全文获取类型
收费全文 | 2231篇 |
免费 | 117篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 29篇 |
儿科学 | 160篇 |
妇产科学 | 64篇 |
基础医学 | 234篇 |
口腔科学 | 38篇 |
临床医学 | 197篇 |
内科学 | 319篇 |
皮肤病学 | 55篇 |
神经病学 | 158篇 |
特种医学 | 49篇 |
外科学 | 252篇 |
综合类 | 93篇 |
预防医学 | 114篇 |
眼科学 | 42篇 |
药学 | 279篇 |
中国医学 | 17篇 |
肿瘤学 | 250篇 |
出版年
2023年 | 13篇 |
2022年 | 48篇 |
2021年 | 96篇 |
2020年 | 39篇 |
2019年 | 57篇 |
2018年 | 61篇 |
2017年 | 46篇 |
2016年 | 72篇 |
2015年 | 72篇 |
2014年 | 90篇 |
2013年 | 98篇 |
2012年 | 130篇 |
2011年 | 159篇 |
2010年 | 73篇 |
2009年 | 57篇 |
2008年 | 91篇 |
2007年 | 82篇 |
2006年 | 84篇 |
2005年 | 72篇 |
2004年 | 81篇 |
2003年 | 60篇 |
2002年 | 58篇 |
2001年 | 41篇 |
2000年 | 47篇 |
1999年 | 46篇 |
1998年 | 18篇 |
1996年 | 14篇 |
1995年 | 10篇 |
1994年 | 15篇 |
1992年 | 29篇 |
1991年 | 18篇 |
1990年 | 31篇 |
1989年 | 30篇 |
1988年 | 35篇 |
1987年 | 30篇 |
1986年 | 32篇 |
1985年 | 30篇 |
1984年 | 25篇 |
1983年 | 27篇 |
1979年 | 24篇 |
1977年 | 13篇 |
1976年 | 9篇 |
1974年 | 22篇 |
1973年 | 9篇 |
1972年 | 16篇 |
1971年 | 17篇 |
1970年 | 12篇 |
1969年 | 11篇 |
1968年 | 16篇 |
1967年 | 15篇 |
排序方式: 共有2350条查询结果,搜索用时 15 毫秒
1.
2.
In contrast with cross-sectional designs used in previous studies, this exploratory study compared survey data from 127 matched pairs of clinical pharmacists and physicians working together. Physicians' perceptions of the importance of clinical pharmacy activities for patient care and the competence of pharmacists performing the activities were examined for their influence on prescribing behavior in an institutional setting. Data from a national survey showed that physicians rated pharmacists higher regarding recommendations based on drug use evaluations (p = 0.004) and competency to provide all clinical pharmacy services. Scores for pharmacokinetics ratings were similar between pharmacists and physicians (p = 0.168). Pharmacists rated the importance of recommendations based on cost-effectiveness higher than physicians (p = 0.012). Overall, physicians' perceptions of activity importance for patient care and pharmacist competency appear to dictate pharmacists' influence on physician prescribing behavior (R = 0.723). 相似文献
3.
4.
5.
Karyotypes of 36 lymphoblastoid cell lines established by Epstein-Barr virus (EBV) transformation of peripheral blood lymphocytes (PBL) of eight normal individuals and 28 patients with various nonhematologic malignancies were analyzed. In seven lines (19.4%), cells with trisomy 12 were noted, with clonality in two of these lines. In two of 11 metaphases with such trisomy, chromosome 12 was involved in structural rearrangements [t(8;12)(q12;p12) and t(12;12)(q11;q24)]. No cells with trisomy 12 were observed in phytohemagglutinin (PHA)-stimulated PBL cultures of these individuals. In 250 individuals (normal and with nonhematologic malignancies) examined in our laboratory in the last 5 years, extra copies of chromosome 12 in PHA-stimulated PBL cultures were observed in only five of 23,216 cells (0.02%). There were no cases of clonality in these samples. The frequency of an extra chromosome 12 was comparable to that of the other chromosomes except 21 and X, whose frequency of occurrence was 0.08% and 0.09%, respectively. These findings should be considered random events in PHA-stimulated PBL. On the contrary, in lymphoblastoid cell lines established by EBV transformation, trisomy of chromosome 12 was the most frequent numerical abnormality. It was observed in 64.7% of all cases with chromosome gains and therefore could not be considered a random occurrence. The specificity of this phenomenon for EBV transformation is supported by the results of cytogenetic analysis of eight lymphoblastoid cell lines established by an alternative procedure in our laboratory [1]. In 400 cells analyzed not a single cell with trisomy 12 was observed. We suggest that EBV transformation might either randomly induce formation of such cells in immortalized B-cell populations or show potentially blastomogenic cells or proneness to their formation in certain individuals who could be predisposed to develop lymphoproliferative diseases, especially chronic lymphocytic leukemia (CLL) in which trisomy of chromosome 12 is the most common alteration. 相似文献
6.
The genomic activity of nucleolar organizer regions (NORs) in eight human B-cell lymphoblastoid cell lines was studied following the routinely used Ag-NOR technique. The results demonstrate that (a) Ag-NORs are located in the short arms of D- and G-group chromosomes, (b) two out of eight cell lines have 66.7% and 49.0% of metaphases, respectively, with 9 to 10 active Ag-NORs, and (c) as a whole, Ag-NOR activity is much higher in B-cell lines as compared with conventional 72-hr peripheral blood lymphocyte (T-cell) harvests. 相似文献
7.
Transformation of immortal, non-tumorigenic osteoblast-like human osteosarcoma cells to the tumorigenic phenotype by nickel sulfate 总被引:5,自引:2,他引:3
Rani A.Shobha; Qu Da-Qin; Sidhu Maninder K.; Panagakos Fotinos; Shah Varsha; Klein Kenneth M.; Brown Nicholas; Pathak Sen; Kumar Suriender 《Carcinogenesis》1993,14(5):947-953
Epidemiological studies have indirectly linked compounds ofchromium, nickel and arsenic to human carcinogenesis. However,there is no evidence that metal compounds can transform humancells to the tumorigenic phenotype in culture. We show herethat exposure to 36 µM NiS04 for 4896 h resultsin transformation of an immortal, non-tumorigenic, osteoblast-likecell line, HOS TE85, to the tumorigenic phenotype. Continuouspassaging following treatment leads to the formation of a fewdense foci. The cells isolated and expanded from the foci aremorphologically transformed, and form anchorage-independentcolonies of the size and abundance comparable to that formedby Kirsten murine sarcoma virus transformed HOS TE85 cells.The transformed cells from tumors in nude mice, have enhancedlevels of plasminogen activators and have lost the ability toform model bone matrix on extended culture in the presence ofascorbic acid and ß-glycerophosphate. A number ofcell lines have been established from nude mouse tumors. Cytogeneticanalysis reveals 16 marker chromosomes and an aberrant chromosome16. This is the first report of the transformation of a humancell line to tumorigenic phenotype by a metal carcinogen. 相似文献
8.
Garima Chawla Piyush Gupta R Thilagavathi Asit K Chakraborti Arvind K Bansal 《European journal of pharmaceutical sciences》2003,20(3):305-317
This study deals with the generation and characterization of various solid-state forms of celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor. The drug was subjected to polymorphic screen using different solvents to explore the possibility of existence of different solid forms. N,N-Dimethyl acetamide (DMA) and N,N-dimethyl formamide (DMF) yielded solvates in 1:1 stoichiometric ratio. Quench cooling of the melt resulted in amorphous form of the drug. All these solid-state forms were characterized by thermoanalytical (DSC, TGA, HSM), crystallographic (XRD), microscopic (polarized, SEM), spectroscopic (FTIR), and elemental analysis techniques. Solubility and van't Hoff studies were carried out for their thermodynamic interpretation. Influence of morphology of different solid-state forms on flow behavior was also investigated. Molecular modeling studies were used to elucidate the interaction between solute and solvent molecules in the solvate. 相似文献
9.
Prevalence of benign, atypical, and malignant breast lesions in populations at different risk for breast cancer. A forensic autopsy study 总被引:6,自引:0,他引:6
A forensic autopsy series of 519 women more than 14 years old was studied for prevalence of benign, atypical, and occult malignant breast lesions. The women included Anglos (non-Hispanic whites), Hispanics, and American Indians from New Mexico and Eastern Arizona. These three ethnic/racial groups are at markedly different risk for the development of breast cancer (Anglo 89 of 100,000 women per year, Hispanic 45.5, and American Indian 24.9. There were striking ethnic/racial and age-related differences in both the prevalence and magnitude of all forms of nonproliferative and proliferative fibrocystic disease. The various subsets of fibrocystic disease were highly associated with each other. Such lesions as apocrine metaplasia, sclerosing adenosis, and lobular microcalcification showed as much difference according to ethnic/racial background and age as the more common cystic change and duct epithelial hyperplasia. Atypical lobular and ductal hyperplasia, carcinoma in situ, and occult invasive carcinoma were uncommon and also occurred in ethnic/racial groups in a pattern that parallels the cancer risk in those groups. 相似文献
10.
Sen Pathak 《Cancer Genetics and Cytogenetics》1980,1(3):281-289
Cytogenetic analysis using C-, G-, and Ag-nucleolus organizer region (NOR) staining techniques, performed on established cell lines as well as directly processed breast tumor effusions, revealed that: 1) chromosome No. 1 is involved in translocation; 2) based on 1q translocation chromosome, breast tumors could be classified into two groups; and 3) double minutes and homogeneously staining regions may be present in breast tumor cells in vivo as well as in vitro, and that homogeneously staining regions may exhibit some heterogeneity in staining. 相似文献