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   1294篇
  免费   189篇
  国内免费   20篇
耳鼻咽喉   20篇
儿科学   57篇
妇产科学   20篇
基础医学   92篇
口腔科学   38篇
临床医学   211篇
内科学   276篇
皮肤病学   108篇
神经病学   58篇
特种医学   133篇
外科学   187篇
综合类   94篇
现状与发展   30篇
预防医学   53篇
眼科学   15篇
药学   38篇
中国医学   3篇
肿瘤学   70篇
  2024年   19篇
  2023年   179篇
  2022年   13篇
  2021年   18篇
  2020年   55篇
  2019年   21篇
  2018年   52篇
  2017年   45篇
  2016年   39篇
  2015年   56篇
  2014年   83篇
  2013年   62篇
  2012年   33篇
  2011年   37篇
  2010年   74篇
  2009年   92篇
  2008年   28篇
  2007年   51篇
  2006年   20篇
  2005年   19篇
  2004年   13篇
  2003年   16篇
  2002年   15篇
  2001年   12篇
  2000年   14篇
  1999年   28篇
  1998年   35篇
  1997年   51篇
  1996年   40篇
  1995年   35篇
  1994年   29篇
  1993年   34篇
  1992年   10篇
  1991年   10篇
  1990年   13篇
  1989年   22篇
  1988年   21篇
  1987年   14篇
  1986年   5篇
  1985年   11篇
  1984年   4篇
  1983年   4篇
  1982年   9篇
  1981年   10篇
  1980年   12篇
  1978年   5篇
  1977年   3篇
  1976年   13篇
  1975年   10篇
  1974年   3篇
排序方式: 共有1503条查询结果,搜索用时 15 毫秒
991.
Background Human nail clippings are increasingly used in epidemiological studies as biomarkers for assessing diet and environmental exposure to trace elements or other chemical compounds. However, little is known about the growth rate of human nails. Objective To estimate the average growth rate of fingernails and toenails and examine factors that may influence nail growth rate. Methods Twenty‐two healthy American young adults marked their nails close to the proximal nail fold with a provided nail file following a standardized protocol, and recorded the date and the distance from the proximal nail fold to the mark. One to three months later, participants recorded the date and distance from the proximal nail fold to the mark again. Nail growth rate was calculated based on recorded distance and time between the two measurements. Results Average fingernail growth rate was faster than that of toenails (3.47 vs. 1.62 mm/month, P < 0.01). There was no significant difference between right and left fingernail/toenail growth rates. The little fingernail grew slower than other fingernails (P < 0.01); the great toenail grew faster than other toenails (P < 0.01). Younger age, male gender, and onychophagia were associated with faster nail growth rate; however, the differences were not statistically significant. Conclusion Nail growth rates have increased compared with previous estimates conducted decades ago. Toenail clippings may reflect a long exposure time frame given the relatively slow growth rate.  相似文献   
992.
Background Only a few studies characterized cutaneous non‐tuberculous Mycobacterium (NTM) infections in this region of the world . Objective The aim of this study was to describe the epidemiological, clinical and histological findings of cutaneous NTM infections in Lebanon. Patients/Methods Retrospective study of 17 patients (19 histological specimens) diagnosed with cutaneous NTM infections and confirmed by culture‐based partial sequencing of the 16S rRNA gene at the American University of Beirut Medical Center between 2005 and 2008. Results Of 17 cases, 14 were caused by Mycobacterium marinum. All patients were immunocompetent except for one. Clinically, the most common presentation was multiple sporotrichoid lesions over an extremity (8/17). Many patients had peculiar presentations including bruise‐like patches, herpetiform lesions, annular ulcerated plaques, symmetrical nodules over the buttocks and locally disseminated lesions with surrounding pale halo. Almost all patients cleared their infection on either minocycline or clarithromycin monotherapies. Histologically, a dermal small vessel proliferation with mixed inflammation (granulation tissue‐like changes) was identified in 58% of specimens. The most common type of granulomatous inflammation was the suppurative (47%) followed by the tuberculoid (30%), sarcoidal (11%), and palisading (5%) types. Lichenoid granulomatous dermatitis was noted in 42% of cases. Special staining highlighted mycobacteria in only two specimens. Conclusions The incidence of cutaneous NTM infections is high in our area. Many patients had peculiar clinical presentations. Our study is the second to report the common presence of granulation tissue‐like changes as a good histological indicator of cutaneous NTM infections. Minocycline and clarithromycin remain the drugs of choice in our area.  相似文献   
993.
A clinical trial was conducted in order to prove the efficacy of a solution containing 50 g/1 of plantain flour and 3. 5 g/1 of sodium chloride (NaCl) for the rehydration of children with acute diarrheal diseases. 121 children were given WHO-ORS (Group A) and 117 a plantain flour-based solution (Group B). Rehydration was successful in 85. 9% in Group A and 88. 0% in Group B ( p = 0. 634). Rehydration was completed in 5. 28 h (SD 1. 99) in Group A and in 4. 88 h (SD 2. 11) in Group B ( p = 0. 132). The average solution intake for rehydration was 24. 56ml/kg/h (SD 10. 12) in Group A and 21. 17ml/kg/h (SD 9. 35) in Group B ( p = 0. 00782). The mean stool output during rehydration was 8. 45g/kg/h (SD 9. 72) in Group A and 4. 69 g/kg/h (SD 4. 98) in Group B ( p = 0. 00053). Decrease in blood levels of sodium and potassium occurred in some children in group B. The plantain flour-based solution proved effective for the treatment of dehydration due to acute diarrheal diseases and should be considered as an alternative when standard WHO-ORS is not available.  相似文献   
994.
995.
Development of virtual CT cholangiopancreatoscopy   总被引:15,自引:0,他引:15  
  相似文献   
996.
Background: A significant number of soldiers suffer serious injuries or die in the process of demining and a protective device is necessary in such operations.  相似文献   
997.
998.
Duplications or deletions are present in a high percentage of the gametes produced by individuals carrying balanced translocations. Preimplantation genetic diagnosis was used to examine chromosome balance in embryos from a patient having a reciprocal translocation within the short arms of chromosomes 5 and 8 (46,XX,t(5;8)(p13;p23)). This woman has two sisters with the translocation unbalanced, resulting in a partial trisomy for chromosome 5 and partial monosomy for chromosome 8 (46,XX,-8, +der(8)t(5;8)(p13;p23)) with associated mental retardation and physical abnormalities. The patient and her husband desired to have children without the abnormal chromosome balance and wished to reduce the likelihood of spontaneous abortion or need for therapeutic abortion. Fluorescence in-situ hybridization (FISH) probes for the alpha-satellite region of chromosome 8 and for a region on the short arm of chromosome 5 (5p15.2) were tested initially on lymphocytes from the patient and her sisters. The hybridization signal for chromosome 5 was detected in the expected two copies for the patient and three copies for the sisters in 87% of the cells. Two hybridization signals for chromosome 8 were detected in 96% of the cells from all individuals. Additional probe testing was done using blastomeres from polyspermic embryos. The couple then proceeded with a stimulated in- vitro fertilization (IVF) cycle and biopsies were done on 13 embryos at the 7-10-cell stage using a method of zona drilling and fluid displacement. Diagnosis was possible on at least one blastomere for nine embryos. Three embryos had nuclei with three hybridization signals for chromosome 5, three had fewer than two signals for one or both chromosomes, one was mosaic, and two had two signals for each chromosome. The latter were transferred to the patient, but pregnancy was not achieved. The results demonstrate that preimplantation genetic diagnosis for patients with reciprocal translocations can be used to identify embryos having normal chromosome balance. The potential advantages and limitations of this approach are discussed.   相似文献   
999.
1000.
Background: Regional Trauma Centre in the northern India receives the mortal remains of all fallen soldiers for embalming. Non enemy action deaths during counter insurgency operations (CI Ops) were analysed for planning preventive measures.  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