全文获取类型
收费全文 | 1057篇 |
免费 | 46篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 68篇 |
妇产科学 | 30篇 |
基础医学 | 196篇 |
口腔科学 | 42篇 |
临床医学 | 117篇 |
内科学 | 216篇 |
皮肤病学 | 15篇 |
神经病学 | 140篇 |
特种医学 | 131篇 |
外科学 | 39篇 |
综合类 | 13篇 |
预防医学 | 26篇 |
眼科学 | 4篇 |
药学 | 64篇 |
1篇 | |
肿瘤学 | 32篇 |
出版年
2024年 | 5篇 |
2023年 | 7篇 |
2022年 | 10篇 |
2021年 | 10篇 |
2020年 | 8篇 |
2019年 | 9篇 |
2018年 | 14篇 |
2017年 | 16篇 |
2016年 | 26篇 |
2015年 | 31篇 |
2014年 | 36篇 |
2013年 | 47篇 |
2012年 | 26篇 |
2011年 | 37篇 |
2010年 | 29篇 |
2009年 | 32篇 |
2008年 | 34篇 |
2007年 | 63篇 |
2006年 | 34篇 |
2005年 | 21篇 |
2004年 | 15篇 |
2003年 | 14篇 |
2002年 | 17篇 |
2001年 | 16篇 |
2000年 | 14篇 |
1999年 | 22篇 |
1998年 | 46篇 |
1997年 | 54篇 |
1996年 | 61篇 |
1995年 | 47篇 |
1994年 | 32篇 |
1993年 | 31篇 |
1992年 | 15篇 |
1991年 | 18篇 |
1990年 | 13篇 |
1989年 | 21篇 |
1988年 | 34篇 |
1987年 | 27篇 |
1986年 | 23篇 |
1985年 | 17篇 |
1984年 | 13篇 |
1983年 | 13篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1980年 | 11篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1975年 | 9篇 |
1970年 | 8篇 |
1969年 | 4篇 |
排序方式: 共有1149条查询结果,搜索用时 78 毫秒
21.
Immunologic heterogeneity of diffuse large cell lymphoma 总被引:2,自引:0,他引:2
Freedman AS; Boyd AW; Anderson KC; Fisher DC; Pinkus GS; Schlossman SF; Nadler LM 《Blood》1985,65(3):630-637
The cellular lineage of 57 diffuse large-cell lymphomas (DLCLs) was determined using a panel of monoclonal antibodies directed against lineage-restricted and -associated T, B, and monocyte antigens. The majority (82%) were of B cell lineage as determined by the expression of sig and/or B1, with the remaining 16% being of T cell lineage and 2%, of monocyte-myeloid lineage. By the expression of other B cell- restricted and -associated antigens, two major and two minor subgroups could be identified. These subgroups expressed the following phenotypes: (1) B1+B4+sIG+B2- (51%); (2) B1+B4+sIg+B2+ (29%); (3) B1+B4+sIg-B2+ (10%); and (4) B1+B4-sIg+B2- (10)%. The morphology of transformed lymphocytes, the weak to absent expression of the early B cell antigens B2 and sIgD, and the absence of the late B cell differentiation antigens PCA-1 and PC-1 suggested that these tumors were the neoplastic counterparts of normal B cells at the mid-stages of differentiation. Further support for the notion that B-DLCLs correspond to transformed B lymphocytes was concluded from the observation that B cells could be identified in normal spleen that expressed the cell surface phenotype and morphological appearance of the majority of B- DLCLs. 相似文献
22.
Peripheral blood lymphocytes (PBLs) from multiple myeloma patients are defective in both proportion and absolute numbers of OKT4+ cells and have a normal proportion but reduced absolute number of OKT8+ cells. To assess the functional capabilities of the T cells in myeloma patients, we cloned the T cells in PBLs using limiting dilution conditions in which 100% of OKT4+ and OKT8+ T cells in normal PBLs are able to form a clone. In contrast, the OKT8+ cells from PBLs of five of seven multiple myeloma patients were severely compromised in their clonogenic potential; only 7% to 25% of OKT8+ T cells appeared to give rise to a clone. Clonogenic potential of the OKT4+ cells in patients was more nearly normal. Analysis of two multiple myeloma patients with abnormally low numbers of T cells in PBLs revealed the existence of abnormalities in the progenitors of T cell clones. In both patients, two to three times as many T cell clones were observed as would have been expected based on the number of PBLs cultured at limiting dilution, indicating that OKT4-8- cells in PBLs are capable of giving rise to OKT4+ and, at lower frequency, to OKT8+ clonal progeny in vitro. We conclude that purely quantitative assessment of T cell subsets should be interpreted with caution, since proportionately normal numbers of OKT8+ cells in patient PBLs are seriously compromised in their ability to give rise to clonal progeny in vitro, and since there appears to be a OKT4-8- population of T cells in PBLs that are committed to become OKT4+ or OKT8+ T cells, but are unable to do so in vivo. 相似文献
23.
Objective To detect new mutations among 29 glucose-6-phosphate dehydrogenase (G6PD) deficient individuals from Yunnan province. Methods The nitroblue tetrazolium (NBT) method was used to screen G6PD deficient individuals. Mutation was identified by single strand conformation polymorphism (SSCP), amplification created restriction site (ACRS), amplification refractory mutation system (ARMS) and DNA sequencing. Results Among 29 cases, 18 cases of G1388A, 1 case of C1004A, and 1 case of G1381A were identified. Nine cases remained to be defined. The G1381A mutation is a novel mis-sense mutation, with a substitution of threonine for alanine (A461T). The resultant G6PD had reduced enzymatic activity. In addition, G1381A caused a restriction site of Stu I to disappear, providing a rapid method for the detection of this mutation. Conclusion A novel mis-sense mutation G1381A was found. This mutation results in a substitution of threonine for alanine, producing enzyme with reduced activity. The loss of the Stu I restriction site offers a rapid method for the detection of this mutation. 相似文献
24.
Jacek Nowak Marco Ylan Inger Hagerman Olof Nyquist Christer Sylven 《Clinical cardiology》1993,16(9):671-682
Variance electrocardiography (variance ECG) is a new resting procedure for detection of coronary artery disease (CAD). The method measures variability in the electrical expression of the depolarization phase induced by this disease. The time-domain analysis is performed on 220 cardiac cycles using high-fidelity ECG signals from 24 leads, and the phase-locked temporal electrical heterogeneity is expressed as a nondimensional CAD index (CAD-I) with the values of 0–150. This study compares the diagnostic efficiency of variance ECG and exercise stress test in a high prevalence population. A total of 199 symptomatic patients evaluated with coronary angiography was subjected to variance ECG and exercise test on a bicycle ergometer as a continuous ramp. The discriminant accuracy of the two methods was assessed employing the receiver operating characteristic curves constructed by successive consideration of several CAD-I cutpoint values and various threshold criteria based on ST-segment depression exclusively or in combination with exertional chest pain. Of these patients, 175 with CAD (≥ 50% luminal stenosis in 1 + major epicardial arteries) presented a mean CAD-I of 88 ± 22, compared with 70 ± 21 in 24 nonaffected patients (p < 0.01). Variance ECG provided a stochastically significant discrimination (p < 0.01) which was matched by exercise test only when chest pain variable was added to ST-segment depression as a discriminating criterion. Even then, the exercise test diagnosed single-vessel disease with a significantly lower sensitivity. At a cutpoint of CAD-I ≥ 70, compared with ST-segment depression ≥ 1 mm combined with exertional chest pain, the overall sensitivity of variance ECG was significantly higher (p < 0.01) than that of exercise test (79 vs. 48 %). When combined, the two methods identified 93% of coronary angiography positive cases. Variance ECG is an efficient diagnostic method which compares favorably with exercise test for detection of CAD in high prevalence population. 相似文献
25.
Fucoidin, but not yeast polyphosphomannan PPME, inhibits leukocyte rolling in venules of the rat mesentery 总被引:11,自引:3,他引:11
Leukocyte rolling in venules is inhibited by several sulfated polysaccharides, by antibodies to the leukocyte adhesion receptor L- selectin (LECAM-1), and by recombinant soluble L-selectin. The sulfated fucose polymer fucoidin and the polyphosphomannan PPME bind to L- selectin and inhibit L-selectin-mediated lymphocyte adhesion to lymph node high endothelial venules (LN-HEV). We investigated whether fucoidin and PPME also inhibit leukocyte rolling. Rolling leukocyte flux was determined by intravital microscopy in 47 venules (diameter 21 to 50 microns) of the rat mesentery with and without micro-infusion of each reagent through 8-microns glass micropipettes. Micro-infusion (1 mg/mL) or intravenous (IV) injection (25 mg/kg) of fucoidin, but not vehicle, reduced leukocyte rolling by greater than 90%. The half- effective concentration was approximately 2.5 micrograms/mL. Stroboscopic fluorescence video microscopy showed that fucoidin decreased the fraction of rolling leukocytes from 44% of all leukocytes passing the venules in control to less than 1%. PPME micro-infusion (1 mg/mL) or IV injection (14 mg/kg) did not reduce leukocyte rolling. Hence, leukocyte rolling differs from lymphocyte homing with respect to the effect of PPME. This may be related to fucoidin binding to L- selectin with greater affinity than PPME. Alternatively, inflamed venular endothelium may express a ligand for L-selectin different from that constitutively expressed on LN-HEV. 相似文献
26.
27.
The aim of this case report was to present a case of multiple calcified tuberculous lymph nodes found on a panoramic radiograph coincidently diagnosed in an endodontic clinic. A detailed discussion on the differential diagnosis of similar such calcification found in the same region is also presented. A 14‐year‐old girl was referred to our department with the complaint of painless swelling in the left side of the lower jaw. Clinical and radiographical examinations were performed, leading to the initial diagnosis of chronic periapical abscess. The patient's medical history was re‐evaluated. Advanced imaging and excisional biopsy were performed in order to confirm the final diagnosis. Regarding the presenting signs and symptoms of bilateral carious mandibular molars, a periapical inflammatory process was considered in the provisional diagnosis. A thorough examination and investigations were suggestive of cervical tuberculous lymphadenitis (scrofula), and the patient underwent excision of the same. The clinician should consider the possibility of chronic granulomatous inflammatory lesions in the differential diagnosis of radiopaque lesions. 相似文献
28.
29.
Louise Staley-Gane Linda Flynn Kari Neitzel Amy Cronister Randi J. Hagerman 《American journal of medical genetics. Part A》1996,64(2):382-387
The basic components of genetic counseling are informational and educational. The patient's cognitive and emotional presentation and the needs and concerns of the patient are seldom addressed. Females who carry the FMR1 pre and full gene mutation may present with learning, cognitive, and/or emotional difficulties and family members of those diagnosed with fragile X syndrome have ongoing needs and concerns. As a result, genetic counseling for fragile X syndrome offers a unique opportunity within which to expand the role of the genetic counselor. Q-methodology, by using the q-sort, is centered on the family to reproduce the needs and concerns that are consistent with the patient's own experience. Used for sociological research, the q-methodology with specially constructed q-sort items is easily adapted to the genetic counseling setting © 1995 Flynn & Gane and can be used for directly assessing the patient's needs and concerns. For our pilot study, 16 items were physically sorted and ranked interdependently by the patient (subject). Thirty-seven patients (29 females and 8 males) participated in our pilot study. Preliminary results show that the age of the proband, length of time of the diagnosis, and parental sex at the time the q-sort is administered impacts the ranking of items thus differentiating needs and concerns. Results have shown that specific items are missing from the lives of subjects. From the information obtained from the q-sort, the genetic counselor can identify needs and concerns of the patient and combine this information with the clinical presentation to work with the patient in a more effective manner. © 1996 Wiley-Liss, Inc. 相似文献
30.