全文获取类型
收费全文 | 2587篇 |
免费 | 152篇 |
国内免费 | 2篇 |
专业分类
2741篇 |
出版年
2022年 | 20篇 |
2021年 | 38篇 |
2020年 | 21篇 |
2019年 | 12篇 |
2018年 | 37篇 |
2017年 | 41篇 |
2016年 | 52篇 |
2015年 | 94篇 |
2014年 | 113篇 |
2013年 | 136篇 |
2012年 | 174篇 |
2011年 | 173篇 |
2010年 | 100篇 |
2009年 | 116篇 |
2008年 | 151篇 |
2007年 | 162篇 |
2006年 | 165篇 |
2005年 | 141篇 |
2004年 | 130篇 |
2003年 | 150篇 |
2002年 | 127篇 |
2001年 | 51篇 |
2000年 | 59篇 |
1999年 | 51篇 |
1998年 | 36篇 |
1997年 | 29篇 |
1996年 | 22篇 |
1995年 | 22篇 |
1994年 | 18篇 |
1993年 | 17篇 |
1992年 | 27篇 |
1991年 | 35篇 |
1990年 | 21篇 |
1989年 | 20篇 |
1988年 | 13篇 |
1987年 | 15篇 |
1986年 | 18篇 |
1985年 | 20篇 |
1984年 | 5篇 |
1983年 | 14篇 |
1982年 | 12篇 |
1981年 | 5篇 |
1980年 | 8篇 |
1979年 | 10篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1970年 | 9篇 |
排序方式: 共有2741条查询结果,搜索用时 0 毫秒
1.
2.
W Nakamura K Komatsu K Kageyama 《Comptes rendus des séances de la Société de biologie et de ses filiales》1985,179(4):558-562
Comparison was made between the effects of local irradiation of gamma rays, s. c. injection of cis-diamminedichloroplatinum (II) (CDDP), systemic hyperthermia and their combinations on the i. m. transplanted murine mastocytoma. Increase of the mean survival time (M. S. T.) by a factor of 1.72 and of 1.68 was achieved by a single irradiation at 20 Gy, given on day 5 after transplantation, and by injections of CDDP at 2 mg/kg, given s. c. on days 5 and 12 after transplantation, respectively. Increase of M. S. T. by a factor of 1.10 which was achieved with systemic hyperthermia of 41.8 degrees C of the core body temperature for 5 min, given twice, on days 5 and 12 after transplantation, was not statistically significant. The most effective one among all possible combinations within the 3 modalities was that of radiation and CDDP. Increase of M. S. T. was by a factor of 4.01. 相似文献
3.
M. Nakamura M. Oda Y. Yonei N. Tsukada H. Komatsu K. Kaneko M. Tsuchiya 《Histochemistry and cell biology》1985,83(6):479-487
Summary The muscarinic cholinergic innervation of the rat gastric mucosa was investigated by localizing the muscarinic receptors using a tritiated muscarinic antagonist, pirenzepine. Radioautography was performed by freeze drying stomach tissue, which was then embedded in Epon and wet sectioned with ethylene glycol, and dry mounting on emulsion film by the wire-loop method to prevent loss of the labelled substance during fixation and the radioautographic procedure. Light and electron microscopy showed that the specific pirenzepine-binding sites were localized predominantly on parietal cells, chief cells and perivascular plexuses. Analysis of the grain distribution on parietal cells revealed that the silver grains corresponding to the pirenzepine-binding sites were mainly on the basolateral plasma membrane. On the other hand, the surface mucous or mucous neck cells had few pirenzepine-binding sites. 相似文献
4.
5.
A peptide fragment Fr. 17 (Lys1-Cys-Asn27 Leu129-Cys-Ala122) of hen egg white lysozyme (HL) was previously found to retain at least one antigenic determinant region of the native protein. In this work a highly purified preparation of Fr. 17, contaminated with less than 0.01% HL and less than 1% of other fragments was found to be strongly immunogenic to rabbits. The kinetic patterns of antibody formation against Fr.17, assayed by passive hemagglutination (PHA), were quite different from those of antibody formation against HL. The specificity of the antibody elicited to Fr. 17 was mainly directed to the Fr. 9-10-a region (Ala11-Asn27) while that of the antibody elicited to the Fr. 17 region in native HL was directed to the Fr. 15-b region (Lys1-Cys-Ala10 Leu129-Cys-Trp123). It is concluded that in the process of antibody formation, the recognition of the Fr. 17 region in native HL is different from that of fragment Fr. 17. 相似文献
6.
Toba T Murata K Futamura J Nakanishi K Takahashi B Takemoto N Tomino M Nakatsuka T Imajo S Goto M Yamamura T Miyake S Annoura H 《Bioorganic & medicinal chemistry》2012,20(9):2850-2859
A series of truncated analogs of α-galactosylceramide with altered ceramide moiety was prepared, and evaluated for Th2-biased response in the context of IL-4/IFN-γ ratio. Phytosphingosine-modified analogs including cyclic, aromatic and ethereal compounds as well as the C-glycoside analog of OCH (2) with their cytokine inducing profile are disclosed. 相似文献
7.
Shin-ichiro Kurimoto Kyoko Suzuki Mamoru Okasaka Yoshiki Kashiwada Olimjon K. Kodzhimatov Yoshihisa Takaishi 《Phytochemistry letters》2012,5(4):729-733
Five new eudesmane- (1–5), two new guaiane- (6 and 7) and one new germacrane-type (8) sesquiterpene lactone glucosides were isolated from the H2O-soluble fraction of the roots of Ferula varia. Their structures were elucidated by extensive spectroscopic analyses. The absolute configuration of 1 was determined by modified Mosher's method. 相似文献
8.
9.
Superoxide production at phagosomal cup/phagosome through beta I protein kinase C during Fc gamma R-mediated phagocytosis in microglia 总被引:2,自引:0,他引:2
Ueyama T Lennartz MR Noda Y Kobayashi T Shirai Y Rikitake K Yamasaki T Hayashi S Sakai N Seguchi H Sawada M Sumimoto H Saito N 《Journal of immunology (Baltimore, Md. : 1950)》2004,173(7):4582-4589
Protein kinase C (PKC) plays a prominent role in immune signaling. To elucidate the signal transduction in a respiratory burst and isoform-specific function of PKC during FcgammaR-mediated phagocytosis, we used live, digital fluorescence imaging of mouse microglial cells expressing GFP-tagged molecules. betaI PKC, epsilonPKC, and diacylglycerol kinase (DGK) beta dynamically and transiently accumulated around IgG-opsonized beads (BIgG). Moreover, the accumulation of p47(phox), an essential cytosolic component of NADPH oxidase and a substrate for betaI PKC, at the phagosomal cup/phagosome was apparent during BIgG ingestion. Superoxide (O(2)(-)) production was profoundly inhibited by G?6976, a cPKC inhibitor, and dramatically increased by the DGK inhibitor, R59949. Ultrastructural analysis revealed that BIgG induced O(2)(-) production at the phagosome but not at the intracellular granules. We conclude that activation/accumulation of betaI PKC is involved in O(2)(-) production, and that O(2)(-) production is primarily initiated at the phagosomal cup/phagosome. This study also suggests that DGKbeta plays a prominent role in regulation of O(2)(-) production during FcgammaR-mediated phagocytosis. 相似文献
10.
Gomez-Godinez V Wu T Sherman AJ Lee CS Liaw LH Zhongsheng Y Yokomori K Berns MW 《Nucleic acids research》2010,38(22):e202
In this study the femtosecond near-IR and nanosecond green lasers are used to induce alterations in mitotic chromosomes. The subsequent double-strand break responses are studied. We show that both lasers are capable of creating comparable chromosomal alterations and that a phase paling observed within 1-2 s of laser exposure is associated with an alteration of chromatin as confirmed by serial section electron microscopy, DAPI, γH2AX and phospho-H3 staining. Additionally, the accumulation of dark material observed using phase contrast light microscopy (indicative of a change in refractive index of the chromatin) ~ 34 s post-laser exposure corresponds spatially to the accumulation of Nbs1, Ku and ubiquitin. This study demonstrates that chromosomes selectively altered in mitosis initiate the DNA damage response within 30 s and that the accumulation of proteins are visually represented by phase-dark material at the irradiation site, allowing us to determine the fate of the damage as cells enter G1. These results occur with two widely different laser systems, making this approach to study DNA damage responses in the mitotic phase generally available to many different labs. Additionally, we present a summary of most of the published laser studies on chromosomes in order to provide a general guide of the lasers and operating parameters used by other laboratories. 相似文献