全文获取类型
收费全文 | 20665篇 |
免费 | 1071篇 |
国内免费 | 198篇 |
专业分类
耳鼻咽喉 | 244篇 |
儿科学 | 465篇 |
妇产科学 | 235篇 |
基础医学 | 2631篇 |
口腔科学 | 295篇 |
临床医学 | 1237篇 |
内科学 | 5967篇 |
皮肤病学 | 394篇 |
神经病学 | 1490篇 |
特种医学 | 890篇 |
外科学 | 3424篇 |
综合类 | 73篇 |
预防医学 | 476篇 |
眼科学 | 408篇 |
药学 | 1081篇 |
中国医学 | 34篇 |
肿瘤学 | 2590篇 |
出版年
2024年 | 20篇 |
2023年 | 158篇 |
2022年 | 342篇 |
2021年 | 593篇 |
2020年 | 293篇 |
2019年 | 379篇 |
2018年 | 558篇 |
2017年 | 441篇 |
2016年 | 502篇 |
2015年 | 538篇 |
2014年 | 650篇 |
2013年 | 828篇 |
2012年 | 1297篇 |
2011年 | 1505篇 |
2010年 | 907篇 |
2009年 | 781篇 |
2008年 | 1315篇 |
2007年 | 1379篇 |
2006年 | 1404篇 |
2005年 | 1401篇 |
2004年 | 1407篇 |
2003年 | 1266篇 |
2002年 | 1260篇 |
2001年 | 191篇 |
2000年 | 141篇 |
1999年 | 210篇 |
1998年 | 273篇 |
1997年 | 224篇 |
1996年 | 167篇 |
1995年 | 173篇 |
1994年 | 151篇 |
1993年 | 139篇 |
1992年 | 99篇 |
1991年 | 104篇 |
1990年 | 76篇 |
1989年 | 83篇 |
1988年 | 57篇 |
1987年 | 48篇 |
1986年 | 55篇 |
1985年 | 51篇 |
1984年 | 55篇 |
1983年 | 50篇 |
1982年 | 37篇 |
1981年 | 48篇 |
1980年 | 42篇 |
1979年 | 28篇 |
1978年 | 33篇 |
1977年 | 29篇 |
1976年 | 17篇 |
1975年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
91.
Endothelin synthesis and receptors in human endometrium throughout the normal menstrual cycle 总被引:3,自引:0,他引:3
Kubota Toshiro; Taguchi Makoto; Kamada Shusaku; Imai Taihei; Hirata Yukio; Marumo Fumiaki; Aso Takeshi 《Human reproduction (Oxford, England)》1995,10(8):2204-2213
This study was undertaken to investigate the presence of messengerRNA (mRNA) for prepro-endothelin-I (ET-1) and the known receptorsubtypes (ETA and ETB) in human endometrium at different stagesof the menstrual cycle obtained at hysterectomy. Northern blotanalysis revealed expression of ET-1 mRNA in human endometriumduring the normal menstrual cycle. The concentration of ET-1mRNA in endometrial tissue was greater during the menstrualand proliferative phases than during the ovulatory and secretoryphases. Immunoreactive ET-1 was secreted into the medium ofisolated endometrial stromal cells. Oestradiol and progesteronesignificantly attenuated ET-1 release in endometrial stromalcells cultured for 6 days. ETA and ETB mRNA were also presentin endometrial tissue of the normal cycle. The concentrationof ETA receptor mRNA was greater in the proliferative phasethan in the secretory phase, whereas expression of ETB mRNAincreased in menstrual phase. ET-1 significantly increased extracellularaccumulation of cyclic AMP (cAMP), intracellular generationof inositol phosphates and significantly enhanced DNA synthesisin cultured endometrial stromal cells from the proliferativephase. Our results showed that human endometrial cells synthesizedand released ET-1, and contained ETA and ETB receptors whichwere functionally coupled to phosphoinositide breakdown andto adenylate cyclase with the increase of cAMP by ET-1 stimulation.Our findings suggest that ET-1 may have a potential autocrineand/or paracrine function in human endometrial stromal cells. 相似文献
92.
Cytomegalovirus Isolation from a Chimpanzee with Acute Demyelinating Disease After Inoculation of Multiple Sclerosis Brain Cells 下载免费PDF全文
Zofia Wroblewska Donald Gilden Mary Devlin Eng-Shang Huang Lucy B. Rorke Takeshi Hamada Toru Furukawa Larry Cummins Seymour Kalter Hilary Koprowski 《Infection and immunity》1979,25(3):1008-1015
A strain of cytomegalovirus (CMV) was isolated during the third subcultivation of explants from the left frontal lobe of a chimpanzee that developed paralysis more than 3 years after intracerebral inoculation at birth with brain cell cultures derived from a patient with multiple sclerosis. Another strain of CMV was also isolated from a lymph node culture taken from the same chimp. The isolates, designated MZM-13 and MZM-14, produced a cytopathic effect characteristic for CMV when inoculated into brain, ganglion, or fibroblast cultures of human or simian origin. Infected cells contained characteristic Cowdry A intranuclear as well as intracytoplasmic inclusion bodies, and 100-nm spherical herpes-like virus particles were detected by electron microscopy in the nucleus and cytoplasm of infected cells. Virus was further identified as CMV with convalescent human anti-CMV serum. Complement-fixing antibody to CMV was present at a titer of 1:32 when the acutely ill chimpanzee was sacrificed. No antibody was detected at birth or at 1 or 2 years of age. A newborn chimpanzee inoculated intracerebrally with MZM-13 developed clinically asymptomatic lesions in the central nervous system characterized by acute and chronic inflammation and degeneration of myelin in cranial and spinal nerve roots. Restriction endonuclease analysis of viral deoxyribonucleic acid isolated from these two viruses indicated that MZM-13 and MZM-14 are identical and are closely related to chimpanzee CMV. No similarity in restriction endonuclease fragment patterns was found between MZM virus and the Towne and Clegg strains of human CMV. 相似文献
93.
Ken SAITO Hideo SHIMIZU Takeshi YOKOYAMA Katsuya KAWATA Takanori MATSUMURA Yasuhiko MORIOKA 《Pathology international》1983,33(2):249-256
Four cases of Ischemic enterocolitis without arterio–occlusive lesion were described. Three cases were associated with sigmoid colon carcinomas. Ischemic lesions developed anal to the carcinomas in two cases, and oral to sigmoidostomy to relieve intestinal obstruction by carcinoma in one case. One other case was associated with inguinal hernia. Grossly, ischemic lesions involved relatively short intestinal segments, and the ischemic colonic lesions were not related to teniae coli. Extensive veno–occlusive lesions were discovered in a case of ischemic stricture of the ileum, which had been incarcerated in the right inguinal hernia. Reversible mechanical occlusion of the intestinal vessels caused by transient or recurrent intestinal strangulation is the most probable cause of these ischemic lesions., ACTA PATHOL. JPN. 33: 249–256, 1983. 相似文献
94.
Social isolation stress augments angiogenesis induced by colon 26-L5 carcinoma cells in mice 总被引:3,自引:0,他引:3
Wu W Murata J Murakami K Yamaura T Hayashi K Saiki I 《Clinical & experimental metastasis》2000,18(1):1-10
We have previously shown that tumor necrosis factor-α (TNF-α), which is an important angiogenesis-related factor, was over-secreted in male BALB/c mice under social isolation stress as compared with the control, and closely associated with a remarkable elevation of tumor invasion and metastasis of colon 26-L5 carcinoma cells. In the present study, we explored the effect of isolation stress on the angiogenesis caused by colon 26-L5 carcinoma cells in vivo and in vitro. Social isolation lead to the enhancement of tumor growth after intrahepatic implantation with a fragment of colon 26-L5 tumor. Angiogenic response (number of vessels oriented towards tumor mass) and tumor growth (size) were significantly increased in the socially isolated mouse relative to that in the group-housed mice. Furthermore, higher protein level of hepatic TNF-α was found in the stressed mice than that in the control. Expression of mRNA for vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) were also elevated in the tumor regions and liver tissues of the stressed mice in comparison with that in group-housed mice. On the other hand, hepatic sinusoidal endothelial (HSE) cells treated with TNF-α exhibited a marked promotion of the migration, invasion, expression of mRNA for matrix metalloproteinase (MMP)-9, and tube-like formation, but no cytotoxicity against the cells in vitro. The above data suggest that the social isolation stress augmented the tumor-induced angiogenesis probably by up-regulating the angiogenesis-related factors, including TNF-α, VEGF and HGF, and consequently mediating the functions of endothelial cells such as migration, invasion, and tube-like formation. 相似文献
95.
96.
97.
Kadota K Satoh E Ochiai M Inoue N Tsuji N Igarashi I Nagasawa H Mikami T Claveria FG Fujisaki K 《Parasitology research》2002,88(8):781-784
Phenol oxidase (PO, EC 1.10.3.1) activity was detected in the hemolymph of the fourth instar nymphs of the argasid tick, Ornithodoros moubata, with peak levels corresponding to the days before the majority of the nymphs had molted, suggestive of a protective role of PO during the ecdysial phase. Higher PO activity was detected in plasma relative to the hemolymph and was negligible in hemocytes. The concentration of the hemolymph and plasma assayed clearly influenced the level of PO activity, and was significantly reduced ( P<0.005) after treatment with 1-phenyl-2 thiourea, a specific PO inhibitor. This is the first report of the existence of PO in the hemolymph and plasma of a soft tick species. The regulation of PO activity and its precise role in soft tick immunity, particularly during the ecdysial phase, are interesting and need to be examined further. 相似文献
98.
Yoshinori Seko Shigeru Ishiyama Toshiro Nishikawa Takeshi Kasajima Michiaki Hiroe Shin Suzuki Sugao Ishiwata Sachio Kawai Yuetsu Tanaka Miyuki Azuma Tetsuji Kobata Hideo Yagita Ko Okumura Ryozo Nagai 《Cardiovascular pathology》2002,11(3):166-170
BACKGROUND: T-cell-mediated myocardial damage is known to be involved in acute myocarditis and dilated cardiomyopathy. Recently, we found that tumor necrosis factor (TNF) ligand superfamily costimulatory molecules, especially 4-1BBL, played an important role in the myocardial damage of murine acute viral myocarditis. METHODS AND RESULTS: To investigate the roles for CD27L, CD30L, OX40L and 4-1BBL, which belong to TNF ligand superfamily, in the development of acute myocarditis and dilated cardiomyopathy, we analyzed the expression of these antigens in the myocardial tissues of patients with acute myocarditis and dilated cardiomyopathy. We also examined expression of the receptors for these molecules, CD27, CD30, OX40 and 4-1BB, which belong to TNF receptor superfamily, on the infiltrating cells. Strong expression of CD27L, CD30L and 4-1BBL and weak to moderate expression of OX40L was found in the cardiac myocytes of patients with acute myocarditis. Moderate expression of CD27L, CD30L and 4-1BBL and weak expression of OX40L was found on the cardiac myocytes of patients with dilated cardiomyopathy. Most of the infiltrating cells expressed CD27, CD30 and 4-1BB and a part of the infiltrating cells expressed OX40. CONCLUSIONS: Our findings suggest that expression of TNF ligand superfamily costimulatory molecules on cardiac myocytes may play a role in the cell-mediated myocardial damage in patients with acute myocarditis and dilated cardiomyopathy as in murine viral myocarditis. 相似文献
99.
TCR repertoire in early fetal mouse thymus 总被引:1,自引:0,他引:1
Ohki-Hamazaki Hiroko; Makino Yasuhiko; Kanno Masamoto; Koseki Haruhiko; Akasaka Takeshi; Taniguchi Masaru 《International immunology》1995,7(3):493-499
We investigated the rearrangement and expression of TCR genesin mouse fetal thymus organ culture, a system that avoids subsequententry of hematopoietic precursor cells. The first observablerearranged TCR gene was homogeneous V2-J2, detectable as earlyas fetal day 11 (d11) in the thymic primordla. The productiveTCR was homogeneous V5-J1, first detectable in d13 thymocytes,followed by adult-type TCR (V4 and V7). Sequence analysis ofTCR revealed five types of V-J junctional sequences. In thevery early stage, a homogeneous V-J junction is generated viaa short homology sequence in the coding region (Type I), whilea short homology sequence in the P-nucleotlde rather than thecoding region is used in the following stage (Type II). In thelater embryonic stages, diverse V-J junctions are generatedby well-known mechanisms, such as P-nucleotide (Type III), N-regioninsertion (Type IV) or trimming of the coding ends (Type V).These findings suggest that the generation of homogeneous TCR (V2 and V5) in the early fetal stages is due to the intrinsicrearrangement mechanisms and is in stage specific manner. 相似文献
100.
Hong-Guo Jin Hiroshi Yamashita Takeshi Nakamura Hiromasa Fukuba Tetsuya Takahashi Masanori Hiji Tatsuo Kohriyama Masayasu Matsumoto 《Neuroscience letters》2008
Synphilin-1 represents a cytoplasmic protein that interacts with α-synuclein and localizes close to synaptic vesicles. The interaction of synphilin-1 with several proteins involved in Parkinson's disease suggests that it might be involved in the pathogenesis of the disease. Nonetheless, the function of synphilin-1 remains unclear. In the present study, we generated transgenic mice expressing human synphilin-1 under the prion protein promoter. Synphilin-1 was widely expressed in neurons in the brain including the substantia nigra, where massive loss of dopamine neurons was not observed. In the transgenic mouse brain, synphilin-1 protein was polyubiquitinated, and partially insoluble. Although modified-SHIRPA revealed no significant difference in behavior and morphology, the reduced rotarod performance and step length were observed in transgenic mice as compared with non-transgenic littermates. Synphilin-1 might be involved in motor function, and its accumulation in the central nervous system can cause motor impairments. 相似文献