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71.
Jianguo Ma Marc Maliepaard Herman J. Kolker Jaap Verweij Jan H. M. Schellens 《Cancer chemotherapy and pharmacology》1997,41(3):186-192
The parental IGROV-1 human ovarian adenocarcinoma cell line was intermittently exposed to increasing concentrations of cisplatin
to obtain resistant sublines. A stable resistant subline with a resistance factor of 8.4 had been developed after 9 months
and 28 passages, which was denoted IGROVCDDP. A high correlation coefficient of 0.97 was found between the log cell survival and the DNA-adduct peak level during the
process of resistance development. IGROVCDDP was strongly cross-resistant to carboplatin and doxorubicin and moderately cross-resistant to etoposide, docetaxel, and topotecan.
Only minor resistance against 5-fluorouracil was observed, whereas IGROVCDDP was not cross-resistant to methotrexate. Intracellular accumulation of cisplatin was 65% lower in IGROVCDDP as compared with parental IGROV-1 at 37 °C under normal conditions. Coincubation of cisplatin with the Na+/K+-ATPase inhibitor ouabain resulted in a more pronounced decrease in platinum accumulation in IGROV-1 (44% decrease) than in
IGROVCDDP (26% decrease). Under energy-depleting conditions the accumulation of cisplatin in the parental cell line was approximately
60% lower than that observed under normal (energy [i.e., ATP] rich) culture conditions. In contrast, the accumulation in IGROVCDDP was not affected by ATP-depletion. There appeared to be no significant difference between the intracellular accumulation
of platinum in the resistant and sensitive cells under conditions of energy deprivation or when the uptake was studied at
0 °C. In conclusion, abrogation of energy-dependent accumulation in IGROVCDDP seems to be a major mechanism of resistance to cisplatin in this cell line.
Received: 21 January 1997 / Accepted: 22 July 1997 相似文献
72.
Cognitive disorders in patients with occlusive disease of the carotid artery: a systematic review of the literature 总被引:5,自引:0,他引:5
We present a systematic review of the literature on the prevalence, nature, severity, course, and causes of cognitive deficits
in patients with occlusive disease of the carotid artery prior to surgery (if surgery was under discussion). Searches were
carried out on Medline and Psychlit from 1980 to 1999 using neurovascular and psychological index terms, and papers and books
were checked for further references. Studies describing neuropsychological assessment of groups of patients with carotid obstruction
were included. Eighteen studies were found. We extracted from the papers data on study design, demographic characteristics
of patients, clinical diagnosis, carotid obstruction, cerebral imaging, time interval between ischemic episode and neuropsychological
assessment, neuropsychological asessment procedures, integration and interpretation of test performances, and conclusions
of authors. Fourteen studies concluded that there are cognitive deficits both in patients with symptomatic and in those with
asymptomatic carotid obstruction; four studies denied cognitive impairment. There were no differences in patient characteristics,
study design, or neuropsychological assessment procedures between the 14 studies that found deficits and the 4 that did not.
There are indications for a mild, diffuse, detrimental effect of carotid occlusive disease on cognitive functioning. However,
methodological problems prevent a definitive conclusion. Further research is needed to confirm these findings and to ascertain
the neurovascular risk factors for and the natural course of cognitive impairment in patients with carotid occlusive disease.
Received: 12 July 1999/Received in revised form: 10 November 1999/Accepted: 26 January 2000 相似文献
73.
74.
75.
Association of CYP2C8, CYP3A4, CYP3A5, and ABCB1 polymorphisms with the pharmacokinetics of paclitaxel. 总被引:4,自引:0,他引:4
Anja Henningsson Sharon Marsh Walter J Loos Mats O Karlsson Adam Garsa Klaus Mross Stephan Mielke Lucia Viganò Alberta Locatelli Jaap Verweij Alex Sparreboom Howard L McLeod 《Clinical cancer research》2005,11(22):8097-8104
PURPOSE: To retrospectively evaluate the effects of six known allelic variants in the CYP2C8, CYP3A4, CYP3A5, and ABCB1 genes on the pharmacokinetics of the anticancer agent paclitaxel (Taxol). EXPERIMENTAL DESIGN: A cohort of 97 Caucasian patients with cancer (median age, 57 years) received paclitaxel as an i.v. infusion (dose range, 80-225 mg/m(2)). Genomic DNA was analyzed using PCR RFLP or using Pyrosequencing. Pharmacokinetic variables for unbound paclitaxel were estimated using nonlinear mixed effect modeling. The effects of genotypes on typical value of clearance were evaluated with the likelihood ratio test within NONMEM. In addition, relations between genotype and individual pharmacokinetic variable estimates were evaluated with one-way ANOVA. RESULTS: The allele frequencies for the CYP2C8*2, CYP2C8*3, CYP2C8*4, CYP3A4*3, CYP3A5*3C, and ABCB1 3435C>T variants were 0.7%, 9.2%, 2.1%, 0.5%, 93.2%, and 47.1%, respectively, and all were in Hardy-Weinberg equilibrium. The population typical value of clearance of unbound paclitaxel was 301 L/h (individual clearance range, 83.7-1055 L/h). The CYP2C8 or CYP3A4/5 genotypes were not statistically significantly associated with unbound clearance of paclitaxel. Likewise, no statistically significant association was observed between the ABCB1 3435C>T variant and any of the studied pharmacokinetic variables. CONCLUSIONS: This study indicates that the presently evaluated variant alleles in the CYP2C8, CYP3A4, CYP3A5, and ABCB1 genes do not explain the substantial interindividual variability in paclitaxel pharmacokinetics. 相似文献
76.
L. J. C. van Warmerdam Geert-Jan Creemers S. Rodenhuis Hilde Rosing Maureen de Boer-Dennert Jan H. M. Schellens W. W. ten Bokkel Huinink Brian E. Davies Robert A. A. Maes Jaap Verweij Jos H. Beijnen 《Cancer chemotherapy and pharmacology》1996,38(3):254-260
Topotecan is a novel semisynthetic derivative of the anticancer agent camptothecin and inhibits the intranuclear enzyme topoisomerase
I. The lactone structure of topotecan, which is in equilibrium with the inactive ring-opened hydroxy acid, is essential for
this activity. We performed a pharmacokinetics study as part of phase II clinical trials in patients with various types of
solid tumors, giving topotecan at 1.5 mg/m2 per day by 30-min infusion for 5 consecutive days, with courses being repeated every 3 weeks. Previously validated limited-sampling
models, using concentration measurements in samples obtained 2 h after infusion, were used to calculate the area under the
plasma concentration-time curves (AUCs) for both chemical forms. Samples were obtained from a total of 36 patients over 136
treatment days. The mean AUC of the closed-ring form (AUCclosed) was 8.74 (range 2.3–16.3) μM min per day, and the mean AUC of the ring-opened form (AUCopen) was 11.5 (range 3.2–46.0) μM min per day (interpatient variability 34–61%). In each patient the AUC values achieved on the 1st day of administration were
similar to and, thus, predictive for those achieved during the following days, with a day-to-day variation of 7.39% being
recorded for the AUCclosed and that of 12.6%, for the AUCopen. There was no drug accumulation during the 5 consecutive treatment days of each cycle. However, despite the large interpatient
pharmacokinetic variability, the importance of regular drug monitoring on this schedule can be questioned, as the pharmacodynamic
variability was relatively small.
Received: 15 June 1995/Accepted: 19 October 1995 相似文献
77.
B A Fraass D L McShan R F Diaz R K Ten Haken A Aisen S Gebarski G Glazer A S Lichter 《International journal of radiation oncology, biology, physics》1987,13(12):1897-1908
This paper presents the results of a feasibility study specifically addressing the technical and operational difficulties in making quantitative use of Magnetic Resonance Imaging (MRI) in radiation therapy treatment planning (RTTP). Selected radiotherapy patients have been studied with both CT and MRI as part of the treatment planning process. Both sets of images, along with mechanically-obtained external contour and simulator film data, are entered into the treatment planning system. All of the capabilities of the fully three dimensional planning system U-MPlan are available to both the CT and MRI images, in which any image can be used as the backdrop for interactive beam positioning, beam portal simulation, and dose distribution displays for external beam and brachytherapy applications in both 2- and 3-dimensionally-oriented displays. The study has shown that to use MRI data for RTTP, one must (a) use careful patient positioning and marking, (b) transfer information from CT to MRI and vice versa, (c) determine the geometrical consistency between the CT and MR data sets, (d) investigate the unwarping of distorted MR images, and (e) have the ability to use non-axial images for determination of beam treatment technique, dose calculations, and plan evaluation. 相似文献
78.
Ryo Okamoto Hiroshi Takano Tatsunori Okamura Ji-Seon Park Keiji Tanimoto Takashi Sekikawa Wataru Yamamoto Alex Sparreboom Jaap Verweij Masahiko Nishiyama 《Cancer science》2002,93(1):93-102
The precise mechanisms of resistance to camptothecin (CPT)-derived DNA topoisomerase (topo I) inhibitors and the determinants remain unclear. We found that a DNA repair protein, O6 -methylguanine-DNA methyltransferase(MGMT), participated in resistance to irinotecan hydrochloride (CPT-11), its active metabolite SN-38, and a novel CPT derivative, DX-8951f. In 17 human cancer cell lines, MGMT gene expression level closely correlated with sensitivity to the CPT derivatives, and inhibition of MGMT activity by nontoxic 5 μM O6 -benzylguanine augmented the drug activity in relation to the MGMT expression levels in 8 cell lines examined. Transfection of pCR/MGMT-sense into U-251MG and pCR/MGMT-antisense into T98G and HEC-46 cells revealed that increased MGMT expression decreased the sensitivity to CPT-11, SN-38, and DX-8951f, whereas repressed MGMT expression sensitized cells to the drugs. Western analysis revealed that treatment of MGMT -expressing T98G cells with the drugs caused a decrease of both MGMT and topo I in a dose-dependent manner. Although, in the transfectants, MGMT expression did not so closely correlate with the sensitivity to drugs as to nimustine hydrochloride (ACNU), MGMT is probably an important resistance determinant to CPT derivatives, and may play some role in the topo I-mediated DNA damage and/or the repair process. 相似文献
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80.