全文获取类型
收费全文 | 3190557篇 |
免费 | 254848篇 |
国内免费 | 5755篇 |
专业分类
耳鼻咽喉 | 46143篇 |
儿科学 | 102727篇 |
妇产科学 | 85975篇 |
基础医学 | 452233篇 |
口腔科学 | 91151篇 |
临床医学 | 290452篇 |
内科学 | 621544篇 |
皮肤病学 | 66300篇 |
神经病学 | 265004篇 |
特种医学 | 127117篇 |
外国民族医学 | 1305篇 |
外科学 | 480935篇 |
综合类 | 74341篇 |
现状与发展 | 3篇 |
一般理论 | 1289篇 |
预防医学 | 257605篇 |
眼科学 | 74443篇 |
药学 | 238593篇 |
6篇 | |
中国医学 | 6061篇 |
肿瘤学 | 167933篇 |
出版年
2018年 | 33469篇 |
2017年 | 25680篇 |
2016年 | 28344篇 |
2015年 | 32005篇 |
2014年 | 45755篇 |
2013年 | 69385篇 |
2012年 | 94552篇 |
2011年 | 99924篇 |
2010年 | 58874篇 |
2009年 | 56364篇 |
2008年 | 94620篇 |
2007年 | 100795篇 |
2006年 | 101354篇 |
2005年 | 98524篇 |
2004年 | 95065篇 |
2003年 | 91914篇 |
2002年 | 90195篇 |
2001年 | 146877篇 |
2000年 | 152016篇 |
1999年 | 128914篇 |
1998年 | 37619篇 |
1997年 | 34041篇 |
1996年 | 33856篇 |
1995年 | 32625篇 |
1994年 | 30587篇 |
1993年 | 28551篇 |
1992年 | 103622篇 |
1991年 | 100630篇 |
1990年 | 97232篇 |
1989年 | 93629篇 |
1988年 | 86709篇 |
1987年 | 85402篇 |
1986年 | 80624篇 |
1985年 | 77142篇 |
1984年 | 58498篇 |
1983年 | 49805篇 |
1982年 | 29974篇 |
1981年 | 26892篇 |
1979年 | 54478篇 |
1978年 | 38151篇 |
1977年 | 32268篇 |
1976年 | 30299篇 |
1975年 | 32216篇 |
1974年 | 39267篇 |
1973年 | 37433篇 |
1972年 | 34898篇 |
1971年 | 32131篇 |
1970年 | 30407篇 |
1969年 | 28130篇 |
1968年 | 25618篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
C.A. AMEZCUA H.R. MACDONALD† C.A. LUM W. YI‡ L.I. MUDERSPACH† L.D. ROMAN† & J.C. FELIX† 《International journal of gynecological cancer》2006,16(3):1336-1341
In this study, we examine the prevalence of finding isolated tumor cells (ITCs) in negative lymph nodes of endometrial cancer patients using immunohistochemistry. Seventy-six endometrial cancer patients with lymph nodes histologically negative for metastatic disease were examined. Nodal tissue sections were stained with anticytokeratin antibodies AE-1 and CAM 5.2. Nodes with single or groups of cells (two to four cells) < or =0.2 mm and showing cytokeratin reactivity were positive for ITCs. Findings were compared to features of the primary tumor and patient outcome. ITCs were present in 31 of 1712 lymph nodes. Fifteen (19.7%) patients had ITC-positive nodes. ITCs involved only pelvic nodes in nine cases, only para-aortic nodes in five cases, and pelvic and para-aortic in one case. Tumor in adnexa was the only pathologic feature associated with nodal ITCs (P= 0.0485). All 15 patients with nodal ITCs were alive at follow-up. One (6.7%) patient suffered recurrent disease but was alive at last encounter. Disease recurred in 5 (8.8%) of 57 patients without nodal ITCs. Two are alive without disease, two alive with disease, and one died from her cancer. In summary, a significant proportion of endometrial cancer patients have ITCs detected by immunohistochemistry in histologically negative regional lymph nodes. 相似文献
992.
Matthew J Matasar Ellen K Ritchie Nathan Consedine Carol Magai Alfred I Neugut 《European journal of cancer prevention》2006,15(4):367-370
Despite significant improvements in the prognosis of acute promyelocytic leukemia brought about by therapeutic advances, understanding of the epidemiology of acute promyelocytic leukemia remains limited. Earlier reports have suggested that Hispanics may have an increased incidence of acute promyelocytic leukemia, but no systematic analysis of national data has yet been reported. We performed a retrospective cohort study, using data from the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute from 1992-2001 in order to compare leukemia incidence rates as a function of race and ethnicity. We identified 709 cases of acute promyelocytic leukemia and analyzed incidence rates by race and sex. Hispanics were not found to have greater lifetime incidence rates than whites, with an incidence relative rate (IRR) of 0.86 that of whites (P=0.17). The age distribution among Hispanics was significantly different from non-Hispanic whites, with greater incidence rates for children ages 1-19 years (IRR=1.9, P=0.02) and adult ages 20-44 years (IRR=1.6, P=0.004). Blacks had lower lifetime incidence rates than non-Hispanic whites (IRR=0.75, P=0.04), Hispanics (IRR=0.64, P=0.007), and Asians (IRR=0.67, P=0.03). Asians did not differ from non-Hispanic whites in lifetime or age-specific incidence rates. These results indicate that while US Hispanics do not have greater lifetime incidence rates of acute promyelocytic leukemia, blacks have lower incidence rates of acute promyelocytic leukemia than Hispanics, non-Hispanic whites, and Asians. 相似文献
993.
C G Arruda J M Aldrighi L A Bortolotto I N Alecrin J A F Ramires 《Gynecological endocrinology》2006,22(10):557-563
BACKGROUND: Arterial hypertension and postmenopausal reduction of estrogen levels may be involved in modifications of the stiffness of large arteries. OBJECTIVES: To evaluate the pulse-wave velocity (PWV) and indirectly the arterial stiffness in hypertensive postmenopausal women submitted to hormone therapy with estradiol alone or combined with norethisterone acetate. SUBJECTS: Forty-five hypertensive postmenopausal women were double-blindly, randomly assigned to three arms of treatment: placebo (group I); estradiol 2 mg/day (group II); or estradiol 2 mg/day and norethisterone acetate 1 mg/day (group III). METHODS: Arterial stiffness was assessed from PWV measurements of the common carotid and femoral arteries (CF-PWV) and the common carotid and radial arteries (CR-PWV) obtained using the automatic Complior(R) device, taken at baseline and after 12 weeks of treatment. RESULTS: After the 12-week treatment, values of CF-PWV and CR-PWV were not significantly different (p = 0.910 and p = 0.736, respectively) among the groups. Systolic blood pressure showed a positive correlation with CF-PWV in groups II and III (p = 0.02 and p < 0.001, respectively). CONCLUSIONS: PWV and arterial stiffness in postmenopausal hypertensive women did not reduce over a 12-week treatment with estradiol alone compared with the same period of treatment with estradiol combined with norethisterone acetate. 相似文献
994.
Gábor Márk Somfai Kata Miháltz Eszter Tulassay János Rigó 《Hypertension in pregnancy》2006,25(1):11-20
OBJECTIVE: Visual symptoms are common in patients with preeclampsia, and are caused by various underlying pathological changes in the retina. Blurred vision may be one of these symptoms. We describe three cases in which the underlying retinal pathology of blurred vision was clarified using optical coherence tomography (OCT), a novel, non-invasive ophthalmic imaging technique that provides micrometer-scale resolution images of the human retina. METHODS: Three patients with preeclampsia complained of blurred vision postpartum. In all cases, ophthalmoscopy was performed at the bedside, followed by the assessment of best corrected visual acuity, slit-lamp biomicroscopy, fluorescein angiography (FLA), and OCT. In all cases, the presence of central visual defects was examined by an Amsler-grid. RESULTS: In one case, the symptoms were bilateral. In all affected eyes, the patients complained of a relative central scotoma. Ophthalmoscopy showed edema in the affected maculae, while OCT examination clarified a serous neurosensory detachment of the macula. In one case, a neurosensory detachment was also detected in the papillomacular region of a fellow eye with no symptoms. In two cases, FLA was performed, but only in one case could we detect late leakage and subretinal exudates. The serous detachments observed showed total resolution in all cases within 5 to 10 weeks, with restoration of visual acuity. CONCLUSION: In patients with preeclampsia, OCT may provide a useful method for the precise assessment of retinal changes, distinguishing retinal edema from serous neurosensory detachments. This finding may help to clarify the pathophysiological circulatory changes seen in preeclampsia. 相似文献
995.
Vascular malformation (AVM) in the gastrointestinal tract is an uncommon, but not rare, cause of bleeding and iron deficiency anemia, especially in an aging population. While endoscopic coagulative therapy is the method of choice for controlling bleeding, a substantial number of cases require additional therapy. Adjunctive or even primary phamacotherapy may be indicated in recurrent bleeding. However, there is little evidence-based proof of efficacy for any agent. The bulk of support is derived from anecdotal reports or case series. The present review compares the outcome of AVM after no intervention, coagulative therapy or focus on pharmacological agents. Most of the literature encompasses two common AVMs, angiodysplasia and hereditary hemorrhagic telangiectasia. Similarly, the bulk of information evaluates two therapies, hormones (estrogen and progesterone) and the somatostatin analogue octreotide. Of these, the former is the only therapy evaluated in randomized trials, and the results are conflicting without clear guidelines. The latter therapy has been reported only as case reports and case series without prospective trials. In addition, other anecdotally used medications are discussed. 相似文献
996.
997.
998.
999.
BACKGROUND: Diffuse peritubular capillary (PTC) C4d deposition has been shown to be associated with relatively poor graft outcome. The significance of focal PTC C4d staining in the early post-transplant period is uncertain. METHODS: Sixty-five biopsies from 53 patients with acute rejection were graded (Banff '97 criteria), stained for C4d, monocytes and T cells, and divided into three groups according to PTC C4d: (i) focal C4d (F) (14 biopsies, 14 patients), (ii) diffuse C4d (D) (23 biopsies, 15 patients) and (iii) no C4d (N) (28 biopsies, 24 patients). The three groups were compared with respect to a variety of biopsy and clinical parameters including outcome. RESULTS: The incidence of transplant glomerulitis and glomerular monocyte infiltration were significantly greater in F (64% and 2.0+/-2.0) and D (57% and 3.4+/-2.0) than in N (11% and 0.2+/-0.2). A significantly higher proportion of F (93%) demonstrated acute cellular rejection (Banff '97 grade > or = 1A) than did D (35%). The F and D groups included significantly more females (50 and 67%, respectively) than did N (21%). The percentage of patients with a second or third transplant was higher in F (29%) and D (40%) than in N (8%) (P = 0.0589). The proportion of patients with glomerular filtration rate < 30 ml/min at 12, 24 and 48 months was higher in the D and F groups than in the N, and there was a statistically significant increasing trend in odds of this outcome occurring at 48 months across the three groups (D > F > N group) (P = 0.0416). CONCLUSION: The results suggest that the biopsy findings and clinical course in patients with focal PTC C4d staining are similar to those associated with diffuse C4d. 相似文献
1000.
Conclusions Limitation of this analysis is participation of limited centers. Though all the regions of the country are represented total
number of procedures reported are less. Isolated CABG is commonest procedure performed in 2004. Congenital surgical procedures
are more than the valvular heart disease procedure. For appropriate categorization we need standard nomenclature for various
congenital surgical procedures. 相似文献