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51.
Nutritional studies on rats given a choice between two diets differing in protein content have led to the proposal that brain 5-HT content regulates protein intake [2]. Pharmacologic studies under similar conditions of dietary self-selection suggest that brain 5-HT controls carbohydrate intake [41]. We tested the effect of elevating brain 5-HT via tryptophan injection (100 mg/kg) on short-term food intake and selection by rats choosing between two diets differing in protein and carbohydrate content. Under these conditions neither total food intake nor protein and carbohydrate selection were affected despite increases of 50% in brain concentrations of 5-HT and 5-HIAA. The effect of Trp administration was selective to serotonin metabolism as brain concentrations of NE, DA and DOPAC were not affected. These results suggest that alterations in brain 5-HT content which may occur following meal ingestion may not be of physiological importance in regulating nutrient intake and selection. 相似文献
52.
Detailed investigation of factors influencing amplification efficiency and allele drop-out in single cell PCR: implications for preimplantation genetic diagnosis 总被引:16,自引:0,他引:16
Preimplantation genetic diagnosis (PGD) of single gene disorders relies on PCR-based tests performed on single cells (polar bodies or blastomeres). Despite the use of increasingly robust protocols, allele drop-out (ADO; the failure to amplify one of the two alleles in a heterozygous cell) remains a significant problem for diagnosis using single cell PCR. In extreme cases ADO can affect >40% of amplifications and has already caused several PGD misdiagnoses. We suggest that an improved understanding of the origins of ADO will allow development of more reliable PCR assays. In this study we carefully varied reaction conditions in >3000 single cell amplifications, allowing factors influencing ADO rates to be identified. ADO was found to be affected by amplicon size, amount of DNA degradation, freezing and thawing, the PCR programme, and the number of cells simultaneously amplified. Factors found to have little or no affect on ADO were local DNA sequence, denaturing temperature (94 or 96 degrees C) and cell type. Consideration of the causal factors identified during this study should permit the design of PGD protocols that experience little ADO, thus improving the accuracy of PGD for single gene disorders. 相似文献
53.
Bilateral simultaneous tubal sextuplets: pregnancy after in-vitro fertilization--embryo transfer following salpingectomy 总被引:2,自引:1,他引:2
The presence of a damaged tube has been suggested in recent studies to have
a negative effect on in-vitro fertilization (IVF) outcome. Performing
bilateral salpingectomy prior to IVF to maximize pregnancy rates may also
result in unnecessary surgery. This case is also an example of the
occurrence of interstitial pregnancy after salpingectomy. This unusual type
of ectopic pregnancy must be kept in mind when evaluating a patient
suspected of a possible early abnormal gestation after assisted
reproductive technolologies.
相似文献
54.
Amy H. Kim Paul M. Macev Ph.D. Mary A. Woo Pearl L. Yu Thomas G. Keens David Gozal Ronald M. Harper 《Somnologie - Schlafforschung und Schlafmedizin》2002,6(3):109-115
Summary Question of the Study Congenital central hypoventilation syndrome (CCHS) subjects exhibit diminished respiratory-related heart rate variation in addition to defining characteristics of CO2 insensitivity and reduced ventilatory drive during sleep. Loss of cardiovascular and breathing coupling may diminish blood pressure influences on breathing; such influences may be determined by evaluating cardiorespiratory responses to different pressor challenges.
Patients and Methods Ten children with CCHS and 10 age- and gender-matched controls were subjected to a forehead cold pressor challenge and to Valsalva maneuvers. Heart and respiratory rates and variability during 30-s baseline and 120-s challenge periods were assessed with scatterplot displays and by analysis of variance procedures.
Results Cold pressor challenges enhanced breathing efforts and increased respiratory-related heart rate variation in controls but not in CCHS patients, while lower frequency heart rate variability increased in both controls and CCHS subjects. Heart rate variation resulting from voluntary expiratory efforts was present but slightly reduced in CCHS. Respiratory and cardiac rate trends differed in control and CCHS cases.
Conclusions More-rapidly changing heart rate variation from spontaneous or reflexively-induced sources is diminished in CCHS but remains intact from voluntary expiratory efforts, as does slower variation. Loss of reflexive influences on breathing from blood pressure changes may attenuate a source of respiratory drive. 相似文献
Patients and Methods Ten children with CCHS and 10 age- and gender-matched controls were subjected to a forehead cold pressor challenge and to Valsalva maneuvers. Heart and respiratory rates and variability during 30-s baseline and 120-s challenge periods were assessed with scatterplot displays and by analysis of variance procedures.
Results Cold pressor challenges enhanced breathing efforts and increased respiratory-related heart rate variation in controls but not in CCHS patients, while lower frequency heart rate variability increased in both controls and CCHS subjects. Heart rate variation resulting from voluntary expiratory efforts was present but slightly reduced in CCHS. Respiratory and cardiac rate trends differed in control and CCHS cases.
Conclusions More-rapidly changing heart rate variation from spontaneous or reflexively-induced sources is diminished in CCHS but remains intact from voluntary expiratory efforts, as does slower variation. Loss of reflexive influences on breathing from blood pressure changes may attenuate a source of respiratory drive. 相似文献
55.
The CTLA-4 gene region of chromosome 2q33 is linked to, and associated with, type 1 diabetes. Belgian Diabetes Registry 总被引:8,自引:1,他引:8
Nistico L; Buzzetti R; Pritchard LE; Van der Auwera B; Giovannini C; Bosi E; Larrad MT; Rios MS; Chow CC; Cockram CS; Jacobs K; Mijovic C; Bain SC; Barnett AH; Vandewalle CL; Schuit F; Gorus FK; Tosi R; Pozzilli P; Todd JA 《Human molecular genetics》1996,5(7):1075-1080
Susceptibility to autoimmune insulin-dependent (type 1) diabetes mellitus
is determined by a combination of environmental and genetic factors, which
include variation in MHC genes on chromosome 6p21 (IDDM1) and the insulin
gene on chromosome 11p15 (IDDM2). However, linkage to IDDM1 and IDDM2
cannot explain the clustering of type 1 diabetes in families, and a role
for other genes is inferred. In the present report we describe linkage and
association of type 1 diabetes to the CTLA-4 gene (cytotoxic T lymphocyte
associated-4) on chromosome 2q33 (designated IDDM12). CTLA-4 is a strong
candidate gene for T cell- mediated autoimmune disease because it encodes a
T cell receptor that mediates T cell apoptosis and is a vital negative
regulator of T cell activation. In addition, we provide supporting evidence
that CTLA-4 is associated with susceptibility to Graves' disease, another
organ- specific autoimmune disease.
相似文献
56.
57.
Hemin levels in culture medium of Porphyromonas (Bacteroides) gingivalis regulate both hemin binding and trypsinlike protease production. 总被引:6,自引:6,他引:6
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Washed cells and Sarkosyl-insoluble outer membrane preparations of the black-pigmented bacteroides Porphyromonas gingivalis W50 bound hemin. The amount of hemin removed from a buffered solution by both cells and outer membranes was significantly larger if bacteria had been grown in broths supplemented with 5 mg of hemin per liter rather than none. Conversely, cells grown without supplemental hemin bound relatively little. However, all preparations bound some hemin. In addition, hemin regulated the production of significantly higher levels of trypsinlike protease by P. gingivalis W50. The nonpigmented variant, W50 BE1, showed no such responses to the levels of hemin in the growth medium. 相似文献
58.
59.
60.
Attitudes of subjects at risk and their relatives towards genetic counselling in Huntington''s chorea.
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Ninety-two patients suffering from Huntington's chorea (HC) and their spouses, and 91 subjects with an affected parent and their spouses, living in three counties of industrial South Wales, have been studied regarding their knowledge of their inheritance of the disorder. Particular attention was paid to its influence on their attitudes towards child-bearing, telling their children of the risks, and predictive tests. Only 12% of the patients were known to have received professional advice before completing their families, in contrast to 68% of the sample at risk. It is estimated that 82% of the patients and 60% of the subjects at risk had, or might have, restricted their family size had they known in time. The majority found genetic counselling helpful, but did not necessarily wish to alter their child-bearing plans in consequence. It was clear that information provided by the family alone was usually inadequate and that this applied to the present generation at risk as well as to previous generations. It was concluded that the burden of telling children the risks is too great for most parents and that professional help is needed. The long term impact of genetic counselling on the incidence of the disease is impossible to assess without continued monitoring, but preliminary results are encouraging. Attitudes towards a predictive test reflected much conflict: although 56% overall wished to take one, only 40% of those who were parents wished to know if they were at risk of passing the gene on to their children. Few subjects reported severe social stress on learning of their genetic risks, but about one in four reported experiencing significant anxiety. 相似文献