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   174182篇
  免费   8106篇
  国内免费   1214篇
耳鼻咽喉   2515篇
儿科学   3129篇
妇产科学   3840篇
基础医学   25461篇
口腔科学   3555篇
临床医学   16139篇
内科学   32707篇
皮肤病学   4672篇
神经病学   12917篇
特种医学   8639篇
外科学   23198篇
综合类   2195篇
现状与发展   5篇
一般理论   84篇
预防医学   10089篇
眼科学   4593篇
药学   14492篇
  38篇
中国医学   1707篇
肿瘤学   13527篇
  2024年   812篇
  2023年   1229篇
  2022年   2974篇
  2021年   5208篇
  2020年   2848篇
  2019年   4049篇
  2018年   4708篇
  2017年   3498篇
  2016年   4558篇
  2015年   6135篇
  2014年   7462篇
  2013年   8985篇
  2012年   13524篇
  2011年   13081篇
  2010年   7771篇
  2009年   6485篇
  2008年   9733篇
  2007年   9564篇
  2006年   8780篇
  2005年   8337篇
  2004年   7391篇
  2003年   6443篇
  2002年   5627篇
  2001年   4447篇
  2000年   4072篇
  1999年   3298篇
  1998年   1345篇
  1997年   1024篇
  1996年   963篇
  1995年   876篇
  1994年   758篇
  1993年   661篇
  1992年   1589篇
  1991年   1585篇
  1990年   1366篇
  1989年   1247篇
  1988年   1166篇
  1987年   1047篇
  1986年   1018篇
  1985年   889篇
  1984年   657篇
  1983年   571篇
  1982年   408篇
  1981年   385篇
  1980年   349篇
  1979年   521篇
  1978年   411篇
  1977年   391篇
  1976年   342篇
  1974年   361篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The effects of alminoprofen, a nonsteroidal anti-inflammatory agent, on the experimental animal models of allergic reactions were examined and compared with those of ibuprofen. Alminoprofen at 30 mg/kg given intraduodenally significantly suppressed passive anaphylactic bronchoconstrictions, while ibuprofen did not at the same doses. In vitro studies revealed that alminoprofen, in contrast to ibuprofen, exerted an inhibitory effect on arachidonate 5-lipoxygenase activity which initiates the bio-synthesis of leukotrienes. Alminoprofen inhibited arachidonic acid-induced ear edema in mice and homologous passive cutaneous anaphylaxis in rats at high doses, while ibuprofen did not at the high doses. From its characteristic feature of inhibitory effects on 5-lipoxygenase activity and the experimental model of type I allergic reaction, it is suggested that alminoprofen is a new type of nonsteroidal anti-inflammatory agent.  相似文献   
72.
Macrobrachium rosenbergii that had been exposed individually for 24 h to 0 (control), 2, 5, 10 mg/L nitrite-N (nitrite as nitrogen) at 4.3 and 7.7 pH levels were examined for hemolymph nitrite-N, oxyhemocyanin, protein, acid–base balance, ion concentrations, and ammonia-N (ammonia as nitrogen) excretion. Hemolymph oxyhemocyanin, protein, pH, HCO3 , TCO2, osmolality, and ion concentrations were inversely related to ambient nitrite-N concentration and were lower at pH 4.3. However, hemolymph nitrite-N, PO2 and PCO2 levels, and ammonia-N excretion were directly related to ambient nitrite-N, and were higher at pH 4.3. Ambient nitrite-N and pH level interacted to cause changes in hemolymph nitrite-N, oxyhemocyanin, protein, PO2, and pH levels. It is concluded that for M. rosenbergii following nitrite exposure, the incorporated nitrite causes a decrease of pH and an increase of PO2 in the hemolymph where it reduces oxyhemocyanin level; disturbs nitrogen excretion, ion regulation, and respiratory gas exchange; and may lead to a decrease of oxygen-carrying capacity, which are affected more at low pH. Received: 31 August 1996/Accepted: 9 July 1997  相似文献   
73.
74.
Tumor necrosis factor (TNF) was produced in mice bearing Ehrlich ascites tumor (EAT) by priming with zymosan and subsequently challenging with lipopolysaccharide. The optimal conditions for the in vivo production of TNF in treating EAT bearing mice were established. The endotoxin shock induced in mice during TNF production could be minimized by the combined administration of sulindac and mannoheptulose. The endogenous TNF produced could suppress proliferation of EAT cells as well as prolong the survival time of mice bearing small tumors.  相似文献   
75.
Rett's syndrome(RS) is a progressive neurodegenerative disorder characterized by exclusive occurrence in females, autistic behavior, dementia, gait ataxia, loss of purposeful use of the hands with stereotypic hand movement, and seizures. Initially RS was considered to be very rare; however, recent reports suggest that the prevalence is considerably higher and occurrence is world-wide. Because the pathophysiological process remains unknown, the diagnosis of RS is based mainly on its characteristic clinical features and course. We experienced two cases of RS which, to our knowledge, are the first reported in Korea. It is quite possible that many patients with RS not yet being diagnosed in Korea.  相似文献   
76.
Quality of life in adult survivors of lung,colon and prostate cancer   总被引:22,自引:0,他引:22  
In a cross-sectional study design, a disease free sample of 57 lung, 117 colon, and 104 prostate cancer survivors who represented short, intermediate and long-term survivors completed a detailed assessment of quality of life (QOL) and rehabilitation needs using the CAncer Rehabilitation Evaluation System (CARES). Demographic and medical data, social support, and a global QOL rating were also assessed. Lung cancer patients showed no differences in QOL with respect to their period of survival. QOL improved for survivors of colon cancer as they lived for longer periods, but declined with time for survivors of prostate cancer. The best predictor of QOL for all groups was KPS, although other variables such as type of hospital, gender, and work status were predictive for survivors of colon cancer. For survivors of prostate cancer comorbidity with other medical illnesses, time since diagnosis and comorbidity due to psychiatric difficulties were predictive of QOL. All groups had significant rehabilitation problems in the domains of physical, psychosocial, sexual, medical interaction, and marital relationships. Lung cancer survivors had more problems than the other cancer survivors. We conclude that patients who survive cancer do not return to a state of normal health. They demonstrate a variety of difficulties with which they must cope as they continue to survive. Greater efforts need to be made early in diagnosis and treatment to understand rehabilitation problems and target interventions in the hope of reducing later sequelae.Currently in private practice, Glendale, CaliforniaC. A. C. Schag was supported in part by Veterans Administration Health Research and Development Grant 83-002 and in part by Cares Consultants, 2210 Wilshire Blvd., Suite 359, Santa Monica, CA 90403.Address requests for Information about CARES to: CARES Consultants, 2210 Wilshire Blvd., Suite 359, Santa Monica, CA 90403, USA. Tel: (+1) 310-450-7410; Fax: (+1) 310-399-0016  相似文献   
77.
78.
Effects of posts on dentin stress distribution in pulpless teeth.   总被引:5,自引:0,他引:5  
A finite element analysis was carried out to study the roles of posts in reducing dentin stress in pulpless teeth. Two-dimensional plane strain models of the midlabiolingual section of a human maxillary central incisor were first analyzed. The results showed that the gold alloy post reduced maximal dentin stress by as much as 30%. However, the integrity of the dentin was compromised and the effects of the post were likely to be exaggerated in such models. In an effort to correct for these problems, plane stress models with side plates and axisymmetric models were analyzed. Posts were found to reduce maximal dentin stress by only 3% to 8% when the teeth were subjected to masticatory and traumatic loadings in these latter models. Although posts reduced maximal dentin stress by as much as 20% when the teeth were loaded vertically, teeth such as incisors and canines normally are not subjected to vertical loadings. Thus the reinforcement effects of posts seem to be doubtful in these teeth.  相似文献   
79.
To determine the genetic origin of the complete hydatidiform mole, 20 abnormal pregnancies were studied with restriction fragment length polymorphism with five genomic probes: EJ 6.6, beta-globin gene, 3'alpha-hypervariable region, J-Bir, and St14. In the 12 cases of molar pregnancy, pure paternal origin was proved in 11 cases, but both maternal and paternal inheritance were shown in only one case. In the cases with pure paternal origin, all of the restriction fragment length polymorphisms were homozygous, although those of the fathers were heterozygous at 15 loci. In the four cases that mimicked hydatidiform mole but were diagnosed as hydropic change of villi, both paternal and maternal inheritance were noted. In the four pregnancies with blighted ovum, both paternal and maternal inheritance were shown in three cases; and in one case with a balanced translocation between chromosomes 13 and 14, only paternal inheritance was noted. This study showed that most of the complete hydatidiform moles were caused by fertilization of an empty egg by a duplicated haploid sperm, but rare exceptions may exist.  相似文献   
80.
We present three unusual cases of molluscum contagiosum occurring in epidermal cysts. All of them are asymptomatic, elevated, oval nodules diagnosed clinically as epidermal inclusion cyst or prurigo nodularis. Histology showed true epidermal cysts containing molluscum bodies throughout the cyst wall and some type of laminated material within the cyst itself. The lesion, in all three cases developed in the pubic area of young adult men.  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