全文获取类型
收费全文 | 967篇 |
免费 | 96篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 18篇 |
妇产科学 | 8篇 |
基础医学 | 188篇 |
口腔科学 | 4篇 |
临床医学 | 120篇 |
内科学 | 254篇 |
皮肤病学 | 12篇 |
神经病学 | 48篇 |
特种医学 | 117篇 |
外科学 | 58篇 |
综合类 | 5篇 |
预防医学 | 76篇 |
眼科学 | 3篇 |
药学 | 48篇 |
中国医学 | 2篇 |
肿瘤学 | 108篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 8篇 |
2020年 | 5篇 |
2019年 | 9篇 |
2018年 | 14篇 |
2017年 | 18篇 |
2016年 | 16篇 |
2015年 | 16篇 |
2014年 | 14篇 |
2013年 | 27篇 |
2012年 | 40篇 |
2011年 | 49篇 |
2010年 | 25篇 |
2009年 | 36篇 |
2008年 | 48篇 |
2007年 | 68篇 |
2006年 | 52篇 |
2005年 | 43篇 |
2004年 | 43篇 |
2003年 | 47篇 |
2002年 | 37篇 |
2001年 | 46篇 |
2000年 | 39篇 |
1999年 | 29篇 |
1998年 | 18篇 |
1997年 | 20篇 |
1996年 | 19篇 |
1995年 | 18篇 |
1994年 | 16篇 |
1993年 | 7篇 |
1992年 | 13篇 |
1991年 | 17篇 |
1990年 | 17篇 |
1989年 | 20篇 |
1988年 | 23篇 |
1987年 | 24篇 |
1986年 | 24篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1978年 | 3篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1973年 | 3篇 |
1922年 | 2篇 |
排序方式: 共有1075条查询结果,搜索用时 93 毫秒
1.
Ohne Zusammenfassung 相似文献
2.
In a prospective, randomized, double-blind study, 49 patients underwent lumbar myelography using iotrol (24 patients) or metrizamide (25 patients). The diagnostic imaging adequacy of iotrol was comparable with that of metrizamide. After iotrol myelography, adverse reactions were fewer, less severe, and of shorter duration than were those following metrizamide myelography. Thirteen of 24 patients (54%) receiving iotrol reported some adverse reactions compared with 24 of 25 patients (96%) receiving metrizamide. Five moderate and one severe adverse reaction occurred in the group receiving iotrol. Fourteen moderate and eight severe adverse reactions occurred in the group receiving metrizamide. Thirty-eight patients underwent electroencephalography both before and after myelography (19 iotrol and 19 metrizamide). None of the EEGs obtained after iotrol myelography changed from baseline, while seven of the EEGs obtained after metrizamide myelography showed changes from baseline. Iotrol was judged superior to metrizamide as a contrast medium in this patient population. 相似文献
3.
4.
R P Heinsbroek F Van Haaren M G Feenstra E Endert N E Van de Poll 《Physiology & behavior》1991,49(6):1251-1256
Previous experiments have revealed sex-dependent effects of inescapable shock in rats. Behavior of male rats was more severely disrupted by inescapable shock than behavior of female rats. These sex differences were found after 1- and 24-hour intervals but not after a 72-hour interval. The present experiment was designed to study various physiological parameters at 1-, 4- and 24-hour intervals after inescapable footshock. The predictability of shock was manipulated by adding a compound light and tone stimulus that preceded shock presentation for one group but was not correlated with shock presentation for another group of subjects. Noradrenaline, dopamine, serotonin, and metabolites of these 3 transmitters were measured in the frontal cortex. Transient shock-induced increments in dopamine and metabolites of dopamine and serotonin were found, but the sex of the animal did not differentially affect this neurotransmitter response. In addition to neurotransmitter concentrations in the frontal cortex, levels of corticosterone were measured in plasma. The pituitary-adrenal axis was activated for a longer period in females than males after shock. The present data do not provide evidence that behavioral sex differences induced by inescapable shock are paralleled by sex differences in neurotransmitter activity. In addition, sex-dependent effects of predictability of shock on neurotransmitter activity were not detected. The relevance of the observed sex-dependent responses in the pituitary-adrenal system is discussed. 相似文献
5.
6.
Anderson RA; Evans LW; Irvine DS; McIntyre MA; Groome NP; Riley SC 《Human reproduction (Oxford, England)》1998,13(12):3319-3325
Follistatin is a binding protein for the activin and inhibin family of
hormones, regulating their biological activity. In the male reproductive
tract, the interaction of these factors is likely to be involved in the
regulation of the proliferation of several cell types. We have investigated
the presence of follistatin and activin A in seminal plasma using specific
immunoassays and have localized follistatin and activin/inhibin subunits in
the adult human testis, prostate and seminal vesicle to establish their
likely sources. High concentrations of immunoreactive follistatin were
present in seminal plasma in normal men (mean 97.9 ng/ml; 1.43 ng/ml in
peripheral plasma) and were similar in men with oligo/azoospermia and
following vasectomy. Follistatin immunoreactivity was localized to both
Leydig and Sertoli cells of the testis, and to epithelial cells of the
prostate gland and seminal vesicle, which are likely to be the predominant
sources of the hormone in seminal plasma. Activin A was also present in
seminal plasma in normal men but was undetectable following vasectomy, thus
deriving from the testis. Consistent with this finding, the betaA-subunit
was immunolocalized in Sertoli and Leydig cells but was not present in
seminal vesicle or prostate gland. The functional significance of the high
concentrations of follistatin secreted into seminal plasma by the prostate
gland and/or seminal vesicle is uncertain, but they may regulate the
biological activity of testis-derived activin A and inhibin B.
相似文献
7.
8.
van de Poll Monique L.M.; van der Hulst Dolinda A.M.; Tates Ad D.; Mulder Gerard J.; Meerman John H.N. 《Carcinogenesis》1989,10(4):717-722
N-Hydroxy-Z-acetylaminofluorene (N-OH-AAF) was administeredi.p. to male Wistar rats 17 h after partial hepatectomy. Hepatocyteswere analyzed for the presence of micronuclei 7 h, 1, 2, 3 and4 days after injection. N-OH-AAF treatment resulted in a highfrequency of micronucleated hepatocytes at days 3 and 4 (19.5and 19.6 respectively). The frequency of micronucleated hepatocyteswas not increased above control values when hepatocytes wereisolated as early as 7 h, 1 or 2 days after injection. Pretreatmentwith the sulfotransferase inhibitor pentachlorophenol (PCP)45 min before injection of N-OH-AAF almost completely preventedthe formation of micronuclei by N-OH-AAF. Parallel biochemicalstudies indicated that inhibition of sulfation of N-OH-AAF byPCP pretreatment prevented the formation of the N-acetylatedDNA adducts iV-deoxyguanosin-8-yl-AAF and 3-deoxyguanosin-N2-yl-AAFby {small tilde}85%. Total adduct formation to DNA was, however,not lowered because of an increase in the formation of the deacetylatedadduct, N-deoxy-guanosin-8-yl-AAF. The lower frequency of micronucleatedhepatocytes observed in the group pretreated with PCP, did notresult from less proliferative activity in this group as comparedto the group treated with N-OH-AAF alone. Therefore, the decreasein the formation of micronuclei indicates that PCP preventsthe clastogenic damage caused by N-OH-AAF. It is concluded thatthe clastogenicity of N-OH-AAF in rat liver is related to theformation of N-acetylated DNA adducts (i.e. N-deoxyguanosin-8-yl-AAFand/or 3-deoxy-guanosin-N2-yl-AAF) and is not related to theformation of the deacetylated DNA adduct N-deoxyguanosin-8-yl-AF. 相似文献
9.
10.
Olszyna DP Prins JM Dekkers PE De Jonge E Speelman P Van Deventer SJ Van Der Poll T 《Journal of clinical immunology》1999,19(6):399-405
Chemokines are a superfamily of small chemotactic proteins. While increased levels of interleukin-8 have been measured in serum and urine during urinary tract infection, little is known about other chemokines in this condition. Monocyte chemoattractant protein (MCP)–1, macrophage inflammatory protein (MIP)–1, MIP-1 and interferon- inducible protein (IP)–10 were measured in 30 patients with culture-proven urosepsis during a 3-day follow-up and in 11 healthy humans after intravenous injection of endotoxin (4 ng/kg). Urine and serum levels of MCP-1, MIP-1, and IP-10, but not of MIP-1, were elevated in patients on admission, and decreased after initiation of antibiotic treatment. Endotoxin administration to healthy subjects induced increases in plasma and urine concentrations of all four chemokines. These data indicate that clinical and experimental gram-negative infection in humans is associated with enhanced production of chemokines that act mainly on mononuclear cells and that these chemokines are at least in part locally produced. 相似文献