全文获取类型
收费全文 | 741732篇 |
免费 | 50721篇 |
国内免费 | 1437篇 |
专业分类
耳鼻咽喉 | 9612篇 |
儿科学 | 25556篇 |
妇产科学 | 18226篇 |
基础医学 | 114615篇 |
口腔科学 | 20959篇 |
临床医学 | 66390篇 |
内科学 | 140743篇 |
皮肤病学 | 17162篇 |
神经病学 | 51572篇 |
特种医学 | 26788篇 |
外国民族医学 | 76篇 |
外科学 | 109903篇 |
综合类 | 15958篇 |
现状与发展 | 2篇 |
一般理论 | 175篇 |
预防医学 | 53179篇 |
眼科学 | 17644篇 |
药学 | 57600篇 |
4篇 | |
中国医学 | 2672篇 |
肿瘤学 | 45054篇 |
出版年
2021年 | 6964篇 |
2019年 | 6354篇 |
2018年 | 9151篇 |
2017年 | 7055篇 |
2016年 | 8064篇 |
2015年 | 8768篇 |
2014年 | 12077篇 |
2013年 | 17438篇 |
2012年 | 23383篇 |
2011年 | 24326篇 |
2010年 | 14392篇 |
2009年 | 13247篇 |
2008年 | 21834篇 |
2007年 | 23355篇 |
2006年 | 23591篇 |
2005年 | 21939篇 |
2004年 | 21386篇 |
2003年 | 20100篇 |
2002年 | 19455篇 |
2001年 | 36968篇 |
2000年 | 37437篇 |
1999年 | 30846篇 |
1998年 | 8103篇 |
1997年 | 6845篇 |
1996年 | 7154篇 |
1995年 | 6793篇 |
1994年 | 6220篇 |
1992年 | 23235篇 |
1991年 | 23198篇 |
1990年 | 22594篇 |
1989年 | 22330篇 |
1988年 | 20258篇 |
1987年 | 19601篇 |
1986年 | 18652篇 |
1985年 | 17480篇 |
1984年 | 12841篇 |
1983年 | 10840篇 |
1982年 | 5982篇 |
1979年 | 11605篇 |
1978年 | 8189篇 |
1977年 | 6901篇 |
1976年 | 6646篇 |
1975年 | 7308篇 |
1974年 | 8546篇 |
1973年 | 8188篇 |
1972年 | 7696篇 |
1971年 | 7181篇 |
1970年 | 6919篇 |
1969年 | 6324篇 |
1968年 | 5815篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Confounders contributing to the reported associations of coffee or caffeine with disease 总被引:2,自引:0,他引:2
G B Schreiber M Robins C E Maffeo M N Masters A P Bond D Morganstein 《Preventive medicine》1988,17(3):295-309
The role of caffeine or coffee in causing or promoting the incidence of serious disease is equivocal. Two design factors may account for the discrepancies in reported findings on the effects of coffee drinking: (a) imprecision of measurement and (b) confounding variables. A study of 2,714 white U.S. adults disclosed that, of 32 risk factors analyzed by linear and logistic regression, only sex and cigarette smoking were found to be important potential confounders of caffeine and coffee intake. Partial R2 values of the other 30 risk factors were relatively small and were inconsistent for each sex. It is unlikely that any of these factors could explain any of the reported associations between caffeine or coffee consumption and certain diseases. However, certain weak associations with caffeine or coffee intake should be included in the study design when they are known to be risk factors of a disease under investigation. These factors for men are dietary fat intake, vitamin C intake, and body mass index; and for women are vitamin use, alcohol intake, stress, and perceived health status. 相似文献
53.
54.
N V Kornilov B M Rachkov V I Kulik V M Kustov 《Vestnik khirurgii imeni I. I. Grekova》1990,145(8):62-66
A retrospective analysis of results of treatment of 104 patients with fractures of long tubular bones associated with injuries of peripheral nerves has shown complex therapy to be necessary. Main components of this treatment were biogenic stimulators, vitamin B12, spasmolytic and dehydration drugs in combination with electrophoresis with potassium iodide and thermal procedures. Rapid disturbance of conductivity of nerve trunks after trauma should be followed by revision of the given segment of the extremity in order to remove hematoma and make reposition of displaced fragments of the bone, which can provide recovery of the disturbed function of the nerve. 相似文献
55.
D A Evans B N Hamid E M Hoare 《Journal of the Royal College of Surgeons of Edinburgh》1990,35(1):33-35
Thirteen cases of primary appendicular adenocarcinoma are reported. This rare tumour usually presents as acute appendicitis. The correct diagnosis is rarely entertained before or during surgery. The main treatment choice lies between appendicectomy alone and appendicectomy followed by right hemicolectomy. There are anatomical reasons for advising the latter and survival figures from the literature tend to support this preference. The cases reported here indicate that in the period 1972-1984, in the North West Region, there was a slight preference for appendicectomy alone. The additional procedure of right hemicolectomy did not confer any clear-cut survival advantage. 相似文献
56.
57.
Summary A case of bilateral congenital pseudarthrosis of the clavicle in a baby boy is described. The patient is fully asymptomatic, and no functional impairment is present. This is probably only the seventh case described of this rare congenital anomaly. 相似文献
58.
T Abumiya I Sayama K Asakura H Hadeishi M Mizuno A Suzuki N Yasui F Shishido K Uemura 《No shinkei geka. Neurological surgery》1990,18(9):837-844
Regional effects of craniotomy on cerebral circulation and metabolism, such as regional cerebral blood flow (rCBF), regional cerebral oxygen consumption (rCMRO2), regional oxygen extraction fraction (rOEF), and regional cerebral blood volume (rCBV) were examined by a PET (positron emission tomography) study concerning surgery that was performed on unruptured aneurysm patients. Eight patients with intracranial un-ruptured aneurysms were studied pre- and post-operatively by the 15O labelled-gas steady-state method, using HEADTOME-III. All patients underwent aneurysmal surgery performed by the transsylvian approach. There was a significant increase in the mean OEF values taken from the whole-brains of 8 patients, but there was not a significant change in CBF, CMRO2 or CBV. The increase in OEF was caused by decrease of O2 content, which was caused by post-operative decrease in the Hb value. So, this OEF increase was not the direct effect of craniotomy. In 2 patients, the rCBF and rCMRO2, in the fronto-temporal region (where craniotomy was performed) increased post-operatively. This regional effect suggests transient reactive hyperemia following compressive ischemia during the operative procedure, and metabolic demands for recovery of brain function. In 2 other patients, who had relatively low rCBFs during the pre-operative study, rCBF and rCMRO2 in the bi-frontal region had decreased more at the post-operative study. This change appears to have been caused by removal of cerebrospinal fluid and depression of the frontal lobe. From this study, it becomes evident that the regional effect of craniotomy on cerebral circulation and metabolism is not so great, when adequate microsurgical techniques are used. 相似文献
59.
60.
In the present study, we examined the effect of CsA on the in vitro production of Ig and on the in vitro production of molecules known to have B-cell growth and differentiation activities, such as IL-6 and sCD23. For the purpose of this study, we developed an experimental In vitro system closely resembling an In vivo model of ongoing B-cell activation. Pre-activated B cells proliferated and produced IgM optimally when they were re-cultured in the presence of IL-2/IL-6. CsA down-regulated the IL-2/IL-6-induced proliferative responses of pre activated B cells by at least 50%., but it up-regulated IgM production in the same experiments. This up regulating effect was not cytokine-related since it was also seen when cells were re-cultured in the absence of any cytokines. Optimal release of sCD23 was observed when SAC-pre-activated B cells were re cultured in the presence of IL-4 or IL-4 plus IL-2 and CsA up-regulated significantly the release of this molecule in these cultures. Finally, CsA was shown to inhibit PHA-induced cell proliferation of PBMC and to up-rcgulate IL-6 production in the same cultures. We conclude that CsA can amplify in vitro both the production of Ig and the release of sCD23 by pre activated B cells. This finding, in combination with the CsA-induced up-regulation of lectin-induced IL-6 production, may have clinical implications in disease states with an ongoing immune activation, where prolonged administration of CsA might be anticipated. 相似文献