全文获取类型
收费全文 | 1988篇 |
免费 | 93篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 43篇 |
妇产科学 | 45篇 |
基础医学 | 222篇 |
口腔科学 | 25篇 |
临床医学 | 117篇 |
内科学 | 609篇 |
皮肤病学 | 26篇 |
神经病学 | 99篇 |
特种医学 | 65篇 |
外科学 | 365篇 |
综合类 | 11篇 |
预防医学 | 42篇 |
眼科学 | 76篇 |
药学 | 87篇 |
中国医学 | 1篇 |
肿瘤学 | 261篇 |
出版年
2023年 | 17篇 |
2022年 | 28篇 |
2021年 | 59篇 |
2020年 | 36篇 |
2019年 | 46篇 |
2018年 | 65篇 |
2017年 | 45篇 |
2016年 | 41篇 |
2015年 | 49篇 |
2014年 | 63篇 |
2013年 | 60篇 |
2012年 | 107篇 |
2011年 | 134篇 |
2010年 | 53篇 |
2009年 | 42篇 |
2008年 | 91篇 |
2007年 | 104篇 |
2006年 | 110篇 |
2005年 | 131篇 |
2004年 | 119篇 |
2003年 | 119篇 |
2002年 | 114篇 |
2001年 | 40篇 |
2000年 | 36篇 |
1999年 | 37篇 |
1998年 | 30篇 |
1997年 | 33篇 |
1996年 | 32篇 |
1995年 | 21篇 |
1994年 | 32篇 |
1993年 | 10篇 |
1992年 | 17篇 |
1991年 | 24篇 |
1990年 | 19篇 |
1989年 | 16篇 |
1988年 | 22篇 |
1987年 | 22篇 |
1986年 | 12篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 2篇 |
1973年 | 2篇 |
1969年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有2100条查询结果,搜索用时 15 毫秒
1.
2.
K Tamazawa H Arima T Kojima Y Isomura M Okada S Fujita T Furuya T Takenaka O Inagaki M Terai 《Journal of medicinal chemistry》1986,29(12):2504-2511
Four enantiomers (3a-d) of the title compound, YM-09730 (3), were synthesized by the reaction of (-)- or (+)-5-(methoxycarbonyl)-2, 6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3-carboxylic acid (1a or 1b) with (S)- or (R)-1-benzyl-3-pyrrolidinol (2a or 2b). [3H]Nitrendipine binding affinity and coronary vasodilating activity of these compounds were evaluated. The absolute configuration of the most potent enantiomer (3a) with the longest duration was unequivocally determined to be (S)-1,4-dihydropyridine-C4 and (S)-pyrrolidine-C3 (S,S) by X-ray crystallographic study on 3a X HBr as well as 3a X HCl. The configuration of 1a corresponds to R, and the other enantiomers of 3 were respectively determined by chemical correlation. The potency order of the four enantiomers was (S,S)-3a greater than (S,R)-3b greater than (R,R)-3d greater than (R,S)-3c. Latent chiral characters of nifedipine derivatives with the identical ester groups were assigned by comparison of their puckering modes of 1,4-dihydropyridine (DHP) rings with those found in 3a X HCl or 3a X HBr. On the basis of the assignment, it has been revealed that the (S)-DHP nifedipine derivatives possess the synperiplanar carbonyl group at C5. The conformational restriction may be a factor causing stereoselectivity of antagonism. 相似文献
3.
K. Arima Minako Nakamura Nobuhiko Sunohara Masafumi Ogawa Midori Anno Yoko Izumiyama Shigeo Hirai Kazuhiko Ikeda 《Acta neuropathologica》1997,93(6):558-566
Coiled bodies and interfascicular threads are conspicuous white matter abnormalities of brains of patients with progressive
supranuclear palsy (PSP). Both structures are argyrophilic and immunoreactive for the microtubule-binding protein tau. This
report concerns the ultrastructural localization of interfascicular threads and their relationship to coiled bodies in five
PSP patients. We showed for the first time that abnormal tubules with a 13- to 15-nm diameter and fuzzy outer contours were
the common structures of coiled bodies in the oligodendroglial perikarya and of interfascicular threads. Moreover, the tubules
were immunolabeled by anti-tau antibodies. The abnormal tau-positive tubules of interfascicular threads were located in the
inner loop of the myelin sheath. Our study further indicated that the thread-like structures in the white matter comprised,
at least in part, oligodendroglial processes, and that they were also present in gray matter. We consider that the formation
of coiled bodies in the perikarya and of interfascicular threads represents a common cytoskeletal abnormality of the oligodendroglia
of PSP patients. Moreover, even though the white matter alterations of PSP resemble those of corticobasal degeneration, there
are certain ultrastructural differences in the abnormal oligodendroglial tubules of the two diseases.
Received: 4 October 1996 / Accepted: 6 December 1996 相似文献
4.
Hisashi Sugiyama Toshie Kadono Minako Hoshiai Tetsushi Tan Keiichi Koizumi Hajime Sakamoto Simpei Nakazawa 《Catheterization and cardiovascular interventions》2004,63(3):346-350
We report here the first described case of utilizing gadolinium-based contrast material as the contrast agent during a catheter intervention treatment for pulmonary artery stenosis. The patient, a male infant with complex heart disease associated with a right isomerism, had a history of severe allergic reaction to iodine-containing contrast agents. A combination of digital subtraction angiography and a gadolinium contrast agent, however, provided us with good-quality images both before and after balloon angioplasty without any associated complications. This method should therefore be considered as an alternative angiographic procedure in children with a high risk of iodine-related allergic complications. 相似文献
5.
Mitsuru Masaki Tadashi Kuroda Naoki Hosen Hisao Hirota Kazuo Terai Yuichi Oshima Yoshikazu Nakaoka Shoko Sugiyama Ryusuke Kimura Satoshi Yoshihara Manabu Kawakami Norishige Iizuka Yasuhiko Tomita Hiroyasu Ogawa Ichiro Kawase Keiko Yamauchi-Takihara 《Journal of the American Society of Echocardiography》2004,17(4):397-398
A 57-year-old man with a history of renal cell carcinoma presented with presyncope. He underwent nephrectomy years earlier followed by HLA-matched allogeneic peripheral-blood stem-cell transplantation. Echocardiographic investigation revealed a solitary right ventricle mass without contiguous vena caval or right atrial involvement. The mass was pathologically confirmed to be metastatic carcinoma in the right ventricular cavity. This case highlights the need to consider an underlying neoplastic syndrome in patients presenting isolated right ventricle mass by echocardiography. 相似文献
6.
7.
A CASE OF METASTATIC YOLK SAC TUMOR OF TESTIS IN A CHILD 总被引:1,自引:0,他引:1
Akito Terai Satoshi Ishitoya Takayuki Hashimura Hideo Takeuchi Osamu Yoshida 《International journal of urology》1995,2(2):135-138
We report a case of testicular yolk sac tumor in a child aged 3 years and 6 months with multiple bulky metastases to lung and retroperitoneum (stage 11182). After three courses of chemotherapy with a PV 8 regimen (cisplatin, vinblastine and bleomycin). complete and partial responses were obtained for lung and retroperitoneal lymph node metastases, respectively. The patient was followed-up closely. However, on the basis of a re-elevated alpha-letoprotein (AFP) after 4 months' follow-up, he was treated with three courses of salvage chemotherapy with a modified VAB-6 regimen (cyclophosphamide. etoposide. actinomycin D, bleomycin and cisplatin), lollowed by retroperitoneal lymph node dissection. Histologically, only necrotic tissue was found. There is no evidence of recurrence 24 months after lymphadenectomy. There is very little information in the literature on the appropriate management of postchemotherapy residual mass in pediatric testicular tumors. 相似文献
8.
The effects of intraperitoneal
and
methyl ester, specific inhibitors of nitric oxide (NO) synthase, were examined on the pentylenetetrazol (PTZ)-induced seizures in rats. The incidence and latency for the onset of myoclonic jerks, clonic seizures, and tonic generalized extension were observed as specific parameters among PTZ-induced seizures. Both drugs preferentially suppressed the tonic generalized extension and prolonged the latency for the onset of each parameter, suggesting NO has a significant effect on the PTZ-induced seizure. 相似文献
9.
Tetsushi Furukawa Tei-ichi Yamane Tomoko Terai Yoshifumi Katayama Masayasu Hiraoka 《Pflügers Archiv : European journal of physiology》1996,431(4):504-512
The role of the cytoskeleton in the rundown and reactivation of adenosine triphosphate (ATP) sensitive K+ channels (KATP channels) was examined by perturbing selectively the intracellular surface of inside-out membrane patches excised from guinea-pig ventricular myocytes. Actin filament-depolymerizing agents (cytochalasins and desoxyribonuclease I) accelerated channel rundown, while actin filament stabilizer (phalloidin) or phosphatidylinositol biphosphate (PIP2; inhibitor of F-actin-severing proteins) inhibited spontaneous and/or Ca2+-induced rundown. When rundown was induced by cytochalasin D or by long exposure to high Ca2+, channel activity could not be restored by exposure to MgATP, but application of F-actin with MgATP could reinstitute channel activity. The processes of rundown and reactivation of cardiac KATP channels may thus be influenced by the assembly and disassembly of the actin cytoskeletal network, which provides a novel regulatory mechanism of this channel. 相似文献
10.
Cloning and nucleotide sequencing of Vero toxin 2 variant genes from Escherichia coli O91:H21 isolated from a patient with the hemolytic uremic syndrome 总被引:14,自引:0,他引:14
Cellular DNA extracted from Escherichia coli strain B2F1 (O91:H21) was found to contain two separate DNA sequences that hybridized with a Vero toxin 2 (VT2)-specific gene probe under stringent conditions. These two sequences were cloned and both were shown to encode a variant of Vero toxin 2 (VT2vh). The nucleotide sequences of the operons encoding VT2vh, designated as vtx2ha and vtx2hb, were determined. The two operons were nearly identical (99% overall DNA homology) and both encoded A subunits of 319 amino acid residues and B subunits of 89 amino acid residues, the A and B subunit genes being separated by a stretch of 14 bp. The A and B subunit genes of the vtx2ha operon exhibited 98.6% and 95.5% DNA homology, respectively, with those of the slt-II operon encoding Shiga-like toxin II (or VT2) cloned from a strain from a patient with hemorrhagic colitis, while the A and B subunit genes of the vtx2ha operon showed 94.5% and 82.8% DNA homology, respectively, with those of the slt-IIv operon encoding a SLT-II variant cloned from a strain isolated from a pig with edema disease. The nucleotide sequences of the presumed promoters and presumptive ribosome binding sites in the vtx2ha, vtx2hb, and slt-II, and slt-IIv operons were identical. These results indicate that nucleotide sequences encoding a family of VT2-related toxins are present in various strains of E. coli and that the sequences of the genes for A subunits are better conserved than those of the B subunit genes. 相似文献