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   1409984篇
  免费   104505篇
  国内免费   4970篇
耳鼻咽喉   17708篇
儿科学   45858篇
妇产科学   38173篇
基础医学   207793篇
口腔科学   37609篇
临床医学   135792篇
内科学   274090篇
皮肤病学   27993篇
神经病学   118744篇
特种医学   51005篇
外国民族医学   384篇
外科学   194547篇
综合类   30328篇
现状与发展   1篇
一般理论   498篇
预防医学   118709篇
眼科学   30147篇
药学   104975篇
  9篇
中国医学   3619篇
肿瘤学   81477篇
  2021年   12400篇
  2019年   12978篇
  2018年   17939篇
  2017年   13545篇
  2016年   14565篇
  2015年   16740篇
  2014年   22858篇
  2013年   34990篇
  2012年   48183篇
  2011年   50987篇
  2010年   29742篇
  2009年   27298篇
  2008年   46306篇
  2007年   48753篇
  2006年   48684篇
  2005年   46985篇
  2004年   45203篇
  2003年   43086篇
  2002年   41884篇
  2001年   63466篇
  2000年   65056篇
  1999年   54293篇
  1998年   15465篇
  1997年   13966篇
  1996年   13730篇
  1995年   13065篇
  1994年   12171篇
  1993年   11443篇
  1992年   42791篇
  1991年   42010篇
  1990年   40487篇
  1989年   38372篇
  1988年   35528篇
  1987年   34490篇
  1986年   32952篇
  1985年   31368篇
  1984年   23564篇
  1983年   20118篇
  1982年   12091篇
  1979年   21242篇
  1978年   15129篇
  1977年   12364篇
  1976年   12138篇
  1975年   12445篇
  1974年   15173篇
  1973年   14822篇
  1972年   13690篇
  1971年   12732篇
  1970年   11757篇
  1969年   10724篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
A 16-year-old boy, the only affected member of the family, noticed early onset contracture of the elbows, and developed slowly progressive humeroperoneal weakness and atrophy, and bilateral equinus. The severe restriction of the forward flexion of the neck and thoracolumbar spine, resembled a rigid spine syndrome. An electrocardiogram showed atrioventricular conduction abnormalities. Muscle biopsy was consistent with mild myopathy. The overall conventional findings of a detailed electromyographic study in the limbs and erector trunci muscles, as well as the results of conduction velocity, automatic analysis of the voluntary pattern and single fiber electromyography studies were consistent with myopathy, although some atypical findings were found. The controversy about neurogenic and myopathic features in Emery-Dreifuss disease is discussed. The unspecific value of the flexion limitation of the spine, and the uncertain nosological position of the rigid spine syndrome are also commented.  相似文献   
993.
Retrograde axonal tracing and double-labelling immunofluorescence have been combined to determine the neuropeptide content of identified pilomotor neurons in the superior cervical ganglion of guinea pigs. These neurons lacked immunoreactivity to neuropeptide Y (NPY) but they generally contained low levels of immunoreactivity to prodynorphin-derived peptides, including dynorphin A(1-8), dynorphin A(1-17), and alpha-neo-endorphin. Thus pilomotor neurons are neurochemically distinct from superior cervical ganglion cells which contain immunoreactivity to NPY and prodynorphin-derived peptides and which innervate the iris and most of the vasculature in the head of guinea pigs. They are also distinct from sympathetic secretomotor neurons which lack both NPY and prodynorphin-derived peptides.  相似文献   
994.
Behavioral neurology of multi-infarct dementia   总被引:2,自引:0,他引:2  
Multi-infarct dementia (MID) is a heterogeneous entity in which a variety of cerebrovascular disorders leads to intellectual impairment. A variety of patterns of behavioral changes may be observed in MID, depression, psychosis, and personality change are common. The neurobehavioral syndromes of MID are determined by the specific arteries involved and the location and extent of tissue infarction.  相似文献   
995.
Both abuse and new uses for benzodiazepines are reviewed. The pharmacology of benzodiazepines is summarized and statistics regarding their general use are given. The question of benzodiazepine abuse is reviewed in some detail and the question of rebound, recurrence of symptoms and physiological withdrawal is differentiated. Benzodiazepines are regarded as a very safe class of drugs and the abuse potential is felt to be negligible provided that they are prescribed for appropriate conditions and monitored carefully. The dangers of alternatives to benzodiazepines such as alcohol or barbiturates is emphasized. New uses for benzodiazepines are reviewed including the use of benzodiazepines in panic disorder, as well as an adjunct in the therapy of mania and some psychotic states. Rational prescribing of benzodiazepines is encouraged and the attitude that these are dangerous and addictive drugs is discouraged and put into perspective.  相似文献   
996.
Monoclonal antibody 131I-COC183B2, developed in our laboratory and proved to fit for human treatment was injected intraperitoneally or subcutaneously in 13 patients. In 8 cases with i.p. injection the disease corresponded with the image, i.e. 3 primary ovarian epithelial cancers showed positive images, 1 ovarian Krukenberg tumor was negative and the other 4 negative images included 1 uterine myoma and 3 ovarian teratomas. In the subcutaneous injection group, 4 cases had ovarian carcinoma, surgery and chemotherapy. Two negative images corresponded with the clinical status-in good health, another negative case had metastatic left supraclavicular lymph node due to ovarian mucinous adenocarcinoma. The last negative image in this group was a case of benign ovarian teratoma which was proved after surgery. The 1 positive case was waiting to be proved by a scheduled third operation. The computer scintigram calculation of T/NT was 5.35 to 13.7. The results suggest that this monoclonal antibody can be used for radioimmunoimaging for the localization of ovarian carcinoma, which is not only helpful for clinical staging and differential diagnosis but is also a good follow-up method.
  相似文献   
997.
998.
In this report, we examine the functional significance of the molecular microheterogeneity of alpha-fetoprotein (AFP). In doing so, we have taken the direct approach of purifying the naturally occurring isomeric forms of fetal-derived AFP using a preparative anion exchange column linked to an automated fast protein liquid chromatography (FPLC) system followed by parallel testing of each isolated molecular variant for in vitro immunoregulatory activity. The data obtained demonstrate the presence of seven distinct variants of AFP as defined by their retention volumes on FPLC elution profiles, by their pIs on analytical IEF gels, and by Western blot analysis. Molecular mass determination by SDS-PAGE showed each isomer to be equivalent in size to 69,000-dalton native unfractionated AFP molecules. All the immunosuppressive activity of AFP was localized to a single variant representing only 6% of the total composition of native AFP. The immunoregulating isomer termed AFP-1 was the least acidic of the seven isolated variants with a pI of 5.1 and displayed a sialic acid content of 1 mol/mol of protein. The inhibitory activity of AFP-1 could be readily measured on T cell-dependent antibody synthesis, Con A-induced stimulation of Lyt-1+23- thymocyte DNA synthesis, and lymphokine-activated NK cell activity. All other isomers were without effect in these test systems. The immunosuppressive AFP-1 isomer also displayed the strongest growth-promoting influence on cultured bone marrow lymphocytes. There was no correlation between functional activity and degree of expression of sialic acid residues on the AFP molecules. These findings demonstrate that the immunoregulating function of AFP is confined to a distinct and relatively small subpopulation of native AFP molecules and should therefore contribute to the resolution of outstanding questions regarding the structure/function relationship of this onco-fetal glycoprotein.  相似文献   
999.
A 53-year-old woman was examined at our medical center because of progressive dysphagia of 14 days' duration and a severe inability to open her mouth and swallow saliva. A barium esophagogram showed no obstruction, but pooling of barium in the hypopharynx suggested a neuromuscular disorder. The clinical diagnosis of tetanus was confirmed by electromyography. With appropriate therapy, the patient recovered during a period of 6 weeks. This case illustrates both an uncommon cause of dysphagia and an uncommon initial manifestation of tetanus.  相似文献   
1000.
A digital test of pelvic muscle strength for evaluation of a pelvic muscle exercise (PME) program was developed with a sample of 338 incontinent women living at home. Factors of perceived pressure, alteration of the vertical plane, and time were combined to form a 7-point scale ranging from 0 to 4. Test-retest for the anteroposterior score was r = .65, p less than .01 with interrater reliability, r = .91, p less than .01. Relationship to other variables and further development of the measure are discussed.  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