全文获取类型
收费全文 | 23210篇 |
免费 | 1030篇 |
国内免费 | 141篇 |
专业分类
耳鼻咽喉 | 230篇 |
儿科学 | 420篇 |
妇产科学 | 465篇 |
基础医学 | 2967篇 |
口腔科学 | 474篇 |
临床医学 | 1460篇 |
内科学 | 5540篇 |
皮肤病学 | 322篇 |
神经病学 | 2245篇 |
特种医学 | 955篇 |
外科学 | 3921篇 |
综合类 | 85篇 |
一般理论 | 5篇 |
预防医学 | 736篇 |
眼科学 | 492篇 |
药学 | 1346篇 |
中国医学 | 23篇 |
肿瘤学 | 2695篇 |
出版年
2023年 | 110篇 |
2022年 | 284篇 |
2021年 | 497篇 |
2020年 | 273篇 |
2019年 | 351篇 |
2018年 | 437篇 |
2017年 | 340篇 |
2016年 | 393篇 |
2015年 | 440篇 |
2014年 | 563篇 |
2013年 | 743篇 |
2012年 | 1126篇 |
2011年 | 1140篇 |
2010年 | 632篇 |
2009年 | 579篇 |
2008年 | 898篇 |
2007年 | 1039篇 |
2006年 | 991篇 |
2005年 | 908篇 |
2004年 | 901篇 |
2003年 | 878篇 |
2002年 | 961篇 |
2001年 | 690篇 |
2000年 | 744篇 |
1999年 | 689篇 |
1998年 | 272篇 |
1997年 | 215篇 |
1996年 | 204篇 |
1995年 | 199篇 |
1994年 | 196篇 |
1993年 | 185篇 |
1992年 | 637篇 |
1991年 | 560篇 |
1990年 | 554篇 |
1989年 | 560篇 |
1988年 | 504篇 |
1987年 | 487篇 |
1986年 | 439篇 |
1985年 | 452篇 |
1984年 | 252篇 |
1983年 | 212篇 |
1979年 | 232篇 |
1978年 | 129篇 |
1977年 | 100篇 |
1975年 | 98篇 |
1974年 | 99篇 |
1973年 | 98篇 |
1970年 | 103篇 |
1969年 | 123篇 |
1968年 | 99篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
S Fujino S Inoue N Yamashita A Mori 《The Journal of thoracic and cardiovascular surgery》1992,104(4):1067-1074
The effects of direct revascularization of the bronchial artery after bronchoplasty were estimated by laser Doppler velocimetry and india ink injection in dogs. Bronchoplastic surgery at the right main bronchus was performed in all dogs, and the bronchial artery was reconstructed using the internal thoracic artery in the reconstruction group. The mucosal blood flow was measured at the distal side of the anastomosis. India ink was injected into the aorta in the nonreconstruction group and into the internal thoracic artery in the reconstruction group. The peripheral blood flow had diminished immediately after surgeries to 59% of the baseline value and took 14 days to recover to the baseline value in the nonreconstruction group. However, in the reconstruction group, the blood flow recovered at once to 78% of the baseline value and had returned to that value in 5 days. Statistically significant differences were noted between the groups from just after operation to day 7. India ink data confirmed these findings. In the nonreconstruction group, no ink was observed in the peripheral bronchial vessels on day 3; it was noted in part of the vessels on day 7 and in most on day 14. On the other hand, a relatively large number of vessels were stained just after operation in the reconstruction group. Thus reconstruction of the bronchial artery by means of the anastomosis with the internal thoracic artery can be said to be a useful and effective method for preventing airway ischemia. 相似文献
72.
Intraperitoneal injection of free valproic acid (VPA) suppressed amygdaloid-kindled seizure 1 h after injection in rats, but had no effect at 24 h. VPA entrapped in positively charged liposomes showed a prolonged anticonvulsant effect lasting for 2 days, while the effect evaluated at 1 h was not different from that with free VPA. VPA entrapped in negatively charged liposomes exerted a significantly stronger effect at 1 h than did free VPA, while it had no significant effect at 24 h. These results suggest that surface charges on liposomes play an important role in modifying the anticonvulsant effect of VPA. 相似文献
73.
74.
T Hayashi M Ozaki I Mori M Saito T Itoh H Yamamoto 《International journal of experimental pathology》1992,73(2):173-181
The lactic dehydrogenase (LDH) level in plasma and the clearance of LDH in C.B-17 scid (severe combined immunodeficiency; SCID) mice were compared with those in C.B-17 or BALB/cCrSlc mice with or without lactic dehydrogenase virus (LDV) infection. The resting enzyme level in SCID mice showed little difference from that in C.B-17 or BALB/cCrSlc mice. The degree of increased plasma LDH level in SCID mice was lower than that in C.B-17 and BALB/cCrSlc mice after LDV infection. To assess the mechanisms of decrease in LDH elevation in SCID mice infected with LDV, virus replication was compared in SCID and BALB/cCrSlc mice. The infectivity titre of plasma in SCID mice was higher (more than 10 times) than that in BALB/cCrSlc mice. Moreover, the percentage of virus antigen positive Kupffer cells was higher in SCID mice than that in BALB/cCrSlc mice. The level of endogenous LDH release as a result of carbon tetrachloride treatment was similar in the SCID and BALB/cCrSlc mice. The clearance rate of endogenous LDH was greater in SCID mice than in BALB/cCrSlc mice with or without LDV infection. The rate of clearance of intravenously injected porcine LDH-5, but not porcine LDH-1, was enhanced in SCID mice as compared with that in BALB/cCrSlc mice. Furthermore, carbon clearance was higher in SCID mice than that in BALB/cCrSlc mice. These results suggest that the smaller increase of plasma LDH after infection might be due, at least in part, to the enhanced LDH-5 clearance function by macrophages in SCID mice. 相似文献
75.
Sugie Shigeyuki; Yoshimi Naoki; Tanaka Takuji; Mori Hideki; Williams Gary M. 《Carcinogenesis》1994,15(1):95-98
The nuclear pore density and area were measured on freeze-fracturednuclei of ACI/N rat liver altered foci, adenomas and carcinomasinduced by 2-acetylaminofluorene, and compared with those ofnormal hepatocytes. The pore density of nuclei from these preneoplasticand neoplastic lesions was significantly higher than that ofhepatocytes, but there was no difference between lesions. Thearea of nuclear pores of the focus cells did not differ fromnormal hepatocytes, whereas the areas of pores of adenoma andcarcinoma cells were increased. Moreover, the nuclear pore areaof carcinomas was significantly greater than that of adenomas.These results suggest that some changes may occur in nuclearpores in the progress of tumorigenesis. 相似文献
76.
77.
A neuromotor screening tool, The Chandler Movement Assessment of Infants Screening Test (CMAI-ST), was selected to teach nurses who care for premature infants about neuromotor development. After training with the CMAI-ST, the nurses were more adept at recognizing major components of neuromotor development. 相似文献
78.
In a model of dyskinesia induced by the administration of iminodipropionitrile (IDPN) in the rat, we evaluated the effects of ceruletide, an analogue of cholecystokinin, on behavioral abnormalities and monoaminergic neuronal function. Vertical head twitching in the IDPN-treated animals was inhibited for over 5 h following a single subcutaneous dose of 160 micrograms/kg ceruletide. In animals dosed daily for 2 or 3 days, the number of head twitches at 24 h after the last dose was about one-third of the number before treatment. After repeated daily doses of ceruletide for 6 days, the number of head twitches was reduced to low levels and remained significantly below pretreatment levels until the 4th posttreatment day. These results indicate that the inhibition of dyskinesia by ceruletide was long-lasting. Assays of monoaminergic neurotransmitters and their metabolites in various brain regions indicate that an imbalance between dopaminergic and serotonergic neuronal systems plays a major role in the pathogenesis of the IDPN-induced dyskinesia, i.e. the ratio of (DOPAC+HVA)/5-HIAA was significantly greater in the striatum but significantly smaller in the hippocampus of the IDPN-treated vs normal animals. This initially abnormal ratio of (DOPAC+HVA)/5-HIAA in the striatum and hippocampus of IDPN-treated animals returned to normal following treatment with ceruletide, corresponding with the reduction of the head twitching. The alterations in monoaminergic neuronal function induced by repeated administration of ceruletide persisted for at least 3 days, even though its plasma half-life is several minutes. Ceruletide also exerted a marked effect on monoaminergic neuronal function in the IDPN-treated rats, in contrast to only a slight effect in normal animals.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
79.
Toshiharu Mori Nobukazu Okimoto Akinori Sakai Yuichi Okazaki Nariaki Nakura Takuya Notomi Toshitaka Nakamura 《Journal of bone and mineral research》2003,18(11):2002-2009
To investigate the relationship between the effects of bone turnover and bone marrow cell development in bone cells, we developed a mouse voluntary climbing exercise model. Climbing exercise increased bone volume and transient osteogenic potential of bone marrow. This model would be suitable for investigating the mechanistic roles of mechanical loading. INTRODUCTION: The relationship between bone mass gain and local bone formation and resorption in mechanically loaded bone is not well understood. MATERIALS AND METHODS: Sixty-five C57BL/6J mice, 8 weeks of age, were assigned to five groups: a baseline control and two groups each of ground control and climbing exercise mice for 2 and 4 weeks. Mice were housed in a 100-cm tower and had to climb toward a bottle placed at the top to drink water. RESULTS: Compared with the ground control, bone mineral density of the left femur increased in the climbing mice at 4 weeks. At 2 and 4 weeks, bone formation rate (BFR/BS) of periosteal surface, the cross-sectional area, and moment of inertia were increased in the climbing mice, whereas BFR/BS and eroded surface (ES/BS) of endosteal surface did not differ. The trabecular bone volume (BV/TV) of the proximal tibia increased in climbing mice, and osteoclast surface (Oc.S/BS) and osteoclast number decreased at 2 weeks. At 4 weeks, there were increases in BV/TV and parameters of bone formation, including mineralized surface, mineral apposition rate, and bone formation rate. In marrow cell cultures from the tibia, the number of alkaline phosphatase+ colony forming units-fibroblastic and the area of mineralized nodule formation in climbing mice were increased, and the number of osteoclast-like TRACP+ multinucleated cells was lower at 2 weeks. At 4 weeks, these parameters recovered to the levels of the ground controls. CONCLUSION: Our results indicate that climbing increased trabecular bone volume and reduced bone resorption, with a subsequent increase in bone formation. Intermittent climbing downregulates marrow osteoclastogenic cells and upregulates osteogenic cells initially, but further exercise seemed to desensitize them. Cortical envelopes were enlarged earlier, but the response seems to differ from trabecular bone. 相似文献
80.
M Di Giacomo P Leggeri G Papeo D Pirillo G Traverso 《Il Farmaco; edizione pratica》1992,47(3):379-385
Following our research on the arachidonic acid metabolites and their derivatives with potential biological activity, we describe the synthesis of the (+-)-8,12-trans-(5Z, 14Z)-9-oxo-prosta-5,14-dienoic acid, a 11-deoxyprostanoid correlated to the class of Preclavulones, one of the unusual families of marine eicosanoids from the coral Clavularia Viridis with considerable biological interest. 相似文献