全文获取类型
收费全文 | 18362篇 |
免费 | 1937篇 |
国内免费 | 781篇 |
专业分类
耳鼻咽喉 | 180篇 |
儿科学 | 376篇 |
妇产科学 | 460篇 |
基础医学 | 4132篇 |
口腔科学 | 412篇 |
临床医学 | 1639篇 |
内科学 | 2799篇 |
皮肤病学 | 377篇 |
神经病学 | 978篇 |
特种医学 | 386篇 |
外国民族医学 | 9篇 |
外科学 | 1200篇 |
综合类 | 2842篇 |
现状与发展 | 4篇 |
预防医学 | 964篇 |
眼科学 | 376篇 |
药学 | 1850篇 |
6篇 | |
中国医学 | 802篇 |
肿瘤学 | 1288篇 |
出版年
2024年 | 24篇 |
2023年 | 195篇 |
2022年 | 370篇 |
2021年 | 590篇 |
2020年 | 606篇 |
2019年 | 618篇 |
2018年 | 637篇 |
2017年 | 722篇 |
2016年 | 763篇 |
2015年 | 766篇 |
2014年 | 1195篇 |
2013年 | 1439篇 |
2012年 | 1032篇 |
2011年 | 1200篇 |
2010年 | 941篇 |
2009年 | 871篇 |
2008年 | 902篇 |
2007年 | 882篇 |
2006年 | 842篇 |
2005年 | 824篇 |
2004年 | 727篇 |
2003年 | 654篇 |
2002年 | 508篇 |
2001年 | 479篇 |
2000年 | 454篇 |
1999年 | 328篇 |
1998年 | 316篇 |
1997年 | 295篇 |
1996年 | 248篇 |
1995年 | 224篇 |
1994年 | 229篇 |
1993年 | 170篇 |
1992年 | 117篇 |
1991年 | 106篇 |
1990年 | 99篇 |
1989年 | 87篇 |
1988年 | 71篇 |
1987年 | 71篇 |
1986年 | 70篇 |
1985年 | 92篇 |
1984年 | 57篇 |
1983年 | 46篇 |
1982年 | 43篇 |
1981年 | 35篇 |
1980年 | 23篇 |
1979年 | 23篇 |
1978年 | 18篇 |
1977年 | 18篇 |
1976年 | 18篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Slotwiński R Olszewski WL Chaber A Slodkowski M Zaleska M Krasnodebski IW 《Journal of clinical immunology》2002,22(5):289-296
The clinical implications of increased cytokine levels after major surgery remain unclear. In this study, systemic concentration of a spectrum of cytokines, including interleukins IL-6, IL-8, IL-10, IL-1ra, and soluble tumor necrosis factor receptor-I (sTNF-RI) was examined in patients with and without postoperative septic complications following colorectal surgery. Although there were no significant changes in IL-1, TNF-, and IL-8 serum levels during the observation period, there was a significant rise in IL-6, IL-1ra, and sTNF-RI concentrations in the entire group of patients between postoperative day 1 and 14. There were no differences between the group without and with local complications when IL-6, IL-1ra, and IL-10 were examined. The serum levels of sTNF-RI, IL-1ra, and IL-6 were found to be sensitive indicators of the pro- and anti-inflammatory response to the surgical trauma, but only sTNF-RI turned out to be a sensitive early marker of local septic postoperative complications in patients with colorectal carcinoma. 相似文献
32.
Kinetics of the phenotype and function of murine peritoneal macrophages following acute inflammation 总被引:2,自引:0,他引:2
Wu Q Feng Y Yang Y Jingliu Zhou W He P Zhou R Li X Zou J 《Cellular & molecular immunology》2004,1(1):57-62
This study was undertaken to have a better understand for the process and the underlying mechanisms to limitmacrophage activation and population of activated macrophages.A comprehensive kinetics of cytokineproduction was performed in murine peritoneal macrophages recovered from Balb/c mice at various timeduring the course of an intraperitoneal injection with thioglycollate (TG).The expression of cell surfacemolecules such as MHC-Ⅰ,MHC-Ⅱ,B7-1 and B7-2 of these macrophages were also determined by flowcytometry.The present findings of our research suggested that the population of activated macrophages and theactivation of macrophages (including cytokines production and expression of cell surface functional molecules)were strictly controlled during inflammation process.This is one of the important mechanisms to retain the hosthomeostasis.Cellular & Molecular Immunology.2004;1(1):57-62. 相似文献
33.
Expression of the PD-1 antigen on the surface of stimulated mouse T and B lymphocytes 总被引:28,自引:4,他引:28
Agata Yasutoshi; Kawasaki Akemi; Nishimura Hiroyuki; Ishida Yasumasa; Tsubat Takeshi; Yagita Hideo; Honjo Tasuku 《International immunology》1996,8(5):765-772
A mAb J43 has been produced against the product of the mousePD-1 gene, a member of the Ig gene superfamily, which was previouslyisolated from an apoptosis-induced T cell hybridoma (2B4.11)by using subtractive hybridization. Analyses by flow cytometryand immunoprecipitation using the J43 mAb revealed that thePD-1 gene product is a 50–55 kDa membrane protein expressedon the cell surface of several PD-1 cDNA transfectants and 2B4.11cells. Since the molecular weight calculated from the aminoacid sequence is 29,310, the PD-1 protein appears to be heavilyglycosylated. Normal murine lymphoid tissues such as thymus,spleen, lymph node and bone marrow contained very small numbersof PD-1+ cells. However, a significant PD-1+ population appearedin the thymocytes as well as T cells in spleen and lymph nodesby the in vivo anti-CD3 mAb treatment. Furthermore, the PD-1antigen expression was strongly induced in distinct subsetsof thymocytes and spleen T cells by in vitro stimulation witheither anti-CD3 mAb or concanavalin A (Con A) which could leadT cells to both activation and cell death. Similarly, PD-1 expressionwas induced on spleen B cells by in vitro stimulation with anti-IgMantibody. By contrast, PD-1 was not significantly expressedon lymphocytes by treatment with growth factor deprivation,dexamethasone or lipopolysaccharide. These results suggest thatthe expression of the PD-1 antigen is tightly regulated andinduced by signal transduction through the antigen receptorand do not exclude the possibility that the PD-1 antigen mayplay a role in clonal selection of lymphocytes although PD-1expression is not required for the common pathway of apoptosis. 相似文献
34.
de Groot J Kruijt L Scholten JW Boersma WJ Buist WG Engel B van Reenen CG 《Immunology》2005,115(4):495-505
The capacity of farm animals to produce cytokines could be an important determinant of robustness and health. From research in rodents and humans it appears that the production and the balance of T helper 1 (Th1) and T helper 2 (Th2)-type cytokines influences susceptibility to autoimmune and infectious diseases. It is known that pigs show a large variation in many immune response parameters. So far the extent of individual variation in the production of Th1- and Th2-type cytokines in commercial outbred pigs has not been reported. In the current experiment we determined mRNA expression, as well as protein production of cytokines in 32 pigs from eight litters. From each litter two male and two female pigs were tested at 2, 5 and 8 weeks of age. Two Th1-type cytokines, interleukin (IL)-2 and interferon (IFN)-gamma, and two Th2-type cytokines, IL-4 and IL-10, were measured after phytohaemagglutinin (PHA)-stimulation of blood mononuclear cells. Cytokine production and the Th1/Th2-ratio were highly variable. The variation in cytokine protein production was moderately consistent across ages, i.e. pigs that produced high levels of cytokine at 2 weeks of age tended to do so as well at 5 and 8 weeks of age. Cytokine production tended to increase with age, and gilts and boars differed in their IL-2/IL-4 ratio. Unexpectedly, age, gender and litter effects often differed for mRNA and protein production data. We hypothesize that cytokine production is a consistent trait in pigs, especially at the protein production level. Future investigations in more animals and across a wider age range are necessary. 相似文献
35.
Uzi Gafter Benjamin Sredni Jacob Segal Yona Kalechman 《Journal of clinical immunology》1997,17(5):408-419
Spontaneous recurrent abortion (SRA) has been treated by means of immunization with paternal or third-party white blood cells, yet the immunological basis for SRA and for the role of immunization protocols in pregnancy outcome remains controversial. To elucidate this question, nine women with SRA were immunized with paternal mononuclear cells and studied before and 2 weeks after immunization. Seven women who became pregnant gave birth to live newborns. Secretion of the T helper 1 cytokines IL-2 and interferon- by patients' mononuclear cells decreased, while production of IL-10 increased. The levels of natural killer and lymphokine-activated killer cell-mediated cytotoxicity were markedly decreased. Monocyte functions such as secretion of IL-l, tumor necrosis factor a, IL-6, and cytotoxic activity decreased concurrently with elevations in IL-10 and transforming growth factor secretion. Production of IL-12, a pivotal regulatory cytokine, decreased. Furthermore, B7/1 expression on patients' mononuclear cells was downregulated. This resulted in a decrease in monocyte costimulatory activity of purified T cells with soluble anti-CD3, paralleled by a decline in allogeneic proliferative responses. These results suggest that the improved pregnancy success rate in women with SRA following immunization may be partly related to suppression of cell-mediated immunity and monocyte and natural killer cell activity. 相似文献
36.
Depressed patients show a reduction of natural killer (NK) cell activity which may be associated with specific depressive symptoms. The present study demonstrated that sleep disturbance and retardation, but not other depressive symptoms, were negatively correlated with NK activity in 38 depressed patients. Specific behavioral changes in depression such as sleep disturbance and retardation were found to predict 16% of the variance of cytotoxicity levels in depression. 相似文献
37.
Comparison of different metrics, using three large samples of haplotypes from different populations, demonstrates that rho is the most efficient measure of association between pairs of single nucleotide polymorphisms (SNPs). Pairwise data can be modeled, using composite likelihood, to describe the decline in linkage disequilibrium with distance (the Malecot model). The evidence from more isolated populations (Finland, Sardinia) suggests that linkage disequilibrium extends to 427-893 kb but, even in samples representative of large heterogeneous populations, such as CEPH, the extent is 385 kb or greater. This suggests that isolated populations are not essential for linkage disequilibrium mapping of common diseases with SNPs. The in parameter of the Malecot model (recombination and time), evaluated at each SNP, indicates regions of the genome with extensive and less extensive disequilibrium (low and high values of in respectively). When plotted against the physical map, the regions with extensive and less extensive linkage disequilibrium may correspond to recombination cold and hot spots. This is discussed in relation to the Xq25 cytogenetic band and the HFE gene region. 相似文献
38.
慢性乙肝患者杀伤性免疫细胞功能的研究 总被引:8,自引:0,他引:8
通过对44例病毒性肝炎患者T细胞亚群,NK细胞活性与LAK细胞活性的观察,探讨了在慢性乙型肝炎病毒复制与非复制状态下的杀伤性细胞活性。结果表明:在乙肝病毒的高复制状态下,CD8^+细胞数增加,CD4^+/CD8^+比例显著下降;NK细胞活性与LAK细胞活性也明显低下,且在HBeAg与HBVDNA阳性组中,NK活性与LAK活性的改变与HBeAg的P/N值变化呈显著负相关,而NK活性与LAK活性变化则 相似文献
39.
40.
K. Kobayashi T. Suda K. Nan-ya N. Sakaguchi S. Sakaguchi I. Miki 《Inflammation research》2006,55(8):335-341
Objective SKG mice have a point mutation of the zeta-associated protein of 70 kD (ZAP-70) and spontaneously develop a severe polyarthritis
in the conventional condition, whereas they are healthy under the specific pathogen free (SPF) condition. The purpose of this
study was to investigate the cytokine production from splenocytes in SKG mice developing arthritis under the SPF condition.
Material SKG and BALB/c mice were intraperitoneally injected with zymosan A under the SPF condition. Spleen was isolated 1, 2 or 8 weeks
after the intraperitoneal injection of saline or zymosan A. Splenocytes were cultured with concanavalin A. Cytokine production
and proliferation were measured 48 and 72 h after the culture.
Results An intraperitoneal injection of zymosan A induced severe polyarthritis with increased levels of rheumatoid factor and interleukin
6 (IL-6) only in SKG mice. Splenocytes from SKG mice did not proliferate well maybe because of less productivity of IL-2.
The IL-4 production from splenocytes of SKG mice was higher, while interferon-γ production was lower than those of BALB/c
mice. An injection of zymosan A reduced the IL-4 production only in SKG mice.
Conclusions SKG mice do not develop arthritis under the SPF condition possibly because of a low proliferative activity of T cells and
Th2-predominance.
Received 27 December 2005; returned for revision 7 February 2006; accepted by A. Falus 10 March 2006 相似文献