首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   11121篇
  免费   861篇
  国内免费   67篇
耳鼻咽喉   111篇
儿科学   433篇
妇产科学   214篇
基础医学   1470篇
口腔科学   460篇
临床医学   1169篇
内科学   2150篇
皮肤病学   237篇
神经病学   893篇
特种医学   582篇
外科学   1753篇
综合类   320篇
一般理论   6篇
预防医学   793篇
眼科学   131篇
药学   680篇
  2篇
中国医学   55篇
肿瘤学   590篇
  2023年   131篇
  2022年   214篇
  2021年   421篇
  2020年   254篇
  2019年   289篇
  2018年   358篇
  2017年   241篇
  2016年   253篇
  2015年   273篇
  2014年   380篇
  2013年   453篇
  2012年   668篇
  2011年   642篇
  2010年   390篇
  2009年   363篇
  2008年   465篇
  2007年   463篇
  2006年   434篇
  2005年   416篇
  2004年   347篇
  2003年   349篇
  2002年   321篇
  2001年   273篇
  2000年   247篇
  1999年   213篇
  1998年   171篇
  1997年   139篇
  1996年   135篇
  1995年   119篇
  1994年   93篇
  1993年   102篇
  1992年   138篇
  1991年   144篇
  1990年   129篇
  1989年   154篇
  1988年   143篇
  1987年   145篇
  1986年   122篇
  1985年   124篇
  1984年   80篇
  1983年   77篇
  1982年   48篇
  1980年   58篇
  1979年   67篇
  1978年   55篇
  1976年   45篇
  1974年   55篇
  1972年   57篇
  1971年   60篇
  1970年   44篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The oligosaccharide moiety of human, porcine and bovine zonaepellucidae was studied with lectins and monoclonal antibodiesspecific for tri- or tetra-saccharidic epitopes containing atleast one terminal -L-fucose. Animal eggs were collected fromfollicular aspirates, human eggs were collected from in-vitrofertilization and embryo transfer programmes and pooled intosix groups. By direct immunofluorescence, the lectins reactivitywas detected for the animal or the human zonae pools in thesame way. Reactivity of Aleuria aurantia lectin demonstratedthe presence of –L-fucose terminal residues in the zonaefrom the three species studied. By indirect immunofluorescence,the 2–25 antibody reactivity was detected in every poolof human zonae whereas there was no evidence of any antibodyreactivity on animal zonae. Using an anti-Lewis-b blood groupantibody (2–25), we observed expression of this antigenas an intrinsic component of the human zona pellucida, independentlyof patients'Lewis red blood cell phenotypes. Antibody 2–25inhibited the sperm–atozoa-zona binding in a hemizonaassay, suggesting that this fucose-containing antigen couldbe part of a sperm-zona receptor.  相似文献   
72.
Twelve mycobacterial antigens were compared for induction of gamma interferon (IFN-gamma) secretion by human blood mononuclear cells of patients with leprosy. Fractionated Mycobacterium leprae antigens containing cell wall proteins or cytosolic and membrane proteins induced good IFN-gamma responses in tuberculoid leprosy patients. Lipoarabinomannan from M. tuberculosis Erdman and M. leprae mycolylarabinogalactan peptidoglycan were the poorest IFN-gamma inducers.  相似文献   
73.
Intramuscular sensitization of hamsters with several forms of respiratory syncytial virus (RSv) caused proliferation of lung epithelium. In contrast, intranasal injection of live virus rarely resulted in this phenomenon. A correlation existed between proliferation of lung epithelium and presence of complement-fixing antibody, but not between lung disease and delayed skin reactions. Complement-fixing antibody to RSv was found to be independent of the influence of the thymus.  相似文献   
74.
A common feature of hematopoietic activating immunoreceptors resides in their association at the cell surface with transmembrane signaling adaptors. Several adaptors, such as the CD3 molecules, FcRgamma and KARAP/DAP12, harbor intracytoplasmic immunoreceptor tyrosine-based activation motifs (ITAM) that activate Syk-family protein tyrosine kinases. In contrast, another transmembrane adaptor, DAP10, bears a YxxM motif that delivers signals by activation of lipid kinase pathways. We show here that the human signal-regulatory protein SIRPbeta1 can associate with both DAP10 and KARAP/DAP12 in a model of RBL-2H3 cell transfectants. In association with KARAP/DAP12, SIRPbeta1 complexes are capable of inducing serotonin release and tumor necrosis factor (TNF) secretion. By contrast,in the absence of KARAP/DAP12, engagement of SIRPbeta1:DAP10 complexes does not lead to detectable serotonin release or TNF secretion by RBL-2H3 transfectants. However, triggering of SIRPbeta1:DAP10 complexes co-stimulates RBL-2H3 effector function induced by sub-optimal stimulation of the endogenous FcepsilonRI complex. Therefore, we report here a cellular model in which the association of a cell surface receptor with various signaling adaptors dictates the co-stimulatory or the direct stimulatory properties of the complex.  相似文献   
75.
A case of neonatal alloimmune thrombocytopenia due to fetomaternal incompatibility against the platelet specific antigen PlA2 (Zwb) is described. Anti-PlA2 antibodies were present in the maternal serum together with anti-HLA antibodies. Initial identification of the platelet-specific antibodies was achieved by using chloroquine-treated PlA1(+) and PlA1(-) platelets. Antibody specificity was later confirmed using a panel of platelets of known phenotype.  相似文献   
76.
A self-setting single-component calcium phosphate cement   总被引:6,自引:0,他引:6  
Zoulgami M  Lucas A  Briard P  Gaudé J 《Biomaterials》2001,22(13):1933-1937
Following an original synthesis route, we have prepared a single-component calcium phosphate apatite-like powder which settles and hardens when mixed with deionized water in an approximative 1.2 g:1 ml ratio. This paper describes the first physico-chemical studies and characterizations of the material. Observations of its in vitro behavior show a slight volume contraction and toxicity against fibroblasts bone marrow cells on disks of compacted powder. It is suggested that after an improvement of the powder characters such as grain size, and the choice of another hardening liquid, to name a few, this material should be a potential--or an ingredient of--bone cement.  相似文献   
77.
78.
79.
Insemination with donor spermatozoa is an integral part of infertility treatment. For the last 3 years in our unit, intrauterine insemination with donor spermatozoa (IUID) has been used in preference to vaginal insemination. In this retrospective study, patients were offered an initial course of five single intrauterine inseminations with cryopreserved donor spermatozoa and treatment was then reviewed. A total of 389 patients received 1465 inseminations. In all, 1119 cycles were monitored using luteinizing hormone serum analyses and 346 cycles using the urine home test kits. The clinical pregnancy rate per insemination for the cycles monitored by the serum assay was 18.0% (202/1119) compared with the urine cycles (13.7%, 46/346) (P <05). The pregnancy loss rate was not significantly different (14.4%, 29/202 and 21.7%, 10/46) (serum and urine cycles respectively). The viable clinical pregnancy rate was significantly higher (P <03) for the serum cycles than for the cycles using the urinary monitoring (15.5%, 173/1119 and 10.4%, 36/346 respectively). The cycles monitored by serum assay had a significantly higher cumulative viable clinical pregnancy rate (P <0001) of 70.2% after nine inseminations compared with the urine monitored cycles of 54.8%. The majority of patients opted for the serum cycles, with a minority self-selecting the urine cycles mainly for travelling convenience. The explanation for the significant differences between the viable clinical pregnancy rates per insemination and the cumulative viable clinical pregnancy rates may be due to the sensitivity of the urine home test kit or the patients' interpretation of the result.   相似文献   
80.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号