全文获取类型
收费全文 | 16830篇 |
免费 | 890篇 |
国内免费 | 109篇 |
专业分类
耳鼻咽喉 | 151篇 |
儿科学 | 270篇 |
妇产科学 | 141篇 |
基础医学 | 2012篇 |
口腔科学 | 496篇 |
临床医学 | 1076篇 |
内科学 | 4412篇 |
皮肤病学 | 470篇 |
神经病学 | 1043篇 |
特种医学 | 637篇 |
外科学 | 2966篇 |
综合类 | 63篇 |
预防医学 | 458篇 |
眼科学 | 323篇 |
药学 | 1371篇 |
中国医学 | 30篇 |
肿瘤学 | 1910篇 |
出版年
2023年 | 181篇 |
2022年 | 340篇 |
2021年 | 544篇 |
2020年 | 293篇 |
2019年 | 419篇 |
2018年 | 515篇 |
2017年 | 376篇 |
2016年 | 406篇 |
2015年 | 383篇 |
2014年 | 524篇 |
2013年 | 610篇 |
2012年 | 988篇 |
2011年 | 990篇 |
2010年 | 584篇 |
2009年 | 485篇 |
2008年 | 820篇 |
2007年 | 953篇 |
2006年 | 906篇 |
2005年 | 917篇 |
2004年 | 867篇 |
2003年 | 815篇 |
2002年 | 819篇 |
2001年 | 354篇 |
2000年 | 387篇 |
1999年 | 362篇 |
1998年 | 171篇 |
1997年 | 144篇 |
1996年 | 140篇 |
1995年 | 105篇 |
1994年 | 97篇 |
1993年 | 86篇 |
1992年 | 216篇 |
1991年 | 187篇 |
1990年 | 184篇 |
1989年 | 181篇 |
1988年 | 171篇 |
1987年 | 156篇 |
1986年 | 134篇 |
1985年 | 133篇 |
1984年 | 106篇 |
1983年 | 85篇 |
1982年 | 49篇 |
1979年 | 58篇 |
1978年 | 46篇 |
1977年 | 48篇 |
1973年 | 49篇 |
1972年 | 41篇 |
1971年 | 42篇 |
1969年 | 49篇 |
1968年 | 51篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Endo Y Yamauchi K Tsutsui Y Ishihara Z Yamazaki F Sagawa S Shiraki K 《The Japanese journal of physiology》2002,52(5):421-427
To investigate the possible involvement of the sympathetic nervous system in pressor response during water drinking, muscle sympathetic nerve activity (MSNA), blood pressure (BP), and heart rate (HR) were continuously measured in healthy young volunteers throughout the experiments of a 5-min control, 2 min of drinking 500 ml water, and a 28-min recovery. To avoid the effects of water passing through the oropharyngeal and esophageal regions and/or effects of swallowing, an equal amount of water was directly infused to the stomach through a stomach tube for 2 min. Water drinking caused a transient increase in mean arterial pressure (MAP) and HR immediately after drinking (DeltaMAP, 12.6 +/- 2.1 mmHg; DeltaHR, +19.9 +/- 1.7 beats/min at the peak). An abrupt decrease of MSNA was observed directly during water drinking (Deltaburst rate, -6.9 +/- 1.3 bursts/min; Deltatotal activity, -2,606 +/- 491 U/min), and it increased to the baseline level thereafter. Gastric infusion had little or no effect on MAP, HR, and MSNA. The present study demonstrated that a pressor response during water drinking was associated with the attenuation of MSNA and not generated by gastric infusion of water at the same rate as in this drinking manner. In conclusion, the rapid rise in BP might be caused through stimulations from the oropharyngeal region, swallowing-induced factors, and/or a feedforward mechanism by a central descending signal from the higher brain centers. 相似文献
82.
83.
84.
Shinkai T De Luca V Zai G Shaikh S Matsumoto C Arnold PD Hwang R King N Trakalo J Potapova N Wong G Hori H Wong AH Ohmori O Nakamura J Kennedy JL 《Psychiatric genetics》2004,14(3):177-180
OBJECTIVE: Oxidative stress such as free radical-mediated neuronal dysfunction may be involved in the pathophysiology of schizophrenia. The human glutathione peroxidase (GPX1) is a selenium-dependent enzyme, which plays an important role in the detoxification of free radicals. We therefore hypothesized that the GPX1 gene, which is located on chromosome 3p21.3, may be involved in the pathophysiology of schizophrenia. The aim of this study is to examine whether a potentially functional polymorphism, a proline (Pro) to leucine (Leu) substitution at codon 197 (Pro197Leu) of the human GPX1 gene, is associated with susceptibility to schizophrenia. METHODS: We genotyped the Pro197Leu polymorphism in a total of 113 nuclear families that had a proband with schizophrenia. Genetic association was tested using the transmission disequilibrium test (TDT), the sib transmission disequilibrium test (STDT), and the family-based association test (FBAT). RESULTS: The minor allele (Leu) frequency was calculated to be 0.282. We could not find significant transmission disequilibrium of the alleles for the Pro197Leu polymorphism in the GPX1 gene in association with the presence of schizophrenia in our family sample (TDT, chi2=0.03, degrees of freedom=1, P=0.86; combined TDT-STDT, Z'=-0.052, P=0.47; FBAT, Z=0.000, P=1.000). CONCLUSION: The results of this study suggest that the GPX1 polymorphism is unlikely to be associated with susceptibility to schizophrenia. 相似文献
85.
Saijo K Schmedt C Su IH Karasuyama H Lowell CA Reth M Adachi T Patke A Santana A Tarakhovsky A 《Nature immunology》2003,4(3):274-279
The nature of signals that govern the development of immunoglobulin heavy chain-dependent B cells is largely unknown. Using mice deficient for the B cell-expressed Src-family protein tyrosine kinases (SFKs) Blk, Fyn and Lyn, we show an essential role of these kinases in pre-B cell receptor (pre-BCR)- mediated NF-kappaB activation and B cell development. This signaling defect is SFK specific, as a deficiency in Syk, which controls pre-B cell development, does not affect NF-kappaB induction. Impaired NF-kappaB induction was overcome by the activation of protein kinase C (PKC)-lambda, thus suggesting the involvement of PKC-lambda in pre-BCR-mediated SFK-dependent activation of NF-kappaB. Our data show the existence of a functionally distinct SFK signaling module responsible for pre-BCR-mediated NF-kappaB activation and B cell development. 相似文献
86.
Takahiro Tsujimura Masashi Takeda Nobuyuki Terada Hiroshi Uramoto 《Pathology international》1991,41(8):642-646
Two cases of peritoneal papillary carcinoma are reported. The patient in the first case was a 71-year-old woman with symptoms of obstructive ileus. Laparotomy revealed a tumor in the omentum involving the transverse colon, and several small tumors in the peritoneum and pelvic wall. However, no primary site of the tumor was seen in the ovary, pancreas, or gastrointestinal tract. The patient in the second case was a 44-year-old woman with carcinomatous peritonitis. Postmortem examination revealed multiple tumors in the peritoneum, omentum, and pelvic wall. Tumors were also found in the cortex with mild invasion of the underlying parenchyma of the bilateral ovaries, although these lesions were thought to be metastatic. The histologic features of the tumor in both cases were those of tubulopapillary adenocarcinoma containing scattered psammoma bodies. The cells were positive with the PAS D technique, but negative with alcian blue staining. In both cases, the serum levels of CA-125 were considerably elevated, and the tumor cells showed positivity for CA-125, S 100 protein, cytokeratin and EMA by im-munohistochemistry. The present cases were most likely peritoneal serous papillary adenocarcinoma derived from extraovarian peritoneal mesothelium with miillerian potential, being different from the usual type of diffuse malignant mesothelioma. Acta Pathol Jpn 41: 642-646, 1991. 相似文献
87.
88.
Hohdatsu T Sasagawa T Yamazaki A Motokawa K Kusuhara H Kaneshima T Koyama H 《Archives of virology》2002,147(8):1517-1529
Summary. Feline immunodeficiency virus (FIV) isolates from domestic cats have been classified into five subtypes, designated A, B, C, D
and E. Although many FIV-infected cats may have frequent contact with multiple strains of FIV, they usually become infected
with a single FIV subtype. In the present study, we demonstrate that peripheral blood mononuclear cells (PBMC) of FIV infected
cats were resistant to exogenous FIV (second virus) replication in vitro and that the resistance of these PBMC was mediated
by CD8+ T cells. In cats with a low anti-FIV activity of CD8+ T cells, the proviral DNA of the second virus inoculated into PBMC was detected intracellularly, and both the second and
the originally infecting strain (original virus) were produced in the culture supernatant. In contrast, in cats with a high
anti-FIV activity of CD8+ T cells, both the proviral DNA of the second virus and the original virus were detected in PBMC intracellularly, but neither
virus was produced in the culture supernatant. However, when PBMCs from these cats were depleted of CD8+ T cells, the RNA of both viruses was detected in the culture supernatant. These results suggest that CD8+ T cells inhibit the late phase of FIV replication after viral integration. Moreover, the inhibition was also effective against
FIV strains of different subtypes from that of the original strain. It appears that the CD8+ T cell-mediated immune response plays important roles in the maintenance of an asymptomatic state in FIV-infected cats and
their resistance to superinfection.
Received December 11, 2001; accepted March 22, 2002 Published online June 21, 2002 相似文献
89.
90.
Constitutive Expression of a Bacterial Pattern Recognition Receptor, CD14, in Human Salivary Glands and Secretion as a Soluble Form in Saliva 下载免费PDF全文
Akiko Uehara Shunji Sugawara Kouichi Watanabe Seishi Echigo Mitsunobu Sato Takahiro Yamaguchi Haruhiko Takada 《Clinical and Vaccine Immunology : CVI》2003,10(2):286-292
Saliva contains a number of proteins and glycoproteins that protect oral tissues, but little is known about the role of human saliva in innate immunity. Here we showed that human major salivary gland cells constitutively expressed a bacterial pattern recognition receptor, CD14, by immunohistochemistry. Human salivary gland cells in culture express CD14 mRNA and a 55-kDa CD14 protein in, but not on the cells, and secrete a soluble form with the same molecular mass. Human whole saliva contains a 55-kDa CD14, and the concentration of parotid saliva was 10-fold higher than whole saliva, which is comparable to that of serum CD14. Levels of CD14 in unstimulated whole and parotid saliva were unchanged before and after a meal and between unstimulated and stimulated saliva, indicating that saliva CD14 is constitutively secreted into the oral cavity. In contrast, lipopolysaccharide (LPS)-binding protein was below the detectable level. The saliva CD14 is functionally active in that it mediated the activation of CD14-lacking intestinal epithelial cells by LPS in a Toll-like receptor 4-dependent manner. These results suggested that saliva CD14 is important for the maintenance of oral health and possibly intestinal homeostasis. 相似文献