全文获取类型
收费全文 | 15515篇 |
免费 | 712篇 |
国内免费 | 92篇 |
专业分类
耳鼻咽喉 | 132篇 |
儿科学 | 292篇 |
妇产科学 | 272篇 |
基础医学 | 1834篇 |
口腔科学 | 418篇 |
临床医学 | 1010篇 |
内科学 | 4068篇 |
皮肤病学 | 372篇 |
神经病学 | 1195篇 |
特种医学 | 546篇 |
外国民族医学 | 2篇 |
外科学 | 2592篇 |
综合类 | 101篇 |
预防医学 | 444篇 |
眼科学 | 361篇 |
药学 | 1075篇 |
中国医学 | 35篇 |
肿瘤学 | 1570篇 |
出版年
2023年 | 79篇 |
2022年 | 178篇 |
2021年 | 292篇 |
2020年 | 148篇 |
2019年 | 185篇 |
2018年 | 280篇 |
2017年 | 208篇 |
2016年 | 268篇 |
2015年 | 316篇 |
2014年 | 340篇 |
2013年 | 474篇 |
2012年 | 755篇 |
2011年 | 852篇 |
2010年 | 492篇 |
2009年 | 413篇 |
2008年 | 743篇 |
2007年 | 744篇 |
2006年 | 755篇 |
2005年 | 847篇 |
2004年 | 761篇 |
2003年 | 744篇 |
2002年 | 752篇 |
2001年 | 435篇 |
2000年 | 423篇 |
1999年 | 448篇 |
1998年 | 226篇 |
1997年 | 207篇 |
1996年 | 175篇 |
1995年 | 147篇 |
1994年 | 138篇 |
1993年 | 125篇 |
1992年 | 355篇 |
1991年 | 316篇 |
1990年 | 286篇 |
1989年 | 324篇 |
1988年 | 261篇 |
1987年 | 247篇 |
1986年 | 233篇 |
1985年 | 190篇 |
1984年 | 147篇 |
1983年 | 96篇 |
1982年 | 52篇 |
1980年 | 62篇 |
1979年 | 87篇 |
1978年 | 69篇 |
1977年 | 55篇 |
1975年 | 57篇 |
1974年 | 71篇 |
1973年 | 68篇 |
1972年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Ryuei Maeda Nobuo Ihara Reiko Takada Tadashi Kondo Emyo Nakano Toshiko Yamato 《Pathology international》1971,21(1):151-155
A new vital staining method with neutral red has been established where by cerebral ganglion cells can be stained in vivo . 相似文献
52.
Inflammation Research - 相似文献
53.
Characterization of a Helicobacter pylori neutrophil-activating protein. 总被引:25,自引:0,他引:25 下载免费PDF全文
D J Evans Jr D G Evans T Takemura H Nakano H C Lampert D Y Graham D N Granger P R Kvietys 《Infection and immunity》1995,63(6):2213-2220
Helicobacter pylori-associated gastritis is mainly an inflammatory cell response. In earlier work we showed that activation of human neutrophils by a cell-free water extract of H. pylori is characterized by increased expression of neutrophil CD11b/CD18 and increased adhesiveness to endothelial cells. The work reported here indicates that the neutrophil-activating factor is a 150,000-molecular-weight protein (150K protein). Neutrophil proadhesive activity copurified with this protein, which is a polymer of identical 15K subunits. Specific antibody, prepared against the purified 15K subunit, neutralized the proadhesive activity of the pure protein and of water extracts obtained from different strains of H. pylori. The gene (napA) for this protein (termed HP-NAP, for H. pylori neutrophil-activating protein) was detected, by PCR amplification, in all of the H. pylori isolates tested; however, there was considerable strain variation in the level of expression of HP-NAP activity in vitro. HP-NAP could play an important role in the gastric inflammatory response to H. pylori infection. 相似文献
54.
A case of polypoid carcinosarcoma of the esophagus is presented. Histologically the bulk of the tumor consisted of a sarcomatous tissue having large foci of osseous and cartilagenous differentiation and infiltrating deeply the wall, whereas a superficially, invasive squamous cell carcinoma associated with in-situ carcinoma was located at the base and luminal surface of the polypoid tumor. Intermingling of the carcinomatous and sarcomatous elements was found only in areas where they appeared to be collided. Ultrastructurally the sarcomatous portion contained cells with fibroblastic features but with no typical epithelial characteristics. Immunoperoxidase staining of the paraffin-embedded histologic sections for keratin proteins revealed, however, some positive spindle cells indicative of epithelial nature in the sarcomatous area, but the great majority of the sarcoma cells were devoid of keratin. These combined findings strongly suggest that the sarcomatous component in our case of true carcinosarcoma is derived from mesenchymal transformation (metaplasia) of the squamous carcinoma cells. The findings were discussed in light of the previous pertinent literature. 相似文献
55.
56.
Vidalin O Fournillier A Renard N Chen M Depla E Boucreux D Brinster C Baumert T Nakano I Fukuda Y Liljeström P Trépo C Inchauspé G 《Virology》2000,276(2):259-270
Replicating and nonreplicating nucleic acid-based vaccines as well as Semliki Forest-recombinant Viruses (rSFVs) were evaluated for the development of a vaccine against hepatitis C virus (HCV). Replicating SFV-DNA vaccines (pSFV) and rSFVs expressing HCV core or E2 antigens were compared with classical CMV-driven plasmids (pCMV) in single or bimodal vaccine protocols. In vitro experiments indicated that all vaccine vectors produced the HCV antigens but to different levels depending on the antigen expressed. Both replicating and nonreplicating core-expressing plasmids induced, upon injection in mice, specific comparable CTL responses ranging from 10 to 50% lysis (E:T ratio 100:1). Comparison of different injection modes (intramuscular versus intraepidermal) and the use of descalating doses of DNA (1-100 microgram) did not show an increased efficacy of the core-SFV plasmid compared with the CMV-driven one. Surprisingly, rSFVs yielded either no detectable anticore CTL or very low anti-E2 antibody titers following either single or bimodal administration together with CMV-expressing counterparts. Prime-boost experiments revealed, in all cases, the superiority of DNA-based only vaccines. The anti-E2 antibody response was evaluated using three different assays which indicated that all generated anti-E2 antibodies were targeted at similar determinants. This study emphasizes the potential of DNA-based vaccines for induction of anti-HCV immune responses and reveals an unexpected and limited benefit of SFV-based vaccinal approaches in the case of HCV core and E2. 相似文献
57.
T Katagiri T Nakano K Ueno Y Ohsugi M Fujiwara 《International archives of allergy and applied immunology》1985,78(3):233-236
Soluble extract (sEx) was prepared from lymphoid cells of MRL/Mp-lpr/lpr(MRL/l) mice with early lupus nephritis and also of MRL/Mp-+/+ (MRL/n) mice. sEx from lymph node and spleen T cells of MRL/l mice had an activity for B cells to differentiate into immunoglobulin-producing cells but that of MRL/n mice did not show such an activity. sEx of MRL/l mice also enhanced the in vitro response of B cells to a suboptimal dose of lipopolysaccharide. Implication of these phenomena in the development of lupus nephritis is discussed. 相似文献
58.
The effect of vitamin A depletion on antigen-stimulated trapping of peripheral lymphocytes in lymphatic organs was studied in rats. Distribution of [3H]-uridine-labelled syngenic peripheral lymphocytes was quantified by assaying radioactive content of brachial and axillary lymph nodes, spleen and liver of normal and vitamin A-depleted F344/Ducrj rats immunized with sheep red blood cells. Localization of labelled cells in the ipsilateral brachial lymph nodes of the normal rats was stimulated by three times upon immunization with sheep erythrocytes as compared with the contralateral nodes. Recruitment of cells in axillary lymph nodes, spleen and liver was not significantly different from non-immunized values. The vitamin A-depleted rats exhibited marked deterioration in antigen-stimulated trapping of labelled cells in the draining brachial lymph nodes. These results suggest that this effect of vitamin A depletion is due to derangement of integrity of lymphocyte-trapping mechanism in the draining lymph nodes and not to any change in nature of lymphocytes per se. 相似文献
59.
Colloidal gold labeled-testosterone-bovine serum albumin conjugate (testosterone-BSA-gold) injected into the vascular system of rats is taken up by endocytosis into round spermatids. Based on observation of silver deposits indicating testosterone-BSA-gold with silver enhancement, we have suggested that testosterone-BSA-gold enters the nuclei through not only the postacrosomal nuclear envelope but also the subacrosomal nuclear envelope (SNE) via the acrosome (Nishimura and Nakano, 1997). However, it was unclear how testosterone-BSA-gold in the acrosome entered the nucleoplasm. Spermatids showing silver deposits on the subacrosomal space were observed under electron microscope without silver enhancement, to clarify the courses of translocation. In the spermatids, vesicles with the gold particles were seen in the subacrosomal space. Some of the vesicles were in contact with the SNE. A part of the outer nuclear membrane projected into the space. Furthermore, local single-bilayer nuclear membranes, which seemed to partially lack nuclear lamina, were present in the SNE. These results indicate the possibility that the vesicles mediate the transport of testosterone-BSA-gold from acrosome to nucleus, and that the vesicle membrane fuses with not only the outer nuclear membrane but also a shared bilayer in the SNE. 相似文献
60.
Ikegaya H Iwase H Zheng HY Nakajima M Sakurada K Takatori T Fukayama M Kitamura T Yogo Y 《Journal of virological methods》2005,126(1-2):37-43
Recently genotyping of JC virus (JCV) DNA in renal tissue was reported to be useful to identify the geographic origin of unidentified cadavers. In the above study, autopsied tissue samples without storage or stored in a frozen state were used. This study examined JCV DNA sequence modifications caused by formalin-fixation, in an attempt to elucidate whether formalin-fixed, paraffin-embedded tissue samples can also be used to determine the genotypes of JCV DNA in the kidney. In four cases, a 610 bp typing region of the JCV genome was PCR-amplified from renal tissues stored for 1 year in three different states: frozen at -80 degrees C [Amaker, B.H., Chandler, F.W., Huey, L.O., Colwell, R.M., 1997. Molecular detection of JC virus in embalmed, formalin-fixed, paraffin-embedded brain tissue. J. Forensic Sci., 1157-1159], formalin-fixed, paraffin-embedded [Ault, G.S., Stoner, G.L., 1992. Two major types of JC virus defined in progressive multifocal leukoencephalopathy brain by early and late coding region DNA sequences. J. Gen. Virol. 73, 2669-2678], and soaked in 5% formalin [Baksh, F.K., Finkelstein, S.D., Swalskey, P.A., Stoner, G.L., Ryschkewitsch, C.F., Randhawa, P.R., 2001. Molecular genotyping of BK and JC virus in human polyomavirus-associated interstitial nephritis after renal transplantation. Am. J. Kidney Dis. 38 (2), 354-365]. The amplified fragments were cloned, and the resultant clones were sequenced. In frozen samples, single sequences ('original' sequences) were detected in all cases. In formalin-fixed, paraffin-embedded samples, not only the original sequences but also those with 1-6 base substitutions were detected. From formalin-soaked samples, the original sequences and those with 1-5 and 10-13 substitutions were detected. The genotyping of JCV DNA was not hampered by the presence of 1-6 substitutions, but a shift in JCV genotypes was observed in sequences with 10-13 substitutions. Thus, it was concluded that the genotypes of JCV DNA in the kidney can be determined only with specimens stored in a frozen state or formalin-fixed for a short time. 相似文献