全文获取类型
收费全文 | 7733篇 |
免费 | 465篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 53篇 |
儿科学 | 112篇 |
妇产科学 | 150篇 |
基础医学 | 1082篇 |
口腔科学 | 322篇 |
临床医学 | 747篇 |
内科学 | 1754篇 |
皮肤病学 | 158篇 |
神经病学 | 677篇 |
特种医学 | 239篇 |
外科学 | 1172篇 |
综合类 | 50篇 |
一般理论 | 4篇 |
预防医学 | 443篇 |
眼科学 | 161篇 |
药学 | 670篇 |
中国医学 | 19篇 |
肿瘤学 | 435篇 |
出版年
2023年 | 64篇 |
2022年 | 138篇 |
2021年 | 175篇 |
2020年 | 119篇 |
2019年 | 161篇 |
2018年 | 154篇 |
2017年 | 167篇 |
2016年 | 176篇 |
2015年 | 203篇 |
2014年 | 289篇 |
2013年 | 291篇 |
2012年 | 508篇 |
2011年 | 524篇 |
2010年 | 280篇 |
2009年 | 272篇 |
2008年 | 485篇 |
2007年 | 472篇 |
2006年 | 464篇 |
2005年 | 467篇 |
2004年 | 403篇 |
2003年 | 413篇 |
2002年 | 361篇 |
2001年 | 99篇 |
2000年 | 69篇 |
1999年 | 73篇 |
1998年 | 96篇 |
1997年 | 78篇 |
1996年 | 72篇 |
1995年 | 56篇 |
1994年 | 50篇 |
1993年 | 35篇 |
1992年 | 47篇 |
1991年 | 52篇 |
1990年 | 42篇 |
1989年 | 50篇 |
1988年 | 40篇 |
1987年 | 42篇 |
1986年 | 32篇 |
1985年 | 32篇 |
1984年 | 33篇 |
1983年 | 38篇 |
1982年 | 33篇 |
1981年 | 29篇 |
1979年 | 18篇 |
1972年 | 17篇 |
1970年 | 16篇 |
1967年 | 17篇 |
1934年 | 16篇 |
1933年 | 20篇 |
1932年 | 18篇 |
排序方式: 共有8248条查询结果,搜索用时 15 毫秒
81.
Revicki DA Brown RE Palmer W Bakish D Rosser WW Anton SF Feeny D 《PharmacoEconomics》1995,8(6):524-540
The aim of this study was to estimate the cost effectiveness of nefazodone compared with imipramine or fluoxetine in treating women with major depressive disorder. Clinical decision analysis and a Markov state-transition model were used to estimate the lifetime health outcomes and medical costs of 3 antidepressant treatments. The model, which represents ideal primary care practice, compares treatment with nefazodone to treatment with either imipramine or fluoxetine. The economic analysis was based on the healthcare system of the Canadian province of Ontario, and considered only direct medical costs. Health outcomes were expressed as quality-adjusted life years (QALYs) and costs were in 1993 Canadian dollars ($Can; $Can1 = $US0.75, September 1995). Incremental cost-utility ratios were calculated comparing the relative lifetime discounted medical costs and QALYs associated with nefazodone with those of imipramine or fluoxetine. Data for constructing the model and estimating necessary parameters were derived from the medical literature, clinical trial data, and physician judgement. Data included information on: Ontario primary care physicians' clinical management of major depression; medical resource use and costs; probabilities of recurrence of depression; suicide rates; compliance rates; and health utilities. Estimates of utilities for depression-related hypothetical health states were obtained from patients with major depression (n = 70). Medical costs and QALYs were discounted to present value using a 5% rate. Sensitivity analyses tested the assumptions of the model by varying the discount rate, depression recurrence rates, compliance rates, and the duration of the model. The base case analysis found that nefazodone treatment costs $Can1447 less per patient than imipramine treatment (discounted lifetime medical costs were $Can50,664 vs $Can52,111) and increases the number of QALYs by 0.72 (13.90 vs 13.18). Nefazodone treatment costs $Can14 less than fluoxetine treatment (estimated discounted lifetime medical costs were $Can50,664 vs $Can50,678) and produces slightly more QALYs (13.90 vs 13.79). In the sensitivity analyses, the cost-effectiveness ratios comparing nefazodone with imipramine ranged from cost saving to $Can17,326 per QALY gained. The cost-effectiveness ratios comparing nefazodone with fluoxetine ranged from cost saving to $Can7327 per QALY gained. The model was most sensitive to assumptions about treatment compliance rates and recurrence rates. The findings suggest that nefazodone may be a cost-effective treatment for major depression compared with imipramine or fluoxetine. The basic findings and conclusions do not change even after modifying model parameters within reasonable ranges. 相似文献
82.
J. Atzpodien H. Kirchner S. Duensing E. Lopez Hänninen A. Franzke J. Buer M. Probst P. Anton H. Poliwoda 《World journal of urology》1995,13(3):174-177
Summary We conducted a phase I/II clinical trial evaluating the sequential outpatient combination of S.C. recombinant human interleukin-2 (rIL-2; given at 10 MIU/m2 b.i.d. on days 3–5 of weeks 1 and 4 and at 5 MIU/m2 on days 1, 3, and 5 of weeks 2 and 3), s.c. recombinant human alpha-interferon (rIFN-; given at 6 MIU/m2 on day 1 of weeks 1 and 4 and on days 1, 3, and 5 of weeks 2 and 3 and at 9 MIU/m2 on days 1, 3, and 5 of weeks 5–8), i.v. bolus 5-fluorouracil (5-FU; given at 1,000 mg/m2 once weekly during weeks 5–8), and i.v. bolus vinblastine (given at 6 mg/m2 once weekly during weeks 5 and 8) in conjunction with p.o. 13-cis-retinoic acid (13-C-RA; given at 35 mg/m2 daily during weeks 1–8). Therapy was always given in the outpatient setting. Grade 3 constitutional symptoms (malaise, chills, fevers, anorexia) were observed in 4%–8% of treatment cycles and required a 50% reduction in the doses of rIL-2 and rIFN-. None of the patients experienced major 5-FU-related toxicities such as severe diarrhea and/or stomatitis; up to 20% of patients developed vinblastine-associated peripheral polyneuropathy, which was reversible after the cessation of therapy. 13-cis-Retinoic acid produced no significant side effect; no toxic death occurred. Among 24 patients with progressive metastatic disease, there were 4 complete remissions (lung, lymph nodes) and 6 partial remissions (lung, pleura, liver, lymph nodes, and peritoneal carcinosis), for an overall objective response rate of 42% (95% confidence interval, 22%–63%). An additional 13 patients achieved disease stabilization (54%). The median time to response was 3–4 months (range, up to 6 months); all responses are continuous. In summary, although the potential synergy of biochemotherapy plus 13-cis-retinoic acid requires further preclinical investigation, the current outpatient combination regimen (rIL-2, rIFN-a, 5-FU, vinblastine, and 13-C-RA) proved to be both safe and highly effective in patients with advanced metastatic renal-cell carcinoma. A current multiinstitutional prospectively randomized trial is comparing biochemotherapy with and without concomitant 13-C-RA against rIFN- plus vinblastine. 相似文献
83.
Background
In the literature there is some evidence that the incidence of metastases may increase after radiation treatment.Methods
In order to investigate whether radiation-induced changes in the lymphatic drainage may alter the rate of lymph node metastasis, the center part of the left hind foot of rats was irradiated with a dose of 1 x 55 Gy before inoculation of tumor cells into the irradiated part of the footpad at different time intervals. Cells of 2 different tumor lines were employed. A rarely metastasising rhabdomyosarcoma, R-l, to look for a possible enhancement of lymphatic metastases, and a readily metastasising mammary carcinoma, Cl-2, in case of a possible decrease in the rate of lymphatic metastasis from tumors growing in pre-irradiated footpads.Results
The incidence of regional lymph node metastasis decreased for R-l tumors growing in pre-irradiated footpads, but not for Cl-2 tumors. Furthermore, the average time required for lymph node metastasis to attain a reference volume of 100 mm3 is not significantly influenced by pre-irradiation of the footpad. No difference was observed in average times for doubling in volume of lymph node metastases originating from primary tumors in pre-irradiated footpads. Abscopal effects after footpad irradiation may cause a 50-fold increase in size of regional lymph nodes and, therefore, histological examination is essential for verification of lymph node metastases.Conclusions
Damage to the lymphatic system to be expected in the irradiated footpad did not enhance the incidence of regional metastasis of R-1 tumors. A reduced rate of lymphatic metastasis contradicts earlier findings of enhanced lymphatic metastasis development of R-l tumors, growing in pre-irradiated gastrocnemius muscles. The influence of irradiation on regional metastasis formation seems to be “tumor bed” dependent for R-l tumors. 相似文献84.
Willing AE Othberg AI Saporta S Anton A Sinibaldi S Poulos SG Cameron DF Freeman TB Sanberg PR 《Brain research》1999,822(1-2):246-250
One of the major issues in neural transplantation is the low survival rate (<5%) of transplanted dopamine (DA) neurons [3]. Recently it has been shown that it is possible to enhance the survival of these neurons, which in turn may decrease the amount of tissue that is required for each transplantation patient. The present paper demonstrates a novel approach for enhancing neuronal survival by co-transplantation of neuronal tissue with Testis-derived Sertoli cells (SC). This strategy could improve neuronal survival through the provision of trophic support. 相似文献
85.
T. J. De Vries Anton N. M. Schoffelmeer R. Binnekade Louk J. M. J. Vanderschuren 《Psychopharmacology》1999,143(3):254-260
Rationale: The neurobiological mechanisms underlying the persistence of drug craving in detoxified addicts are still poorly understood.
Objective: The present study was designed to evaluate dopaminergic mechanisms in drug-seeking behaviour following long-term (>3 weeks)
extinction of IV drug self-administration in rats. Methods: To that end, we studied the effects of direct and indirect dopamine (DA) agonists on reinstatement of previously extinguished
responding for heroin (50 μg/kg per injection; 14–15 daily 3-h sessions) and cocaine (500 μg/kg per injection; 10–11 daily
2-h sessions). Results: In animals with a cocaine history, priming with cocaine, the selective DA reuptake inhibitor GBR-12909 and the DA D2 receptor agonist quinpirole resulted in robust and selective reinstatement of non-reinforced nose poking behaviour in the
previously drug-paired hole. In contrast, the D1 agonist SKF-82958 failed to reinstate responding and the non-selective DA agonist apomorphine even suppressed responding
in these animals. In heroin-trained rats, heroin and GBR-12909 strongly reinstated responding, whereas all direct DA agonists
were ineffective. Again, the two highest doses of apomorphine decreased responding in these animals. In a parallel study,
the ability of DA ligands to express behavioural sensitization in animals pretreated with amphetamine or morphine was evaluated.
Interestingly, all agonists that reinstated responding in the present study caused expression of locomotor sensitization and
vice versa. Conclusions: The differences between direct and indirect agonists indicate a clear, but complex, involvement of DA in drug-seeking behaviour
long after detoxification. Moreover, the results show an important role of D2 receptor activation in the persistence of cocaine- but not heroin-seeking behaviour. Finally, the results from both studies
suggest a relationship between drug-induced reinstatement and drug hyperresponsiveness in long-term abstinent rats.
Received: 14 May 1998 / Final version: 1 December 1998 相似文献
86.
Rouzade Anton Fioramonti Garcia-Villar Theodorou & Bueno 《Alimentary pharmacology & therapeutics》1999,13(9):1235-1241
BACKGROUND: Dietary nitrates are known to produce nitric oxide in the stomach, which may influence gastric function. AIM: To investigate whether nitrate ingestion modifies gastric sensitivity to distension through a mechanism involving nitric oxide production. METHODS: Nociception, associated with gastric distension ranging from 10 to 40 mmHg, was assessed in anaesthetized rats by the amplitude of cardiovascular depressor responses. Gastric volume corresponding to each distension was recorded. The following intragastric administrations (1 mL) were performed before distension: water (control), KNO3, NaNO3, KCl, NaCl (all at 0.1 mmol/kg), standard food (0.5 g), sodium nitroprusside, a nitric oxide donor (5 mg/kg), and haemoglobin, a nitric oxide scavenger (150 mg/kg) given either with water or KNO3. RESULTS: In controls, the fall in blood pressure increased from 7.8 +/- 2.0 to 31.6 +/- 2. 7 mmHg at distending pressures from 10 to 40 mmHg, respectively. KNO3 significantly reduced the amplitude of blood pressure response for the highest distending pressures (35 and 40 mmHg), while KCl induced a reduction in blood pressure response at all gastric pressures. NaNO3 and NaCl did not induce significant changes in distension-induced depressor responses. Administration of 0.5 g of standard food or sodium nitroprusside reproduced the effect of KNO3, which was reversed by haemoglobin. None of the compounds modified the gastric pressure-volume relationship, except KNO3, which increased gastric volume for the lowest distending pressures, and haemoglobin, which reduced the volume for the highest pressure. CONCLUSIONS: Ingestion of potassium nitrate reduces the sensitivity to gastric distension, through a mechanism involving nitric oxide. 相似文献
87.
Testicular peritubular cells are located in the lamina propria of seminiferous tubules. These cells, significantly contributing to the basal membrane of seminiferous epithelium, have been studied in a number of species. However, there is a lack of data on the development of the lamina propria in the human testis. The aim of our survey was to investigate the characteristics of the lamina propria and, in particular, peritubular cells in the fetal human testes by immunohistological and stereological methods. Therefore, testes (14–39 weeks of gestation, n=45) were dissected and fixed in a 4% buffered paraformaldehyde solution. Several pieces of each testis were embedded in paraffin and processed for immunohistochemical and stereological analysis. All investigated testes have shown sex cords in the process of development and differentiation. Morphologically, peritubular cells in the lamina propria can be divided into two types: fibroblast-like (FL) and myoid-like (ML) type (cells which much resemble mature myoid cells). By immunohistochemistry, both FL and ML cells are found to be strongly positive for the intermediate filament desmin, but negative for -smooth actin. While FL cells intensively express Ki-67 demonstrating proliferative activity, ML cells are found to be negative. The basement membrane of sex cords as well as the blood vessels of the interstitium show strong positivity to collagen IV and laminin. Concerning the correlation between the appearance of the investigated antigens with the gestational age, all antigens have been expressed (in the manner described above) already in the 14th week of gestation. The stereological analysis of the number (Nv) and volume (Vv) of peritubular cells indicates a pulsatile development of these cells in the lamina propria of the human fetal testis. While the stereological variables determined for FL cells show a gradual decrease, the same variables determined for ML cells demonstrate a successive increase. It appears that the lamina propria of the fetal human testes shares many of the properties previously discovered in rodents. 相似文献
88.
Summary The potential roles of members of the fibroblast growth factor family in tumor angiogenesis and metastasis and their mechanisms of release from cells are discussed. Furthermore, we review methods of therapeutic targeting of these polypeptides. In particular, we focus on the possibility to inhibit fibroblast growth factors with drugs that mimic heparin-like cellular binding sites and thus can interfere with growth factor receptor recognition. In addition, we discuss antibodies, antisense oligodeoxynucleotides, and ribozymes as approaches to inhibit production and activity of these growth factors.List of abbreviations aFGF
acidic fibroblast growth factor (=FGF-1)
- bFGF
basic FGF (=FGF-2)
- HBGF
heparin-binding growth factor
- HGF
hepatocyte growth factor
- HSPG
heparansulfate proteoglycan
- PTN
pleiotrophin
- TGF
transforming growth factor
- VEGF
vascular endothelial cell growth factor
Presented at the symposium "New Approaches in the Therapy of Breast Cancer", Georgetown University Medical Center, Washington DC, October 1994, generously supported by an education grant from Bristol-Myers Squibb. 相似文献
89.
Leonie J. M. Rijks Gerard J. Boer Erik Endert Kora de Bruin Jan C. van den Bos Peter A. P. M. van Doremalen Willem G. E. J. Schoonen Anton G. M. Janssen Eric A. van Royen 《European journal of nuclear medicine and molecular imaging》1996,23(3):295-307
We studied the potential of both stereoisomers of 17-[123I]iodovinyloestradiol (E- andZ-[123I]IVE) and of 11-methoxy-17-[123I]iodovinyloestradiol (E-andZ-[123I]MIVE) as suitable radioligands for the imaging of oestrogen receptor(ER)-positive human breast tumours. The 17-[123I]iodovinyloestradiols were prepared stereospecifically by oxidative radio-iododestannylation of the corresponding 17-tri-n-butylstannylvi-nyloestradiol precursors. Competitive binding studies were performed in order to determine the relative binding affinity (RBA) of the unlabelled 17-iodovinyloes-tradiols for the ER in both human MCF-7 breast tumour cells and rat uterine tissue, compared with that of diethylstilboestrol (DES). Target tissue uptake, retention and uptake selectivity of their123I-labelled analogues were studied in immature female rats. All four 17-iodovi-nyloestradiols showed high affinity for the ER in human MCF-7 cells, as well as rat uterus. Their RBA for the ER showed the following order of decreasing potency: RBA of DES >Z-IVE >Z-MIVE >E-MIVE E-IVE. Neither of these 17-iodovinyloestradiols showed any significant binding to the sex hormone binding globulin in human plasma. The biodistribution studies showed ER-mediated uptake in the uterus, ovaries and pituitary, that ofE- andZ-[123I]MIVE being higher than that ofE- andZ-[123I]IVE. High target-to-non-target tissue uptake ratios, especially at longer periods after injection (up to 24 h), were exhibited by both isomers of [123I]MIVE. The uterus-to-blood uptake ratio was higher forE-[123I]MIVE. However, the uterus-to-fat uptake ratio appeared to be higher for theZ-isomer of [123I]MIVE, especially at 24 h after injection. Metabolic properties and temperature effects, which play a more important role in vivo, probably cause the discrepancies seen between in vitro and in vivo binding results. On the basis of their in vitro binding properties and in vivo distribution characteristics we conclude thatE- andZ-[123I]MIVE could be suitable radioligands for the diagnostic imaging of ER in human breast cancer. Therefore, further studies with these radioligands in mature normal and tumour-bearing rats are warranted. 相似文献
90.
1. Screening intervals according to Tabar: 1 year in women younger than 50 in order to minimize "interval cancers". 2 years in women older than 50 years. 2. Mammographic views according to Lundgren et al: 2 views at first round 1 oblique view in the following rounds, yearly. All women on risk should attend screening. The identification of useful "high risk groups" is not established. Palpation is recommended at each screening. Self-examination is recommended. Adjuvant therapy should not depend on lymph node status in screening-cancer cases. It should depend on clinical and histological "prognostic factors". 相似文献