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排序方式: 共有2043条查询结果,搜索用时 10 毫秒
991.
D T Dudley L Pang S J Decker A J Bridges A R Saltiel 《Proceedings of the National Academy of Sciences of the United States of America》1995,92(17):7686-7689
Treatment of cells with a variety of growth factors triggers a phosphorylation cascade that leads to activation of mitogen-activated protein kinases (MAPKs, also called extracellular signal-regulated kinases, or ERKs). We have identified a synthetic inhibitor of the MAPK pathway. PD 098059 [2-(2'-amino-3'-methoxyphenyl)-oxanaphthalen-4-one] selectively inhibited the MAPK-activating enzyme, MAPK/ERK kinase (MEK), without significant inhibitory activity of MAPK itself. Inhibition of MEK by PD 098059 prevented activation of MAPK and subsequent phosphorylation of MAPK substrates both in vitro and in intact cells. Moreover, PD 098059 inhibited stimulation of cell growth and reversed the phenotype of ras-transformed BALB 3T3 mouse fibroblasts and rat kidney cells. These results indicate that the MAPK pathway is essential for growth and maintenance of the ras-transformed phenotype. Further, PD 098059 is an invaluable tool that will help elucidate the role of the MAPK cascade in a variety of biological settings. 相似文献
992.
N D Bridges J E Mayer J E Lock R A Jonas F L Hanley J F Keane S B Perry A R Castaneda 《Circulation》1992,86(6):1762-1769
BACKGROUND. The "fenestrated Fontan" (surgical baffle fenestration followed by transcatheter test occlusion and permanent closure after postoperative recovery) was adopted in an effort to reduce perioperative mortality and morbidity. This study assesses the effect of baffle fenestration on outcome. METHODS AND RESULTS. Patients having a modified Fontan operation with a cavocaval baffle and cavopulmonary anastomosis were retrospectively selected for study. Those with baffle fenestration (n = 91) were compared with those without baffle fenestration (n = 56) with respect to preoperative risk factors, age, anatomy, surgical date, and presence or absence of a previous bidirectional cavopulmonary anastomosis. Outcome variables were failure (death or take-down) and duration of postoperative pleural effusions and hospitalization. Survival and clinical status after hospital discharge were ascertained. The two groups did not appear to differ with respect to age or anatomic diagnosis. Patients having baffle fenestration were at significantly greater preoperative risk by univariate and multivariate analysis (p < 0.01). Operative failure was low in both groups (11% without and 7% with baffle fenestration, p = NS). Durations of pleural effusions and hospitalization were significantly shorter with baffle fenestration (p < 0.01). Neither date of surgery nor a previous bidirectional cavopulmonary anastomosis appeared to contribute to improved outcome. Patients with baffle fenestration had lower postoperative systemic venous pressure (p < 0.01). There were no late deaths. Functional status in both groups is good (82% in New York Heart Association class I). CONCLUSIONS. Baffle fenestration is associated with low mortality, significantly less pleural effusion, and significantly shorter hospitalization among high-risk patients having a modified Fontan operation. 相似文献
993.
Murphy WJ; Funakoshi S; Beckwith M; Rushing SE; Conley DK; Armitage RJ; Fanslow WC; Rager HC; Taub DD; Ruscetti FW 《Blood》1995,86(5):1946-1953
CD40 is expressed on both normal and neoplastic B lymphocytes. Signal transduction through CD40 in vitro has been shown to exert stimulatory effects on normal B cells and inhibitory effects on Epstein-Barr virus (EBV)-induced B-cell lymphoma lines and some other cell lines derived from patients with aggressive histology lymphoma. The transfer of normal human peripheral blood lymphocytes (huPBL) from EBV-seropositive donors into severe combined immune deficient (SCID) mice has been previously shown to result in the generation of human B-cell lymphomas. These tumors are similar to the highly aggressive EBV-induced lymphomas that can arise clinically after transplantation or in the setting of immunodeficiency. Treatment of huPBL-SCID chimeric mice with anti-CD40 or anti-CD20 monoclonal antibodies (MoAb) significantly delayed the development of EBV-induced B-cell lymphoma. However, the effects of the two MoAb were mechanistically distinct. Anti-CD40 treatment prevented lymphoma generation, while still allowing for functional human B-cell engraftment in the huPBL-SCID mice compared with mice receiving no treatment, all of which succumbed to lymphoma. By contrast, treatment with anti-CD20 significantly inhibited total human B-cell engraftment in the SCID recipients, which accounted for the absence of lymphomas. In vitro assays examining the transformation of human B cells by EBV also indicated that anti-CD40 could directly inhibit EBV- transformation, whereas anti-CD20 antibodies had no effect. Thus, anti- CD40 exerts selective effects to allow for the engraftment of normal human B cells and prevent the emergence of EBV lymphomas. Stimulation of CD40 by antibodies or its physiologic ligand may, therefore, be of significant clinical use in the prevention of EBV-induced B lymphomas that may arise when EBV-seropositive individuals receive immunosuppressive regimens after transplantation or in immune deficiency states, such as acquired immune deficiency syndrome. 相似文献
994.
995.
Should methotrexate be discontinued before elective orthopedic surgery in patients with rheumatoid arthritis? 总被引:1,自引:0,他引:1
S L Bridges A López-Méndez K H Han I C Tracy G S Alarcón 《The Journal of rheumatology》1991,18(7):984-988
To determine if methotrexate (MTX) contributes to early postoperative complications, we studied 38 patients with rheumatoid arthritis (RA) who underwent elective orthopedic surgery. There were 4 complications of prosthetic joint infection or wound dehiscence or infection among 19 procedures performed on patients who continued MTX until less than 4 weeks before surgery, compared to no complications among 34 procedures performed on patients who discontinued MTX 4 weeks before surgery or who were taking no remittive agent for 3 months before surgery (p less than 0.03, Fisher's exact, 2-tailed). No demographic, clinical, laboratory, nutritional, or intraoperative differences between the 2 groups were apparent, suggesting that MTX may play a role in early postoperative complications in patients with RA. A larger, prospective trial to study this issue is warranted. 相似文献
996.
Antibody response in individuals infected with avian influenza A (H5N1) viruses and detection of anti-H5 antibody among household and social contacts 总被引:21,自引:0,他引:21
Katz JM Lim W Bridges CB Rowe T Hu-Primmer J Lu X Abernathy RA Clarke M Conn L Kwong H Lee M Au G Ho YY Mak KH Cox NJ Fukuda K 《The Journal of infectious diseases》1999,180(6):1763-1770
The first documented outbreak of human respiratory disease caused by avian influenza A (H5N1) viruses occurred in Hong Kong in 1997. The kinetics of the antibody response to the avian virus in H5N1-infected persons was similar to that of a primary response to human influenza A viruses; serum neutralizing antibody was detected, in general, >/=14 days after symptom onset. Cohort studies were conducted to assess the risk of human-to-human transmission of the virus. By use of a combination of serologic assays, 6 of 51 household contacts, 1 of 26 tour group members, and none of 47 coworkers exposed to H5N1-infected persons were positive for H5 antibody. One H5 antibody-positive household contact, with no history of poultry exposure, provided evidence that human-to-human transmission of the avian virus may have occurred through close physical contact with H5N1-infected patients. In contrast, social exposure to case patients was not associated with H5N1 infection. 相似文献
997.
Inhibition of human B-cell lymphoma growth by CD40 stimulation 总被引:15,自引:4,他引:15
Funakoshi S; Longo DL; Beckwith M; Conley DK; Tsarfaty G; Tsarfaty I; Armitage RJ; Fanslow WC; Spriggs MK; Murphy WJ 《Blood》1994,83(10):2787-2794
CD40 is a molecule present on B lymphocyte lineage cells that is important in B-cell differentiation and activation. Signaling through CD40 has been shown to exert costimulatory signals on normal B cells resulting in proliferative and differentiation responses. Examination of several B-cell lymphomas showed cell-surface expression of the CD40 molecule. Incubation of these lymphomas with anti-CD40 antibodies resulted in significant growth inhibition in vitro. Cross-linking of the CD40 antibodies resulted in even greater inhibition of proliferation. A recombinant soluble human CD40 ligand was also shown to inhibit lymphoma proliferation. When various human B-cell lymphomas were transferred into mice with severe combined immune deficiency, the treatment of the mice with anti-CD40 antibodies resulted in significant increases in survival showing that anti-CD40 is efficacious after in vivo administration. Thus, CD40 stimulation by either the antibody or soluble ligand directly inhibits human B-cell lymphoma growth and therefore, may be of significant clinical use in their treatment. 相似文献
998.
Mutagenic repair in Escherichia coli: products of the recA gene and of the umuD and umuC genes act at different steps in UV-induced mutagenesis. 总被引:22,自引:13,他引:22 下载免费PDF全文
B A Bridges R Woodgate 《Proceedings of the National Academy of Sciences of the United States of America》1985,82(12):4193-4197
When excision-deficient Escherichia coli carrying umuC or umuD alleles were exposed to visible light several hours after ultraviolet irradiation, base-pair-substitution mutations were induced in these normally non-UV-mutable bacteria. It is argued that delayed photoreversal of pyrimidine dimers removes blocks to DNA replication and allows the "survival" and expression of misincorporated bases. A model for UV mutagenesis is proposed with two steps: (i) misincorporation opposite a photoproduct, which can be mediated directly by RecA protein, and (ii) bypass, only the latter process requiring umuD+ and umuC+ alleles. Basal levels of gene products are sufficient for at least some misincorporation events, although induced levels of umuD and umuC gene products are necessary for the bypass step. umuC bacteria containing the recA441 allele showed a greater yield of mutants, and those containing recA430 a reduced yield, following delayed photoreversal. The lexA51 allele (which results in constitutive derepression of RecA protein production) did not significantly alter the yield of mutants but caused them to appear marginally sooner in a recA441 umuC strain. These results emphasize that the nature of the RecA protein and not its concentration is paramount in determining the level of misincorporation. Experiments with recA441 umuC bacteria at 43 degrees C and 30 degrees C suggest that the misincorporation effect is unlikely to be attributable to cleavage of a DNA binding protein such as a repressor or a component of the polymerase complex. Moreover, misincorporation seems to occur without the need for induced synthesis of any other protein under recA control. 相似文献
999.
Pulmonary arteriovenous malformations (PAVM) are a rare cause of cyanosis in neonates. A large PAVM in a neonate was successfully occluded by transcatheter embolisation. At six months follow up the PAVM was undetectable and no new lesions were found. Transcatheter embolisation should be considered as the primary treatment for a PAVM in a child of any age. 相似文献
1000.
Immunosuppressive therapy of Factor VIII inhibitors 总被引:1,自引:0,他引:1
Hultin MB; Shapiro SS; Bowman HS; Gill FM; Andrews AT; Martinez J; Eyster EM; Sherwood WC 《Blood》1976,48(1):95-108
Immunosuppressive therapy was used in seven hemophiliac and three nonhemophiliac patients with factor VIII inhibiors. Permanent disappearance of the inhibitor occurred in three hemophiliac and two nonhemophiliac patients following treatment with cyclophosphamide and factor VIII. Critical factors influencing the response to therapy may include both the titer and duration of the inhibitor and the degree of intervening factor VIII exposure prior to immunosuppressive therapy. Two severe hemophiliacs with low titer inhibitors that disappeared without specific therapy are also reported. 相似文献