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   1415篇
  免费   83篇
  国内免费   8篇
耳鼻咽喉   85篇
儿科学   40篇
妇产科学   53篇
基础医学   115篇
口腔科学   29篇
临床医学   217篇
内科学   213篇
皮肤病学   18篇
神经病学   154篇
特种医学   143篇
外科学   132篇
综合类   26篇
预防医学   147篇
眼科学   5篇
药学   76篇
中国医学   2篇
肿瘤学   51篇
  2022年   7篇
  2021年   23篇
  2020年   14篇
  2019年   26篇
  2018年   21篇
  2017年   17篇
  2016年   17篇
  2015年   31篇
  2014年   31篇
  2013年   41篇
  2012年   65篇
  2011年   47篇
  2010年   32篇
  2009年   31篇
  2008年   58篇
  2007年   51篇
  2006年   57篇
  2005年   62篇
  2004年   59篇
  2003年   45篇
  2002年   30篇
  2001年   50篇
  2000年   54篇
  1999年   44篇
  1998年   19篇
  1997年   16篇
  1996年   23篇
  1995年   19篇
  1994年   23篇
  1993年   18篇
  1992年   22篇
  1991年   27篇
  1990年   36篇
  1989年   28篇
  1988年   25篇
  1987年   21篇
  1986年   34篇
  1985年   23篇
  1984年   23篇
  1983年   17篇
  1982年   16篇
  1980年   18篇
  1979年   19篇
  1978年   17篇
  1977年   15篇
  1976年   14篇
  1975年   10篇
  1973年   10篇
  1970年   7篇
  1921年   8篇
排序方式: 共有1506条查询结果,搜索用时 15 毫秒
81.
82.
Caregiving is both an art and a science; both knowledge and skills are necessary to improve the quality of care that professionals provide. Researchers are often limited in their assessment of skill performance due to inadequate and unrealistic measurement options. Simulation using standardized patients offers researchers an objective method to evaluate skill performance. This article describes the use of simulations by researchers in their quest to measure changes in violence prevention skills after an intervention program given to nurse assistants working in long-term care facilities.  相似文献   
83.
84.
Injuries of the extra hepatic biliary tree following blunt trauma to the abdomen are rare. We present here a case of injury to the confluence of the hepatic ducts and a brief synopsis on diagnosis and management of blunt injury to the extrahepatic biliary system.  相似文献   
85.
OBJECTIVE: To identify chromosomal regions that show evidence of linkage to age-associated hearing impairment (presbycusis) in humans. DESIGN: We evaluated the genetic linkage between quantitative measures from audiometric examinations and markers from a genomewide scan in a population-based sample ascertained without respect to hearing status. PARTICIPANTS: Audiometric examinations were conducted on 2263 original cohort members and 2217 offspring cohort members of the National Heart, Lung, and Blood Institute's Framingham Heart Study. Of these, 1789 individuals were members of 328 extended pedigrees used for linkage analysis. The outcome traits for linkage analysis were pure-tone average at medium (0.5, 1.0, and 2.0 kHz) and low (0.25, 0.5, and 1.0 kHz) frequencies adjusted for cohort, sex, age, age squared, and age cubed. RESULTS: We found heritability (proportion of variance due to genes) of age-adjusted pure-tone average at medium and low frequencies to be 0.38 and 0.31, respectively. Genomewide linkage analysis identified several locations with suggestive evidence of linkage. Of particular interest are the regions 11p (maximum multipoint logarithm of odds [MLOD], 1.57), 11q13.5 (MLOD, 2.10), and 14q (MLOD, 1.55), which overlap with genes known to cause congenital deafness. CONCLUSIONS: There is evidence that genetic and environmental factors contribute to hearing loss in the mature human population. Several of the chromosomal locations identified overlap with loci known to cause congenital hearing loss. Further studies are needed to determine whether the same genes cause presbycusis and congenital hearing loss.  相似文献   
86.
We wished to determine whether the previously reported lower arterial or alveolar P(CO2) in women than men, and in luteal (LUT) compared with follicular (FOL) menstrual cycle phase would persist during normal oral contraceptive use and during early altitude exposure. Ventilation and blood gases were measured at baseline (636 mmHg approximately 5400 ft, 1650 m) and during simulated altitude at 426 mmHg ( approximately 16000 ft, 4880 m), after 1 h (A1) and during the 12th h (A12), in 18 men (once) and in 19 women twice, during LUT and FOL and in 20 women twice while on placebo (PLA) or highest progestin dose (PIL) oral contraceptives. At baseline, Pa(CO2) was significantly higher in men than all women by 3.3 mmHg. When progesterone-progestin (PRO) was elevated in women, Pa(CO2) was significantly lower than in FOL and PLA, but the latter were still significantly lower than men. At altitude the P(CO2) differences between men and women and PRO levels persisted, with PA(CO2) falling by 3.6 and 7.3 mmHg at A1 and A12 in all, indicating an equivalent increase in alveolar ventilation. The mean arterial-end tidal P(CO2) difference was never >2 mmHg in the groups, indicating no VA/Q mismatch related to gender, PRO levels or altitude. All women had higher breathing frequency than men, resulting in greater deadspace ventilation. At altitude, the mean Pa(O2) was approximately 44 mmHg (Sa(O2) approximately 79%) for all, indicating equivalent oxygenation, but alveolar-arterial P(O2) differences were greater in women than men and higher when PRO was elevated. These results show that, relative to men, women have a compensated respiratory alkalosis, accentuated with elevated PRO. However, the ventilation response to acute altitude is the same in women and men.  相似文献   
87.
PURPOSE/OBJECTIVES: To describe the caring behaviors and demands of African American women newly diagnosed with breast cancer and to consider the influence of caring on the women's decision to delay prompt diagnosis and maintain continuing treatment. DESIGN: Focused ethnographic design using photography. SAMPLE/SETTING: 13 African American women (ages 30-66) purposefully selected from two oncology clinics in the mid-South. METHODS: Ethnographic interviews (transcribed verbatim), observations at informant-selected sites, field notes, and snapshots of caring taken by the women where caring occurred were analyzed using Lelninger's phases of ethnographic analysis. FINDINGS: Major themes were (a) generic caring for others and self as meaningful and as promoting continued commitment to diagnosis and treatment, (b) generic and professional caring from others as supportive to the women in "going on," and (c) noncaring related to a "wait and see" attitude of healthcare providers and of women in delaying early diagnosis. CONCLUSIONS: African American women's caring both for and from others was supportive in seeking and continuing diagnosis and treatment. The women with cancer viewed ensuring early diagnosis and continued treatment for other women as their "mission." Delay by providers and women requires further research. IMPLICATIONS FOR NURSING PRACTICE: Nurses must advocate assertiveness for African American women in seeking help for breast cancer symptoms and in challenging providers who adopt a "wait and see" attitude when symptoms are present. Taking snapshots, in addition to fostering the research process, is suggested as a potentially helpful intervention for women as they work through their experiences during treatment for breast cancer.  相似文献   
88.
BACKGROUND: A 41-year-old premenopausal woman with newly diagnosed haemochromatosis was found to have osteopenia on screening bone mineral densitometry. METHODS AND RESULTS: Liver biopsy showed grade 3 haemochromatosis with an hepatic iron index of 4. Investigation for secondary factors for osteopenia revealed no cause. The patient was clinically and biochemically eugonadal. Following venesection of 8 L blood (4 g iron) over 17 months and calcium supplementation, her bone density rose significantly. Neck of femur bone density increased by 6.0% over 13 months and lumbar vertebral bone density increased by 7.2%. There are no previous reports of response of bone density to venesection in eugonadal patients or in women with haemochromatosis.  相似文献   
89.
W C Young  G A Gates 《The Laryngoscope》1978,88(11):1784-1788
In an attempt to find a better technique for immediate control of CSF rhinorrhea following transsphenoidal hypophysectomy, a tissue adhesive, ethyl 2-cyanoacrylate, has been used in 28 consecutive operations. The physical properties of the adhesive, its theoretical advantages, and our results are discussed.  相似文献   
90.
Factors affecting the clinical value of microscopy for acid-fast bacilli   总被引:14,自引:0,他引:14  
In order to assess the clinical value of microscopy for acid-fast bacilli (AFB), the results of 3,207 clinical specimens submitted for mycobacterial smear and culture were analyzed. Mycobacteria grew from 176 (5.5%) of the specimens, 95 (54%) of which were Mycobacterium tuberculosis. Although the overall sensitivity of the smear was low (33%), 65% of respiratory specimens yielding M. tuberculosis had positive AFB smears. Furthermore, 96% of patients with pulmonary tuberculosis from whom more than one specimen was processed had at least a single positive AFB smear. Smear sensitivity correlated well with quantitative growth; 89% of specimens yielding greater than or equal to 50 colonies per slant were smear positive. Specificity of the AFB smear was high; 89% of smear-positive specimens had positive cultures. After the results from culture-negative patients known to have active tuberculosis were eliminated from the analysis, the specificity of a positive smear rose to 98.3%. When the results of all specimens from each patient were considered in toto, the AFB smear had a predictive value of greater than or equal to 96%.  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