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91.
Trentham-Dietz A Newcomb PA Egan KM Titus-Ernstoff L Baron JA Storer BE Stampfer M Willett WC 《Cancer causes & control : CCC》2000,11(6):533-542
Objective: Although many studies have shown that higher weight increases the risk of postmenopausal breast cancer, some aspects of this association are unclear. In order to examine the risk associated with different patterns of weight change, we analyzed data from a large case–control study of postmenopausal breast cancer.
Methods: Participants included women aged 50–79 years (n = 5031) who are newly diagnosed with invasive breast cancer in Massachusetts, New Hampshire, and Wisconsin. Similarly-aged population controls (n = 5255) were selected at random from driver's license files and Medicare beneficiary lists. Height, weight, and information on other breast cancer risk factors were ascertained by structured telephone interviews from 1992 to 1995, and logistic regression was used to estimate multivariable-adjusted odds ratios (OR) and 95% confidence intervals (CI).
Results: Women in the top quintile groups for height at age 20, recent weight, and recent body mass index had significantly increased risks of breast cancer. Among women who reached their highest adult weight at younger ages (45 years), increasing weight loss since that age was associated with a reduced risk of postmenopausal breast cancer (OR 0.90, CI 0.84–0.98, per 5 kg). However, weight loss among women whose highest weight occurred after age 45 was not associated with risk (OR 1.00, CI 0.95–1.05, per 5 kg). Weight gain since the lowest adult weight increased risk by 8% for each 5 kg of gain (OR 1.08, CI 1.06–1.11). Temporary weight cycling (weight loss followed by weight gain) was not associated with increased risk.
Conclusions: Weight gain clearly increased risk of postmenopausal breast cancer. These data lend further support to efforts aimed at helping women avoid weight gain as they age. 相似文献
92.
Dukas L Platz EA Colditz GA Willet WC Giovannucci EL 《Cancer causes & control : CCC》2000,11(10):907-914
Background: Infrequent bowel movements and use of laxatives have been hypothesized to increase risk of colorectal neoplasia. However, the few existing epidemiologic studies in humans have been inconclusive.
Purpose: To investigate prospectively the associations of bowel movement frequency and laxative use with the occurrence of adenomatous colorectal polyps in women.
Methods: A total of 17,400 women 36–61 years of age, without previous diagnosis of cancer or polyps, responded to a mailed questionnaire in 1982 that assessed bowel movement frequency and use of laxatives and had an endoscopy between 1984 and 1996. Between 1984 and 1996, 906 cases of adenomatous polyps (496 classified as small (<1 cm), 358 classified as large (1 cm) and 52 unclassified) were documented. Relative risks (RRs) of adenomas and 95% confidence intervals (CIs) were calculated using logistic regression.
Results: After controlling for adenoma risk factors, the multivariate RRs associated with having bowel movements every third day or less compared to once daily were 0.9 (95% CI: 0.7–1.2) for total colorectal adenomas, 1.0 (95% CI: 0.7–1.5) for large adenomas and 1.0 (95% CI: 0.7–1.3) for adenomas of the colon only. The multivariate RRs associated with weekly to daily laxative use compared to never use were 0.9 (95% CI: 0.7–1.1) for total colorectal adenomatous polyps, 1.0 (95% CI: 0.7–1.5) for large adenomas and 0.8 (95% CI: 0.6–1.2) for colon adenomatous polyps only.
Conclusion: These findings do not support an association between infrequent bowel movement or laxative use and risk of colorectal adenomas. 相似文献
93.
Willett WC 《The oncologist》2000,5(5):393-404
The large differences in cancer rates among countries, striking changes in these rates among migrating populations, and rapid changes over time within countries indicate that some aspect of lifestyle or environment is largely responsible for the common cancers in Western countries. Dietary fat has been hypothesized to be the key factor because national consumption is correlated with the international differences. However, detailed analyses in large prospective studies have not supported an important role of dietary fat. Instead, positive energy balance, reflected in early age at menarche and weight gain as an adult, is an important determinant of breast and colon cancers, consistent with numerous studies in animals. As a contributor to positive energy balance, and possibly by other mechanisms, physical inactivity has also been shown to be a risk factor for these diseases and in part accounts for the international differences. Although the percentage of calories from fat in the diet does not appear related to risk of colon cancer, greater risks have been seen with higher consumption of red meat, suggesting that factors other than fat per se are important. In many case-control studies, a high consumption of fruits and vegetables has been associated with reduced risks of numerous cancers, but recent prospective studies suggest these associations may have been overstated. Among the factors in fruits and vegetables that have been examined in relation to cancer risk, present data most strongly support a benefit of higher folic acid consumption in reducing risks of colon and breast cancers. These findings have been bolstered by an association between incidence of colon cancer and a polymorphism in the gene for methylenetetrahydrofolate reductase, an enzyme involved in folic acid metabolism. The benefits of folic acid appear strongest among persons who regularly consume alcohol, which itself is associated with risk of these cancers. Numerous other aspects of diet are hypothesized to influence the risks of cancers in Western countries, but for the moment the evidence is unclear. 相似文献
94.
95.
Plasma noradrenaline kinetics in humans 总被引:2,自引:0,他引:2
M Esler I Willett P Leonard G Hasking J Johns P Little G Jennings 《Journal of the autonomic nervous system》1984,11(2):125-144
Recently developed radiotracer methods for measuring the overall rate of release of noradrenaline to plasma, for the body as a whole, can be used to estimate 'total sympathetic nervous system activity' in humans. These techniques find application in clinical studies of sympathetic nervous physiology and pharmacology. The inherent weakness of any biochemical test of global sympathetic tone such as this lies in the fact that sympathetic nervous system responses typically show regional differentiation. Biochemical indices of overall sympathetic activity are insufficiently discriminating to delineate patterns of sympathetic nervous response, representing instead an algebraic sum of all regional increases or decreases in sympathetic tone. Modification of the whole-body radiotracer methodology enables organ-specific sympathetic nervous system activity to be estimated, from measurements of regional release of noradrenaline to plasma. This should facilitate investigation of possible sympathetic pathophysiology in disease states. Illustrative of potential application of the method are preliminary findings of increased renal sympathetic nervous tone in young patients with essential hypertension, and of selective activation of sympathetic nerves to the kidney by diuretics. 相似文献
96.
97.
Hu FB Willett WC Stampfer MJ Spiegelman D Colditz GA 《American journal of public health》2005,95(6):932-932; author reply 933
98.
Lu M Cho E Taylor A Hankinson SE Willett WC Jacques PF 《American journal of epidemiology》2005,161(10):948-959
The authors examined prospectively the association between dietary fat intake and cataract extraction in adult women from the Nurses' Health Study. A total of 71,083 women were followed prospectively for up to 16 years between 1984 and 2000. Dietary fat was assessed by repeated food frequency questionnaires. Incident cases of cataract extraction were determined by a biennial questionnaire. The multivariate-adjusted relative risk for the highest compared with the lowest quintile of total fat intake was 1.10 (95% confidence interval (CI): 0.99, 1.22; p(trend) = 0.01). Women in the highest quintile of long-chain omega-3 fatty acid had a 12% lower risk of cataract extraction compared with those in the lowest quintile (relative risk = 0.88, 95% CI: 0.79, 0.98; p(trend) = 0.02). Total fish intake was inversely associated with cataract (for intake of > or = 3/week vs. <1/month: relative risk = 0.89, 95% CI: 0.81, 0.98; p(trend) = 0.01). The authors' findings suggest that higher intake of long-chain omega-3 fatty acid (eicosapentaenoic acid and docosahexaenoic acid) and consumption of fish may modestly reduce the risk of cataract. 相似文献
99.
Sutcliffe S Giovannucci E De Marzo AM Willett WC Platz EA 《American journal of epidemiology》2005,162(9):898-906
Early life sexual factors, including histories of sexually transmitted infections, young-onset prostatitis, and frequency of ejaculation, were investigated in relation to lower urinary tract symptoms (LUTS) in a large case-control study nested within the Health Professionals Follow-up Study. In 1992, study participants were asked to provide information on their histories of sexually transmitted infections, prostatitis, ejaculation frequency, surgery for an enlarged prostate, and LUTS. Information on prostate surgery and LUTS was updated every 2 years. LUTS cases were defined as men who reported surgery for an enlarged prostate or high-moderate to severe LUTS (> or = 15 points on the American Urological Association symptom index) on any study questionnaires (n = 4,608). Controls were men who did not report surgery for an enlarged prostate and who scored 0-7 points on the American Urological Association symptom index on all questionnaires (n = 17,967). History of gonorrhea (adjusted odds ratio = 1.76, 95% confidence interval: 1.43, 2.15) or young-onset prostatitis (adjusted OR = 1.55, 95% confidence interval: 1.22, 1.96) was positively associated with LUTS. No association was observed between ejaculation frequency in early adulthood and LUTS. These results suggest that early genitourinary infections may contribute to later development of LUTS, although confirmation in additional population settings is warranted. 相似文献
100.
OBJECTIVE: Coffee consumption is associated with reduced risk of type 2 diabetes, but the mechanism is not clearly understood. Elevated C-peptide, as a marker of insulin secretion, has been linked to insulin-resistant type 2 diabetes. In this study, we examined consumption of caffeinated and decaffeinated coffee and total caffeine in relation to concentrations of plasma C-peptide. RESEARCH DESIGN AND METHODS: Plasma C-peptide concentrations were measured in a cross-sectional setting among 2,112 healthy women from the Nurses' Health Study I who provided blood samples in 1989-1990. Consumption of caffeinated and decaffeinated coffee and total caffeine was assessed using a semiquantitative food-frequency questionnaire in 1990. RESULTS: Intakes of caffeinated and decaffeinated coffee and caffeine in 1990 were each inversely associated with C-peptide concentration in age-adjusted, BMI-adjusted, and multivariable-adjusted analyses. In multivariable analysis, concentrations of C-peptide were 16% less in women who drank >4 cups/day of caffeinated or decaffeinated coffee compared with nondrinkers (P < 0.005 for each). Women in the highest quintile compared with the lowest quintile of caffeine intake had 10% lower C-peptide levels (P = 0.02). We did not find any association between tea and C-peptide. The inverse association between caffeinated coffee and C-peptide was considerably stronger in obese (27% reduction) and overweight women (20% reduction) than in normal weight women (11% reduction) (P = 0.005). CONCLUSIONS: Our findings suggest a potential reduction of insulin secretion by coffee in women. This reduction may be related to other components in coffee rather than caffeine. 相似文献