全文获取类型
收费全文 | 2133篇 |
免费 | 182篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 100篇 |
妇产科学 | 51篇 |
基础医学 | 259篇 |
口腔科学 | 61篇 |
临床医学 | 222篇 |
内科学 | 484篇 |
皮肤病学 | 37篇 |
神经病学 | 97篇 |
特种医学 | 323篇 |
外科学 | 192篇 |
综合类 | 52篇 |
一般理论 | 5篇 |
预防医学 | 157篇 |
眼科学 | 70篇 |
药学 | 120篇 |
中国医学 | 8篇 |
肿瘤学 | 63篇 |
出版年
2019年 | 19篇 |
2018年 | 28篇 |
2017年 | 20篇 |
2015年 | 29篇 |
2014年 | 32篇 |
2013年 | 55篇 |
2012年 | 52篇 |
2011年 | 50篇 |
2010年 | 61篇 |
2009年 | 73篇 |
2008年 | 69篇 |
2007年 | 65篇 |
2006年 | 54篇 |
2005年 | 58篇 |
2004年 | 47篇 |
2003年 | 49篇 |
2002年 | 40篇 |
2001年 | 47篇 |
2000年 | 39篇 |
1999年 | 55篇 |
1998年 | 64篇 |
1997年 | 75篇 |
1996年 | 61篇 |
1995年 | 54篇 |
1994年 | 66篇 |
1993年 | 61篇 |
1992年 | 49篇 |
1991年 | 42篇 |
1990年 | 45篇 |
1989年 | 65篇 |
1988年 | 72篇 |
1987年 | 56篇 |
1986年 | 55篇 |
1985年 | 54篇 |
1984年 | 33篇 |
1983年 | 39篇 |
1982年 | 29篇 |
1981年 | 32篇 |
1980年 | 33篇 |
1979年 | 22篇 |
1978年 | 31篇 |
1977年 | 22篇 |
1976年 | 29篇 |
1975年 | 32篇 |
1974年 | 26篇 |
1973年 | 27篇 |
1972年 | 26篇 |
1971年 | 26篇 |
1970年 | 18篇 |
1967年 | 17篇 |
排序方式: 共有2319条查询结果,搜索用时 15 毫秒
991.
In retrospective series, 17.0 to 25.5 per cent of those patients with carcinoma of the colon or rectum have been found to have concurrent inguinal herniation. This observation prompted the recommendation that patients with hernias be thoroughly screened for disease of the colon and rectum. That recommendation remains controversial in part because it has not previously been prospectively evaluated. In a one year period, 202 consecutive patients with inguinal hernias completed a preoperative protocol which included: 1, gastrointestinal history; 2, rectal examination; 3, testing of at least two stool specimens with the Hemoccult (Smith Kline Diagnostics) device; 4, sigmoidoscopy, and 5, barium enema. Malignant and premalignant diseases were discovered in five patients, only one of whom had gastrointestinal symptoms. Each malignant lesion was localized (Dukes' A or B) and, therefore, highly curable. Benign disease was found in 49 patients, including polyps in eight and one instance of tight sigmoid stricture. All of the malignant and 91 per cent of the benign lesions were in patients 50 years of age and older. The association between inguinal herniation and colorectal disease was previously attributed to luminal obstruction. In the present series, however, the sole obstructing lesion was a benign stricture. Another explanation for this association must, therefore, be sought. We conclude, on the basis of the results of this experience, however, that screening for pathologic factors of the colon and rectum is warranted in otherwise asymptomatic patients who are more than 50 years old and who present with inguinal hernias. 相似文献
992.
993.
994.
I Yamamoto F R Bringhurst J T Potts G V Segre 《Journal of bone and mineral research》1988,3(3):289-295
Binding of parathyroid hormone (PTH) to circulating bovine lymphocytes was studied using, as the radioligand, a synthetic sulfur-free analog of bovine PTH, [Nle8,Nle18,Tyr34]bPTH-(1-34)amide, which was labeled to high specific activity with 125I and was purified by reverse-phase high-performance liquid chromatography. Binding of PTH to lymphocytes satisfies several criteria indicative of a specific interaction between the hormone and its receptor. Specific binding is saturable at 3.3 fmoles of radioligand bound per 10(7) cells, occurs more rapidly at 37 degrees C than at lower temperatures, and reaches equilibrium within 2 hr at 15 degrees C. Inhibition of specific binding occurs with intact PTH, with biologically active PTH analog or fragment, and with synthetic PTH antagonists, but not with biologically inactive PTH fragments, or peptide hormones unrelated to PTH antagonists, but not with biologically inactive PTH fragments, or peptide hormones receptors on lymphocytes and those previously reported with receptors in canine renal membranes, and on rat osteosarcoma cells. The dissociation constant (Kd) is approximately 10(-9) M, as calculated from the association and dissociation rate constants. This correlates very closely both with the apparent Kd, as estimated from Scatchard analysis of radioligand saturation and competition studies, and with previously reported Kd of PTH receptors in canine renal membranes and on intact rat osteosarcoma and opossum kidney cells. In addition, the relative binding affinity of intact hormone and a synthetic PTH agonist to to receptors on lymphocytes correlates closely with the relative biologic potency of these peptides in stimulating adenylate cyclase in membranes from these cells.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
995.
Freedman AN; Michalek AM; Troisi R; Mettlin CJ; Petrelli NJ; Asirwatham JE; Caporaso N 《Carcinogenesis》1997,18(4):855-856
Protective effects of oral contraceptives and high parity on the
development of colorectal cancer have been hypothesized. However, the
epidemiological data are inconsistent. This inconsistency may be due in
part to the biological heterogeneity of colorectal tumors. A recent
investigation of hepatocellular carcinoma demonstrated an association
between lack of p53 expression and oral contraceptive use. We investigated
the relationship between oral contraceptive use and other reproductive
factors with p53 over-expression in 64 post-menopausal women, 45-86 years
of age, with non-familial colorectal adenocarcinoma. Fifty per cent (32/64)
of colorectal tumors displayed nuclear over- expression of p53 protein.
Women with a history of oral contraceptive use were significantly less
likely to have p53 positive (+) tumors than women who never used oral
contraceptives (P = 0.02). In contrast, tumors from women who had never
been pregnant were more likely to be p53 + compared to tumors from parous
women (P = 0.10). These data suggest that oral contraceptive use and
pregnancy are associated with a p53 independent pathway in the development
of colorectal cancer.
相似文献
996.
997.
JE Popp 《Arthroscopy》1998,14(8):816
Effective postoperative analgesia with minimal side effects remains an important goal in enabling increasingly complex surgical procedures to be performed on an outpatient basis. In this study, we examined the efficacy of postoperative analgesia in 90 patients undergoing anterior cruciate ligament reconstruction using a patellar tendon autograft, with a 24-hour hospital stay. Patients were randomized to receive either intramuscular ketorolac supplemented by oral oxycodone, or intravenous morphine via patient-controlled analgesia (PCA) device, for postoperative analgesia. Patients were monitored for 2 hours in the recovery room, then every 4 hours until discharge, for the presence of complications of nausea, vomiting, urinary retention, pruritus, and dizziness. Pain was assessed using a visual analog scale (VAS) on the morning of postoperative day one. All patients were discharged by 24 hours after surgery. Ten (20%) of the patients receiving ketorolac/oxycodone versus 31 (79%) of those receiving PCA morphine experienced postoperative complications (P < .05). Postoperative nausea, vomiting, and urinary retention were each significantly more common in the PCA morphine group (P < .05). The incidence of pruritus and dizziness was low overall. There was no significant difference between groups in the severity of postoperative pain as assessed using a VAS. We conclude that ketorolac/oxycodone may provide comparable analgesia with fewer undesirable side effects than PCA morphine in patients undergoing anterior cruciate ligament reconstruction. Patients receiving ketorolac/oxymorphone may have a better quality recovery and more rapid discharge. (Arthroscopy 1998 Nov-Dec;14(8):816-9.) 相似文献
998.
999.
1000.
Pancreatic sparing of focal fatty infiltration 总被引:1,自引:0,他引:1