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   9255篇
  免费   940篇
  国内免费   12篇
耳鼻咽喉   164篇
儿科学   377篇
妇产科学   199篇
基础医学   1247篇
口腔科学   111篇
临床医学   930篇
内科学   1563篇
皮肤病学   347篇
神经病学   1014篇
特种医学   255篇
外科学   1258篇
综合类   229篇
一般理论   5篇
预防医学   1227篇
眼科学   130篇
药学   668篇
中国医学   4篇
肿瘤学   479篇
  2021年   100篇
  2020年   68篇
  2019年   111篇
  2018年   129篇
  2017年   123篇
  2016年   96篇
  2015年   113篇
  2014年   186篇
  2013年   285篇
  2012年   324篇
  2011年   360篇
  2010年   206篇
  2009年   195篇
  2008年   389篇
  2007年   478篇
  2006年   411篇
  2005年   364篇
  2004年   366篇
  2003年   359篇
  2002年   347篇
  2001年   336篇
  2000年   402篇
  1999年   318篇
  1998年   151篇
  1997年   99篇
  1996年   111篇
  1995年   106篇
  1994年   98篇
  1993年   93篇
  1992年   271篇
  1991年   220篇
  1990年   255篇
  1989年   209篇
  1988年   211篇
  1987年   191篇
  1986年   176篇
  1985年   205篇
  1984年   130篇
  1983年   90篇
  1982年   100篇
  1981年   70篇
  1980年   76篇
  1979年   115篇
  1978年   100篇
  1977年   77篇
  1976年   89篇
  1975年   80篇
  1974年   94篇
  1973年   95篇
  1972年   75篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
Oxygen-free radical production and reperfusion injury are complex mechanisms. New and improved methods for maximizing the benefits of reperfusion while minimizing reperfusion injury are on the horizon in the 1990s. Critical care nurses play a crucial role in the assessment, planning, and intervention of patients experiencing the deleterious effects of free radicals and reperfusion injury. Thus, a sound knowledge base in the pathophysiology of reperfusion injury, the detrimental effects of free radicals, and the potential benefits of free-radical scavengers is essential.  相似文献   
72.
Our objective was to determine the extent to which lower urinary tract symptoms affect the general health status of men and contribute to the decision to undergo surgery. A cross-sectional population survey using postal questionnaires was conducted in the North West Thames health region, followed by a prospective cohort study of men undergoing prostatectomy (North West Thames and Oxford regions). The subjects in the first survey were 221 men aged 55 and over with previously reported mild, moderate or severe urinary symptoms; subjects in the second study were 388 men undergoing prostatectomy. Main outcome measures were selfreported symptom severity, bothersomeness and general health status (Nottingham Health Profilie, Part 1). The response rate among eligible responders in the population survey was 85.7%. Increasing symptom severity was associated with worsening NHP scores for energy, emotional reactions, sleep and physical mobility (p<0.01). Increasing bother-someness of symptoms was associated with emotional reactions, sleep and pain (p<0.05). Men undergoing surgery reported worse health status than men in the population with the same severity of symptoms as regards emotional reactions, energy and pain. For a given level of symptom severity, the impact of those symptoms on aspects of a man's general health status may be the determinant of seeking and undergoing surgery. Greater understanding of the factors that affect a man's response to his symptoms is needed in interpreting the decision to seek and accept treatment.  相似文献   
73.
Case notes of patients admitted to hospital or seen in the casualty department following an overdose were assessed in a standardized way. The medical records were deficient in several important areas, especially for those patients seen in casualty and not referred to a psychiatrist. If only selected patients were to be assessed by psychiatrists, closer monitoring of the psychiatric assessments and management initiated by junior medical staff would be required. Although the poor records may reflect lack of motivation as much as lack of education, there was no significant relationship between the doctors' attitudes towards self-poisoning patients in general and the standard of their assessments.  相似文献   
74.
Harvey Cushing was a man of many talents. Not only was he a premier surgeon and scientist, but a prolific author and artist as well. In this paper, we present two postoperative sketches of pediatric brain tumors drawn by Dr. Cushing. These sketches are representative of drawings which accompany many of his operative notes at the Peter Bent Brigham Hospital. About 25% of Cushing's surgical sketches depict operations performed on children. The most commonly drawn childhood tumors were craniopharyngiomas and gliomas of the brain stem and cerebellum. These drawings reveal how Cushing maintained detailed records of his surgical experience. It is clearly evident from these records that Dr. Cushing gained substantial experience in the treatment of pediatric brain tumors.  相似文献   
75.
In an effort to find a replacement for the iv antiarrhythmic drug lidocaine having reduced systemic and central nervous system effects, activity against supraventricular as well as ventricular arrhythmias, and a biological half-life of less than 15 min, derivatives of the orally active class Ic clinical agent 2,6-bis(1-pyrrolidinylmethyl)-4-benzamidophenol, 1 (ACC-9358), were synthesized and tested. Compounds with ester groups attached to the phenyl ring were either weakly active or toxic. Replacement of the formanilide function with alkyl esters afforded compounds with antiarrhythmic activity in the range of 1. When the ester carboxyl was separated from the bis(aminomethyl)phenol by methylene units, very short half-lives were observed in human blood. In general, these compounds also had low lipophilic character.  相似文献   
76.
77.
Eight LEW rat recipients possessing long-term-surviving (206-701 days) LBN vascularized hind limb allografts (CTAs) were tested for donor-host lymphoid chimerism. The recipients received various cyclosporine (CsA) treatment protocols in order to induce indefinite CTA acceptance. Histological examination of long-term-surviving CTAs demonstrated normal-appearing bone marrow in the donor limb. Lymphocytes isolated from host hemopoietic tissues (peripheral blood and/or spleen) by ficoll-hypaque density gradient centrifugation were tested against LEW-anti-BN antisera. Comparisons were made to standard curves employing various known concentrations of LBN and LEW cell combinations. The level of lymphocyte agglutination (dependent variable) showed a significant (P less than 0.025-0.005) linear relationship to the concentration of LBN donor cells (independent variable) present. Lymphocyte suspensions isolated from long-term CTA host peripheral blood and/or spleen showed a mean of 19.7% (+/- 9.7-95% confidence interval) donor LBN mononuclear cells present. Thus, it appeared that lymphoid cells originated from, and/or were released from LBN donor bone marrow into the circulation, resulting in chimeric repopulation of hemopoietic tissues. The presence of donor immunocytes in these limb allograft recipients may have been beneficial, and thus could have helped contribute to the long-term CTA survival observed.  相似文献   
78.
S A Bartow  D R Pathak  W C Black  C R Key  S R Teaf 《Cancer》1987,60(11):2751-2760
A forensic autopsy series of 519 women more than 14 years old was studied for prevalence of benign, atypical, and occult malignant breast lesions. The women included Anglos (non-Hispanic whites), Hispanics, and American Indians from New Mexico and Eastern Arizona. These three ethnic/racial groups are at markedly different risk for the development of breast cancer (Anglo 89 of 100,000 women per year, Hispanic 45.5, and American Indian 24.9. There were striking ethnic/racial and age-related differences in both the prevalence and magnitude of all forms of nonproliferative and proliferative fibrocystic disease. The various subsets of fibrocystic disease were highly associated with each other. Such lesions as apocrine metaplasia, sclerosing adenosis, and lobular microcalcification showed as much difference according to ethnic/racial background and age as the more common cystic change and duct epithelial hyperplasia. Atypical lobular and ductal hyperplasia, carcinoma in situ, and occult invasive carcinoma were uncommon and also occurred in ethnic/racial groups in a pattern that parallels the cancer risk in those groups.  相似文献   
79.
Suppression of host-cell-mediated immunity is a hallmark feature of Yersinia pseudotuberculosis infection. To better understand this process, the interaction of Y. pseudotuberculosis with macrophages and the effect of the virulence plasmid-encoded Yersinia tyrosine phosphatase (YopH) on the oxidative burst was analyzed in a chemiluminescence assay. An oxidative burst was generated upon infection of macrophages with a plasmid-cured strain of Y. pseudotuberculosis opsonized with immunoglobulin G antibody. Infection with plasmid-containing Y. pseudotuberculosis inhibited the oxidative burst triggered by secondary infection with opsonized bacteria. The tyrosine phosphatase activity of YopH was necessary for this inhibition. These results indicate that YopH inhibits Fc receptor-mediated signal transduction in macrophages in a global fashion. In addition, bacterial protein synthesis was not required for macrophage inhibition, suggesting that YopH export and translocation are controlled at the posttranslational level.  相似文献   
80.
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