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41.
Rats were fed either a cereal-based or a purified casein-based diet in a foraging paradigm in which the costs of procurement and consumption were varied. The group offered the cereal-based diet consumed about 10% more calories than the group offered the casein-based diet, but both groups grew at the same rate. The intake of a control group offered a choice between the two diets was approximately 80% from the casein diet, and the growth of this group did not differ from that of the experimental groups. Variations in the cost of procurement and the cost of consumption affected the patterning of meals differentially for the two diets: changes in meal patterns tended to control the time and/or energy spent feeding. These results show that (1) meal patterns in the foraging paradigm are sensitive to subtle differences in diets, and (2) the amount of diet consumed (acceptance) and the choice between diets (preference) are determined by the economics of feeding and the nutritive quality of the foods, as well as by their palatability. 相似文献
42.
43.
Horne G; Jamaludin A; Critchlow JD; Falconer DA; Newman MC; Oghoetuoma J; Pease EH; Lieberman BA 《Human reproduction (Oxford, England)》1998,13(11):3045-3048
Insemination with donor spermatozoa is an integral part of infertility
treatment. For the last 3 years in our unit, intrauterine insemination with
donor spermatozoa (IUID) has been used in preference to vaginal
insemination. In this retrospective study, patients were offered an initial
course of five single intrauterine inseminations with cryopreserved donor
spermatozoa and treatment was then reviewed. A total of 389 patients
received 1465 inseminations. In all, 1119 cycles were monitored using
luteinizing hormone serum analyses and 346 cycles using the urine home test
kits. The clinical pregnancy rate per insemination for the cycles monitored
by the serum assay was 18.0% (202/1119) compared with the urine cycles
(13.7%, 46/346) (P <05). The pregnancy loss rate was not significantly
different (14.4%, 29/202 and 21.7%, 10/46) (serum and urine cycles
respectively). The viable clinical pregnancy rate was significantly higher
(P <03) for the serum cycles than for the cycles using the urinary
monitoring (15.5%, 173/1119 and 10.4%, 36/346 respectively). The cycles
monitored by serum assay had a significantly higher cumulative viable
clinical pregnancy rate (P <0001) of 70.2% after nine inseminations
compared with the urine monitored cycles of 54.8%. The majority of patients
opted for the serum cycles, with a minority self-selecting the urine cycles
mainly for travelling convenience. The explanation for the significant
differences between the viable clinical pregnancy rates per insemination
and the cumulative viable clinical pregnancy rates may be due to the
sensitivity of the urine home test kit or the patients' interpretation of
the result.
相似文献
44.
The preferential release of newly synthesized transmitter by a sympathetic ganglion 总被引:14,自引:0,他引:14
B. Collier 《The Journal of physiology》1969,205(2):341-352
1. The acetylcholine (ACh) store of cat's superior cervical ganglia was replaced with radioactive ACh by perfusion, during stimulation, with [(3)H]choline-Locke solution. Perfusion was continued with Locke containing unlabelled choline (Ch) (in physiological concentration) and the release of labelled and unlabelled ACh was measured.2. Electrical stimulation of the preganglionic sympathetic nerve (20/sec or 5/sec), or stimulation by perfusing with raised K, released ACh that had a lower specific radioactivity than ganglionic ACh. The proportion of released ACh that was labelled was slightly higher when stimulation was at lower frequency or by K.3. Preganglionic nerve stimulation released, in the first few minutes, ACh that had a specific activity 70-80% of ganglionic ACh, but after 5 min the proportion of label in the released ACh fell to 35-45% of that in the ganglion.4. It is concluded that newly synthesized ACh is released before equilibration with preformed stores, and the significance of this to the mechanism of transmitter release is discussed. 相似文献
45.
46.
B lymphocytes secreting IgG linked to latent transforming growth factor- beta prevent primary cytolytic T lymphocyte responses 总被引:3,自引:0,他引:3
B lymphocytes secreting IgG linked to latent transforming growth factor
(TGF)-beta (IgG-TGF-beta) prevent cytolytic T lymphocyte (CTL) responses to
unrelated antigens in mixed lymphocyte cultures (MLC) so long as resting
resident macrophages and functional Fc receptors are present. This was
shown using IgG-secreting plaque-forming cells (PFC) to sheep erythrocytes
(SRBC) obtained from popliteal lymph nodes of mice injected repeatedly in
foot pads with SRBC. Remarkably, as few as approximately 300 PFC prevented
CTL responses of 5 x 10(5) normal syngeneic spleen cells in MLC.
Supranatants of short-term cultures of PFC also prevented CTL responses,
and suppression was prevented by eliminating or dissociating IgG and
TGF-beta present in supranatants or by antibody against active TGF-beta.
Furthermore, the latency- associated peptide of latent TGF-beta was
detected in approximately 10% of foci of IgG captured from single PFC,
indicating that at least some B lymphocytes secrete IgG-TGF-beta as a
complex. Resting resident macrophages (which do not produce latent
TGF-beta) and functional Fc receptors were required for suppression,
consistent with idea that IgG- TGF-beta is taken up through Fc receptors
for IgG and that active TGF- beta, cleaved from latent TGF-beta of the
complex, is delivered directly to potentially responding CTL. If CTL
responses in man are similarly regulated by B lymphocytes, then an ongoing
B cell response in patients with chronic viral infections or bearing
immunogenic cancers may prevent effective therapeutic vaccination.
相似文献
47.
48.
Karwautz A Rabe-Hesketh S Hu X Zhao J Sham P Collier DA Treasure JL 《Psychological medicine》2001,31(2):317-329
BACKGROUND: The aim of this pilot study was to examine which unique factors (genetic and environmental) increase the risk for developing anorexia nervosa by using a case-control design of discordant sister pairs. METHODS: Forty-five sister-pairs, one of whom had anorexia nervosa and the other did not, were recruited. Both sisters completed the Oxford Risk Factor Interview for Eating Disorders and measures for eating disorder traits, and sib-pair differences. Blood or cheek cell samples were taken for genetic analysis. Statistical power of the genetic analysis of discordant same-sex siblings was calculated using a specially written program, DISCORD. RESULTS: The sisters with anorexia nervosa differed from their healthy sisters in terms of personal vulnerability traits and exposure to high parental expectations and sexual abuse. Factors within the dieting risk domain did not differ. However, there was evidence of poor feeding in childhood. No difference in the distribution of genotypes or alleles of the DRD4, COMT, the 5HT2A and 5HT2C receptor genes was detected. These results are preliminary because our calculations indicate that there is insufficient power to detect the expected effect on risk with this sample size. CONCLUSIONS: A combination of intrinsic and extrinsic factors increases the risk of developing anorexia nervosa. It would, therefore, be informative to undertake a larger study to examine in more detail the unique genetic and environmental factors that are associated with various forms of eating disorders. 相似文献
49.
Immunohistochemical localization of parathyroid hormone-related protein in parathyroid adenoma and hyperplasia 总被引:3,自引:0,他引:3
J A Danks P R Ebeling J A Hayman H Diefenbach-Jagger F M Collier V Grill J Southby J M Moseley S T Chou T J Martin 《The Journal of pathology》1990,161(1):27-33
Parathyroid hormone-related protein (PTHrP) is invoked as the cause of humoral hypercalcaemia of malignancy (HHM); it is contained in the keratinocyte layer of normal skin; and there is evidence that is is produced by fetal parathyroids. Antibodies against synthetic PTHrP peptides have been raised in rabbits and sheep. This immunohistochemical study has found that primary parathyroid adenomata and hyperplastic glands from patients with chronic renal failure stain positively with antisera against PTHrP(1-34) and PTHrP(50-69). Primary hyperplastic glands are negative. No staining with anti-PTHrP(106-141) antiserum could be detected immunohistochemically in any of the parathyroid adenomata or hyperplasia. 相似文献
50.
The manifestation of diurnal periodicity and the extent of its control by the photoperiod was assessed in three predation defense reactions which constitute either components or outcomes of a predator-prey interaction sequence. Two-hundred White Leghorn chicks were reared from hatching for one week in either 24L or 12L and then tested at one of two clock hours previously demonstrated to define peak and trough response for one of the components. Putative evidence was found for an endogenous source of the periodicity manifested in all reactions. Maintenance schedule did not entrain the periodicity, but simple room entry and handling elicited anti-predator reactions, the extent of which varied as a function of clock hour. A general model of predation defense behavior was proposed. 相似文献