全文获取类型
收费全文 | 20993篇 |
免费 | 1060篇 |
国内免费 | 92篇 |
专业分类
耳鼻咽喉 | 242篇 |
儿科学 | 474篇 |
妇产科学 | 398篇 |
基础医学 | 2649篇 |
口腔科学 | 1133篇 |
临床医学 | 1500篇 |
内科学 | 5245篇 |
皮肤病学 | 381篇 |
神经病学 | 1825篇 |
特种医学 | 392篇 |
外科学 | 3254篇 |
综合类 | 205篇 |
一般理论 | 7篇 |
预防医学 | 1628篇 |
眼科学 | 461篇 |
药学 | 1216篇 |
中国医学 | 90篇 |
肿瘤学 | 1045篇 |
出版年
2024年 | 18篇 |
2023年 | 148篇 |
2022年 | 343篇 |
2021年 | 705篇 |
2020年 | 370篇 |
2019年 | 574篇 |
2018年 | 718篇 |
2017年 | 452篇 |
2016年 | 464篇 |
2015年 | 612篇 |
2014年 | 880篇 |
2013年 | 1036篇 |
2012年 | 1737篇 |
2011年 | 1746篇 |
2010年 | 968篇 |
2009年 | 878篇 |
2008年 | 1483篇 |
2007年 | 1521篇 |
2006年 | 1344篇 |
2005年 | 1287篇 |
2004年 | 1113篇 |
2003年 | 926篇 |
2002年 | 920篇 |
2001年 | 156篇 |
2000年 | 112篇 |
1999年 | 143篇 |
1998年 | 189篇 |
1997年 | 134篇 |
1996年 | 91篇 |
1995年 | 84篇 |
1994年 | 88篇 |
1993年 | 64篇 |
1992年 | 79篇 |
1991年 | 63篇 |
1990年 | 56篇 |
1989年 | 52篇 |
1988年 | 48篇 |
1987年 | 38篇 |
1986年 | 42篇 |
1985年 | 35篇 |
1984年 | 43篇 |
1983年 | 40篇 |
1982年 | 43篇 |
1981年 | 37篇 |
1980年 | 22篇 |
1979年 | 20篇 |
1978年 | 27篇 |
1977年 | 27篇 |
1976年 | 18篇 |
1973年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 36 毫秒
61.
Local anaesthesia for fibreoptic bronchoscopy: transcricoid injection or the "spray as you go" technique? 总被引:1,自引:1,他引:0 下载免费PDF全文
Local anaesthesia for fibreoptic bronchoscopy should be given by a safe technique that is not unpleasant to the patient and should provide acceptable conditions for the bronchoscopist. Single injection transcricoid local anaesthesia was compared with the "spray as you go" technique in patients having day case fibreoptic bronchoscopy. Patients were randomised to receive either 100 mg lignocaine by a single cricothyroid puncture or 240 mg lignocaine instilled through the bronchoscope under direct vision. Further doses were given by the operator to both groups as required. The 30 patients receiving transcricoid lignocaine coughed less (3.56 (SD 3.1) coughs/min) than the 32 patients receiving lignocaine through the bronchoscope (5.89 (4.8)/min) despite receiving a lower total dose of lignocaine (322 (25.9) v 451 (20.9) mg). Cricothyroid puncture was not associated with any complications and was not unpleasant for the patients. 相似文献
62.
M L Fernando A J Cooper Z Cernovsky C Bailey V R Velamoor 《Revue canadienne de psychiatrie》1990,35(1):77-79
Bill 7, the most recent amendment to the Ontario Mental Health Act was introduced in December 1986. It has resulted in some major changes to the practice of psychiatry, especially in provincial hospitals. We compared patients who had discharged themselves against medical advice (AMA) during the six months before the Bill was enacted, with those who discharged themselves AMA in the 12 months following. Significantly more patients discharged themselves AMA in the post- than the pre-Bill period. The majority of these were potentially treatable, acutely ill individuals with schizophrenia or affective disorder. We argue that Bill 7 has largely failed in its objective to improve the overall "quality of care" to psychiatric patients, at least in the short term. 相似文献
63.
64.
Juan J. Tarin Josep LL. Romero Fernando Bonilla-Musoles 《Journal of assisted reproduction and genetics》1994,11(9):463-469
Purpose
To characterize and predict cycles generating slowcleaving embryos in in vitro fertilization, 86 cycles were retrospectively divided into two groups (slow, n=41, and fast, n=45 according to whether the number of blastomeres per embryo on day 3 was or > than the mean of the distribution, respectively.Results
Cycles generating slowcleaving embryos were treated with luteinizing hormonereleasing hormone agonist before ovarian stimulation for a shorter period (12.1±0.5 versus 15.6±1.1 days; P0.01) and had higher immaturity grade of oocyte-corona-cumulus complexes which resulted in embryos (1.6±0.1 vs 1.3±0.1; P0.05) when compared to cycles producing fastcleaving embryos. Both variables entered in a logistic regression model applied in order to predict the probability of a cycle generating slowcleaving embryos (goodness-of-fit chisquare=180.0, degrees of freedom (df)=80, P=0.4786. This model predicted correctly 86.7% (13 of 15) of cycles generating slowcleaving embryos and 83.3% (10 of 12) of cycles producing fastcleaving embryos when the estimated probability of a cycle producing slowcleaving embryos was 0.7 or 0.3, respectively.Conclusion
Shorter treatment with hormone-releasing hormone agonist before ovarian stimulation and higher immaturity grade of oocyte-corona-cumulus complexes which result in embryos are predictive characteristics of in vitro fertilization cycles generating slow-cleaving embryos. 相似文献
65.
Prof. Dr. J. Simões da Fonseca M. Teresa Gil M. Luisa Figueira J. Guerreiro Barata Fernando Pego M. Fernanda Pacheco 《European archives of psychiatry and clinical neuroscience》1978,225(1):31-53
Summary The authors studied the behavior of normal subjects and paranoid schizophrenic patients in a simple problem-solving situation. The schizophrenics were divided into two sample groups, one of individuals under treatment and the other of individuals not under treatment.The learning process involved in this problem-solving situation is very similar to an instrumental conditioning, and can be understood by means of the following assumptions: (1) the subjects use decision functions in reacting to the stimuli, although they may be not fully aware of this; (2) learning is the result of successive transformations of these decisions in the course of time; (3) the changes have specific probabilities and are related to (a) those responses which are made to the latest stimuli, and (b) a differential probability for decision functions which were effective, or only interrupted painful reinforcement, or were completely ineffective.In schizophrenics further factors of importance were (1) an inertia factor and (2) the rigidly continued use of unsuccessful or only partially successful decision criteria.The authors used a systems theory based on Galois field theory and a calculus of operators specifying three groups of subjects. A computer program based on these hypotheses was tested in a simulation experiment.The statistical evaluation of the results showed a congruence between the theoretical approach and the experimental data.This work was carried out with financial support from the Institute de Alta Cultura, Lisbon, between 1970 and 1974 相似文献
66.
N A Fernando R L Keenan C P Boyan 《The Journal of thoracic and cardiovascular surgery》1978,75(4):531-535
The anesthetic management of 17 patients undergoing cardiac transplantation is described. Recipients had severe biventricular failure and pulmonary hypertension. Careful administration of diazepam and morphine was the preferred induction method, and pancuronium was the favored relaxant for both intubation and maintenance. Sterile technique was used in placing endotracheal tubes. Relatively small doses of morphine and diazepam, combined with 50 percent nitrous oxide, were satisfactory for the maintenance of anesthesia. Postperfusion problems were few but included poor tolerance of hypovolemia and an exaggerated hypotensive response to protamine. Isoproterenol was required to support ventricular performance, but no other cardiac stimulants were needed. Postoperative courses were uneventful. There were no operative deaths and no recall of awareness during the operation with the described method of "light" anesthesia. 相似文献
67.
Noradrenaline transport by rat heart sympathetic nerves: A re-examination of the role of sodium ions
Sergio Sánchez-Armáss Fernando Orrego 《Naunyn-Schmiedeberg's archives of pharmacology》1978,302(3):255-261
Summary The effect of sodium ion on 3H-(–)-noradrenaline (0.0875 to 0.5 M) transport by rat heart atrial hemi-appendages incubated in vitro has been studied, and the following observations made: a) When sodium was omitted (choline and lithium substitution) there was no evidence for active noradrenaline transport, and only a component that did not show saturation kinetics up to 1 M noradrenaline, remained. b) Omission of sodium or addition of 4×10–5 M desipramine inhibited noradrenaline transport to exactly the same extent, and their effects were not additive. Alprenolol did not reduce this sodium-independent transport, but tropolone lowered it somewhat. c) No evidence for corticosterone-sensitive noradrenaline transport (uptake-2) was found in this preparation at the low amine concentrations used. d) In control medium, the kinetic parameters of transport were: K
m: 0.59 ± 0.063 M and V
max: 2.44 ± 0.43 (pmoles/mg protein/min). With 26 mM sodium and the rest substituted by choline, K
m:2.26 ± 0.70 M (P0.001) and V
max: 2.74 ± 0.43 (pmoles/mg protein/min) (not significant). Also with 26 mM sodium, but with sucrose substitution, K
m: 0.76 ± 0.13 M (N.S.) and V
max: 1.06 ± 0.13 (pmol/mg/min) (P<0.05). Such results indicate that sodium only modifies the affinity of the transport system for noradrenaline, without changing V
max, and that changes in the latter are only a consequence of a reduction of the ionic strength. e) When noradrenaline transport was studied at different concentrations of external sodium, at constant ionic strength and with precautions to minimize the noradrenaline-releasing effect of low sodium, it was found that the data could be best represented by two hyperbolas placed in series. This suggests that the noradrenaline carrier has two sites for sodium, that do not interact with each other. When the same experiments were repeated in the absence of chloride, it was found that the noradrenaline transport system had lost virtually all its affinity for sodium. f) The effect of prolonged tissue incubation in the absence of sodium was found to produce a relatively small inactivation of noradrenaline transport. Such phenomenon was enhanced by raising the calcium concentration to 2 mM. 相似文献
68.
Fernando Santos James C. M. Chan James D. Hanna Kazuhiko Niimi Richard J. Krieg Jr Martha D. Wellons 《Pediatric nephrology (Berlin, Germany)》1992,6(3):262-266
To investigate the effects of growth hormone (GH) on the reversal of growth failure in uremia, recombinant human GH (rhGH) was administered to rats with chronic renal failure (CRF). The dosage of rhGH was 3 IU/day (i.p.) for 13 days after the induction of CRF by 5/6 nephrectomy. Animals were classified into four groups: untreated nephrectomized rats (NX,n=40), GH-treated nephrectomized rats (NX+GH,n=18), sham-operated rats fed ad libitum (SHAMAL,n=27), and sham-operated rats pair-fed with 10 NX rats (SHAMPF,n=10). NX and NX+GH rats developed a similar and moderate degree of CRF, serum urea nitrogen being (mean±SEM) 49±3 and 54±4 mg/dl, respectively, compared with 16±4 and 19±0 mg/dl in SHAMAL and SHAMPF groups. Weight (56.0±3.3 g) and length (3.5±0.1 cm) gains of NX rats were lower than those of SHAMAL rats (94.2±4.0 g,P<-0.0001 and 4.1±0.2 cm,P<-0.01). Growth of the SHAMPF group and the matched NX rats was not significantly different. Weight (56.2±5.0 g) and length (3.4±0.2 cm) gains of NX+GH and NX rats were similar, the beneficial effect of GH therapy on growth being observed in only those animals with more severe degrees of uremia. This growth-promoting action resulted from greater food efficiency and not from stimulated food intake. The hypercholesterolemia seen in NX rats, 81±2 mg/dl versus 55±3 mg/dl in SHAMAL (P0.0001), was not increased in the NX+GH group, 87±3 mg/dl. There was a positive and significant correlation between serum cholesterol and serum urea nitrogen values in NX and NX+GH animals. This study suggests that growth impairment of mild CRF is mainly due to malnutrition and is refractory to GH administration. GH therapy improves the growth rate of animals with advanced CRF without aggravating their lipid abnormalities. 相似文献
69.
Marco Herling George Z Rassidakis L Jeffrey Medeiros Theodoros P Vassilakopoulos Kay-Oliver Kliche Gianpaolo Nadali Simonetta Viviani Valeria Bonfante Roberto Giardini Marco Chilosi Christos Kittas Alessandro M Gianni Gianni Bonadonna Giovanni Pizzolo Gerassimos A Pangalis Fernando Cabanillas Andreas H Sarris 《Clinical cancer research》2003,9(6):2114-2120
PURPOSE: EBV-latent membrane protein-1 (LMP-1) is often expressed in Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin's lymphoma (cHL), but its clinical significance is controversial. We correlated LMP-1 with presenting features, including serum interleukin 10 levels and clinical outcome. EXPERIMENTAL DESIGN: Patients were eligible if they had biopsy-proven cHL, were untreated, HIV-1 negative, and had available archival tissue. LMP-1 expression was determined by immunohistochemistry. RESULTS: We identified 577 patients with cHL with a median age of 30 years, 55% of whom were male. LMP-1 was expressed in HRS cells of 124 patients (21%) and was detected in 78 of 461 (17%) patients with nodular sclerosis compared with 44 of 112 (39%) with mixed cellularity (P < 0.001 by Fisher's exact test). Patients with tumors with LMP-1-positive HRS cells had higher serum interleukin 10 levels (P = 0.009 by Mann-Whitney test). For the 303 patients treated with doxorubicin, bleomycin, vinblastine, and dacarbazine or equivalent regimens, the 5-year failure-free survival (FFS) for those with LMP-1-positive tumors was 74% compared with 81% for those with LMP-1-negative tumors (P = 0.23, by log-rank test). Overall survival (OS) at 5 years for patients with LMP-1-positive tumors was 90 versus 91% for patients with LMP-1-negative tumors (P = 0.8 by log-rank test). Expression of LMP-1 was not associated with different FFS and OS in patients treated with other regimens or with radiotherapy alone. CONCLUSIONS: LMP-1 was expressed by HRS cells in 21% of cHL and correlated with mixed cellularity type and higher serum interleukin 10 levels. The presence of LMP-1 was not associated with FFS or OS in uniformly treated patients. 相似文献
70.
Primary Ovarian Non-Hodgkin's Lymphoma: Outcome after Treatment with Combination Chemotherapy 总被引:1,自引:0,他引:1
Meletios A. Dimopoulos Danai Daliani William Pugh David Gershenson Fernando Cabanillas Andreas H. Sarris 《Gynecologic oncology》1997,64(3):446-450
Because the outcome of patients with primary ovarian non-Hodgkin's lymphoma (NHL) is controversial, we retrospectively analyzed experience with adults seen at the University of Texas M. D. Anderson Cancer Center from 1974 to 1993. Patients were included if at least one ovary was pathologically involved, and if combination chemotherapy was used that must have included doxorubicin for intermediate grade histologies. We identified 15 patients who constituted 0.5% of all untreated NHL and 1.5% of untreated ovarian neoplasms that presented to our instutition during this time. One patient refused therapy, leaving 14 assessable for response. Nine patients had intermediate-grade, 5 had high-grade, and none had low-grade NHL. One ovary was involved in 4 patients, and both in 10, in 7 of whom additional sites were involved, including supradiaphragmatic nodes in 2. Four patients had AAS I and 10 had AAS IV. Favorable (0 or 1) and unfavorable (>1) IPI scores were seen in 5 and 9 patients, respectively. The complete remission rate for all patients was 64%, and 5-year survival and FFS for all assessable patients were 57 and 46%, respectively. We conclude that the complete remission rate and FFS of patients with ovarian NHL treated with appropriate chemotherapy appear to be similar to that of patients with other nodal NHLs. Further work is required to determine prognostic factors in ovarian NHL. 相似文献