全文获取类型
收费全文 | 8311篇 |
免费 | 359篇 |
国内免费 | 81篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 276篇 |
妇产科学 | 49篇 |
基础医学 | 1122篇 |
口腔科学 | 129篇 |
临床医学 | 416篇 |
内科学 | 2369篇 |
皮肤病学 | 338篇 |
神经病学 | 528篇 |
特种医学 | 495篇 |
外科学 | 1353篇 |
综合类 | 35篇 |
预防医学 | 221篇 |
眼科学 | 167篇 |
药学 | 436篇 |
中国医学 | 16篇 |
肿瘤学 | 743篇 |
出版年
2023年 | 62篇 |
2022年 | 124篇 |
2021年 | 189篇 |
2020年 | 96篇 |
2019年 | 142篇 |
2018年 | 178篇 |
2017年 | 145篇 |
2016年 | 160篇 |
2015年 | 184篇 |
2014年 | 240篇 |
2013年 | 305篇 |
2012年 | 485篇 |
2011年 | 511篇 |
2010年 | 319篇 |
2009年 | 274篇 |
2008年 | 464篇 |
2007年 | 520篇 |
2006年 | 474篇 |
2005年 | 556篇 |
2004年 | 559篇 |
2003年 | 567篇 |
2002年 | 578篇 |
2001年 | 92篇 |
2000年 | 90篇 |
1999年 | 121篇 |
1998年 | 135篇 |
1997年 | 99篇 |
1996年 | 118篇 |
1995年 | 88篇 |
1994年 | 84篇 |
1993年 | 64篇 |
1992年 | 79篇 |
1991年 | 61篇 |
1990年 | 59篇 |
1989年 | 51篇 |
1988年 | 44篇 |
1987年 | 42篇 |
1986年 | 34篇 |
1985年 | 35篇 |
1984年 | 40篇 |
1983年 | 36篇 |
1982年 | 21篇 |
1981年 | 35篇 |
1980年 | 27篇 |
1979年 | 23篇 |
1978年 | 22篇 |
1977年 | 19篇 |
1974年 | 12篇 |
1970年 | 8篇 |
1967年 | 9篇 |
排序方式: 共有8751条查询结果,搜索用时 125 毫秒
31.
Although Mutoh et al. have found intercalated ducts in the pancreatic islets of avians, including the chicken, moorhen (Gallinula chloorpus), and Japanese quail (Coturnix coturnix japonica), and even demonstrated the functions of intercalated duct cells in pancreatic islets, to our knowledge, there have been only a few reports on the relationship between intercalated ducts and islets in mammalia. Accordingly, in this study, we investigated whether intercalated ducts are morphologically related to the islets of cattle, by using S-100 protein as a ductal cell marker for immunocytochemistry and examining the ultrastructure of intercalated ducts and islets electron-microscopically. The results revealed intercalated ducts that reacted positively for S-100 protein within and near islets, with approximately 12% of the islets having intercalated ducts in the vicinity and approximately 1.5% containing intercalated ducts within them. Ultrastructurally, intercalated ducts were also seem to be closely related to the islets. In conclusion, the results of the present study indicate that a close relationship exists between intercalated ducts and islets. 相似文献
32.
Matsuyama A Yonemitsu N Hayashida S Watanabe K Sugihara H Inokuchi A 《Pathology international》2003,53(1):46-50
Osteosarcoma is one of the neoplasms that may occur following exposure to radiation. A case of osteosarcoma arising in the craniofacial bone with a short latency period of 3 years after radiotherapy for maxillary squamous cell carcinoma is described. A 64-year-old-man underwent right partial maxillectomy and chemoradiotherapy due to squamous cell carcinoma of his right maxillary sinus. Histologically, the tumor was composed of moderately differentiated squamous cell carcinoma with a component of spindle cell carcinoma. Three years later, osteosarcoma developed in the craniofacial bone within the irradiation field of the first tumor. Detailed histological examination demonstrated that there was no component of osteosarcoma in the first tumor or squamous cell carcinoma in the second tumor. Radiation-induced osteosarcoma usually occurs after a long latency period of more than 10 years after the radiotherapy. In this case, osteosarcoma was possibly a radiation-induced osteosarcoma with a short latency period of 3 years. 相似文献
33.
T. Takaki 《Medical & biological engineering & computing》1988,26(4):397-403
The paper considers the limiting factors in EEG enhancement in the presence of electrosurgery interference and presents a
design for a useful fibre-optic EEG monitoring instrument which is free from such problems as electrical shock (micro and
macroshock), patient burns and susceptibility to electrosurgery interference associated with conventional EEG monitors. 相似文献
34.
Functional role of lumbar sympathetic nerves and supraspinal mechanism in the defecation reflex of the cat 总被引:2,自引:0,他引:2
The role of the lumbar sympathetic nerves and supraspinal mechanism in the defecation reflex was investigated in 30 adult cats and 6 kittens. One or two propulsive contractions, whose mean pressure evoked was more than about 90 cmH2O (adult cats) and 50 cmH2O (kittens), were induced in the rectum of all animals by rectal distension. These propulsive contractions could be generated at the descending and the transverse colons. The removal of the supraspinal influence by spinal transection at T13 or removal of pelvic afferents to the supraspinal center by spinal transection at L abolished the propulsive contractions. Successive lumbar sympathectomy restored the contractions. Lumbar sympathectomy and the successive removal of the supraspinal influence did not affect the propulsive contractions. In both cases, the final exclusion of the sacral segments by pithing of the spinal cord abolished the propulsive contractions. These results suggest that the sacral excitatory reflex mediated via pelvic nerves and the lumbar inhibitory reflex mediated via lumbar sympathetic nerves can function during rectal distension in spinal cats and that the lumbar inhibitory reflex is suppressed by the supraspinal sympathetic inhibitory reflex activated by pelvic afferents in intact cats, as in guinea pigs, resulting in propulsive contractions. 相似文献
35.
Kimata H 《Physiology & behavior》2003,80(2-3):395-398
The effect of kissing on allergen-induced skin wheal responses and plasma neurotrophin levels were studied in 30 normal subjects, 30 patients with allergic rhinitis (AR), and 30 patients with atopic dermatitis (AD). All of the patients with AR or AD are allergic to house dust mite (HDM) and Japanese cedar pollen (JCP). They are all Japanese and they do not kiss habitually. The subject kissed freely during 30 min with their lover or spouse alone in a room with closed doors while listening to soft music. Before and after kissing, skin prick tests were performed using commercial HDM allergen, JCP allergen, as well as histamine and control solution, and wheal responses were measured. Simultaneously, plasma levels of neurotrophin, including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and -4 (NT-4) were measured. Kissing significantly reduced wheal responses induced by HDM and JCP, but not by histamine, and decreased plasma levels of NGF, BDNF, NT-3, and NT-4 in patients with AR or AD, while it failed to do so in normal subjects. These finding indicate that kissing have some implication in the study of neuroimmunology in allergic patients. 相似文献
36.
Takayasu H Motoi T Kanamori Y Kitano Y Nakanishi H Tange T Nakagawara A Hashizume K 《Human pathology》2002,33(8):852-855
The benign epithelial neoplasm liver cell adenoma is rare, especially in childhood. We report 2 such cases, 1 of which was associated with Prader-Willi syndrome. Differential diagnosis of the liver cell adenomas on the basis of histopathologic findings proved difficult and was based on the absence of cellular and nuclear atypia, mitotic activity, and invasive growth. In both cases, immunohistochemical staining demonstrated the nuclear accumulation of beta-catenin, and in 1 case, the tumor cells carried a mutation of the beta-catenin gene. Recently, disregulation of the Wnt/beta-catenin pathway, attributable to abnormalities of the beta-catenin gene, has been reported to be a major event in the development of hepatocellular carcinomas and hepatoblastomas. Our report may be the first to describe the beta-catenin abnormalities in childhood liver cell adenoma. These findings imply that abnormalities of beta-catenin can be an early initiating event in human liver tumorigenesis. 相似文献
37.
Yoshimura R Matsuyama M Hase T Tsuchida K Kuratsukuri K Kawahito Y Sano H Segawa Y Nakatani T 《International journal of molecular medicine》2003,12(6):861-865
Peroxisome proliferator activator-receptor (PPAR)-gamma ligand induces growth arrest of cancer cells through apoptosis. In this study, we examined the effects of PPAR-gamma inhibitors on cell proliferation in renal cell carcinoma (RCC), bladder tumor (BT), and prostatic carcinoma (PC) cell lines. We investigated the inhibitory effect of PPAR-gamma ligands, troglitazone and 15-deoxy-Delta12,14-prostaglandin J2 (15dPGJ2) on RCC, BT and PC-derived cell lines using MTT assay and Hoechst staining. PPAR-gamma ligands (troglitazone and 15dPGJ2) induced the reduction of cell viability with the half-maximal concentration of growth inhibition of RCC, BT, and PC cell lines. Furthermore, counting cells at days 1, 2 and 3, clearly showed marked inhibition of cell proliferation using troglitazone and 15dPGJ2. All PPAR-gamma inhibitors stopped the growth of all RCC, BT and PC cells. Cells treated with PPAR-gamma inhibitors showed chromatin condensation, cellular shrinkage, small membrane-bound bodies (apoptotic bodies), and cytoplasmic condensation. These cellular changes were typically redundant characteristics of apoptosis. PPAR-gamma ligands may mediate potent antiproliferative effects against RCC, BT and PC cells through differentiation. Thus, PPAR-gamma may become a new target in treatment of urological tumors. 相似文献
38.
Hirata I Hioki Y Toda M Kitazawa T Murakami Y Kitano E Kitamura H Ikada Y Iwata H 《Journal of biomedical materials research. Part A》2003,66(3):669-676
Since complement activation is recognized as a common response of the host defense system when an artificial medical device is applied to a patient, great effort has been devoted to studies on the interaction of the complement system with artificial materials. However, some uncertainties remain, partially because of the lack of well characterized surfaces and suitable analytic methods for study of the surface phenomena that occur on artificial materials under physiologic conditions. In this study, we employed self-assembled monolayers (SAMs) and the surface plasmon resonance (SPR) technique to study interactions of the serum complement with well characterized surfaces. Self-assembled monolayers carrying various concentrations of hydroxyl groups were prepared using 11-mercapto-1-undecanol (C11-OH) and one of n-nonanethiol, n-dodecanethiol, and n-hexadecanethiol. The amount of NHS deposition on the SAMs increased with increasing C11-OH content of the SAMs, and the amount of anti-C3b antibody immobilization formed on the NHS deposition layers increased with increasing C11-OH content of the SAMs. These results clearly demonstrate that a large amount of C3b, produced through the activation of the complement system, binds covalently to and is adsorbed by hydroxyl-group-rich surfaces. The combination of SAMs and the SPR technique is suitable for studying the interaction of the complement system with solid surfaces, and the results should give basic information needed for a rational design of biocompatible surfaces on synthetic materials. 相似文献
39.
40.
Control of B cell production by the adaptor protein lnk. Definition Of a conserved family of signal-modulating proteins 总被引:1,自引:0,他引:1
Takaki S Sauer K Iritani BM Chien S Ebihara Y Tsuji K Takatsu K Perlmutter RM 《Immunity》2000,13(5):599-609
Lnk is an SH2 domain-containing adaptor protein expressed preferentially in lymphocytes. To illuminate the importance of Lnk, we generated lnk(-/-) mice. Whereas T cell development was unaffected, pre-B and immature B cells accumulated in the spleens. In the bone marrow, B-lineage cells were proportionately increased, reflecting enhanced production of pro-B cells that resulted in part from hypersensitivity of precursors to SCF, the ligand for c-kit. Hence, Lnk ordinarily acts to regulate B cell production. Further characterization of lnk(-/-) mice also revealed that full-length Lnk is a 68 kDa protein containing a conserved proline-rich region and a PH domain. Lnk is a representative of a multigene adaptor protein family whose members act, by analogy with Lnk, to modulate intracellular signaling. 相似文献