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排序方式: 共有165条查询结果,搜索用时 15 毫秒
1.
吡酮酸类抗菌药物的研究Ⅷ.1-对氟苯基-6-氟-1,4-二氢-4-氧-7-(1-哌嗪)噌啉-3-羧酸及其类似物的合成和构效关系 总被引:1,自引:0,他引:1
为探讨构效关系,合成了1-对氟苯基-6-氟-1,4-二氢-4-氧-7-(1-哌嗪)噌啉-3-羧酸及其喹啉、萘啶、吡啶[2,3-C]哒嗪环系类似物16个。测定了对大肠杆菌的MIC。用Hückel分子轨道理论(HMO)方法计算了四个母体环上电子密度。结果表明:环中氮的位置对药效团——3位羧基和4位羰基氧原子上电子密度的影响较大而影响其抗菌活性。喹啉、萘啶两环系的3位羧基和4位羰基氧原子上的电子密度较高,其体外抗菌活性较高;而噌啉及吡啶[2,3-C]哒嗪两环系的电子密度较低,其体外抗菌活性较低甚至消失。 相似文献
2.
P. F. Cavanaugh J. S. Mcdonald L. Pavelic R. J. Limardi J. L. Gluckman Z. P. Pavelic 《Inflammopharmacology》1995,3(2):109-119
Prostaglandins are inflammatory mediators that are believed to play an important role in the pathophysiology of periodontal
disease. Prostaglandin H synthase (PGHS, EC 1.14.99.1) is the rate-limiting enzyme in prostaglandin biosynthesis. The enzyme
exists as two separately encoded isoforms. PGHS-1 which is constitutively expressed and PGHS-2 which is induced by inflammatory
stimuli. This is the first report describing the expression of the isoenzymes in gingival tissue from patients diagnosed with
adult periodontitis. Tissue was fixed in an alcohol-based fixative and embedded in paraffin. Methods were developed using
immunohistochemical controls, such that embedded sections could be processed and stained using isoform-specific antibodies
and a peroxidase-antiperoxidase immunohistochemistry technique. Along with populations of mononuclear inflammatory cells,
endothelial cells and fibroblasts, the gingival epithelial cell layer appears to be a rich and important source of prostaglandin
production within the periodontium of patients with periodontitis as detected by this newly developed immunohistochemical
staining technique for PGHS-1 and PGHS-2. 相似文献
3.
Van de Velde H; De Vos A; Joris H; Nagy ZP; Van Steirteghem AC 《Human reproduction (Oxford, England)》1998,13(11):3160-3164
In human in-vitro fertilization (IVF), the oocytes are surrounded by
cumulus and corona cells at the time of insemination so that their maturity
cannot easily be evaluated. The best IVF results are obtained if the
oocytes are inseminated 2-6 h after retrieval. In the intracytoplasmic
sperm injection (ICSI) procedure, the oocytes are denuded by enzymatic and
mechanical treatment in order to be able to perform the injection. As a
consequence, the nuclear maturity of the oocytes can be evaluated and only
those that have extruded the first polar body are injected. However,
metaphase-II oocytes that have not yet reached cytoplasmic maturity cannot
be recognized. The purpose of this study was to investigate the effect of
different timing of cumulus- corona cell removal and injection on the
outcome of ICSI. For this we allowed the oocytes to complete in-vitro
cytoplasmic maturation in two different culture conditions: (i) surrounded
by their cumulus and corona cells or (ii) totally denuded. We performed
three different studies on sibling oocytes obtained after a standardized
buserelin/human menopausal gonadotrophin (HMG) protocol. We investigated
the effect of early (1-2 h after retrieval) and late (5-6 h after
retrieval) oocyte denudation and injection on the survival and
fertilization of the injected oocytes and on embryo cleavage after
fertilization. We found no statistically significant differences between
early and late injection, indicating that after a standardized
buserelin/HMG protocol the metaphase-II oocytes do not need time for
further cytoplasmic maturation. Furthermore, a different timing of
cumulus-corona cell removal has no effect on the outcome of ICSI,
suggesting that the surrounding cells are not necessary for survival,
fertilization and cleavage after ICSI.
相似文献
4.
Percoll gradient centrifugation can be omitted in sperm preparation for intracytoplasmic sperm injection 总被引:4,自引:3,他引:4
De Vos A; Nagy ZP; Van de Velde H; Joris H; Bocken G; Van Steirteghem A 《Human reproduction (Oxford, England)》1997,12(9):1980-1984
Prior to intracytoplasmic sperm injection (ICSI), seminal fluid is
currently washed out from the ejaculated semen and further sperm selection
is carried out by a discontinuous Percoll gradient. Possible deleterious
effects from the sperm-separating substance Percoll on sperm function or
embryo cleavage after in-vitro fertilization (IVF) have, to our knowledge,
not yet been reported and the use of Percoll has been widely accepted in
IVF. In this study, we examined whether the omission of the Percoll step in
the sperm preparation has any influence on the outcome of the ICSI
procedure. Two methods of sperm preparation for ICSI were compared in a
controlled study on sibling oocytes: washing the semen sample once,
followed by a Percoll gradient centrifugation versus washing the sperm
sample twice without a Percoll gradient centrifugation. The mean
fertilization rates were similar for the two sperm preparation methods:
78.2 +/- 21.4 and 75.0 +/- 24.1% respectively of the intact oocytes
displaying two pronuclei. Cleavage rates did not differ statistically
between the two groups. Whereas in both groups similar percentages of
excellent, good and poor quality embryos were obtained, the percentage of
fair quality embryos was significantly higher in the group without Percoll
(16.3 +/- 20.1 versus 9.1 +/- 15.7%). However, no statistical differences
were observed in either the percentage of transferable embryos or in the
percentage of embryos actually transferred or frozen in the two groups. In
conclusion, spermatozoa from ejaculates that are washed out from the
seminal fluid without any further selection can be used for ICSI without
any adverse effect on fertilization and embryo cleavage.
相似文献
5.
Gurtoo H.L.; Koser P.L.; Bansal S.K.; Fox H.W.; Sharma S.D.; Mulhern A.I.; Pavelic Z.P. 《Carcinogenesis》1985,6(5):675-678
Effects of ß-naphthonflavoe (ßNF) on theactivity of hepatic microsomal aflatoxin B1 (AFB1)-4-hydroxylase- the cytochrome P-450-dependent enzyme system which catalyzesthe metabolism of AFB1 to AFM1 - and on AFB1 induced in vivohepatocarcinogenesis were investigated in weanling male Fischerrats. A single i.p. injection of ßNF in doses of 20mg/kg and 150 mg/kg induced AFB1 -4-hydroxylase 3- and 4-fold,respectively, 48 h post injection. Feeding of diet containing0.01% ßNF for a period of 9-weeks induced AFB1 2-fold.AFB1, given by intubatlon in a dose of 25 µg five times/weekfor 8 weeks, produced 42 weeks later a 100% incidence of liverlesions (neoplastic foci, nodules or tumors), but feeding ßNFin diet at a con centration of 0.015% for one week prior toand during the 8 weeks of AFB treatment inhibited AFB1 hepatocarcinogenesis by -7%. These results are in accord with the suggestionthat AFB1 induction may be associated with the inhibition ofAFB1 carcinogenesis, possibly occurring as a consequence ofaccelerated detoxi-fication of AFB1 via its conversion to AFM1 相似文献
6.
McDonald JS Gartside PS Pavelic LJ Gluckman JL Pavelic ZP 《Pathology oncology research : POR》1996,2(1-2):34-36
Archival material from 47 patients with primary squamous cell carcinoma of the head and neck (SCCHN) was studied immunohistochemically
for the presence of nm23-H1 protein. Our data indicate that nm23-H1 protein expression is a common event in SCCHN and that
there is a trend toward correlation of increased expression of nm23-H1 with increasing tumor size (p = 0.072). The results
also show that when adjusting for age and cause of death, there tended to be an inverse relationship between overall survival
and the expression of nm23-H1 gene in the primary tumor (p = 0.088). 相似文献
7.
Bozo Kruslin Reno Hrascan Spomenka Manojlovic Kresimir Pavelic 《Fetal and pediatric pathology》1997,17(1):43-52
Congenital sacrococcygeal teratoma SCT is the most common germ cell tumor of infancy and childhood with a female preponderance. Most SCTs are diagnosed at birth, are benign, and consist of fully differentiated, mature tissues. Tumorigenesis of SCTs remains poorly understood. Almost nothing is known about possible oncogene activation or tumor suppressor inactivation in these rare tumors. We describe the presence of various oncoproteins and tumor suppressor proteins in eight cases of congenital SCT. The following oncogenes were examined: ras family c-H-, c-N-, and c-K-ras , early genes fos, jun , and tumor suppressor genes p53 and nm23-H-1 . There was no relationship between the intensity of expression of these oncoproteins and tumor suppressor genes and the following parameters: tumor size, age, and survival of the patients. We did not observe any difference, however, between the expression of the examined oncogenes and tumor suppressor genes nm23 and p53 in immature and mature teratomas. Our findings suggest that the ras family of oncogenes, fos and jun oncogenes, and nm23 and p53 tumor suppressor genes are present in congenital SCT, indicating a possible role in genesis and development of these tumors. 相似文献
8.
Jack L. Gluckman Zlatko P. Pavelic Hans-Jurgen Welkoborsky Wolf Mann Peter Stambrook Lyon Gleich Keith Wilson Paul Righi Louis G. Portugal John McDonald Paul Biddinger David Steward Peter Gartside 《The Laryngoscope》1997,107(9):1239-1244
Fifty-three patients with T1 squamous cell cancer of the floor of mouth and ventral surface of the tongue with a known clinical outcome were retrospectively analyzed and arbitrarily divided into “aggressive” and “nonaggressive” groups based on their clinical behavior. Various host and tumor factors were then evaluated in an attempt to determine whether the tumor behavior could have been predicted. The paraffin-embedded tumor specimens were evaluated for tumor differentiation, tumor thickness and tumor invasion, microvessel density, and p53 expression. In addition, a composite morphologic grading score was obtained by combining cell differentiation, nuclear polymorphism, mitosis activity, depth of infiltration, type of infiltration, and lymphatic infiltration. No single technique appeared capable of identifying “aggressive” behavior, although possibly an evaluation of composite factors might show promise in the future. 相似文献
9.
Correlation of tumor-cell growth in four semisolid systems 总被引:1,自引:0,他引:1
Z. P. Pavelic N. J. Nowalk H. K. Slocum Y. M. Rustum 《Journal of cancer research and clinical oncology》1983,105(1):94-97
The correlation of the colony growth of cells disaggregated from human melanoma, sarcoma, lung, and ovarian carcinomas were studied in four different semisolid tissue culture assays: (a) the soft agar assay of Pluznik and Sachs; (b) the soft agar assay of Hamburger and Salmon; (c) the soft agar-methyl cellulose assay of Buick et al.; and (d) the methyl cellulose assay of Ogawa et al. There was no colony growth of tumor cells achieved in 15 of 15 cases assayed in Ogawa's methyl cellulose assay. The plating efficiency of the above mentioned tumors was similar in the assays of Pluznik and Sachs, Hamburger and Salmon, and Buick et al. However, the tumor take rate differed among these three systems. The assay of Buick et al. appears potentially useful for analysis of the biology of human tumors. 相似文献
10.
Zlatko P. Pavelic Nicholas J. Petrelli Lemuel Herrera Mary M. Vaughan Jeffrey S. Paecock Ljiljana Pavelic 《Journal of cancer research and clinical oncology》1990,116(1):51-56
Summary The reactivity of D-14 monoclonal antibody (mAb) to a specific epitope of carcinoembryonic antigen (CEA) was evaluated on formalin-fixed, paraffin-embedded tissues. A total of 52 normal tissues, 90 colorectal carcinomas and 127 non-colorectal neoplasms were tested using the peroxidase/antiperoxidase technique. D-14 mAb did not react with normal tissues apart from producing a weak staining of normal colonic glands immediately adjacent to the neoplastic structures. All 61 primary and 29 metastatic colorectal carcinomas expressed the carcinoembryonic antigen. However, there was considerable heterogeneity in cellular antigen expression in both primary and metastatic colorectal carcinomas with 10%–99% of tumor cells staining. Of 22 stomach adenocarcinomas, 14 were also immunoreactive, as were 2 of 5 pancreatic carcinomas. Only 6 of 100 neoplasms of non-gastrointestinal origin expressed weak to moderate immunoreactivity. In 7 cases, colorectal micrometastases not recognized in conventional hematoxylin and eosin slides could be identified with D-14 mAb. The specificity of this antibody could be used in differentiating colorectal carcinomas from other types of tumors, including adenocarcinoma from other sites.This paper was presented at the 1989 Annual Meeting of the American Association for Cancer Research Inc., San Francisco, California 相似文献