全文获取类型
收费全文 | 3936篇 |
免费 | 227篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 31篇 |
儿科学 | 213篇 |
妇产科学 | 57篇 |
基础医学 | 378篇 |
口腔科学 | 68篇 |
临床医学 | 332篇 |
内科学 | 967篇 |
皮肤病学 | 29篇 |
神经病学 | 273篇 |
特种医学 | 550篇 |
外国民族医学 | 6篇 |
外科学 | 442篇 |
综合类 | 38篇 |
一般理论 | 1篇 |
预防医学 | 117篇 |
眼科学 | 50篇 |
药学 | 337篇 |
中国医学 | 3篇 |
肿瘤学 | 298篇 |
出版年
2022年 | 21篇 |
2021年 | 46篇 |
2020年 | 34篇 |
2019年 | 30篇 |
2018年 | 48篇 |
2017年 | 32篇 |
2016年 | 42篇 |
2015年 | 63篇 |
2014年 | 71篇 |
2013年 | 131篇 |
2012年 | 103篇 |
2011年 | 108篇 |
2010年 | 129篇 |
2009年 | 120篇 |
2008年 | 115篇 |
2007年 | 116篇 |
2006年 | 139篇 |
2005年 | 139篇 |
2004年 | 137篇 |
2003年 | 107篇 |
2002年 | 105篇 |
2001年 | 109篇 |
2000年 | 111篇 |
1999年 | 123篇 |
1998年 | 166篇 |
1997年 | 150篇 |
1996年 | 161篇 |
1995年 | 127篇 |
1994年 | 99篇 |
1993年 | 102篇 |
1992年 | 77篇 |
1991年 | 70篇 |
1990年 | 62篇 |
1989年 | 117篇 |
1988年 | 81篇 |
1987年 | 105篇 |
1986年 | 79篇 |
1985年 | 88篇 |
1984年 | 66篇 |
1983年 | 54篇 |
1982年 | 49篇 |
1981年 | 34篇 |
1980年 | 56篇 |
1979年 | 38篇 |
1978年 | 34篇 |
1977年 | 23篇 |
1976年 | 29篇 |
1975年 | 34篇 |
1973年 | 14篇 |
1968年 | 13篇 |
排序方式: 共有4190条查询结果,搜索用时 15 毫秒
991.
Value of beta 2-microglobulin level and plasma cell labeling indices as prognostic factors in patients with newly diagnosed myeloma 总被引:4,自引:3,他引:4
Beta 2-microglobulin (beta 2M) has been proposed as a prognostic factor in multiple myeloma (MM), but beta 2M levels are reported to correlate with other prognostic indicators such as stage and creatinine level. This study addressed the independent prognostic values of these and other variables, including plasma cell labeling indices (LI), in patients with newly diagnosed MM. beta 2M levels were measured with an enzyme-linked immunosorbent assay. LI were determined with a [3H]thymidine autoradiography method. By multivariate analysis and Kaplan-Meier survival analysis, the uncorrected beta 2M level remained the most significant prognostic factor after adjustment for age. Stage and creatinine level were closely related to beta 2M level and were no longer predictive of outcome after adjustment for age and beta 2M. Plasma cell LI varied independently of beta 2M level and remained predictive. A subset of patients with plasma-blastic myeloma had poor survival since beta 2M level and plasma cell LI were high. By using beta 2M level and LI, three risk groups were defined: low (beta 2M less than 4 micrograms/mL and LI less than 0.4%, median survival 48 months); intermediate (beta 2M less than 4 micrograms/mL and LI greater than or equal to 0.4%, median survival 29 months); and high (beta 2M greater than or equal to 4 micrograms/mL, median survival 12 months). Such grouping may better identify MM patients who might benefit from new treatment regimens. 相似文献
992.
Monoclonal antibodies to human protein S have been prepared using established hybridoma technology. One antibody was isolated that binds protein S only when Ca2+ is present; others bind antigen equally well in the presence or absence of EDTA. Other antibodies display a diminished affinity for protein S in the presence of EDTA. Purified immunoglobulins from cell lines displaying Ca2+ dependence were immobilized and used to purify protein S from fractions obtained by barium precipitation of citrated plasma, ammonium sulfate fractionation, and chromatography on diethylaminoethanol (DEAE)- Sephadex and dextran sulfate agarose. Essentially homogeneous protein S was isolated from the barium-citrate-adsorbed, 35% ammonium-sulfate- soluble proteins using a totally Ca2+-dependent antibody and EDTA elution. Protein S and several substances of higher mol wt were bound directly from plasma by a partially Ca2+-dependent antibody and were eluted partially with EDTA and NaCl and finally with NaSCN. The largest and most abundant of the high mol wt materials is likely protein S- complement C4b-binding protein complex. The immunoaffinity-isolated protein S was found to be indistinguishable from conventionally isolated protein S in terms of activity, sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) mobility, and by high- performance liquid chromatography (HPLC). These studies establish reagents that can probe the structure of protein S and isolate protein S in its free and complexed forms. 相似文献
993.
Increased soluble interleukin-1 type II receptor concentrations in postoperative patients and in patients with sepsis syndrome 总被引:7,自引:0,他引:7
Pruitt JH; Welborn MB; Edwards PD; Harward TR; Seeger JW; Martin TD; Smith C; Kenney JA; Wesdorp RI; Meijer S; Cuesta MA; Abouhanze A; Copeland EM rd; Giri J; Sims JE; Moldawer LL; Oldenburg HS 《Blood》1996,87(8):3282-3288
Plasma interleukin-1 (IL-1) activity is modulated in part through the simultaneous appearance of several inhibitors of IL-1 action, including interleukin-1 receptor antagonist (IL-1ra) and the soluble IL-1 type II receptor (IL-1RII). However, little is known concerning the plasma appearance of these inhibitors in patients following operative trauma or those with sepsis syndrome. In the present report, plasma IL-1beta, IL-1ra, and soluble IL-1RI and IL-1RII concentrations were evaluated in 118 patients with sepsis syndrome or after elective operative trauma. Plasma concentrations of IL-1ra increased significantly following elective operative repair of thoraco-abdominal and abdominal aortic aneurysms, and after bowel resection for inflammatory bowel disease, but did not increase after laparoscopic cholecystectomy. Plasma IL-1ra levels were also elevated in patients with sepsis syndrome. In contrast, soluble IL-1RII levels were only increased in patients after operative repair of thoraco-abdominal aortic aneurysms and in sepsis syndrome, whereas concentrations were unaffected by the other more modest surgical procedures. Plasma IL-1RI concentrations decreased in all postoperative patients in the first 24 hours after surgery. We conclude that both plasma IL-1ra and soluble IL-1RII concentrations often increase in sepsis and following some operative trauma. Less severe operative trauma increases the plasma concentration of only IL- 1ra, whereas both IL-1ra and soluble IL-1RII are increased in patients with sepsis syndrome or following thoraco-abdominal aneurysm repair. 相似文献
994.
Human herpesvirus 6: infection and disease following autologous and allogeneic bone marrow transplantation 总被引:3,自引:0,他引:3
Kadakia MP; Rybka WB; Stewart JA; Patton JL; Stamey FR; Elsawy M; Pellett PE; Armstrong JA 《Blood》1996,87(12):5341-5354
Human herpesvirus 6 activity (HHV-6) was studied in 15 allogeneic and 11 autologous marrow transplantation patients. After transplantation, HHV-6 was isolated from the peripheral blood mononuclear cells of 12 of 26 patients (6 allogeneic and 6 autologous). All isolates were variant B. Eleven of 26 and 12 of 19 patients showed salivary shedding of HHV-6 DNA before and after transplantation, respectively. The antibody titer increased in 7 of 26 patients. Thus, 23 of 26 patients showed evidence of active HHV-6 infection either by virus isolation, salivary shedding, or increases in antibody titers. The fraction of saliva specimens positive in 19 patients was negatively associated with their antibody titers (P= .005). The proportion of cultures positive increased after transplantation (P = .007). Sinusitis was associated with HHV-6 isolation in autologous recipients (P= .002). In allogeneic patients, active human cytomegalovirus infection was associated with HHV-6 isolation (P = .04). No association was observed between HHV-6 infection and GVHD, pneumonia, delay in engraftment, or marrow suppression. Of the 120 clinical events analyzed in 26 patients, HHV-6 was defined as a probable cause of 16 events in 9 patients based on the propinquity of HHV-6 activity and the clinical event plus the absence of other identified causes of the event. 相似文献
995.
Protective effect of prophylactic penicillin on splenectomized mice exposed to an aerosolized suspension of type III Streptococcus pneumoniae 总被引:1,自引:0,他引:1
Prophylactic penicillin has been recommended for use in asplenic patients and postsplenectomy patients. A laboratory model using aerosolized pneumococci has been devised to test the effectiveness of prophylactic penicillin in a manner analogous to human experience. There is increased mortality, over time, in asplenic mice exposed to aerosolized type III Streptococcus pneumoniae. One hundred twenty-one male Swiss mice (mean weight 26 g) were divided into four groups: splenectomized, sham-operated, splenectomized + penicillin, and sham- operated + penicillin. After 2 wk the four groups were exposed for 30 min to an aerosolized atmosphere of 2.4 x 10(9) colony-forming units of type III S. pneumoniae using a Tri-R model A-42 airborne infection apparatus. Penicillin was given at a daily intramuscular dosage of 40,000 units procaine penicillin G beginning 2 days prior to exposure and continuing through the third day after exposure. The splenectomized and sham-operated mice given penicillin showed significantly lower mortality (p less than 0.001) than mice not given penicillin. 相似文献
996.
Ruiz-Arguelles GJ; Katzmann JA; Greipp PR; Gonchoroff NJ; Garton JP; Kyle RA 《Blood》1984,64(2):352-356
The bone marrow and peripheral blood of 14 patients with multiple myeloma were studied with murine monoclonal antibodies that identify antigens on plasma cells (R1-3 and OKT10). Peripheral blood lymphocytes expressing plasma cell antigens were found in six cases. Five of these cases expressed the same antigens that were present on the plasma cells in the bone marrow. Patients that showed such peripheral blood involvement were found to have a larger tumor burden and higher bone marrow plasma cell proliferative activity. In some patients, antigens normally found at earlier stages of B cell differentiation (B1, B2, and J5) were expressed by peripheral blood lymphocytes and/or bone marrow plasma cells. 相似文献
997.
Characteristics of bone marrow fibroblast colony-forming cells (CFU-F) and their progeny in patients with myeloproliferative disorders 总被引:4,自引:1,他引:4
Castro-Malaspina H; Gay RE; Jhanwar SC; Hamilton JA; Chiarieri DR; Meyers PA; Gay S; Moore MA 《Blood》1982,59(5):1046-1054
Chronic myeloproliferative disorders (MPD) are clonal diseases of the pluripotent hematopoietic stem cell frequently associated with myelofibrosis (MF). There is only indirect evidence indicating that the increased deposition of collagen in bone marrow matrix is a secondary phenomenon. A liquid culture system for cloning and growing bone marrow fibroblasts has permitted us to approach more directly the understanding of the pathogenesis of myelofibrosis by comparing the biophysical, growth, and functional characteristics of fibroblasts from normals, MPD patients without MF, and those with MF. In patients with MF, marrow fibroblast colony (CFU-F) formation could not be studied; fibroblasts were grown from marrow explants. CFU-E from normals and MPD patients exhibited similar cell density distribution and similar cell sedimentation rates. These similarities contrasted sharply with the differences seen when the erythroid and granulocyte-macrophage progenitors were studied by the same methods. There was a marked light density shift and a rapidly sedimenting shift of MPD hematopoietic colony-forming cells. Marrow fibroblasts from MPD patients with and without MF displayed the same in vitro growth characteristics as fibroblasts from normals. Both types of fibroblasts exhibited anchorage and serum dependence, and contact inhibition of growth. Marrow fibroblasts were also characterized for the presence and distribution of fibronectin and collagen types by immunofluorescent staining using monospecific antibodies. Extracellular matrix, membrane-, and cytoplasm- associated fibronectin, type I, type III, and type V collagen showed a similar staining pattern in both normal and myelofibrotic marrow fibroblasts. Plasminogen-dependent fibrinolytic activity elicited from normal and myelofibrotic marrow fibroblasts were equivalent. Chromosomal analysis of hematopoietic cells and marrow fibroblasts from Philadelphia chromosome positive chronic myelocytic leukemia patients with and without MF showed that the Philadelphia chromosome was present only in hematopoietic cells. The results of these studies taken together demonstrate that bone marrow collagen-producing cells from MPD patients with and without MF behave in vitro as do those from normals. These findings support the hypothesis that that the marrow fibrosis observed in patients with MPD results from a reactive process rather than from a primary disorder affecting the marrow collagen-producing cells. 相似文献
998.
The purpose of this study was to quantitate the number and labeling index of monoclonal plasma cells in the blood of patients with newly diagnosed multiple myeloma (MM) to learn if these values were independent prognostic factors for survival. Patients were candidates for this study if they had untreated myeloma requiring therapy, were evaluated at our institution between 1984 and 1993, and had a sample of blood analyzed with a sensitive immunofluorescence technique for monoclonal plasma cells and the blood B-cell labelling index (BLI). The % blood monoclonal plasma cells (%BPC) and the BLI were analyzed along with stage, marrow plasma cell LI, % marrow plasma cells, calcium, creatinine, albumin, beta-2-microglobulin, and C-reactive protein as univariate and multivariate factors for survival. Eighty percent of the 254 patients accrued to this study had monoclonal BPC detected. The median % BPC was 6% and 57% (144 of 254) of patients had a high number (> or = 4%). Patients with > or = 4% BPC had a median survival of 2.4 years vs 4.4 years for those with < 4% BPC (P < .001). The BLI was also prognostic (P = .008). In a multivariate analysis, the % BPC, age, albumin, stage, marrow plasma cell LI, and the BLI were independent factors for survival. The %BPC and the marrow plasma cell LI best separated the group into low, intermediate, and high risk myeloma with median survivals of 52, 35, and 26 months, respectively. Patients with high %BPC were less likely to have lytic bone disease from their MM (P = .002). The %BPC and the BLI are independent prognostic factors for survival and are useful in identifying patients as low, intermediate, and high risk. Clonal cells in the blood should be quantified in future clinical trials for myeloma. 相似文献
999.
- Ventricular pacing is mandatory in many structural interventions, with associated risks like tamponade and capture loss.
- The Tempo pacing wire was designed to deal with these issues incorporating an elastomeric balloon on the tip and an active fixation system.
- In this initial multicenter experience, Tempo pacing wire demonstrated an outstanding performance in both safety and efficacy aspects of ventricular pacing during and after structural interventions.
1000.
The kinetics of iron uptake by isolated intestinal cells from normal mice and mice with sex-linked anemia 总被引:2,自引:1,他引:2
No significant differences of Km or Vmax could be demonstrated for the initial rate (0-3 min) of iron uptake by preparations of isolated duodenal mucosal epithelial cells from normal or sex-linked anemic (sla) mice. Isolated cells from sla mice do, however, take up significantly more iron than normal cells after 20-min incubation. Upon reincubation with various types of mobilizing agents, the amount of iron released from, and the amount of iron remaining in, cells from sla mice was significantly elevated compared to control values. The percentage of iron released was the same for both types of cells, for all mobilization media employed. The current data, in conjunction with previous studies that showed deficient mucosal to serosal transport of iron in everted duodenal sacs from sla mice, suggest that the lesion in these mice may be located between the mucosal cell and the vascular compartment rather than in the mucosal cell. 相似文献