全文获取类型
收费全文 | 12292篇 |
免费 | 857篇 |
国内免费 | 53篇 |
专业分类
耳鼻咽喉 | 135篇 |
儿科学 | 368篇 |
妇产科学 | 285篇 |
基础医学 | 1439篇 |
口腔科学 | 203篇 |
临床医学 | 1425篇 |
内科学 | 2609篇 |
皮肤病学 | 133篇 |
神经病学 | 1003篇 |
特种医学 | 589篇 |
外国民族医学 | 1篇 |
外科学 | 2043篇 |
综合类 | 129篇 |
一般理论 | 11篇 |
预防医学 | 1058篇 |
眼科学 | 214篇 |
药学 | 617篇 |
中国医学 | 11篇 |
肿瘤学 | 929篇 |
出版年
2023年 | 116篇 |
2022年 | 255篇 |
2021年 | 552篇 |
2020年 | 278篇 |
2019年 | 410篇 |
2018年 | 474篇 |
2017年 | 345篇 |
2016年 | 363篇 |
2015年 | 451篇 |
2014年 | 608篇 |
2013年 | 660篇 |
2012年 | 1036篇 |
2011年 | 1084篇 |
2010年 | 573篇 |
2009年 | 443篇 |
2008年 | 782篇 |
2007年 | 742篇 |
2006年 | 714篇 |
2005年 | 635篇 |
2004年 | 523篇 |
2003年 | 495篇 |
2002年 | 432篇 |
2001年 | 62篇 |
2000年 | 45篇 |
1999年 | 58篇 |
1998年 | 88篇 |
1997年 | 81篇 |
1996年 | 67篇 |
1995年 | 56篇 |
1994年 | 54篇 |
1993年 | 62篇 |
1992年 | 42篇 |
1991年 | 37篇 |
1990年 | 33篇 |
1989年 | 44篇 |
1988年 | 37篇 |
1987年 | 24篇 |
1986年 | 28篇 |
1985年 | 27篇 |
1984年 | 34篇 |
1983年 | 23篇 |
1982年 | 34篇 |
1981年 | 24篇 |
1980年 | 25篇 |
1978年 | 18篇 |
1977年 | 18篇 |
1976年 | 16篇 |
1975年 | 23篇 |
1974年 | 13篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Sanchez AA Johnston DA Myers C Edwards JE Mitchell AP Filler SG 《Infection and immunity》2004,72(1):598-601
Candida albicans must penetrate the endothelial cell lining of the vasculature to invade the deep tissues during a hematogenously disseminated infection. We compared 27 C. albicans mutants with their wild-type parent for their capacity to damage endothelial cells in vitro and cause a lethal infection in mice following tail vein inoculation. Of 10 mutants with significantly impaired capacity to damage endothelial cells, all had attenuated virulence. Therefore, the endothelial cell damage assay can be used as a screen to identify some virulence factors relevant to hematogenously disseminated candidiasis. 相似文献
52.
Brandon C McKinney Aaron W Grossman Nicholas M Elisseou William T Greenough 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2005,(1):98-102
Fragile X syndrome (FXS) is the most common form of inherited mental retardation. Observed neuropathologies associated with FXS include abnormal length, morphology, and density of dendritic spines, reported in individuals with FXS and in Fmr1 knockout (KO) mice, an animal model of FXS. To date, however, these neuropathologies have been studied in Fmr1 KO mice bred in a FVB background (a strain with genetic mutations that complicate interpretation of results) and findings have been inconsistent. Here, Golgi-Cox impregnation was used to investigate length, morphology, and density of dendritic spines on layer V pyramidal neurons in visual cortices of Fmr1 KO and wildtype (WT) mice bred in a C57BL/6 background. We report that spine abnormalities in these animals parallel abnormalities reported in humans with FXS, perhaps to a greater degree than KO mice bred in an FVB background. Specifically, Fmr1 KO mice bred in a C57BL/6 background exhibited significantly more longer dendritic spines and fewer shorter spines, as well as more spines with immature-appearing morphology and fewer with mature-appearing morphology than WT littermates. Spine length abnormalities were demonstrated to be largely independent of spine morphology abnormalities, as the length phenotype was observed in KOs even within a morphological category. Fmr1 KO mice also had a greater overall spine density than WTs. These findings provide powerful support for the essence of the dendritic spine abnormalities in the absence of FMRP, now found to be largely consistent with human data across two mouse backgrounds. 相似文献
53.
Germinal center and activated b-cell profiles separate Burkitt lymphoma and diffuse large B-cell lymphoma in AIDS and non-AIDS cases 总被引:1,自引:0,他引:1
Gormley RP Madan R Dulau AE Xu D Tamas EF Bhattacharyya PK LeValley A Xue X Kumar P Sparano J Ramesh KH Pulijaal V Cannizzaro L Walsh D Ioachim HL Ratech H 《American journal of clinical pathology》2005,124(5):790-798
Morphologic features of Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) overlap. No single phenotypic marker or molecular abnormality is pathognomonic. We tested a panel of 8 germinal center (GC) and activated B-cell (ABC) markers for their ability to separate BL and DLBCL. We diagnosed 16 BL and 39 DLBCL cases from 21 patients with AIDS and 34 without AIDS based on traditional morphologic criteria, Ki-67 proliferative index, and c-myc rearrangement (fluorescence in situ hybridization). After immunohistochemically staining tissue microarrays of BL and DLBCL for markers of GC (bcl-6, CD10, cyclin H) and ABC (MUM1, CD138, PAK1, CD44, bcl-2), we scored each case for the percentage of positive cells. Hierarchical clustering yielded 2 major clusters significantly associated with morphologic diagnosis (P < .001). For comparison, we plotted the sum of the GC scores and ABC scores for each case as x and y data points. This revealed a high-GC/low-ABC group and a low-GC/high-ABC group that were associated significantly with morphologic diagnosis (P < .001). Protein expression of multiple GC and ABC markers can separate BL and DLBCL. 相似文献
54.
Specificity of blebbistatin, an inhibitor of myosin II 总被引:10,自引:0,他引:10
Limouze J Straight AF Mitchison T Sellers JR 《Journal of muscle research and cell motility》2004,25(4-5):337-341
Blebbistatin is a small molecule inhibitor discovered in a screen for inhibitors of nonmuscle myosin IIA. We have examined
the specificity and potency of the drug by assaying its effects on the actin-activated MgATPase assay of diverse members of
the myosin superfamily. Blebbistatin potently inhibits several striated muscle myosins as well as vertebrate nonmuscle myosin
IIA and IIB with IC50 values ranging from 0.5 to 5 μM. Interestingly, smooth muscle which is highly homologous to vertebrate nonmuscle myosin is
only poorly inhibited (IC50=80 μM). The drug potently inhibits Dictyostelium myosin II, but poorly inhibits Acanthamoeba myosin II. Blebbistatin did not inhibit representative myosin superfamily members from classes I, V, and X.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
55.
CD39 activity correlates with stage and inhibits platelet reactivity in chronic lymphocytic leukemia
Dianne Pulte Kim E Olson M Johan Broekman Naziba Islam Harold S Ballard Richard R Furman Ashley E Olson Aaron J Marcus 《Journal of translational medicine》2007,5(1):23
Background
Chronic lymphocytic leukemia (CLL) is characterized by accumulation of mature appearing lymphocytes and is rarely complicated by thrombosis. One possible explanation for the paucity of thrombotic events in these patients may be the presence of the ecto-nucleotidase CD39/NTDPase-1 on the surface of the malignant cells in CLL. CD39 is the major promoter of platelet inhibition in vivo via its metabolism of ADP to AMP. We hypothesize that if CD39 is observed on CLL cells, then patients with CLL may be relatively protected against platelet aggregation and recruitment and that CD39 may have other effects on CLL, including modulation of the disease, via its metabolism of ATP. 相似文献56.
Ten members of two families with D/G translocation, three members of a family with D/D translocation, and one patient with non-familial and one with apparently non-familial D/D translocation were examined. The trdnslocation chromosomes were identified by SH-thymidine labeling and autoradio-graphy as 14q21q and 13q14q, respectively. These findings support the hypothesis of nonrandomness of D group chromosomes involved in centric-fusion translocation. The importance of the identification of Dgroup chromosomes involved in centriofusion translocation in relation to genetic counseling is discussed. 相似文献
57.
The coccidium Sarcocystis singaporensis (Apicomplexa: Sarcocystidae) is a cyst-forming parasite with potential as a biological agent for the control of wild populations of rodents in non-native environments. Phylogenetic analysis based on the ssrDNA supports S. singaporensisisolates as a sister species to sarcosporidians transmitted between snakes and rodents but an association with the carnivore-ruminant Sarcocystis spp. could not be rejected by likelihood ratio tests. Four complete and six partial ssrDNA sequences representing this species are monophyletic in any tree reconstruction method; however, they possess very high pairwise distances of up to 0.053. The obtained sequences suggest the probable existence of at least two divergent paralogous ssrDNAs. Moreover, our results support the co-evolution of lsrDNA and ssrDNA in S. singaporensis. The utility of coccidian lsrDNA and ssrDNA for evolutionary studies and their abundance in the primary nucleotide databases is discussed. 相似文献
58.
The authors investigated whether corticotropin-releasing factor (CRF) within the central nucleus of the amygdala (CeA) and bed nucleus of the stria terminalis (BNST) is a critical component of the neural circuitry mediating conditioned defeat. In this model, hamsters that have experienced social defeat subsequently display only submissive-defensive agonistic behavior instead of territorial aggression. Conditioned defeat was significantly reduced following infusion of the CRF receptor antagonist D-Phe CRF((12-41)) into the BNST but not into the CeA. In another experiment, hamsters given unilateral lesions of the CeA and infusions of D-Phe CRF((12-41)) into the contralateral BNST displayed significantly less submissive behavior than did controls. These data suggest that CRF acts within a neural circuit that includes the amygdala and the BNST to modulate agonistic behavior following social defeat. 相似文献
59.
Growth of human connective tissue progenitor cells (CTPs) was characterized on smooth and microtextured polydimethylsiloxane (PDMS) surfaces. Human bone marrow derived cells were cultured for nine days under conditions promoting osteoblastic differentiation on Smooth PDMS and PDMS Channel microtextures (11 m high, 45 m wide channels, and separated by 5 m wide ridges). Glass tissue culture dish surfaces were used as controls. Cell numbers per colony, cell density within colonies, alignment of cells, area of colonies, and colony shapes were determined as a function of substrate surface topography. An alkaline phosphatase stain was used as a marker for osteoblastic phenotype. CTPs attached, proliferated, and differentiated on all surfaces with cell process lengths of up to 80 m. Cells on the Smooth PDMS and control surfaces spread and proliferated as colonies in proximity to other cells and migrated in random directions creating colonies that covered significantly larger areas (0.96 and 1.05 mm2, respectively) than colonies formed on PDMS Channel textures (0.64 mm2). In contrast, cells on PDMS Channel textures spread, proliferated, aligned along the channel axis, and created colonies that were more dense, and with lengths of longest colony axes that were significantly longer (3252 m) than those on the Smooth PDMS (1265 m) and control surfaces (1319 m). Cells on PDMS Channel textures were aligned at an angle of 14.44° relative to the channel axis, and the resulting colonies exhibited a significantly higher aspect ratio (13.72) compared to Smooth PDMS (1.57) and control surfaces (1.51). 相似文献
60.
Kenneth Micklethwaite Anna Hansen Aaron Foster Elizabeth Snape Vicki Antonenas Mary Sartor Peter Shaw Ken Bradstock David Gottlieb 《Biology of blood and marrow transplantation》2007,13(6):707-714
Cytomegalovirus reactivation and infection post-allogeneic hematopoietic stem cell transplant continue to cause morbidity and mortality. Current pharmacologic therapies are limited by side effects. Adoptive transfer of ex vivo generated cytomegalovirus-specific T cells has the potential to restore immunity, prevent cytomegalovirus, and circumvent the need for pharmacologic therapies. We have generated donor-derived cytomegalovirus-specific cytotoxic T cells using dendritic cells pulsed with the HLA-A2 restricted nonapeptide NLVPMVATV (NLV) derived from the cytomegalovirus-pp65 protein. These cytotoxic T cells have been given prophylactically to 9 recipients aged 4 to 65 years on or after day 28 post-allogeneic hematopoietic stem cell transplant. Only 2 of 9 recipients received T cell depletion in vivo or in vitro. There were no immediate adverse reactions to the infusions. During 97-798 days of follow-up, 2 recipients developed cytomegalovirus reactivation; neither developed cytomegalovirus disease or required pharmacotherapy. Three recipients developed acute graft versus host disease after infusion. Two recipients died, 1 from thrombotic thrombocytopenia purpura secondary to cyclosporine, 1 from complications of graft versus host disease. A transient increase in numbers of cytomegalovirus-specific T cells demonstrated by NLV-tetramer binding was seen in 6 recipients. Prophylactic adoptive transfer of NLV-specific T cells is safe and may be effective in preventing cytomegalovirus reactivation. 相似文献