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   862075篇
  免费   70467篇
  国内免费   1842篇
耳鼻咽喉   12799篇
儿科学   24623篇
妇产科学   25096篇
基础医学   124204篇
口腔科学   25484篇
临床医学   75310篇
内科学   164524篇
皮肤病学   16973篇
神经病学   70068篇
特种医学   35191篇
外国民族医学   171篇
外科学   136152篇
综合类   24604篇
现状与发展   2篇
一般理论   263篇
预防医学   66863篇
眼科学   20517篇
药学   64688篇
中国医学   1593篇
肿瘤学   45259篇
  2018年   7334篇
  2015年   7722篇
  2014年   11105篇
  2013年   16774篇
  2012年   22708篇
  2011年   23821篇
  2010年   13861篇
  2009年   13058篇
  2008年   22562篇
  2007年   24613篇
  2006年   24486篇
  2005年   24132篇
  2004年   23699篇
  2003年   22827篇
  2002年   21921篇
  2001年   35822篇
  2000年   36466篇
  1999年   30895篇
  1998年   9220篇
  1997年   8545篇
  1996年   8475篇
  1995年   8006篇
  1994年   7723篇
  1992年   26658篇
  1991年   26098篇
  1990年   25617篇
  1989年   24677篇
  1988年   23219篇
  1987年   22883篇
  1986年   21740篇
  1985年   21097篇
  1984年   16385篇
  1983年   13996篇
  1982年   8854篇
  1981年   8201篇
  1980年   7671篇
  1979年   16736篇
  1978年   12114篇
  1977年   10181篇
  1976年   9328篇
  1975年   10147篇
  1974年   12641篇
  1973年   12136篇
  1972年   11538篇
  1971年   10685篇
  1970年   10218篇
  1969年   9909篇
  1968年   8900篇
  1967年   8230篇
  1966年   7653篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Psychiatric morbidity in Hobart's dependent aged   总被引:1,自引:0,他引:1  
Psychiatric morbidity in the dependent aged was studied in the elderly population of Hobart's nursing homes and long-stay hospitals. Only patients with home addresses in Hobart and who were admitted for the first time aged 70 years or over were included. Three hundred and twelve persons were interviewed with a standard interview, and an informant was interviewed when appropriate. The medical records were searched for diagnoses and drug treatments. Physical disability was rated on an ad hoc scale. Comparisons were made of the prevalence of dementia, depression and anxiety in different types of unit, and between these and two domiciliary samples, one of which received domiciliary nursing services (n = 100) and the other not (n = 100). The differential use of institutions by men and women, and a possible sex difference in the prevalence of dementia is discussed.  相似文献   
992.
993.
The effects of acute stress exposure upon cholecystokinin (CCK) and substance P (SP) concentrations in discrete hypothalamic regions of the adult male rat brain were studied. Animals were exposed to foot shock stress for periods of 2, 4, 10, 30 or 60 min duration; immediately afterwards they were decapitated; brains were frozen and subsequently microdissected. CCK and SP concentrations were assayed by a specific RIA, as were serum levels of ACTH, corticosterone, PRL, GH, LH and testosterone. Stress had no effect upon SP concentrations in the anterior or posterior parts of the arcuate nucleus (ARC), but led to elevated CCK levels in the posterior ARC following 60 min of exposure. In both the ventromedial and dorsomedial hypothalamic areas, stress induced depletions of both neuropeptides. In the anterior (but not the posterior) portions of the lateral hypothalamic area, CCK and SP concentrations were reduced by stress exposure. These studies demonstrate that discrete hypothalamic CCK and SP neuronal systems are responsive to stress. This suggests that endogenous hypothalamic CCK and SP participate, along with other neurotransmitters/neuromodulators, in the integrated hypothalamic stress response, and mediate stress-neuroendocrine interactions.  相似文献   
994.
995.
Two examples of localized primary amyloid tumor of the breast are presented, including one patient with metachronous bilateral lesions. Our findings and review of the literature indicate that this rare lesion occurs predominantly in elderly females and can be mammographically and clinically confused with carcinoma. Fine-needle aspiration biopsy can be a useful procedure to make a preliminary diagnosis. Congo red staining with prior potassium permanganate incubation confirmed the AL type of amyloid in our two cases; this might be the predominant type in the localized form involving the breast. Immunofluorescence studies demonstrated IgA, with kappa and lambda light-chain deposition within the amyloid foci in one case, and intracytoplasmic IgG with both light chains within plasma cells and amyloid deposits of the second case. Ultrastructural examination of one of the cases showed characteristic findings of straight, nonbranching fibrils of 4-9 nm, diagnostic of amyloid. From our findings and a review of the literature, we conclude that amyloid tumors of the breast can occur in three separate settings: secondary amyloidosis, systemic or multiple myeloma associated amyloidosis, and as a localized primary type having a benign course.  相似文献   
996.
After measurement of normal renal function, dog kidneys (n = 52) were subjected to 3, 15, or 30 min of normothermic warm ischemia (WI). After 24 hr of preservation by simple hypothermic storage (SHS) in a modified Collins solution, autotransplant was done and renal function was again measured beginning at 1 hr. Compared with preharvest values, kidneys with minimal (3 min) WI had significantly decreased clearances of creatinine (Cr) and para-aminohippuric acid (PAH), PAH extraction, absolute and fractional Na reabsorption, Na excretion, and urinary Na concentration; no change in urine flow rate or K excretion; and significantly increased fractional excretion of Na, K, and H2O. Compared with minimal WI, 30-min WI produced further significant decreases in clearances of Cr, PAH, and PAH extraction; and further increases in fractional excretion of Na, K, and H2O. Urine flow was also decreased by about half and urine Na concentration rose significantly. Several parameters were very significantly correlated with the length of WI, but the most reliable index was the fractional reabsorption of Na. When several functional parameters were used together, kidneys with significant (30 min) WI prior to preservation could be identified with a high degree of statistical reliability.  相似文献   
997.
998.
Of the nearly 600 Vietnam War American prisoners of war (POWs), 332 were United States Air Force flyers who had suffered maltreatment, confinement, and boredom for months to years. We examined four coping styles of USAF POWs related to successful/unsuccessful coping and resistance stance during captivity and cognitive integration of the prisoner experience after repatriation. Findings indicate that no coping style is clearly associated with an increased risk of postrepatriation psychiatric morbidity. Postrepatriation MMPI scales indicate personality differences between individuals in the various coping groups.  相似文献   
999.
Morphologic study of the spinal cord of a patient with generalized motor deficits revealed changes in the anterior horns characterized by the selective loss of large motor neurons, gliosis and the abnormal accumulation of 10 nm filaments which appeared as argyrophilic spheroids in the perikarya and axons of motor neurons. The ventral roots were predominantly affected and showed a variable loss of axons. The remaining axons displayed prominent onion-bulb formations, frequent axonal sprouting and occasionally evidence of active demyelination. The coexistence of a demyelinating motor radiculopathy and anterior horn changes simulating those of amyotrophic lateral sclerosis (ALS) may contribute to our understanding of the unresolved question of whether the neuronal perikaryon or its axon is the primary target in the pathogenesis of ALS. These observations also indicate that a rigid separation of pathogenetic mechanisms into neuronopathy, axonopathy and myelinopathy may not be always possible.  相似文献   
1000.
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