全文获取类型
收费全文 | 1208篇 |
免费 | 128篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 86篇 |
妇产科学 | 8篇 |
基础医学 | 151篇 |
口腔科学 | 17篇 |
临床医学 | 138篇 |
内科学 | 287篇 |
皮肤病学 | 13篇 |
神经病学 | 66篇 |
特种医学 | 62篇 |
外科学 | 98篇 |
综合类 | 50篇 |
预防医学 | 139篇 |
眼科学 | 10篇 |
药学 | 102篇 |
肿瘤学 | 126篇 |
出版年
2021年 | 17篇 |
2019年 | 15篇 |
2018年 | 19篇 |
2017年 | 16篇 |
2016年 | 17篇 |
2015年 | 16篇 |
2014年 | 28篇 |
2013年 | 34篇 |
2012年 | 40篇 |
2011年 | 46篇 |
2010年 | 31篇 |
2009年 | 41篇 |
2008年 | 47篇 |
2007年 | 57篇 |
2006年 | 30篇 |
2005年 | 38篇 |
2004年 | 40篇 |
2003年 | 35篇 |
2002年 | 41篇 |
2001年 | 36篇 |
2000年 | 25篇 |
1999年 | 30篇 |
1998年 | 30篇 |
1997年 | 26篇 |
1996年 | 26篇 |
1995年 | 22篇 |
1994年 | 34篇 |
1993年 | 18篇 |
1992年 | 34篇 |
1991年 | 29篇 |
1990年 | 28篇 |
1989年 | 27篇 |
1988年 | 40篇 |
1987年 | 20篇 |
1986年 | 34篇 |
1985年 | 25篇 |
1984年 | 22篇 |
1983年 | 15篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 14篇 |
1979年 | 15篇 |
1978年 | 13篇 |
1976年 | 9篇 |
1975年 | 9篇 |
1974年 | 14篇 |
1973年 | 11篇 |
1972年 | 12篇 |
1971年 | 11篇 |
1969年 | 13篇 |
排序方式: 共有1361条查询结果,搜索用时 390 毫秒
41.
42.
The therapeutic and prognostic implications of relapse and clonal evolution of leukaemia are substantially different from those of secondary (induced) malignancy. This report documents the case of a patient who presented with apparent acute non-lymphocytic leukaemia (ANLL) following therapy for acute (T-cell) lymphoblastic leukaemia (ALL) 4 years previously. Morphologically and cytochemically the cells were of myeloid type, but the cell markers showed a T cell lineage. Cytogenetic studies confirmed that this was a relapse of T cell ALL with a phenotypic change, rather than a second malignancy induced by chemotherapy. A 14q deletion present at initial diagnosis recurred at relapse, with the addition of cells with complete deletion of chromosome 14, indicating clonal evolution. 相似文献
43.
Overnutrition induced decrease in insulin action for glucose storage: in vivo and in vitro in man 总被引:8,自引:0,他引:8
The effect of short-term overnutrition on insulin action for glucose disposal was assessed in 15 Southwest American Indians (mean wt = 74 +/- 6 kg). After two weeks of weight maintenance and again after two weeks of 62% greater caloric intake (constant ratio of fat:carbohydrate:protein), insulin action for glucose disposal was measured using the euglycemic clamp technique with plasma insulin concentrations of about 110 and 1800 uU/mL. Simultaneous indirect calorimetry was used to estimate carbohydrate oxidation and storage rates. Following overnutrition, mean weight gain was 3.0 +/- 0.2 kg, P less than 0.01. Overnutrition induced a decrease in glucose storage at the low and high insulin concentrations: 1.2 +/- 0.3 to 0.2 +/- 0.3, P less than 0.01, and 6.4 +/- 0.3 to 4.3 +/- 0.5, mg/kg FFM min, P less than 0.001. Carbohydrate oxidation was significantly increased at both insulin concentrations. The mean total insulin mediated glucose disposal rate decreased from 11.6 +/- 0.5 to 10.3 +/- 0.7, P less than 0.01, at the high insulin concentration. This decrease was due entirely to the reduction in carbohydrate storage and was correlated with increased fasting insulin concentration (r = 0.7, P less than 0.01). Overnutrition also induced a significant decrease in the percent muscle glycogen synthase active measured fasting and at the end of the high-dose insulin infusion. The results indicate that short-term overnutrition results in reduced insulin action for glucose storage and disposal which is correlated with increased fasting insulin concentrations. Reduced glycogen synthase activity may contribute to the effect of overnutrition on in vivo insulin-mediated glucose storage. 相似文献
44.
B L Nyomba B A Swinburn V M Ossowski V L Boyce C Bogardus D M Mott 《The Journal of clinical endocrinology and metabolism》1991,72(6):1212-1219
Insulin receptor tyrosine kinase is an important step in insulin action. We examined the relationship between diet-induced changes in glucose metabolism and changes in skeletal muscle insulin-sensitive tyrosine kinase activity in 12 nondiabetic subjects. Subjects were fed a traditional, high carbohydrate Pima Indian diet and a modern, high fat western diet for 2 weeks in a randomized cross-over design. At the end of each dietary period, glucose tolerance was assessed, insulin sensitivity (SI) was estimated by Bergman's minimal model method, and insulin receptor concentration and tyrosine kinase activity were determined on lectin-purified extracts from quadriceps femoris muscle. Compared to the traditional diet, the modern diet was associated with a deterioration of glucose tolerance and an increase in glucose-induced plasma insulin levels. As expected, SI changes were associated with opposite changes in plasma insulin levels. However, the changes in maximal tyrosine kinase activity were negatively correlated with changes in SI (r = -0.69; P less than 0.01) and positively correlated with changes in plasma glucose (r = 0.70; P less than 0.01) and insulin response to glucose (r = 0.57; P less than 0.025). These results suggest that the site of diet-induced changes in insulin action is beyond the insulin-sensitive tyrosine kinase. The results further suggest that the kinase activity is modulated by prevailing plasma insulin levels. 相似文献
45.
Claudia A. Grillo Gerardo G. Piroli Robert C. Lawrence Shayna A. Wrighten Adrienne J. Green Steven P. Wilson Randall R. Sakai Sandra J. Kelly Marlene A. Wilson David D. Mott Lawrence P. Reagan 《Diabetes》2015,64(11):3927-3936
Insulin receptors (IRs) are expressed in discrete neuronal populations in the central nervous system, including the hippocampus. To elucidate the functional role of hippocampal IRs independent of metabolic function, we generated a model of hippocampal-specific insulin resistance using a lentiviral vector expressing an IR antisense sequence (LV-IRAS). LV-IRAS effectively downregulates IR expression in the rat hippocampus without affecting body weight, adiposity, or peripheral glucose homeostasis. Nevertheless, hippocampal neuroplasticity was impaired in LV-IRAS–treated rats. High-frequency stimulation, which evoked robust long-term potentiation (LTP) in brain slices from LV control rats, failed to evoke LTP in LV-IRAS–treated rats. GluN2B subunit levels, as well as the basal level of phosphorylation of GluA1, were reduced in the hippocampus of LV-IRAS rats. Moreover, these deficits in synaptic transmission were associated with impairments in spatial learning. We suggest that alterations in the expression and phosphorylation of glutamate receptor subunits underlie the alterations in LTP and that these changes are responsible for the impairment in hippocampal-dependent learning. Importantly, these learning deficits are strikingly similar to the impairments in complex task performance observed in patients with diabetes, which strengthens the hypothesis that hippocampal insulin resistance is a key mediator of cognitive deficits independent of glycemic control. 相似文献
46.
Lineage-restricted regulation of the murine SCL/TAL-1 promoter 总被引:10,自引:2,他引:10
Bockamp EO; McLaughlin F; Murrell AM; Gottgens B; Robb L; Begley CG; Green AR 《Blood》1995,86(4):1502-1514
47.
Dinesh R Singh Geoiphy G Pulickal Zhiwen J Lo Wilfred CG Peh 《Singapore medical journal》2015,56(9):523-527
A 28-year-old Chinese man presented with acute bleeding per rectum. Computed tomography showed a posterior outpouching arising from the distal ileum. The outpouching had hyperaemic walls, but no active contrast extravasation was detected. Technetium-99m pertechnetate scintigraphy showed focal areas of abnormal uptake in the right side of the pelvis, superior and posterior to the urinary bladder. These areas of uptake appeared simultaneously with the gastric uptake and demonstrated gradual increase in intensity on subsequent images. The diagnosis of Meckel’s diverticulum was confirmed on surgery and the lesion was resected. The clinical and imaging features of Meckel’s diverticulum are discussed. 相似文献
48.
Busch MP; Laycock M; Kleinman SH; Wages JW Jr; Calabro M; Kaplan JE; Khabbaz RF; Hollingsworth CG 《Blood》1994,83(4):1143-1148
Blood donations in the United States have been screened for antibody to human T-lymphotropic virus type I (HTLV-I) by HTLV-I enzyme immunoassay (EIA) since November 1988. Specimens repeatedly found to be reactive by EIA undergo confirmation by supplementary serologic tests. We assessed the accuracy of blood center testing of 994 HTLV-I EIA repeat-reactive specimens in five US blood centers between November 1988 and December 1991. Of 410 confirmed HTLV-I/II donations, 407 (99.3%) were infected with HTLV-I/II, as determined by polymerase chain reaction (PCR) (403 cases) and by repeat serologic testing (4 cases). The three false- positive results occurred in the first year of testing. Of 425 HTLV- indeterminate specimens, 6 (1.4%) were found to be infected by PCR (5 with HTLV-II and 1 with HTLV-I). None of 159 confirmatory test-negative donations was PCR positive. Of HTLV-I/II-seropositive specimens, 80.2% to 95.4% could be typed as HTLV-I or HTLV-II by type-specific serologic assays. These results support recommendations that HTLV-I/II- seropositive donors should be advised that they are infected with HTLV- I, HTLV-II, or HTLV-I/II (depending on results of type-specific assays). HTLV-indeterminate donors should be advised that their results only rarely indicate HTLV infection. HTLV confirmatory test-negative donors should be reassured that they are not infected with HTLV-I or HTLV-II. 相似文献
49.
Brittany R. Alperin Katherine K. Mott Dorene M. Rentz Phillip J. Holcomb Kirk R. Daffner 《Psychophysiology》2014,51(7):620-633
An age‐related “anterior shift” in the distribution of the P3b is often reported. Temporospatial principal component analysis (PCA) was used to investigate the basis of this observation. ERPs were measured in young and old adults during a visual oddball task. PCA revealed two spatially distinct factors in both age groups, identified as the posterior P3b and anterior P3a. Young subjects generated a smaller P3a than P3b, while old subjects generated a P3a that did not differ in amplitude from their P3b. Rather than having a more anteriorly distributed P3b, old subjects produced a large, temporally overlapping P3a. The pattern of the age‐related “anterior shift” in the P3 was similar for target and standard stimuli. The increase in the P3a in elderly adults may not represent a failure to habituate the novelty response, but may reflect greater reliance on executive control operations (P3a) to carry out the categorization/updating process (P3b). 相似文献
50.
Laurentiu Zolotusca Pernille Jorgensen Odette Popovici Adriana Pistol Florin Popovici Marc‐Alain Widdowson Viorel Alexandrescu Alina Ivanciuc Po‐Yung Cheng Diane Gross Caroline S. Brown Joshua A. Mott 《Influenza and other respiratory viruses》2014,8(1):8-12