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排序方式: 共有208条查询结果,搜索用时 15 毫秒
41.
We present a PCR procedure for identification of Burkholderia cepacia, Burkholderia multivorans, and Burkholderia vietnamiensis. 16S and 23S ribosomal DNAs (rDNAs) of B. multivorans and B. vietnamiensis were sequenced and aligned with published sequences for definition of species-specific 18-mer oligonucleotide primers. Specific antisense 16S rDNA primers (for B. cepacia, 5'-AGC ACT CCC RCC TCT CAG-3'; for B. multivorans, 5'-AGC ACT CCC GAA TCT CTT-3') and 23S rDNA primers (for B. vietnamiensis, 5'-TCC TAC CAT GCG TGC AA-3') were paired with a general sense primer of 16S rDNAs (5'-AGR GTT YGA TYM TGG CTC AG-3') or with a sense primer of 23S rDNA (5'-CCT TTG GGT CAT CCT GGA-3'). PCR with these primers under optimized conditions is appropriate to specifically and rapidly identify B. multivorans, B. vietnamiensis, and B. cepacia (genomovars I, III, and IV are not discriminated). In comparison with the polyphasic taxonomic analyses presently necessary for species and genomovar identification within the B. cepacia complex, our procedure is more rapid and easier to perform and may contribute to clarifying the clinical significance of individual members of the complex in cystic fibrosis.  相似文献   
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43.
Doxorubicin (DOX) and its daunosamine-modified derivative, 2-pyrrolino-DOX, which is 500-1000 times more active than DOX, were incorporated into agonistic and antagonistic analogs of luteinizing hormone-releasing hormone (LH-RH). The conjugation of DOX with LH-RH analogs was performed by using N-(9-fluorenylmethoxycarbonyl)-DOX-14-O-hemiglutarate, a dicarboxylic acid ester derivative of DOX. Coupling this derivative covalently to the epsilon-amino group of the D-Lys side chain of agonist [D-Lys6]LH-RH or antagonistic analog AC-D-Nal(2)-D-Phe(4Cl)-D-Pal(3)-Ser-Tyr-D-Lys-Leu-Arg-Pro-D-Ala-NH 2 [where Nal(2) = 3-(2-naphthyl)alanine, Pal(3) = 3-(3-pyridyl)alanine, and Phe(4CI) = 4-chlorophenylalanine] was followed by the removal of the 9-fluorenylmethoxycarbonyl protective group to yield cytotoxic derivatives of LH-RH analogs containing DOX. From these DOX containing LH-RH hybrids, intensely potent analogs with daunosamine-modified derivatives of DOX can be readily formed. Thus, cytotoxic LH-RH agonist containing DOX (AN-152) can be converted in a 66% yield by a reaction with a 30-fold excess of 4-iodobutyraldehyde in N,N-dimethylformamide into a derivative having 2-pyrrolino-DOX (AN-207). Hybrid molecules AN-152 and AN-207 fully preserve the cytotoxic activity of their radicals, DOX or 2-pyrrolino-DOX, respectively, in vitro, and also retain the high binding affinity of the peptide hormone portion of the conjugates to rat pituitary receptors for LH-RH. These highly potent cytotoxic analogs of LH-RH were designed as targeted anti-cancer agents for the treatment of various tumors that possess receptors for the carrier peptide. Initial in vivo studies show that the hybrid molecules are much less toxic than the respective cytotoxic radicals incorporated and significantly more active in inhibiting tumor growth.  相似文献   
44.
Summary Salmonella typhimurium strains resistant to most -lactams, co-trimoxazole, tobramycin and gentamicin were isolated from patients in two hospitals in Buenos Aires, Argentina, beginning in August 1990. The patients were suffering from meningitis, septicaemia or enteritis. Therapy including ampicillin, ceftriaxone and gentamicin failed. The strains produced a plasmidic (pMVP-4) extended broad-spectrum -lactamase which is more active against cefotaxime than against ceftazidime (Vmax for cefotaxime 350 times higher than for ceftazidime). This cefotaximase demonstrates similarity to the previously described CTX-ase-M-1 fromEscherichia coli, but it is distinctly different from CTX-ase-M-1 by its isoelectric point (7.9 for CTX-ase-M-2 in comparison with 8.9 for CTX-ase-M-1) as well as in its lower susceptibility to the -lactamase inhibitors sulbactam, clavulanic acid, tazobactam and BRL 42715. Thus, the -lactamase produced byS. typhimurium strains from Argentina appears to represent a new member (CTX-ase-M-2) of a novel group of plasmidic extended broad-spectrum -lactamases designated as cefotaximases.
Neue plasmidische Cefotaximase von Patienten mit Salmonella typhimurium-Infektion
Zusammenfassung In zwei Hospitälern in Buenos Aires, Argentinien, wurden von August 1990 anSalmonella typhimurium-Stämme mit Resistenz gegenüber den meisten -Laktamantibiotika, Co-trimoxazol sowie Tobramycin und Gentamicin isoliert. Klinische Diagnosen bei diesen Patienten waren Meningitis, Sepsis oder Enteritis. Antibiotische Therapie mit Ampicillin, Ceftriaxon und Gentamicin blieb erfolglos. DieS. typhimurium-Stämme produzieren eine plasmidische (Plasmid pMVP-4) -Laktamase mit erweitertem Breitspektrum (EBS--Lactamase), welche gegenüber Cefotaxim deutlich aktiver ist als gegenüber Ceftazidim (Vmax für Cefotaxim 350 mal größer als für Ceftazidim). Diese Cefotaximase ist verwandt mit der Cefotaximase ausEscherichia coli (CTX-M-1), von der sie sich jedoch im isoelektrischen Punkt (7,9 bei der CTX- ase-M-2 gegenüber 8,9 bei der CTX-ase-M-1) sowie in ihrer Hemmbarkeit durch Sulbactam, Clavulansäure, Tazobactam und BRL 42715 eindeutig unterscheidet. Die beiS. typhimurium-Stämmen in Argentinien gefundene neue -Laktamase wird als zweites Enzym einer neuen Gruppe von -Laktamasen mit erweitertem Breitspektrum vom Cefotaximase-Typ betrachtet.
  相似文献   
45.
Insulin-like growth factors-I and-II (IGF-I and IGF-II) may be involved in the proliferation of human lung carcinomas. The purpose of this study was to investigate the effects of two potent antagonists of growth hormone-releasing hormone (GH-RH), MZ-4-71 and MZ-5-156 on the growth of the H69 human small cell lung cancer (SCLC) and H157 non-SCLC (NSCLC) lines transplanted into nude mice or cultured in vitro. Nude mice bearing H69 and H157 tumors were treated for 3-5 weeks with MZ-4-71 or MZ-5-156 injected s.c. twice a day at a dose of 20 mu g/animal. Growth of H69 and H157 tumors in nude mice was significantly inhibited by MZ-4-71 and MZ-5-156 as shown by a reduction in tumor volume and weight. In animals bearing H157 NSCLC, treatment with MZ-4-71 decreased IGF-I and IGF-II levels in tumor tissue. Levels of IGF-I, but not of IGF-II in serum and liver tissue of H157 tumor-bearing nude mice treated with MZ-4-71 were decreased. High affinity binding sites for ICF-I were demonstrated on membranes of H69 and H157 tumors. In cell cultures, the proliferation rate of H69 SCLC cells was suppressed by 10(-7)-10(-5) M MZ-4-71, but H157 NSCLC line was only inhibited by 10(-5) M antagonist. Our findings demonstrate that the GHRH antagonists MZ-4-71 and MZ-5-156 can inhibit the growth of SCLC and NSCLC. This new approach to the management of lung cancer merits further investigation.  相似文献   
46.
47.
Background: Age and diabetes mellitus have been identified as independentrisk factors for cognitive decline after cardiac surgery withcardiopulmonary bypass (CPB). We tested the effects of CPB oncognitive function in aged and diabetic rats utilizing the Morriswater maze (MWM). Methods: Aged rats (26 months) were randomized into a sham group (cannulationbut no CPB, n = 11) and a 90 min CPB group (n = 11). In addition,young rats (n = 14) were made diabetic with streptozotocin 9weeks before experimentation and randomized to a sham or 90min CPB group. Cytokine release [interleukin (IL-6)] and short-termMWM performance (days 8–14 after operation) were assessedin all animals. Long-term MWM performance (8 weeks after operation)was assessed in aged rats only. Results: There were no differences between the aged groups in short-term(P = 0.58) or long-term MWM performances (P = 0.69). The diabeticanimals also showed no differences between the sham and CPBgroups in MWM performance (P = 0.64). IL-6 assays showed anincreased inflammatory response after CPB in the diabetic animals,but not in the elderly groups. Conclusions: Ninety minutes of normothermic CPB had no deleterious effecton neurocognitive outcome in elderly or chronically diabeticanimals, suggesting that CPB in itself is not a sufficient stressorof the rat central nervous system.  相似文献   
48.
BACKGROUND: Neurotrophic factors are known to play an important role in the survival and differentiation of many types of neurons during development. Both brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF) may act cooperatively in modulating the development and functioning of synapses. Both these neurotrophic factors were intensely investigated with regard to depression without conclusive results. METHODS: We have investigated the possible use of both CNTF null-mutation and BDNF polymorphism C270T as biomarkers for depression in the Vienna Transdanube Aging (VITA) study. The VITA is a prospective community-based cohort study of all 75 years old inhabitants of a geographical region of Vienna. RESULTS: We found no association between CNTF null-mutation and BDNF C270T polymorphism to any depressive symptoms after exclusion of demented subjects. CONCLUSION: These results call in question the hypothesis that either BDNF or CNTF can be used as molecular markers for depression or late onset depression in the elderly.  相似文献   
49.
Globally, cardiovascular diseases (CVDs) are the number one cause of all mortalities. Of these deaths, 7.6 million are due to heart attacks, and 5.7 millions are due to stroke. The Vienna Transdanube Aging Study (VITA), a population-based cohort study, enabled us to evaluate associations between the known major risk factors for cerebrovascular and CVDs and their appearance beyond age 75 years. Using a single birth cohort, age was excluded as confounding factor. In the baseline investigations in the Danube Hospital, 606 individuals took part and were examined completely at baseline. After 60 months, 508 patients were re-examined. Each participant underwent an indepth investigation with the duration of 7 h, including neuropsychological testing, as well as analyses of biochemical, clinical chemical and genetic parameters, and magnetic resonance imaging (MRI) of the brain. In the present study, only a history of cerebral and cardiovascular events at the baseline or smoking was associated significantly with the appearance of CVDs. In a multiple model both risk factors—history of cerebral and cardiovascular events at the baseline (p = 0.0003, OR 2.36, 95% CI 1.49–3.76) and smoking (p = 0.0005, OR 1.57, 95% CI 1.22–2.03)—remained significant. However, the predictive value of this assessment model was low. The rescaled r 2 of the model was 0.088. A significant correlation was found only between exposure to cigarette smoke or a history of previous CVDs, such as stroke or myocardial infarction. Smoking or earlier CVDs greatly increase the risk for further cerebral and cardiovascular events in persons after 75 years.  相似文献   
50.
BACKGROUND: The prevalence of clinically silent intracranial tumors in specific populations is poorly researched. It is known that, in advanced age groups, the number of clinically manifest meningiomas constitute a small proportion of the actual number of cases. The goals of the current study were to determine the frequency of asymptomatic patients with meningioma in advanced age and to identify risk factors for meningiomas in this population. METHODS: Between May 2000 and November 2002, 532 probands from a specifically defined geographic area of Vienna who were age 75 years underwent a magnetic resonance imaging scan of the brain and were evaluated for the presence of a space-occupying mass. All probands were examined clinically and neurologically as well as by a neuropsychiatrist. The patients' medical histories were carefully documented with regard to previous diseases, medication, and lifestyle, as were their laboratory reports. The collected data were correlated and similarities among subjects with meningioma were determined. RESULTS: Nine meningiomas that were unknown until the time of investigation were observed among the 318 women included in the trial (corresponding to a calculated prevalence of 2800/100,000 clinically silent meningiomas in 75-year-old women). No tumors were found among men. Associated clinical changes or deficits were not observed in any subject. Apart from advanced age and female gender, no other accepted or well known risk factors were observed in the tumor patients. CONCLUSIONS: Clinically quiescent meningiomas in the elderly female population were more common than was believed to be the case to date. Known and influenceable risk factors were found to be less important than age and gender. The high frequency of this lesion should be considered when deciding on the treatment of patients with incidentally discovered, clinically quiescent meningiomas.  相似文献   
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