全文获取类型
收费全文 | 1499587篇 |
免费 | 120953篇 |
国内免费 | 6589篇 |
专业分类
耳鼻咽喉 | 19181篇 |
儿科学 | 48160篇 |
妇产科学 | 40078篇 |
基础医学 | 207133篇 |
口腔科学 | 41398篇 |
临床医学 | 134984篇 |
内科学 | 307757篇 |
皮肤病学 | 35998篇 |
神经病学 | 126656篇 |
特种医学 | 62641篇 |
外国民族医学 | 280篇 |
外科学 | 234341篇 |
综合类 | 32628篇 |
现状与发展 | 2篇 |
一般理论 | 488篇 |
预防医学 | 116886篇 |
眼科学 | 31923篇 |
药学 | 104628篇 |
5篇 | |
中国医学 | 2463篇 |
肿瘤学 | 79499篇 |
出版年
2018年 | 16806篇 |
2017年 | 13500篇 |
2016年 | 16364篇 |
2015年 | 17565篇 |
2014年 | 23867篇 |
2013年 | 36332篇 |
2012年 | 45039篇 |
2011年 | 48675篇 |
2010年 | 29844篇 |
2009年 | 27970篇 |
2008年 | 46143篇 |
2007年 | 48985篇 |
2006年 | 49845篇 |
2005年 | 48228篇 |
2004年 | 45873篇 |
2003年 | 45006篇 |
2002年 | 42768篇 |
2001年 | 70783篇 |
2000年 | 73774篇 |
1999年 | 60133篇 |
1998年 | 18444篇 |
1997年 | 16415篇 |
1996年 | 17117篇 |
1995年 | 17205篇 |
1994年 | 16004篇 |
1993年 | 15003篇 |
1992年 | 47953篇 |
1991年 | 46511篇 |
1990年 | 44675篇 |
1989年 | 42565篇 |
1988年 | 39366篇 |
1987年 | 38784篇 |
1986年 | 36468篇 |
1985年 | 35448篇 |
1984年 | 27165篇 |
1983年 | 22823篇 |
1982年 | 14627篇 |
1981年 | 13171篇 |
1980年 | 12404篇 |
1979年 | 24119篇 |
1978年 | 17654篇 |
1977年 | 14939篇 |
1976年 | 13680篇 |
1975年 | 14225篇 |
1974年 | 16587篇 |
1973年 | 15804篇 |
1972年 | 14513篇 |
1971年 | 13360篇 |
1970年 | 12181篇 |
1969年 | 11370篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Infantile myofibromatosis is an uncommon, benign, probably hamartomatous proliferation of myofibroblasts. Its growth is typically self-limiting but histologically it can simulate a sarcoma. A rare case of solitary infantile myofibromatosis presenting as an intraoral mass in a 10-year-old girl is reported. 相似文献
992.
Deep venous thrombosis in the surgical intensive care unit 总被引:4,自引:0,他引:4
The ICU patient population is at a high risk for the development of deep venous thrombosis leading to a potentially fatal pulmonary embolism. It is vital to appreciate this risk and apply appropriate prophylaxis. Constant vigilance is required, as deep venous thrombosis and pulmonary emboli can develop and progress despite standard prophylactic measures. In unstable patients, more aggressive prophylaxis may be warranted, including the use of inferior vena cava filters. A high index of suspicion and a low threshold for screening and diagnostic testing will allow earlier recognition and treatment of this lifethreatening condition. Treatment decisions are based on clinical suspicion, diagnostic examination results, and the potential complications of difficult treatment modalities. 相似文献
993.
CEEG mapping in drug-free schizophrenics. Differences from healthy subjects and changes induced by haloperidol treatment. 总被引:1,自引:0,他引:1
A topographic CEEG investigation was carried out in 20 drug-free, DSM-IIIR diagnosed schizophrenics and in a group of matched healthy controls. The effects of acute and chronic haloperidol treatment were then assessed in the patient group. On the baseline recording, schizophrenics showed a widespread increase in delta, theta 1 and beta 3 amplitude. Acute haloperidol administration produced a decrease in delta and an increase in slow beta amplitude. After 28 days of treatment, delta and fast beta were reduced while theta 2 and alpha 1 were increased. CEEG abnormalities in schizophrenic subjects appear, therefore, to be reduced by chronic neuroleptic treatment. 相似文献
994.
J A Webb P E Baer R J Mclaughlin R S McKelvey C D Caid 《Journal of the American Academy of Child and Adolescent Psychiatry》1991,30(4):563-568
This study examined the relationship between risk factors and initiation of alcohol use over a 15-month period among a cohort of 7th graders who were abstainers at the time of initial testing. The relationship between risk factors and alcohol use was examined using a discriminant function analysis. At the univariate level, rejection of parental authority, deviant behavior, and sensation seeking were statistically significant. The discriminant function retained only three of the risk factors: rejection of parental authority, deviant behavior, and religious commitment. Implications for school-based prevention programs are discussed, particularly the need to target primary prevention programs based upon adolescents' risk. 相似文献
995.
M R Garcia N D Ryan H Rabinovitch P Ambrosini J Twomey S Iyengar H Novacenko B Nelson J Puig-Antich 《Journal of the American Academy of Child and Adolescent Psychiatry》1991,30(3):398-406
In an effort to evaluate whether differences exist in the hypothalamic-pituitary-thyroid axis of depressed children, a thyrotropin releasing hormone (TRH) stimulation test was administered to 55 prepubertal subjects who were divided into three groups matched for age and sex: a depressed group (endogenous N = 15, nonendogenous N = 15), a psychiatric nondepressed control group (N = 16), and a normal control group (N = 9). Each subject was tested at two dosages of TRH, 2 micrograms/kg and 7 micrograms/kg. Increasing age and female sex were positively correlated with a greater thyroid stimulating hormone (TSH) response. TSH response to TRH was examined with subjects reclassified by severe suicidal ideation, severe aggression, and parental history of alcoholism. Results of this study are contrasted with the adult psychiatric literature. 相似文献
996.
Tachykinin receptor cross-talk. Immunological cross-reactivity between the external domains of the substance K and substance P receptors. 总被引:1,自引:0,他引:1
P Parnet M Mitsuhashi C W Turck B Kerdelhue D G Payan 《Brain, behavior, and immunity》1991,5(1):73-83
In the present study, we have chemically synthesized peptides which correspond to the four putative extracellular domains of the predicted substance K (SK) receptor protein and raised specific polyclonal antibodies against these peptides. These antibodies were then tested for both structural and functional recognition of epitopes on the substance P (SP) receptor on rat AR42J pancreatic cells and human IM9 lymphoblasts, which express the SP receptor, but not the SK receptor. Antibodies directed against the first, second, and fourth external domains of the predicted SK receptor recognized a 58-kDa protein on AR42J cells. This protein has a molecular weight similar to the previously demonstrated SP receptor on both AR42J cells and IM9 cells. Furthermore, antibodies against the second and fourth extracellular domains significantly inhibited specific 125I-SP binding on both AR42J and IM9 cells, and also significantly inhibited SP-induced mobilization of [Ca2+]i on AR42J cells. These data suggest that the second and fourth extracellular domains of the SK and SP receptors may share common structural motifs for ligand binding and signaling mechanism. 相似文献
997.
998.
Bone morphogenetic protein (BMP) was isolated from the bone matrix of swine and partially purified by means of differential precipitation and molecular sieve chromatography. The molecular weight of BMP estimated by SDS-gel electrophoresis was 19,000 dalton. Bioassay by implanting two milligrams of BMP fraction into thigh muscles of mice resulted in bone formation in 100% of the experimental animals.
相似文献
999.
D Burckhardt A Robertson A Hoffmann M Pfisterer 《Journal of clinical pharmacology》1991,31(11):1105-1108
A group of 34 consecutive patients with coronary artery disease (n = 29) or dilated cardiomyopathy (n = 5) (3 women, 31 men, age 38-80 yr) who had severely impaired left ventricular function (left ventricular ejection fraction less than or equal to 40%) and high-grade ventricular ectopic activity (sustained or nonsustained ventricular tachycardia or ventricular fibrillation) were treated with amiodarone (mean dose: 206 mg/d) and followed for 1-117 (mean: 49) months. In the total group, there were seven sudden deaths, five deaths due to pump failure, one non-cardiac death, and two successful heart transplantations during follow-up. Thus the annual cardiac mortality in these carefully selected and followed patients was 8, 6%, the annual cardiac event rate was 10, 1%. The cumulative cardiac survival-rate was 62% after 5 years and 41% after 10 years. In five patients, treatment was interrupted after 10 to 43 months, three of the patients were alive at follow-up and two suffered cardiac death, resulting in an annual cardiac death rate of 12% in this subgroup of treatment. Based on the results of this retrospective analysis we conclude that in patients with low left ventricular ejection fraction and nonsustained or sustained ventricular tachycardia treated with low dose amiodarone, mortality was unexpectedly low. Thus, it may be the antiarrhythmic treatment to be considered in patients with ventricular tachycardia and severe left ventricular dysfunction. 相似文献
1000.
An improved method for determining 89Sr and 90Sr in urine 总被引:1,自引:0,他引:1
A method has been developed for the rapid isolation and quantitation of 89Sr and 90Sr in urine samples. The radiostrontium is concentrated from the bulk urine sample by coprecipitation with calcium phosphate. The precipitate is then wet ashed with nitric acid, and a solution of the resulting residue in 2 M HNO3-0.5 M Al(NO3)3 is passed through an extraction chromatographic column containing a supported crown ether that preferentially retains strontium. Sorbed strontium may then be eluted from the column with either dilute HNO3 or water and counted via liquid scintillation. A new counting scheme that permits quantitation of both 89Sr and 90Sr on the same day the separation is performed is described. 相似文献