全文获取类型
收费全文 | 654474篇 |
免费 | 72803篇 |
国内免费 | 525篇 |
专业分类
727802篇 |
出版年
2018年 | 6060篇 |
2017年 | 5737篇 |
2016年 | 8363篇 |
2015年 | 11072篇 |
2014年 | 12909篇 |
2013年 | 18348篇 |
2012年 | 20762篇 |
2011年 | 21486篇 |
2010年 | 14443篇 |
2009年 | 13138篇 |
2008年 | 18820篇 |
2007年 | 19470篇 |
2006年 | 17908篇 |
2005年 | 17452篇 |
2004年 | 17191篇 |
2003年 | 16480篇 |
2002年 | 15868篇 |
2001年 | 30838篇 |
2000年 | 30946篇 |
1999年 | 24425篇 |
1998年 | 8286篇 |
1997年 | 8631篇 |
1996年 | 8362篇 |
1995年 | 7574篇 |
1994年 | 7639篇 |
1993年 | 7375篇 |
1992年 | 19424篇 |
1991年 | 18683篇 |
1990年 | 18459篇 |
1989年 | 18117篇 |
1988年 | 16401篇 |
1987年 | 15794篇 |
1986年 | 14408篇 |
1985年 | 14479篇 |
1984年 | 11921篇 |
1983年 | 10325篇 |
1982年 | 7765篇 |
1981年 | 7147篇 |
1980年 | 6601篇 |
1979年 | 11157篇 |
1978年 | 8656篇 |
1977年 | 7946篇 |
1976年 | 7551篇 |
1975年 | 8270篇 |
1974年 | 8837篇 |
1973年 | 8774篇 |
1972年 | 7806篇 |
1971年 | 7246篇 |
1970年 | 6209篇 |
1969年 | 5902篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
112.
Conditions for breaking various medically important yeasts using glass beads, 30 ml Corex centrifuge tubes, and a Vortex mixer were determined. From 75–95% ofCandida hyphal cells and all species of yeasts exceptSporothrix schenckii were broken when 10 g of 0.45–0.50 mm glass beads, 50–300 mg of wet cells in 5 ml of buffer, and 90 s of vortexing were employed. Yeasts ofSporothrix schenckii broke more efficiently when 0.25–0.30 mm beads were used. 相似文献
113.
114.
115.
116.
117.
HbA1c is the most prevalent of the minor human hemoglobins. It is formed by the nonenzymatic addition of glucose to the alpha-amino group of the beta chain by an initial condensation reaction and a subsequent intermolecular Amadori rearrangement. We have developed a method of analysis which utilizes high performance liquid chromatography to follow the formation of HbA1c and greatly simplifies the determination of the kinetic parameters associated with this reaction. This has allowed us to study the effects of several Hb ligands, including the hydrogen ion, on the kinetics of this glycosylation reaction. Both the initial condensation reaction and the subsequent rearrangement are shown to exhibit acid catalysis, but the rate of the condensation step is limited by the extent of protonation of the alpha-amino group. The variation in kinetic parameters as a function of hydrogen ion concentration has allowed us to determine the probable reaction mechanism of HbA1c formation by comparison to previously reported model systems of Schiff base formation and Amadori rearrangement. The formation of pre-HbA1c from deoxy-Hb shows an increased forward rate when compared to oxy-Hb. The presence of physiologic concentrations of CO2 causes a proportional decrease in both k1 and k-1. 2,3-Diphosphoglycerate causes a significant increase in the keq of the formation reaction. The effects of CO and the substitution of L-glucose for D-glucose are not significant. 相似文献
118.
Modulation of the expression of interleukin 2 receptors of human thymocytes by recombinant interleukin 2 总被引:3,自引:0,他引:3
The effect of purified recombinant interleukin 2 on the expression of the receptors for interleukin 2 by human thymocytes was examined. Interleukin 2 augmented the expression of interleukin 2 receptors and interferon-gamma synthesis by thymocytes activated with concanavalin A, and it was required to maintain the growth of thymocytes in vitro and the expression of interleukin 2 receptors. The increase observed in the number of receptor bearing thymocytes and in the density of receptors due to interleukin 2 occurred within the first 2 days of culture. Dexamethasone inhibited the expression of interleukin 2 receptors, the synthesis of interferon-gamma, and the early proliferation and protein synthesis of lectin-activated thymocytes during the first 2 days of culture. The inhibitory effect of dexamethasone on the expression of interleukin 2 receptors and on the synthesis of interferon-gamma was reversed by interleukin 2, whereas its effect on proliferation and on protein synthesis during the first two days of culture was not reversed by interleukin 2. Interleukin 2 induced the proliferation of thymocytes in vitro, even in the absence of activation by lectin; however, the number of cells displaying receptors which could be detected with anti-Tac remained low throughout the first week of culture and interferon-gamma synthesis was not observed. Nonetheless, interleukin 2-induced proliferation was inhibited by anti-Tac on a dose dependent manner. The results of the study document that recombinant interleukin 2, like purified natural interleukin 2, is required for the expression of interleukin 2 receptors, for interferon-gamma synthesis, and for the growth of thymocytes in vitro. 相似文献
119.
Minh C. Nguyen Guang Huan Tu Kathryn E. Koprivnikar Melissa Gonzalez-Edick Karin U. Jooss Thomas C. Harding 《Cancer immunology, immunotherapy : CII》2010,59(9):1313-1323
A critical factor in clinical development of cancer immunotherapies is the identification of tumor-associated antigens that
may be related to immunotherapy potency. In this study, protein microarrays containing >8,000 human proteins were screened
with serum from prostate cancer patients (N = 13) before and after treatment with a granulocyte–macrophage colony-stimulating factor (GM-CSF)-secreting whole cell immunotherapy.
Thirty-three proteins were identified that displayed significantly elevated (P ≤ 0.05) signals in post-treatment samples, including three proteins that have previously been associated with prostate carcinogenesis,
galectin-8, T-cell alternative reading frame protein (TARP) and TNF-receptor-associated protein 1 (TRAP1). Expanded analysis
of antibody induction in metastatic, castration-resistant prostate cancer (mCRPC) patients (N = 92) from two phase 1/2 trials of prostate cancer immunotherapy, G-9803 and G-0010, indicated a significant (P = 0.03) association of TARP antibody induction and median survival time (MST). Antibody induction to TARP was also significantly
correlated (P = 0.036) with an increase in prostate-specific antigen doubling time (PSADT) in patients with a biochemical (PSA) recurrence
following prostatectomy or radiation therapy (N = 19) from in a previous phase 1/2 trial of prostate cancer immunotherapy, G-9802. RNA and protein encoding TARP and TRAP1
was up-regulated in prostate cancer tissue compared to matched normal controls. These preliminary findings suggest that antibody
induction to TARP may represent a possible biomarker for treatment response to GM-CSF secreting cellular immunotherapy in
prostate cancer patients and demonstrates the utility of using protein microarrays for the high-throughput screening of patient-derived
antibody responses. 相似文献
120.