首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2037521篇
  免费   138361篇
  国内免费   5513篇
耳鼻咽喉   27973篇
儿科学   65411篇
妇产科学   55608篇
基础医学   275729篇
口腔科学   57234篇
临床医学   193675篇
内科学   401308篇
皮肤病学   44130篇
神经病学   166880篇
特种医学   77553篇
外国民族医学   636篇
外科学   310051篇
综合类   42955篇
现状与发展   42篇
一般理论   889篇
预防医学   161134篇
眼科学   45953篇
药学   139460篇
  41篇
中国医学   3847篇
肿瘤学   110886篇
  2021年   16870篇
  2019年   17367篇
  2018年   26967篇
  2017年   22971篇
  2016年   25228篇
  2015年   27711篇
  2014年   38195篇
  2013年   55479篇
  2012年   63802篇
  2011年   67925篇
  2010年   44604篇
  2009年   44115篇
  2008年   64642篇
  2007年   67474篇
  2006年   68635篇
  2005年   66240篇
  2004年   63488篇
  2003年   60695篇
  2002年   59046篇
  2001年   83438篇
  2000年   84681篇
  1999年   72938篇
  1998年   23569篇
  1997年   21307篇
  1996年   21159篇
  1995年   19711篇
  1994年   18107篇
  1993年   16952篇
  1992年   57191篇
  1991年   55221篇
  1990年   54165篇
  1989年   52090篇
  1988年   47892篇
  1987年   47593篇
  1986年   45124篇
  1985年   43374篇
  1984年   33061篇
  1983年   28370篇
  1982年   17823篇
  1979年   30167篇
  1978年   21832篇
  1977年   18604篇
  1976年   17487篇
  1975年   18549篇
  1974年   22217篇
  1973年   21342篇
  1972年   19803篇
  1971年   18304篇
  1970年   17306篇
  1969年   16098篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
We report the case of a patient with a 13-year history of pemphigus vulgaris (PV) treated with immunosuppressive agents, prednisone and mycophenolate mofetil who had developed lesions of Kaposi's sarcoma (KS) on a sole plaque of PV that had been previously treated with intralesional injections of steroids. The lesions were surgically removed and polymerase chain reaction (PCR) demonstrated human herpesvirus-8 (HHV-8) DNA. There were neither recurrences nor later dissemination of KS following gradual decrease of the immunosuppressive therapy. We suggest that the treatment with intralesional steroids may have influenced the local reactivation of a latent infection of the virus, determining the appearance of this localized KS.  相似文献   
72.
We report a case of a prepubertal girl with juvenile primary hypothyroidism presenting as ovarian cysts and precocious puberty. The 7-year-old female was referred to our clinic because of a pelvic/abdominal mass and vaginal bleeding. Besides these findings, on physical examination we noticed the thyroid gland globally increased and the presence of secondary sexual characteristics. Based upon the clinical profile and investigations, the patient was diagnosed with juvenile primary hypothyroidism due to autoimmune thyroiditis. The cysts and precocious puberty resolved spontaneously after the simple replacement of thyroid hormone. It is important to bear in mind hypothyroidism in cases of girls presenting ovarian cysts and precocious puberty in order to avoid unnecessary surgery on the ovaries.  相似文献   
73.
OBJECTIVE: To assess the effects of adding combined estradiol/norethisterone acetate therapy (CENT) to goserelin acetate treatment (GA) of dysfunctional uterine bleeding (DUB) in perimenopausal women. METHODS: In a randomized, placebo-controlled, double-blind trial followed by an open follow-up study, 31 perimenopausal women with DUB were recruited from gynecological outpatient departments of two Dutch hospitals and randomized for treatment with either GA/placebo or GA/CENT for 6 months followed by 18 months of GA/CENT for all. The main outcome measures were abdominal pain, number of bleeding days, double-layer endometrial thickness (DET), Greene climacteric score (GCS), visual analog scale for well-being, bone mineral density (BMD) and mammographic density (BI-RAD score). RESULTS: Abdominal pain, number of bleeding days and DET decreased in both groups, the between-group difference in decrease not being statistically significant. GCS initially showed significant improvement in the GA/CENT group. BMD decreased significantly in the GA/placebo group (-4.1%) compared with the GA/CENT group (-0.3%). Another 18 months of GA/CENT did not result in a lasting difference in BMD between groups. BI-RAD scores did not differ significantly between or within the two groups. CONCLUSIONS: Adding CENT to GA treatment for DUB in perimenopausal women initially prevented BMD loss and improved climacteric complaints, while having no negative impact on vaginal bleeding, abdominal pain or BI-RAD scores. However, prolonged treatment did not result in a lasting prevention of bone loss.  相似文献   
74.
OBJECTIVE: To compare infants' discomfort, nursing-time and caregiver preference, and assess the clinical efficiency (as a secondary outcome) of hood versus facemask nebulization in infants with evolving bronchopulmonary dysplasia (BPD) in the neonatal intensive care unit. STUDY DESIGN: A prospective, open, randomized, controlled crossover clinical trial. In total, 10 infants with BPD who were on inhaled beta-agonist bronchodilators and corticosteroids were randomly assigned to receive their nebulized treatments either by a facemask, or by a hood for 2-3 days, and then crossover to receive the same treatments with the other technique for another 2-3 days. Infants' discomfort, nursing-time, caregiver preference and clinical efficiency were compared. RESULTS: At baseline there was no significant clinical difference between the groups. Nurse-time required for administering the hood nebulization (mean+/-s.e.m.: 1.9+/-0.1 min) was significantly shorter than the time for mask nebulization (12.0+/-0.6 min, P<0.0001). Infants' discomfort score was significantly lower (0.1+/-0.04) for hood versus mask nebulization (2.5+/-0.2, P<0.0001). Nurses and parents unequivocally preferred the hood treatment. During both mask and hood nebulization therapies (2-3 days) clinical efficiency was comparable. While both methods caused an immediate (20 min post) clinical improvement, the immediate respiratory assessment change score was significantly greater for the hood versus the mask nebulization (0.62+/-0.27 versus 0.13+/-0.14, P<0.05). CONCLUSIONS: Nebulization of aerosolized medications in infants with evolving BPD by hood was less time-consuming for caregivers and was much better tolerated by the infants while being at least as effective as the conventional facemask nebulization.  相似文献   
75.
Abstract: Background: Few studies have examined in depth the labor progression of multiparas to determine if there is any additional impact of being parous beyond the first birth. The objective of this study was to determine the effect of parity on labor progression in contemporary obstetric practice. Methods: Our sample consisted of all low‐risk women who delivered a term, live‐born infant from January 2002 to March 2004 at a single institution in Delaware, United States (n = 5,589). The median duration of labor by each centimeter of cervical dilation was computed for parity = 0 (n = 2,645); parity = 1 (n = 1,839); parity = 2 (n = 750); and parity = 3 + (n = 355). Results: Multiparas had a significantly faster labor progression from 4 to 10 cm (293, 300, and 313 min, respectively, for parity = 1, parity = 2, and parity = 3 +), compared with nulliparas (383 min for parity = 0), as well as a shorter second stage of labor. However, no significant differences were found in duration of the active phase or the second stage of labor among multiparas. Conclusions: Additional childbearing appears to have no effect of on the progression of labor among multiparous subgroups. The difference in duration of the active phase between nulliparas and multiparas is substantially smaller in a contemporary population. (BIRTH 33:1 March 2006)  相似文献   
76.
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   
77.
The aim of our study was to determine the incidence, timing, and severity of vaginal stenosis in patients with carcinoma of the cervix who had received pelvic and/or vaginal radiotherapy as part of their treatment. We also sought to determine if there were any predisposing factors for the development of stenosis. A retrospective chart review was undertaken for all the patients diagnosed with carcinoma of the cervix between January 1, 1990, and December 31, 2000 and treated with pelvic and/or vaginal radiation at Westmead Hospital. Since January 1, 1990, data regarding vaginal stenosis has been prospectively recorded on all the patients. Data collected included patient demographics, stage of disease, treatments administered, and incidence, timing, and severity of vaginal stenosis. One hundred and eighty-eight patients were treated. Mean age was 58.6 years. Thirteen percent of patients had stage IB disease, 45% had stage II disease, 39.5% had stage III disease, and 1.5% had stage IV disease. One hundred and seventy-nine patients returned for follow-up, and data regarding vaginal toxicity were available in 98%. Twenty-seven percent had grade 1 toxicity (partial stenosis or shortening but not complete occlusion), and 11% had grade 2 (complete occlusion). Stenosis of any grade was noted at a mean of 9.6 months and median of 7.5 months (range, 26 days-5.6 years) from completion of treatment. The only prognostic factor associated with increased risk of stenosis was age greater than 50 years (odds ratio 2.26). Vaginal stenosis is a common complication of pelvic and vaginal radiotherapy, occurring in 38% of patients. Stenosis occurs most often in the first year after treatment. Patients over the age of 50 are most at risk.  相似文献   
78.
79.
Abstract: Background: Identification of risk drinking in expectant fathers may be helpful as an important part of efforts to minimize maternal alcohol use, and as an opportunity to inform them about a problematic practice during a critical developmental stage for the couple. The purpose of this study was to evaluate the T‐ACE screening questionnaire, which asks about t olerance to alcohol, being a nnoyed by other's comments about drinking, attempts to c ut down, and having a drink first thing in the morning (“ e ye‐opener”), in the male partners of pregnant women who themselves were T‐ACE positive. Methods: Two hundred fifty‐four male partners were asked to complete the T‐ACE embedded in a health survey, the Alcohol Use Disorders Identification Test (AUDIT), and other questions about their alcohol use in the past 30 days when their pregnant partners had a median gestation of 11.5 weeks (T1). After delivery, male partners again completed the T‐ACE and quantity‐frequency questions (T2). The predictive ability of the T‐ACE and AUDIT was compared, using risk drinking (>4 drinks/day or >14 drinks/week) as the criterion standard. Results: A substantial minority of male partners had risk drinking, 31 percent at T1 and 25 percent at T2. Although the AUDIT was better than the T‐ACE as an independent predictor of risk drinking, the latter was most accurate when the tolerance threshold exceeded 2 drinks, the same established for pregnant women. The sensitivity (T1 = 84.6%, T2 = 82.8%) and specificity (T1 = 43.8%, T2 = 51.1%) of the T‐ACE at this threshold compared favorably with those of the AUDIT at the standard cut point of 8. Conclusions: The T‐ACE may be a practical way for clinicians to identify risk drinking in both pregnant women and expectant fathers. (BIRTH 33:2 June 2006)  相似文献   
80.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号