篇
外科学   25篇
综合类   36篇
预防医学   35篇
眼科学   3篇
药学   41篇
中国医学   9篇
肿瘤学   133篇
  2022年   5篇
  2021年   12篇
  2020年   10篇
  2019年   20篇
  2018年   30篇
  2017年   20篇
  2016年   25篇
  2015年   17篇
  2014年   27篇
  2013年   36篇
  2012年   21篇
  2011年   31篇
  2010年   28篇
  2009年   28篇
  2008年   33篇
  2007年   27篇
  2006年   16篇
  2005年   16篇
  2004年   32篇
  2003年   27篇
  2002年   36篇
  2001年   24篇
  2000年   12篇
  1999年   17篇
  1998年   32篇
  1997年   14篇
  1996年   13篇
  1995年   12篇
  1994年   15篇
  1993年   17篇
  1992年   4篇
  1991年   3篇
  1989年   8篇
  1988年   7篇
  1987年   4篇
  1986年   7篇
  1985年   4篇
  1984年   4篇
  1983年   6篇
  1982年   6篇
  1981年   4篇
  1980年   4篇
  1979年   3篇
  1978年   5篇
  1977年   2篇
  1976年   2篇
  1975年   3篇
  1970年   3篇
  1969年   2篇
  1967年   2篇
排序方式: 共有744条查询结果,搜索用时 11 毫秒
51.
A double-blind, randomized study was performed to compare discomfort and pain associated with the use of iopamidol and Hypaque (diatrizoate sodium and diatrizoate meglumine) during iliofemoral runoff arteriography in 33 patients. Iopamidol caused substantially less discomfort and pain. The evaluation was helped by audiotaping the study and comparing patients' vocal responses to injections of these materials.  相似文献   
52.
53.
Large cell transformation of mycosis fungoides (MF) is an uncommon phenomenon. We present a case of CD30‐positive large cell transformation and discuss its possible pathophysiology. A 74 year‐old male with a 36‐year history of patch stage MF presented with a 3‐month history of right chest cellulitis that was refractory to IV antibiotic treatment. Skin biopsies from his thigh demonstrated a patchy dermal infiltrate of irregular and hyperchromatic lymphocytes and epidermotropism. The majority of the infiltrate was positive for CD4, CD3, CD2, and negative for CD7. Only 10% were positive for CD25 and CD8. Biopsies obtained from the ulcerated chest nodules showed a dermal infiltrate of large and pleomorphic lymphoid cells with prominent nucleoli. These large lymphoid cells were strongly positive for CD3, CD30, CD25, CD2 and UCHL‐1. Occasional cells were positive for CD4 and CD20. They were negative for ALK‐1, TIA‐1, CD7, CD8, and CD15. T‐gamma receptor gene rearrangement analyses by polymerase chain reaction demonstrated a clonal process with similar rearrangement patterns identified in the patch stage MF as well as in large cell transformation areas. Examinations of his peripheral blood and bone marrow were negative. The patient had tolerated one cycle of CHOP chemotherapy.  相似文献   
54.

BACKGROUND:

Documenting the performance of gynecologic screening in actual practice settings is difficult to achieve. In the current study, the screening performance of 11 individual cytotechnologists as well as that of the overall laboratory over 2 consecutive time periods was examined using the rapid prescreening (RPS) method.

METHODS:

RPS was performed by all cytotechnologists in a single laboratory over 2 separate 8‐month periods. The sensitivity of screening for individual and groups of cytotechnologists was examined. For purposes of comparison, cytotechnologists were divided into 2 groups: screeners with an overall routine sensitivity ≥95% and screeners with an overall sensitivity <95%.

RESULTS:

Atypical squamous cells (ASC) were used as a threshold, and routine screening sensitivity was found to vary from 68.3% to 96.8%. The overall sensitivity of the laboratory for RPS and routine screening was 43.6% and 88.4%, respectively. Over time, the overall laboratory sensitivity of routine screening improved from 85.3% to 91.3% (P = .01). During this same time frame, the sensitivity of the screeners with an overall sensitivity <95% improved from 79.3% to 91.2% (P < .001), whereas the sensitivity of screeners with an overall routine sensitivity ≥95% remained the same (96.1% to 96.4%; P = .6).

CONCLUSIONS:

In addition to improved overall performance of the laboratory by detecting and correcting errors, the results of the current study indicate that using RPS consistently over time might play a role leading to improved performance of cytotechnologists with an overall routine sensitivity <95% but not of cytotechnologists with an overall routine sensitivity ≥95%. Cancer (Cancer Cytopathol) 2009. © 2009 American Cancer Society.  相似文献   
55.
螺旋CT三维成像术-SSD的应用   总被引:2,自引:0,他引:2  
目的:对三维成像技术SSD的临床应用进行探讨。材料与方法:开展SSD病人20例,其中男13例,女7例,年龄24-69岁,采用西门子Balance CT机,进行容积扫功,层厚2mm-4mm,螺距1-2,三维重建图像后处理采用SSD并采取多个角度观察,分析。结果:20例SSD检查成像良好。结论:SSD是非创伤性影像检查,具有安全、简便、价廉的优点,是一种适合临床广泛应用的影像检查方法。  相似文献   
56.
Preclinical investigations can start with preliminary in vitro studies before using animal models. Following this approach, the number of animals used in preclinical acute toxicity testing can be reduced. In this study, we employed an in-house validated in vitro cytotoxicity test based on the Spielmann approach for toxicity evaluation of the lignan grandisin, a candidate anticancer agent, and its major metabolite, the 4-O-demethylgrandisin, by neutral red uptake (NRU) assay, on mouse fibroblasts Balb/c 3T3 cell line. Using different concentrations of grandisin and its major metabolite (2.31; 1.16; 0.58; 0.29; 0.14; 0.07; 0.04; 0.002 μM) in Balb/c 3T3-A31 NRU cytotoxicity assay, after incubation for 48 h, we obtained IC50 values for grandisin and its metabolite of 0.078 and 0.043 μM, respectively. The computed LD50 of grandisin and 4-O-demethylgrandisin were 617.72 and 429.95 mg/kg, respectively. Both were classified under the Globally Harmonized System as category 4. Since pharmacological and toxicological data are crucial in the developmental stages of drug discovery, using an in vitro assay we demonstrated that grandisin and its metabolite exhibit distinct toxicity profiles. Furthermore, results presented in this work can contribute to reduce the number of animals required in subsequent pharmacological/toxicological studies.  相似文献   
57.
纵隔低密度肿块病变CT诊断   总被引:12,自引:0,他引:12  
目的:提高纵隔低密度肿块病变CT诊断水平。材料与方法:回顾性分析51例经临床、手术及病理确诊纵隔低密度肿块变的CT表现。结果:(1)不同纵隔低密度肿块病变均有其较特定的发病部位;(2)含脂肪密度肿块病变包括囊性畸胎瘤,脂肪瘤 低密度肿块为包括囊性淋巴管瘤,胸腺囊肿,支气管囊肿,心包囊肿,神经纤维瘤囊性变,囊性畸胎瘤,椎旁脓肿;(4)含气及水样密度肿块包括食管癌术后胸腔内胃,食管憩室;(5)2例胸腺  相似文献   
58.
59.
We have used cone-beam computed tomographic (CT) images to retrospectivelyevaluate the influence of sex, skeletal class, facial type, and the presence of septa on the volume of the sphenoid sinus in 172 images from 85 men (mean (SD) age 28 (2) years) and 87 women (mean (SD) age 30 (1) years). Skeletal class and facial type were calculated for each patient from multiplanar reconstructions using NemoCeph® software. Volumetric analysis of the sphenoid sinus was made with the help of the ITK-SNAP® 3.4.0 segmentation software, while the presence or absence of septa in the sphenoid sinus was evaluated with the Carestream 3D Imaging® software 3.4.3. We analysed the results using two-way ANOVA, Student’s independent sample t test, and Fisher’s exact test, as appropriate, and probabilities of <0.05 were accepted as significant. Sex (p = 0.0946), facial type (p = 0.790), and skeletal class (p = 0.120) had no significant influence on the volume of the sphenoid sinus, and nor did the volumes of the right and left sphenoid sinuses (p = 0.0923), or the presence of a septum within the sinus (p = 0.330) in its volume.  相似文献   
60.
Antisense oligonucleotides (AONs) are being developed as RNA therapeutic molecules for Duchenne muscular dystrophy. For oligonucleotides with the 2′-O-methyl-phosphorothioate (2OMePS) RNA chemistry, proof of concept has been obtained in patient-specific muscle cell cultures, the mouse and dog disease models, and recently by local administration in Duchenne patients. To further explore the pharmacokinetic (PK)/pharmacodynamic (PD) properties of this chemical class of oligonucleotides, we performed a series of preclinical studies in mice. The results demonstrate that the levels of oligonucleotides in dystrophin-deficient muscle fibers are much higher than in healthy fibers, leading to higher exon-skipping levels. Oligonucleotide levels and half-life differed for specific muscle groups, with heart muscle showing the lowest levels but longest half-life (~46 days). Intravenous (i.v.), subcutaneous (s.c.), and intraperitoneal (i.p.) delivery methods were directly compared. For each method, exon-skipping and novel dystrophin expression were observed in all muscles, including arrector pili smooth muscle in skin biopsies. After i.v. administration, the oligonucleotide peak levels in plasma, liver, and kidney were higher than after s.c. or i.p. injections. However, as the bioavailability was similar, and the levels of oligonucleotide, exon-skipping, and dystrophin steadily accumulated overtime after s.c. administration, we selected this patient-convenient delivery method for future clinical study protocols.  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