全文获取类型
收费全文 | 4054篇 |
免费 | 238篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 218篇 |
妇产科学 | 86篇 |
基础医学 | 528篇 |
口腔科学 | 40篇 |
临床医学 | 285篇 |
内科学 | 810篇 |
皮肤病学 | 65篇 |
神经病学 | 249篇 |
特种医学 | 144篇 |
外科学 | 420篇 |
综合类 | 238篇 |
一般理论 | 5篇 |
预防医学 | 339篇 |
眼科学 | 85篇 |
药学 | 325篇 |
中国医学 | 73篇 |
肿瘤学 | 361篇 |
出版年
2023年 | 23篇 |
2022年 | 56篇 |
2021年 | 121篇 |
2020年 | 57篇 |
2019年 | 70篇 |
2018年 | 81篇 |
2017年 | 74篇 |
2016年 | 91篇 |
2015年 | 102篇 |
2014年 | 126篇 |
2013年 | 176篇 |
2012年 | 262篇 |
2011年 | 244篇 |
2010年 | 158篇 |
2009年 | 133篇 |
2008年 | 185篇 |
2007年 | 197篇 |
2006年 | 181篇 |
2005年 | 173篇 |
2004年 | 159篇 |
2003年 | 163篇 |
2002年 | 120篇 |
2001年 | 105篇 |
2000年 | 95篇 |
1999年 | 79篇 |
1998年 | 40篇 |
1997年 | 33篇 |
1996年 | 43篇 |
1995年 | 32篇 |
1994年 | 31篇 |
1993年 | 26篇 |
1992年 | 70篇 |
1991年 | 59篇 |
1990年 | 50篇 |
1989年 | 48篇 |
1988年 | 47篇 |
1987年 | 33篇 |
1986年 | 46篇 |
1985年 | 42篇 |
1984年 | 25篇 |
1983年 | 26篇 |
1979年 | 31篇 |
1977年 | 23篇 |
1976年 | 21篇 |
1975年 | 24篇 |
1973年 | 31篇 |
1972年 | 36篇 |
1971年 | 23篇 |
1970年 | 27篇 |
1968年 | 26篇 |
排序方式: 共有4304条查询结果,搜索用时 15 毫秒
31.
32.
Sensitivity of sandwich enzyme-linked immunosorbent assay for Cryptococcus neoformans polysaccharide antigen is dependent on the isotypes of the capture and detection antibodies. 下载免费PDF全文
Immunoglobulin M (IgM) and IgG1 monoclonal antibody isotype switch variants to Cryptococcus neoformans capsular polysaccharide were used to study the sensitivity of a double sandwich enzyme-linked immunosorbent assay (ELISA). The most sensitive ELISA configurations used IgG1 monoclonal antibody absorbed on polystyrene plates or IgM immobilized with goat antisera for antigen capture. 相似文献
33.
Differing role of dendritic cells and macrophages in the induction of delayed-type hypersensitivity responses to PPD. 下载免费PDF全文
In order to study the antigen-presenting cell (APC) requirements for the priming of delayed-type hypersensitivity (DTH), murine spleen cells were fractionated on bovine serum albumin gradients, pulsed in vitro with tuberculin, and then injected subcutaneously into normal mice. The other footpad was challenged with tuberculin between 24 hr and 7 days later and swelling was measured 2 hr and 18-24 hr after challenge. Optimum priming for 2-hr and 24-hr responses at 7 days was achieved by an injection of 5 X 10(5) tuberculin-pulsed intermediate-density Fc + ve cells. Time-course studies revealed that the 2-hr component could be elicited as early as 24 hr after injection of pulsed APC, while the 24-hr component became significant at 3 days. Elimination of T cells or B cells did not affect the response. Injection of pulsed APC into allogeneic mice primed the 2-hr but not the 24-hr component. Neither pulsed high-density cells (mostly T cells) nor pulsed dendritic cells (DC) primed mice for these responses. Failure to elicit DTH after injection of tuberculin-pulsed DC was due to their failure to prime the 2-hr component, which other authors have shown to be a prerequisite for the appearance of the later components. That DC did prime the MHC-restricted 24-hr component was demonstrated by protocols involving the use of both macrophages and DC as APC. 相似文献
34.
Suniti K. Mukherjee William H. Dantzler 《Pflügers Archiv : European journal of physiology》1985,403(1):35-40
Effects of an inhibitor of membrane anion-exchange transport processes, 4-acetamido-4-isothiocyano-2,2-disulfonic stilbene (SITS), on urate transport by isolated, perfused snake (Thamnophis spp.) proximal renal tubules were studied. SITS (10–4 mol/l) in the luminal perfusate had absolutely no effect on net urate secretion (J
urate
net
) or on net fluid absorption (J
v). This observation is compatible with other data that give no support to the concept of a mediated transport step for urate from the cells to the lumen. SITS (10–4 mol/l) in the bathing medium reversibly inhibitedJ
urate
net
without affectingJ
v. At the time of maximum inhibition ofJ
urate
net
, the concentration of urate in the cell water was increased and the apparent permeability of the luminal membrane to urate was decreased, but the urate efflux across the peritubular membrane and the apparent permeability of the peritubular membrane to urate were unchanged. There was no evidence of significant intracellular binding or trapping of urate. Although an increase in the initial rate of urate transport into the cells across the peritubular membrane could not be demonstrated conclusively in nonperfused tubules, the results still suggest that SITS in the bathing medium may inhibitJ
urate
net
by inhibiting urate movement from the cells to the lumen while actually enhancing transport from the bathing medium into the cells. 相似文献
35.
A microtiter plate ELISA with semipurified human nerve sonicate antigen(s) (NA) was used to screen the sera of leprosy patients. High titers of IgG and low titers of IgM classes of antineural antibodies directed to peripheral nerve antigens were detected in LL, BL, BB, BT, and TT categories of leprosy. In the Western blot, leprosy sera recognized 50- to 55-, 85- and 108-kDa molecular weight protein bands of NA. The identity of these protein bands immunoreactive with leprosy sera was checked with a panel of commercially available antibodies to known neural proteins. The 50- to 55-kDa band reacted with anti-S100 and anti-glial fibrillary acidic protein antibodies while 85 and 108 kDa could not be identified. Whole immunoglobulins isolated from leprosy sera with high titers of antineural antibodies induced cytotoxicity of the cultured glial cell line in the presence of complement. 相似文献
36.
Induction of delayed-type hypersensitivity responses to PPD: dendritic cells in synergy with 5-hydroxytryptamine can substitute for macrophages. 下载免费PDF全文
We describe the use of 5-hydroxytryptamine (5HT) as an adjuvant in the induction of the delayed-type hypersensitivity (DTH) response to purified protein derivative (PPD). Based upon our previous studies with antigen-pulsed macrophages (M phi), we have shown that both the Day 2 early (2 hr) reaction and the Day 3 (24 hr) reaction are augmented if 5HT is incorporated into the priming injection. Furthermore, we have confirmed that in contrast to M phi, antigen-pulsed dendritic cells (DC) fail to prime the early (2 hr) component of DTH. However, DC do prime the early response if injected along with 5HT. A peripheral 5HT antagonist, ICS 205-930, inhibits both the M phi-mediated and the 5HT/DC-primed reactions. These findings support the hypothesis that DTH reactions require a cascade of both inflammatory and immunological signals, and that in mice vascular permeability mediated via 5HT is important in the early phase of the reaction. 相似文献
37.
Pelin Sahlén Rapolas Spalinskas Samina Asad Kunal Das Mahapatra Pontus Höjer Anandashankar Anil Jesper Eisfeldt Ankit Srivastava Pernilla Nikamo Anaya Mukherjee Kyu-Han Kim Otto Bergman Mona Ståhle Enikö Sonkoly Andor Pivarcsi Carl-Fredrik Wahlgren Magnus Nordenskjöld Fulya Taylan Isabel Tapia-Páez 《The Journal of allergy and clinical immunology》2021,147(5):1742-1752
38.
39.
Chattopadhyay P Pakstis AJ Mukherjee N Iyengar S Odunsi A Okonofua F Bonne-Tamir B Speed W Kidd JR Kidd KK 《European journal of human genetics : EJHG》2003,11(10):760-769
We have constructed haplotypes based on normal variation at six polymorphic sites-five single nucleotide polymorphisms (SNPs) and one short tandem repeat polymorphism (STRP)-at the RET locus for samples of normal individuals from 32 populations distributed across the major continental regions of the world. The haplotyped system spans 41.6 kilobases and encompasses most of the coding region of the gene. All of the markers are polymorphic in all regions of the world and in most individual populations. Expected heterozygosities for the six-site haplotypes range from 82 to 94% for all populations studied except for two Amerindian groups from the Amazon basin at 61 and 76%. Individual populations had from four to eight haplotypes with frequencies exceeding 5%. In general, African, southwest Asian and European groups have the highest numbers of total and of commonly occurring haplotypes; the lowest numbers are observed in Amerindian populations. Overall linkage disequilibrium (LD) for the five SNP sites was very significant (P=0.001) for all the non-African populations, but significant at that level for only one of the seven African populations. In general, the permutation-based xi coefficient that quantifies overall LD tends to increase the farther the population is from Africa, but variability of this measure of LD is often large within geographic regions. Pairwise LD measures among the SNPs also show considerable variation among populations. Association of STRP alleles with the SNP-defined background haplotypes is generally higher outside of Africa than in Africa, but is highly variable. 相似文献
40.
Nursling rats were given a lethal dose of corynetoxin and the sequential morphological alterations in the cerebellum were examined at daily intervals up to 3 days post-inoculation. Ultrastructural changes were those of cerebral vascular damage, which was usually focal in affected endothelial cells, and resulted in vascular stasis or thrombosis. These changes ultimately constituted a failure of perfusion in focal areas of brain parenchyma supplied by these vessels, resulting in necrosis. 相似文献