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21.
Chattopadhyay P Pakstis AJ Mukherjee N Iyengar S Odunsi A Okonofua F Bonne-Tamir B Speed W Kidd JR Kidd KK 《European journal of human genetics : EJHG》2003,11(10):760-769
We have constructed haplotypes based on normal variation at six polymorphic sites-five single nucleotide polymorphisms (SNPs) and one short tandem repeat polymorphism (STRP)-at the RET locus for samples of normal individuals from 32 populations distributed across the major continental regions of the world. The haplotyped system spans 41.6 kilobases and encompasses most of the coding region of the gene. All of the markers are polymorphic in all regions of the world and in most individual populations. Expected heterozygosities for the six-site haplotypes range from 82 to 94% for all populations studied except for two Amerindian groups from the Amazon basin at 61 and 76%. Individual populations had from four to eight haplotypes with frequencies exceeding 5%. In general, African, southwest Asian and European groups have the highest numbers of total and of commonly occurring haplotypes; the lowest numbers are observed in Amerindian populations. Overall linkage disequilibrium (LD) for the five SNP sites was very significant (P=0.001) for all the non-African populations, but significant at that level for only one of the seven African populations. In general, the permutation-based xi coefficient that quantifies overall LD tends to increase the farther the population is from Africa, but variability of this measure of LD is often large within geographic regions. Pairwise LD measures among the SNPs also show considerable variation among populations. Association of STRP alleles with the SNP-defined background haplotypes is generally higher outside of Africa than in Africa, but is highly variable. 相似文献
22.
Ganta SR Piesco NP Long P Gassner R Motta LF Papworth GD Stolz DB Watkins SC Agarwal S 《Journal of biomedical materials research. Part A》2003,64(2):242-248
Urethanes are frequently used in biomedical applications because of their excellent biocompatibility. However, their use has been limited to bioresistant polyurethanes. The aim of this study was to develop a nontoxic biodegradable polyurethane and to test its potential for tissue compatibility. A matrix was synthesized with pentane diisocyanate (PDI) as a hard segment and sucrose as a hydroxyl group donor to obtain a microtextured spongy urethane matrix. The matrix was biodegradable in an aqueous solution at 37 degrees C in vitro as well as in vivo. The polymer was mechanically stable at body temperatures and exhibited a glass transition temperature (Tg) of 67 degrees C. The porosity of the polymer network was between 10 and 2000 microm, with the majority of pores between 100 and 300 microm in diameter. This porosity was found to be adequate to support the adherence and proliferation of bone-marrow stromal cells (BMSC) and chondrocytes in vitro. The degradation products of the polymer were nontoxic to cells in vitro. Subdermal implants of the PDI-sucrose matrix did not exhibit toxicity in vivo and did not induce an acute inflammatory response in the host. However, some foreign-body giant cells did accumulate around the polymer and in its pores, suggesting its degradation is facilitated by hydrolysis as well as by giant cells. More important, subdermal implants of the polymer allowed marked infiltration of vascular and connective tissue, suggesting the free flow of fluids and nutrients in the implants. Because of the flexibility of the mechanical strength that can be obtained in urethanes and because of the ease with which a porous microtexture can be achieved, this matrix may be useful in many tissue-engineering applications. 相似文献
23.
Sudha Sumi Mitra Krishnapillai Sreekumar 《Macromolecular chemistry and physics.》1997,198(5):1611-1621
Poly[N-(2-aminoethyl)acrylamido]triethylammonium dichloroiodate, tetrachloroiodate and dibromoiodate resins have been developed as a new class of heterogeneous reagents. The use of the polyhalide derivatives for the selective iodination of aromatic amines and phenols is described. The influence of the various reaction parameters including nature of the solvent, effective molar concentration of the reagent and temperature were investigated to find out the optimum reaction conditions for achiveing selectivity for monoiodination. 相似文献
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25.
Metabolism and elimination of rhodamine 123 in the rat 总被引:1,自引:0,他引:1
Trevor W. Sweatman Ramakrishnan Seshadri Mervyn Israel 《Cancer chemotherapy and pharmacology》1990,27(3):205-210
Summary Little is known of the pharmacology of rhodamine 123 (RH-123), an agent reported to have carcinoma-selective experimental antitumor activity. Accordingly, using a high-performance liquid chromatographic assay system with fluorescence detection, we examined the plasma decay and the biliary and urinary elimination of parent drug and metabolites in female Sprague-Dawley rats receiving RH-123 at an intravenous dose (5 mg/kg) equivalent to the therapeutic dose used in murine tumor models. Following drug administration to unconscious animals, plasma levels of drug-associated fluorescence fell in a triphasic manner (t1/2, 15 min; t1/2, 1 h; t1/2, 4.7 h). In plasma, unchanged drug predominated but lower levels of the deacylated metabolite rhodamine 110 (RH-110) and two unknowns were also detectable throughout the study. Drug fluorescence was recovered extensively in both urine and bile. In unconscious animals with ureteral cannulae, urinary excretion (11.4% of the dose in 6 h) occurred predominantly as unchanged RH-123 (97% of the total), with low levels of RH-110 (2.4%) and two unknowns (<0.6% combined) also being present. Similarly dosed conscious animals (without surgical intervention) housed in metabolic cages showed a comparable pattern of urinary excretion, with 11.9% of the drug dose being recovered in 6 h and 21.9%, by 48 h. Biliary drug elimination accounted for 8% of the delivered dose in 6 h in unconscious animals and for 11% by 36 h in conscious animals fitted with biliary cannulae. In contrast to urinary excretion, in which unchanged drug predominated, only 50% of the fluorescence recovered in bile was attributable to RH-123. The remainder was due to a number of products that were detectable throughout the study. Of these, one present at significant levels was identified as a glucuronide conjugate of RH-123, based on the liberation of parent drug when the purified metabolite was incubated with -glucuronidase or hydrolyzed with 1 N hydrochloric acid. Further studies with a radiolabeled form of RH-123 are necessary to establish the identity of the remaining unknowns disclosed in this work.This work was supported in part by research grants CA 44890 (T.W.S.) and CA 37082 (M.I.) from the National Cancer Institute, National Institutes of Health, United States Public Health Service 相似文献
26.
27.
Effective use of blood in elective surgical procedures 总被引:1,自引:0,他引:1
The preoperative requests for crossmatching of blood in elective surgical procedures were studied at the Flinders Medical Centre, South Australia. The study revealed that surgeons order crossmatched blood on the basis of habit. This led to considerable time-expiry of blood, and to unnecessary use of laboratory personnel's time and reagents. The statistical information collected during the study was used to educate the surgeons to change their blood-ordering practice. In procedures where excessive blood loss is unlikely to occur, as a stand-by, a "group-and-screen" procedure was substituted for crossmatching. A firm recommendation for maximum blood order in elective surgical procedures was also made. It is estimated that this approach would save approximately $80,000 per year per 350-bed general hospital in Australia. 相似文献
28.
Julia Redburn Sudha Sundar M Usherwood Monica Roche 《Journal of obstetrics and gynaecology》2004,24(5):552-556
This study aims to assess trends in compliance with current colposcopy guidelines in 10 gynaecological units in four English counties since 1996; to identify constraints on compliance and suggest change in practice. All 10 gynaecology units in Oxfordshire, Buckinghamshire, Northamptonshire and Berkshire participated. Data were collected prospectively by colposcopists from 23,500 new referrals across a 55-month period from September 1996 to March 2001. The Oxford Cancer Intelligence Unit performed collation, quality assurance and retrieval of data for incomplete records. Audit results were disseminated annually to colposcopists via the Regional Colposcopy Group. Colposcopy waiting times exceeded the standards, but waiting times for high-grade referrals showed statistically significant improvement. Six standards were achieved; relating to accuracy, appropriateness of management and outcomes. The seven unmet standards relate to waiting times, colposcopist's caseload, follow-up policy and the proportion of cervical epithelial neoplasia (CIN) on histology. Changes in practice are suggested, constraints on compliance are identified and the appropriateness of some guidelines is questioned. 相似文献
29.
E S Zachariah M Naidu L Seshadri 《International journal of gynaecology and obstetrics》2006,92(1):23-26
OBJECTIVE: To compare the efficacy of intravenous ergometrine, intramuscular oxytocin, and oral misoprostol in the control of postpartum hemorrhage. METHODS: Mean blood loss, rates of blood loss between 500 and 1000 ml, hematocrit fall greater than 10%, and need for additional oxytocic agents and nature and rates of adverse effects were assessed in this prospective, randomized, controlled study. RESULTS: All outcomes were similar in the 3 groups. The main adverse effects in the misoprostol group were temperatures higher than 99 degrees F, which normalized within 2 h and shivering, which was mild and self-limiting. CONCLUSIONS: Oral misoprostol is as effective as conventional oxytocic agents in preventing postpartum hemorrhage and can be recommended for use in low-resource settings. 相似文献
30.
Six factorially designed studies evaluated the effects of different schedules of electroconvulsive shocks (ECSs) on alpha-2 adrenoceptor function in the rat brain. Attenuation of the hypomotility response to a clonidine challenge was taken to indicate alpha-2 adrenoceptor downregulation, a putative mediator of antidepressant action. Six daily and six alternate-day ECSs were shown separately to produce this receptor change. Three alternate-day ECSs produced comparable downregulation for a comparable period as six daily ECSs; this suggests that ECS produces time-dependent effects. No changes were elicited with a single ECS, which indicates that a single ECS may not influence alpha-2 receptor function. Three daily ECSs produced brief downregulation, which has implications for receptor dynamics as a function of the ECS schedule. Finally, maintenance ECSs sustained alpha-2 adrenoceptor downregulation over 6 weeks, which suggests a possible neurochemical basis for maintenance electroconvulsive therapy. The clinical relevance and scope for further research are discussed. 相似文献