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1.
The authors examined the possibility that ethane 1,2-dimethanesulphonate (EDS) has a cytotoxic effect on spermatogenesis that is not secondary to androgen withdrawal resulting from the well known cytotoxic effect of EDS on Leydig cells. Adult male rats were implanted with polydimethylsiloxane (PDS) capsules containing testosterone (T) and estradiol (E), and were simultaneously injected with EDS. The PDS-TE implants, by inhibiting luteinizing hormone (LH) production, prevented Leydig cells from repopulating the testis and clamped testosterone within the seminiferous tubules at increasing concentrations relative to implant size. In rats that received EDS alone, the number of advanced spermatids per testis was significantly reduced by 2 weeks, but within 8 weeks returned to the numbers maintained in vehicle-injected control rats or in vehicle-injected rats that received testosterone- and estradiol-filled capsules of 24 cm and 0.1 cm, respectively (PDS-24TE). Surprisingly, in rats that received an EDS injection plus PDS-24TE implants, the number of advanced spermatids per testis was significantly reduced at 8 weeks and severe seminiferous tubule atrophy occurred despite the fact that the testosterone concentration was sufficient to quantitatively maintain spermatogenesis in vehicle-injected rats. In rats injected with EDS and implanted with 24 cm testosterone but not estradiol-filled capsules (PDS-24T), the advanced spermatid number per testis was significantly higher than that in the EDS plus PDS-24TE rats, but significantly lower than that in control rats. These results suggest that EDS may have a cytotoxic effect on the seminiferous epithelium that is independent of the elimination of Leydig cells, and the EDS and estradiol act synergistically to exert a profound toxic effect on spermatogenesis. 相似文献
2.
Cora E Lewis Susan K Ewing Brent C Taylor James M Shikany Howard A Fink Kristine E Ensrud Elizabeth Barrett-Connor Steven R Cummings Eric Orwoll 《Journal of bone and mineral research》2007,22(2):211-219
We examined determinants of nonvertebral fracture in elderly men from six U.S. communities followed an average of 4.1 years. Six clinical risk factors predicted fracture risk independent of hip BMD: tricyclic antidepressant use, previous fracture, inability to complete a narrow walk trial, falls in previous year, age > or =80 years, and depressed mood. INTRODUCTION: There are few prospective studies of fracture determinants in men. We examined the associations between a comprehensive set of clinical risk factors and risk of nonspine fracture in older men and whether determinants of fracture risk were independent of total hip BMD. MATERIALS AND METHODS: A total of 5995 men > or =65 years of age were recruited from six communities in the Unites States and followed prospectively for an average of 4.1 years. Baseline assessments of demographic, lifestyle, medical history, functional status, anthropometry, and cognitive, visual, and neuromuscular function were assessed by questionnaire or examination. Triannual mailed questionnaires ascertained incident fracture; reported fractures were adjudicated by physicians using medical records and X-ray reports. Proportional hazards models were used to develop multivariable models, selecting variables and controlling for BMD. RESULTS: Of 5876 men, 4.7% (N = 275) reported an incident nonspine fracture during follow-up (11.46/1000 person-years). Tricyclic antidepressant use (hazard ratio [HR], 2.36; 95% CI, 1.25-4.46), history of fracture at or after age 50 (HR, 2.07; 95% CI, 1.62-2.65), inability to complete a narrow walk trial (HR, 1.70; 95% CI, 1.23-2.34), falls in previous year (HR, 1.59; 95% CI, 1.23-2.05), age > or =80 years (HR, 1.33; 95% CI, 1.01-1.76), depressed mood (HR, 1.72; 95% CI, 1.00-2.95), and decreased total hip BMD (HR, 1.53; 95% CI, 1.34-1.74) were independently related to increased risk. Compared with having none (48.0% of men), having three or more of the clinical risk factors (4.9% of men) increased fracture risk 5-fold, independent of BMD. Having three or more risk factors and being in the lowest tertile of BMD was associated with a 15-fold greater risk than having no risk factors and being in the highest BMD tertile. CONCLUSIONS: Several clinical risk factors were independently associated with nonspine fractures in elderly men. The combination of multiple risk factors and low BMD was a very powerful indicator of fracture risk. 相似文献
3.
M M Walther P J Kragel E Trahan D Venzon H C Blair P H Schlesinger C Jamai-Dow M W Ewing C E Myers W M Linehan 《Endocrinology》1992,131(5):2263-2270
The antineoplastic properties of suramin, a polyanionic agent with demonstrated antigrowth factor activity, are under evaluation in vitro, in vivo, and in clinical trials. Suramin has been shown to have antitumor activity in patients with advanced, hormone refractory prostate cancer. During these trials, significant resolution of osseous pain was observed in nearly three quarters of the patients treated with suramin. To evaluate the effect of suramin on bone cells, we studied the effect of suramin on bone resorption in a neonatal mouse calvarial assay. Suramin inhibited bone-resorbing activity in a dose-related fashion and had an additive effect with calcitonin. Calvaria pretreated with suramin had less bone-resorbing activity, fewer attached osteoblasts, and less medium alkaline phosphatase activity than control calvaria. Suramin also inhibited osteoclastic release of tritiated proline from labeled bone in a dose-dependent fashion. The effect of metastatic prostate carcinoma on bone is incompletely understood, but may be moderated by tumor-produced factors and/or cytokines. The effects of several such agents, therefore, were examined in combination with suramin. Bone resorption induced by PTH, epidermal growth factor, tumor necrosis factor, and a tumor-produced factor, PTH related-protein, was blocked by suramin. The ability of suramin to inhibit the bone-resorbing effects of several cytokines suggests that its mechanism may involve direct action on bone metabolism. Autoradiography performed on calvaria treated with labeled suramin demonstrated heavy deposition of suramin on the outer surface of the matrix, adjacent to osteoblasts and osteoclasts lining the outer table, suggesting that bone cells may be subject to high local concentrations of the drug, in keeping with this hypothesis. 相似文献
4.
Visual assessment of urethrovesical junction mobility 总被引:1,自引:1,他引:0
The aim of the study was to compare visual assessment of anterior vaginal wall descent with the Q-tip test in evaluating urethrovesical junction mobility. One hundred and eleven patients with prolapse and/or urinary incontinence were examined in the supine lithotomy position with an empty bladder. Maximum straining Q-tip tests and maximum descent of the anterior vaginal wall were measured. Using each centimeter of descent as a cutoff value, the sensitivities, specificities and positive and negative predictive values were compared to those of the Q-tip test. As the cutt-off points were moved distally, specificity increased at the expense of sensitivity. There was no single cut-off point that provided adequate sensitivity and specificity to be clinically useful to replace the Q-tip test. It was concluded that visual assessment of anterior vaginal wall descent does not provide diagnostic accuracy and acceptable sensitivity and specificity to determine urethrovesical junction mobility. Other methods should be employed to assess support.Editorial Comment: Many clinicians claim that they can assess urethrovesical junction mobility visually and thus avoid employing other means, such as the Q-tip test, ultrasonography, bead-chain cystography or fluoroscopy. Montella et al. evaluate a technique of visual assessment of urethrovesical junction mobility based on the International Continence Society's Standardization of Terminology of Female Organ Prolapse and Pelvic Floor Dysfunction as compared to evaluation with the Q-tip test. Their results clearly indicate that this technique (measurement of the descent of point Aa) does not provide adequate sensitivity or specificity in determining urethrovesical junction descent compared to the Q-tip test. Although this technique was only compared to the Q-tip test and not all other modalities available, it is doubtful that visual assessment of anterior wall descent at any level would correspond to urethrovesical junction mobility, as is discussed very succinctly by the authors. 相似文献
5.
目的:对临床确诊糖尿病患同时测定血清葡萄糖(Glu)及糖化血清蛋白(GSP)的含量,观察二的关系,以及糖化血清蛋白水平对于评价近期(2—3周)糖尿病患血糖在体内变化的临床意义进行了观察。方法:血清葡萄糖、糖化血清蛋白测定均采用酶法测定。结果:178例糖尿病患Glu、GSP均正常3l例占17.4%;Glu、GSP均增高107例占60.1%;Glu正常、GSP增高15例占8.43%;Glu增高、GSP正常25例占14%。结论:糖化血清蛋白的含量不受即时血糖的影响,二的变化不成比例性,对评价糖尿病患2~3周病情的控制是一项灵敏可靠的指标,尤其对于住院病人的治疗与监控有一定的意义。 相似文献
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9.
Abstract This study illustrates how the Total Life Concept (TLC) program originated by AT&T was successfully transplanted to another work site, Sandia National Laboratories. Demographics of the participants at A T&T and Sandia differ and make comparisons difficult, but it is possible to assess program impact in terms of participation rates for each program. The original AT&T TLC pilot study had three major components: orientation, testing, and risk interpretation; lifestyle-improvement courses; and activities to promote health. Sandia kept the three major components of the AT&T TLC concept and made some modifications to meet Sandia's needs. Sandia's experience of adopting a model program and tailoring it to local needs worked well, demonstrating that an existing model can be successfully altered to meet the needs of different companies in varied settings. 相似文献
10.
Day DJ; Speiser PW; Schulze E; Bettendorf M; Fitness J; Barany F; White PC 《Human molecular genetics》1996,5(12):2039-2048
Steroid 21-hydroxylase deficiency is among the most common inborn errors of
metabolism in man. Characterization of mutations in the 21- hydroxylase
gene (CYP21) has permitted genetic diagnosis, facilitated by the polymerase
chain reaction (PCR). The most common mutation is conversion of an A or C
at nt656 to a G in the second intron causing aberrant splicing of mRNA.
Homozygosity for nt656G is associated with profoundly deficient adrenal
cortisol and aldosterone synthesis, secondary hypersecretion of adrenal
androgens, and a severe form of congenital adrenal hyperplasia (CAH)
characterized by ambiguous genitalia and/or sodium wasting in newborns.
During the course of genetic analysis of CYP21 mutations in CAH families,
we and others have noticed a number of relatives genotyped as nt656G
homozygotes, yet showing no clinical signs of disease. A number of lines of
evidence have led us to propose that the putative asymptomatic nt656G/G
individuals are incorrectly typed due to dropout of one haplotype during
PCR amplification of CYP21. For prenatal diagnosis, we recommend that
microsatellite typing be used as a supplement to CYP21 genotyping in order
to resolve ambiguities at nt656.
相似文献